Retrograde amnesia in patients with diencephalic, temporal lobe or frontal lesions.

PubMed

Kopelman, M D; Stanhope, N; Kingsley, D

1999-07-01

Patients with focal diencephalic, temporal lobe, or frontal lobe lesions were examined on various measures of remote memory. Korsakoff patients showed a severe impairment with a characteristic 'temporal gradient', whereas two patients with focal diencephalic damage (and anterograde amnesia) were virtually unimpaired on remote memory measures. Patients with frontal lobe pathology were severely impaired in the recall of autobiographical incidents and famous news events. Patients with temporal lobe pathology showed severe impairment but a relatively 'flat' temporal gradient, largely attributable to herpes encephalitis patients. From recognition and cued recall tasks, it is argued that there is an important retrieval component to the remote memory deficit across all the lesion groups. In general, the pattern of performance by the frontal lobe and temporal lobe groups was closely similar, and there was no evidence of any major access/storage difference between them. However, laterality comparisons across these groups indicated that the right temporal and frontal lobe regions may make a greater contribution to the retrieval of past episodic (incident and event) memories, whereas the left temporal region is more closely involved in the lexical-semantic labelling of remote memories.

Operating Characteristics of the Implicit Learning System Supporting Serial Interception Sequence Learning

ERIC Educational Resources Information Center

Sanchez, Daniel J.; Reber, Paul J.

2012-01-01

The memory system that supports implicit perceptual-motor sequence learning relies on brain regions that operate separately from the explicit, medial temporal lobe memory system. The implicit learning system therefore likely has distinct operating characteristics and information processing constraints. To attempt to identify the limits of the…

Parietal lobe critically supports successful paired immediate and single-item delayed memory for targets.

PubMed

Krumm, Sabine; Kivisaari, Sasa L; Monsch, Andreas U; Reinhardt, Julia; Ulmer, Stephan; Stippich, Christoph; Kressig, Reto W; Taylor, Kirsten I

2017-05-01

The parietal lobe is important for successful recognition memory, but its role is not yet fully understood. We investigated the parietal lobes' contribution to immediate paired-associate memory and delayed item-recognition memory separately for hits (targets) and correct rejections (distractors). We compared the behavioral performance of 56 patients with known parietal and medial temporal lobe dysfunction (i.e. early Alzheimer's Disease) to 56 healthy control participants in an immediate paired and delayed single item object memory task. Additionally, we performed voxel-based morphometry analyses to investigate the functional-neuroanatomic relationships between performance and voxel-based estimates of atrophy in whole-brain analyses. Behaviorally, all participants performed better identifying targets than rejecting distractors. The voxel-based morphometry analyses associated atrophy in the right ventral parietal cortex with fewer correct responses to familiar items (i.e. hits) in the immediate and delayed conditions. Additionally, medial temporal lobe integrity correlated with better performance in rejecting distractors, but not in identifying targets, in the immediate paired-associate task. Our findings suggest that the parietal lobe critically supports successful immediate and delayed target recognition memory, and that the ventral aspect of the parietal cortex and the medial temporal lobe may have complementary preferences for identifying targets and rejecting distractors, respectively, during recognition memory. Copyright © 2017. Published by Elsevier Inc.

Elaboration versus suppression of cued memories: influence of memory recall instruction and success on parietal lobe, default network, and hippocampal activity.

PubMed

Gimbel, Sarah I; Brewer, James B

2014-01-01

Functional imaging studies of episodic memory retrieval consistently report task-evoked and memory-related activity in the medial temporal lobe, default network and parietal lobe subregions. Associated components of memory retrieval, such as attention-shifts, search, retrieval success, and post-retrieval processing also influence regional activity, but these influences remain ill-defined. To better understand how top-down control affects the neural bases of memory retrieval, we examined how regional activity responses were modulated by task goals during recall success or failure. Specifically, activity was examined during memory suppression, recall, and elaborative recall of paired-associates. Parietal lobe was subdivided into dorsal (BA 7), posterior ventral (BA 39), and anterior ventral (BA 40) regions, which were investigated separately to examine hypothesized distinctions in sub-regional functional responses related to differential attention-to-memory and memory strength. Top-down suppression of recall abolished memory strength effects in BA 39, which showed a task-negative response, and BA 40, which showed a task-positive response. The task-negative response in default network showed greater negatively-deflected signal for forgotten pairs when task goals required recall. Hippocampal activity was task-positive and was influenced by memory strength only when task goals required recall. As in previous studies, we show a memory strength effect in parietal lobe and hippocampus, but we show that this effect is top-down controlled and sensitive to whether the subject is trying to suppress or retrieve a memory. These regions are all implicated in memory recall, but their individual activity patterns show distinct memory-strength-related responses when task goals are varied. In parietal lobe, default network, and hippocampus, top-down control can override the commonly identified effects of memory strength.

Elaboration versus Suppression of Cued Memories: Influence of Memory Recall Instruction and Success on Parietal Lobe, Default Network, and Hippocampal Activity

PubMed Central

Gimbel, Sarah I.; Brewer, James B.

2014-01-01

Functional imaging studies of episodic memory retrieval consistently report task-evoked and memory-related activity in the medial temporal lobe, default network and parietal lobe subregions. Associated components of memory retrieval, such as attention-shifts, search, retrieval success, and post-retrieval processing also influence regional activity, but these influences remain ill-defined. To better understand how top-down control affects the neural bases of memory retrieval, we examined how regional activity responses were modulated by task goals during recall success or failure. Specifically, activity was examined during memory suppression, recall, and elaborative recall of paired-associates. Parietal lobe was subdivided into dorsal (BA 7), posterior ventral (BA 39), and anterior ventral (BA 40) regions, which were investigated separately to examine hypothesized distinctions in sub-regional functional responses related to differential attention-to-memory and memory strength. Top-down suppression of recall abolished memory strength effects in BA 39, which showed a task-negative response, and BA 40, which showed a task-positive response. The task-negative response in default network showed greater negatively-deflected signal for forgotten pairs when task goals required recall. Hippocampal activity was task-positive and was influenced by memory strength only when task goals required recall. As in previous studies, we show a memory strength effect in parietal lobe and hippocampus, but we show that this effect is top-down controlled and sensitive to whether the subject is trying to suppress or retrieve a memory. These regions are all implicated in memory recall, but their individual activity patterns show distinct memory-strength-related responses when task goals are varied. In parietal lobe, default network, and hippocampus, top-down control can override the commonly identified effects of memory strength. PMID:24586492

Sex differences in verbal and nonverbal learning before and after temporal lobe epilepsy surgery.

PubMed

Berger, Justus; Oltmanns, Frank; Holtkamp, Martin; Bengner, Thomas

2017-01-01

Women outperform men in a host of episodic memory tasks, yet the neuroanatomical basis for this effect is unclear. It has been suggested that the anterior temporal lobe might be especially relevant for sex differences in memory. In the current study, we investigated whether temporal lobe epilepsy (TLE) has an influence on sex effects in learning and memory and whether women and men with TLE differ in their risk for memory deficits after epilepsy surgery. 177 patients (53 women and 41 men with left TLE, 42 women and 41 men with right TLE) were neuropsychologically tested before and one year after temporal lobe resection. We found that women with TLE had better verbal, but not figural, memory than men with TLE. The female advantage in verbal memory was not affected by temporal lobe resection. The same pattern of results was found in a more homogeneous subsample of 84 patients with only hippocampal sclerosis who were seizure-free after surgery. Our findings challenge the concept that the anterior temporal lobe plays a central role in the verbal memory advantage for women. Copyright © 2016 Elsevier Inc. All rights reserved.

Episodic memory, semantic memory, and amnesia.

PubMed

Squire, L R; Zola, S M

1998-01-01

Episodic memory and semantic memory are two types of declarative memory. There have been two principal views about how this distinction might be reflected in the organization of memory functions in the brain. One view, that episodic memory and semantic memory are both dependent on the integrity of medial temporal lobe and midline diencephalic structures, predicts that amnesic patients with medial temporal lobe/diencephalic damage should be proportionately impaired in both episodic and semantic memory. An alternative view is that the capacity for semantic memory is spared, or partially spared, in amnesia relative to episodic memory ability. This article reviews two kinds of relevant data: 1) case studies where amnesia has occurred early in childhood, before much of an individual's semantic knowledge has been acquired, and 2) experimental studies with amnesic patients of fact and event learning, remembering and knowing, and remote memory. The data provide no compelling support for the view that episodic and semantic memory are affected differently in medial temporal lobe/diencephalic amnesia. However, episodic and semantic memory may be dissociable in those amnesic patients who additionally have severe frontal lobe damage.

Declarative long-term memory and the mesial temporal lobe: Insights from a 5-year postsurgery follow-up study on refractory temporal lobe epilepsy.

PubMed

Salvato, Gerardo; Scarpa, Pina; Francione, Stefano; Mai, Roberto; Tassi, Laura; Scarano, Elisa; Lo Russo, Giorgio; Bottini, Gabriella

2016-11-01

It is largely recognized that the mesial temporal lobe and its substructure support declarative long-term memory (LTM). So far, different theories have been suggested, and the organization of declarative verbal LTM in the brain is still a matter of debate. In the current study, we retrospectively selected 151 right-handed patients with temporal lobe epilepsy with and without hippocampal sclerosis, with a homogeneous (seizure-free) clinical outcome. We analyzed verbal memory performance within a normalized scores context, by means of prose recall and word paired-associate learning tasks. Patients were tested at presurgical baseline, 6months, 2 and 5years after anteromesial temporal lobe surgery, using parallel versions of the neuropsychological tests. Our main finding revealed a key involvement of the left temporal lobe and, in particular, of the left hippocampus in prose recall rather than word paired-associate task. We also confirmed that shorter duration of epilepsy, younger age, and withdrawal of antiepileptic drugs would predict a better memory outcome. When individual memory performance was taken into account, data showed that females affected by left temporal lobe epilepsy for longer duration were more at risk of presenting a clinically pathologic LTM at 5years after surgery. Taken together, these findings shed new light on verbal declarative memory in the mesial temporal lobe and on the behavioral signature of the functional reorganization after the surgical treatment of temporal lobe epilepsy. Copyright © 2016 Elsevier Inc. All rights reserved.

Material-Specific Lateralization of Working Memory in the Medial Temporal Lobe

ERIC Educational Resources Information Center

Wagner, Dylan D.; Sziklas, Viviane; Garver, Krista E.; Jones-Gotman, Marilyn

2009-01-01

Mnemonic deficits in patients with medial temporal lobe (MTL) damage arising from temporal lobe epilepsy (TLE) are traditionally constrained to long-term episodic memory, sparing short-term and working memory (WM). This view of WM as being independent of MTL structures has recently been challenged by a small number of patient and neuroimaging…

Working Memory, Long-Term Memory, and Medial Temporal Lobe Function

ERIC Educational Resources Information Center

Jeneson, Annette; Squire, Larry R.

2012-01-01

Early studies of memory-impaired patients with medial temporal lobe (MTL) damage led to the view that the hippocampus and related MTL structures are involved in the formation of long-term memory and that immediate memory and working memory are independent of these structures. This traditional idea has recently been revisited. Impaired performance…

Structural correlates of impaired working memory in hippocampal sclerosis.

PubMed

Winston, Gavin P; Stretton, Jason; Sidhu, Meneka K; Symms, Mark R; Thompson, Pamela J; Duncan, John S

2013-07-01

Temporal lobe epilepsy (TLE) has been considered to impair long-term memory, whilst not affecting working memory, but recent evidence suggests that working memory is compromised. Functional MRI (fMRI) studies demonstrate that working memory involves a bilateral frontoparietal network the activation of which is disrupted in hippocampal sclerosis (HS). A specific role of the hippocampus to deactivate during working memory has been proposed with this mechanism faulty in patients with HS. Structural correlates of disrupted working memory in HS have not been explored. We studied 54 individuals with medically refractory TLE and unilateral HS (29 left) and 28 healthy controls. Subjects underwent 3T structural MRI, a visuospatial n-back fMRI paradigm and diffusion tensor imaging (DTI). Working memory capacity assessed by three span tasks (digit span backwards, gesture span, motor sequences) was combined with performance in the visuospatial paradigm to give a global working memory measure. Gray and white matter changes were investigated using voxel-based morphometry and voxel-based analysis of DTI, respectively. Individuals with left or right HS performed less well than healthy controls on all measures of working memory. fMRI demonstrated a bilateral frontoparietal network during the working memory task with reduced activation of the right parietal lobe in both patient groups. In left HS, gray matter loss was seen in the ipsilateral hippocampus and parietal lobe, with maintenance of the gray matter volume of the contralateral parietal lobe associated with better performance. White matter integrity within the frontoparietal network, in particular the superior longitudinal fasciculus and cingulum, and the contralateral temporal lobe, was associated with working memory performance. In right HS, gray matter loss was also seen in the ipsilateral hippocampus and parietal lobe. Working memory performance correlated with the gray matter volume of both frontal lobes and white matter integrity within the frontoparietal network and contralateral temporal lobe. Our data provide further evidence that working memory is disrupted in HS and impaired integrity of both gray and white matter is seen in functionally relevant areas. We suggest this forms the structural basis of the impairment of working memory, indicating widespread and functionally significant structural changes in patients with apparently isolated HS. Wiley Periodicals, Inc. © 2013 International League Against Epilepsy.

Structural correlates of impaired working memory in hippocampal sclerosis

PubMed Central

Winston, Gavin P; Stretton, Jason; Sidhu, Meneka K; Symms, Mark R; Thompson, Pamela J; Duncan, John S

2013-01-01

Purpose: Temporal lobe epilepsy (TLE) has been considered to impair long-term memory, whilst not affecting working memory, but recent evidence suggests that working memory is compromised. Functional MRI (fMRI) studies demonstrate that working memory involves a bilateral frontoparietal network the activation of which is disrupted in hippocampal sclerosis (HS). A specific role of the hippocampus to deactivate during working memory has been proposed with this mechanism faulty in patients with HS. Structural correlates of disrupted working memory in HS have not been explored. Methods: We studied 54 individuals with medically refractory TLE and unilateral HS (29 left) and 28 healthy controls. Subjects underwent 3T structural MRI, a visuospatial n-back fMRI paradigm and diffusion tensor imaging (DTI). Working memory capacity assessed by three span tasks (digit span backwards, gesture span, motor sequences) was combined with performance in the visuospatial paradigm to give a global working memory measure. Gray and white matter changes were investigated using voxel-based morphometry and voxel-based analysis of DTI, respectively. Key Findings: Individuals with left or right HS performed less well than healthy controls on all measures of working memory. fMRI demonstrated a bilateral frontoparietal network during the working memory task with reduced activation of the right parietal lobe in both patient groups. In left HS, gray matter loss was seen in the ipsilateral hippocampus and parietal lobe, with maintenance of the gray matter volume of the contralateral parietal lobe associated with better performance. White matter integrity within the frontoparietal network, in particular the superior longitudinal fasciculus and cingulum, and the contralateral temporal lobe, was associated with working memory performance. In right HS, gray matter loss was also seen in the ipsilateral hippocampus and parietal lobe. Working memory performance correlated with the gray matter volume of both frontal lobes and white matter integrity within the frontoparietal network and contralateral temporal lobe. Significance: Our data provide further evidence that working memory is disrupted in HS and impaired integrity of both gray and white matter is seen in functionally relevant areas. We suggest this forms the structural basis of the impairment of working memory, indicating widespread and functionally significant structural changes in patients with apparently isolated HS. PMID:23614459

Capturing the Landauer bound through the application of a detailed Jarzynski equality for entropic memory erasure.

PubMed

Das, Moupriya

2014-12-01

The states of an overdamped Brownian particle confined in a two-dimensional bilobal enclosure are considered to correspond to two binary values: 0 (left lobe) and 1 (right lobe). An ensemble of such particles represents bits of entropic information. An external bias is applied on the particles, equally distributed in two lobes, to drive them to a particular lobe erasing one kind of bit of information. It has been shown that the average work done for the entropic memory erasure process approaches the Landauer bound for a very slow erasure cycle. Furthermore, the detailed Jarzynski equality holds to a very good extent for the erasure protocol, so that the Landauer bound may be calculated irrespective of the time period of the erasure cycle in terms of the effective free-energy change for the process. The detailed Jarzynski equality applied to two subprocesses, namely the transition from entropic memory state 0 to state 1 and the transition from entropic memory state 1 to state 1, connects the work done on the system to the probability to occupy the two states under a time-reversed process. In the entire treatment, the work appears as a boundary effect of the physical confinement of the system not having a conventional potential energy barrier. Finally, an analytical derivation of the detailed and classical Jarzynski equality for Brownian movement in confined space with varying width has been proposed. Our analytical scheme supports the numerical simulations presented in this paper.

Functional organization of the medial temporal lobe memory system following neonatal hippocampal lesion in rhesus monkeys.

PubMed

Chareyron, Loïc J; Banta Lavenex, Pamela; Amaral, David G; Lavenex, Pierre

2017-12-01

Hippocampal damage in adult humans impairs episodic and semantic memory, whereas hippocampal damage early in life impairs episodic memory but leaves semantic learning relatively preserved. We have previously shown a similar behavioral dissociation in nonhuman primates. Hippocampal lesion in adult monkeys prevents allocentric spatial relational learning, whereas spatial learning persists following neonatal lesion. Here, we quantified the number of cells expressing the immediate-early gene c-fos, a marker of neuronal activity, to characterize the functional organization of the medial temporal lobe memory system following neonatal hippocampal lesion. Ninety minutes before brain collection, three control and four adult monkeys with bilateral neonatal hippocampal lesions explored a novel environment to activate brain structures involved in spatial learning. Three other adult monkeys with neonatal hippocampal lesions remained in their housing quarters. In unlesioned monkeys, we found high levels of c-fos expression in the intermediate and caudal regions of the entorhinal cortex, and in the perirhinal, parahippocampal, and retrosplenial cortices. In lesioned monkeys, spatial exploration induced an increase in c-fos expression in the intermediate field of the entorhinal cortex, the perirhinal, parahippocampal, and retrosplenial cortices, but not in the caudal entorhinal cortex. These findings suggest that different regions of the medial temporal lobe memory system may require different types of interaction with the hippocampus in support of memory. The caudal perirhinal cortex, the parahippocampal cortex, and the retrosplenial cortex may contribute to spatial learning in the absence of functional hippocampal circuits, whereas the caudal entorhinal cortex may require hippocampal output to support spatial learning.

Parametric fMRI analysis of visual encoding in the human medial temporal lobe.

PubMed

Rombouts, S A; Scheltens, P; Machielson, W C; Barkhof, F; Hoogenraad, F G; Veltman, D J; Valk, J; Witter, M P

1999-01-01

A number of functional brain imaging studies indicate that the medial temporal lobe system is crucially involved in encoding new information into memory. However, most studies were based on differences in brain activity between encoding of familiar vs. novel stimuli. To further study the underlying cognitive processes, we applied a parametric design of encoding. Seven healthy subjects were instructed to encode complex color pictures into memory. Stimuli were presented in a parametric fashion at different rates, thus representing different loads of encoding. Functional magnetic resonance imaging (fMRI) was used to assess changes in brain activation. To determine the number of pictures successfully stored into memory, recognition scores were determined afterwards. During encoding, brain activation occurred in the medial temporal lobe, comparable to the results obtained by others. Increasing the encoding load resulted in an increase in the number of successfully stored items. This was reflected in a significant increase in brain activation in the left lingual gyrus, in the left and right parahippocampal gyrus, and in the right inferior frontal gyrus. This study shows that fMRI can detect changes in brain activation during variation of one aspect of higher cognitive tasks. Further, it strongly supports the notion that the human medial temporal lobe is involved in encoding novel visual information into memory.

It's all coming back to me now: perception and memory in amnesia.

PubMed

Baxter, Mark G

2012-07-12

Medial temporal lobe (MTL) structures may constitute a representational hierarchy, rather than a dedicated system for memory. Barense et al. (2012) show that intact memory for object features can interfere with perception of complex objects in individuals with MTL amnesia. Copyright © 2012 Elsevier Inc. All rights reserved.

Personal semantic memory: insights from neuropsychological research on amnesia.

PubMed

Grilli, Matthew D; Verfaellie, Mieke

2014-08-01

This paper provides insight into the cognitive and neural mechanisms of personal semantic memory, knowledge that is specific and unique to individuals, by reviewing neuropsychological research on stable amnesia secondary to medial temporal lobe damage. The results reveal that personal semantic memory does not depend on a unitary set of cognitive and neural mechanisms. Findings show that autobiographical fact knowledge reflects an experience-near type of personal semantic memory that relies on the medial temporal lobe for retrieval, albeit less so than personal episodic memory. Additional evidence demonstrates that new autobiographical fact learning likely relies on the medial temporal lobe, but the extent to which remains unclear. Other findings show that retrieval of personal traits/roles and new learning of personal traits/roles and thoughts/beliefs are independent of the medial temporal lobe and thus may represent highly conceptual types of personal semantic memory that are stored in the neocortex. Published by Elsevier Ltd.

Spatial memory for asymmetrical dot locations predicts lateralization among patients with presurgical mesial temporal lobe epilepsy.

PubMed

Brown, Franklin C; Hirsch, Lawrence J; Spencer, Dennis D

2015-11-01

This study examined the ability of an asymmetrical dot location memory test (Brown Location Test, BLT) and two verbal memory tests (Verbal Selective Reminding Test (VSRT) and California Verbal Learning Test, Second Edition (CVLT-II)) to correctly lateralize left (LTLE) or right (RTLE) mesial temporal lobe epilepsy that was confirmed with video-EEG. Subjects consisted of 16 patients with medically refractory RTLE and 13 patients with medically refractory LTLE who were left hemisphere language dominant. Positive predictive values for lateralizing TLE correctly were 87.5% for the BLT, 72.7% for the VSRT, and 80% for the CVLT-II. Binary logistic regression indicated that the BLT alone correctly classified 76.9% of patients with left temporal lobe epilepsy and 87.5% of patients with right temporal lobe epilepsy. Inclusion of the verbal memory tests improved this to 92.3% of patients with left temporal lobe epilepsy and 100% correct classification of patients with right temporal lobe epilepsy. Though of a limited sample size, this study suggests that the BLT alone provides strong laterality information which improves with the addition of verbal memory tests. Copyright © 2015 Elsevier Inc. All rights reserved.

Memory for Faces Dissociates from Memory for Location Following Anterior Temporal Lobectomy

ERIC Educational Resources Information Center

Chiaravalloti, Nancy D.; Glosser, Guila

2004-01-01

It has been suggested that the right and left mesial temporal lobes are specialized for processing different types of information for long-term memory (LTM). Although findings have been consistent in regard to the dominant role of the left mesial temporal lobe (MTL) in verbal memory, the role of the right MTL in non-verbal memory remains…

Requirement of the Combination of Mushroom Body ? Lobe and a/ß Lobes for the Retrieval of Both Aversive and Appetitive Early Memories in "Drosophila"

ERIC Educational Resources Information Center

Xie, Zhiyong; Huang, Cheng; Ci, Bo; Lianzhang, Wang; Zhong, Yi

2013-01-01

Extensive studies of "Drosophila" mushroom body in formation and retrieval of olfactory memories allow us to delineate the functional logic for memory storage and retrieval. Currently, there is a questionable disassociation of circuits for memory storage and retrieval during "Drosophila" olfactory memory processing. Formation…

Preoperative EEG predicts memory and selective cognitive functions after temporal lobe surgery.

PubMed Central

Tuunainen, A; Nousiainen, U; Hurskainen, H; Leinonen, E; Pilke, A; Mervaala, E; Vapalahti, M; Partanen, J; Riekkinen, P

1995-01-01

Preoperative and postoperative cognitive and memory functions, psychiatric outcome, and EEGs were evaluated in 32 epileptic patients who underwent temporal lobe surgery. The presence and location of preoperative slow wave focus in routine EEG predicted memory functions of the non-resected side after surgery. Neuropsychological tests of the function of the frontal lobes also showed improvement. Moreover, psychiatric ratings showed that seizure free patients had significantly less affective symptoms postoperatively than those who were still exhibiting seizures. After temporal lobectomies, successful outcome in postoperative memory functions can be achieved in patients with unilateral slow wave activity in preoperative EEGs. This study suggests a new role for routine EEG in preoperative evaluation of patients with temporal lobe epilepsy. PMID:7608663

Cortico-hippocampal systems involved in memory and cognition: the PMAT framework.

PubMed

Ritchey, Maureen; Libby, Laura A; Ranganath, Charan

2015-01-01

In this chapter, we review evidence that the cortical pathways to the hippocampus appear to extend from two large-scale cortical systems: a posterior medial (PM) system that includes the parahippocampal cortex and retrosplenial cortex, and an anterior temporal (AT) system that includes the perirhinal cortex. This "PMAT" framework accounts for differences in the anatomical and functional connectivity of the medial temporal lobes, which may underpin differences in cognitive function between the systems. The PM and AT systems make distinct contributions to memory and to other cognitive domains, and convergent findings suggest that they are involved in processing information about contexts and items, respectively. In order to support the full complement of memory-guided behavior, the two systems must interact, and the hippocampal and ventromedial prefrontal cortex may serve as sites of integration between the two systems. We conclude that when considering the "connected hippocampus," inquiry should extend beyond the medial temporal lobes to include the large-scale cortical systems of which they are a part. © 2015 Elsevier B.V. All rights reserved.

Medial Temporal Lobe Activity during Source Retrieval Reflects Information Type, Not Memory Strength

ERIC Educational Resources Information Center

Diana, Rachel A.; Yonelinas, Andrew P.; Ranganath, Charan

2010-01-01

The medial temporal lobes (MTLs) are critical for episodic memory but the functions of MTL subregions are controversial. According to memory strength theory, MTL subregions collectively support declarative memory in a graded manner. In contrast, other theories assert that MTL subregions support functionally distinct processes. For instance, one…

Subthalamic stimulation differentially modulates declarative and nondeclarative memory.

PubMed

Hälbig, Thomas D; Gruber, Doreen; Kopp, Ute A; Scherer, Peter; Schneider, Gerd-Helge; Trottenberg, Thomas; Arnold, Guy; Kupsch, Andreas

2004-03-01

Declarative memory has been reported to rely on the medial temporal lobe system, whereas non-declarative memory depends on basal ganglia structures. We investigated the functional role of the subthalamic nucleus (STN), a structure closely connected with the basal ganglia for both types of memory. Via deep brain high frequency stimulation (DBS) we manipulated neural activity of the STN in humans. We found that DBS-STN differentially modulated memory performance: declarative memory was impaired, whereas non-declarative memory was improved in the presence of STN-DBS indicating a specific role of the STN in the activation of memory systems. Copyright 2004 Lippincott Williams & Wilkins

Dissociation between Conceptual and Perceptual Implicit Memory: Evidence from Patients with Frontal and Occipital Lobe Lesions

PubMed Central

Gong, Liang; Wang, JiHua; Yang, XuDong; Feng, Lei; Li, Xiu; Gu, Cui; Wang, MeiHong; Hu, JiaYun; Cheng, Huaidong

2016-01-01

The latest neuroimaging studies about implicit memory (IM) have revealed that different IM types may be processed by different parts of the brain. However, studies have rarely examined what subtypes of IM processes are affected in patients with various brain injuries. Twenty patients with frontal lobe injury, 25 patients with occipital lobe injury, and 29 healthy controls (HC) were recruited for the study. Two subtypes of IM were investigated by using structurally parallel perceptual (picture identification task) and conceptual (category exemplar generation task) IM tests in the three groups, as well as explicit memory (EM) tests. The results indicated that the priming of conceptual IM and EM tasks in patients with frontal lobe injury was poorer than that observed in HC, while perceptual IM was identical between the two groups. By contrast, the priming of perceptual IM in patients with occipital lobe injury was poorer than that in HC, whereas the priming of conceptual IM and EM was similar to that in HC. This double dissociation between perceptual and conceptual IM across the brain areas implies that occipital lobes may participate in perceptual IM, while frontal lobes may be involved in processing conceptual memory. PMID:26793093

Frontal lobe function in temporal lobe epilepsy

PubMed Central

Stretton, J.; Thompson, P.J.

2012-01-01

Summary Temporal lobe epilepsy (TLE) is typically associated with long-term memory dysfunction. The frontal lobes support high-level cognition comprising executive skills and working memory that is vital for daily life functioning. Deficits in these functions have been increasingly reported in TLE. Evidence from both the neuropsychological and neuroimaging literature suggests both executive function and working memory are compromised in the presence of TLE. In relation to executive impairment, particular focus has been paid to set shifting as measured by the Wisconsin Card Sorting Task. Other discrete executive functions such as decision-making and theory of mind also appear vulnerable but have received little attention. With regard to working memory, the medial temporal lobe structures appear have a more critical role, but with emerging evidence of hippocampal dependent and independent processes. The relative role of underlying pathology and seizure spread is likely to have considerable bearing upon the cognitive phenotype and trajectory in TLE. The identification of the nature of frontal lobe dysfunction in TLE thus has important clinical implications for prognosis and surgical management. Longitudinal neuropsychological and neuroimaging studies assessing frontal lobe function in TLE patients pre- and postoperatively will improve our understanding further. PMID:22100147

Neuropsychological deficits in temporal lobe epilepsy: A comprehensive review

PubMed Central

Zhao, Fengqing; Kang, Hai; You, LIbo; Rastogi, Priyanka; Venkatesh, D.; Chandra, Mina

2014-01-01

Temporal lobe epilepsy (TLE) is the most prevalent form of complex partial seizures with temporal lobe origin of electrical abnormality. Studies have shown that recurrent seizures affect all aspects of cognitive functioning, including memory, language, praxis, executive functions, and social judgment, among several others. In this article, we will review these cognitive impairments along with their neuropathological correlates in a comprehensive manner. We will see that neuropsychological deficits are prevalent in TLE. Much of the effort has been laid on memory due to the notion that temporal lobe brain structures involved in TLE play a central role in consolidating information into memory. It seems that damage to the mesial structure of the temporal lobe, particularly the amygdale and hippocampus, has the main role in these memory difficulties and the neurobiological plausibility of the role of the temporal lobe in different aspects of memory. Here, we will cover the sub-domains of working memory and episodic memory deficits. This is we will further proceed to evaluate the evidences of executive function deficits in TLE and will see that set-shifting among other EFs is specifically affected in TLE as is social cognition. Finally, critical components of language related deficits are also found in the form of word-finding difficulties. To conclude, TLE affects several of cognitive function domains, but the etiopathogenesis of all these dysfunctions remain elusive. Further well-designed studies are needed for a better understanding of these disorders. PMID:25506156

Modulation of competing memory systems by distraction.

PubMed

Foerde, Karin; Knowlton, Barbara J; Poldrack, Russell A

2006-08-01

Different forms of learning and memory depend on functionally and anatomically separable neural circuits [Squire, L. R. (1992) Psychol. Rev. 99, 195-231]. Declarative memory relies on a medial temporal lobe system, whereas habit learning relies on the striatum [Cohen, N. J. & Eichenbaum, H. (1993) Memory, Amnesia, and the Hippocampal System (MIT Press, Cambridge, MA)]. How these systems are engaged to optimize learning and behavior is not clear. Here, we present results from functional neuroimaging showing that the presence of a demanding secondary task during learning modulates the degree to which subjects solve a problem using either declarative memory or habit learning. Dual-task conditions did not reduce accuracy but reduced the amount of declarative learning about the task. Medial temporal lobe activity was correlated with task performance and declarative knowledge after learning under single-task conditions, whereas performance was correlated with striatal activity after dual-task learning conditions. These results demonstrate a fundamental difference in these memory systems in their sensitivity to concurrent distraction. The results are consistent with the notion that declarative and habit learning compete to mediate task performance, and they suggest that the presence of distraction can bias this competition. These results have implications for learning in multitask situations, suggesting that, even if distraction does not decrease the overall level of learning, it can result in the acquisition of knowledge that can be applied less flexibly in new situations.

Postencephalitic focal retrograde amnesia after bilateral anterior temporal lobe damage.

PubMed

Tanaka, Y; Miyazawa, Y; Hashimoto, R; Nakano, I; Obayashi, T

1999-07-22

Marked retrograde amnesia with no or almost no anterograde amnesia is rare. Recently, a combination of ventrolateral prefrontal and temporopolar cortical lesions has been suggested as the cause of such isolated or focal retrograde amnesia. It is also assumed that when the right-sided cortical structures are damaged, autobiographical episodic memories are affected. To search for new anatomic substrates for focal retrograde amnesia. We performed extensive neuropsychological tests and obtained detailed neuroimages on a 43-year-old woman who showed a severe, persistent retrograde amnesia but only a limited anterograde amnesia after probable herpes simplex encephalitis. Tests of autobiographical memory revealed that she had a memory loss extending back to her childhood for both semantics and incidents; however, the ability to recall specific episodes appeared much more severely impaired than the ability to recall factual information about her past. The patient also showed profound impairments in recalling public memories; however, her scores improved nearly to a control level on forced-choice recognition memory tasks, although the recall of memories for a decade just before her illness remained mildly impaired. MRI revealed focal pathologies in the temporal poles and the anterior parts of the inferotemporal lobes on both sides, predominantly on the left, with some extension to the anterior parts of the medial temporal lobes. There was additional damage to the left insular cortex and its surrounding structures but no evidence of frontal lobe damage on MRIs or cognitive tests. A profound retrograde amnesia may be produced by damage to the bilateral temporal poles and anterior inferotemporal lobes in the absence of frontal lobe pathologies, and a dense and persistent episodic old memory loss can arise even with a relatively small lesion in the right anterior temporal lobe if it is combined with extensive damage to the left.

The von Restorff effect in amnesia: the contribution of the hippocampal system to novelty-related memory enhancements.

PubMed

Kishiyama, M M; Yonelinas, A P; Lazzara, M M

2004-01-01

The ability to detect novelty is a characteristic of all mammalian nervous systems (Sokolov, 1963), and it plays a critical role in memory in the sense that items that are novel, or distinctive, are remembered better than those that are less distinct (von Restorff, 1933). Although several brain areas are sensitive to stimulus novelty, it is not yet known which regions play a role in producing novelty-related effects on memory. In the current study, we investigated novelty effects on recognition memory in amnesic patients and healthy control subjects. The control subjects demonstrated better recognition for items that were novel (i.e., presented in an infrequent color), and this effect was found for both recollection and familiarity-based responses. However, the novelty advantage was effectively eliminated in patients with extensive medial temporal lobe damage, mild hypoxic patients expected to have relatively selective hippocampal damage, and in a patient with thalamic lesions. The results indicate that the human medial temporal lobes play a critical role in producing normal novelty effects in memory.

Dissecting out conscious and unconscious memory (sub)processes within the human medial temporal lobe.

PubMed

Grunwald, T; Pezer, N; Münte, T F; Kurthen, M; Lehnertz, K; Van Roost, D; Fernández, G; Kutas, M; Elger, C E

2003-11-01

The human medial temporal lobe (MTL) system mediates memories that can be consciously recollected. However, the specific natures of the individual contributions of its various subregions to conscious memory processes remain equivocal. Here we show a functional dissociation between the hippocampus proper and the parahippocampal region in conscious and unconscious memory as revealed by invasive recordings of limbic event-related brain potentials recorded during explicit and implicit word recognition: Only hippocampal and not parahippocampal neural activity exhibits a sensitivity to the implicit versus explicit nature of the recognition memory task. Moreover, only within the hippocampus proper do the neural responses to repeated words differ not only from those to new words but also from each other as a function of recognition success. By contrast parahippocampal (rhinal) responses are sensitive to repetition independent of conscious recognition. These findings thus demonstrate that it is the hippocampus proper among the MTL structures that is specifically engaged during conscious memory processes.

Behavioral profiles in frontal lobe epilepsy: Autobiographic memory versus mood impairment.

PubMed

Rayner, Genevieve; Jackson, Graeme D; Wilson, Sarah J

2015-02-01

Autobiographic memory encompasses the encoding and retrieval of episodes, people, and places encountered in everyday life. It can be impaired in both epilepsy and frontal lobe damage. Here, we performed an initial investigation of how autobiographic memory is impacted by chronic frontal lobe epilepsy (FLE) together with its underlying pathology. We prospectively studied a series of nine consecutive patients with medically refractory FLE, relative to 24 matched healthy controls. Seven of the nine patients had frontal lobe structural abnormalities. Episodic and semantic autobiographic memory functioning was profiled, and factors associated with impaired autobiographic memory were identified among epileptologic, neuroimaging, neuropsychiatric, and cognitive variables including auditory-verbal and visual memory, and the executive function of cognitive control. Results showed that the FLE group experienced significantly higher rates of autobiographic memory and mood disturbance (p < 0.001), with detailed assessment of individual patients revealing two profiles of impairment, primarily characterized by cognitive or mood disturbance. Five of the patients (56%) exhibited significant episodic autobiographic memory deficits, whereas in three of these, knowledge of semantic autobiographic facts was preserved. Four of them also had reduced cognitive control. Mood disorder was largely unrelated to poor autobiographic memory. In contrast, the four cases with preserved autobiographic memory were notable for their past or current depressive symptoms. These findings provide preliminary data that frontal lobe seizure activity with its underlying pathology may selectively disrupt large-scale cognitive or affective networks, giving rise to different neurobehavioral profiles that may be used to inform clinical management. Wiley Periodicals, Inc. © 2015 International League Against Epilepsy.

Determinants of Autobiographical Memory in Patients with Unilateral Temporal Lobe Epilepsy or Excisions

ERIC Educational Resources Information Center

St-Laurent, Marie; Moscovitch, Morris; Levine, Brian; McAndrews, Mary Pat

2009-01-01

Patients with unilateral temporal lobe epilepsy from hippocampal origin and patients with unilateral surgical excision of an epileptic focus located in the medial temporal lobe were compared to healthy controls on a version of the Autobiographical Interview (AI) adapted to assess memory for event-specific and generic personal episodes. For both…

Frontal Lobe Involvement in a Task of Time-Based Prospective Memory

ERIC Educational Resources Information Center

McFarland, Craig P.; Glisky, Elizabeth L.

2009-01-01

Time-based prospective memory (PM) has been found to be negatively affected by aging, possibly as a result of declining frontal lobe (FL) function. Despite a clear retrospective component to PM tasks, the medial temporal lobes (MTL) are thought to play only a secondary role in successful task completion. The present study investigated the role of…

Memory Functions following Surgery for Temporal Lobe Epilepsy in Children

ERIC Educational Resources Information Center

Jambaque, Isabelle; Dellatolas, Georges; Fohlen, Martine; Bulteau, Christine; Watier, Laurence; Dorfmuller, Georg; Chiron, Catherine; Delalande, Olivier

2007-01-01

Surgical treatment appears to improve the cognitive prognosis in children undergoing surgery for temporal lobe epilepsy (TLE). The beneficial effects of surgery on memory functions, particularly on material-specific memory, are more difficult to assess because of potentially interacting factors such as age range, intellectual level,…

Medial Temporal Lobe Memory in Childhood: Developmental Transitions

ERIC Educational Resources Information Center

Townsend, Elise L.; Richmond, Jenny L.; Vogel-Farley, Vanessa K.; Thomas, Kathleen

2010-01-01

The medial temporal lobes (MTL) support declarative memory and mature structurally and functionally during the postnatal years in humans. Although recent work has addressed the development of declarative memory in early childhood, less is known about continued development beyond this period of time. The purpose of this investigation was to explore…

Autobiographical memory of the recent past following frontal cortex or temporal lobe excisions.

PubMed

Thaiss, Laila; Petrides, Michael

2008-08-01

Previous research has raised questions regarding the necessity of the frontal cortex in autobiographical memory and the role that it plays in actively retrieving contextual information associated with personally relevant events. Autobiographical memory was studied in patients with unilateral excisions restricted to the frontal cortex or temporal lobe involving the amygdalo-hippocampal region and in normal controls using an event-sampling method. We examined accuracy of free recall, use of strategies during retrieval and memory for specific aspects of the autobiographical events, including temporal order. Patients with temporal lobe excisions were impaired in autobiographical recall. By contrast, patients with frontal cortical excisions exhibited normal autobiographical recall but were less likely to use temporal order spontaneously to organize event retrieval. Instruction to organize retrieval by temporal order failed to improve recall in temporal lobe patients and increased the incidence of plausible intrusion errors in left temporal patients. In contrast, patients with frontal cortical excisions now surpassed control subjects in recall of autobiographical events. Furthermore, the retrieval accuracy for the temporal order of diary events was not impaired in these patients. In a subsequent cued recall test, temporal lobe patients were impaired in their memory for the details of the diary events and their context. In conclusion, a basic impairment in autobiographical memory (including memory for temporal context) results from damage to the temporal lobe and not the frontal cortex. Patients with frontal excisions fail to use organizational strategies spontaneously to aid retrieval but can use these effectively if instructed to do so.

Lateralized Spatial and Object Memory Encoding in Entorhinal and Perirhinal Cortices

ERIC Educational Resources Information Center

Bellgowan, Patrick S. F.; Buffalo, Elizabeth A.; Bodurka, Jerzy; Martin, Alex

2009-01-01

The perirhinal and entorhinal cortices are critical components of the medial temporal lobe (MTL) declarative memory system. Study of their specific functions using blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI), however, has suffered from severe magnetic susceptibility signal dropout resulting in poor…

From learning to forgetting: behavioral, circuitry, and molecular properties define the different functional states of the recognition memory trace.

PubMed

Romero-Granados, Rocío; Fontán-Lozano, Angela; Delgado-García, José María; Carrión, Angel M

2010-05-01

Neuropsychological analyses of amnesic patients, as well as lesion experiments, indicate that the temporal lobe is essential for the encoding, storage, and expression of object recognition memory (ORM). However, temporal lobe structures directly involved in the consolidation and reconsolidation of these memories are not yet well-defined. We report here that systemic administration of a protein synthesis inhibitor before or up to 4 h after training or reactivation sessions impairs consolidation and reconsolidation of ORM, without affecting short-term memory. We have also observed that ORM reconsolidation is sensitive to protein synthesis inhibition, independently of the ORM trace age. Using bdnf and egr-1 gene expression analysis, we defined temporal lobe areas related to consolidation and reconsolidation of ORM. Training and reactivation 21 days after ORM acquisition sessions provoked changes in bdnf mRNA in somatosensory, perirhinal, and hippocampal cortices. Reactivation 2 days after the training session elicited changes in bdnf and egr-1 mRNA in entorhinal and prefrontal cortices, while reactivation 9 days post-training provoked an increase in egr-1 transcription in somatosensory and entorhinal cortices. The differences in activated circuits and in the capacity to recall the memory trace after 9 or 21 days post-training suggest that memory trace suffers functional changes in this period of time. All these results indicate that the functional state of the recognition memory trace, from acquisition to forgetting, can be specifically defined by behavioral, circuitry, and molecular properties. 2009 Wiley-Liss, Inc.

Differences in visual vs. verbal memory impairments as a result of focal temporal lobe damage in patients with traumatic brain injury.

PubMed

Ariza, Mar; Pueyo, Roser; Junqué, Carme; Mataró, María; Poca, María Antonia; Mena, Maria Pau; Sahuquillo, Juan

2006-09-01

The aim of the present study was to determine whether the type of lesion in a sample of moderate and severe traumatic brain injury (TBI) was related to material-specific memory impairment. Fifty-nine patients with TBI were classified into three groups according to whether the site of the lesion was right temporal, left temporal or diffuse. Six-months post-injury, visual (Warrington's Facial Recognition Memory Test and Rey's Complex Figure Test) and verbal (Rey's Auditory Verbal Learning Test) memories were assessed. Visual memory deficits assessed by facial memory were associated with right temporal lobe lesion, whereas verbal memory performance assessed with a list of words was related to left temporal lobe lesion. The group with diffuse injury showed both verbal and visual memory impairment. These results suggest a material-specific memory impairment in moderate and severe TBI after focal temporal lesions and a non-specific memory impairment after diffuse damage.

The timing of associative memory formation: frontal lobe and anterior medial temporal lobe activity at associative binding predicts memory

PubMed Central

Hales, J. B.

2011-01-01

The process of associating items encountered over time and across variable time delays is fundamental for creating memories in daily life, such as for stories and episodes. Forming associative memory for temporally discontiguous items involves medial temporal lobe structures and additional neocortical processing regions, including prefrontal cortex, parietal lobe, and lateral occipital regions. However, most prior memory studies, using concurrently presented stimuli, have failed to examine the temporal aspect of successful associative memory formation to identify when activity in these brain regions is predictive of associative memory formation. In the current study, functional MRI data were acquired while subjects were shown pairs of sequentially presented visual images with a fixed interitem delay within pairs. This design allowed the entire time course of the trial to be analyzed, starting from onset of the first item, across the 5.5-s delay period, and through offset of the second item. Subjects then completed a postscan recognition test for the items and associations they encoded during the scan and their confidence for each. After controlling for item-memory strength, we isolated brain regions selectively involved in associative encoding. Consistent with prior findings, increased regional activity predicting subsequent associative memory success was found in anterior medial temporal lobe regions of left perirhinal and entorhinal cortices and in left prefrontal cortex and lateral occipital regions. The temporal separation within each pair, however, allowed extension of these findings by isolating the timing of regional involvement, showing that increased response in these regions occurs during binding but not during maintenance. PMID:21248058

Contributions of the Medial Temporal Lobe to Declarative Memory Retrieval: Manipulating the Amount of Contextual Retrieval

ERIC Educational Resources Information Center

Tendolkar, Indira; Arnold, Jennifer; Petersson, Karl Magnus; Weis, Susanne; Brockhaus-Dumke, Anke; van Eijndhoven, Philip; Buitelaar, Jan; Fernandez, Guillen

2008-01-01

We investigated how the hippocampus and its adjacent mediotemporal structures contribute to contextual and noncontextual declarative memory retrieval by manipulating the amount of contextual information across two levels of the same contextual dimension in a source memory task. A first analysis identified medial temporal lobe (MTL) substructures…

Memory, Metamemory and Their Dissociation in Temporal Lobe Epilepsy

ERIC Educational Resources Information Center

Howard, Charlotte E.; Andres, Pilar; Broks, Paul; Noad, Rupert; Sadler, Martin; Coker, Debbie; Mazzoni, Giuliana

2010-01-01

Patients with temporal-lobe epilepsy (TLE) present with memory difficulties. The aim of the current study was to determine to what extent these difficulties could be related to a metamemory impairment. Fifteen patients with TLE and 15 matched healthy controls carried out a paired-associates learning task. Memory recall was measured at intervals of…

Arousal Enhanced Memory Retention Is Eliminated Following Temporal Lobe Resection

ERIC Educational Resources Information Center

Ahs, Fredrik; Kumlien, Eva; Fredrikson, Mats

2010-01-01

The amygdala, situated in the anterior medial temporal lobe (MTL), is involved in the emotional enhancement of memory. The present study evaluated whether anterior MTL-resections attenuated arousal induced memory enhancement for pictures. Also, the effect of MTL-resections on response latencies at retrieval was assessed. Thirty-one patients with…

Associative episodic memory and recollective processes in childhood temporal lobe epilepsy.

PubMed

Martins, Sylvie; Guillery-Girard, Bérengère; Clochon, Patrice; Bulteau, Christine; Hertz-Pannier, Lucie; Chiron, Catherine; Eustache, Francis; Jambaqué, Isabelle

2015-03-01

While the current literature on children suffering from temporal lobe epilepsy (CTLE) mostly focuses on material-related episodic memory deficits according to seizure-onset lateralization, the present study examined associative episodic memory according to the type of information to memorize (e.g., factual, spatial, and sequential) and further investigated subjective and objective recollection. Eleven children with left temporal lobe epilepsy (LTLE), 10 children with right temporal lobe epilepsy (RTLE), among whom 9 displayed hippocampal sclerosis (HS), and 42 healthy controls completed the WHAT-WHEN-WHERE protocol (Guillery-Girard et al., 2013). Group comparisons were first conducted according to the affected side and second according to the underlying pathology. Results showed associative memory impairments in patients irrespective of the affected side. Moreover, this study revealed that HS is particularly deleterious to associative and subjective recollection in CTLE. In addition, this study emphasizes the need for assessing episodic memory in childhood TLE beyond material specificity. Copyright © 2015 Elsevier Inc. All rights reserved.

Systematic Review of Cognitive Function in Euthymic Bipolar Disorder and Pre-Surgical Temporal Lobe Epilepsy.

PubMed

Bostock, Emmanuelle C S; Kirkby, Kenneth C; Garry, Michael I; Taylor, Bruce V M

2017-01-01

Bipolar disorder (BD) and temporal lobe epilepsy (TLE) overlap in domains including epidemiology, treatment response, shared neurotransmitter involvement and temporal lobe pathology. Comparison of cognitive function in both disorders may indicate temporal lobe mediated processes relevant to BD. This systematic review examines neuropsychological test profiles in euthymic bipolar disorder type I (BD-I) and pre-surgical TLE and compares experimental designs used. A search of PubMed, PsychINFO, and Scopus using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was conducted. Inclusion criteria were comparison group or pre- to post-surgical patients; reported neuropsychological tests; participants aged 18-60 years. Fifty six studies met criteria: 27 BD-I; 29 TLE. Deficits in BD-I compared to healthy controls (HC) were in executive function, attention span and verbal memory. Deficits in TLE compared to HC were in executive function and memory. In the pre- to post-surgical comparisons, verbal memory in left temporal lobe (LTL) and, less consistently, visuospatial memory in right temporal lobe (RTL) epilepsy declined following surgery. BD-I studies used comprehensive test batteries in well-defined euthymic patients compared to matched HC groups. TLE studies used convenience samples pre- to post-surgery, comparing LTL and RTL subgroups, few included comparisons to HC (5 studies). TLE studies typically examined a narrow range of known temporal lobe-mediated neuropsychological functions, particularly verbal and visuospatial memory. Both disorders exhibit deficits in executive function and verbal memory suggestive of both frontal and temporal lobe involvement. However, deficits in TLE are measured pre- to post-surgery and not controlled at baseline pre-surgery. Further research involving a head-to-head comparison of the two disorders on a broad range of neuropsychological tests is needed to clarify the nature and extent of cognitive deficits and potential overlaps.

Attention improves memory by suppressing spiking-neuron activity in the human anterior temporal lobe.

PubMed

Wittig, John H; Jang, Anthony I; Cocjin, John B; Inati, Sara K; Zaghloul, Kareem A

2018-06-01

We identify a memory-specific attention mechanism in the human anterior temporal lobe, an area implicated in semantic processing and episodic memory formation. Spiking neuron activity is suppressed and becomes more reliable in preparation for verbal memory formation. Intracranial electroencephalography signals implicate this region as a source of executive control for attentional selection. Consistent with this interpretation, its surgical removal causes significant memory impairment for attended words relative to unattended words.

Thalamic pathology and memory loss in early Alzheimer’s disease: moving the focus from the medial temporal lobe to Papez circuit

PubMed Central

Pralus, Agathe; Nelson, Andrew J. D.; Hornberger, Michael

2016-01-01

Abstract It is widely assumed that incipient protein pathology in the medial temporal lobe instigates the loss of episodic memory in Alzheimer’s disease, one of the earliest cognitive deficits in this type of dementia. Within this region, the hippocampus is seen as the most vital for episodic memory. Consequently, research into the causes of memory loss in Alzheimer’s disease continues to centre on hippocampal dysfunction and how disease-modifying therapies in this region can potentially alleviate memory symptomology. The present review questions this entrenched notion by bringing together findings from post-mortem studies, non-invasive imaging (including studies of presymptomatic, at-risk cases) and genetically modified animal models. The combined evidence indicates that the loss of episodic memory in early Alzheimer’s disease reflects much wider neurodegeneration in an extended mnemonic system (Papez circuit), which critically involves the limbic thalamus. Within this system, the anterior thalamic nuclei are prominent, both for their vital contributions to episodic memory and for how these same nuclei appear vulnerable in prodromal Alzheimer’s disease. As thalamic abnormalities occur in some of the earliest stages of the disease, the idea that such changes are merely secondary to medial temporal lobe dysfunctions is challenged. This alternate view is further strengthened by the interdependent relationship between the anterior thalamic nuclei and retrosplenial cortex, given how dysfunctions in the latter cortical area provide some of the earliest in vivo imaging evidence of prodromal Alzheimer’s disease. Appreciating the importance of the anterior thalamic nuclei for memory and attention provides a more balanced understanding of Alzheimer’s disease. Furthermore, this refocus on the limbic thalamus, as well as the rest of Papez circuit, would have significant implications for the diagnostics, modelling, and experimental treatment of cognitive symptoms in Alzheimer’s disease. PMID:27190025

Contributions of Memory Circuits to Language: The Declarative/Procedural Model

ERIC Educational Resources Information Center

Ullman, Michael T.

2004-01-01

The structure of the brain and the nature of evolution suggest that, despite its uniqueness, language likely depends on brain systems that also subserve other functions. The declarative/procedural (DP) model claims that the mental lexicon of memorized word-specific knowledge depends on the largely temporal-lobe substrates of declarative memory,…

Memory network plasticity after temporal lobe resection: a longitudinal functional imaging study

PubMed Central

Sidhu, Meneka K.; Stretton, Jason; Winston, Gavin P.; McEvoy, Andrew W.; Symms, Mark; Thompson, Pamela J.; Koepp, Matthias J.

2016-01-01

Abstract Anterior temporal lobe resection can control seizures in up to 80% of patients with temporal lobe epilepsy. Memory decrements are the main neurocognitive complication. Preoperative functional reorganization has been described in memory networks, but less is known of postoperative reorganization. We investigated reorganization of memory-encoding networks preoperatively and 3 and 12 months after surgery. We studied 36 patients with unilateral medial temporal lobe epilepsy (19 right) before and 3 and 12 months after anterior temporal lobe resection. Fifteen healthy control subjects were studied at three equivalent time points. All subjects had neuropsychological testing at each of the three time points. A functional magnetic resonance imaging memory-encoding paradigm of words and faces was performed with subsequent out-of-scanner recognition assessments. Changes in activations across the time points in each patient group were compared to changes in the control group in a single flexible factorial analysis. Postoperative change in memory across the time points was correlated with postoperative activations to investigate the efficiency of reorganized networks. Left temporal lobe epilepsy patients showed increased right anterior hippocampal and frontal activation at both 3 and 12 months after surgery relative to preoperatively, for word and face encoding, with a concomitant reduction in left frontal activation 12 months postoperatively. Right anterior hippocampal activation 12 months postoperatively correlated significantly with improved verbal learning in patients with left temporal lobe epilepsy from preoperatively to 12 months postoperatively. Preoperatively, there was significant left posterior hippocampal activation that was sustained 3 months postoperatively at word encoding, and increased at face encoding. For both word and face encoding this was significantly reduced from 3 to 12 months postoperatively. Patients with right temporal lobe epilepsy showed increased left anterior hippocampal activation on word encoding from 3 to 12 months postoperatively compared to preoperatively. On face encoding, left anterior hippocampal activations were present preoperatively and 12 months postoperatively. Left anterior hippocampal and orbitofrontal cortex activations correlated with improvements in both design and verbal learning 12 months postoperatively. On face encoding, there were significantly increased left posterior hippocampal activations that reduced significantly from 3 to 12 months postoperatively. Postoperative changes occur in the memory-encoding network in both left and right temporal lobe epilepsy patients across both verbal and visual domains. Three months after surgery, compensatory posterior hippocampal reorganization that occurs is transient and inefficient. Engagement of the contralateral hippocampus 12 months after surgery represented efficient reorganization in both patient groups, suggesting that the contralateral hippocampus contributes to memory outcome 12 months after surgery. PMID:26754787

Prediction of seizure-onset laterality by using Wada memory asymmetries in pediatric epilepsy surgery candidates.

PubMed

Lee, Gregory P; Park, Yong D; Hempel, Ann; Westerveld, Michael; Loring, David W

2002-09-01

Because the capacity of intracarotid amobarbital (Wada) memory assessment to predict seizure-onset laterality in children has not been thoroughly investigated, three comprehensive epilepsy surgery centers pooled their data and examined Wada memory asymmetries to predict side of seizure onset in children being considered for epilepsy surgery. One hundred fifty-two children with intractable epilepsy underwent Wada testing. Although the type and number of memory stimuli and methods varied at each institution, all children were presented with six to 10 items soon after amobarbital injection. After return to neurologic baseline, recognition memory for the stimuli was assessed. Seizure onset was determined by simultaneous video-EEG recordings of multiple seizures. In children with unilateral temporal lobe seizures (n = 87), Wada memory asymmetries accurately predicted seizure laterality to a statistically significant degree. Wada memory asymmetries also correctly predicted side of seizure onset in children with extra-temporal lobe seizures (n = 65). Although individual patient prediction accuracy was statistically significant in temporal lobe cases, onset laterality was incorrectly predicted in < or =52% of children with left temporal lobe seizure onset, depending on the methods and asymmetry criterion used. There also were significant differences between Wada prediction accuracy across the three epilepsy centers. Results suggest that Wada memory assessment is useful in predicting side of seizure onset in many children. However, Wada memory asymmetries should be interpreted more cautiously in children than in adults.

True memory, false memory, and subjective recollection deficits after focal parietal lobe lesions.

PubMed

Drowos, David B; Berryhill, Marian; André, Jessica M; Olson, Ingrid R

2010-07-01

There is mounting evidence that the posterior parietal cortex (PPC) plays an important role in episodic memory. We previously found that patients with PPC damage exhibit retrieval-related episodic memory deficits. Here we assess whether parietal lobe damage affects episodic memory on a different task: the Deese-Roediger-McDermott (DRM) false-memory paradigm. Two patients with bilateral PPC damage and a group of matched controls were tested. In Experiment 1, the task was to remember words; in Experiment 2 the task was to remember pictures of common objects. Prior studies have shown that normal participants have high levels of false memory to words, low levels to pictures. The patients exhibited significantly lower levels of false memory to words. One patient showed significantly elevated levels of false memory to pictures. The patients' false memories were accompanied by reduced levels of recollection, as tested by a Remember/Know procedure. PPC damage causes decreased levels of false memories and an abnormal Remember/Know profile. Their false memory rate is similar to the rate exhibited by patients with medial temporal lobe damage. These results support the view that portions of the PPC play a critical role in objective and subjective aspects of recollection.

Dissociation between memory accuracy and memory confidence following bilateral parietal lesions.

PubMed

Simons, Jon S; Peers, Polly V; Mazuz, Yonatan S; Berryhill, Marian E; Olson, Ingrid R

2010-02-01

Numerous functional neuroimaging studies have observed lateral parietal lobe activation during memory tasks: a surprise to clinicians who have traditionally associated the parietal lobe with spatial attention rather than memory. Recent neuropsychological studies examining episodic recollection after parietal lobe lesions have reported differing results. Performance was preserved in unilateral lesion patients on source memory tasks involving recollecting the context in which stimuli were encountered, and impaired in patients with bilateral parietal lesions on tasks assessing free recall of autobiographical memories. Here, we investigated a number of possible accounts for these differing results. In 3 experiments, patients with bilateral parietal lesions performed as well as controls at source recollection, confirming the previous unilateral lesion results and arguing against an explanation for those results in terms of contralesional compensation. Reducing the behavioral relevance of mnemonic information critical to the source recollection task did not affect performance of the bilateral lesion patients, indicating that the previously observed reduced autobiographical free recall might not be due to impaired bottom-up attention. The bilateral patients did, however, exhibit reduced confidence in their source recollection abilities across the 3 experiments, consistent with a suggestion that parietal lobe lesions might lead to impaired subjective experience of rich episodic recollection.

Explicit memory and implicit memory in occipital lobe stroke patients.

PubMed

Gong, Liang; Wang, JiHua; Feng, Lei; Wang, MeiHong; Li, Xiu; Hu, JiaYun; Wang, Kai

2015-03-01

Occipital stroke patients mainly showed cortical blindness and unilateral vision loss; memory is generally reserved. Recent reports from neuroimaging show the occipital lobe may be involved in the processing of implicit memory (IM), especially the perception type of IM processing. In this study, we explored the explicit memory (EM) and IM damage in occipital lobe stroke patients. A total of 25 occipital strokes and 29 years of age, educational level equivalent healthy controls (HCs), evaluated by using immediate recall, delayed recall, recognition for EM tasks, picture identification, and category exemplar generation for IM tasks. There was no significant difference between occipital stroke patients and HCs in EM tasks and category exemplar generation task. In the picture identification task, occipital lobe stroke group score was poorer than HC group, the results were statistically significant, but in the pictures identify rate, occipital stroke patients and normal control group had no significant difference. The occipital stroke patients may have IM damage, primarily damage the perception type of IM priming effects, which was unrelated with their cortical blindness. Copyright © 2015 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Semantic memory is impaired in patients with unilateral anterior temporal lobe resection for temporal lobe epilepsy.

PubMed

Lambon Ralph, Matthew A; Ehsan, Sheeba; Baker, Gus A; Rogers, Timothy T

2012-01-01

Contemporary clinical and basic neuroscience studies have increasingly implicated the anterior temporal lobe regions, bilaterally, in the formation of coherent concepts. Mounting convergent evidence for the importance of the anterior temporal lobe in semantic memory is found in patients with bilateral anterior temporal lobe damage (e.g. semantic dementia), functional neuroimaging and repetitive transcranial magnetic stimulation studies. If this proposal is correct, then one might expect patients with anterior temporal lobe resection for long-standing temporal lobe epilepsy to be semantically impaired. Such patients, however, do not present clinically with striking comprehension deficits but with amnesia and variable anomia, leading some to conclude that semantic memory is intact in resection for temporal lobe epilepsy and thus casting doubt over the conclusions drawn from semantic dementia and linked basic neuroscience studies. Whilst there is a considerable neuropsychological literature on temporal lobe epilepsy, few studies have probed semantic memory directly, with mixed results, and none have undertaken the same type of systematic investigation of semantic processing that has been conducted with other patient groups. In this study, therefore, we investigated the semantic performance of 20 patients with resection for chronic temporal lobe epilepsy with a full battery of semantic assessments, including more sensitive measures of semantic processing. The results provide a bridge between the current clinical observations about resection for temporal lobe epilepsy and the expectations from semantic dementia and other neuroscience findings. Specifically, we found that on simple semantic tasks, the patients' accuracy fell in the normal range, with the exception that some patients with left resection for temporal lobe epilepsy had measurable anomia. Once the semantic assessments were made more challenging, by probing specific-level concepts, lower frequency/more abstract items or measuring reaction times on semantic tasks versus those on difficulty-matched non-semantic assessments, evidence of a semantic impairment was found in all individuals. We conclude by describing a unified, computationally inspired framework for capturing the variable degrees of semantic impairment found across different patient groups (semantic dementia, temporal lobe epilepsy, glioma and stroke) as well as semantic processing in neurologically intact participants.

Semantic memory is impaired in patients with unilateral anterior temporal lobe resection for temporal lobe epilepsy

PubMed Central

Ehsan, Sheeba; Baker, Gus A.; Rogers, Timothy T.

2012-01-01

Contemporary clinical and basic neuroscience studies have increasingly implicated the anterior temporal lobe regions, bilaterally, in the formation of coherent concepts. Mounting convergent evidence for the importance of the anterior temporal lobe in semantic memory is found in patients with bilateral anterior temporal lobe damage (e.g. semantic dementia), functional neuroimaging and repetitive transcranial magnetic stimulation studies. If this proposal is correct, then one might expect patients with anterior temporal lobe resection for long-standing temporal lobe epilepsy to be semantically impaired. Such patients, however, do not present clinically with striking comprehension deficits but with amnesia and variable anomia, leading some to conclude that semantic memory is intact in resection for temporal lobe epilepsy and thus casting doubt over the conclusions drawn from semantic dementia and linked basic neuroscience studies. Whilst there is a considerable neuropsychological literature on temporal lobe epilepsy, few studies have probed semantic memory directly, with mixed results, and none have undertaken the same type of systematic investigation of semantic processing that has been conducted with other patient groups. In this study, therefore, we investigated the semantic performance of 20 patients with resection for chronic temporal lobe epilepsy with a full battery of semantic assessments, including more sensitive measures of semantic processing. The results provide a bridge between the current clinical observations about resection for temporal lobe epilepsy and the expectations from semantic dementia and other neuroscience findings. Specifically, we found that on simple semantic tasks, the patients’ accuracy fell in the normal range, with the exception that some patients with left resection for temporal lobe epilepsy had measurable anomia. Once the semantic assessments were made more challenging, by probing specific-level concepts, lower frequency/more abstract items or measuring reaction times on semantic tasks versus those on difficulty-matched non-semantic assessments, evidence of a semantic impairment was found in all individuals. We conclude by describing a unified, computationally inspired framework for capturing the variable degrees of semantic impairment found across different patient groups (semantic dementia, temporal lobe epilepsy, glioma and stroke) as well as semantic processing in neurologically intact participants. PMID:22287382

Contribution of frontal and temporal lobe function to memory interference from divided attention at retrieval.

PubMed

Fernandes, Myra A; Davidson, Patrick S R; Glisky, Elizabeth L; Moscovitch, Morris

2004-07-01

On the basis of their scores on composite measures of frontal and temporal lobe function, derived from neuropsychological testing, seniors were divided preexperimentally into 4 groups. Participants studied a list of unrelated words under full attention and recalled them while concurrently performing an animacy decision task to words, an odd-digit identification task to numbers, or no distracting task. Large interference effects on memory were produced by the animacy but not by the odd-digit distracting task, and this pattern was not influenced by level of frontal or temporal lobe function. Results show associative retrieval is largely disrupted by competition for common representations, and it is not affected by a reduction in general processing resources, attentional capacity, or competition for memory structures in the temporal lobe.

Working memory for conjunctions relies on the medial temporal lobe.

PubMed

Olson, Ingrid R; Page, Katie; Moore, Katherine Sledge; Chatterjee, Anjan; Verfaellie, Mieke

2006-04-26

A prominent theory of hippocampal function proposes that the hippocampus is importantly involved in relating or binding together separate pieces of information to form an episodic representation. This hypothesis has only been applied to studies of long-term memory because the paradigmatic view of the hippocampus is that it is not critical for short-term forms of memory. However, relational processing is important in many working memory tasks, especially tasks using visual stimuli. Here, we test the hypothesis that the medial temporal lobes are important for relational memory even over short delays. The task required patients with medial temporal lobe amnesia and controls to remember three objects, locations, or object-location conjunctions over 1 or 8 s delays. The results show that working memory for objects and locations was at normal levels, but that memory for conjunctions was severely impaired at 8 s delays. Additional analyses suggest that the hippocampus per se is critical for accurate conjunction working memory. We propose that the hippocampus is critically involved in memory for conjunctions at both short and long delays.

Working Memory for Conjunctions Relies on the Medial Temporal Lobe

PubMed Central

Olson, Ingrid R.; Page, Katie; Moore, Katherine Sledge; Chatterjee, Anjan; Verfaellie, Mieke

2006-01-01

A prominent theory of hippocampal function proposes that the hippocampus is importantly involved in relating or binding together separate pieces of information to form an episodic representation. This hypothesis has only been applied to studies of long-term memory because the paradigmatic view of the hippocampus is that it is not critical for short-term forms of memory. However, relational processing is important in many working memory tasks, especially tasks using visual stimuli. Here, we test the hypothesis that the medial temporal lobes are important for relational memory even over short delays. The task required patients with medial temporal lobe amnesia and controls to remember three objects, locations, or object-location conjunctions over 1 or 8 s delays. The results show that working memory for objects and locations was at normal levels, but that memory for conjunctions was severely impaired at 8 s delays. Additional analyses suggest that the hippocampus per se is critical for accurate conjunction working memory. We propose that the hippocampus is critically involved in memory for conjunctions at both short and long delays. PMID:16641239

Studies of Implicit Prototype Extraction in Patients with Mild Cognitive Impairment and Early Alzheimer's Disease

ERIC Educational Resources Information Center

Nosofsky, Robert M.; Denton, Stephen E.; Zaki, Safa R.; Murphy-Knudsen, Anne F.; Unverzagt, Frederick W.

2012-01-01

Studies of incidental category learning support the hypothesis of an implicit prototype-extraction system that is distinct from explicit memory (Smith, 2008). In those studies, patients with explicit-memory impairments due to damage to the medial-temporal lobe performed normally in implicit categorization tasks (Bozoki, Grossman, & Smith, 2006;…

Route Learning Impairment in Temporal Lobe Epilepsy

PubMed Central

Bell, Brian D.

2012-01-01

Memory impairment on neuropsychological tests is relatively common in temporal lobe epilepsy (TLE) patients. But memory rarely has been evaluated in more naturalistic settings. This study assessed TLE (n = 19) and control (n = 32) groups on a real-world route learning (RL) test. Compared to the controls, the TLE group committed significantly more total errors across the three RL test trials. RL errors correlated significantly with standardized auditory and visual memory and visual-perceptual test scores in the TLE group. In the TLE subset for whom hippocampal data were available (n = 14), RL errors also correlated significantly with left hippocampal volume. This is one of the first studies to demonstrate real-world memory impairment in TLE patients and its association with both mesial temporal lobe integrity and standardized memory test performance. The results support the ecological validity of clinical neuropsychological assessment. PMID:23041173

The effect of white matter hyperintensities on verbal memory: Mediation by temporal lobe atrophy.

PubMed

Swardfager, Walter; Cogo-Moreira, Hugo; Masellis, Mario; Ramirez, Joel; Herrmann, Nathan; Edwards, Jodi D; Saleem, Mahwesh; Chan, Parco; Yu, Di; Nestor, Sean M; Scott, Christopher J M; Holmes, Melissa F; Sahlas, Demetrios J; Kiss, Alexander; Oh, Paul I; Strother, Stephen C; Gao, Fuqiang; Stefanovic, Bojana; Keith, Julia; Symons, Sean; Swartz, Richard H; Lanctôt, Krista L; Stuss, Donald T; Black, Sandra E

2018-02-20

To determine the relationship between white matter hyperintensities (WMH) presumed to indicate disease of the cerebral small vessels, temporal lobe atrophy, and verbal memory deficits in Alzheimer disease (AD) and other dementias. We recruited groups of participants with and without AD, including strata with extensive WMH and minimal WMH, into a cross-sectional proof-of-principle study (n = 118). A consecutive case series from a memory clinic was used as an independent validation sample (n = 702; Sunnybrook Dementia Study; NCT01800214). We assessed WMH volume and left temporal lobe atrophy (measured as the brain parenchymal fraction) using structural MRI and verbal memory using the California Verbal Learning Test. Using path modeling with an inferential bootstrapping procedure, we tested an indirect effect of WMH on verbal recall that depends sequentially on temporal lobe atrophy and verbal learning. In both samples, WMH predicted poorer verbal recall, specifically due to temporal lobe atrophy and poorer verbal learning (proof-of-principle -1.53, 95% bootstrap confidence interval [CI] -2.45 to -0.88; and confirmation -0.66, 95% CI [-0.95 to -0.41] words). This pathway was significant in subgroups with (-0.20, 95% CI [-0.38 to -0.07] words, n = 363) and without (-0.71, 95% CI [-1.12 to -0.37] words, n = 339) AD. Via the identical pathway, WMH contributed to deficits in recognition memory (-1.82%, 95% CI [-2.64% to -1.11%]), a sensitive and specific sign of AD. Across dementia syndromes, WMH contribute indirectly to verbal memory deficits considered pathognomonic of Alzheimer disease, specifically by contributing to temporal lobe atrophy. © 2018 American Academy of Neurology.

Verbal memory outcome in patients with normal preoperative verbal memory and left mesial temporal sclerosis.

PubMed

LoGalbo, Anthony; Sawrie, Stephen; Roth, David L; Kuzniecky, Ruben; Knowlton, Robert; Faught, Edward; Martin, Roy

2005-05-01

Previous studies have shown that structural integrity (i.e., presence/absence of mesial temporal sclerosis (MTS)) of the left mesial temporal lobe is associated with verbal memory outcome following left anterior temporal lobectomy (ATL). However, the functional integrity of the left temporal lobe, as exemplified by preoperative verbal memory performance, has also been associated with verbal memory outcome following surgery. We investigated the risk of verbal memory loss in patients with known structural abnormality (i.e., left mesial temporal sclerosis by MRI) and normal preoperative verbal memory performance who undergo left ATL. Seventeen patients with left temporal lobe epilepsy, MRI-based exclusive left MTS, and normal preoperative verbal memory were identified. Normal verbal memory was defined as performance on both Acquisition (learning across trials 1-5) and Retrieval (long delayed free recall) portions of the California Verbal Learning Test (CVLT) above a T score of 40 (>16%ile). Postoperative verbal memory outcome was established by incorporating standardized regression-based (SRB) change scores. Postoperative declines across both CVLT Retrieval T scores and Acquisition T scores (average 20% and average 15% declines from baseline scores, respectively) were measured for the group. The average CVLT Retrieval SRB change score was -2.5, and the average CVLT Acquisition SRB change score was -1.0. A larger proportion of patients demonstrated postoperative declines on Retrieval scores than Acquisition scores (64.7% vs 17.6%, respectively). Even in the presence of left MTS, patients exhibiting normal presurgical verbal memory are at risk for verbal memory declines following ATL. These results suggest that the functional integrity of the left mesial temporal lobe may play an important role in the verbal memory outcome in this patient group.

Memory loss and memory reorganization patterns in temporal lobe epilepsy patients undergoing anterior temporal lobe resection, as demonstrated by pre-versus post-operative functional MRI.

PubMed

Limotai, Chusak; McLachlan, Richard S; Hayman-Abello, Susan; Hayman-Abello, Brent; Brown, Suzan; Bihari, Frank; Mirsattari, Seyed M

2018-06-19

This study was aimed to longitudinally assess memory function and whole-brain memory circuit reorganization in patients with temporal lobe epilepsy (TLE) by comparing activation potentials before versus after anterior temporal lobe (ATL) resection. Nineteen patients with medically-intractable TLE (10 left TLE, 9 right TLE) and 15 healthy controls were enrolled. Group analyses were conducted pre- and post-ATL of a novelty complex scene-encoding paradigm comparing areas of blood oxygen-level-dependent (BOLD) signal activations on functional magnetic resonance imaging (fMRI). None of the pre-operative patient characteristics we studied predicted the extent of pre- to post-operative memory loss. On fMRI, extra-temporal activations were detected pre-operatively in both LTLE and RTLE, particularly in the frontal lobe. Greater activations also were noted in the contralateral hippocampus and parahippocampus in both groups. Performing within-subject comparisons, post-op relative to pre-op, pronounced ipsilateral activations were identified in the left parahippocampal gyrus in LTLE, versus the right middle temporal gyrus in RTLE patients. Memory function was impaired pre-operatively but declined after ATL resection in both RTLE and LTLE patients. Post-operative fMRI results indicate possible functional adaptations to ATL loss, primarily occurring within the left parahippocampal gyrus versus right middle temporal gyrus in LTLE versus RTLE patients, respectively. Copyright © 2018 Elsevier Ltd. All rights reserved.

Episodic Memory and Regional Atrophy in Frontotemporal Lobar Degeneration

PubMed Central

Söderlund, Hedvig; Black, Sandra E.; Miller, Bruce L.; Freedman, Morris; Levine, Brian

2008-01-01

It has been unclear to what extent memory is affected in frontotemporal lobar degeneration (FTLD). Since patients usually have atrophy in regions implicated in memory function, the frontal and/or temporal lobes, one would expect some memory impairment, and that the degree of atrophy in these regions would be inversely related to memory function. The purposes of this study were 1) to assess episodic memory function in FTLD, and more specifically patients' ability to episodically re-experience an event, and determine its source; 2) to examine whether memory performance is related to quantified regional brain atrophy. FTLD patients (n=18) and healthy comparison subjects (n=14) were assessed with cued recall, recognition, “remember/know” (self-reported re-experiencing) and source recall, at 30 min and 24 hr after encoding. Regional gray matter volumes were assessed with high resolution structural MRI concurrently to testing. Patients performed worse than comparison subjects on all memory measures. Gray matter volume in the left medial temporal lobe was positively correlated with recognition, re-experiencing, and source recall. Gray matter volume in the left posterior temporal lobe correlated significantly with recognition, at 30 min and 24 hr, and with source recall at 30 min. Estimated familiarity at 30 min was positively correlated with gray matter volume in the left inferior parietal lobe. In summary, episodic memory deficits in FTLD may be more common than previously thought, particularly in patients with left medial and posterior temporal atrophy. PMID:17888461

The neurobiology of cognitive disorders in temporal lobe epilepsy

PubMed Central

Bell, Brian; Lin, Jack J.; Seidenberg, Michael; Hermann, Bruce

2013-01-01

Cognitive impairment and especially memory disruption is a major complicating feature of the epilepsies. In this review we begin with a focus on the problem of memory impairment in temporal lobe epilepsy. We start with a brief overview of the early development of knowledge regarding the anatomic substrates of memory disorder in temporal lobe epilepsy, followed by discussion of the refinement of that knowledge over time as informed by the outcomes of epilepsy surgery (anterior temporal lobectomy) and the clinical efforts to predict those patients at greatest risk of adverse cognitive outcomes following epilepsy surgery. These efforts also yielded new theoretical insights regarding the function of the human hippocampus and a few examples of these insights are touched on briefly. Finally, the vastly changing view of temporal lobe epilepsy is examined including findings demonstrating that anatomic abnormalities extend far outside the temporal lobe, cognitive impairments extend beyond memory function, with linkage of these distributed cognitive and anatomic abnormalities pointing to a new understanding of the anatomic architecture of cognitive impairment in epilepsy. Challenges remain in understanding the origin of these cognitive and anatomic abnormalities, their progression over time, and most importantly, how to intervene to protect cognitive and brain health in epilepsy. PMID:21304484

Cognitive changes in people with temporal lobe epilepsy over a 13-year period.

PubMed

Mameniškienė, Rūta; Rimšienė, Justė; Puronaitė, Roma

2016-10-01

The aims of our study were to evaluate cognitive decline in people with temporal lobe epilepsy over a period of 13years and to determine what clinical and treatment characteristics may have been associated with these. Thirty-three individuals with temporal lobe epilepsy underwent the same neuropsychological assessment of verbal and nonverbal memory, attention, and executive functions using the same cognitive test battery as one used 13years ago. Long-term verbal and nonverbal memory was tested four weeks later. Results were compared with those carried out 13years earlier. There was no significant change in verbal and verbal-logical memory tests; however, nonverbal memory worsened significantly. Long-term verbal memory declined for 21.9% of participants, long-term verbal-logical memory for 34.4%, and long-term nonverbal memory for 56.3%. Worsening of working verbal and verbal-logical memory was associated with longer epilepsy duration and lower levels of patients' education; worsening of verbal delayed recall and long-term verbal-logical memory was associated with higher seizure frequency. Decline in long-term nonverbal memory had significant association with a longer duration of epilepsy. The worsening of reaction and attention inversely correlated with the symptoms of depression. Over a 13-year period, cognitive functions did not change significantly. Good seizure control and reduced symptoms of depression in this sample of people with temporal lobe epilepsy were associated with better cognitive functioning. The predictors of change of cognitive functions could be complex and require further study. Copyright © 2016 Elsevier Inc. All rights reserved.

Memory assessment in patients with temporal lobe epilepsy to predict memory impairment after surgery: A systematic review.

PubMed

Parra-Díaz, P; García-Casares, N

2017-04-19

Given that surgical treatment of refractory mesial temporal lobe epilepsy may cause memory impairment, determining which patients are eligible for surgery is essential. However, there is little agreement on which presurgical memory assessment methods are best able to predict memory outcome after surgery and identify those patients with a greater risk of surgery-induced memory decline. We conducted a systematic literature review to determine which presurgical memory assessment methods best predict memory outcome. The literature search of PubMed gathered articles published between January 2005 and December 2015 addressing pre- and postsurgical memory assessment in mesial temporal lobe epilepsy patients by means of neuropsychological testing, functional MRI, and other neuroimaging techniques. We obtained 178 articles, 31 of which were included in our review. Most of the studies used neuropsychological tests and fMRI; these methods are considered to have the greatest predictive ability for memory impairment. Other less frequently used techniques included the Wada test and FDG-PET. Current evidence supports performing a presurgical assessment of memory function using both neuropsychological tests and functional MRI to predict memory outcome after surgery. Copyright © 2017 Sociedad Española de Neurología. Publicado por Elsevier España, S.L.U. All rights reserved.

Learning and memory functions of the Basal Ganglia.

PubMed

Packard, Mark G; Knowlton, Barbara J

2002-01-01

Although the mammalian basal ganglia have long been implicated in motor behavior, it is generally recognized that the behavioral functions of this subcortical group of structures are not exclusively motoric in nature. Extensive evidence now indicates a role for the basal ganglia, in particular the dorsal striatum, in learning and memory. One prominent hypothesis is that this brain region mediates a form of learning in which stimulus-response (S-R) associations or habits are incrementally acquired. Support for this hypothesis is provided by numerous neurobehavioral studies in different mammalian species, including rats, monkeys, and humans. In rats and monkeys, localized brain lesion and pharmacological approaches have been used to examine the role of the basal ganglia in S-R learning. In humans, study of patients with neurodegenerative diseases that compromise the basal ganglia, as well as research using brain neuroimaging techniques, also provide evidence of a role for the basal ganglia in habit learning. Several of these studies have dissociated the role of the basal ganglia in S-R learning from those of a cognitive or declarative medial temporal lobe memory system that includes the hippocampus as a primary component. Evidence suggests that during learning, basal ganglia and medial temporal lobe memory systems are activated simultaneously and that in some learning situations competitive interference exists between these two systems.

Dissociation of Short- and Long-Term Face Memory: Evidence from Long-Term Recency Effects in Temporal Lobe Epilepsy

ERIC Educational Resources Information Center

Bengner, T.; Malina, T.

2007-01-01

We tested whether memory deficits in temporal lobe epilepsy (TLE) are better described by a single- or dual-store memory model. To this aim, we analyzed the influence of TLE and proactive interference (PI) on immediate and 24-h long-term recency effects during face recognition in 16 healthy participants and 18 right and 21 left non-surgical TLE…

Implications of Animal Object Memory Research for Human Amnesia

ERIC Educational Resources Information Center

Winters, Boyer D.; Saksida, Lisa M.; Bussey, Timothy J.

2010-01-01

Damage to structures in the human medial temporal lobe causes severe memory impairment. Animal object recognition tests gained prominence from attempts to model "global" human medial temporal lobe amnesia, such as that observed in patient HM. These tasks, such as delayed nonmatching-to-sample and spontaneous object recognition, for assessing…

Weighing the value of memory loss in the surgical evaluation of left temporal lobe epilepsy: A decision analysis

PubMed Central

Akama-Garren, Elliot H.; Bianchi, Matt T.; Leveroni, Catherine; Cole, Andrew J.; Cash, Sydney S.; Westover, M. Brandon

2016-01-01

SUMMARY Objectives Anterior temporal lobectomy is curative for many patients with disabling medically refractory temporal lobe epilepsy, but carries an inherent risk of disabling verbal memory loss. Although accurate prediction of iatrogenic memory loss is becoming increasingly possible, it remains unclear how much weight such predictions should have in surgical decision making. Here we aim to create a framework that facilitates a systematic and integrated assessment of the relative risks and benefits of surgery versus medical management for patients with left temporal lobe epilepsy. Methods We constructed a Markov decision model to evaluate the probabilistic outcomes and associated health utilities associated with choosing to undergo a left anterior temporal lobectomy versus continuing with medical management for patients with medically refractory left temporal lobe epilepsy. Three base-cases were considered, representing a spectrum of surgical candidates encountered in practice, with varying degrees of epilepsy-related disability and potential for decreased quality of life in response to post-surgical verbal memory deficits. Results For patients with moderately severe seizures and moderate risk of verbal memory loss, medical management was the preferred decision, with increased quality-adjusted life expectancy. However, the preferred choice was sensitive to clinically meaningful changes in several parameters, including quality of life impact of verbal memory decline, quality of life with seizures, mortality rate with medical management, probability of remission following surgery, and probability of remission with medical management. Significance Our decision model suggests that for patients with left temporal lobe epilepsy, quantitative assessment of risk and benefit should guide recommendation of therapy. In particular, risk for and potential impact of verbal memory decline should be carefully weighed against the degree of disability conferred by continued seizures on a patient-by-patient basis. PMID:25244498

Weighing the value of memory loss in the surgical evaluation of left temporal lobe epilepsy: a decision analysis.

PubMed

Akama-Garren, Elliot H; Bianchi, Matt T; Leveroni, Catherine; Cole, Andrew J; Cash, Sydney S; Westover, M Brandon

2014-11-01

Anterior temporal lobectomy is curative for many patients with disabling medically refractory temporal lobe epilepsy, but carries an inherent risk of disabling verbal memory loss. Although accurate prediction of iatrogenic memory loss is becoming increasingly possible, it remains unclear how much weight such predictions should have in surgical decision making. Here we aim to create a framework that facilitates a systematic and integrated assessment of the relative risks and benefits of surgery versus medical management for patients with left temporal lobe epilepsy. We constructed a Markov decision model to evaluate the probabilistic outcomes and associated health utilities associated with choosing to undergo a left anterior temporal lobectomy versus continuing with medical management for patients with medically refractory left temporal lobe epilepsy. Three base-cases were considered, representing a spectrum of surgical candidates encountered in practice, with varying degrees of epilepsy-related disability and potential for decreased quality of life in response to post-surgical verbal memory deficits. For patients with moderately severe seizures and moderate risk of verbal memory loss, medical management was the preferred decision, with increased quality-adjusted life expectancy. However, the preferred choice was sensitive to clinically meaningful changes in several parameters, including quality of life impact of verbal memory decline, quality of life with seizures, mortality rate with medical management, probability of remission following surgery, and probability of remission with medical management. Our decision model suggests that for patients with left temporal lobe epilepsy, quantitative assessment of risk and benefit should guide recommendation of therapy. In particular, risk for and potential impact of verbal memory decline should be carefully weighed against the degree of disability conferred by continued seizures on a patient-by-patient basis. Wiley Periodicals, Inc. © 2014 International League Against Epilepsy.

Auditory connections and functions of prefrontal cortex

PubMed Central

Plakke, Bethany; Romanski, Lizabeth M.

2014-01-01

The functional auditory system extends from the ears to the frontal lobes with successively more complex functions occurring as one ascends the hierarchy of the nervous system. Several areas of the frontal lobe receive afferents from both early and late auditory processing regions within the temporal lobe. Afferents from the early part of the cortical auditory system, the auditory belt cortex, which are presumed to carry information regarding auditory features of sounds, project to only a few prefrontal regions and are most dense in the ventrolateral prefrontal cortex (VLPFC). In contrast, projections from the parabelt and the rostral superior temporal gyrus (STG) most likely convey more complex information and target a larger, widespread region of the prefrontal cortex. Neuronal responses reflect these anatomical projections as some prefrontal neurons exhibit responses to features in acoustic stimuli, while other neurons display task-related responses. For example, recording studies in non-human primates indicate that VLPFC is responsive to complex sounds including vocalizations and that VLPFC neurons in area 12/47 respond to sounds with similar acoustic morphology. In contrast, neuronal responses during auditory working memory involve a wider region of the prefrontal cortex. In humans, the frontal lobe is involved in auditory detection, discrimination, and working memory. Past research suggests that dorsal and ventral subregions of the prefrontal cortex process different types of information with dorsal cortex processing spatial/visual information and ventral cortex processing non-spatial/auditory information. While this is apparent in the non-human primate and in some neuroimaging studies, most research in humans indicates that specific task conditions, stimuli or previous experience may bias the recruitment of specific prefrontal regions, suggesting a more flexible role for the frontal lobe during auditory cognition. PMID:25100931

A functional magnetic resonance imaging study mapping the episodic memory encoding network in temporal lobe epilepsy

PubMed Central

Sidhu, Meneka K.; Stretton, Jason; Winston, Gavin P.; Bonelli, Silvia; Centeno, Maria; Vollmar, Christian; Symms, Mark; Thompson, Pamela J.; Koepp, Matthias J.

2013-01-01

Functional magnetic resonance imaging has demonstrated reorganization of memory encoding networks within the temporal lobe in temporal lobe epilepsy, but little is known of the extra-temporal networks in these patients. We investigated the temporal and extra-temporal reorganization of memory encoding networks in refractory temporal lobe epilepsy and the neural correlates of successful subsequent memory formation. We studied 44 patients with unilateral temporal lobe epilepsy and hippocampal sclerosis (24 left) and 26 healthy control subjects. All participants performed a functional magnetic resonance imaging memory encoding paradigm of faces and words with subsequent out-of-scanner recognition assessments. A blocked analysis was used to investigate activations during encoding and neural correlates of subsequent memory were investigated using an event-related analysis. Event-related activations were then correlated with out-of-scanner verbal and visual memory scores. During word encoding, control subjects activated the left prefrontal cortex and left hippocampus whereas patients with left hippocampal sclerosis showed significant additional right temporal and extra-temporal activations. Control subjects displayed subsequent verbal memory effects within left parahippocampal gyrus, left orbitofrontal cortex and fusiform gyrus whereas patients with left hippocampal sclerosis activated only right posterior hippocampus, parahippocampus and fusiform gyrus. Correlational analysis showed that patients with left hippocampal sclerosis with better verbal memory additionally activated left orbitofrontal cortex, anterior cingulate cortex and left posterior hippocampus. During face encoding, control subjects showed right lateralized prefrontal cortex and bilateral hippocampal activations. Patients with right hippocampal sclerosis showed increased temporal activations within the superior temporal gyri bilaterally and no increased extra-temporal areas of activation compared with control subjects. Control subjects showed subsequent visual memory effects within right amygdala, hippocampus, fusiform gyrus and orbitofrontal cortex. Patients with right hippocampal sclerosis showed subsequent visual memory effects within right posterior hippocampus, parahippocampal and fusiform gyri, and predominantly left hemisphere extra-temporal activations within the insula and orbitofrontal cortex. Correlational analysis showed that patients with right hippocampal sclerosis with better visual memory activated the amygdala bilaterally, right anterior parahippocampal gyrus and left insula. Right sided extra-temporal areas of reorganization observed in patients with left hippocampal sclerosis during word encoding and bilateral lateral temporal reorganization in patients with right hippocampal sclerosis during face encoding were not associated with subsequent memory formation. Reorganization within the medial temporal lobe, however, is an efficient process. The orbitofrontal cortex is critical to subsequent memory formation in control subjects and patients. Activations within anterior cingulum and insula correlated with better verbal and visual subsequent memory in patients with left and right hippocampal sclerosis, respectively, representing effective extra-temporal recruitment. PMID:23674488

The inferior, anterior temporal lobes and semantic memory clarified: novel evidence from distortion-corrected fMRI.

PubMed

Visser, M; Embleton, K V; Jefferies, E; Parker, G J; Ralph, M A Lambon

2010-05-01

The neural basis of semantic memory generates considerable debate. Semantic dementia results from bilateral anterior temporal lobe (ATL) atrophy and gives rise to a highly specific impairment of semantic memory, suggesting that this region is a critical neural substrate for semantic processing. Recent rTMS experiments with neurologically-intact participants also indicate that the ATL are a necessary substrate for semantic memory. Exactly which regions within the ATL are important for semantic memory are difficult to detect from these methods (because the damage in SD covers a large part of the ATL). Functional neuroimaging might provide important clues about which specific areas exhibit activation that correlates with normal semantic performance. Neuroimaging studies, however, have not consistently found anterior temporal lobe activation in semantic tasks. A recent meta-analysis indicates that this inconsistency may be due to a collection of technical limitations associated with previous studies, including a reduced field-of-view and magnetic susceptibility artefacts associated with standard gradient echo fMRI. We conducted an fMRI study of semantic memory using a combination of techniques which improve sensitivity to ATL activations whilst preserving whole-brain coverage. As expected from SD patients and ATL rTMS experiments, this method revealed bilateral temporal activation extending from the inferior temporal lobe along the fusiform gyrus to the anterior temporal regions, bilaterally. We suggest that the inferior, anterior temporal lobe region makes a crucial contribution to semantic cognition and utilising this version of fMRI will enable further research on the semantic role of the ATL. 2010 Elsevier Ltd. All rights reserved.

Dissociable Contributions within the Medial Temporal Lobe to Encoding of Object-Location Associations

ERIC Educational Resources Information Center

Sommer, Tobias; Rose, Michael; Glascher, Jan; Wolbers, Thomas; Buchel, Christian

2005-01-01

The crucial role of the medial temporal lobe (MTL) in episodic memory is well established. Although there is little doubt that its anatomical subregions--the hippocampus, peri-, entorhinal and parahippocampal cortex (PHC)--contribute differentially to mnemonic processes, their specific functions in episodic memory are under debate. Data from…

Fluoxetine Restores Spatial Learning but Not Accelerated Forgetting in Mesial Temporal Lobe Epilepsy

ERIC Educational Resources Information Center

Barkas, Lisa; Redhead, Edward; Taylor, Matthew; Shtaya, Anan; Hamilton, Derek A.; Gray, William P.

2012-01-01

Learning and memory dysfunction is the most common neuropsychological effect of mesial temporal lobe epilepsy, and because the underlying neurobiology is poorly understood, there are no pharmacological strategies to help restore memory function in these patients. We have demonstrated impairments in the acquisition of an allocentric spatial task,…

The Consolidation of Object and Context Recognition Memory Involve Different Regions of the Temporal Lobe

ERIC Educational Resources Information Center

Balderas, Israela; Rodriguez-Ortiz, Carlos J.; Salgado-Tonda, Paloma; Chavez-Hurtado, Julio; McGaugh, James L.; Bermudez-Rattoni, Federico

2008-01-01

These experiments investigated the involvement of several temporal lobe regions in consolidation of recognition memory. Anisomycin, a protein synthesis inhibitor, was infused into the hippocampus, perirhinal cortex, insular cortex, or basolateral amygdala of rats immediately after the sample phase of object or object-in-context recognition memory…

Memory Outcomes Following Selective versus Nonselective Temporal Lobe Removal: A Systematic Review

ERIC Educational Resources Information Center

Girgis, Fady

2012-01-01

The surgical removal of brain tissue for the treatment of temporal lobe epilepsy can be either nonselective, as with an anterior temporal lobectomy (ATL), or selective, as with a selective amygdalohippocampectomy (SAH). Although seizure outcomes are similar with both procedures, cognitive and memory outcomes remain a matter of debate. This study…

Enhanced Neuroactivation during Working Memory Task in Postmenopausal Women Receiving Hormone Therapy: A Coordinate-Based Meta-Analysis.

PubMed

Li, Ke; Huang, Xiaoyan; Han, Yingping; Zhang, Jun; Lai, Yuhan; Yuan, Li; Lu, Jiaojiao; Zeng, Dong

2015-01-01

Hormone therapy (HT) has long been thought beneficial for controlling menopausal symptoms and human cognition. Studies have suggested that HT has a positive association with working memory, but no consistent relationship between HT and neural activity has been shown in any cognitive domain. The purpose of this meta-analysis was to assess the convergence of findings from published randomized control trials studies that examined brain activation changes in postmenopausal women. A systematic search for fMRI studies of neural responses during working memory tasks in postmenopausal women was performed. Studies were excluded if they were not treatment studies and did not contain placebo or blank controls. For the purpose of the meta-analysis, 8 studies were identified, with 103 postmenopausal women taking HT and 109 controls. Compared with controls, postmenopausal women who took HT increased activation in the left frontal lobe, including superior frontal gyrus (BA 8), right middle frontal gyrus (BA 9), anterior lobe, paracentral lobule (BA 7), limbic lobe, and anterior cingulate (BA 32). Additionally, decreased activation is noted in the right limbic lobe, including parahippocampal gyrus (BA 28), left parietal lobe, and superior parietal lobule (BA 7). All regions were significant at p ≤ 0.05 with correction for multiple comparisons. Hormone treatment is associated with BOLD signal activation in key anatomical areas during fMRI working memory tasks in healthy hormone-treated postmenopausal women. A positive correlation between activation and task performance suggests that hormone use may benefit working memory.

Decrease of NAA with aging outside the seizure focus in mesial temporal lobe epilepsy--a proton-MRS study at 3 Tesla.

PubMed

Riederer, Franz; Bittsanský, Michal; Lehner-Baumgartner, Eva; Baumgartner, Christoph; Mlynárik, Vladimír; Gruber, Stephan; Moser, Ewald; Kaya, Marihan; Serles, Wolfgang

2007-11-07

There is evidence that chronic pharmacoresistant temporal lobe epilepsy (TLE) is a progressive disorder accompanied by mental deterioration. We investigated effects of aging on cerebral N-acetyl-aspartate (NAA) concentrations in the temporal lobe of 12 patients with pharmacoresistant mesial TLE (mTLE) and 22 healthy controls by means of proton-magnetic resonance spectroscopy ((1)H-MRS) at 3 T. Furthermore, we calculated correlations between NAA concentrations and measures of verbal and figural memory in patients. In mTLE patients but not in healthy controls the concentration of NAA in the lateral temporal lobe was negatively correlated with age. In patients with mTLE NAA in left lateral temporal voxels correlated with verbal memory. NAA in medial temporal voxels did not correlate with age or neuropsychological measures. Significant decrease of NAA with age in the lateral temporal lobe of patients with mTLE provides evidence for progressive neuronal dysfunction with aging. NAA is a marker of neuronal integrity since it correlates with verbal memory.

Severe amnesia following a unilateral temporal lobe stroke.

PubMed

Grewal, Raji P

2003-01-01

A 60 year old right-handed man developed severe amnesia following a left medial temporal stroke as documented by cerebral MRI, MRA and SPECT scans. Neuropsychological evaluation 13 weeks after the stroke showed a profound retrograde amnesia characterised by memory loss for public facts and events over the previous four decades. In addition, autobiographical memory showed selective loss of personal episodic memory with relative preservation of personal semantic memory. The development of this degree of amnesia with these features following a unilateral temporal lobe lesion is unusual. The possible neuroanatomical mechanisms underlying the amnesia and how they relate to current theories of memory loss are discussed.

Accelerated Long-Term Forgetting Is Not Epilepsy Specific: Evidence from Childhood Traumatic Brain Injury.

PubMed

Lah, Suncica; Black, Carly; Gascoigne, Michael B; Gott, Chloe; Epps, Adrienne; Parry, Louise

2017-09-01

Accelerated long-term forgetting (ALF) is characterized by adequate recall after short, but not long delays. ALF is not detected by standardized neuropsychological memory tests. Currently, the prevailing conceptualization of ALF is of a temporal lobe seizure-related phenomenon. Nevertheless, Mayes and colleagues (2003) proposed that ALF may occur when any of the components of the brain network involved in long-term memory formation, or their interaction, is disrupted. This disruption does not have to be caused by temporal lobe seizures for ALF to occur. Here, we investigate this possibility in a group of school-age children who have sustained traumatic brain injury (TBI) (n = 28), as TBI typically disrupts the brain network that is important for long-term memory formation and recall. Healthy control children (n = 62) also participated. Contrary to the dominant conceptualization of ALF being a seizure-related phenomenon, children with TBI showed ALF. Sustaining a severe TBI and diffuse subcortical damage was related to ALF. Individually, 8 of the 13 children with severe TBI presented with ALF. ALF would remain undetected on standardized testing in six of these eight children. One child had the opposite pattern of dissociation, an impaired score on standardized testing, but an average long-term memory score. This is the first study, to our knowledge, to show ALF in patients with TBI, which has remained undiagnosed and untreated in this patient population. Our study also challenges the dominant hypothesis of ALF being a temporal lobe seizure-related phenomenon, and raises a possibility that short-term and long-term memory systems may be independent.

Temporal lobe epilepsy in patients with nonlesional MRI and normal memory: an SEEG study.

PubMed

Suresh, Suraj; Sweet, Jennifer; Fastenau, Philip S; Lüders, Hans; Landazuri, Patrick; Miller, Jonathan

2015-12-01

Temporal lobe epilepsy (TLE) in the absence of MRI abnormalities and memory deficits is often presumed to have an extramesial or even extratemporal source. In this paper the authors report the results of a comprehensive stereoelectroencephalography (SEEG) analysis in patients with TLE with normal MRI images and memory scores. Eighteen patients with medically refractory epilepsy who also had unremarkable MR images and normal verbal and visual memory scores on neuropsychological testing were included in the study. All patients had seizure semiology and video electroencephalography (EEG) findings suggestive of TLE. A standardized SEEG investigation was performed for each patient with electrodes implanted into the mesial and lateral temporal lobe, temporal tip, posterior temporal neocortex, orbitomesiobasal frontal lobe, posterior cingulate gyrus, and insula. This information was used to plan subsequent surgical management. Interictal SEEG abnormalities were observed in the mesial temporal structures in 17 patients (94%) and in the temporal tip in 6 (33%). Seizure onset was exclusively from mesial structures in 13 (72%), exclusively from lateral temporal cortex and/or temporal tip structures in 2 (11%), and independently from mesial and neocortical foci in 3 (17%). No seizure activity was observed arising from any extratemporal location. All patients underwent surgical intervention targeting the temporal lobe and tailored to the SEEG findings, and all experienced significant improvement in seizure frequency with a postoperative follow-up observation period of at least 1 year. This study demonstrates 3 important findings: 1) normal memory does not preclude mesial temporal seizure onset; 2) onset of seizures exclusively from mesial temporal structures without early neocortical involvement is common, even in the absence of memory deficits; and 3) extratemporal seizure onset is rare when video EEG and semiology are consistent with focal TLE.

Slow-oscillatory Transcranial Direct Current Stimulation Modulates Memory in Temporal Lobe Epilepsy by Altering Sleep Spindle Generators: A Possible Rehabilitation Tool.

PubMed

Del Felice, Alessandra; Magalini, Alessandra; Masiero, Stefano

2015-01-01

Temporal lobe epilepsy (TLE) is often associated with memory deficits. Given the putative role for sleep spindles memory consolidation, spindle generators skewed toward the affected lobe in TLE subjects may be a neurophysiological marker of defective memory. Slow-oscillatory transcranial direct current stimulation (sotDCS) during slow waves sleep (SWS) has previously been shown to enhance sleep-dependent memory consolidation by increasing slow-wave sleep and modulating sleep spindles. To test if anodal sotDCS over the affected TL prior to a nap affects sleep spindles and whether this improves memory consolidation. Randomized controlled cross-over study. 12 people with TLE underwent sotDCS (0.75 Hz; 0-250 μV, 30 min) or sham before daytime nap. Declarative verbal and visuospatial learning were tested. Fast and slow spindle signals were recorded by 256-channel EEG during sleep. In both study arms, electrical source imaging (ESI) localized cortical generators. Neuropsychological data were analyzed with general linear model statistics or the Kruskal-Wallis test (P or Z < 0.05), and neurophysiological data tested with the Mann-Whitney t test and binomial distribution test (P or Z < 0.05). An improvement in declarative (P = 0.05) and visuospatial memory performance (P = 0.048) emerged after sotDCS. SotDCS increased slow spindle generators current density (Z = 0.001), with a shift to the anterior cortical areas. Anodal sotDCS over the affected temporal lobe improves declarative and visuospatial memory performance by modulating slow sleep spindles cortical source generators. SotDCS appears a promising tool for memory rehabilitation in people with TLE. Copyright © 2015 Elsevier Inc. All rights reserved.

Verbal Memory Compensation: Application to Left and Right Temporal Lobe Epileptic Patients

ERIC Educational Resources Information Center

Bresson, Christel; Lespinet-Najib, Veronique; Rougier, Alain; Claverie, Bernard; N'Kaoua, Bernard

2007-01-01

This study investigates the compensatory impact of cognitive aids on left and right temporal lobe epileptic patients suffering from verbal memory disorders, who were candidates for surgery. Cognitive aids are defined in the levels-of-processing framework and deal with the depth of encoding, the elaboration of information, and the use of retrieval…

Histopathologic subtype of hippocampal sclerosis and episodic memory performance before and after temporal lobectomy for epilepsy.

PubMed

Saghafi, Shahram; Ferguson, Lisa; Hogue, Olivia; Gales, Jordan M; Prayson, Richard; Busch, Robyn M

2018-04-01

The International League Against Epilepsy (ILAE) proposed a classification system for hippocampal sclerosis (HS) based on location and extent of hippocampal neuron loss. The literature debates the usefulness of this classification system when studying memory in people with temporal lobe epilepsy (TLE) and determining memory outcome after temporal lobe resection (TLR). This study further explores the relationship between HS ILAE subtypes and episodic memory performance in patients with TLE and examines memory outcomes after TLR. This retrospective study identified 213 patients with TLE who underwent TLR and had histopathological evidence of HS (HS ILAE type 1a = 92; type 1b = 103; type 2 = 18). Patients completed the Wechsler Memory Scale-3rd Edition prior to surgery, and 78% of patients had postoperative scores available. Linear regressions examined differences in preoperative memory scores as a function of pathology classification, controlling for potential confounders. Fisher's exact tests were used to compare pathology subtypes on the magnitude of preoperative memory impairment and the proportion of patients who experienced clinically meaningful postoperative memory decline. Individuals with HS ILAE type 2 demonstrated better preoperative verbal memory performance than patients with HS ILAE type 1; however, individual data revealed verbal and visual episodic memory impairments in many patients with HS ILAE type 2. The base rate of postoperative memory decline was similar among all 3 pathology groups. This is the largest reported overall sample and the largest subset of patients with HS ILAE type 2. Group data suggest that patients with HS ILAE type 2 perform better on preoperative memory measures, but individually there were no differences in the magnitude of memory impairment. Following surgery, there were no statistically significant differences between groups in the proportion of patients who declined. Future research should focus on quantitative measurements of hippocampal neuronal loss, and multicenter collaboration is encouraged. Wiley Periodicals, Inc. © 2018 International League Against Epilepsy.

Threat of Punishment Motivates Memory Encoding via Amygdala, Not Midbrain, Interactions with the Medial Temporal Lobe

PubMed Central

Murty, Vishnu P.; LaBar, Kevin S.; Adcock, R. Alison

2012-01-01

Neural circuits associated with motivated declarative encoding and active threat avoidance have both been described, but the relative contribution of these systems to punishment-motivated encoding remains unknown. The current study used functional magnetic resonance imaging in humans to examine mechanisms of declarative memory enhancement when subjects were motivated to avoid punishments that were contingent on forgetting. A motivational cue on each trial informed participants whether they would be punished or not for forgetting an upcoming scene image. Items associated with the threat of shock were better recognized 24 h later. Punishment-motivated enhancements in subsequent memory were associated with anticipatory activation of right amygdala and increases in its functional connectivity with parahippocampal and orbitofrontal cortices. On a trial-by-trial basis, right amygdala activation during the motivational cue predicted hippocampal activation during encoding of the subsequent scene; across participants, the strength of this interaction predicted memory advantages due to motivation. Of note, punishment-motivated learning was not associated with activation of dopaminergic midbrain, as would be predicted by valence-independent models of motivation to learn. These data are consistent with the view that motivation by punishment activates the amygdala, which in turn prepares the medial temporal lobe for memory formation. The findings further suggest a brain system for declarative learning motivated by punishment that is distinct from that for learning motivated by reward. PMID:22745496

Threat of punishment motivates memory encoding via amygdala, not midbrain, interactions with the medial temporal lobe.

PubMed

Murty, Vishnu P; Labar, Kevin S; Adcock, R Alison

2012-06-27

Neural circuits associated with motivated declarative encoding and active threat avoidance have both been described, but the relative contribution of these systems to punishment-motivated encoding remains unknown. The current study used functional magnetic resonance imaging in humans to examine mechanisms of declarative memory enhancement when subjects were motivated to avoid punishments that were contingent on forgetting. A motivational cue on each trial informed participants whether they would be punished or not for forgetting an upcoming scene image. Items associated with the threat of shock were better recognized 24 h later. Punishment-motivated enhancements in subsequent memory were associated with anticipatory activation of right amygdala and increases in its functional connectivity with parahippocampal and orbitofrontal cortices. On a trial-by-trial basis, right amygdala activation during the motivational cue predicted hippocampal activation during encoding of the subsequent scene; across participants, the strength of this interaction predicted memory advantages due to motivation. Of note, punishment-motivated learning was not associated with activation of dopaminergic midbrain, as would be predicted by valence-independent models of motivation to learn. These data are consistent with the view that motivation by punishment activates the amygdala, which in turn prepares the medial temporal lobe for memory formation. The findings further suggest a brain system for declarative learning motivated by punishment that is distinct from that for learning motivated by reward.

Linking DMN connectivity to episodic memory capacity: What can we learn from patients with medial temporal lobe damage?

PubMed Central

McCormick, Cornelia; Protzner, Andrea B.; Barnett, Alexander J.; Cohn, Melanie; Valiante, Taufik A.; McAndrews, Mary Pat

2014-01-01

Computational models predict that focal damage to the Default Mode Network (DMN) causes widespread decreases and increases of functional DMN connectivity. How such alterations impact functioning in a specific cognitive domain such as episodic memory remains relatively unexplored. Here, we show in patients with unilateral medial temporal lobe epilepsy (mTLE) that focal structural damage leads indeed to specific patterns of DMN functional connectivity alterations, specifically decreased connectivity between both medial temporal lobes (MTLs) and the posterior part of the DMN and increased intrahemispheric anterior–posterior connectivity. Importantly, these patterns were associated with better and worse episodic memory capacity, respectively. These distinct patterns, shown here for the first time, suggest that a close dialogue between both MTLs and the posterior components of the DMN is required to fully express the extensive repertoire of episodic memory abilities. PMID:25068108

Sweet Taste and Nutrient Value Subdivide Rewarding Dopaminergic Neurons in Drosophila

PubMed Central

Huetteroth, Wolf; Perisse, Emmanuel; Lin, Suewei; Klappenbach, Martín; Burke, Christopher; Waddell, Scott

2015-01-01

Summary Dopaminergic neurons provide reward learning signals in mammals and insects [1–4]. Recent work in Drosophila has demonstrated that water-reinforcing dopaminergic neurons are different to those for nutritious sugars [5]. Here, we tested whether the sweet taste and nutrient properties of sugar reinforcement further subdivide the fly reward system. We found that dopaminergic neurons expressing the OAMB octopamine receptor [6] specifically convey the short-term reinforcing effects of sweet taste [4]. These dopaminergic neurons project to the β′2 and γ4 regions of the mushroom body lobes. In contrast, nutrient-dependent long-term memory requires different dopaminergic neurons that project to the γ5b regions, and it can be artificially reinforced by those projecting to the β lobe and adjacent α1 region. Surprisingly, whereas artificial implantation and expression of short-term memory occur in satiated flies, formation and expression of artificial long-term memory require flies to be hungry. These studies suggest that short-term and long-term sugar memories have different physiological constraints. They also demonstrate further functional heterogeneity within the rewarding dopaminergic neuron population. PMID:25728694

Semantic Processing Impairment in Patients with Temporal Lobe Epilepsy

PubMed Central

Jaimes-Bautista, Amanda G.; Rodríguez-Camacho, Mario; Martínez-Juárez, Iris E.; Rodríguez-Agudelo, Yaneth

2015-01-01

The impairment in episodic memory system is the best-known cognitive deficit in patients with temporal lobe epilepsy (TLE). Recent studies have shown evidence of semantic disorders, but they have been less studied than episodic memory. The semantic dysfunction in TLE has various cognitive manifestations, such as the presence of language disorders characterized by defects in naming, verbal fluency, or remote semantic information retrieval, which affects the ability of patients to interact with their surroundings. This paper is a review of recent research about the consequences of TLE on semantic processing, considering neuropsychological, electrophysiological, and neuroimaging findings, as well as the functional role of the hippocampus in semantic processing. The evidence from these studies shows disturbance of semantic memory in patients with TLE and supports the theory of declarative memory of the hippocampus. Functional neuroimaging studies show an inefficient compensatory functional reorganization of semantic networks and electrophysiological studies show a lack of N400 effect that could indicate that the deficit in semantic processing in patients with TLE could be due to a failure in the mechanisms of automatic access to lexicon. PMID:26257956

Olfactory learning without the mushroom bodies: Spiking neural network models of the honeybee lateral antennal lobe tract reveal its capacities in odour memory tasks of varied complexities

PubMed Central

2017-01-01

The honeybee olfactory system is a well-established model for understanding functional mechanisms of learning and memory. Olfactory stimuli are first processed in the antennal lobe, and then transferred to the mushroom body and lateral horn through dual pathways termed medial and lateral antennal lobe tracts (m-ALT and l-ALT). Recent studies reported that honeybees can perform elemental learning by associating an odour with a reward signal even after lesions in m-ALT or blocking the mushroom bodies. To test the hypothesis that the lateral pathway (l-ALT) is sufficient for elemental learning, we modelled local computation within glomeruli in antennal lobes with axons of projection neurons connecting to a decision neuron (LHN) in the lateral horn. We show that inhibitory spike-timing dependent plasticity (modelling non-associative plasticity by exposure to different stimuli) in the synapses from local neurons to projection neurons decorrelates the projection neurons’ outputs. The strength of the decorrelations is regulated by global inhibitory feedback within antennal lobes to the projection neurons. By additionally modelling octopaminergic modification of synaptic plasticity among local neurons in the antennal lobes and projection neurons to LHN connections, the model can discriminate and generalize olfactory stimuli. Although positive patterning can be accounted for by the l-ALT model, negative patterning requires further processing and mushroom body circuits. Thus, our model explains several–but not all–types of associative olfactory learning and generalization by a few neural layers of odour processing in the l-ALT. As an outcome of the combination between non-associative and associative learning, the modelling approach allows us to link changes in structural organization of honeybees' antennal lobes with their behavioural performances over the course of their life. PMID:28640825

Olfactory learning without the mushroom bodies: Spiking neural network models of the honeybee lateral antennal lobe tract reveal its capacities in odour memory tasks of varied complexities.

PubMed

MaBouDi, HaDi; Shimazaki, Hideaki; Giurfa, Martin; Chittka, Lars

2017-06-01

The honeybee olfactory system is a well-established model for understanding functional mechanisms of learning and memory. Olfactory stimuli are first processed in the antennal lobe, and then transferred to the mushroom body and lateral horn through dual pathways termed medial and lateral antennal lobe tracts (m-ALT and l-ALT). Recent studies reported that honeybees can perform elemental learning by associating an odour with a reward signal even after lesions in m-ALT or blocking the mushroom bodies. To test the hypothesis that the lateral pathway (l-ALT) is sufficient for elemental learning, we modelled local computation within glomeruli in antennal lobes with axons of projection neurons connecting to a decision neuron (LHN) in the lateral horn. We show that inhibitory spike-timing dependent plasticity (modelling non-associative plasticity by exposure to different stimuli) in the synapses from local neurons to projection neurons decorrelates the projection neurons' outputs. The strength of the decorrelations is regulated by global inhibitory feedback within antennal lobes to the projection neurons. By additionally modelling octopaminergic modification of synaptic plasticity among local neurons in the antennal lobes and projection neurons to LHN connections, the model can discriminate and generalize olfactory stimuli. Although positive patterning can be accounted for by the l-ALT model, negative patterning requires further processing and mushroom body circuits. Thus, our model explains several-but not all-types of associative olfactory learning and generalization by a few neural layers of odour processing in the l-ALT. As an outcome of the combination between non-associative and associative learning, the modelling approach allows us to link changes in structural organization of honeybees' antennal lobes with their behavioural performances over the course of their life.

Contributions of Medial Temporal Lobe and Striatal Memory Systems to Learning and Retrieving Overlapping Spatial Memories

PubMed Central

Brown, Thackery I.; Stern, Chantal E.

2014-01-01

Many life experiences share information with other memories. In order to make decisions based on overlapping memories, we need to distinguish between experiences to determine the appropriate behavior for the current situation. Previous work suggests that the medial temporal lobe (MTL) and medial caudate interact to support the retrieval of overlapping navigational memories in different contexts. The present study used functional magnetic resonance imaging (fMRI) in humans to test the prediction that the MTL and medial caudate play complementary roles in learning novel mazes that cross paths with, and must be distinguished from, previously learned routes. During fMRI scanning, participants navigated virtual routes that were well learned from prior training while also learning new mazes. Critically, some routes learned during scanning shared hallways with those learned during pre-scan training. Overlap between mazes required participants to use contextual cues to select between alternative behaviors. Results demonstrated parahippocampal cortex activity specific for novel spatial cues that distinguish between overlapping routes. The hippocampus and medial caudate were active for learning overlapping spatial memories, and increased their activity for previously learned routes when they became context dependent. Our findings provide novel evidence that the MTL and medial caudate play complementary roles in the learning, updating, and execution of context-dependent navigational behaviors. PMID:23448868

Normalization for sparse encoding of odors by a wide-field interneuron.

PubMed

Papadopoulou, Maria; Cassenaer, Stijn; Nowotny, Thomas; Laurent, Gilles

2011-05-06

Sparse coding presents practical advantages for sensory representations and memory storage. In the insect olfactory system, the representation of general odors is dense in the antennal lobes but sparse in the mushroom bodies, only one synapse downstream. In locusts, this transformation relies on the oscillatory structure of antennal lobe output, feed-forward inhibitory circuits, intrinsic properties of mushroom body neurons, and connectivity between antennal lobe and mushroom bodies. Here we show the existence of a normalizing negative-feedback loop within the mushroom body to maintain sparse output over a wide range of input conditions. This loop consists of an identifiable "giant" nonspiking inhibitory interneuron with ubiquitous connectivity and graded release properties.

Neuropsychological functioning and brain energetics of drug resistant mesial temporal lobe epilepsy patients.

PubMed

Osório, Camila Moreira; Latini, Alexandra; Leal, Rodrigo Bainy; de Oliveira Thais, Maria Emília Rodrigues; Vascouto, Helena Dresch; Remor, Aline Pertile; Lopes, Mark William; Linhares, Marcelo Neves; Ben, Juliana; de Paula Martins, Roberta; Prediger, Rui Daniel; Hoeller, Alexandre Ademar; Markowitsch, Hans Joachim; Wolf, Peter; Lin, Kátia; Walz, Roger

2017-12-01

Interictal hypometabolism is commonly measured by 18-fluoro-deoxyglucose Positron Emission Tomography (FDG-PET) in the temporal lobe of patients with mesial temporal lobe epilepsy (MTLE-HS). Left temporal lobe interictal FDG-PET hypometabolism has been associated with verbal memory impairment, while right temporal lobe FDG-PET hypometabolism is associated with nonverbal memory impairment. The biochemical mechanisms involved in these findings remain unknown. In comparison to healthy controls (n=21), surgically treated patients with MTLE-HS (n=32, left side=17) had significant lower scores in the Rey Auditory Verbal Learning Test (RAVLT retention and delayed), Logical Memory II (LMII), Boston Naming test (BNT), Letter Fluency and Category Fluency. We investigated whether enzymatic activities of the mitochondrial enzymes Complex I (C I), Complex II (C II), Complex IV (C IV) and Succinate Dehydrogenase (SDH) from the resected samples of the middle temporal neocortex (mTCx), amygdala (AMY) and hippocampus (HIP) were associated with performance in the RAVLT, LMII, BNT and fluency tests of our patients. After controlling for the side of hippocampus sclerosis, years of education, disease duration, antiepileptic treatment and seizure outcome after surgery, no independent associations were observed between the cognitive test scores and the analyzed mitochondrial enzymatic activities (p>0.37). Results indicate that memory and language impairment observed in MTLE-HS patients are not strongly associated with the levels of mitochondrial CI, CII, SDH and C IV enzymatic activities in the temporal lobe structures ipsilateral to the HS lesion. Copyright © 2017 Elsevier B.V. All rights reserved.

Abnormal Neural Network of Primary Insomnia: Evidence from Spatial Working Memory Task fMRI.

PubMed

Li, Yongli; Liu, Liya; Wang, Enfeng; Zhang, Hongju; Dou, Shewei; Tong, Li; Cheng, Jingliang; Chen, Chuanliang; Shi, Dapeng

2016-01-01

Contemporary functional MRI (fMRI) methods can provide a wealth of information about the neural mechanisms associated with primary insomnia (PI), which centrally involve neural network circuits related to spatial working memory. A total of 30 participants diagnosed with PI and without atypical brain anatomy were selected along with 30 age- and gender-matched healthy controls. Subjects were administered the Pittsburgh Sleep Quality Index (PSQI), Hamilton Rating Scale for Depression and clinical assessments of spatial working memory, followed by an MRI scan and fMRI in spatial memory task state. Statistically significant differences between PSQI and spatial working memory were observed between PI patients and controls (p < 0.01). Activation of neural networks related to spatial memory task state in the PI group was observed at the left temporal lobe, left occipital lobe and right frontal lobe. Lower levels of activation were observed in the left parahippocampal gyrus, right parahippocampal gyrus, bilateral temporal cortex, frontal cortex and superior parietal lobule. Participants with PI exhibited characteristic abnormalities in the neural network connectivity related to spatial working memory. These results may be indicative of an underlying pathological mechanism related to spatial working memory deterioration in PI, analogous to recently described mechanisms in other mental health disorders. © 2016 S. Karger AG, Basel.

Temporal Lobe and Frontal-Subcortical Dissociations in Non-Demented Parkinson's Disease with Verbal Memory Impairment.

PubMed

Tanner, Jared J; Mareci, Thomas H; Okun, Michael S; Bowers, Dawn; Libon, David J; Price, Catherine C

2015-01-01

The current investigation examined verbal memory in idiopathic non-dementia Parkinson's disease and the significance of the left entorhinal cortex and left entorhinal-retrosplenial region connections (via temporal cingulum) on memory impairment in Parkinson's disease. Forty non-demented Parkinson's disease patients and forty non-Parkinson's disease controls completed two verbal memory tests--a wordlist measure (Philadelphia repeatable Verbal Memory Test) and a story measure (Logical Memory). All participants received T1-weighted and diffusion magnetic resonance imaging (3T; Siemens) sequences. Left entorhinal volume and left entorhinal-retrosplenial connectivity (temporal cingulum edge weight) were the primary imaging variables of interest with frontal lobe thickness and subcortical structure volumes as dissociating variables. Individuals with Parkinson's disease showed worse verbal memory, smaller entorhinal volumes, but did not differ in entorhinal-retrosplenial connectivity. For Parkinson's disease entorhinal-retrosplenial edge weight had the strongest associations with verbal memory. A subset of Parkinson's disease patients (23%) had deficits (z-scores < -1.5) across both memory measures. Relative to non-impaired Parkinson's peers, this memory-impaired group had smaller entorhinal volumes. Although entorhinal cortex volume was significantly reduced in Parkinson's disease patients relative to non-Parkinson's peers, only white matter connections associated with the entorhinal cortex were significantly associated with verbal memory performance in our sample. There was also no suggestion of contribution from frontal-subcortical gray or frontal white matter regions. These findings argue for additional investigation into medial temporal lobe gray and white matter connectivity for understanding memory in Parkinson's disease.

Temporal Lobe Epilepsy and the Selective Reminding Test: The Conventional 30-Minute Delay Suffices

ERIC Educational Resources Information Center

Bell, Brian D.; Fine, Jason; Dow, Christian; Seidenberg, Michael; Hermann, Bruce P.

2005-01-01

Conventional memory assessment may fail to identify memory dysfunction characterized by intact recall for a relatively brief period but rapid forgetting thereafter. This study assessed learning and retention after 30-min and 24-hr delays on auditory and visual selective reminding tests (SRTs) in right (n=20) and left (n=22) temporal lobe epilepsy…

The Impact of Sex and Language Dominance on Material-Specific Memory Before and After Left Temporal Lobe Surgery

ERIC Educational Resources Information Center

Helmstaedter, C.; Brosch, T.; Kurthen, M.; Elger, C. E.

2004-01-01

Recent findings raised evidence that in early-onset left temporal lobe epilepsy, women show greater functional plasticity for verbal memory than men. In particular, women with lesion- or epilepsy-driven atypical language dominance show an advantage over men. The question asked in this study was whether there is evidence of sex- and language…

Distinct medial temporal networks encode surprise during motivation by reward versus punishment

PubMed Central

Murty, Vishnu P.; LaBar, Kevin S.; Adcock, R. Alison

2016-01-01

Adaptive motivated behavior requires predictive internal representations of the environment, and surprising events are indications for encoding new representations of the environment. The medial temporal lobe memory system, including the hippocampus and surrounding cortex, encodes surprising events and is influenced by motivational state. Because behavior reflects the goals of an individual, we investigated whether motivational valence (i.e., pursuing rewards versus avoiding punishments) also impacts neural and mnemonic encoding of surprising events. During functional magnetic resonance imaging (fMRI), participants encountered perceptually unexpected events either during the pursuit of rewards or avoidance of punishments. Despite similar levels of motivation across groups, reward and punishment facilitated the processing of surprising events in different medial temporal lobe regions. Whereas during reward motivation, perceptual surprises enhanced activation in the hippocampus, during punishment motivation surprises instead enhanced activation in parahippocampal cortex. Further, we found that reward motivation facilitated hippocampal coupling with ventromedial PFC, whereas punishment motivation facilitated parahippocampal cortical coupling with orbitofrontal cortex. Behaviorally, post-scan testing revealed that reward, but not punishment, motivation resulted in greater memory selectivity for surprising events encountered during goal pursuit. Together these findings demonstrate that neuromodulatory systems engaged by anticipation of reward and punishment target separate components of the medial temporal lobe, modulating medial temporal lobe sensitivity and connectivity. Thus, reward and punishment motivation yield distinct neural contexts for learning, with distinct consequences for how surprises are incorporated into predictive mnemonic models of the environment. PMID:26854903

Distinct medial temporal networks encode surprise during motivation by reward versus punishment.

PubMed

Murty, Vishnu P; LaBar, Kevin S; Adcock, R Alison

2016-10-01

Adaptive motivated behavior requires predictive internal representations of the environment, and surprising events are indications for encoding new representations of the environment. The medial temporal lobe memory system, including the hippocampus and surrounding cortex, encodes surprising events and is influenced by motivational state. Because behavior reflects the goals of an individual, we investigated whether motivational valence (i.e., pursuing rewards versus avoiding punishments) also impacts neural and mnemonic encoding of surprising events. During functional magnetic resonance imaging (fMRI), participants encountered perceptually unexpected events either during the pursuit of rewards or avoidance of punishments. Despite similar levels of motivation across groups, reward and punishment facilitated the processing of surprising events in different medial temporal lobe regions. Whereas during reward motivation, perceptual surprises enhanced activation in the hippocampus, during punishment motivation surprises instead enhanced activation in parahippocampal cortex. Further, we found that reward motivation facilitated hippocampal coupling with ventromedial PFC, whereas punishment motivation facilitated parahippocampal cortical coupling with orbitofrontal cortex. Behaviorally, post-scan testing revealed that reward, but not punishment, motivation resulted in greater memory selectivity for surprising events encountered during goal pursuit. Together these findings demonstrate that neuromodulatory systems engaged by anticipation of reward and punishment target separate components of the medial temporal lobe, modulating medial temporal lobe sensitivity and connectivity. Thus, reward and punishment motivation yield distinct neural contexts for learning, with distinct consequences for how surprises are incorporated into predictive mnemonic models of the environment. Copyright © 2016 Elsevier Inc. All rights reserved.

The gyri of the octopus vertical lobe have distinct neurochemical identities.

PubMed

Shigeno, Shuichi; Ragsdale, Clifton W

2015-06-15

The cephalopod vertical lobe is the largest learning and memory structure known in invertebrate nervous systems. It is part of the visual learning circuit of the central brain, which also includes the superior frontal and subvertical lobes. Despite the well-established functional importance of this system, little is known about neuropil organization of these structures and there is to date no evidence that the five longitudinal gyri of the vertical lobe, perhaps the most distinctive morphological feature of the octopus brain, differ in their connections or molecular identities. We studied the histochemical organization of these structures in hatchling and adult Octopus bimaculoides brains with immunostaining for serotonin, octopus gonadotropin-releasing hormone (oGNRH), and octopressin-neurophysin (OP-NP). Our major finding is that the five lobules forming the vertical lobe gyri have distinct neurochemical signatures. This is most prominent in the hatchling brain, where the median and mediolateral lobules are enriched in OP-NP fibers, the lateral lobule is marked by oGNRH innervation, and serotonin immunostaining heavily labels the median and lateral lobules. A major source of input to the vertical lobe is the superior frontal lobe, which is dominated by a neuropil of interweaving fiber bundles. We have found that this neuropil also has an intrinsic neurochemical organization: it is partitioned into territories alternately enriched or impoverished in oGNRH-containing fascicles. Our findings establish that the constituent lobes of the octopus superior frontal-vertical system have an intricate internal anatomy, one likely to reflect the presence of functional subsystems within cephalopod learning circuitry. © 2015 Wiley Periodicals, Inc.

Sensory memory for odors is encoded in spontaneous correlated activity between olfactory glomeruli.

PubMed

Galán, Roberto F; Weidert, Marcel; Menzel, Randolf; Herz, Andreas V M; Galizia, C Giovanni

2006-01-01

Sensory memory is a short-lived persistence of a sensory stimulus in the nervous system, such as iconic memory in the visual system. However, little is known about the mechanisms underlying olfactory sensory memory. We have therefore analyzed the effect of odor stimuli on the first odor-processing network in the honeybee brain, the antennal lobe, which corresponds to the vertebrate olfactory bulb. We stained output neurons with a calcium-sensitive dye and measured across-glomerular patterns of spontaneous activity before and after a stimulus. Such a single-odor presentation changed the relative timing of spontaneous activity across glomeruli in accordance with Hebb's theory of learning. Moreover, during the first few minutes after odor presentation, correlations between the spontaneous activity fluctuations suffice to reconstruct the stimulus. As spontaneous activity is ubiquitous in the brain, modifiable fluctuations could provide an ideal substrate for Hebbian reverberations and sensory memory in other neural systems.

The neural circuitry of visual artistic production and appreciation: A proposition.

PubMed

Chakravarty, Ambar

2012-04-01

The nondominant inferior parietal lobule is probably a major "store house" of artistic creativity. The ventromedial prefrontal lobe (VMPFL) is supposed to be involved in creative cognition and the dorsolateral prefrontal lobe (DLPFL) in creative output. The conceptual ventral and dorsal visual system pathways likely represent the inferior and superior longitudinal fasciculi. During artistic production, conceptualization is conceived in the VMPFL and the executive part is operated through the DLFPL. The latter transfers the concept to the visual brain through the superior longitudinal fasciculus (SLF), relaying on its path to the parietal cortex. The conceptualization at VMPFL is influenced by activity from the anterior temporal lobe through the uncinate fasciculus and limbic system pathways. The final visual image formed in the visual brain is subsequently transferred back to the DLPFL through the SLF and then handed over to the motor cortex for execution. During art appreciation, the image at the visual brain is transferred to the frontal lobe through the SLF and there it is matched with emotional and memory inputs from the anterior temporal lobe transmitted through the uncinate fasiculus. Beauty is perceived at the VMPFL and transferred through the uncinate fasciculus to the hippocampo-amygdaloid complex in the anterior temporal lobe. The limbic system (Papez circuit) is activated and emotion of appreciation is evoked. It is postulated that in practice the entire circuitry is activated simultaneously.

The neural circuitry of visual artistic production and appreciation: A proposition

PubMed Central

Chakravarty, Ambar

2012-01-01

The nondominant inferior parietal lobule is probably a major “store house” of artistic creativity. The ventromedial prefrontal lobe (VMPFL) is supposed to be involved in creative cognition and the dorsolateral prefrontal lobe (DLPFL) in creative output. The conceptual ventral and dorsal visual system pathways likely represent the inferior and superior longitudinal fasciculi. During artistic production, conceptualization is conceived in the VMPFL and the executive part is operated through the DLFPL. The latter transfers the concept to the visual brain through the superior longitudinal fasciculus (SLF), relaying on its path to the parietal cortex. The conceptualization at VMPFL is influenced by activity from the anterior temporal lobe through the uncinate fasciculus and limbic system pathways. The final visual image formed in the visual brain is subsequently transferred back to the DLPFL through the SLF and then handed over to the motor cortex for execution. During art appreciation, the image at the visual brain is transferred to the frontal lobe through the SLF and there it is matched with emotional and memory inputs from the anterior temporal lobe transmitted through the uncinate fasiculus. Beauty is perceived at the VMPFL and transferred through the uncinate fasciculus to the hippocampo–amygdaloid complex in the anterior temporal lobe. The limbic system (Papez circuit) is activated and emotion of appreciation is evoked. It is postulated that in practice the entire circuitry is activated simultaneously. PMID:22566716

Encoding and immediate retrieval tasks in patients with epilepsy: A functional MRI study of verbal and visual memory.

PubMed

Saddiki, Najat; Hennion, Sophie; Viard, Romain; Ramdane, Nassima; Lopes, Renaud; Baroncini, Marc; Szurhaj, William; Reyns, Nicolas; Pruvo, Jean Pierre; Delmaire, Christine

2018-05-01

Medial lobe temporal structures and more specifically the hippocampus play a decisive role in episodic memory. Most of the memory functional magnetic resonance imaging (fMRI) studies evaluate the encoding phase; the retrieval phase being performed outside the MRI. We aimed to determine the ability to reveal greater hippocampal fMRI activations during retrieval phase. Thirty-five epileptic patients underwent a two-step memory fMRI. During encoding phase, subjects were requested to identify the feminine or masculine gender of faces and words presented, in order to encourage stimulus encoding. One hour after, during retrieval phase, subjects had to recognize the word and face. We used an event-related design to identify hippocampal activations. There was no significant difference between patients with left temporal lobe epilepsy, patients with right temporal lobe epilepsy and patients with extratemporal lobe epilepsy on verbal and visual learning task. For words, patients demonstrated significantly more bilateral hippocampal activation for retrieval task than encoding task and when the tasks were associated than during encoding alone. Significant difference was seen between face-encoding alone and face retrieval alone. This study demonstrates the essential contribution of the retrieval task during a fMRI memory task but the number of patients with hippocampal activations was greater when the two tasks were taken into account. Copyright © 2018. Published by Elsevier Masson SAS.

[Predictors of verbal memory decline following temporal lobe surgery].

PubMed

de Vanssay-Maigne, A; Boutin, M; Baudoin-Chial, S

2008-05-01

Verbal memory decline can occur after temporal lobe surgery, especially when the left dominant hemisphere is involved. This potential functional risk must be evaluated before surgery. Among all factors that have been identified by several studies, the side of surgery (left dominant) and high baseline memory performance have been found to be predictive of verbal memory decline. Other factors such as etiology, sex, age at surgery, age at seizure onset, and duration may influence memory decline, but the results are not clear. Our purpose was to identify, in our population of patients and among all risk factors, those that may be predictive of verbal memory decline. Logistic regression was used to examine the effect of each factor on the postoperative verbal memory index (WMS-R) in 101 patients who underwent a right (n=49) or left (n=52) anterior temporal lobe resection. In the group as a whole, 22 % of the patients demonstrated verbal memory decline of more than one standard deviation. The verbal memory decline was significantly related to surgery on the left side and a high level of verbal memory performance. These factors were significant predictors of decline. The other factors (etiology, sex, age at surgery, age at seizure onset, and duration) were not found to be predictive of this decline. Our analysis demonstrates that the patients who are most at risk of undergoing verbal memory deterioration are those who undergo left-sided temporal resection and have good memory scores preoperatively. The contradictions found in the literature about the other factors could be explained by the diversity of the tests and criteria used to assess memory decline.

The Medial Temporal Lobe and the Left Inferior Prefrontal Cortex Jointly Support Interference Resolution in Verbal Working Memory

ERIC Educational Resources Information Center

Oztekin, Ilke; Curtis, Clayton E.; McElree, Brian

2009-01-01

During working memory retrieval, proactive interference (PI) can be induced by semantic similarity and episodic familiarity. Here, we used fMRI to test hypotheses about the role of the left inferior frontal gyrus (LIFG) and the medial temporal lobe (MTL) regions in successful resolution of PI. Participants studied six-word lists and responded to a…

On the Processing of Semantic Aspects of Experience in the Anterior Medial Temporal Lobe: An Event-Related fMRI Study

ERIC Educational Resources Information Center

Meyer, Patric; Mecklinger, Axel; Friederici, Angela D.

2010-01-01

Recognition memory based on familiarity judgments is a form of declarative memory that has been repeatedly associated with the anterior medial temporal lobe. It has been argued that this region sustains familiarity-based recognition not only by retrieving item-specific information but also by coding for those semantic aspects of an event that…

The development of neural correlates for memory formation

PubMed Central

Ofen, Noa

2012-01-01

A growing body of literature considers the development of episodic memory systems in the brain; the majority are neuroimaging studies conducted during memory encoding in order to explore developmental trajectories in memory formation. This review considers evidence from behavioral studies of memory development, neural correlates of memory formation in adults, and structural brain development, all of which form the foundation of a developmental cognitive neuroscience approach to memory development. I then aim to integrate the current evidence from developmental functional neuroimaging studies of memory formation with respect to three hypotheses. First, memory development reflects the development in the use of memory strategies, linked to prefrontal cortex. Second, developmental effects within the medial temporal lobes are more complex, and correspond to current notions about the nature in which the MTL support the formation of memory. Third, neurocognitive changes in content representation influence memory. Open issues and current directions are discussed. PMID:22414608

Association of Hippocampal Substructure Resting-State Functional Connectivity with Memory Performance in Older Adults.

PubMed

Smagula, Stephen F; Karim, Helmet T; Rangarajan, Anusha; Santos, Fernando Pasquini; Wood, Sossena C; Santini, Tales; Jakicic, John M; Reynolds, Charles F; Cameron, Judy L; Vallejo, Abbe N; Butters, Meryl A; Rosano, Caterina; Ibrahim, Tamer S; Erickson, Kirk I; Aizenstein, Howard J

2018-06-01

Hippocampal hyperactivation marks preclinical dementia pathophysiology, potentially due to differences in the connectivity of specific medial temporal lobe structures. Our aims were to characterize the resting-state functional connectivity of medial temporal lobe sub-structures in older adults, and evaluate whether specific substructural (rather than global) functional connectivity relates to memory function. In 15 adults (mean age: 69 years), we evaluated the resting state functional connectivity of medial temporal lobe substructures: dentate/Cornu Ammonis (CA) 4, CA1, CA2/3, subiculum, the molecular layer, entorhinal cortex, and parahippocampus. We used 7-Tesla susceptibility weighted imaging and magnetization-prepared rapid gradient echo sequences to segment substructures of the hippocampus, which were used as structural seeds for examining functional connectivity in a resting BOLD sequence. We then assessed correlations between functional connectivity with memory performance (short and long delay free recall on the California Verbal Learning Test [CVLT]). All the seed regions had significant connectivity within the temporal lobe (including the fusiform, temporal, and lingual gyri). The left CA1 was the only seed with significant functional connectivity to the amygdala. The left entorhinal cortex was the only seed to have significant functional connectivity with frontal cortex (anterior cingulate and superior frontal gyrus). Only higher left dentate-left lingual connectivity was associated with poorer CVLT performance (Spearman r = -0.81, p = 0.0003, Benjamini-Hochberg false discovery rate: 0.01) after multiple comparison correction. Rather than global hyper-connectivity of the medial temporal lobe, left dentate-lingual connectivity may provide a specific assay of medial temporal lobe hyper-connectivity relevant to memory in aging. Copyright © 2018 American Association for Geriatric Psychiatry. Published by Elsevier Inc. All rights reserved.

Memory-Guided Attention: Independent Contributions of the Hippocampus and Striatum.

PubMed

Goldfarb, Elizabeth V; Chun, Marvin M; Phelps, Elizabeth A

2016-01-20

Memory can strongly influence how attention is deployed in future encounters. Though memory dependent on the medial temporal lobes has been shown to drive attention, how other memory systems could concurrently and comparably enhance attention is less clear. Here, we demonstrate that both reinforcement learning and context memory facilitate attention in a visual search task. Using functional magnetic resonance imaging, we dissociate the mechanisms by which these memories guide attention: trial by trial, the hippocampus (not the striatum) predicted attention benefits from context memory, while the striatum (not the hippocampus) predicted facilitation from rewarded stimulus-response associations. Responses in these regions were also distinctly correlated with individual differences in each type of memory-guided attention. This study provides novel evidence for the role of the striatum in guiding attention, dissociable from hippocampus-dependent context memory.

Memory-Guided Attention: Independent Contributions of the Hippocampus and Striatum

PubMed Central

Goldfarb, Elizabeth V.; Chun, Marvin M.; Phelps, Elizabeth A.

2015-01-01

SUMMARY Memory can strongly influence how attention is deployed in future encounters. Though memory dependent on the medial temporal lobes has been shown to drive attention, how other memory systems could concurrently and comparably enhance attention is less clear. Here, we demonstrate that both reinforcement learning and context memory facilitate attention in a visual search task. Using functional magnetic resonance imaging, we dissociate the mechanisms by which these memories guide attention: trial by trial, the hippocampus (not the striatum) predicted attention benefits from context memory, while the striatum (not the hippocampus) predicted facilitation from rewarded stimulus-response associations. Responses in these regions were also distinctly correlated with individual differences in each type of memory-guided attention. This study provides novel evidence for the role of the striatum in guiding attention, dissociable from hippocampus-dependent context memory. PMID:26777274

Verbal Dominant Memory Impairment and Low Risk for Post-operative Memory Worsening in Both Left and Right Temporal Lobe Epilepsy Associated with Hippocampal Sclerosis.

PubMed

Khalil, Amr Farid; Iwasaki, Masaki; Nishio, Yoshiyuki; Jin, Kazutaka; Nakasato, Nobukazu; Tominaga, Teiji

2016-11-15

Post-operative memory changes after temporal lobe surgery have been established mainly by group analysis of cognitive outcome. This study investigated individual patient-based memory outcome in surgically-treated patients with mesial temporal lobe epilepsy (TLE). This study included 84 consecutive patients with intractable TLE caused by unilateral hippocampal sclerosis (HS) who underwent epilepsy surgery (47 females, 41 left [Lt] TLE). Memory functions were evaluated with the Wechsler Memory Scale-Revised before and at 1 year after surgery. Pre-operative memory function was classified into three patterns: verbal dominant memory impairment (Verb-D), visual dominant impairment (Vis-D), and no material-specific impairment. Post-operative changes in verbal and visual memory indices were classified into meaningful improvement, worsening, or no significant changes. Pre-operative patterns and post-operative changes in verbal and visual memory function were compared between the Lt and right (Rt) TLE groups. Pre-operatively, Verb-D was the most common type of impairment in both the Lt and Rt TLE groups (65.9 and 48.8%), and verbal memory indices were lower than visual memory indices, especially in the Lt compared with Rt TLE group. Vis-D was observed only in 11.6% of Rt and 7.3% of Lt TLE patients. Post-operatively, meaningful improvement of memory indices was observed in 23.3-36.6% of the patients, and the memory improvement was equivalent between Lt and Rt TLE groups and between verbal and visual materials. In conclusion, Verb-D is most commonly observed in patients with both the Lt and Rt TLE associated with HS. Hippocampectomy can improve memory indices in such patients regardless of the side of surgery and the function impaired.

[Application of spatial working memory task fMRI in evaluation of primary insomnia patient's cognitive dysfunction].

PubMed

Dou, Shewei; Wang, Enfeng; Zhang, Hongju; Tong, Li; Zhang, Xiaoqi; Shi, Dapeng; Cheng, Jingliang; Li, Yongli

2015-06-02

To explore abnormal brain activation of spatial working memory in primary insomnia and its potential neuromechanism. we recruited 30 cases primary insomnia (PI) patients and 30 cases age, gender matched healthy control (HC) subjects from July 2013 to December 2013, the diagnosis of primary insomnia matched the diagnosis criterion of DSM-IV and Classification and diagnostic criteria of mental disorders in China third edition (CCMD-3). All the subjects attended the tests of PSQI, HAMA, HAMD and index of spatial working memory. And then, we collected the data of routine MRI and spatial working memory task fMRI on 3.0 T MRI scanner. After that, we used SPM8 and REST1.8 to analyze the fMRI data, compared difference of PSQI, HAMA, HAMD, index of spatial working memory and brain activation of spatial working memory between PI group and HC group. There were significant difference between PI group and HC group in PSQI, HAMA, HAMD and index of spatial working memory (P < 0.05). In the spatial working memory related activate brain region, compared with HC group, left temporal lobe, occipital lobe and right frontal lobe activation increased and bilateral parahippocampalis, temporal cortex, frontal cortex and superior parietal lobule activation reduced in PI group. Spatial working memory task fMRI revealed the pathological mechanisms of cognitive dysfunction of clinical spatial working memory and emotional disorder in primary insomnia patients.

Prospective memory and frontal lobe function.

PubMed

Neulinger, Kerryn; Oram, Joanne; Tinson, Helen; O'Gorman, John; Shum, David H K

2016-01-01

The study sought to examine the role of frontal lobe functioning in focal prospective memory (PM) performance and its relation to PM deficit in older adults. PM and working memory (WM) differences were studied in younger aged (n = 21), older aged (n = 20), and frontal injury (n = 14) groups. An event-based focal PM task was employed and three measures of WM were administered. The younger aged group differed from the other two groups in showing significantly higher scores on PM and on one of the WM measures, but there were no differences at a statistically significant level between the older aged group and the frontal injury groups on any of the memory measures. There were, however, some differences in correlations with a WM measure between groups. It is concluded that there are similarities and differences in the deficits in PM between older adults and patients with frontal lobe injury on focal as well as nonfocal PM tasks.

Stimulation of the human medial temporal lobe between learning and recall selectively enhances forgetting

PubMed Central

Merkow, Maxwell B.; Burke, John F.; Ramayya, Ashwin G.; Sharan, Ashwini D.; Sperling, Michael R.; Kahana, Michael J.

2017-01-01

Background Direct electrical stimulation applied to the human medial temporal lobe (MTL) typically disrupts performance on memory tasks, however, the mechanism underlying this effect is not known. Objective To study the effects of MTL stimulation on memory performance Methods We studied the effects of MTL stimulation on memory in five patients undergoing invasive electrocorticographic monitoring during various phases of a memory task (encoding, distractor, recall). Results We found that MTL stimulation disrupted memory performance in a timing-dependent manner; we observed greater forgetting when applying stimulation during the delay between encoding and recall, compared to when it was applied during encoding or recall. Conclusions The results suggest that recall is most dependent on the MTL between learning and retrieval. PMID:28073638

Dissociating Medial Temporal and Striatal Memory Systems With a Same/Different Matching Task: Evidence for Two Neural Systems in Human Recognition.

PubMed

Sinha, Neha; Glass, Arnold Lewis

2017-01-01

The medial temporal lobe and striatum have both been implicated as brain substrates of memory and learning. Here, we show dissociation between these two memory systems using a same/different matching task, in which subjects judged whether four-letter strings were the same or different. Different RT was determined by the left-to-right location of the first letter different between the study and test string, consistent with a left-to-right comparison of the study and test strings, terminating when a difference was found. This comparison process results in same responses being slower than different responses. Nevertheless, same responses were faster than different responses. Same responses were associated with hippocampus activation. Different responses were associated with both caudate and hippocampus activation. These findings are consistent with the dual-system hypothesis of mammalian memory and extend the model to human visual recognition.

Impairment of exploratory behavior and spatial memory in adolescent rats in lithium-pilocarpine model of temporal lobe epilepsy.

PubMed

Kalemenev, S V; Zubareva, O E; Frolova, E V; Sizov, V V; Lavrentyeva, V V; Lukomskaya, N Ya; Kim, K Kh; Zaitsev, A V; Magazanik, L G

2015-01-01

Cognitive impairment in six-week -old rats has been studied in the lithium-pilocarpine model of adolescent temporal lobe epilepsy in humans. The pilocarpine-treated rats (n =21) exhibited (a) a decreased exploratory activity in comparison with control rats (n = 20) in the open field (OP) test and (b) a slower extinction of exploratory behavior in repeated OP tests. The Morris Water Maze (MWM) test showed that the effect of training was less pronounced in the pilocarpine-treated rats, which demonstrated disruption of predominantly short-term memory. Therefore, our study has shown that lithium-pilocarpine seizures induce substantial changes in exploratory behavior and spatial memory in adolescent rats. OP and MWM tests can be used in the search of drugs reducing cognitive impairments associated with temporal lobe epilepsy.

True and False Memories, Parietal Cortex, and Confidence Judgments

ERIC Educational Resources Information Center

Urgolites, Zhisen J.; Smith, Christine N.; Squire, Larry R.

2015-01-01

Recent studies have asked whether activity in the medial temporal lobe (MTL) and the neocortex can distinguish true memory from false memory. A frequent complication has been that the confidence associated with correct memory judgments (true memory) is typically higher than the confidence associated with incorrect memory judgments (false memory).…

Regionally compartmentalized resident memory T cells mediate naturally acquired protection against pneumococcal pneumonia.

PubMed

Smith, N Ms; Wasserman, G A; Coleman, F T; Hilliard, K L; Yamamoto, K; Lipsitz, E; Malley, R; Dooms, H; Jones, M R; Quinton, L J; Mizgerd, J P

2018-01-01

As children age, they become less susceptible to the diverse microbes causing pneumonia. These microbes are pathobionts that infect the respiratory tract multiple times during childhood, generating immunological memory. To elucidate mechanisms of such naturally acquired immune protection against pneumonia, we modeled a relevant immunological history in mice by infecting their airways with mismatched serotypes of Streptococcus pneumoniae (pneumococcus). Previous pneumococcal infections provided protection against a heterotypic, highly virulent pneumococcus, as evidenced by reduced bacterial burdens and long-term sterilizing immunity. This protection was diminished by depletion of CD4 + cells prior to the final infection. The resolution of previous pneumococcal infections seeded the lungs with CD4 + resident memory T (T RM ) cells, which responded to heterotypic pneumococcus stimulation by producing multiple effector cytokines, particularly interleukin (IL)-17A. Following lobar pneumonias, IL-17-producing CD4 + T RM cells were confined to the previously infected lobe, rather than dispersed throughout the lower respiratory tract. Importantly, pneumonia protection also was confined to that immunologically experienced lobe. Thus regionally localized memory cells provide superior local tissue protection to that mediated by systemic or central memory immune defenses. We conclude that respiratory bacterial infections elicit CD4 + T RM cells that fill a local niche to optimize heterotypic protection of the affected tissue, preventing pneumonia.

Subjective memory complaints are associated with brain activation supporting successful memory encoding.

PubMed

Hayes, Jessica M; Tang, Lingfei; Viviano, Raymond P; van Rooden, Sanneke; Ofen, Noa; Damoiseaux, Jessica S

2017-12-01

Subjective memory complaints, the perceived decline in cognitive abilities in the absence of clinical deficits, may precede Alzheimer's disease. Individuals with subjective memory complaints show differential brain activation during memory encoding; however, whether such differences contribute to successful memory formation remains unclear. Here, we investigated how subsequent memory effects, activation which is greater for hits than misses during an encoding task, differed between healthy older adults aged 50 to 85 years with (n = 23) and without (n = 41) memory complaints. Older adults with memory complaints, compared to those without, showed lower subsequent memory effects in the occipital lobe, superior parietal lobe, and posterior cingulate cortex. In addition, older adults with more memory complaints showed a more negative subsequent memory effects in areas of the default mode network, including the posterior cingulate cortex, precuneus, and ventromedial prefrontal cortex. Our findings suggest that for successful memory formation, older adults with subjective memory complaints rely on distinct neural mechanisms which may reflect an overall decreased task-directed attention. Copyright © 2017 Elsevier Inc. All rights reserved.

Thalamo-Cortical Disruption Contributes to Short-Term Memory Deficits in Patients with Medial Temporal Lobe Damage.

PubMed

Voets, Natalie L; Menke, Ricarda A L; Jbabdi, Saad; Husain, Masud; Stacey, Richard; Carpenter, Katherine; Adcock, Jane E

2015-11-01

Short-term (STM) and long-term memory (LTM) have largely been considered as separate brain systems reflecting fronto-parietal and medial temporal lobe (MTL) functions, respectively. This functional dichotomy has been called into question by evidence of deficits on aspects of working memory in patients with MTL damage, suggesting a potentially direct hippocampal contribution to STM. As the hippocampus has direct anatomical connections with the thalamus, we tested the hypothesis that damage to thalamic nuclei regulating cortico-cortical interactions may contribute to STM deficits in patients with hippocampal dysfunction. We used diffusion-weighted magnetic resonance imaging-based tractography to identify anatomical subdivisions in patients with MTL epilepsy. From these, we measured resting-state functional connectivity with detailed cortical divisions of the frontal, temporal, and parietal lobes. Whereas thalamo-temporal functional connectivity reflected LTM performance, thalamo-prefrontal functional connectivity specifically predicted STM performance. Notably, patients with hippocampal volume loss showed thalamic volume loss, most prominent in the pulvinar region, not detected in patients with normal hippocampal volumes. Aberrant thalamo-cortical connectivity in the epileptic hemisphere was mirrored in a loss of behavioral association with STM performance specifically in patients with hippocampal atrophy. These findings identify thalamo-cortical disruption as a potential mechanism contributing to STM deficits in the context of MTL damage. © The Author 2015. Published by Oxford University Press.

Extent of resection in temporal lobectomy for epilepsy. II. Memory changes and neurologic complications.

PubMed

Katz, A; Awad, I A; Kong, A K; Chelune, G J; Naugle, R I; Wyllie, E; Beauchamp, G; Lüders, H

1989-01-01

We present correlations of extent of temporal lobectomy for intractable epilepsy with postoperative memory changes (20 cases) and abnormalities of visual field and neurologic examination (45 cases). Postoperative magnetic resonance imaging (MRI) in the coronal plane was used to quantify anteroposterior extent of resection of various quadrants of the temporal lobe, using a 20-compartment model of that structure. The Wechsler Memory Scale-Revised (WMS-R) was administered preoperatively and postoperatively. Postoperative decrease in percentage of retention of verbal material correlated with extent of medial resection of left temporal lobe, whereas decrease in percentage of retention of visual material correlated with extent of medial resection of right temporal lobe. These correlations approached but did not reach statistical significance. Extent of resection correlated significantly with the presence of visual field defect on perimetry testing but not with severity, denseness, or congruity of the defect. There was no correlation between postoperative dysphasia and extent of resection in any quadrant. Assessment of extent of resection after temporal lobectomy allows a rational interpretation of postoperative neurologic deficits in light of functional anatomy of the temporal lobe.

Replaying the game: hypnagogic images in normals and amnesics.

PubMed

Stickgold, R; Malia, A; Maguire, D; Roddenberry, D; O'Connor, M

2000-10-13

Participants playing the computer game Tetris reported intrusive, stereotypical, visual images of the game at sleep onset. Three amnesic patients with extensive bilateral medial temporal lobe damage produced similar hypnagogic reports despite being unable to recall playing the game, suggesting that such imagery may arise without important contribution from the declarative memory system. In addition, control participants reported images from previously played versions of the game, demonstrating that remote memories can influence the images from recent waking experience.

Different types of working memory binding in epilepsy patients with unilateral anterior temporal lobectomy.

PubMed

van Geldorp, Bonnie; Bouman, Zita; Hendriks, Marc P H; Kessels, Roy P C

2014-03-01

The medial temporal lobe is an important structure for long-term memory formation, but its role in working memory is less clear. Recent studies have shown hippocampal involvement during working memory tasks requiring binding of information. It is yet unclear whether this is limited to tasks containing spatial features. The present study contrasted three binding conditions and one single-item condition in patients with unilateral anterior temporal lobectomy. A group of 43 patients with temporal lobectomy (23 left; 20 right) and 20 matched controls were examined with a working memory task assessing spatial relational binding (object-location), non-spatial relational binding (object-object), conjunctive binding (object-colour) and working memory for single items. We varied the delay period (3 or 6s), as there is evidence showing that delay length may modulate working memory performance. The results indicate that performance was worse for patients than for controls in both relational binding conditions, whereas patients were unimpaired in conjunctive binding. Single-item memory was found to be marginally impaired, due to a deficit on long-delay trials only. In conclusion, working memory binding deficits are found in patients with unilateral anterior temporal lobectomy. The role of the medial temporal lobe in working memory is not limited to tasks containing spatial features. Rather, it seems to be involved in relational binding, but not in conjunctive binding. The medial temporal lobe gets involved when working memory capacity does not suffice, for example when relations have to be maintained or when the delay period is long. Copyright © 2014 Elsevier Inc. All rights reserved.

Hippocampal Networks Habituate as Novelty Accumulates

ERIC Educational Resources Information Center

Murty, Vishnu P.; Ballard, Ian C.; Macduffie, Katherine E.; Krebs, Ruth M.; Adcock, R. Alison

2013-01-01

Novelty detection, a critical computation within the medial temporal lobe (MTL) memory system, necessarily depends on prior experience. The current study used functional magnetic resonance imaging (fMRI) in humans to investigate dynamic changes in MTL activation and functional connectivity as experience with novelty accumulates. fMRI data were…

The Source for Learning & Memory Strategies.

ERIC Educational Resources Information Center

Richards, Regina G.

This book is a comprehensive guide to learning and memory strategies for all students and especially those with learning problems. Chapter 1, on memory and the brain, explains brain cells, the cortex, function of the cerebral lobes, and other brain structures. Chapter 2 examines the memory process and discusses sensory memory, short-term memory,…

What Is an Arteriovenous Malformation (AVM)?

MedlinePlus

... sensory information, such as interpretation of pain and temperature, light touch, vibration and more. The temporal lobe functions to process things related to hearing, memory, learning and receptive speech. The occipital lobe functions to ...

Memory Elicited by Courtship Conditioning Requires Mushroom Body Neuronal Subsets Similar to Those Utilized in Appetitive Memory.

PubMed

Montague, Shelby A; Baker, Bruce S

2016-01-01

An animal's ability to learn and to form memories is essential for its survival. The fruit fly has proven to be a valuable model system for studies of learning and memory. One learned behavior in fruit flies is courtship conditioning. In Drosophila courtship conditioning, male flies learn not to court females during training with an unreceptive female. He retains a memory of this training and for several hours decreases courtship when subsequently paired with any female. Courtship conditioning is a unique learning paradigm; it uses a positive-valence stimulus, a female fly, to teach a male to decrease an innate behavior, courtship of the female. As such, courtship conditioning is not clearly categorized as either appetitive or aversive conditioning. The mushroom body (MB) region in the fruit fly brain is important for several types of memory; however, the precise subsets of intrinsic and extrinsic MB neurons necessary for courtship conditioning are unknown. Here, we disrupted synaptic signaling by driving a shibirets effector in precise subsets of MB neurons, defined by a collection of split-GAL4 drivers. Out of 75 lines tested, 32 showed defects in courtship conditioning memory. Surprisingly, we did not have any hits in the γ lobe Kenyon cells, a region previously implicated in courtship conditioning memory. We did find that several γ lobe extrinsic neurons were necessary for courtship conditioning memory. Overall, our memory hits in the dopaminergic neurons (DANs) and the mushroom body output neurons were more consistent with results from appetitive memory assays than aversive memory assays. For example, protocerebral anterior medial DANs were necessary for courtship memory, similar to appetitive memory, while protocerebral posterior lateral 1 (PPL1) DANs, important for aversive memory, were not needed. Overall, our results indicate that the MB circuits necessary for courtship conditioning memory coincide with circuits necessary for appetitive memory.

Memory Elicited by Courtship Conditioning Requires Mushroom Body Neuronal Subsets Similar to Those Utilized in Appetitive Memory

PubMed Central

Montague, Shelby A.; Baker, Bruce S.

2016-01-01

An animal’s ability to learn and to form memories is essential for its survival. The fruit fly has proven to be a valuable model system for studies of learning and memory. One learned behavior in fruit flies is courtship conditioning. In Drosophila courtship conditioning, male flies learn not to court females during training with an unreceptive female. He retains a memory of this training and for several hours decreases courtship when subsequently paired with any female. Courtship conditioning is a unique learning paradigm; it uses a positive-valence stimulus, a female fly, to teach a male to decrease an innate behavior, courtship of the female. As such, courtship conditioning is not clearly categorized as either appetitive or aversive conditioning. The mushroom body (MB) region in the fruit fly brain is important for several types of memory; however, the precise subsets of intrinsic and extrinsic MB neurons necessary for courtship conditioning are unknown. Here, we disrupted synaptic signaling by driving a shibirets effector in precise subsets of MB neurons, defined by a collection of split-GAL4 drivers. Out of 75 lines tested, 32 showed defects in courtship conditioning memory. Surprisingly, we did not have any hits in the γ lobe Kenyon cells, a region previously implicated in courtship conditioning memory. We did find that several γ lobe extrinsic neurons were necessary for courtship conditioning memory. Overall, our memory hits in the dopaminergic neurons (DANs) and the mushroom body output neurons were more consistent with results from appetitive memory assays than aversive memory assays. For example, protocerebral anterior medial DANs were necessary for courtship memory, similar to appetitive memory, while protocerebral posterior lateral 1 (PPL1) DANs, important for aversive memory, were not needed. Overall, our results indicate that the MB circuits necessary for courtship conditioning memory coincide with circuits necessary for appetitive memory. PMID:27764141

Stimulation of the human medial temporal lobe between learning and recall selectively enhances forgetting.

PubMed

Merkow, Maxwell B; Burke, John F; Ramayya, Ashwin G; Sharan, Ashwini D; Sperling, Michael R; Kahana, Michael J

Direct electrical stimulation applied to the human medial temporal lobe (MTL) typically disrupts performance on memory tasks, however, the mechanism underlying this effect is not known. To study the effects of MTL stimulation on memory performance. We studied the effects of MTL stimulation on memory in five patients undergoing invasive electrocorticographic monitoring during various phases of a memory task (encoding, distractor, recall). We found that MTL stimulation disrupted memory performance in a timing-dependent manner; we observed greater forgetting when applying stimulation during the delay between encoding and recall, compared to when it was applied during encoding or recall. The results suggest that recall is most dependent on the MTL between learning and retrieval. Copyright © 2017 Elsevier Inc. All rights reserved.

Neuropsychological results after gamma knife radiosurgery for mesial temporal lobe epilepsy.

PubMed

Vojtěch, Zdeněk; Krámská, Lenka; Malíková, Hana; Stará, Michaela; Liščák, Roman

2015-01-01

The aim of this study is to summarize our experience with neuropsychological changes after radiosurgical treatment for mesial temporal lobe epilepsy and subsequent surgery due to insufficient seizure control. Between November 1995 and May 1999, 14 patients underwent radiosurgical entorhinoamygdalohippocampectomy with a marginal dose of 18, 20 or 25 Gy to the 50% isodose. 9 of these patients subsequently underwent surgery. We compared Memory Quotients and Intelligence Quotients before and after the interventions. We found a slight, but nonsignificant decline in intelligence and memory quotients one year after GKRS. Two years after radiosurgery there were no significant changes in any of the quotients. After surgery, we found significant increase in Global and Visual MQ, (p<0.05). There were no statistically significant changes in verbal memory and intelligence performance after surgery. Epilepsy surgery after unsuccessful radiosurgery could lead to improvements in cognitive functions in patients with mesial temporal lobe epilepsy.

The Episodic Memory System: Neurocircuitry and Disorders

PubMed Central

Dickerson, Bradford C; Eichenbaum, Howard

2010-01-01

The ability to encode and retrieve our daily personal experiences, called episodic memory, is supported by the circuitry of the medial temporal lobe (MTL), including the hippocampus, which interacts extensively with a number of specific distributed cortical and subcortical structures. In both animals and humans, evidence from anatomical, neuropsychological, and physiological studies indicates that cortical components of this system have key functions in several aspects of perception and cognition, whereas the MTL structures mediate the organization and persistence of the network of memories whose details are stored in those cortical areas. Structures within the MTL, and particularly the hippocampus, have distinct functions in combining information from multiple cortical streams, supporting our ability to encode and retrieve details of events that compose episodic memories. Conversely, selective damage in the hippocampus, MTL, and other structures of the large-scale memory system, or deterioration of these areas in several diseases and disorders, compromises episodic memory. A growing body of evidence is converging on a functional organization of the cortical, subcortical, and MTL structures that support the fundamental features of episodic memory in humans and animals. PMID:19776728

Factors affecting reorganisation of memory encoding networks in temporal lobe epilepsy

PubMed Central

Sidhu, M.K.; Stretton, J.; Winston, G.P.; Symms, M.; Thompson, P.J.; Koepp, M.J.; Duncan, J.S.

2015-01-01

Summary Aims In temporal lobe epilepsy (TLE) due to hippocampal sclerosis reorganisation in the memory encoding network has been consistently described. Distinct areas of reorganisation have been shown to be efficient when associated with successful subsequent memory formation or inefficient when not associated with successful subsequent memory. We investigated the effect of clinical parameters that modulate memory functions: age at onset of epilepsy, epilepsy duration and seizure frequency in a large cohort of patients. Methods We studied 53 patients with unilateral TLE and hippocampal sclerosis (29 left). All participants performed a functional magnetic resonance imaging memory encoding paradigm of faces and words. A continuous regression analysis was used to investigate the effects of age at onset of epilepsy, epilepsy duration and seizure frequency on the activation patterns in the memory encoding network. Results Earlier age at onset of epilepsy was associated with left posterior hippocampus activations that were involved in successful subsequent memory formation in left hippocampal sclerosis patients. No association of age at onset of epilepsy was seen with face encoding in right hippocampal sclerosis patients. In both left hippocampal sclerosis patients during word encoding and right hippocampal sclerosis patients during face encoding, shorter duration of epilepsy and lower seizure frequency were associated with medial temporal lobe activations that were involved in successful memory formation. Longer epilepsy duration and higher seizure frequency were associated with contralateral extra-temporal activations that were not associated with successful memory formation. Conclusion Age at onset of epilepsy influenced verbal memory encoding in patients with TLE due to hippocampal sclerosis in the speech-dominant hemisphere. Shorter duration of epilepsy and lower seizure frequency were associated with less disruption of the efficient memory encoding network whilst longer duration and higher seizure frequency were associated with greater, inefficient, extra-temporal reorganisation. PMID:25616449

Calibrated fMRI in the Medial Temporal Lobe During a Memory Encoding Task

PubMed Central

Restom, Khaled; Perthen, Joanna E.; Liu, Thomas T.

2008-01-01

Prior measures of the blood oxygenation level dependent (BOLD) and cerebral blood flow (CBF) responses to a memory encoding task within the medial temporal lobe have suggested that the coupling between functional changes in CBF and changes in the cerebral metabolic rate of oxgyen (CMRO2) may be tighter in the medial temporal lobe as compared to the primary sensory areas. In this study, we used a calibrated functional magnetic resonance imaging (fMRI) approach to directly estimate memory-encoding-related changes in CMRO2 and to assess the coupling between CBF and CMRO2 in the medial temporal lobe. The CBF-CMRO2 coupling ratio was estimated using a linear fit to the flow and metabolism changes observed across subjects. In addition, we examined the effect of region-of-interest (ROI) selection on the estimates. In response to the memory encoding task, CMRO2 increased by 23.1% ± 8.8 to 25.3% ± 5.7 (depending upon ROI), with an estimated CBF-CMRO2 coupling ratio of 1.66 ± 0.07 to 1.75± 0.16. There was not a significant effect of ROI selection on either the CMRO2 or coupling ratio estimates. The observed coupling ratios were significantly lower than the values (2 to 4.5) that have been reported in previous calibrated fMRI studies of the visual and motor cortices. In addition, the estimated coupling ratio was found to be less sensitive to the calibration procedure for functional responses in the medial temporal lobe as compared to the primary sensory areas. PMID:18329291

Spatial Working Memory Impairment in Patients with Non-neuropsychiatric Systemic Lupus Erythematosus: A Blood-oxygen-level Dependent Functional Magnetic Resonance Imaging Study.

PubMed

Zhu, Chun-Min; Ma, Ye; Xie, Lei; Huang, Jin-Zhuang; Sun, Zong-Bo; Duan, Shou-Xing; Lin, Zhi-Rong; Yin, Jing-Jing; Le, Hong-Bo; Sun, Dan-Miao; Xu, Wen-Can; Ma, Shu-Hua

2017-02-01

Using ethology and functional magnetic resonance imaging (fMRI) to explore mild cognitive dysfunction and spatial working memory (WM) impairment in patients with systemic lupus erythematosus (SLE) without overt neuropsychiatric symptoms (non-NPSLE) and to study whether any clinical biomarkers could serve as predictors of brain dysfunction in this disease. Eighteen non-NPSLE patients and 18 matched subjects were all tested using the Montreal cognitive assessment scale test and scanned using blood-oxygen-level dependent fMRI while performing the n-back task to investigate the activation intensity of some cognition-related areas. Ethology results showed that non-NPSLE patients had mild cognitive dysfunction and memory dysfunction (p < 0.05). The fMRI scan confirmed a neural network consisting of bilateral dorsolateral prefrontal cortex (DLPFC), premotor area, parietal lobe, and supplementary motor area (SMA)/anterior cingulate cortex (ACC) that was activated during the n-back task, with right hemisphere dominance. However, only the right SMA/ACC showed a load effect in the non-NPSLE group; the activation intensity of most WM-related brain areas for the non-NPSLE group was lower than for the control group under 3 memory loads. Further, we found that the activation intensity of some cognition-related areas, including the bilateral caudate nucleus/insula and hippocampus/parahippocampal gyrus were lower than the control group under the memory loads. An inverse correlation existed between individual activation intensity and disease duration. Non-NPSLE-related brain damage with right DLPFC-posterior parietal lobe and parahippocampal gyrus default network causes impairment of spatial WM and mild cognitive dysfunction. Patients with longer disease duration would be expected to exhibit increased central nervous system damage.

Pre- and long-term postoperative courses of hippocampus-associated memory impairment in epilepsy patients with antibody-associated limbic encephalitis and selective amygdalohippocampectomy.

PubMed

Hansen, Niels; Ernst, Leon; Rüber, Theodor; Widman, Guido; Becker, Albert J; Elger, Christian E; Helmstaedter, Christoph

2018-02-01

Limbic encephalitis (LE) is defined by mesiotemporal lobe structure abnormalities, seizures, memory, and psychiatric disturbances. This study aimed to identify the long-term clinical and neuropsychological outcome of selective amygdalohippocampectomy (sAH) in drug-resistant patients with temporal lobe epilepsy due to known or later diagnosed subacute LE not responding to immunotherapy associated with neuronal autoantibodies. In seven patients with temporal lobe epilepsy due to antibody positive LE (glutamic acid decarboxylase (GAD65): n=5; voltage-gated potassium channel complex (VGKC), N-methyl d-aspartate receptor (NMDAR): n=1; Ma-2/Ta: n=1) sAH (6 left, 1 right) was performed. Those patients underwent repeated electroencephalography (EEG) recordings, magnetic resonance imaging (MRI) volumetry of the amygdala and hippocampus, and neuropsychological examinations and were followed up for 6-7years on average. Verbal memory and figural memory were affected in 57% of patients at baseline and 71% at the last follow-up. At the last follow-up, 14% of the patients had declined in verbal memory and figural memory. We observed improved memory in 43% of patients regarding figural memory, but not in a single patient regarding verbal memory. Repeated evaluations across the individual courses reveal cognitive and MRI dynamics that appear to be unrelated to surgery and drug treatment. Three of the seven patients with LE with different antibodies (NMDAR: n=1, Ma-2/Ta: n=1 and GAD65: n=1) achieved persistent seizure freedom along with no accelerated memory decline after surgery. Two of the five GAD65-antibody patients positive with LE showed progressive memory decline and a long-term tendency to contralateral hippocampus atrophy. While memory demonstrated some decline in the long run, what is most important is that a progressive decline in memory is seldom found after sAH in patients with LE. Moreover, the dynamics in performance and MRI before and after surgery reveal disease dynamics independent of surgery. Selective amygdalohippocampectomy can lead to seizure freedom, but should be considered as a last resort treatment option for drug-resistant patients with temporal lobe epilepsy due to LE. Particular caution is recommended in patients with GAD65-LE. Copyright © 2017 Elsevier Inc. All rights reserved.

Bringing memory fMRI to the clinic: comparison of seven memory fMRI protocols in temporal lobe epilepsy.

PubMed

Towgood, Karren; Barker, Gareth J; Caceres, Alejandro; Crum, William R; Elwes, Robert D C; Costafreda, Sergi G; Mehta, Mitul A; Morris, Robin G; von Oertzen, Tim J; Richardson, Mark P

2015-04-01

fMRI is increasingly implemented in the clinic to assess memory function. There are multiple approaches to memory fMRI, but limited data on advantages and reliability of different methods. Here, we compared effect size, activation lateralisation, and between-sessions reliability of seven memory fMRI protocols: Hometown Walking (block design), Scene encoding (block design and event-related design), Picture encoding (block and event-related), and Word encoding (block and event-related). All protocols were performed on three occasions in 16 patients with temporal lobe epilepsy (TLE). Group T-maps showed activity bilaterally in medial temporal lobe for all protocols. Using ANOVA, there was an interaction between hemisphere and seizure-onset lateralisation (P = 0.009) and between hemisphere, protocol and seizure-onset lateralisation (P = 0.002), showing that the distribution of memory-related activity between left and right temporal lobes differed between protocols and between patients with left-onset and right-onset seizures. Using voxelwise intraclass Correlation Coefficient, between-sessions reliability was best for Hometown and Scenes (block and event). The between-sessions spatial overlap of activated voxels was also greatest for Hometown and Scenes. Lateralisation of activity between hemispheres was most reliable for Scenes (block and event) and Words (event). Using receiver operating characteristic analysis to explore the ability of each fMRI protocol to classify patients as left-onset or right-onset TLE, only the Words (event) protocol achieved a significantly above-chance classification of patients at all three sessions. We conclude that Words (event) protocol shows the best combination of between-sessions reliability of the distribution of activity between hemispheres and reliable ability to distinguish between left-onset and right-onset patients. © 2015 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

Striatal contributions to declarative memory retrieval

PubMed Central

Scimeca, Jason M.; Badre, David

2012-01-01

Declarative memory is known to depend on the medial temporal lobe memory system. Recently, there has been renewed focus on the relationship between the basal ganglia and declarative memory, including the involvement of striatum. However, the contribution of striatum to declarative memory retrieval remains unknown. Here, we review neuroimaging and neuropsychological evidence for the involvement of the striatum in declarative memory retrieval. From this review, we propose that, along with the prefrontal cortex (PFC), the striatum primarily supports cognitive control of memory retrieval. We conclude by proposing three hypotheses for the specific role of striatum in retrieval: (1) Striatum modulates the re-encoding of retrieved items in accord with their expected utility (adaptive encoding), (2) striatum selectively admits information into working memory that is expected to increase the likelihood of successful retrieval (adaptive gating), and (3) striatum enacts adjustments in cognitive control based on the outcome of retrieval (reinforcement learning). PMID:22884322

Medial temporal lobe atrophy relates more strongly to sleep-wake rhythm fragmentation than to age or any other known risk.

PubMed

Van Someren, Eus J W; Oosterman, J M; Van Harten, B; Vogels, R L; Gouw, A A; Weinstein, H C; Poggesi, A; Scheltens, Ph; Scherder, E J A

2018-06-01

Atrophy of the medial temporal lobe of the brain is key to memory function and memory complaints in old age. While age and some morbidities are major risk factors for medial temporal lobe atrophy, individual differences remain, and mechanisms are insufficiently known. The largest combined neuroimaging and whole genome study to date indicates that medial temporal lobe volume is most associated with common polymorphisms in the GRIN2B gene that encodes for the 2B subunit (NR2B) of the NMDA receptor. Because sleep disruption induces a selective loss of NR2B from hippocampal synaptic membranes in rodents, and because of several other reports on medial temporal lobe sensitivity to sleep disruption, we hypothesized a contribution of the typical age-related increase in sleep-wake rhythm fragmentation to medial temporal lobe atrophy. Magnetic resonance imaging and actigraphy in 138 aged individuals showed that individual differences in sleep-wake rhythm fragmentation accounted for more (19%) of the variance in medial temporal lobe atrophy than age did (15%), or any of a list of health and brain structural indicators. The findings suggest a role of sleep-wake rhythm fragmentation in age-related medial temporal lobe atrophy, that might in part be prevented or reversible. Copyright © 2018. Published by Elsevier Inc.

Dopamine- and Tyrosine Hydroxylase-Immunoreactive Neurons in the Brain of the American Cockroach, Periplaneta americana

PubMed Central

Hamanaka, Yoshitaka; Minoura, Run; Nishino, Hiroshi; Miura, Toru; Mizunami, Makoto

2016-01-01

The catecholamine dopamine plays several vital roles in the central nervous system of many species, but its neural mechanisms remain elusive. Detailed neuroanatomical characterization of dopamine neurons is a prerequisite for elucidating dopamine’s actions in the brain. In the present study, we investigated the distribution of dopaminergic neurons in the brain of the American cockroach, Periplaneta americana, using two antisera: 1) an antiserum against dopamine, and 2) an antiserum against tyrosine hydroxylase (TH, an enzyme required for dopamine synthesis), and identified about 250 putatively dopaminergic neurons. The patterns of dopamine- and TH-immunoreactive neurons were strikingly similar, suggesting that both antisera recognize the same sets of “dopaminergic” neurons. The dopamine and TH antibodies intensively or moderately immunolabeled prominent brain neuropils, e.g. the mushroom body (memory center), antennal lobe (first-order olfactory center) and central complex (motor coordination center). All subdivisions of the mushroom body exhibit both dopamine and TH immunoreactivity. Comparison of immunolabeled neurons with those filled by dye injection revealed that a group of immunolabeled neurons with cell bodies near the calyx projects into a distal region of the vertical lobe, which is a plausible site for olfactory memory formation in insects. In the antennal lobe, ordinary glomeruli as well as macroglomeruli exhibit both dopamine and TH immunoreactivity. It is noteworthy that the dopamine antiserum labeled tiny granular structures inside the glomeruli whereas the TH antiserum labeled processes in the marginal regions of the glomeruli, suggesting a different origin. In the central complex, all subdivisions excluding part of the noduli and protocerebral bridge exhibit both dopamine and TH immunoreactivity. These anatomical findings will accelerate our understanding of dopaminergic systems, specifically in neural circuits underlying aversive memory formation and arousal, in insects. PMID:27494326

Deep processing activates the medial temporal lobe in young but not in old adults.

PubMed

Daselaar, Sander M; Veltman, Dick J; Rombouts, Serge A R B; Raaijmakers, Jeroen G W; Jonker, Cees

2003-11-01

Age-related impairments in episodic memory have been related to a deficiency in semantic processing, based on the finding that elderly adults typically benefit less than young adults from deep, semantic as opposed to shallow, nonsemantic processing of study items. In the present study, we tested the hypothesis that elderly adults are not able to perform certain cognitive operations under deep processing conditions. We further hypothesised that this inability does not involve regions commonly associated with lexical/semantic retrieval processes, but rather involves a dysfunction of the medial temporal lobe (MTL) memory system. To this end, we used functional MRI on rather extensive groups of young and elderly adults to compare brain activity patterns obtained during a deep (living/nonliving) and a shallow (uppercase/lowercase) classification task. Common activity in relation to semantic classification was observed in regions that have been previously related to semantic retrieval, including mainly left-lateralised activity in the inferior prefrontal, middle temporal, and middle frontal/anterior cingulate gyrus. Although the young adults showed more activity in some of these areas, the finding of mainly overlapping activation patterns during semantic classification supports the idea that lexical/semantic retrieval processes are still intact in elderly adults. This received further support by the finding that both groups showed similar behavioural performances as well on the deep and shallow classification tasks. Importantly, though, the young revealed significantly more activity than the elderly adults in the left anterior hippocampus during deep relative to shallow classification. This finding is in line with the idea that age-related impairments in episodic encoding are, at least partly, due to an under-recruitment of the medial temporal lobe memory system.

Functional MR imaging or Wada test: which is the better predictor of individual postoperative memory outcome?

PubMed

Dupont, Sophie; Duron, Emmanuelle; Samson, Séverine; Denos, Marisa; Volle, Emmanuelle; Delmaire, Christine; Navarro, Vincent; Chiras, Jacques; Lehéricy, Stéphane; Samson, Yves; Baulac, Michel

2010-04-01

To retrospectively determine whether blood oxygen level-dependent functional magnetic resonance (MR) imaging can aid prediction of postoperative memory changes in epileptic patients after temporal lobe surgery. This study was approved by the local ethics committee, and informed consent was obtained from all patients. Data were analyzed from 25 patients (12 women, 13 men; age range, 19-52 years) with refractory epilepsy in whom temporal lobe surgery was performed after they underwent preoperative functional MR imaging, the Wada test, and neuropsychological testing. The functional MR imaging protocol included three different memory tasks (24-hour delayed recognition, encoding, and immediate recognition). Individual activations were measured in medial temporal lobe (MTL) regions of both hemispheres. The prognostic accuracy of functional MR imaging for prediction of postoperative memory changes was compared with the accuracy of the Wada test and preoperative neuropsychological testing by using a backward multiple regression analysis. An equation that was based on left functional MR imaging MTL activation during delayed recognition, side of the epileptic focus, and preoperative global verbal memory score was used to correctly predict worsening of verbal memory in 90% of patients. The right functional MR imaging MTL activation did not substantially correlate with the nonverbal memory outcome, which was only predicted by using the preoperative nonverbal global score. Wada test data were not good predictors of changes in either verbal or nonverbal memory. Findings suggest that functional MR imaging activation during a delayed-recognition task is a better predictor of individual postoperative verbal memory outcome than is the Wada test. RSNA, 2010

Entorhinal Tau Pathology, Episodic Memory Decline, and Neurodegeneration in Aging.

PubMed

Maass, Anne; Lockhart, Samuel N; Harrison, Theresa M; Bell, Rachel K; Mellinger, Taylor; Swinnerton, Kaitlin; Baker, Suzanne L; Rabinovici, Gil D; Jagust, William J

2018-01-17

The medial temporal lobe (MTL) is an early site of tau accumulation and MTL dysfunction may underlie episodic-memory decline in aging and dementia. Postmortem data indicate that tau pathology in the transentorhinal cortex is common by age 60, whereas spread to neocortical regions and worsening of cognition is associated with β-amyloid (Aβ). We used [ 18 F]AV-1451 and [ 11 C]PiB positron emission tomography, structural MRI, and neuropsychological assessment to investigate how in vivo tau accumulation in temporal lobe regions, Aβ, and MTL atrophy contribute to episodic memory in cognitively normal older adults ( n = 83; age, 77 ± 6 years; 58% female). Stepwise regressions identified tau in MTL regions known to be affected in old age as the best predictor of episodic-memory performance independent of Aβ status. There was no interactive effect of MTL tau with Aβ on memory. Higher MTL tau was related to higher age in the subjects without evidence of Aβ. Among temporal lobe subregions, episodic memory was most strongly related to tau-tracer uptake in the parahippocampal gyrus, particularly the posterior entorhinal cortex, which in our parcellation includes the transentorhinal cortex. In subjects with longitudinal MRI and cognitive data ( n = 57), entorhinal atrophy mirrored patterns of tau pathology and their relationship with memory decline. Our data are consistent with neuropathological studies and further suggest that entorhinal tau pathology underlies memory decline in old age even without Aβ. SIGNIFICANCE STATEMENT Tau tangles and β-amyloid (Aβ) plaques are key lesions in Alzheimer's disease (AD) but both pathologies also occur in cognitively normal older people. Neuropathological data indicate that tau tangles in the medial temporal lobe (MTL) underlie episodic-memory impairments in AD dementia. However, it remains unclear whether MTL tau pathology also accounts for memory impairments often seen in elderly people and how Aβ affects this relationship. Using tau-specific and Aβ-specific positron emission tomography tracers, we show that in vivo MTL tau pathology is associated with episodic-memory performance and MTL atrophy in cognitively normal adults, independent of Aβ. Our data point to MTL tau pathology, particularly in the entorhinal cortex, as a substrate of age-related episodic-memory loss. Copyright © 2018 the authors 0270-6474/18/380530-14$15.00/0.

The role of medial temporal lobe in retrieving spatial and nonspatial relations from episodic and semantic memory.

PubMed

Ryan, Lee; Lin, Chun-Yu; Ketcham, Katie; Nadel, Lynn

2010-01-01

This study examined the involvement of medial temporal lobe, especially the hippocampus, in processing spatial and nonspatial relations using episodic and semantic versions of a relational judgment task. Participants studied object arrays and were tested on different types of relations between pairs of objects. Three prevalent views of hippocampal function were considered. Cognitive map theory (O'Keefe and Nadel (1978) The Hippocampus as a Cognitive Map. USA: Oxford University Press) emphasizes hippocampal involvement in spatial relational tasks. Multiple trace theory (Nadel and Moscovitch (1997) Memory consolidation, retrograde amnesia and the hippocampal complex Curr Opin Neurobiol 7:217-227) emphasizes hippocampal involvement in episodic tasks. Eichenbaum and Cohen's ((2001) From Conditioning to Conscious Recollection: Memory Systems of the Brain. USA: Oxford University Press) relational theory predicts equivalent hippocampal involvement in all relational tasks within both semantic and episodic memory. The fMRI results provided partial support for all three theories, though none of them fit the data perfectly. We observed hippocampal activation during all relational tasks, with increased activation for spatial compared to nonspatial relations, and for episodic compared to semantic relations. The placement of activation along the anterior-posterior axis of the hippocampus also differentiated the conditions. We suggest a view of hippocampal function in memory that incorporates aspects of all three theories. Copyright 2009 Wiley-Liss, Inc.

Accelerated cognitive decline in a rodent model for temporal lobe epilepsy.

PubMed

Schipper, Sandra; Aalbers, Marlien W; Rijkers, Kim; Lagiere, Melanie; Bogaarts, Jan G; Blokland, Arjan; Klinkenberg, Sylvia; Hoogland, Govert; Vles, Johan S H

2016-12-01

Cognitive impairment is frequently observed in patients with temporal lobe epilepsy. It is hypothesized that cumulative seizure exposure causes accelerated cognitive decline in patients with epilepsy. We investigated the influence of seizure frequency on cognitive decline in a rodent model for temporal lobe epilepsy. Neurobehavioral assessment was performed before and after surgery, after the induction of self-sustaining limbic status epilepticus (SSLSE), and in the chronic phase in which rats experienced recurrent seizures. Furthermore, we assessed potential confounders of memory performance. Rats showed a deficit in spatial working memory after the induction of the SSLSE, which endured in the chronic phase. A progressive decline in recognition memory developed in SSLSE rats. Confounding factors were absent. Seizure frequency and also the severity of the status epilepticus were not correlated with the severity of cognitive deficits. The effect of the seizure frequency on cognitive comorbidity in epilepsy has long been debated, possibly because of confounders such as antiepileptic medication and the heterogeneity of epileptic etiologies. In an animal model of temporal lobe epilepsy, we showed that a decrease in spatial working memory does not relate to the seizure frequency. This suggests for other mechanisms are responsible for memory decline and potentially a common pathophysiology of cognitive deterioration and the occurrence and development of epileptic seizures. Identifying this common denominator will allow development of more targeted interventions treating cognitive decline in patients with epilepsy. The treatment of interictal symptoms will increase the quality of life of many patients with epilepsy. Copyright © 2016 Elsevier Inc. All rights reserved.

Neuroanatomy of episodic and semantic memory in humans: a brief review of neuroimaging studies.

PubMed

García-Lázaro, Haydée G; Ramirez-Carmona, Rocio; Lara-Romero, Ruben; Roldan-Valadez, Ernesto

2012-01-01

One of the most basic functions in every individual and species is memory. Memory is the process by which information is saved as knowledge and retained for further use as needed. Learning is a neurobiological phenomenon by which we acquire certain information from the outside world and is a precursor to memory. Memory consists of the capacity to encode, store, consolidate, and retrieve information. Recently, memory has been defined as a network of connections whose function is primarily to facilitate the long-lasting persistence of learned environmental cues. In this review, we present a brief description of the current classifications of memory networks with a focus on episodic memory and its anatomical substrate. We also present a brief review of the anatomical basis of memory systems and the most commonly used neuroimaging methods to assess memory, illustrated with magnetic resonance imaging images depicting the hippocampus, temporal lobe, and hippocampal formation, which are the main brain structures participating in memory networks.

Domain-specific impairment of source memory following a right posterior medial temporal lobe lesion.

PubMed

Peters, Jan; Koch, Benno; Schwarz, Michael; Daum, Irene

2007-01-01

This single case analysis of memory performance in a patient with an ischemic lesion affecting posterior but not anterior right medial temporal lobe (MTL) indicates that source memory can be disrupted in a domain-specific manner. The patient showed normal recognition memory for gray-scale photos of objects (visual condition) and spoken words (auditory condition). While memory for visual source (texture/color of the background against which pictures appeared) was within the normal range, auditory source memory (male/female speaker voice) was at chance level, a performance pattern significantly different from the control group. This dissociation is consistent with recent fMRI evidence of anterior/posterior MTL dissociations depending upon the nature of source information (visual texture/color vs. auditory speaker voice). The findings are in good agreement with the view of dissociable memory processing by the perirhinal cortex (anterior MTL) and parahippocampal cortex (posterior MTL), depending upon the neocortical input that these regions receive. (c) 2007 Wiley-Liss, Inc.

Persistently active neurons in human medial frontal and medial temporal lobe support working memory

PubMed Central

Kamiński, J; Sullivan, S; Chung, JM; Ross, IB; Mamelak, AN; Rutishauser, U

2017-01-01

Persistent neural activity is a putative mechanism for the maintenance of working memories. Persistent activity relies on the activity of a distributed network of areas, but the differential contribution of each area remains unclear. We recorded single neurons in the human medial frontal cortex and the medial temporal lobe while subjects held up to three items in memory. We found persistently active neurons in both areas. Persistent activity of hippocampal and amygdala neurons was stimulus-specific, formed stable attractors, and was predictive of memory content. Medial frontal cortex persistent activity, on the other hand, was modulated by memory load and task set but was not stimulus-specific. Trial-by-trial variability in persistent activity in both areas was related to memory strength, because it predicted the speed and accuracy by which stimuli were remembered. This work reveals, in humans, direct evidence for a distributed network of persistently active neurons supporting working memory maintenance. PMID:28218914

Epilepsy increases vulnerability of long-term face recognition to proactive interference.

PubMed

Bengner, T; Malina, T; Lindenau, M; Voges, B; Goebell, E; Stodieck, S

2006-02-01

Proactive interference (PI) decreases short- and long-term memory in healthy subjects. Neurological patients exhibit a heightened PI effect on short-term memory. It is, however, not known if PI affects long-term memory in neurological patients. We analyzed whether epilepsy heightens the negative effect of PI on long-term face memory. PI was induced by a list of 20 faces learned 24 hours prior to a target list of 20 faces. We tested immediate and 24-hour recognition for both lists. Twelve healthy controls and 42 patients with generalized epilepsy or temporal lobe epilepsy (TLE) were studied. PI led to a decrease in 24-hour recognition in patients with generalized epilepsy and TLE but not in controls. Thus, PI may cause long-term memory disturbances in epilepsy patients. PI was also associated with decreased short-term memory, but only in right TLE. This confirms the dominant role of the right temporal lobe in short-term face memory.

Recovering and Preventing Loss of Detailed Memory: Differential Rates of Forgetting for Detail Types in Episodic Memory

ERIC Educational Resources Information Center

Sekeres, Melanie J.; Bonasia, Kyra; St-Laurent, Marie; Pishdadian, Sara; Winocur, Gordon; Grady, Cheryl; Moscovitch, Morris

2016-01-01

Episodic memories undergo qualitative changes with time, but little is known about how different aspects of memory are affected. Different types of information in a memory, such as perceptual detail, and central themes, may be lost at different rates. In patients with medial temporal lobe damage, memory for perceptual details is severely impaired,…

Verbal memory decline from hippocampal depth electrodes in temporal lobe surgery for epilepsy.

PubMed

Ljung, Hanna; Nordlund, Arto; Strandberg, Maria; Bengzon, Johan; Källén, Kristina

2017-12-01

To explore whether patients with refractory mesial temporal lobe epilepsy risk aggravated verbal memory loss from intracranial electroencephalography (EEG) recording with longitudinal hippocampal electrodes in the language-dominant hemisphere. A long-term neuropsychological follow-up (mean 61.5 months, range 22-111 months) was performed in 40 patients after ictal registration with left hippocampal depth electrodes (study group, n = 16) or no invasive EEG, only extracranial registration (reference group, n = 24). The groups were equal with respect to education, age at seizure onset, epilepsy duration, and prevalence of pharmacoresistant temporal lobe epilepsy (TLE; 75%) versus seizure freedom (25%). Retrospective neuropsychological data from preoperative surgical workup (T1) and prospective follow-up neuropsychological data (T2) were compared. A ≥1 SD intrapatient decline was considered as clinically relevant deterioration of verbal memory. Significant decline in verbal memory was seen in 56% of the patients in the study group compared to 21% in the reference group. At T1, there were no statistical between-group differences in memory performance. At T2, between-group comparison showed significantly greater verbal memory decline for the study group (Claeson Dahl Learning and Retention Test, Verbal Learning: p = 0.05; Rey Auditory Verbal Learning Test, Total Learning: p = 0.04; Claeson Dahl Learning and Retention Test, Verbal Retention: p = 0.04). An odds ratio (OR) of 7.1 (90% confidence interval [CI] 1.3-37.7) for verbal memory decline was seen if right temporal lobe resection (R TLR) had been performed between T1 and T2. The difference between groups remained unchanged when patients who had undergone R TLR were excluded from the analysis, with a remaining aggravated significant decline in verbal memory performance for the study group compared to the reference group. Our results suggest a risk of verbal memory deterioration after the use of depth electrodes along the longitudinal axis of the hippocampus. Until this issue is further investigated, caution regarding depth electrodes in the language-dominant hemisphere hippocampus seems advisable. Wiley Periodicals, Inc. © 2017 International League Against Epilepsy.

Explaining how brain stimulation can evoke memories.

PubMed

Jacobs, Joshua; Lega, Bradley; Anderson, Christopher

2012-03-01

An unexplained phenomenon in neuroscience is the discovery that electrical stimulation in temporal neocortex can cause neurosurgical patients to spontaneously experience memory retrieval. Here we provide the first detailed examination of the neural basis of stimulation-induced memory retrieval by probing brain activity in a patient who reliably recalled memories of his high school (HS) after stimulation at a site in his left temporal lobe. After stimulation, this patient performed a customized memory task in which he was prompted to retrieve information from HS and non-HS topics. At the one site where stimulation evoked HS memories, remembering HS information caused a distinctive pattern of neural activity compared with retrieving non-HS information. Together, these findings suggest that the patient had a cluster of neurons in his temporal lobe that help represent the "high school-ness" of the current cognitive state. We believe that stimulation here evoked HS memories because it altered local neural activity in a way that partially mimicked the normal brain state for HS memories. More broadly, our findings suggest that brain stimulation can evoke memories by recreating neural patterns from normal cognition.

Hippocampus at 25

PubMed Central

Eichenbaum, Howard; Amaral, David G.; Buffalo, Elizabeth A.; Buzsáki, György; Cohen, Neal; Davachi, Lila; Frank, Loren; Heckers, Stephan; Morris, Richard G. M.; Moser, Edvard I.; Nadel, Lynn; O'Keefe, John; Preston, Alison; Ranganath, Charan; Silva, Alcino; Witter, Menno

2017-01-01

The journal Hippocampus has passed the milestone of 25 years of publications on the topic of a highly studied brain structure, and its closely associated brain areas. In a recent celebration of this event, a Boston memory group invited 16 speakers to address the question of progress in understanding the hippocampus that has been achieved. Here we present a summary of these talks organized as progress on four main themes: (1) Understanding the hippocampus in terms of its interactions with multiple cortical areas within the medial temporal lobe memory system, (2) understanding the relationship between memory and spatial information processing functions of the hippocampal region, (3) understanding the role of temporal organization in spatial and memory processing by the hippocampus, and (4) understanding how the hippocampus integrates related events into networks of memories. PMID:27399159

Localized Fluctuant Oscillatory Activity by Working Memory Load: A Simultaneous EEG-fMRI Study.

PubMed

Zhao, Xiaojie; Li, Xiaoyun; Yao, Li

2017-01-01

Working memory (WM) is a resource-limited memory system for temporary storage and processing of brain information during the execution of cognitive tasks. Increased WM load will increase the amount and difficulty of memory information. Several studies have used electroencephalography (EEG) or functional magnetic resonance imaging (fMRI) to explore load-dependent cognition processing according to the time courses of electrophysiological activity or the spatial pattern of blood oxygen metabolic activity. However, the relationships between these two activities and the underlying neural mechanism are still unclear. In this study, using simultaneously collected EEG and fMRI data under an n-back verbal WM task, we modeled the spectral perturbation of EEG oscillation and fMRI activation through joint independent component analysis (JICA). Multi-channel oscillation features were also introduced into the JICA model for further analysis. The results showed that time-locked activity of theta and beta were modulated by memory load in the early stimuli evaluation stage, corresponding to the enhanced activation in the frontal and parietal lobe, which were involved in stimulus discrimination, information encoding and delay-period activity. In the late response selection stage, alpha and gamma activity changes dependent on the load correspond to enhanced activation in the areas of frontal, temporal and parietal lobes, which played important roles in attention, information extraction and memory retention. These findings suggest that the increases in memory load not only affect the intensity and time course of the EEG activities, but also lead to the enhanced activation of brain regions which plays different roles during different time periods of cognitive process of WM.

Effects of semantic relatedness on recall of stimuli preceding emotional oddballs.

PubMed

Smith, Ryan M; Beversdorf, David Q

2008-07-01

Semantic and episodic memory networks function as highly interconnected systems, both relying on the hippocampal/medial temporal lobe complex (HC/MTL). Episodic memory encoding triggers the retrieval of semantic information, serving to incorporate contextual relationships between the newly acquired memory and existing semantic representations. While emotional material augments episodic memory encoding at the time of stimulus presentation, interactions between emotion and semantic memory that contribute to subsequent episodic recall are not well understood. Using a modified oddball task, we examined the modulatory effects of negative emotion on semantic interactions with episodic memory by measuring the free-recall of serially presented neutral or negative words varying in semantic relatedness. We found increased free-recall for words related to and preceding emotionally negative oddballs, suggesting that negative emotion can indirectly facilitate episodic free-recall by enhancing semantic contributions during encoding. Our findings demonstrate the ability of emotion and semantic memory to interact to mutually enhance free-recall.

The neural basis of implicit learning and memory: a review of neuropsychological and neuroimaging research.

PubMed

Reber, Paul J

2013-08-01

Memory systems research has typically described the different types of long-term memory in the brain as either declarative versus non-declarative or implicit versus explicit. These descriptions reflect the difference between declarative, conscious, and explicit memory that is dependent on the medial temporal lobe (MTL) memory system, and all other expressions of learning and memory. The other type of memory is generally defined by an absence: either the lack of dependence on the MTL memory system (nondeclarative) or the lack of conscious awareness of the information acquired (implicit). However, definition by absence is inherently underspecified and leaves open questions of how this type of memory operates, its neural basis, and how it differs from explicit, declarative memory. Drawing on a variety of studies of implicit learning that have attempted to identify the neural correlates of implicit learning using functional neuroimaging and neuropsychology, a theory of implicit memory is presented that describes it as a form of general plasticity within processing networks that adaptively improve function via experience. Under this model, implicit memory will not appear as a single, coherent, alternative memory system but will instead be manifested as a principle of improvement from experience based on widespread mechanisms of cortical plasticity. The implications of this characterization for understanding the role of implicit learning in complex cognitive processes and the effects of interactions between types of memory will be discussed for examples within and outside the psychology laboratory. Copyright © 2013 Elsevier Ltd. All rights reserved.

Translational MRI volumetry with NeuroQuant: Effects of version and normative data on relationships with memory performance in healthy older adults and patients with mild cognitive impairment

PubMed Central

Stelmokas, Julija; Yassay, Lance; Giordani, Bruno; Dodge, Hiroko H.; Dinov, Ivo D.; Bhaumik, Arijit; Sathian, K.; Hampstead, Benjamin M.

2018-01-01

NeuroQuant (NQ) is a fully-automated program that overcomes several existing limitations in the clinical translation of MRI-derived volumetry. The current study characterized differences between the original (NQ1) and an updated NQ version (NQ2) by (i) replicating previously identified relationships between neuropsychological test performance and medial temporal lobe volumes, (ii) evaluating the level of agreement between NQ versions, and (iii) determining if the addition of NQ2 age-/sex-based z-scores hold greater clinical utility for prediction of memory impairment than standard percent of intracranial volume (%ICV) values. Sixty-seven healthy older adults and 65 MCI patients underwent structural MRI and completed cognitive testing, including the Immediate and Delayed Memory indices from the RBANS. Results generally replicated previous relationships between key medial temporal lobe regions and memory test performance, though comparison of NQ regions revealed statistically different values that were biased toward one version or the other depending on the region. NQ2 hippocampal z-scores explained additional variance in memory performance relative to %ICV values. Findings indicate that NQ1/2 medial temporal lobe volumes, especially age- and sex-based z-scores, hold clinical value, though caution is warranted when directly comparing volumes across NQ versions. PMID:29060939

The impact of sex and language dominance on material-specific memory before and after left temporal lobe surgery.

PubMed

Helmstaedter, C; Brosch, T; Kurthen, M; Elger, C E

2004-07-01

Recent findings raised evidence that in early-onset left temporal lobe epilepsy, women show greater functional plasticity for verbal memory than men. In particular, women with lesion- or epilepsy-driven atypical language dominance show an advantage over men. The question asked in this study was whether there is evidence of sex- and language dominance-dependent late, i.e. adult age, plasticity for verbal memory when epilepsy surgery is performed in these patients. Pre- and 1-year postoperative memory performance was evaluated in 169 patients (94 males and 75 females) who underwent left temporal lobe surgery and who had WADA testing of hemispheric language dominance prior to surgery. Verbal memory and figural memory were assessed by list-learning paradigms. According to the Bonn intracarotid amobarbital test (IAT) protocol, patients were categorized into left dominant or atypically dominant (right, incomplete left or right, and bilateral dominant) groups. Results were controlled for the hypothesized sex differences. Thirty-four percent of men and 47% of women displayed patterns of atypical language dominance. Atypical dominance was related to an early onset of epilepsy. Men showed a larger time window for development of atypical dominance but, differently from women, the pattern of atypical dominance was more strictly determined by the age at onset of epilepsy. Atypically dominant women showed better verbal memory than typically dominant women or men. After surgery, right dominant patients had better verbal memory outcome than patients with bilateral or left language dominance who showed significant memory loss. No effect of sex on verbal memory change was found. Figural memory deteriorated in men and improved in women, when they were not left dominant. Seizure outcome had no effect on performance changes. It was concluded that better preserved verbal memory in atypically dominant women before surgery indicates greater benefit from atypical dominance in women than men with regard to the initial damage associated with left hemisphere epilepsy. Later in life, when epilepsy surgery causes additional damage, no such sex difference is observed, indicating that the women's advantage over men is fixed to an early time window in life. Postoperative changes in figural memory suggest dynamics in crowding and suppression patterns. Whether this reflects late plasticity and compensation needs further demonstration. For clinical practice, it is important to note that incomplete right hemisphere and bilateral language dominance do not protect against verbal memory loss after left-sided temporal lobe surgery. Copyright 2004 Guarantors of Brain

Abnormal functional connectivity of hippocampus during episodic memory retrieval processing network in amnestic mild cognitive impairment.

PubMed

Bai, Feng; Zhang, Zhijun; Watson, David R; Yu, Hui; Shi, Yongmei; Yuan, Yonggui; Zang, Yufeng; Zhu, Chaozhe; Qian, Yun

2009-06-01

Functional connectivity magnetic resonance imaging technique has revealed the importance of distributed network structures in higher cognitive processes in the human brain. The hippocampus has a key role in a distributed network supporting memory encoding and retrieval. Hippocampal dysfunction is a recurrent finding in memory disorders of aging such as amnestic mild cognitive impairment (aMCI) in which learning- and memory-related cognitive abilities are the predominant impairment. The functional connectivity method provides a novel approach in our attempts to better understand the changes occurring in this structure in aMCI patients. Functional connectivity analysis was used to examine episodic memory retrieval networks in vivo in twenty 28 aMCI patients and 23 well-matched control subjects, specifically between the hippocampal structures and other brain regions. Compared with control subjects, aMCI patients showed significantly lower hippocampus functional connectivity in a network involving prefrontal lobe, temporal lobe, parietal lobe, and cerebellum, and higher functional connectivity to more diffuse areas of the brain than normal aging control subjects. In addition, those regions associated with increased functional connectivity with the hippocampus demonstrated a significantly negative correlation to episodic memory performance. aMCI patients displayed altered patterns of functional connectivity during memory retrieval. The degree of this disturbance appears to be related to level of impairment of processes involved in memory function. Because aMCI is a putative prodromal syndrome to Alzheimer's disease (AD), these early changes in functional connectivity involving the hippocampus may yield important new data to predict whether a patient will eventually develop AD.

[Neural Mechanisms Underlying the Processing of Temporal Information in Episodic Memory and Its Disturbance].

PubMed

Iwata, Saeko; Tsukiura, Takashi

2017-11-01

Episodic memory is defined as memory for personally experienced events, and includes memory content and contextual information of time and space. Previous neuroimaging and neuropsychological studies have demonstrated three possible roles of the temporal context in episodic memory. First, temporal information contributes to the arrangement of temporal order for sequential events in episodic memory, and this process is involved in the lateral prefrontal cortex. The second possible role of temporal information in episodic memory is the segregation between memories of multiple events, which are segregated by cues of different time information. The role of segregation is associated with the orbitofrontal regions including the orbitofrontal cortex and basal forebrain region. Third, temporal information in episodic memory plays an important role in the integration of multiple components into a coherent episodic memory, in which episodic components in the different modalities are combined by temporal information as an index. The role of integration is mediated by the medial temporal lobe including the hippocampus and parahippocampal gyrus. Thus, temporal information in episodic memory could be represented in multiple stages, which are involved in a network of the lateral prefrontal, orbitofrontal, and medial temporal lobe regions.

The functional neuroanatomy of verbal memory in Alzheimer's disease: [18F]-Fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) correlates of recency and recognition memory.

PubMed

Staffaroni, Adam M; Melrose, Rebecca J; Leskin, Lorraine P; Riskin-Jones, Hannah; Harwood, Dylan; Mandelkern, Mark; Sultzer, David L

2017-09-01

The objective of this study was to distinguish the functional neuroanatomy of verbal learning and recognition in Alzheimer's disease (AD) using the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) Word Learning task. In 81 Veterans diagnosed with dementia due to AD, we conducted a cluster-based correlation analysis to assess the relationships between recency and recognition memory scores from the CERAD Word Learning Task and cortical metabolic activity measured using [ 18 F]-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET). AD patients (Mini-Mental State Examination, MMSE mean = 20.2) performed significantly better on the recall of recency items during learning trials than of primacy and middle items. Recency memory was associated with cerebral metabolism in the left middle and inferior temporal gyri and left fusiform gyrus (p < .05 at the corrected cluster level). In contrast, recognition memory was correlated with metabolic activity in two clusters: (a) a large cluster that included the left hippocampus, parahippocampal gyrus, entorhinal cortex, anterior temporal lobe, and inferior and middle temporal gyri; (b) the bilateral orbitofrontal cortices (OFC). The present study further informs our understanding of the disparate functional neuroanatomy of recency memory and recognition memory in AD. We anticipated that the recency effect would be relatively preserved and associated with temporoparietal brain regions implicated in short-term verbal memory, while recognition memory would be associated with the medial temporal lobe and possibly the OFC. Consistent with our a priori hypotheses, list learning in our AD sample was characterized by a reduced primacy effect and a relatively spared recency effect; however, recency memory was associated with cerebral metabolism in inferior and lateral temporal regions associated with the semantic memory network, rather than regions associated with short-term verbal memory. The correlates of recognition memory included the medial temporal lobe and OFC, replicating prior studies.

A computational model of prefrontal control in free recall: strategic memory use in the California Verbal Learning Task.

PubMed

Becker, Suzanna; Lim, Jean

2003-08-15

Several decades of research into the function of the frontal lobes in brain-damaged patients, and more recently in intact individuals using function brain imaging, has delineated the complex executive functions of the frontal cortex. And yet, the mechanisms by which the brain achieves these functions remain poorly understood. Here, we present a computational model of the role of the prefrontal cortex (PFC) in controlled memory use that may help to shed light on the mechanisms underlying one aspect of frontal control: the development and deployment of recall strategies. The model accounts for interactions between the PFC and medial temporal lobe in strategic memory use. The PFC self-organizes its own mnemonic codes using internally derived performance measures. These mnemonic codes serve as retrieval cues by biasing retrieval in the medial temporal lobe memory system. We present data from three simulation experiments that demonstrate strategic encoding and retrieval in the free recall of categorized lists of words. Experiment 1 compares the performance of the model with two control networks to evaluate the contribution of various components of the model. Experiment 2 compares the performance of normal and frontally lesioned models to data from several studies using frontally intact and frontally lesioned individuals, as well as normal, healthy individuals under conditions of divided attention. Experiment 3 compares the model's performance on the recall of blocked and unblocked categorized lists of words to data from Stuss et al. (1994) for individuals with control and frontal lobe lesions. Overall, our model captures a number of aspects of human performance on free recall tasks: an increase in total words recalled and in semantic clustering scores across trials, superiority on blocked lists of related items compared to unblocked lists of related items, and similar patterns of performance across trials in the normal and frontally lesioned models, with poorer overall performance of the lesioned models on all measures. The model also has a number of shortcomings, in light of which we suggest extensions to the model that would enable more sophisticated forms of strategic control.

Course of Relational and Non-Relational Recognition Memory across the Adult Lifespan

ERIC Educational Resources Information Center

Soei, Eleonore; Daum, Irene

2008-01-01

Human recognition memory shows a decline during normal ageing, which is thought to be related to age-associated dysfunctions of mediotemporal lobe structures. Whether the hippocampus is critical for human general relational memory or for spatial relational memory only is still disputed. The human perirhinal cortex is thought to be critically…

Semantic Memory Recognition Is Supported by Intrinsic Recollection-Like Processes: "The Butcher on the Bus" Revisited

ERIC Educational Resources Information Center

Waidergoren, Shani; Segalowicz, Judith; Gilboa, Asaf

2012-01-01

Dual-process models suggest that recognition memory is independently supported by recollection and familiarity. Current theories attribute recollection solely to hippocampally mediated episodic memory (EM), and familiarity to both episodic and semantic memory (SM) supported by medial temporal lobe cortex (MTLC) and prefrontal cortex. We tested…

Implicit and Explicit Memory in Autism: Is Autism an Amnesic Disorder?

ERIC Educational Resources Information Center

Renner, Peggy; Klinger, Laura Grofer; Klinger, Mark R.

2000-01-01

This study examined whether children with high-functioning autism have a dissociation between explicit and implicit memory abilities characteristic of medial temporal lobe amnesic disorder. Children (N=14 and ages 6-14) with autism showed intact implicit and explicit memory abilities but did not show typical memory patterns, suggesting they used…

Sensitivity and specificity of memory and naming tests for identifying left temporal-lobe epilepsy.

PubMed

Umfleet, Laura Glass; Janecek, Julie K; Quasney, Erin; Sabsevitz, David S; Ryan, Joseph J; Binder, Jeffrey R; Swanson, Sara J

2015-01-01

The sensitivity and specificity of the Selective Reminding Test (SRT) Delayed Recall, Wechsler Memory Scale (WMS) Logical Memory, the Boston Naming Test (BNT), and two nonverbal memory measures for detecting lateralized dysfunction in association with side of seizure focus was examined in a sample of 143 patients with left or right temporal-lobe epilepsy (TLE). Scores on the SRT and BNT were statistically significantly lower in the left TLE group compared with the right TLE group, whereas no group differences emerged on the Logical Memory subtest. No significant group differences were found with nonverbal memory measures. When the SRT and BNT were both entered as predictors in a logistic regression, the BNT, although significant, added minimal value to the model beyond the variance accounted for by the SRT Delayed Recall. Both variables emerged as significant predictors of side of seizure focus when entered into separate regressions. Sensitivity and specificity of the SRT and BNT ranged from 56% to 65%. The WMS Logical Memory and nonverbal memory measures were not significant predictors of the side of seizure focus.

Remembering first impressions: effects of intentionality and diagnosticity on subsequent memory.

PubMed

Gilron, Roee; Gutchess, Angela H

2012-03-01

People rely on first impressions every day as an important tool to interpret social behavior. While research is beginning to reveal the neural underpinnings of first impressions, particularly through understanding the role of dorsal medial prefrontal cortex (dmPFC), little is known about the way in which first impressions are encoded into memory. This is surprising because first impressions are relevant from a social perspective for future interactions, requiring that they be transferred to memory. The present study used a subsequent-memory paradigm to test the conditions under which the dmPFC is implicated in the encoding of first impressions. We found that intentionally forming impressions engages the dmPFC more than does incidentally forming impressions, and that this engagement supports the encoding of remembered impressions. In addition, we found that diagnostic information, which more readily lends itself to forming trait impressions, engages the dmPFC more than does neutral information. These results indicate that the neural system subserving memory for impressions is sensitive to consciously formed impressions. The results also suggest a distinction between a social memory system and other explicit memory systems governed by the medial temporal lobes.

Remembering first impressions: Effects of intentionality and diagnosticity on subsequent memory

PubMed Central

Gilron, Roee; Gutchess, Angela H.

2012-01-01

People rely on first impressions every day as an important tool to interpret social behavior. While research is beginning to reveal the neural underpinnings of first impressions, particularly through understanding the role of dorsal medial prefrontal cortex (dmPFC), little is known about the way in which first impressions are encoded into memory. This is surprising because first impressions are relevant from a social perspective for future interactions, requiring that they be transferred to memory. The present study used a subsequent memory paradigm to test the conditions under which the dmPFC is implicated in the encoding of first impressions. We found that intentionally forming impressions engages the dmPFC more than incidentally forming impressions and that this engagement supports the encoding of remembered impressions. In addition, we found that diagnostic information, which more readily lends itself to forming trait impressions, engages the dmPFC more than neutral information. These results indicate that the neural system subserving memory for impressions is sensitive to consciously formed impressions. The results also suggest a distinction between a social memory system and other explicit memory systems governed by the medial temporal lobes. PMID:22139633

Multi-voxel patterns of visual category representation during episodic encoding are predictive of subsequent memory

PubMed Central

Kuhl, Brice A.; Rissman, Jesse; Wagner, Anthony D.

2012-01-01

Successful encoding of episodic memories is thought to depend on contributions from prefrontal and temporal lobe structures. Neural processes that contribute to successful encoding have been extensively explored through univariate analyses of neuroimaging data that compare mean activity levels elicited during the encoding of events that are subsequently remembered vs. those subsequently forgotten. Here, we applied pattern classification to fMRI data to assess the degree to which distributed patterns of activity within prefrontal and temporal lobe structures elicited during the encoding of word-image pairs were diagnostic of the visual category (Face or Scene) of the encoded image. We then assessed whether representation of category information was predictive of subsequent memory. Classification analyses indicated that temporal lobe structures contained information robustly diagnostic of visual category. Information in prefrontal cortex was less diagnostic of visual category, but was nonetheless associated with highly reliable classifier-based evidence for category representation. Critically, trials associated with greater classifier-based estimates of category representation in temporal and prefrontal regions were associated with a higher probability of subsequent remembering. Finally, consideration of trial-by-trial variance in classifier-based measures of category representation revealed positive correlations between prefrontal and temporal lobe representations, with the strength of these correlations varying as a function of the category of image being encoded. Together, these results indicate that multi-voxel representations of encoded information can provide unique insights into how visual experiences are transformed into episodic memories. PMID:21925190

Déjà vu: possible parahippocampal mechanisms.

PubMed

Spatt, Josef

2002-01-01

Déjà vu experiences are common in normal subjects. In addition, they are established symptoms of temporal lobe seizures. The author argues that the phenomenon is the result of faulty and isolated activity of a recognition memory system that consists of the parahippocampal gyrus and its neocortical connections. This memory system is responsible for judgments of familiarity. The result is that a momentary perceived scene is given the characteristics of familiarity that normally accompany a conscious recollection. The normal functioning of other brain structures involved in memory retrieval--the prefrontal cortex and the hippocampus proper--leads to the perplexing phenomenological quality of déjà vu. The hypothesis accounts for many characteristics of déjà vu in healthy subjects and is well fitting with experimental findings in patients with epilepsy.

In search of a recognition memory engram

PubMed Central

Brown, M.W.; Banks, P.J.

2015-01-01

A large body of data from human and animal studies using psychological, recording, imaging, and lesion techniques indicates that recognition memory involves at least two separable processes: familiarity discrimination and recollection. Familiarity discrimination for individual visual stimuli seems to be effected by a system centred on the perirhinal cortex of the temporal lobe. The fundamental change that encodes prior occurrence within the perirhinal cortex is a reduction in the responses of neurones when a stimulus is repeated. Neuronal network modelling indicates that a system based on such a change in responsiveness is potentially highly efficient in information theoretic terms. A review is given of findings indicating that perirhinal cortex acts as a storage site for recognition memory of objects and that such storage depends upon processes producing synaptic weakening. PMID:25280908

Patients' perceptions of memory functioning before and after surgical intervention to treat medically refractory epilepsy.

PubMed

Lineweaver, Tara T; Naugle, Richard I; Cafaro, Alyce M; Bingaman, William; Lüders, Hans O

2004-12-01

One risk associated with epilepsy surgery is memory loss, but perhaps more important is how patients perceive changes in their memories. This longitudinal study evaluated changes in memory self-reports and investigated how self-reports relate to changes on objective memory measures in temporal or extratemporal epilepsy patients who underwent surgery. Objective memory (Wechsler Memory Scale-Revised) and subjective memory self-reports (Memory Assessment Clinics Self-Rating Scale) were individually assessed for 136 patients approximately 6 months before and 6 months after surgery. A measure of depressive affect (Beck Depression Inventory-2nd Edition) was used to control variance attributable to emotional distress. Despite a lack of significant correlational relationships between objective and subjective memory for the entire sample, significant correlations between objective memory scores and self-reports did emerge for a subset of patients who evidenced memory decline. Differences also were found in the subjective memory ratings of temporal lobe versus extratemporal patients. Temporal lobe patients rated their memories more negatively than did extratemporal patients and were more likely to report significant improvements in their memory after surgery. In general, patients were not accurate when rating their memories compared to other adults. However, patients with significant declines in their memories were sensitive to actual changes in their memories over time relative to their own personal baselines.

Rey's 15-Item Visual Memory Test for the Detection of Malingering: Normative Observations on Patients with Neurological Disorders.

ERIC Educational Resources Information Center

Lee, Gregory P.; And Others

1992-01-01

To gather normative observations on a visual memory test developed by A. Rey (1964), it was administered to 100 temporal-lobe epilepsy patients with memory deficits and 56 outpatients with neurological disorders. Results suggest a cutoff score of 7 on the memory test may alert the clinician to possible factitious memory complaints. (SLD)

Nonvisual spatial navigation fMRI lateralizes mesial temporal lobe epilepsy in a patient with congenital blindness.

PubMed

Toller, Gianina; Adhimoolam, Babu; Grunwald, Thomas; Huppertz, Hans-Jürgen; König, Kristina; Jokeit, Hennric

2015-01-01

Nonvisual spatial navigation functional magnetic resonance imaging (fMRI) may help clinicians determine memory lateralization in blind individuals with refractory mesial temporal lobe epilepsy (MTLE). We report on an exceptional case of a congenitally blind woman with late-onset left MTLE undergoing presurgical memory fMRI. To activate mesial temporal structures despite the lack of visual memory, the patient was requested to recall familiar routes using nonvisual multisensory and verbal cues. Our findings demonstrate the diagnostic value of a nonvisual fMRI task to lateralize MTLE despite congenital blindness and may therefore contribute to the risk assessment for postsurgical amnesia in rare cases with refractory MTLE and accompanying congenital blindness.

Functional neuroanatomy of sustained memory encoding performance in healthy aging and in Alzheimer's disease.

PubMed

Weis, Susanne; Leube, Dirk; Erb, Michael; Heun, Reinhard; Grodd, Wolfgang; Kircher, Tilo

2011-07-01

The aim of our study was to examine brain networks involved with sustaining memory encoding performance in healthy aging and in Alzheimer's disease (AD). Since different brain regions are affected by degradation in these two conditions, it might be conceivable that different compensation mechanisms occur to keep up memory performance in aging and in AD. Using an event-related functional magnetic resonance imaging (FMRI) design and a correlation analysis, 8 patients suffering from AD and 29 elderly control subjects were scanned while they studied a list of words for a subsequent memory test. Individual performance was assessed on the basis of a subsequent recognition test, and brain regions were identified where functional activations during study correlated with memory performance. In both groups, successful memory encoding performance was significantly correlated with the activation of the right frontal cortex. Furthermore, in healthy controls, there was a significant correlation of memory performance and the activation of the left medial and lateral temporal lobe. In contrast, in AD patients, increasing memory performance goes along with increasing activation of the hippocampus and a bilateral brain network including the frontal and temporal cortices. Our data show that in healthy aging and in AD, common and distinct compensatory mechanisms are employed to keep up a certain level of memory performance. Both in healthy aging and in patients with AD, an increased level of monitoring and control processes mediated by the (right) frontal lobe seems to be necessary to maintain a certain level of memory performance. In addition, memory performance in healthy older subjects seems to rely on an increased effort in encoding item-specific semantic and contextual information in lateral areas of the (left) temporal lobe. In AD patients, on the other hand, the maintenance of memory performance is related to an increase of activation of the (left) hippocampus in conjunction with a bilateral network of cortical areas that might be involved with phonological and visual rehearsal of the incoming information.

Memory deficits in amyotrophic lateral sclerosis are not exclusively caused by executive dysfunction: a comparative neuropsychological study of amnestic mild cognitive impairment.

PubMed

Machts, Judith; Bittner, Verena; Kasper, Elisabeth; Schuster, Christina; Prudlo, Johannes; Abdulla, Susanne; Kollewe, Katja; Petri, Susanne; Dengler, Reinhard; Heinze, Hans-Jochen; Vielhaber, Stefan; Schoenfeld, Mircea A; Bittner, Daniel M

2014-06-30

Recent work suggests that ALS and frontotemporal dementia can occur together and share at least in part the same underlying pathophysiology. However, it is unclear at present whether memory deficits in ALS stem from a temporal lobe dysfunction, or are rather driven by frontal executive dysfunction. In this study we sought to investigate the nature of memory deficits by analyzing the neuropsychological performance of 40 ALS patients in comparison to 39 amnestic mild cognitive impairment (aMCI) patients and 40 healthy controls (HC). The neuropsychological battery tested for impairment in executive functions, as well as memory and visuo-spatial skills, the results of which were compared across study groups. In addition, we calculated composite scores for memory (learning, recall, recognition) and executive functions (verbal fluency, cognitive flexibility, working memory). We hypothesized that the nature of memory impairment in ALS will be different from those exhibited by aMCI patients. Patient groups exhibited significant differences in their type of memory deficit, with the ALS group showing impairment only in recognition, whereas aMCI patients showed short and delayed recall performance deficits as well as reduced short-term capacity. Regression analysis revealed a significant impact of executive function on memory performance exclusively for the ALS group, accounting for one fifth of their memory performance. Interestingly, merging all sub scores into a single memory and an executive function score obscured these differences. The presented results indicate that the interpretation of neuropsychological scores needs to take the distinct cognitive profiles in ALS and aMCI into consideration. Importantly, the observed memory deficits in ALS were distinctly different from those observed in aMCI and can be explained only to some extent in the context of comorbid (coexisting) executive dysfunction. These findings highlight the qualitative differences in temporal lobe dysfunction between ALS and aMCI patients, and support temporal lobe dysfunction as a mechanism underlying the distinct cognitive impairments observed in ALS.

Intact implicit verbal relational memory in medial temporal lobe amnesia

PubMed Central

Verfaelllie, Mieke; LaRocque, Karen F.; Keane, Margaret M.

2012-01-01

To elucidate the role of the hippocampus in unaware relational memory, the present study examined the performance of amnesic patients with medial temporal lobe (MTL) lesions on a cued category-exemplar generation task. In contrast to a prior study in which amnesic patients showed impaired performance (Verfaellie et al., Cognitive, Affective, and Behavioral Neuroscience, 2006, 6, 91–101), the current study employed a task that required active processing of the context word at test. In this version of the task, amnesic patients, like control participants, showed enhanced category exemplar priming when the context word associated with the target at study was reinstated at test. The finding of intact implicit memory for novel associations following hippocampal lesions in a task that requires flexible use of retrieval cues is inconsistent with a relational memory view that suggests that the hippocampus is critical for all forms of relational memory, regardless of awareness. Instead, it suggests that unaware memory for within-domain associations does not require MTL mediation. PMID:22609574

Tau and β-Amyloid Are Associated with Medial Temporal Lobe Structure, Function, and Memory Encoding in Normal Aging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marks, Shawn M.; Lockhart, Samuel N.; Baker, Suzanne L.

Normal aging is associated with a decline in episodic memory and also with aggregation of the β-amyloid (Aβ) and tau proteins and atrophy of medial temporal lobe (MTL) structures crucial to memory formation. Although some evidence suggests that Aβ is associated with aberrant neural activity, the relationships among these two aggregated proteins, neural function, and brain structure are poorly understood. Using in vivo human Aβ and tau imaging, we demonstrate that increased Aβ and tau are both associated with aberrant fMRI activity in the MTL during memory encoding in cognitively normal older adults. This pathological neural activity was in turnmore » associated with worse memory performance and atrophy within the MTL. A mediation analysis revealed that the relationship with regional atrophy was explained by MTL tau. These findings broaden the concept of cognitive aging to include evidence of Alzheimer’s disease-related protein aggregation as an underlying mechanism of age-related memory impairment.« less

Social cognition and the anterior temporal lobes: a review and theoretical framework

PubMed Central

McCoy, David; Klobusicky, Elizabeth; Ross, Lars A.

2013-01-01

Memory for people and their relationships, along with memory for social language and social behaviors, constitutes a specific type of semantic memory termed social knowledge. This review focuses on how and where social knowledge is represented in the brain. We propose that portions of the anterior temporal lobe (ATL) play a critical role in representing and retrieving social knowledge. This includes memory about people, their names and biographies and more abstract forms of social memory such as memory for traits and social concepts. This hypothesis is based on the convergence of several lines of research including anatomical findings, lesion evidence from both humans and non-human primates and neuroimaging evidence. Moreover, the ATL is closely interconnected with cortical nuclei of the amygdala and orbitofrontal cortex via the uncinate fasciculus. We propose that this pattern of connectivity underlies the function of the ATL in encoding and storing emotionally tagged knowledge that is used to guide orbitofrontal-based decision processes. PMID:23051902

Kinesthetic working memory and action control within the dorsal stream.

PubMed

Fiehler, Katja; Burke, Michael; Engel, Annerose; Bien, Siegfried; Rösler, Frank

2008-02-01

There is wide agreement that the "dorsal (action) stream" processes visual information for movement control. However, movements depend not only on vision but also on tactile and kinesthetic information (=haptics). Using functional magnetic resonance imaging, the present study investigates to what extent networks within the dorsal stream are also utilized for kinesthetic action control and whether they are also involved in kinesthetic working memory. Fourteen blindfolded participants performed a delayed-recognition task in which right-handed movements had to be encoded, maintained, and later recognized without any visual feedback. Encoding of hand movements activated somatosensory areas, superior parietal lobe (dorsodorsal stream), anterior intraparietal sulcus (aIPS) and adjoining areas (ventrodorsal stream), premotor cortex, and occipitotemporal cortex (ventral stream). Short-term maintenance of kinesthetic information elicited load-dependent activity in the aIPS and adjacent anterior portion of the superior parietal lobe (ventrodorsal stream) of the left hemisphere. We propose that the action representation system of the dorsodorsal and ventrodorsal stream is utilized not only for visual but also for kinesthetic action control. Moreover, the present findings demonstrate that networks within the ventrodorsal stream, in particular the left aIPS and closely adjacent areas, are also engaged in working memory maintenance of kinesthetic information.

Low-Complexity Discriminative Feature Selection From EEG Before and After Short-Term Memory Task.

PubMed

Behzadfar, Neda; Firoozabadi, S Mohammad P; Badie, Kambiz

2016-10-01

A reliable and unobtrusive quantification of changes in cortical activity during short-term memory task can be used to evaluate the efficacy of interfaces and to provide real-time user-state information. In this article, we investigate changes in electroencephalogram signals in short-term memory with respect to the baseline activity. The electroencephalogram signals have been analyzed using 9 linear and nonlinear/dynamic measures. We applied statistical Wilcoxon examination and Davis-Bouldian criterion to select optimal discriminative features. The results show that among the features, the permutation entropy significantly increased in frontal lobe and the occipital second lower alpha band activity decreased during memory task. These 2 features reflect the same mental task; however, their correlation with memory task varies in different intervals. In conclusion, it is suggested that the combination of the 2 features would improve the performance of memory based neurofeedback systems. © EEG and Clinical Neuroscience Society (ECNS) 2016.

Mechanisms for widespread hippocampal involvement in cognition

PubMed Central

Shohamy, Daphna; Turk-Browne, Nicholas B.

2014-01-01

The quintessential memory system in the human brain — the hippocampus and surrounding medial temporal lobe (MTL) — is often treated as a module for the formation of conscious, or declarative memories. However, growing evidence suggests that the hippocampus plays a broader role in memory and cognition and that theories organizing memory into strictly dedicated systems may need to be updated. We first consider the historical evidence for the specialized role of the hippocampus in declarative memory. Then, we describe the serendipitous encounter that motivated this special section, based on parallel research from our labs that suggested a more pervasive contribution of the hippocampus to cognition beyond declarative memory. Finally, we develop a theoretical framework that describes two general mechanisms for how the hippocampus interacts with other brain systems and cognitive processes: the Memory Modulation Hypothesis, in which mnemonic representations in the hippocampus modulate the operation of other systems, and the Adaptive Function Hypothesis, in which specialized computations in the hippocampus are recruited as a component of both mnemonic and non-mnemonic functions. This framework is consistent with an emerging view that the most fertile ground for discovery in cognitive psychology and neuroscience lies at the interface between parts of the mind and brain that have traditionally been studied in isolation. PMID:24246058

Hippocampus at 25.

PubMed

Eichenbaum, Howard; Amaral, David G; Buffalo, Elizabeth A; Buzsáki, György; Cohen, Neal; Davachi, Lila; Frank, Loren; Heckers, Stephan; Morris, Richard G M; Moser, Edvard I; Nadel, Lynn; O'Keefe, John; Preston, Alison; Ranganath, Charan; Silva, Alcino; Witter, Menno

2016-10-01

The journal Hippocampus has passed the milestone of 25 years of publications on the topic of a highly studied brain structure, and its closely associated brain areas. In a recent celebration of this event, a Boston memory group invited 16 speakers to address the question of progress in understanding the hippocampus that has been achieved. Here we present a summary of these talks organized as progress on four main themes: (1) Understanding the hippocampus in terms of its interactions with multiple cortical areas within the medial temporal lobe memory system, (2) understanding the relationship between memory and spatial information processing functions of the hippocampal region, (3) understanding the role of temporal organization in spatial and memory processing by the hippocampus, and (4) understanding how the hippocampus integrates related events into networks of memories. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

The role of involuntary aware memory in the implicit stem and fragment completion tasks: a selective review.

PubMed

Kinoshita, S

2001-03-01

In this article I argue that an awareness of the study episode that arises involuntarily during an implicit stem/fragment completion test can under some conditions lead to enhanced repetition priming effects, even though subjects are not engaged in intentional retrieval. I review findings that are consistent with this possibility, which include the effects of depth of processing, and of typography match and new association priming following deep encoding. A theoretical account of involuntary aware memory couched within Moscovitch's (1995b) memory systems framework which suggests that the medial-temporal lobe/hippocampal (MTL/H) complex functions as a memory module is outlined. A putative mechanism is proposed in which involuntary aware memory of a studied item enhances the size of repetition priming effects by guiding its selection in preference to the competitors.

The Relevance of the Nature of Learned Associations for the Differentiation of Human Memory Systems

ERIC Educational Resources Information Center

Rose, Michael; Haider, Hilde; Weiller, Cornelius; Buchel, Christian

2004-01-01

In a previous functional magnetic resonance imaging (fMRI) study we demonstrated an involvement of the medial temporal lobe (MTL) during an implicit learning task. We concluded that the MTL was engaged because of the complex contingencies that were implicitly learned. In addition, the basal ganglia demonstrated effects of a paralleled…

Memory for relations in the short term and the long term after medial temporal lobe damage.

PubMed

Squire, Larry R

2017-05-01

A central idea about the organization of declarative memory and the function of the hippocampus is that the hippocampus provides for the coding of relationships between items. A question arises whether this idea refers to the process of forming long-term memory or whether, as some studies have suggested, memory for relations might depend on the hippocampus even at short retention intervals and even when the task falls within the province of short-term (working) memory. The latter formulation appears to place the operation of relational memory into conflict with the idea that working memory is independent of medial temporal lobe (MTL) structures. In this report, the concepts of relational memory and working memory are discussed in the light of a simple demonstration experiment. Patients with MTL lesions successfully learned and recalled two word pairs when tested directly after learning but failed altogether when tested after a delay. The results do not contradict the idea that the hippocampus has a fundamental role in relational memory. However, there is a need for further elaboration and specification of the idea in order to explain why patients with MTL lesions can establish relational memory in the short term but not in long-term memory. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

True Memory, False Memory, and Subjective Recollection Deficits after Focal Parietal Lobe Lesions

PubMed Central

Drowos, David B.; Berryhill, Marian; André, Jessica M.; Olson, Ingrid R.

2010-01-01

Objective There is mounting evidence that the posterior parietal cortex (PPC) plays an important role in episodic memory. We previously found that patients with PPC damage exhibit retrieval-related episodic memory deficits. Our objective was to assess whether parietal lobe damage affects episodic memory on a different task: the Deese-Roediger-McDermott (DRM) false-memory paradigm. Method Two patients with bilateral PPC damage and matched controls were tested. In Experiment 1, the task was to remember words; in Experiment 2 the task was to remember pictures of common objects. Prior studies have shown that normal participants have high levels of false memory to words, low levels to pictures. Results The patients exhibited significantly lower levels of false memory to words. The patients' false memories were accompanied by reduced levels of recollection, as tested by a Remember/Know procedure. It is unlikely that a failure of gist processing accounts for these results, as patients accurately remembered thematic elements of short vignettes, but failed to remember details. These results support the view that portions of the PPC play a critical role in objective and subjective aspects of recollection. PMID:20604621

Autobiographical memory and patterns of brain atrophy in frontotemporal lobar degeneration.

PubMed

McKinnon, Margaret C; Nica, Elena I; Sengdy, Pheth; Kovacevic, Natasa; Moscovitch, Morris; Freedman, Morris; Miller, Bruce L; Black, Sandra E; Levine, Brian

2008-10-01

Autobiographical memory paradigms have been increasingly used to study the behavioral and neuroanatomical correlates of human remote memory. Although there are numerous functional neuroimaging studies on this topic, relatively few studies of patient samples exist, with heterogeneity of results owing to methodological variability. In this study, fronto-temporal lobar degeneration (FTLD), a form of dementia affecting regions crucial to autobiographical memory, was used as a model of autobiographical memory loss. We emphasized the separation of episodic (recollection of specific event, perceptual, and mental state information) from semantic (factual information unspecific in time and place) autobiographical memory, derived from a reliable method for scoring transcribed autobiographical protocols, the Autobiographical Interview [Levine, B., Svoboda, E., Hay, J., Winocur, G., & Moscovitch, M. Aging and autobiographical memory: Dissociating episodic from semantic retrieval. Psychology and Aging, 17, 677-689, 2002]. Patients with the fronto-temporal dementia (FTD) and mixed fronto-temporal and semantic dementia (FTD/SD) variants of FTLD were impaired at reconstructing episodically rich autobiographical memories across the lifespan, with FTD/SD patients generating an excess of generic semantic autobiographical information. Patients with progressive nonfluent aphasia were mildly impaired for episodic autobiographical memory, but this impairment was eliminated with the provision of structured cueing, likely reflecting relatively intact medial-temporal lobe function, whereas the same cueing failed to bolster the FTD and FTD/SD patients' performance relative to that of matched comparison subjects. The pattern of episodic, but not semantic, autobiographical impairment was enhanced with disease progression on 1- to 2-year follow-up testing in a subset of patients, supplementing the cross-sectional evidence for specificity of episodic autobiographical impairment with longitudinal data. This behavioral pattern covaried with volume loss in a distributed left-lateralized posterior network centered on the temporal lobe, consistent with evidence from other patient and functional neuroimaging studies of autobiographical memory. Frontal lobe volumes, however, did not significantly contribute to this network, suggesting that frontal contributions to autobiographical episodic memory may be more complex than previously appreciated.

Simulating memory outcome before right selective amygdalohippocampectomy.

PubMed

Patrikelis, Panayiotis; Lucci, Giuliana; Siatouni, Anna; Zalonis, Ioannis; Sakas, Damianos E; Gatzonis, Stylianos

2013-01-01

In this paper we present the case of a left-sided speech dominant patient with right medial temporal sclerosis (RMTS) and pharmacoresistant epilepsy who showed improved verbal memory during intracarotid amobarbital test (IAT) at his right hemisphere as compared with his own performance before the drug injection (baseline), as well as after right selective amygdalohippocampectomy. We suggest that the defective verbal memory shown by this patient is due to abnormal activity of his right hippocampus that interfered with the function of his left hippocampus. This hypothesis was demonstrated by the fact that disconnection of the two hippocampi, either by anesthetisation or by resection of the right hippocampus, disengaged the left hippocampus and, consequently improved its function. This paper main objective is twofold: first to contribute to the field of neuropsychology of epilepsy surgery by emphasising on postoperative memory outcomes in right medial temporal lobe epilepsy (RMTLE) patients, particularly those undergoing amygdalohippocampectomy, as the pattern of memory changes after resection of the right temporal lobe is less clear; second, by focusing on memory performance asymmetries during IAT, and comparatively considering them with neuropsychological memory performance, because of their possible prognostic-simulating value.

Spatial working memory impairment in primary onset middle-age type 2 diabetes mellitus: An ethology and BOLD-fMRI study.

PubMed

Huang, Ran-Ran; Jia, Bao-Hui; Xie, Lei; Ma, Shu-Hua; Yin, Jing-Jing; Sun, Zong-Bo; Le, Hong-Bo; Xu, Wen-Can; Huang, Jin-Zhuang; Luo, Dong-Xue

2016-01-01

To explore mild cognitive dysfunction and/or spatial working memory impairment in patients with primary onset middle-age type 2 diabetes mellitus (T2DM] using ethology (behavior tests) and blood oxygen level-dependent functional magnetic resonance imaging (BOLD-fMRI). Eighteen primary onset T2DM patients and 18 matched subjects with normal blood glucose levels were all tested using the Montreal cognitive assessment scale test, the Wechsler Memory Scale Chinese-revised test, and scanned using BOLD-fMRI (1.5T, EPI sequence) while performing the n-back task to find the activation intensity of some cognition-related areas. The ethology results showed that T2DM patients had a mild cognitive impairment and memory dysfunction (P < 0.05). The fMRI scan identified a neural network consisting of bilateral dorsolateral prefrontal cortex (DLPFC), bilateral premotor area (PreMA), bilateral parietal lobe (PA), and anterior cingulate cortex (ACC) / supplementary motor area (SMA) that was activated during the n-back task, with right hemisphere dominance. However, only the right PA and ACC/SMA showed a load effect via quantitative analysis in the T2DM group; the activation intensity of most working memory-related brain areas for the T2DM group were lower than for the control group under three memory loads. Furthermore, we found that the activation intensity of some cognition-related areas, including the right insular lobe, left caudate nucleus, and bilateral hippocampus/parahippocampal gyrus were lower than the control group under the memory loads. Diabetes-related brain damage of primary onset middle-age T2DM patients with right DLPFC-posterior parietal lobe and parahippocampal gyrus default network causes impairment of spatial working memory and mild cognitive dysfunction. © 2015 Wiley Periodicals, Inc.

Advances in memory research: single-neuron recordings from the human medial temporal lobe aid our understanding of declarative memory.

PubMed

Viskontas, Indre V

2008-12-01

To gain a complete understanding of how the brain functions, both in illness and good health, data from multiple levels of analysis must be integrated. Technical advances have made direct recordings of neuronal activity deep inside the human brain tractable, providing a rare glimpse into cellular processes during long-term memory formation. Recent findings using intracranial recordings in the medial temporal lobe inform current neural network models of memory, and may lead to a more comprehensive understanding of the neural basis of memory-related processes. These recordings have shown that cells in the hippocampus appear to support declarative learning by distinguishing novel and familiar stimuli via changes in firing patterns. Some cells with highly selective and invariant responses have also been described, and these responses seem to represent abstract concepts such as identity, rather than superficial perceptual features of items. Importantly, however, both selective and globally responsive cells are capable of changing their preferred stimulus depending on the conscious demands of the task. Firing patterns of human medial temporal lobe neurons indicate that cells can be both plastic and stable in terms of the information that they code; although some cells show highly selective and reproducible excitatory responses when presented with a familiar object, other cells change their receptive fields in line with changes in experience and the cognitive environment.

Translational MRI Volumetry with NeuroQuant: Effects of Version and Normative Data on Relationships with Memory Performance in Healthy Older Adults and Patients with Mild Cognitive Impairment.

PubMed

Stelmokas, Julija; Yassay, Lance; Giordani, Bruno; Dodge, Hiroko H; Dinov, Ivo D; Bhaumik, Arijit; Sathian, K; Hampstead, Benjamin M

2017-01-01

NeuroQuant (NQ) is a fully-automated program that overcomes several existing limitations in the clinical translation of MRI-derived volumetry. The current study characterized differences between the original (NQ1) and an updated NQ version (NQ2) by 1) replicating previously identified relationships between neuropsychological test performance and medial temporal lobe volumes, 2) evaluating the level of agreement between NQ versions, and 3) determining if the addition of NQ2 age-/sex-based z-scores hold greater clinical utility for prediction of memory impairment than standard percent of intracranial volume (% ICV) values. Sixty-seven healthy older adults and 65 mild cognitive impairment patients underwent structural MRI and completed cognitive testing, including the Immediate and Delayed Memory indices from the Repeatable Battery for the Assessment of Neuropsychological Status. Results generally replicated previous relationships between key medial temporal lobe regions and memory test performance, though comparison of NQ regions revealed statistically different values that were biased toward one version or the other depending on the region. NQ2 hippocampal z-scores explained additional variance in memory performance relative to % ICV values. Findings indicate that NQ1/2 medial temporal lobe volumes, especially age- and sex-based z-scores, hold clinical value, though caution is warranted when directly comparing volumes across NQ versions.

The Doors and People Test: The Effect of Frontal Lobe Lesions on Recall and Recognition Memory Performance

PubMed Central

2016-01-01

Objective: Memory deficits in patients with frontal lobe lesions are most apparent on free recall tasks that require the selection, initiation, and implementation of retrieval strategies. The effect of frontal lesions on recognition memory performance is less clear with some studies reporting recognition memory impairments but others not. The majority of these studies do not directly compare recall and recognition within the same group of frontal patients, assessing only recall or recognition memory performance. Other studies that do compare recall and recognition in the same frontal group do not consider recall or recognition tests that are comparable for difficulty. Recognition memory impairments may not be reported because recognition memory tasks are less demanding. Method: This study aimed to investigate recall and recognition impairments in the same group of 47 frontal patients and 78 healthy controls. The Doors and People Test was administered as a neuropsychological test of memory as it assesses both verbal and visual recall and recognition using subtests that are matched for difficulty. Results: Significant verbal and visual recall and recognition impairments were found in the frontal patients. Conclusion: These results demonstrate that when frontal patients are assessed on recall and recognition memory tests of comparable difficulty, memory impairments are found on both types of episodic memory test. PMID:26752123

Gender differences in post-temporal lobectomy verbal memory and relationships between MRI hippocampal volumes and preoperative verbal memory.

PubMed

Trenerry, M R; Jack, C R; Cascino, G D; Sharbrough, F W; Ivnik, R J

1995-01-01

Thirty-three men and 42 women who underwent left, and 26 men and 24 women who underwent right temporal lobectomy (TL) were studied retrospectively to determine if there were sex differences in (1) verbal memory outcome, and (2) relationships between verbal memory and magnetic resonance imaging (MRI) hippocampal volumes. All patients were left hemisphere language dominant. The surgical specimen and MRI were consistent only with mesial temporal sclerosis (MTS). Verbal memory was evaluated by Logical Memory percent retention (LMPER) from the Wechsler Memory Scale-Revised (WMS-R). Women experienced a significant improvement while men experienced a significant decline in postoperative LMPER. The difference between right and left hippocampal volumes predicted verbal memory outcome in both men and women. Preoperative LMPER was positively correlated with both the left and right hippocampal volumes in left TL women only. No verbal memory sex differences or correlations between LMPER and MRI data were found in the right TL group. The data support the presence of human neurocognitive sexual dimorphism. Verbal memory abilities supported by the hippocampus are less lateralized in women with left temporal lobe epilepsy and mesial temporal sclerosis. Women appear to have greater verbal memory plasticity following early left mesial temporal lobe insult.

Accelerated long-term forgetting and autobiographical memory disorders in temporal lobe epilepsy: One entity or two?

PubMed

Lemesle, B; Planton, M; Pagès, B; Pariente, J

Temporal lobe epilepsy (TLE) is a type of epilepsy that often has a negative impact on patients' memory. Despite the importance of patients' complaints in this regard, the difficulties described by these patients are often not easy to demonstrate through a standard neuropsychological assessment. Accelerated long-term forgetting and autobiographical memory disorders are the two main memory impairments reported in the literature in patients with TLE. However, the methods used by different authors to evaluate long-term memory and autobiographical memory are heterogeneous. This heterogeneity can lead to differences in the observed results as well as how they are interpreted. Yet, despite the methodological differences, objectification of such memory deficits appears to be both specific and robust within this patient population. Analysis of the literature shows that accelerated long-term forgetting and autobiographical memory disorders share the same clinical characteristics. This leads to the assumption that they are, in fact, only one entity and that their evaluation may be done through a single procedure. Our proposal is to place this evaluation within the context of memory consolidation disorders. With such a perspective, evaluation of accelerated forgetting in autobiographical memory should consist of identifying a disorder in the formation and/or recovery of new memory traces. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

The Doors and People Test: The effect of frontal lobe lesions on recall and recognition memory performance.

PubMed

MacPherson, Sarah E; Turner, Martha S; Bozzali, Marco; Cipolotti, Lisa; Shallice, Tim

2016-03-01

Memory deficits in patients with frontal lobe lesions are most apparent on free recall tasks that require the selection, initiation, and implementation of retrieval strategies. The effect of frontal lesions on recognition memory performance is less clear with some studies reporting recognition memory impairments but others not. The majority of these studies do not directly compare recall and recognition within the same group of frontal patients, assessing only recall or recognition memory performance. Other studies that do compare recall and recognition in the same frontal group do not consider recall or recognition tests that are comparable for difficulty. Recognition memory impairments may not be reported because recognition memory tasks are less demanding. This study aimed to investigate recall and recognition impairments in the same group of 47 frontal patients and 78 healthy controls. The Doors and People Test was administered as a neuropsychological test of memory as it assesses both verbal and visual recall and recognition using subtests that are matched for difficulty. Significant verbal and visual recall and recognition impairments were found in the frontal patients. These results demonstrate that when frontal patients are assessed on recall and recognition memory tests of comparable difficulty, memory impairments are found on both types of episodic memory test. (c) 2016 APA, all rights reserved).

Differential Neural Activity during Search of Specific and General Autobiographical Memories elicited by Musical Cues

PubMed Central

Ford, Jaclyn Hennessey; Addis, Donna Rose; Giovanello, Kelly S.

2011-01-01

Previous neuroimaging studies that have examined autobiographical memory specificity have utilized retrieval cues associated with prior searches of the event, potentially changing the retrieval processes being investigated. In the current study, musical cues were used to naturally elicit memories from multiple levels of specificity (i.e., lifetime period, general event, and event-specific). Sixteen young adults participated in a neuroimaging study in which they retrieved autobiographical memories associated with musical cues. These musical cues led to the retrieval of highly emotional memories that had low levels of prior retrieval. Retrieval of all autobiographical memory levels was associated with activity in regions in the autobiographical memory network, specifically the ventromedial prefrontal cortex, posterior cingulate, and right medial temporal lobe. Owing to the use of music, memories from varying levels of specificity were retrieved, allowing for comparison of event memory and abstract personal knowledge, as well as comparison of specific and general event memory. Dorsolateral and dorsomedial prefrontal regions were engaged during event retrieval relative to personal knowledge retrieval, and retrieval of specific event memories was associated with increased activity in the bilateral medial temporal lobe and dorsomedial prefrontal cortex relative to retrieval of general event memories. These results suggest that the initial search processes for memories of different specificity levels preferentially engage different components of the autobiographical memory network. The potential underlying causes of these neural differences are discussed. PMID:21600227

Impaired extinction of fear and maintained amygdala-hippocampal theta synchrony in a mouse model of temporal lobe epilepsy.

PubMed

Lesting, Jörg; Geiger, Matthias; Narayanan, Rajeevan T; Pape, Hans-Christian; Seidenbecher, Thomas

2011-02-01

The relationship between epilepsy and fear has received much attention. However, seizure-modulated fear and physiologic or structural correlates have not been examined systematically, and the underlying basics of network levels remain unclear to date. Therefore, this project was set up to characterize the neurophysiologic basis of seizure-related fear and the contribution of the amygdala-hippocampus system. The experimental strategy was composed of the following steps: (1) use of the mouse pilocarpine model of temporal lobe epilepsy (TLE); (2) behavioral analyses of anxiety states in the elevated plus maze test, light-dark avoidance test, and Pavlovian fear conditioning; and (3) probing neurophysiologic activity patterns in amygdala-hippocampal circuits in freely behaving mice. Our results displayed no significant differences in basic anxiety levels comparing mice that developed spontaneous recurrent seizures (SRS) and controls. Furthermore, conditioned fear memory retrieval was not influenced in SRS mice. However, during fear memory extinction, SRS mice showed an extended freezing behavior and a maintained amygdala-hippocampal theta frequency synchronization compared to controls. These results indicate specific alterations in conditioned fear behavior and related neurophysiologic activities in the amygdala-hippocampal network contributing to impaired fear memory extinction in mice with TLE. Clinically, the nonextinguished fear memories may well contribute to the experience of fear in patients with TLE. Wiley Periodicals, Inc. © 2010 International League Against Epilepsy.

Differential influence of hippocampal subfields to memory formation: insights from patients with temporal lobe epilepsy.

PubMed

Coras, Roland; Pauli, Elisabeth; Li, Jinmei; Schwarz, Michael; Rössler, Karl; Buchfelder, Michael; Hamer, Hajo; Stefan, Hermann; Blumcke, Ingmar

2014-07-01

To clarify the anatomical organization of human memory remains a major challenge in clinical neuroscience. Experimental data suggest dentate gyrus granule cells play a major role in memory acquisition, i.e. pattern separation and rapid pattern completion, whereas hippocampal CA1 neurons are implicated in place memory and autobiographical memory retrieval. Patients with temporal lobe epilepsy present with a broad spectrum of memory impairment, which can be assessed during clinical examination. Although long seizure histories may contribute to a pathophysiological reorganization of functional connectivity, surgical resection of the epileptic hippocampus offers a unique possibility to anatomically study the differential contribution of hippocampal subfields to compromised learning and memory in humans. Herein, we tested the hypothesis of hippocampal subfield specialization in a series of 100 consecutive patients with temporal lobe epilepsy submitted to epilepsy surgery. Memory profiles were obtained from intracarotid amobarbital testing and non-invasive verbal memory assessment before surgery, and correlated with histopathologically quantified cell loss pattern in hippocampal subfields obtained from the same patients using the new international consensus classification for hippocampal sclerosis proposed by the International League against Epilepsy (HS ILAE). Interestingly, patients with CA1 predominant cell loss (HS ILAE Type 2; n = 13) did not show declarative memory impairment and were indistinguishable from patients without any hippocampal cell loss (n = 19). In contrast, 63 patients with neuronal loss affecting all hippocampal subfields including CA1, CA4 and dentate gyrus (HS ILAE Type 1), or predominant cell loss in CA4 and partially affecting also CA3 and dentate gyrus (HS ILAE Type 3, n = 5) showed significantly reduced declarative memory capacities (intracarotid amobarbital testing: P < 0.001; verbal memory: P < 0.05). Our results suggested an alternative model of how memory processing can be organized amongst hippocampal subfields, and that CA1 pyramidal cells are less critically involved in declarative human memory acquisition compared to dentate gyrus granule cells or CA4/CA3 pyramidal cells. © The Author (2014). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Alteration of Duration Mismatch Negativity Induced by Transcranial Magnetic Stimulation Over the Left Parietal Lobe.

PubMed

Oshima, Hirokazu; Shiga, Tetsuya; Niwa, Shin-Ichi; Enomoto, Hiroyuki; Ugawa, Yoshikazu; Yabe, Hirooki

2017-01-01

Mismatch negativity (MMN) is generated by a comparison between an incoming sound and the memory trace of preceding sounds stored in sensory memory without any attention to the sound. N100 (N1) is associated with the afferent response to sound onset and reflects early analysis of stimulus characteristics. MMN generators are present in the temporal and frontal lobe, and N1 generators are present in the temporal lobe. The parietal lobe is involved in MMN generation elicited by a change in duration. The anatomical network connecting these areas, lateralization, and the effect of the side of ear stimulation on MMN remain unknown. Thus, we studied the effects of low-frequency repetitive transcranial magnetic stimulation (rTMS) over the left parietal lobe on MMN and N1 in 10 healthy subjects. Low-frequency rTMS over the left parietal lobe decreased the amplitude of MMN following right ear sound stimulation, but the amplitude was unaffected with left ear sound stimulation. We observed no significant changes in the amplitude of N1 or the latency of MMN or N1. These results suggest that low-frequency rTMS over the left parietal lobe modulates the detection of early auditory changes in duration in healthy subjects. Stimulation that is contralateral to the side of the ear experiencing sound may affect the generation of duration MMN more than ipsilateral stimulation. © EEG and Clinical Neuroscience Society (ECNS) 2016.

In search of a recognition memory engram.

PubMed

Brown, M W; Banks, P J

2015-03-01

A large body of data from human and animal studies using psychological, recording, imaging, and lesion techniques indicates that recognition memory involves at least two separable processes: familiarity discrimination and recollection. Familiarity discrimination for individual visual stimuli seems to be effected by a system centred on the perirhinal cortex of the temporal lobe. The fundamental change that encodes prior occurrence within the perirhinal cortex is a reduction in the responses of neurones when a stimulus is repeated. Neuronal network modelling indicates that a system based on such a change in responsiveness is potentially highly efficient in information theoretic terms. A review is given of findings indicating that perirhinal cortex acts as a storage site for recognition memory of objects and that such storage depends upon processes producing synaptic weakening. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

At the Intersection of Attention and Memory: The Mechanistic Role of the Posterior Parietal Lobe in Working Memory

ERIC Educational Resources Information Center

Berryhill, Marian E.; Chein, Jason; Olson, Ingrid R.

2011-01-01

Portions of the posterior parietal cortex (PPC) play a role in working memory (WM) yet the precise mechanistic function of this region remains poorly understood. The "pure storage" hypothesis proposes that this region functions as a short-lived modality-specific memory store. Alternatively, the "internal attention" hypothesis proposes that the PPC…

Studying frequency processing of the brain to enhance long-term memory and develop a human brain protocol.

PubMed

Friedrich, Wernher; Du, Shengzhi; Balt, Karlien

2015-01-01

The temporal lobe in conjunction with the hippocampus is responsible for memory processing. The gamma wave is involved with this process. To develop a human brain protocol, a better understanding of the relationship between gamma and long-term memory is vital. A more comprehensive understanding of the human brain and specific analogue waves it uses will support the development of a human brain protocol. Fifty-eight participants aged between 6 and 60 years participated in long-term memory experiments. It is envisaged that the brain could be stimulated through binaural beats (sound frequency) at 40 Hz (gamma) to enhance long-term memory capacity. EEG recordings have been transformed to sound and then to an information standard, namely ASCII. Statistical analysis showed a proportional relationship between long-term memory and gamma activity. Results from EEG recordings indicate a pattern. The pattern was obtained through the de-codification of an EEG recording to sound and then to ASCII. Stimulation of gamma should enhance long term memory capacity. More research is required to unlock the human brains' protocol key. This key will enable the processing of information directly to and from human memory via gamma, the hippocampus and the temporal lobe.

Influence of anxiety on memory performance in temporal lobe epilepsy

PubMed Central

Brown, Franklin C.; Westerveld, Michael; Langfitt, John T.; Hamberger, Marla; Hamid, Hamada; Shinnar, Shlomo; Sperling, Michael R.; Devinsky, Orrin; Barr, William; Tracy, Joseph; Masur, David; Bazil, Carl W.; Spencer, Susan S.

2013-01-01

This study examined the degree to which anxiety contributed to inconsistent material-specific memory difficulties among 243 temporal lobe epilepsy patients from the Multisite Epilepsy Study. Visual memory performance on the Rey Complex Figure Test (RCFT) was lower for those with high versus low level of anxiety, but was not found to be related to side of TLE. Verbal memory on the California Verbal Learning Test (CVLT) was significantly lower for left than right TLE patients with low anxiety, but equally impaired for those with high anxiety. These results suggest that we can place more confidence in the ability of verbal memory tests like the CVLT to lateralize to left TLE for those with low anxiety, but that verbal memory will be less likely to produce lateralizing information for those with high anxiety. This suggests that more caution is needed when interpreting verbal memory tests for those with high anxiety. These results indicated that RCFT performance was significantly affected by anxiety and did not lateralize to either side, regardless of anxiety level. This study adds to the existing literature which suggests that drawing-based visual memory tests do not lateralize among TLE patients, regardless of anxiety level. PMID:24291525

Content-Specific Source Encoding in the Human Medial Temporal Lobe

ERIC Educational Resources Information Center

Awipi, T.; Davachi, L.

2008-01-01

Although the medial temporal lobe (MTL) is known to be essential for episodic encoding, the contributions of individual MTL subregions remain unclear. Data from recognition memory studies have provided evidence that the hippocampus supports relational encoding important for later episodic recollection, whereas the perirhinal cortex has been linked…

Differential Medial Temporal Lobe and Parietal Cortical Contributions to Real-world Autobiographical Episodic and Autobiographical Semantic Memory.

PubMed

Brown, Thackery I; Rissman, Jesse; Chow, Tiffany E; Uncapher, Melina R; Wagner, Anthony D

2018-04-18

Autobiographical remembering can depend on two forms of memory: episodic (event) memory and autobiographical semantic memory (remembering personally relevant semantic knowledge, independent of recalling a specific experience). There is debate about the degree to which the neural signals that support episodic recollection relate to or build upon autobiographical semantic remembering. Pooling data from two fMRI studies of memory for real-world personal events, we investigated whether medial temporal lobe (MTL) and parietal subregions contribute to autobiographical episodic and semantic remembering. During scanning, participants made memory judgments about photograph sequences depicting past events from their life or from others' lives, and indicated whether memory was based on episodic or semantic knowledge. Results revealed several distinct functional patterns: activity in most MTL subregions was selectively associated with autobiographical episodic memory; the hippocampal tail, superior parietal lobule, and intraparietal sulcus were similarly engaged when memory was based on retrieval of an autobiographical episode or autobiographical semantic knowledge; and angular gyrus demonstrated a graded pattern, with activity declining from autobiographical recollection to autobiographical semantic remembering to correct rejections of novel events. Collectively, our data offer insights into MTL and parietal cortex functional organization, and elucidate circuitry that supports different forms of real-world autobiographical memory.

Recognition and identification of famous faces in patients with unilateral temporal lobe epilepsy.

PubMed

Seidenberg, Michael; Griffith, Randall; Sabsevitz, David; Moran, Maria; Haltiner, Alan; Bell, Brian; Swanson, Sara; Hammeke, Thomas; Hermann, Bruce

2002-01-01

We examined the performance of 21 patients with unilateral temporal lobe epilepsy (TLE) and hippocampal damage (10 lefts, and 11 rights) and 10 age-matched controls on the recognition and identification (name and occupation) of well-known faces. Famous face stimuli were selected from four time periods; 1970s, 1980s, 1990-1994, and 1995-1996. Differential patterns of performance were observed for the left and right TLE group across distinct face processing components. The left TLE group showed a selective impairment in naming famous faces while they performed similar to the controls in face recognition and semantic identification (i.e. occupation). In contrast, the right TLE group was impaired across all components of face memory; face recognition, semantic identification, and face naming. Face naming impairment in the left TLE group was characterized by a temporal gradient with better naming performance for famous faces from more distant time periods. Findings are discussed in terms of the role of the temporal lobe system for the acquisition, retention, and retrieval of face semantic networks, and the differential effects of lateralized temporal lobe lesions in this process.

Visual Memory in Post-Anterior Right Temporal Lobectomy Patients and Adult Normative Data for the Brown Location Test (BLT)

PubMed Central

Brown, Franklin C.; Tuttle, Erin; Westerveld, Michael; Ferraro, F. Richard; Chmielowiec, Teresa; Vandemore, Michelle; Gibson-Beverly, Gina; Bemus, Lisa; Roth, Robert M.; Blumenfeld, Hal; Spencer, Dennis D.; Spencer, Susan S

2010-01-01

Several large and meta-analytic studies have failed to support a consistent relationship between visual or “nonverbal” memory deficits and right mesial temporal lobe changes. However, the Brown Location Test (BLT) is a recently developed dot location learning and memory test that uses a nonsymmetrical array and provides control over many of the confounding variables (e.g., verbal influence and drawing requirements) inherent in other measures of visual memory. In the present investigation, we evaluated the clinical utility of the BLT in patients who had undergone left or right anterior mesial temporal lobectomies. We also provide adult normative data of 298 healthy adults in order to provide standardized scores. Results revealed significantly worse performance on the BLT in the right as compared to left lobectomy group and the healthy adult normative sample. The present findings support a role for the right anterior-mesial temporal lobe in dot location learning and memory. PMID:20056493

Interictal epileptiform discharges induce hippocampal-cortical coupling in temporal lobe epilepsy

PubMed Central

Gelinas, Jennifer N.; Khodagholy, Dion; Thesen, Thomas; Devinsky, Orrin; Buzsáki, György

2016-01-01

Interactions between the hippocampus and cortex are critical for memory. Interictal epileptiform discharges (IEDs) identify epileptic brain regions and can impair memory, but how they interact with physiological patterns of network activity is mostly undefined. We show in a rat model of temporal lobe epilepsy that spontaneous hippocampal IEDs correlate with impaired memory consolidation and are precisely coordinated with spindle oscillations in the prefrontal cortex during NREM sleep. This coordination surpasses the normal physiological ripple-spindle coupling and is accompanied by decreased ripple occurrence. IEDs also induce spindles during REM sleep and wakefulness, behavioral states that do not naturally express these oscillations, by generating a cortical ‘DOWN’ state. We confirm a similar correlation of temporofrontal IEDs with spindles over anatomically restricted cortical regions in a pilot clinical examination of four subjects with focal epilepsy. These findings imply that IEDs may impair memory via misappropriation of physiological mechanisms for hippocampal-cortical coupling, suggesting a target to treat memory impairment in epilepsy. PMID:27111281

Dynamic frontotemporal systems process space and time in working memory

PubMed Central

Adams, Jenna N.; Solbakk, Anne-Kristin; Endestad, Tor; Larsson, Pål G.; Ivanovic, Jugoslav; Meling, Torstein R.; Lin, Jack J.; Knight, Robert T.

2018-01-01

How do we rapidly process incoming streams of information in working memory, a cognitive mechanism central to human behavior? Dominant views of working memory focus on the prefrontal cortex (PFC), but human hippocampal recordings provide a neurophysiological signature distinct from the PFC. Are these regions independent, or do they interact in the service of working memory? We addressed this core issue in behavior by recording directly from frontotemporal sites in humans performing a visuospatial working memory task that operationalizes the types of identity and spatiotemporal information we encounter every day. Theta band oscillations drove bidirectional interactions between the PFC and medial temporal lobe (MTL; including the hippocampus). MTL theta oscillations directed the PFC preferentially during the processing of spatiotemporal information, while PFC theta oscillations directed the MTL for all types of information being processed in working memory. These findings reveal an MTL theta mechanism for processing space and time and a domain-general PFC theta mechanism, providing evidence that rapid, dynamic MTL–PFC interactions underlie working memory for everyday experiences. PMID:29601574

A Novel Approach to Primary Cell Culture for Octopus vulgaris Neurons

PubMed Central

Maselli, Valeria; Xu, Fenglian; Syed, Naweed I.; Polese, Gianluca; Di Cosmo, Anna

2018-01-01

Octopus vulgaris is a unique model system for studying complex behaviors in animals. It has a large and centralized nervous system made up of lobes that are involved in controlling various sophisticated behaviors. As such, it may be considered as a model organism for untangling the neuronal mechanisms underlying behaviors—including learning and memory. However, despite considerable efforts, Octopus lags behind its other counterparts vis-à-vis its utility in deciphering the cellular, molecular and synaptic mechanisms underlying various behaviors. This study represents a novel approach designed to establish a neuronal cell culture protocol that makes this species amenable to further exploitation as a model system. Here we developed a protocol that enables dissociation of neurons from two specific Octopus' brain regions, the vertical-superior frontal system and the optic lobes, which are involved in memory, learning, sensory integration and adult neurogenesis. In particular, cells dissociated with enzyme papain and cultured on Poly-D-Lysine-coated dishes with L15-medium and fetal bovine serum yielded high neuronal survival, axon growth, and re-growth after injury. This model was also explored to define optimal culture conditions and to demonstrate the regenerative capabilities of adult Octopus neurons after axotomy. This study thus further underscores the importance of Octopus neurons as a model system for deciphering fundamental molecular and cellular mechanism of complex brain function and underlying behaviors. PMID:29666582

Decoding Overlapping Memories in the Medial Temporal Lobes Using High-Resolution fMRI

ERIC Educational Resources Information Center

Chadwick, Martin J.; Hassabis, Demis; Maguire, Eleanor A.

2011-01-01

The hippocampus is proposed to process overlapping episodes as discrete memory traces, although direct evidence for this in human episodic memory is scarce. Using green-screen technology we created four highly overlapping movies of everyday events. Participants were scanned using high-resolution fMRI while recalling the movies. Multivariate…

Encoding-related brain activity during deep processing of verbal materials: a PET study.

PubMed

Fujii, Toshikatsu; Okuda, Jiro; Tsukiura, Takashi; Ohtake, Hiroya; Suzuki, Maki; Kawashima, Ryuta; Itoh, Masatoshi; Fukuda, Hiroshi; Yamadori, Atsushi

2002-12-01

The recent advent of neuroimaging techniques provides an opportunity to examine brain regions related to a specific memory process such as episodic memory encoding. There is, however, a possibility that areas active during an assumed episodic memory encoding task, compared with a control task, involve not only areas directly relevant to episodic memory encoding processes but also areas associated with other cognitive processes for on-line information. We used positron emission tomography (PET) to differentiate these two kinds of regions. Normal volunteers were engaged in deep (semantic) or shallow (phonological) processing of new or repeated words during PET. Results showed that deep processing, compared with shallow processing, resulted in significantly better recognition performance and that this effect was associated with activation of various brain areas. Further analyses revealed that there were regions directly relevant to episodic memory encoding in the anterior part of the parahippocampal gyrus, inferior frontal gyrus, supramarginal gyrus, anterior cingulate gyrus, and medial frontal lobe in the left hemisphere. Our results demonstrated that several regions, including the medial temporal lobe, play a role in episodic memory encoding.

Cognitive consequences of coexisting temporal lobe developmental malformations and hippocampal sclerosis.

PubMed

Martin, R; Dowler, R; Gilliam, F; Faught, E; Morawetz, R; Kuzniecky, R

1999-09-11

To characterize patterns of cognitive functioning in a well-defined group of patients with MRI-identified coexisting left temporal lobe developmental malformations (TLDM) and mesial temporal sclerosis (MTS), and to examine neuropsychological outcome in this dual-pathology group following epilepsy surgery. Cognitive functioning in patients with left TLDM and MTS (n = 15) was compared with patients with isolated left MTS (n = 40). TLDM and MTS were identified by high-quality MRI protocol. Patients were administered a battery of neuropsychology tests as part of their presurgical workup for possible epilepsy surgery. Unilateral temporal lobe resection was performed on 10 of the dual-pathology patients and 34 of the isolated MTS patients. Postoperative cognitive performance was also assessed. Both groups displayed impairments in verbal and visual memory, language, and academic achievement. Performance on measures of psychometric intelligence, executive function, and attention were not impaired and were similar between groups. Presence of dual pathology was associated with a significantly less efficient verbal encoding strategy on the word list learning task. Postoperatively, declines were noted for both groups across tasks of verbal memory and language. Groups were not different significantly in terms of neuropsychological outcome after surgery. Patients with coexisting TLDM and MTS have impaired cognitive functioning similar to MTS patients-in particular, with regard to episodic memory and language deficits. Temporal lobe resection produces similar cognitive changes in both groups.

The role of the human hippocampus in familiarity-based and recollection-based recognition memory

PubMed Central

Wixted, John T.; Squire, Larry R.

2010-01-01

The ability to recognize a previously encountered stimulus is dependent on the structures of the medial temporal lobe and is thought to be supported by two processes, recollection and familiarity. A focus of research in recent years concerns the extent to which these two processes depend on the hippocampus and on the other structures of the medial temporal lobe. One view holds that the hippocampus is important for both processes, whereas a different view holds that the hippocampus supports only the recollection process and the perirhinal cortex supports the familiarity process. One approach has been to study patients with hippocampal lesions and to contrast old/new recognition (which can be supported by familiarity) to free recall (which is supported by recollection). Despite some early case studies suggesting otherwise, several group studies have now shown that hippocampal patients exhibit comparable impairments on old/new recognition and free recall. These findings suggest that the hippocampus is important for both recollection and familiarity. Neuroimaging studies and Receiver Operating Characteristic analyses also initially suggested that the hippocampus was specialized for recollection, but these studies involved a strength confound (strong memories have been compared to weak memories). When steps are taken to compare strong recollection-based memories with strong familiarity-based memories, or otherwise control for memory strength, evidence for a familiarity signal (as well as a recollection signal) is evident in the hippocampus. These findings suggest that the functional organization of the medial temporal lobe is probably best understood in terms unrelated to the distinction between recollection and familiarity. PMID:20412819

Neural Correlates of Confidence during Item Recognition and Source Memory Retrieval: Evidence for Both Dual-Process and Strength Memory Theories

ERIC Educational Resources Information Center

Hayes, Scott M.; Buchler, Norbou; Stokes, Jared; Kragel, James; Cabeza, Roberto

2011-01-01

Although the medial-temporal lobes (MTL), PFC, and parietal cortex are considered primary nodes in the episodic memory network, there is much debate regarding the contributions of MTL, PFC, and parietal subregions to recollection versus familiarity (dual-process theory) and the feasibility of accounts on the basis of a single memory strength…

Working memory, long-term memory, and medial temporal lobe function

PubMed Central

Jeneson, Annette; Squire, Larry R.

2012-01-01

Early studies of memory-impaired patients with medial temporal lobe (MTL) damage led to the view that the hippocampus and related MTL structures are involved in the formation of long-term memory and that immediate memory and working memory are independent of these structures. This traditional idea has recently been revisited. Impaired performance in patients with MTL lesions on tasks with short retention intervals, or no retention interval, and neuroimaging findings with similar tasks have been interpreted to mean that the MTL is sometimes needed for working memory and possibly even for visual perception itself. We present a reappraisal of this interpretation. Our main conclusion is that, if the material to be learned exceeds working memory capacity, if the material is difficult to rehearse, or if attention is diverted, performance depends on long-term memory even when the retention interval is brief. This fundamental notion is better captured by the terms subspan memory and supraspan memory than by the terms short-term memory and long-term memory. We propose methods for determining when performance on short-delay tasks must depend on long-term (supraspan) memory and suggest that MTL lesions impair performance only when immediate memory and working memory are insufficient to support performance. In neuroimaging studies, MTL activity during encoding is influenced by the memory load and correlates positively with long-term retention of the material that was presented. The most parsimonious and consistent interpretation of all the data is that subspan memoranda are supported by immediate memory and working memory and are independent of the MTL. PMID:22180053

Alteration of functional connectivity within visuospatial working memory-related brain network in patients with right temporal lobe epilepsy: a resting-state fMRI study.

PubMed

Lv, Zong-xia; Huang, Dong-Hong; Ye, Wei; Chen, Zi-rong; Huang, Wen-li; Zheng, Jin-ou

2014-06-01

This study aimed to investigate the resting-state brain network related to visuospatial working memory (VSWM) in patients with right temporal lobe epilepsy (rTLE). The functional mechanism underlying the cognitive impairment in VSWM was also determined. Fifteen patients with rTLE and 16 healthy controls matched for age, gender, and handedness underwent a 6-min resting-state functional MRI session and a neuropsychological test using VSWM_Nback. The VSWM-related brain network at rest was extracted using multiple independent component analysis; the spatial distribution and the functional connectivity (FC) parameters of the cerebral network were compared between groups. Behavioral data were subsequently correlated with the mean Z-value in voxels showing significant FC difference during intergroup comparison. The distribution of the VSWM-related resting-state network (RSN) in the group with rTLE was virtually consistent with that in the healthy controls. The distribution involved the dorsolateral prefrontal lobe and parietal lobe in the right hemisphere and the partial inferior parietal lobe and posterior lobe of the cerebellum in the left hemisphere (p<0.05, AlphaSim corrected). Between-group differences suggest that the group with rTLE had a decreased FC within the right superior frontal lobe (BA8), right middle frontal lobe, and right ventromedial prefrontal lobe compared with the controls (p<0.05, AlphaSim corrected). The regions of increased FC in rTLE were localized within the right superior frontal lobe (BA11), right superior parietal lobe, and left posterior lobe of the cerebellum (p<0.05, AlphaSim corrected). Moreover, patients with rTLE performed worse than controls in the VSWM_Nback test, and there were negative correlations between ACCmeanRT (2-back) and the mean Z-value in the voxels showing decreased or increased FC in rTLE (p<0.05). The results suggest that the alteration of the VSWM-related RSN might underpin the VSWM impairment in patients with rTLE and possibly implies a functional compensation by enlarging the FC within the ipsilateral cerebral network. Copyright © 2014 Elsevier Inc. All rights reserved.

Adaptation to Cognitive Context and Item Information in the Medial Temporal Lobes

ERIC Educational Resources Information Center

Diana, Rachel A.; Yonelinas, Andrew P.; Ranganath, Charan

2012-01-01

The medial temporal lobes (MTL) play an essential role in episodic memory, and accumulating evidence indicates that two MTL subregions--the perirhinal (PRc) and parahippocampal (PHc) cortices--might have different functions. According to the binding of item and context theory ( [16] and [21]), PRc is involved in processing item information, the…

A Case Study of the Cognitive and Behavioral Deficits of Temporal Lobe Damage in Herpes Simplex Encephalitis.

ERIC Educational Resources Information Center

Greer, Margaret K.; And Others

1989-01-01

This case study illustrates the highly significant language difficulties, marked memory deficits, and propensity for physical aggression following temporal lobe damage brought about by herpes encephalitis, and presents the usefulness of a new diagnostic measure in delineating such a variable cognitive pattern. (Author)

Time Ordering in Frontal Lobe Patients: A Stochastic Model Approach

ERIC Educational Resources Information Center

Magherini, Anna; Saetti, Maria Cristina; Berta, Emilia; Botti, Claudio; Faglioni, Pietro

2005-01-01

Frontal lobe patients reproduced a sequence of capital letters or abstract shapes. Immediate and delayed reproduction trials allowed the analysis of short- and long-term memory for time order by means of suitable Markov chain stochastic models. Patients were as proficient as healthy subjects on the immediate reproduction trial, thus showing spared…

Anterior Medial Temporal Lobe Activation during Encoding of Words: FMRI Methods to Optimize Sensitivity

ERIC Educational Resources Information Center

Parsons, Michael W.; Haut, Marc W.; Lemieux, Susan K.; Moran, Maria T.; Leach, Sharon G.

2006-01-01

The existence of a rostrocaudal gradient of medial temporal lobe (MTL) activation during memory encoding has historically received support from positron emission tomography studies, but less so from functional MRI (FMRI) studies. More recently, FMRI studies have demonstrated that characteristics of the stimuli can affect the location of activation…

Short-Term Memory for Space and Time Flexibly Recruit Complementary Sensory-Biased Frontal Lobe Attention Networks.

PubMed

Michalka, Samantha W; Kong, Lingqiang; Rosen, Maya L; Shinn-Cunningham, Barbara G; Somers, David C

2015-08-19

The frontal lobes control wide-ranging cognitive functions; however, functional subdivisions of human frontal cortex are only coarsely mapped. Here, functional magnetic resonance imaging reveals two distinct visual-biased attention regions in lateral frontal cortex, superior precentral sulcus (sPCS) and inferior precentral sulcus (iPCS), anatomically interdigitated with two auditory-biased attention regions, transverse gyrus intersecting precentral sulcus (tgPCS) and caudal inferior frontal sulcus (cIFS). Intrinsic functional connectivity analysis demonstrates that sPCS and iPCS fall within a broad visual-attention network, while tgPCS and cIFS fall within a broad auditory-attention network. Interestingly, we observe that spatial and temporal short-term memory (STM), respectively, recruit visual and auditory attention networks in the frontal lobe, independent of sensory modality. These findings not only demonstrate that both sensory modality and information domain influence frontal lobe functional organization, they also demonstrate that spatial processing co-localizes with visual processing and that temporal processing co-localizes with auditory processing in lateral frontal cortex. Copyright © 2015 Elsevier Inc. All rights reserved.

Contributions of volumetrics of the hippocampus and thalamus to verbal memory in temporal lobe epilepsy patients.

PubMed

Stewart, Christopher C; Griffith, H Randall; Okonkwo, Ozioma C; Martin, Roy C; Knowlton, Robert K; Richardson, Elizabeth J; Hermann, Bruce P; Seidenberg, Michael

2009-02-01

Recent theories have posited that the hippocampus and thalamus serve distinct, yet related, roles in episodic memory. Whereas the hippocampus has been implicated in long-term memory encoding and storage, the thalamus, as a whole, has been implicated in the selection of items for subsequent encoding and the use of retrieval strategies. However, dissociating the memory impairment that occurs following thalamic injury as distinguished from that following hippocampal injury has proven difficult. This study examined relationships between MRI volumetric measures of the hippocampus and thalamus and their contributions to prose and rote verbal memory functioning in 18 patients with intractable temporal lobe epilepsy (TLE). Results revealed that bilateral hippocampal and thalamic volume independently predicted delayed prose verbal memory functioning. However, bilateral hippocampal, but not thalamic, volume predicted delayed rote verbal memory functioning. Follow-up analyses indicated that bilateral thalamic volume independently predicted immediate prose, but not immediate rote, verbal recall, whereas bilateral hippocampal volume was not associated with any of these immediate memory measures. These findings underscore the cognitive significance of thalamic atrophy in chronic TLE, demonstrating that hippocampal and thalamic volume make quantitatively, and perhaps qualitatively, distinct contributions to episodic memory functioning in TLE patients. They are also consistent with theories proposing that the hippocampus supports long-term memory encoding and storage, whereas the thalamus is implicated in the executive aspects of episodic memory.

Top-down and bottom-up attention to memory: a hypothesis (AtoM) on the role of the posterior parietal cortex in memory retrieval.

PubMed

Ciaramelli, Elisa; Grady, Cheryl L; Moscovitch, Morris

2008-01-01

Recent neuroimaging studies have implicated the posterior parietal cortex in episodic memory retrieval, but there is uncertainty about its specific role. Research in the attentional domain has shown that superior parietal lobe (SPL) regions along the intraparietal sulcus are implicated in the voluntary orienting of attention to relevant aspects of the environment, whereas inferior parietal lobe (IPL) regions at the temporo-parietal junction mediate the automatic allocation of attention to task-relevant information. Here we propose that the SPL and the IPL play conceptually similar roles in episodic memory retrieval. We hypothesize that the SPL allocates top-down attention to memory retrieval, whereas the IPL mediates the automatic, bottom-up attentional capture by retrieved memory contents. By reviewing the existing fMRI literature, we show that the posterior intraparietal sulcus of SPL is consistently active when the need for top-down assistance to memory retrieval is supposedly maximal, e.g., for memories retrieved with low vs. high confidence, for familiar vs. recollected memories, for recognition of high vs. low frequency words. On the other hand, the supramarginal gyrus of IPL is consistently active when the attentional capture by memory contents is supposedly maximal, i.e., for strong vs. weak memories, for vividly recollected vs. familiar memories, for memories retrieved with high vs. low confidence. We introduce a model of episodic memory retrieval that characterizes contributions of posterior parietal cortex.

Recognition memory span in autopsy-confirmed Dementia with Lewy Bodies and Alzheimer's Disease.

PubMed

Salmon, David P; Heindel, William C; Hamilton, Joanne M; Vincent Filoteo, J; Cidambi, Varun; Hansen, Lawrence A; Masliah, Eliezer; Galasko, Douglas

2015-08-01

Evidence from patients with amnesia suggests that recognition memory span tasks engage both long-term memory (i.e., secondary memory) processes mediated by the diencephalic-medial temporal lobe memory system and working memory processes mediated by fronto-striatal systems. Thus, the recognition memory span task may be particularly effective for detecting memory deficits in disorders that disrupt both memory systems. The presence of unique pathology in fronto-striatal circuits in Dementia with Lewy Bodies (DLB) compared to AD suggests that performance on the recognition memory span task might be differentially affected in the two disorders even though they have quantitatively similar deficits in secondary memory. In the present study, patients with autopsy-confirmed DLB or AD, and Normal Control (NC) participants, were tested on separate recognition memory span tasks that required them to retain increasing amounts of verbal, spatial, or visual object (i.e., faces) information across trials. Results showed that recognition memory spans for verbal and spatial stimuli, but not face stimuli, were lower in patients with DLB than in those with AD, and more impaired relative to NC performance. This was despite similar deficits in the two patient groups on independent measures of secondary memory such as the total number of words recalled from long-term storage on the Buschke Selective Reminding Test. The disproportionate vulnerability of recognition memory span task performance in DLB compared to AD may be due to greater fronto-striatal involvement in DLB and a corresponding decrement in cooperative interaction between working memory and secondary memory processes. Assessment of recognition memory span may contribute to the ability to distinguish between DLB and AD relatively early in the course of disease. Copyright © 2015 Elsevier Ltd. All rights reserved.

Recognition Memory Span in Autopsy-Confirmed Dementia with Lewy Bodies and Alzheimer’s Disease

PubMed Central

Salmon, David P.; Heindel, William C.; Hamilton, Joanne M.; Filoteo, J. Vincent; Cidambi, Varun; Hansen, Lawrence A.; Masliah, Eliezer; Galasko, Douglas

2016-01-01

Evidence from patients with amnesia suggests that recognition memory span tasks engage both long-term memory (i.e., secondary memory) processes mediated by the diencephalic-medial temporal lobe memory system and working memory processes mediated by fronto-striatal systems. Thus, the recognition memory span task may be particularly effective for detecting memory deficits in disorders that disrupt both memory systems. The presence of unique pathology in fronto-striatal circuits in Dementia with Lewy Bodies (DLB) compared to AD suggests that performance on the recognition memory span task might be differentially affected in the two disorders even though they have quantitatively similar deficits in secondary memory. In the present study, patients with autopsy-confirmed DLB or AD, and normal control (NC) participants, were tested on separate recognition memory span tasks that required them to retain increasing amounts of verbal, spatial, or visual object (i.e., faces) information across trials. Results showed that recognition memory spans for verbal and spatial stimuli, but not face stimuli, were lower in patients with DLB than in those with AD, and more impaired relative to NC performance. This was despite similar deficits in the two patient groups on independent measures of secondary memory such as the total number of words recalled from Long-Term Storage on the Buschke Selective Reminding Test. The disproportionate vulnerability of recognition memory span task performance in DLB compared to AD may be due to greater fronto-striatal involvement in DLB and a corresponding decrement in cooperative interaction between working memory and secondary memory processes. Assessment of recognition memory span may contribute to the ability to distinguish between DLB and AD relatively early in the course of disease. PMID:26184443

FMRI Is a Valid Noninvasive Alternative to Wada Testing

PubMed Central

Binder, Jeffrey R.

2010-01-01

Partial removal of the anterior temporal lobe (ATL) is a highly effective surgical treatment for intractable temporal lobe epilepsy, yet roughly half of patients who undergo left ATL resection show decline in language or verbal memory function postoperatively. Two recent studies demonstrate that preoperative fMRI can predict postoperative naming and verbal memory changes in such patients. Most importantly, fMRI significantly improves the accuracy of prediction relative to other noninvasive measures used alone. Addition of language and memory lateralization data from the intracarotid amobarbital (Wada) test did not improve prediction accuracy in these studies. Thus, fMRI provides patients and practitioners with a safe, non-invasive, and well-validated tool for making better-informed decisions regarding elective surgery based on a quantitative assessment of cognitive risk. PMID:20850386

Verbal learning and memory outcome in selective amygdalohippocampectomy versus temporal lobe resection in patients with hippocampal sclerosis.

PubMed

Foged, Mette Thrane; Vinter, Kirsten; Stauning, Louise; Kjær, Troels W; Ozenne, Brice; Beniczky, Sándor; Paulson, Olaf B; Madsen, Flemming Find; Pinborg, Lars H

2018-02-01

With the advent of new very selective techniques like thermal laser ablation to treat drug-resistant focal epilepsy, the controversy of resection size in relation to seizure outcome versus cognitive deficits has gained new relevance. The purpose of this study was to test the influence of the selective amygdalohippocampectomy (SAH) versus nonselective temporal lobe resection (TLR) on seizure outcome and cognition in patients with mesial temporal lobe epilepsy (MTLE) and histopathological verified hippocampal sclerosis (HS). We identified 108 adults (>16years) with HS, operated between 1995 and 2009 in Denmark. Exclusion criteria are the following: Intelligence below normal range, right hemisphere dominance, other native languages than Danish, dual pathology, and missing follow-up data. Thus, 56 patients were analyzed. The patients were allocated to SAH (n=22) or TLR (n=34) based on intraoperative electrocorticography. Verbal learning and verbal memory were tested pre- and postsurgery. Seizure outcome did not differ between patients operated using the SAH versus the TLR at 1year (p=0.951) nor at 7years (p=0.177). Verbal learning was more affected in patients resected in the left hemisphere than in the right (p=0.002). In patients with left-sided TLR, a worsening in verbal memory performance was found (p=0.011). Altogether, 73% were seizure-free for 1year and 64% for 7years after surgery. In patients with drug-resistant focal MTLE, HS and no magnetic resonance imaging (MRI) signs of dual pathology, selective amygdalohippocampectomy results in sustained seizure freedom and better memory function compared with patients operated with nonselective temporal lobe resection. Copyright © 2017 Elsevier Inc. All rights reserved.

Multimodal neuroimaging evidence linking memory and attention systems during visual search cued by context.

PubMed

Kasper, Ryan W; Grafton, Scott T; Eckstein, Miguel P; Giesbrecht, Barry

2015-03-01

Visual search can be facilitated by the learning of spatial configurations that predict the location of a target among distractors. Neuropsychological and functional magnetic resonance imaging (fMRI) evidence implicates the medial temporal lobe (MTL) memory system in this contextual cueing effect, and electroencephalography (EEG) studies have identified the involvement of visual cortical regions related to attention. This work investigated two questions: (1) how memory and attention systems are related in contextual cueing; and (2) how these systems are involved in both short- and long-term contextual learning. In one session, EEG and fMRI data were acquired simultaneously in a contextual cueing task. In a second session conducted 1 week later, EEG data were recorded in isolation. The fMRI results revealed MTL contextual modulations that were correlated with short- and long-term behavioral context enhancements and attention-related effects measured with EEG. An fMRI-seeded EEG source analysis revealed that the MTL contributed the most variance to the variability in the attention enhancements measured with EEG. These results support the notion that memory and attention systems interact to facilitate search when spatial context is implicitly learned. © 2015 New York Academy of Sciences.

Source Monitoring 15 Years Later: What Have We Learned from fMRI about the Neural Mechanisms of Source Memory?

ERIC Educational Resources Information Center

Mitchell, Karen J.; Johnson, Marcia K.

2009-01-01

Focusing primarily on functional magnetic resonance imaging (fMRI), this article reviews evidence regarding the roles of subregions of the medial temporal lobes, prefrontal cortex, posterior representational areas, and parietal cortex in source memory. In addition to evidence from standard episodic memory tasks assessing accuracy for neutral…

Spatial and Temporal Episodic Memory Retrieval Recruit Dissociable Functional Networks in the Human Brain

ERIC Educational Resources Information Center

Ekstrom, Arne D.; Bookheimer, Susan Y.

2007-01-01

Imaging, electrophysiological studies, and lesion work have shown that the medial temporal lobe (MTL) is important for episodic memory; however, it is unclear whether different MTL regions support the spatial, temporal, and item elements of episodic memory. In this study we used fMRI to examine retrieval performance emphasizing different aspects…

Internal Representation and Memory Formation of Odor Preference Based on Oscillatory Activities in a Terrestrial Slug

ERIC Educational Resources Information Center

Sekiguchi, Tatsuhiko; Furudate, Hiroyuki; Kimura, Tetsuya

2010-01-01

The terrestrial slug "Limax" exhibits a highly developed ability to learn odors with a small nervous system. When a fluorescent dye, Lucifer Yellow (LY), is injected into the slug's body cavity after odor-taste associative conditioning, a group of neurons in the procerebral (PC) lobe, an olfactory center of the slug, is labeled by LY. We examined…

The role of the basal ganglia in learning and memory: Insight from Parkinson's disease

PubMed Central

2013-01-01

It has long been known that memory is not a single process. Rather, there are different kinds of memory that are supported by distinct neural systems. This idea stemmed from early findings of dissociable patterns of memory impairments in patients with selective damage to different brain regions. These studies highlighted the role of the basal ganglia in non-declarative memory, such as procedural or habit learning, contrasting it with the known role of the medial temporal lobes in declarative memory. In recent years, major advances across multiple areas of neuroscience have revealed an important role for the basal ganglia in motivation and decision making. These findings have led to new discoveries about the role of the basal ganglia in learning and highlighted the essential role of dopamine in specific forms of learning. Here we review these recent advances with an emphasis on novel discoveries from studies of learning in patients with Parkinson's disease. We discuss how these findings promote the development of current theories away from accounts that emphasize the verbalizability of the contents of memory and towards a focus on the specific computations carried out by distinct brain regions. Finally, we discuss new challenges that arise in the face of accumulating evidence for dynamic and interconnected memory systems that jointly contribute to learning. PMID:21945835

The neuroscience of positive memory deficits in depression

PubMed Central

Dillon, Daniel G.

2015-01-01

Adults with unipolar depression typically show poor episodic memory for positive material, but the neuroscientific mechanisms responsible for this deficit have not been characterized. I suggest a simple hypothesis: weak memory for positive material in depression reflects disrupted communication between the mesolimbic dopamine pathway and medial temporal lobe (MTL) memory systems during encoding. This proposal draws on basic research showing that dopamine release in the hippocampus is critical for the transition from early- to late-phase long-term potentiation (LTP) that marks the conversion of labile, short-term memories into stable, long-term memories. Neuroimaging and pharmacological data from healthy humans paint a similar picture: activation of the mesolimbic reward circuit enhances encoding and boosts retention. Unipolar depression is characterized by anhedonia–loss of pleasure–and reward circuit dysfunction, which is believed to reflect negative effects of stress on the mesolimbic dopamine pathway. Thus, I propose that the MTL is deprived of strengthening reward signals in depressed adults and memory for positive events suffers accordingly. Although other mechanisms are important, this hypothesis holds promise as an explanation for positive memory deficits in depression. PMID:26441703

A critical evaluation of monkey models of amnesia and dementia.

PubMed

Ridley, R M; Baker, H F

1991-01-01

In this review we consider various models of amnesia and dementia in monkeys and examine the validity of such models. In Section 2 we describe the various types of memory tests (tasks) available for use with monkeys and discuss the extent to which these tasks assess different facets of memory according to present theories of human memory. We argue that the rules which govern correct task performance are best regarded as a form of semantic rather than procedural memory, and that when information about stimulus attributes or reward associations is stored long-term then that knowledge is semantic. The demonstration of episodic memory in monkeys is problematic and the term recognition memory has been used too loosely. In particular, it is difficult to dissociate episodic memory for stimulus events from the use of semantic memory for the rule of the task, since dysfunction of either can produce impairment on performance of the same task. Tasks can also be divided into those which assess memory for stimulus-reward associations (evaluative memory) and those which tax stimulus-response associations including spatial and conditional responding (non-evaluative memory). This dissociation cuts across the distinction between semantic and episodic memory. In Section 3 we examine the usefulness of the classification of tasks described in Section 2 in clarifying our understanding of the contribution of the temporal lobes and the cholinergic system to memory. We conclude that evaluative and non-evaluative memory are mediated by separate parallel systems involving the amygdala and hippocampus, respectively.

Stress as a mnemonic filter: Interactions between medial temporal lobe encoding processes and post-encoding stress

PubMed Central

Ritchey, Maureen; McCullough, Andrew M.; Ranganath, Charan; Yonelinas, Andrew P.

2016-01-01

Acute stress has been shown to modulate memory for recently learned information, an effect attributed to the influence of stress hormones on medial temporal lobe (MTL) consolidation processes. However, little is known about which memories will be affected when stress follows encoding. One possibility is that stress interacts with encoding processes to selectively protect memories that had elicited responses in the hippocampus and amygdala, two MTL structures important for memory formation. There is limited evidence for interactions between encoding processes and consolidation effects in humans, but recent studies of consolidation in rodents have emphasized the importance of encoding “tags” for determining the impact of consolidation manipulations on memory. Here, we used fMRI in humans to test the hypothesis that the effects of post-encoding stress depend on MTL processes observed during encoding. We found that changes in stress hormone levels were associated with an increase in the contingency of memory outcomes on hippocampal and amygdala encoding responses. That is, for participants showing high cortisol reactivity, memories became more dependent on MTL activity observed during encoding, thereby shifting the distribution of recollected events toward those that had elicited relatively high activation. Surprisingly, this effect was generally larger for neutral, compared to emotionally negative, memories. The results suggest that stress does not uniformly enhance memory, but instead selectively preserves memories tagged during encoding, effectively acting as mnemonic filter. PMID:27774683

Network analysis of brain activations in working memory: behavior and age relationships.

PubMed

Mencl, W E; Pugh, K R; Shaywitz, S E; Shaywitz, B A; Fulbright, R K; Constable, R T; Skudlarski, P; Katz, L; Marchione, K E; Lacadie, C; Gore, J C

2000-10-01

Forty-six middle-aged female subjects were scanned using functional Magnetic Resonance Imaging (fMRI) during performance of three distinct stages of a working memory task-encoding, rehearsal, and recognition-for both printed pseudowords and visual forms. An expanse of areas, involving the inferior frontal, parietal, and extrastriate cortex, was active in response to stimuli during both the encoding and recognition periods. Additional increases during memory recognition were seen in right prefrontal regions, replicating a now-common finding [for reviews, see Fletcher et al. (1997) Trends Neurosci 20:213-218; MacLeod et al. (1998) NeuroImage 7:41-48], and broadly supporting the Hemispheric Encoding/Retrieval Asymmetry hypothesis [Tulving et al. (1994) Proc Natl Acad Sci USA 91:2016-2020]. Notably, this asymmetry was not qualified by the type of material being processed. A few sites demonstrated higher activity levels during the rehearsal period, in the absence of any new stimuli, including the medial extrastriate, precuneus, and the medial temporal lobe. Further analyses examined relationships among subjects' brain activations, age, and behavioral scores on working memory tests, acquired outside the scanner. Correlations between brain scores and behavior scores indicated that activations in a number of areas, mainly frontal, were associated with performance. A multivariate analysis, Partial Least Squares [McIntosh et al. (1996) NeuroImage 3:143-157, (1997) Hum Brain Map 5:323-327], was then used to extract component effects from this large set of univariate correlations. Results indicated that better memory performance outside the scanner was associated with higher activity at specific sites within the frontal and, additionally, the medial temporal lobes. Analysis of age effects revealed that younger subjects tended to activate more than older subjects in areas of extrastriate cortex, medial frontal cortex, and the right medial temporal lobe; older subjects tended to activate more than younger subjects in the insular cortex, right inferior temporal lobe, and right inferior frontal gyrus. These results extend recent reports indicating that these regions are specifically involved in the memory impairments seen with aging. Copyright 2000 Wiley-Liss, Inc.

CE verbal episodic memory impairment in schizophrenia: a comparison with frontal lobe lesion patients.

PubMed

Christensen, Bruce K; Patrick, Regan E; Stuss, Donald T; Gillingham, Susan; Zipursky, Robert B

2013-01-01

Schizophrenia (SCZ)-related verbal memory impairment is hypothesized to be mediated, in part, by frontal lobe (FTL) dysfunction. However, little research has contrasted the performance of SCZ patients with that of patients exhibiting circumscribed frontal lesions. The current study compared verbal episodic memory in patients with SCZ and focal FTL lesions (left frontal, LF; right frontal, RF; and bi-frontal, BF) on a four-trial list learning task consisting of three lists of varying semantic organizational structure. Each dependent variable was examined at two levels: scores collapsed across all four trials and learning scores (i.e., trial 4-trial 1). Performance deficits were observed in each patient group across most dependent measures at both levels. Regarding patient group differences, SCZ patients outperformed LF/BF patients (i.e., either learning scores or scores collapsed across trial) on free recall, primacy, primary memory, secondary memory, and subjective organization, whereas they only outperformed RF patients on the semantically blocked list on recency and primary memory. Collectively, these results indicate that the pattern of memory performance is largely similar between patients with SCZ and those with RF lesions. These data support tentative arguments that verbal episodic memory deficits in SCZ may be mediated by frontal dysfunction in the right hemisphere.

Influence of anxiety on memory performance in temporal lobe epilepsy.

PubMed

Brown, Franklin C; Westerveld, Michael; Langfitt, John T; Hamberger, Marla; Hamid, Hamada; Shinnar, Shlomo; Sperling, Michael R; Devinsky, Orrin; Barr, William; Tracy, Joseph; Masur, David; Bazil, Carl W; Spencer, Susan S

2014-02-01

This study examined the degree to which anxiety contributed to inconsistent material-specific memory difficulties among 243 patients with temporal lobe epilepsy from the Multisite Epilepsy Study. Visual memory performance on the Rey Complex Figure Test (RCFT) was poorer for those with high versus low levels of anxiety but was not found to be related to the TLE side. The verbal memory score on the California Verbal Learning Test (CVLT) was significantly lower for patients with left-sided TLE than for patients with right-sided TLE with low anxiety levels but equally impaired for those with high anxiety levels. These results suggest that we can place more confidence in the ability of verbal memory tests like the CVLT to lateralize to left-sided TLE for those with low anxiety levels, but that verbal memory will be less likely to produce lateralizing information for those with high anxiety levels. This suggests that more caution is needed when interpreting verbal memory tests for those with high anxiety levels. These results indicated that RCFT performance was significantly affected by anxiety and did not lateralize to either side, regardless of anxiety levels. This study adds to the existing literature which suggests that drawing-based visual memory tests do not lateralize among patients with TLE, regardless of anxiety levels. © 2013.

Medial temporal lobe structure and cognition in individuals with schizophrenia and in their non-psychotic siblings.

PubMed

Karnik-Henry, Meghana S; Wang, Lei; Barch, Deanna M; Harms, Michael P; Campanella, Carolina; Csernansky, John G

2012-07-01

Medial temporal lobe (MTL) structures play a central role in episodic memory. Prior studies suggest that individuals with schizophrenia have deficits in episodic memory as well as structural abnormalities of the medial temporal lobe (MTL). While correlations have been reported between MTL volume loss and episodic memory deficits in such individuals, it is not clear whether such correlations reflect the influence of the disease state or of underlying genetic influences that might contribute to risk. We used high resolution magnetic resonance imaging and probabilistic algorithms for image analysis to determine whether MTL structure, episodic memory performance and the relationship between the two differed among groups of 47 healthy control subjects, 50 control siblings, 39 schizophrenia subjects, and 33 siblings of schizophrenia subjects. High-dimensional large deformation brain mapping was used to obtain volume measures of the hippocampus. Cortical distance mapping was used to obtain volume and thickness measures of the parahippocampal gyrus (PHG) and its substructures: the entorhinal cortex (ERC), the perirhinal cortex (PRC), and the parahippocampal cortex (PHC). Neuropsychological data was used to establish an episodic memory domain score for each subject. Both schizophrenia subjects and their siblings displayed abnormalities in episodic memory performance. Siblings of individuals with schizophrenia, and to a lesser extent, individuals with schizophrenia themselves, displayed abnormalities in measures of MTL structure (volume loss or cortical thinning) as compared to control groups. Further, we observed correlations between structural measures and memory performance in both schizophrenia subjects and their siblings, but not in their respective control groups. These findings suggest that disease-specific genetic factors present in both patients and their relatives may be responsible for correlated abnormalities of MTL structure and memory impairment. The observed attenuated effect of such factors on MTL structure in individuals with schizophrenia may be due to non-genetic influences related to the development and progression of the disease on global brain structure and cognitive processing. Copyright © 2012 Elsevier B.V. All rights reserved.

Selective Familiarity Deficits after Left Anterior Temporal-Lobe Removal with Hippocampal Sparing Are Material Specific

ERIC Educational Resources Information Center

Martin, Chris B.; Bowles, Ben; Mirsattari, Seyed M.; Kohler, Stefan

2011-01-01

Research has firmly established a link between recognition memory and the functional integrity of the medial temporal lobes (MTL). Dual-process models of MTL organization maintain that there is a division of labour within the MTL, with the hippocampus (HC) supporting recollective processes and perirhinal cortex (PRc) supporting familiarity…

Network Alterations Supporting Word Retrieval in Patients with Medial Temporal Lobe Epilepsy

ERIC Educational Resources Information Center

Protzner, Andrea B.; McAndrews, Mary Pat

2011-01-01

Although the hippocampus is not considered a key structure in semantic memory, patients with medial-temporal lobe epilepsy (mTLE) have deficits in semantic access on some word retrieval tasks. We hypothesized that these deficits reflect the negative impact of focal epilepsy on remote cerebral structures. Thus, we expected that the networks that…

Divergent Task Performance in Older Adults: Declarative Memory or Creative Potential?

ERIC Educational Resources Information Center

Leon, Susan A.; Altmann, Lori J. P.; Abrams, Lise; Gonzalez Rothi, Leslie J.; Heilman, Kenneth M.

2014-01-01

Divergent thinking is a process or method used to generate creative ideas by exploring many possible solutions or responses, and is a critical element of creativity. Lesion and imaging studies have shown that the frontal lobes are important in mediating divergent thinking, and frontal lobe function is highly dependent on white matter connections…

Experience-near but not experience-far autobiographical facts depend on the medial temporal lobe for retrieval: Evidence from amnesia

PubMed Central

Grilli, Matthew D.; Verfaellie, Mieke

2015-01-01

This paper addresses the idea that there may be two types of autobiographical facts with distinct cognitive and neural mechanisms: “Experience-near” autobiographical facts, which contain spatiotemporal content derived from personal experience and thus depend on the medial temporal lobe (MTL) for retrieval, and “experience-far” autobiographical facts, which are abstract memories and thus rely on neocortical brain regions involved in retrieval of general semantic memory. To investigate this conceptual model of autobiographical fact knowledge, we analyzed the nature of autobiographical facts that were generated by 8 individuals with MTL amnesia and 12 control participants in a recent study of identity and memory [Grilli, M.D., & Verfaellie, M. (2015). Supporting the self-concept with memory: insight from amnesia. Social Cognitive and Affective Neuroscience, 10, 1684–1692]. Results revealed that MTL amnesic participants generated fewer experience-near autobiographical facts than controls. Experience-far autobiographical fact generation was not impaired in amnesic participants with damage restricted to the MTL, but there was preliminary evidence to suggest that it may be impaired in amnesic participants with damage to the MTL and anterior lateral temporal lobe. These results support a cognitive and neural distinction between experience-near and experience-far autobiographical facts and have implications for understanding the contribution of autobiographical fact knowledge to self-related cognition. PMID:26721761

Experience-near but not experience-far autobiographical facts depend on the medial temporal lobe for retrieval: Evidence from amnesia.

PubMed

Grilli, Matthew D; Verfaellie, Mieke

2016-01-29

This paper addresses the idea that there may be two types of autobiographical facts with distinct cognitive and neural mechanisms: "Experience-near" autobiographical facts, which contain spatiotemporal content derived from personal experience and thus depend on the medial temporal lobe (MTL) for retrieval, and "experience-far" autobiographical facts, which are abstract memories and thus rely on neocortical brain regions involved in retrieval of general semantic memory. To investigate this conceptual model of autobiographical fact knowledge, we analyzed the nature of autobiographical facts that were generated by 8 individuals with MTL amnesia and 12 control participants in a recent study of identity and memory [Grilli, M.D., & Verfaellie, M. (2015). Supporting the self-concept with memory: insight from amnesia. Social Cognitive and Affective Neuroscience, 10, 1684-1692]. Results revealed that MTL amnesic participants generated fewer experience-near autobiographical facts than controls. Experience-far autobiographical fact generation was not impaired in amnesic participants with damage restricted to the MTL, but there was preliminary evidence to suggest that it may be impaired in amnesic participants with damage to the MTL and anterior lateral temporal lobe. These results support a cognitive and neural distinction between experience-near and experience-far autobiographical facts and have implications for understanding the contribution of autobiographical fact knowledge to self-related cognition. Published by Elsevier Ltd.

The functional neuroanatomy of language

NASA Astrophysics Data System (ADS)

Hickok, Gregory

2009-09-01

There has been substantial progress over the last several years in understanding aspects of the functional neuroanatomy of language. Some of these advances are summarized in this review. It will be argued that recognizing speech sounds is carried out in the superior temporal lobe bilaterally, that the superior temporal sulcus bilaterally is involved in phonological-level aspects of this process, that the frontal/motor system is not central to speech recognition although it may modulate auditory perception of speech, that conceptual access mechanisms are likely located in the lateral posterior temporal lobe (middle and inferior temporal gyri), that speech production involves sensory-related systems in the posterior superior temporal lobe in the left hemisphere, that the interface between perceptual and motor systems is supported by a sensory-motor circuit for vocal tract actions (not dedicated to speech) that is very similar to sensory-motor circuits found in primate parietal lobe, and that verbal short-term memory can be understood as an emergent property of this sensory-motor circuit. These observations are considered within the context of a dual stream model of speech processing in which one pathway supports speech comprehension and the other supports sensory-motor integration. Additional topics of discussion include the functional organization of the planum temporale for spatial hearing and speech-related sensory-motor processes, the anatomical and functional basis of a form of acquired language disorder, conduction aphasia, the neural basis of vocabulary development, and sentence-level/grammatical processing.

Impaired familiarity with preserved recollection after anterior temporal-lobe resection that spares the hippocampus.

PubMed

Bowles, Ben; Crupi, Carina; Mirsattari, Seyed M; Pigott, Susan E; Parrent, Andrew G; Pruessner, Jens C; Yonelinas, Andrew P; Köhler, Stefan

2007-10-09

It is well established that the medial-temporal lobe (MTL) is critical for recognition memory. The MTL is known to be composed of distinct structures that are organized in a hierarchical manner. At present, it remains controversial whether lower structures in this hierarchy, such as perirhinal cortex, support memory functions that are distinct from those of higher structures, in particular the hippocampus. Perirhinal cortex has been proposed to play a specific role in the assessment of familiarity during recognition, which can be distinguished from the selective contributions of the hippocampus to the recollection of episodic detail. Some researchers have argued, however, that the distinction between familiarity and recollection cannot capture functional specialization within the MTL and have proposed single-process accounts. Evidence supporting the dual-process view comes from demonstrations that selective hippocampal damage can produce isolated recollection impairments. It is unclear, however, whether temporal-lobe lesions that spare the hippocampus can produce selective familiarity impairments. Without this demonstration, single-process accounts cannot be ruled out. We examined recognition memory in NB, an individual who underwent surgical resection of left anterior temporal-lobe structures for treatment of intractable epilepsy. Her resection included a large portion of perirhinal cortex but spared the hippocampus. The results of four experiments based on three different experimental procedures (remember-know paradigm, receiver operating characteristics, and response-deadline procedure) indicate that NB exhibits impaired familiarity with preserved recollection. The present findings thus provide a crucial missing piece of support for functional specialization in the MTL.

Disturbance of time orientation, attention, and verbal memory in amnesic patients with confabulation.

PubMed

Shingaki, Honoka; Park, Paeksoon; Ueda, Keita; Murai, Toshiya; Tsukiura, Takashi

2016-01-01

Confabulation is often observed in amnesic patients after brain damage. However, evidence regarding the relationship between confabulation and other neuropsychological functions is scarce. In addition, previous studies have proposed two possibilities of the relationship between confabulation and false memory, in which patients with confabulation are likely to retrieve false memories, or confabulations are relatively independent of false memories. The present study investigated how confabulation is related to various cognitive functions, including orientation, attention, frontal lobe function, memory, and mental status, and to false memories, as assessed by the Deese-Roediger-Mcdermott (DRM) paradigm. Patients with organic amnesia participated, and confabulations were evaluated using the Confabulation Battery. Amnestic patients were classified into two groups: confabulating (CP) and nonconfabulating patients (NCP). The CP group was significantly impaired in time orientation, attention, and verbal memory, compared to the NCP group and age-matched healthy controls (HC). Results of the DRM paradigm revealed no significant difference in false memory retrieval induced by critical lures across CP, NCP, and HC groups. Confabulating responses in organic amnesia could be in part induced by disturbance of time consciousness and attention control in severe impairment of verbal memories, and confabulation and false memory could be modulated by different cognitive systems.

Evoked Potentials and Memory/Cognition Tests Validate Brain Atrophy as Measured by 3T MRI (NeuroQuant) in Cognitively Impaired Patients.

PubMed

Braverman, Eric R; Blum, Kenneth; Hussman, Karl L; Han, David; Dushaj, Kristina; Li, Mona; Marin, Gabriela; Badgaiyan, Rajendra D; Smayda, Richard; Gold, Mark S

2015-01-01

To our knowledge, this is the largest study evaluating relationships between 3T Magnetic Resonance Imaging (MRI) and P300 and memory/cognitive tests in the literature. The 3T MRI using NeuroQuant has an increased resolution 15 times that of 1.5T MRI. Utilizing NeuroQuant 3T MRI as a diagnostic tool in primary care, subjects (N=169; 19-90 years) displayed increased areas of anatomical atrophy: 34.62% hippocampal atrophy (N=54), 57.14% central atrophy (N=88), and 44.52% temporal atrophy (N=69). A majority of these patients exhibited overlap in measured areas of atrophy and were cognitively impaired. These results positively correlated with decreased P300 values and WMS-III (WMS-III) scores differentially across various brain loci. Delayed latency (p=0.0740) was marginally associated with temporal atrophy; reduced fractional anisotropy (FA) in frontal lobes correlated with aging, delayed P300 latency, and decreased visual and working memory (p=0.0115). Aging and delayed P300 latency correlated with lower FA. The correlation between working memory and reduced FA in frontal lobes is marginally significant (p=0.0787). In the centrum semiovale (CS), reduced FA correlated with visual memory (p=0.0622). Lower demyelination correlated with higher P300 amplitude (p=0.0002). Compared to males, females have higher demyelination (p=0.0064). Along these lines, the higher the P300 amplitude, the lower the bilateral atrophy (p=0.0165). Hippocampal atrophy correlated with increased auditory memory and gender, especially in males (p=0.0087). In considering temporal lobe atrophy correlations: delayed P300 latency and high temporal atrophy (p=0.0740); high auditory memory and low temporal atrophy (p=0.0417); and high working memory and low temporal atrophy (p=0.0166). Central atrophy correlated with aging and immediate memory (p=0.0294): the higher the immediate memory, the lower the central atrophy. Generally, the validation of brain atrophy by P300 and WMS-III could lead to cost-effective methods utilizable in primary care medicine following further confirmation.

Evoked Potentials and Memory/Cognition Tests Validate Brain Atrophy as Measured by 3T MRI (NeuroQuant) in Cognitively Impaired Patients

PubMed Central

Braverman, Eric R.; Blum, Kenneth; Hussman, Karl L.; Han, David; Dushaj, Kristina; Li, Mona; Marin, Gabriela; Badgaiyan, Rajendra D.; Smayda, Richard; Gold, Mark S.

2015-01-01

To our knowledge, this is the largest study evaluating relationships between 3T Magnetic Resonance Imaging (MRI) and P300 and memory/cognitive tests in the literature. The 3T MRI using NeuroQuant has an increased resolution 15 times that of 1.5T MRI. Utilizing NeuroQuant 3T MRI as a diagnostic tool in primary care, subjects (N=169; 19–90 years) displayed increased areas of anatomical atrophy: 34.62% hippocampal atrophy (N=54), 57.14% central atrophy (N=88), and 44.52% temporal atrophy (N=69). A majority of these patients exhibited overlap in measured areas of atrophy and were cognitively impaired. These results positively correlated with decreased P300 values and WMS-III (WMS-III) scores differentially across various brain loci. Delayed latency (p=0.0740) was marginally associated with temporal atrophy; reduced fractional anisotropy (FA) in frontal lobes correlated with aging, delayed P300 latency, and decreased visual and working memory (p=0.0115). Aging and delayed P300 latency correlated with lower FA. The correlation between working memory and reduced FA in frontal lobes is marginally significant (p=0.0787). In the centrum semiovale (CS), reduced FA correlated with visual memory (p=0.0622). Lower demyelination correlated with higher P300 amplitude (p=0.0002). Compared to males, females have higher demyelination (p=0.0064). Along these lines, the higher the P300 amplitude, the lower the bilateral atrophy (p=0.0165). Hippocampal atrophy correlated with increased auditory memory and gender, especially in males (p=0.0087). In considering temporal lobe atrophy correlations: delayed P300 latency and high temporal atrophy (p=0.0740); high auditory memory and low temporal atrophy (p=0.0417); and high working memory and low temporal atrophy (p=0.0166). Central atrophy correlated with aging and immediate memory (p=0.0294): the higher the immediate memory, the lower the central atrophy. Generally, the validation of brain atrophy by P300 and WMS-III could lead to cost-effective methods utilizable in primary care medicine following further confirmation. PMID:26244349

Studies of Implicit Prototype Extraction In Patients with Mild Cognitive Impairment and Early Alzheimer’s Disease

PubMed Central

Nosofsky, Robert M.; Denton, Stephen E.; Zaki, Safa R.; Murphy-Knudsen, Anne F.; Unverzagt, Frederick W.

2013-01-01

Studies of incidental category learning support the hypothesis of an implicit prototype-extraction system which is distinct from explicit memory (Smith, 2008). In those studies, patients with explicit-memory impairments due to damage to the medial-temporal lobe performed normally in implicit categorization tasks (Bozoki, Grossman, & Smith, 2006; Knowlton & Squire, 1993). However, alternative interpretations are that: i) even people with impairments to a single memory system have sufficient resources to succeed on the particular categorization tasks that have been tested (Nosofsky & Zaki, 1998; Zaki & Nosofsky, 2001); and ii) working memory can be used at time of test to learn the categories (Palmeri & Flanery, 1999). In the present experiments, patients with amnestic mild cognitive impairment or early Alzheimer’s disease were tested in prototype-extraction tasks to examine these possibilities. In a categorization task involving discrete-feature stimuli, the majority of subjects relied on memories for exceedingly few features, even when the task structure strongly encouraged reliance on broad-based prototypes. In a dot-pattern categorization task, even the memory-impaired patients were able to use working memory at time of test to extract the category structure (at least for the stimulus set used in past work). We argue that the results weaken the past case made in favor of a separate system of implicit-prototype extraction. PMID:22746953

Contributions of Volumetrics of the Hippocampus and Thalamus to Verbal Memory in Temporal Lobe Epilepsy Patients

ERIC Educational Resources Information Center

Stewart, Christopher C.; Griffith, H. Randall; Okonkwo, Ozioma C.; Martin, Roy C.; Knowlton, Robert K.; Richardson, Elizabeth J.; Hermann, Bruce P.; Seidenberg, Michael

2009-01-01

Recent theories have posited that the hippocampus and thalamus serve distinct, yet related, roles in episodic memory. Whereas the hippocampus has been implicated in long-term memory encoding and storage, the thalamus, as a whole, has been implicated in the selection of items for subsequent encoding and the use of retrieval strategies. However,…

Neuroimaging correlates of parent ratings of working memory in typically developing children

PubMed Central

Mahone, E. Mark; Martin, Rebecca; Kates, Wendy R.; Hay, Trisha; Horská, Alena

2009-01-01

The purpose of the present study was to investigate construct validity of parent ratings of working memory in children, using a multi-trait/multi-method design including neuroimaging, rating scales, and performance-based measures. Thirty-five typically developing children completed performance-based tests of working memory and nonexecutive function (EF) skills, received volumetric MRI, and were rated by parents on both EF-specific and broad behavior rating scales. After controlling for total cerebral volume and age, parent ratings of working memory were significantly correlated with frontal gray, but not temporal, parietal, or occipital gray, or any lobar white matter volumes. Performance-based measures of working memory were also moderately correlated with frontal lobe gray matter volume; however, non-EF parent ratings and non-EF performance-based measures were not correlated with frontal lobe volumes. Results provide preliminary support for the convergent and discriminant validity of parent ratings of working memory, and emphasize their utility in exploring brain–behavior relationships in children. Rating scales that directly examine EF skills may potentially have ecological validity, not only for “everyday” function, but also as correlates of brain volume. PMID:19128526

Contributions of Feature Binding During Encoding and Functional Connectivity of the Medial Temporal Lobe Structures to Episodic Memory Deficits Across the Prodromal and First-Episode Phases of Schizophrenia

PubMed Central

Haut, Kristen M.; van Erp, Theo G. M.; Knowlton, Barbara; Bearden, Carrie E.; Subotnik, Kenneth; Ventura, Joseph; Nuechterlein, Keith H.; Cannon, Tyrone D.

2014-01-01

Patients with and at risk for psychosis may have difficulty using associative strategies to facilitate episodic memory encoding and recall. In parallel studies, patients with first-episode schizophrenia (n = 27) and high psychosis risk (n = 28) compared with control participants (n = 22 and n = 20, respectively) underwent functional MRI during a remember-know memory task. Psychophysiological interaction analyses, using medial temporal lobe (MTL) structures as regions of interest, were conducted to measure functional connectivity patterns supporting successful episodic memory. During encoding, patients with first-episode schizophrenia demonstrated reduced functional coupling between MTL regions and regions involved in stimulus representations, stimulus selection, and cognitive control. Relative to control participants and patients with high psychosis risk who did not convert to psychosis, patients with high psychosis risk who later converted to psychosis also demonstrated reduced connectivity between MTL regions and auditory-verbal and visual-association regions. These results suggest that episodic memory deficits in schizophrenia are related to inefficient recruitment of cortical connections involved in associative memory formation; such deficits precede the onset of psychosis among those individuals at high clinical risk. PMID:25750836

Contributions of Feature Binding During Encoding and Functional Connectivity of the Medial Temporal Lobe Structures to Episodic Memory Deficits Across the Prodromal and First-Episode Phases of Schizophrenia.

PubMed

Haut, Kristen M; van Erp, Theo G M; Knowlton, Barbara; Bearden, Carrie E; Subotnik, Kenneth; Ventura, Joseph; Nuechterlein, Keith H; Cannon, Tyrone D

2015-03-01

Patients with and at risk for psychosis may have difficulty using associative strategies to facilitate episodic memory encoding and recall. In parallel studies, patients with first-episode schizophrenia ( n = 27) and high psychosis risk ( n = 28) compared with control participants ( n = 22 and n = 20, respectively) underwent functional MRI during a remember-know memory task. Psychophysiological interaction analyses, using medial temporal lobe (MTL) structures as regions of interest, were conducted to measure functional connectivity patterns supporting successful episodic memory. During encoding, patients with first-episode schizophrenia demonstrated reduced functional coupling between MTL regions and regions involved in stimulus representations, stimulus selection, and cognitive control. Relative to control participants and patients with high psychosis risk who did not convert to psychosis, patients with high psychosis risk who later converted to psychosis also demonstrated reduced connectivity between MTL regions and auditory-verbal and visual-association regions. These results suggest that episodic memory deficits in schizophrenia are related to inefficient recruitment of cortical connections involved in associative memory formation; such deficits precede the onset of psychosis among those individuals at high clinical risk.

Functional connectivity of hippocampal and prefrontal networks during episodic and spatial memory based on real-world environments.

PubMed

Robin, Jessica; Hirshhorn, Marnie; Rosenbaum, R Shayna; Winocur, Gordon; Moscovitch, Morris; Grady, Cheryl L

2015-01-01

Several recent studies have compared episodic and spatial memory in neuroimaging paradigms in order to understand better the contribution of the hippocampus to each of these tasks. In the present study, we build on previous findings showing common neural activation in default network areas during episodic and spatial memory tasks based on familiar, real-world environments (Hirshhorn et al. (2012) Neuropsychologia 50:3094-3106). Following previous demonstrations of the presence of functionally connected sub-networks within the default network, we performed seed-based functional connectivity analyses to determine how, depending on the task, the hippocampus and prefrontal cortex differentially couple with one another and with distinct whole-brain networks. We found evidence for a medial prefrontal-parietal network and a medial temporal lobe network, which were functionally connected to the prefrontal and hippocampal seeds, respectively, regardless of the nature of the memory task. However, these two networks were functionally connected with one another during the episodic memory task, but not during spatial memory tasks. Replicating previous reports of fractionation of the default network into stable sub-networks, this study also shows how these sub-networks may flexibly couple and uncouple with one another based on task demands. These findings support the hypothesis that episodic memory and spatial memory share a common medial temporal lobe-based neural substrate, with episodic memory recruiting additional prefrontal sub-networks. © 2014 Wiley Periodicals, Inc.

Everyday memory impairment in patients with temporal lobe epilepsy caused by hippocampal sclerosis.

PubMed

Rzezak, Patrícia; Lima, Ellen Marise; Gargaro, Ana Carolina; Coimbra, Erica; de Vincentiis, Silvia; Velasco, Tonicarlo Rodrigues; Leite, João Pereira; Busatto, Geraldo F; Valente, Kette D

2017-04-01

Patients with temporal lobe epilepsy caused by hippocampal sclerosis (TLE-HS) have episodic memory impairment. Memory has rarely been evaluated using an ecologic measure, even though performance on these tests is more related to patients' memory complaints. We aimed to measure everyday memory of patients with TLE-HS to age- and gender-matched controls. We evaluated 31 patients with TLE-HS and 34 healthy controls, without epilepsy and psychiatric disorders, using the Rivermead Behavioral Memory Test (RBMT), Visual Reproduction (WMS-III) and Logical Memory (WMS-III). We evaluated the impact of clinical variables such as the age of onset, epilepsy duration, AED use, history of status epilepticus, and seizure frequency on everyday memory. Statistical analyses were performed using MANCOVA with years of education as a confounding factor. Patients showed worse performance than controls on traditional memory tests and in the overall score of RBMT. Patients had more difficulties to recall names, a hidden belonging, to deliver a message, object recognition, to remember a story full of details, a previously presented short route, and in time and space orientation. Clinical epilepsy variables were not associated with RBMT performance. Memory span and working memory were correlated with worse performance on RBMT. Patients with TLE-HS demonstrated deficits in everyday memory functions. A standard neuropsychological battery, designed to assess episodic memory, would not evaluate these impairments. Impairment in recalling names, routes, stories, messages, and space/time disorientation can adversely impact social adaptation, and we must consider these ecologic measures with greater attention in the neuropsychological evaluation of patients with memory complaints. Copyright © 2017 Elsevier Inc. All rights reserved.

A cognitive chameleon: Lessons from a novel MAPT mutation case

PubMed Central

Liang, Yuying; Gordon, Elizabeth; Rohrer, Jonathan; Downey, Laura; de Silva, Rohan; Jäger, Hans Rolf; Nicholas, Jennifer; Modat, Marc; Cardoso, M. Jorge; Mahoney, Colin; Warren, Jason; Rossor, Martin; Fox, Nick; Caine, Diana

2014-01-01

We report a case of frontotemporal dementia caused by a novel MAPT mutation (Q351R) with a remarkably long amnestic presentation mimicking familial Alzheimer’s disease. Longitudinal clinical, neuropsychological and imaging data provide convergent evidence for predominantly bilateral anterior medial temporal lobe involvement consistent with previously established neuroanatomical signatures of MAPT mutations. This case supports the notion that the neural network affected in MAPT mutations is determined to a large extent by the underlying molecular pathology. We discuss the diagnostic significance of anomia in the context of atypical amnesia and the impact of impaired episodic and semantic memory systems on autobiographical memory. PMID:23998300

Hippocampal and prefrontal cortex contributions to learning and memory: analysis of lesion and aging effects on maze learning in rats.

PubMed

Winocur, G; Moscovitch, M

1990-08-01

Young adult rats with bilateral lesions to the hippocampus or prefrontal cortex, young operated controls, and normal old rats were tested on two complex mazes in the Hebb-Williams series. Approximately half the animals were previously trained on one of the mazes; the remainder received no previous training. The trained hippocampal rats showed sparing of memory for the general skill of maze learning but poor recall of the specific maze on which they had been previously trained. The opposite pattern was observed in trained prefrontal rats. In contrast, the aged rats' memory for maze-specific and maze-general information was impaired. The results confirmed the importance of the hippocampus for recalling highly specific information and pointed to a possible role for the frontal lobes in learning and remembering nonspecific skill-related information. The generalized deficit of the aged rats indicates that both types of memory were compromised and offers further evidence of frontal lobe and hippocampal dysfunction in normal aging.

Regional cerebral blood flow (rCBF) in schizophrenia during verbal memory activation: a 99mTc-HMPAO single photon emission tomography (SPET) study.

PubMed

Busatto, G F; Costa, D C; Ell, P J; Pilowsky, L S; David, A S; Kerwin, R W

1994-05-01

Regional cerebral blood flow (rCBF) was investigated in a group of medicated DSM-III-R schizophrenic patients and age, sex and handedness matched normal volunteers using a split-dose 99mTc-HMPAO Single Photon Emission Tomography (SPET) protocol. Measures were taken during the performance of a verbal memory task aimed at activating the left medial temporal lobe, a region repeatedly suggested to be structurally abnormal in schizophrenia. In normal subjects, the performance of the task was associated with significant rCBF increases in the left medial temporal, left inferior frontal and anterior cingulate cortices, and right cerebellum. Despite their significantly poorer performance on the memory task, the degree of medial temporal activation measured in the schizophrenic patients was not significantly different from that found in the control group. This finding suggests that memory deficits in schizophrenia do not necessarily imply failure to activate the left medial temporal lobe as assessed by 99mTc-HMPAO SPET.

Episodic memory in former professional football players with a history of concussion: an event-related functional neuroimaging study.

PubMed

Ford, Jaclyn H; Giovanello, Kelly S; Guskiewicz, Kevin M

2013-10-15

Previous research has demonstrated that sport-related concussions can have short-term effects on cognitive processes, but the long-term consequences are less understood and warrant more research. This study was the first to use event-related functional magnetic resonance imaging (fMRI) to examine long-term differences in neural activity during memory tasks in former athletes who have sustained multiple sport-related concussions. In an event-related fMRI study, former football players reporting multiple sport-related concussions (i.e., three or more) were compared with players who reported fewer than three concussions during a memory paradigm examining item memory (i.e., memory for the particular elements of an event) and relational memory (i.e., memory for the relationships between elements). Behaviorally, we observed that concussion history did not significantly affect behavioral performance, because persons in the low and high concussion groups had equivalent performance on both memory tasks, and in addition, that concussion history was not associated with any behavioral memory measures. Despite demonstrating equivalent behavioral performance, the two groups of former players demonstrated different neural recruitment patterns during relational memory retrieval, suggesting that multiple concussions may be associated with functional inefficiencies in the relational memory network. In addition, the number of previous concussions significantly correlated with functional activity in a number of brain regions, including the medial temporal lobe and inferior parietal lobe. Our results provide important insights in understanding the long-term functional consequences of sustaining multiple sports-related concussions.

Individual prediction of change in delayed recall of prose passages after left-sided anterior temporal lobectomy.

PubMed

Jokeit, H; Ebner, A; Holthausen, H; Markowitsch, H J; Moch, A; Pannek, H; Schulz, R; Tuxhorn, I

1997-08-01

Prognostic variables for individual memory outcome after left anterior temporal lobectomy (ATL) were studied in 27 patients with refractory temporal lobe epilepsy. The difference between pre- and postoperative performance in the delayed recall of two prose passages (Story A and B) from the Wechsler Memory Scale served as measure of postoperative memory change. Fifteen independent clinical, neuropsychological, and electrophysiological variables were submitted to a multiple linear regression analysis. Preoperative immediate and delayed recall of story content and right hemisphere Wada memory performance for pictorial and verbal items explained very well postoperative memory changes in recall of Story B. Delayed recall of Story B, but not of Story A, had high concurrent validity to other measures of memory. Patients who became seizure-free did not differ in memory change from patients who continued to have seizures after ATL. The variables age at epilepsy onset and probable age at temporal lobe damage provided complementary information for individual prediction but with less effectiveness than Wada test data. Our model confirmed that good preoperative memory functioning and impaired right hemispheric Wada memory performance for pictorial items predict a high risk of memory loss after left ATL. The analyses demonstrate that the combination of independent measures delivers more information than Wada test performance or any other variable alone. The suggested function can be used routinely to estimate the individual severity of verbal episodic memory impairment that might occur after left-sided ATL and offers a rational basis for the counseling of patients.

H.M. never again! An analysis of H.M.'s epilepsy and treatment.

PubMed

Mauguière, F; Corkin, S

2015-03-01

On August 25, 1953, the patient H.M., aged 27, underwent a bilateral surgical destruction of the inner aspect of his temporal lobes performed by William Beecher Scoville with the aim to control H.M.'s drug refractory epileptic seizures and alleviate their impact on his quality of life. Postoperatively, H.M. presented for 55 years a "striking and totally unexpected grave loss of recent memories". This paper reports what we know about H.M.'s epilepsy before and after surgery and puts forward arguments supporting the syndromic classification of his epilepsy. We attempted to elucidate what could have been the rationale, in 1953, of Scoville's decision to carry out a bilateral ablation of H.M.'s medial temporal lobe structures, and we examined whether there was any convincing argument published before 1953 suggesting that bilateral hippocampal ablation could result in a permanent and severe amnesia. Our a posteriori analysis of H.M.'s medical history suggested that he was most probably suffering from idiopathic generalized epilepsy with absences and generalized convulsive seizures worsened by high dosage phenytoin treatment, or less probably from cryptogenic frontal lobe epilepsy. Importantly, he did not have temporal lobe epilepsy. Scoville based his proposal of bilateral mesial temporal lobe ablation on his experience as a psychosurgeon and on the assumption that the threshold of generalized epileptic activity could be lowered by some kind of hippocampal dysfunction potentially epileptic in nature. Given the scanty information on the link between amnesia and medial temporal lobe lesions that was available in humans in 1953, one can understand why Scoville was so surprised by the "striking and totally unexpected" memory loss he observed in H.M. after the bilateral ablation of his mesial temporal lobe structures. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Semantics of the visual environment encoded in parahippocampal cortex

PubMed Central

Bonner, Michael F.; Price, Amy Rose; Peelle, Jonathan E.; Grossman, Murray

2016-01-01

Semantic representations capture the statistics of experience and store this information in memory. A fundamental component of this memory system is knowledge of the visual environment, including knowledge of objects and their associations. Visual semantic information underlies a range of behaviors, from perceptual categorization to cognitive processes such as language and reasoning. Here we examine the neuroanatomic system that encodes visual semantics. Across three experiments, we found converging evidence indicating that knowledge of verbally mediated visual concepts relies on information encoded in a region of the ventral-medial temporal lobe centered on parahippocampal cortex. In an fMRI study, this region was strongly engaged by the processing of concepts relying on visual knowledge but not by concepts relying on other sensory modalities. In a study of patients with the semantic variant of primary progressive aphasia (semantic dementia), atrophy that encompassed this region was associated with a specific impairment in verbally mediated visual semantic knowledge. Finally, in a structural study of healthy adults from the fMRI experiment, gray matter density in this region related to individual variability in the processing of visual concepts. The anatomic location of these findings aligns with recent work linking the ventral-medial temporal lobe with high-level visual representation, contextual associations, and reasoning through imagination. Together this work suggests a critical role for parahippocampal cortex in linking the visual environment with knowledge systems in the human brain. PMID:26679216

Semantics of the Visual Environment Encoded in Parahippocampal Cortex.

PubMed

Bonner, Michael F; Price, Amy Rose; Peelle, Jonathan E; Grossman, Murray

2016-03-01

Semantic representations capture the statistics of experience and store this information in memory. A fundamental component of this memory system is knowledge of the visual environment, including knowledge of objects and their associations. Visual semantic information underlies a range of behaviors, from perceptual categorization to cognitive processes such as language and reasoning. Here we examine the neuroanatomic system that encodes visual semantics. Across three experiments, we found converging evidence indicating that knowledge of verbally mediated visual concepts relies on information encoded in a region of the ventral-medial temporal lobe centered on parahippocampal cortex. In an fMRI study, this region was strongly engaged by the processing of concepts relying on visual knowledge but not by concepts relying on other sensory modalities. In a study of patients with the semantic variant of primary progressive aphasia (semantic dementia), atrophy that encompassed this region was associated with a specific impairment in verbally mediated visual semantic knowledge. Finally, in a structural study of healthy adults from the fMRI experiment, gray matter density in this region related to individual variability in the processing of visual concepts. The anatomic location of these findings aligns with recent work linking the ventral-medial temporal lobe with high-level visual representation, contextual associations, and reasoning through imagination. Together, this work suggests a critical role for parahippocampal cortex in linking the visual environment with knowledge systems in the human brain.

Autobiographical memory loss following a right prefrontal lobe tumour resection: a case report and review of the literature.

PubMed

Jamjoom, A A B; Gallo, P; Kandasamy, J; Phillips, J; Sokol, D

2017-07-01

The right prefrontal lobe has not traditionally been considered eloquent brain. Resection of tumours within this region does not typically lead to permanent functional impairment. In this report, we highlight the case of a patient who developed autobiographical memory loss following an uncomplicated resection of a right prefrontal tumour. A previously fit and well 15-year old presented with a persistent right-sided headache. An MRI demonstrated an expanded right mid-frontal gyrus with changes consistent with a low-grade tumour. The patient underwent a right-sided craniotomy and resection of the lesion which was confirmed as a WHO grade II diffuse astrocytoma. Postoperatively, the patient reported profound retrograde amnesia for a range of memory components, in particular autobiographical memory and semantic memory. Postoperative imaging showed a good resection margin with no evidence of underlying brain injury. Over an 18-month period, the patient showed no improvement in autobiographical memory; however, significant relearning of semantic knowledge took place and her academic performance was found to be in line with expectations for her age. In this report, we discuss a case and review the literature on the role of the right prefrontal cortex in memory and caution on the perception of right prefrontal non-eloquence.

Impact of emotional salience on episodic memory in attention-deficit/hyperactivity disorder: a functional magnetic resonance imaging study.

PubMed

Krauel, Kerstin; Duzel, Emrah; Hinrichs, Hermann; Santel, Stephanie; Rellum, Thomas; Baving, Lioba

2007-06-15

Patients with attention-deficit/hyperactivity disorder (ADHD) show episodic memory deficits especially in complex memory tasks. We investigated the neural correlates of memory formation in ADHD and their modulation by stimulus salience. We recorded event-related functional magnetic resonance imaging during an episodic memory paradigm with neutral and emotional pictures in 12 male ADHD subjects and 12 healthy adolescents. Emotional salience did significantly augment memory performance in ADHD patients. Successful encoding of neutral pictures was associated with activation of the anterior cingulate cortex (ACC) in healthy adolescents but with activation of the superior parietal lobe (SPL) and precuneus in ADHD patients. Successful encoding of emotional pictures was associated with prefrontal and inferior temporal cortex activation in both groups. Healthy adolescents, moreover, showed deactivation in the inferior parietal lobe. From a pathophysiological point of view, the most striking functional differences between healthy adolescents and ADHD patients were in the ACC and SPL. We suggest that increased SPL activation in ADHD reflected attentional compensation for low ACC activation during the encoding of neutral pictures. The higher salience of emotional stimuli, in contrast, regulated the interplay between ACC and SPL in conjunction with improving memory to the level of healthy adolescents.

A biased competition account of attention and memory in Alzheimer's disease

PubMed Central

Finke, Kathrin; Myers, Nicholas; Bublak, Peter; Sorg, Christian

2013-01-01

The common view of Alzheimer's disease (AD) is that of an age-related memory disorder, i.e. declarative memory deficits are the first signs of the disease and associated with progressive brain changes in the medial temporal lobes and the default mode network. However, two findings challenge this view. First, new model-based tools of attention research have revealed that impaired selective attention accompanies memory deficits from early pre-dementia AD stages on. Second, very early distributed lesions of lateral parietal networks may cause these attention deficits by disrupting brain mechanisms underlying attentional biased competition. We suggest that memory and attention impairments might indicate disturbances of a common underlying neurocognitive mechanism. We propose a unifying account of impaired neural interactions within and across brain networks involved in attention and memory inspired by the biased competition principle. We specify this account at two levels of analysis: at the computational level, the selective competition of representations during both perception and memory is biased by AD-induced lesions; at the large-scale brain level, integration within and across intrinsic brain networks, which overlap in parietal and temporal lobes, is disrupted. This account integrates a large amount of previously unrelated findings of changed behaviour and brain networks and favours a brain mechanism-centred view on AD. PMID:24018724

A biased competition account of attention and memory in Alzheimer's disease.

PubMed

Finke, Kathrin; Myers, Nicholas; Bublak, Peter; Sorg, Christian

2013-10-19

The common view of Alzheimer's disease (AD) is that of an age-related memory disorder, i.e. declarative memory deficits are the first signs of the disease and associated with progressive brain changes in the medial temporal lobes and the default mode network. However, two findings challenge this view. First, new model-based tools of attention research have revealed that impaired selective attention accompanies memory deficits from early pre-dementia AD stages on. Second, very early distributed lesions of lateral parietal networks may cause these attention deficits by disrupting brain mechanisms underlying attentional biased competition. We suggest that memory and attention impairments might indicate disturbances of a common underlying neurocognitive mechanism. We propose a unifying account of impaired neural interactions within and across brain networks involved in attention and memory inspired by the biased competition principle. We specify this account at two levels of analysis: at the computational level, the selective competition of representations during both perception and memory is biased by AD-induced lesions; at the large-scale brain level, integration within and across intrinsic brain networks, which overlap in parietal and temporal lobes, is disrupted. This account integrates a large amount of previously unrelated findings of changed behaviour and brain networks and favours a brain mechanism-centred view on AD.

Default mode network connectivity indicates episodic memory capacity in mesial temporal lobe epilepsy.

PubMed

McCormick, Cornelia; Quraan, Maher; Cohn, Melanie; Valiante, Taufik A; McAndrews, Mary Pat

2013-05-01

The clinical relevance of resting state functional connectivity in neurologic disorders, including mesial temporal lobe epilepsy (mTLE), remains unclear. This study investigated how connectivity in the default mode network changes with unilateral damage to one of its nodes, the hippocampus (HC), and how such connectivity can be exploited clinically to characterize memory deficits and indicate postsurgical memory change. Functional magnetic resonance imaging (fMRI) resting state scans and neuropsychological memory assessments (Warrington Recognition Tests for Words and Faces) were performed on 19 healthy controls, 20 patients with right mTLE, and 18 patients with left mTLE. In addition, postsurgical fMRI resting state and memory change (postsurgical memory performance-presurgical memory performance) data were available for half of these patients. Patients with mTLE showed reduced connectivity from the posterior cingulate cortex (PCC) to the epileptogenic HC and increased PCC connectivity to the contralateral HC. Stronger PCC connectivity to the epileptogenic HC was associated with better presurgical memory and with greater postsurgical memory decline. Stronger PCC connectivity to the contralateral HC was associated with less postsurgical memory decline. Following surgery, PCC connectivity to the remaining HC increased from presurgical values and showed enhanced correlation with postsurgical memory function. It is notable that this index was superior to others (hippocampal volume, preoperative memory scores) in explaining variance in memory change following surgery. Our results demonstrate the striking clinical significance of the brain's intrinsic connectivity in evaluating cognitive capacity and indicating the potential of postsurgical cognitive morbidity in patients with mTLE. Wiley Periodicals, Inc. © 2013 International League Against Epilepsy.

Naming and recognizing famous faces in temporal lobe epilepsy.

PubMed

Glosser, G; Salvucci, A E; Chiaravalloti, N D

2003-07-08

To assess naming and recognition of faces of familiar famous people in patients with epilepsy before and after anterior temporal lobectomy (ATL). Color photographs of famous people were presented for naming and description to 63 patients with temporal lobe epilepsy (TLE) either before or after ATL and to 10 healthy age- and education-matched controls. Spontaneous naming of photographed famous people was impaired in all patient groups, but was most abnormal in patients who had undergone left ATL. When allowed to demonstrate knowledge of the famous faces through verbal descriptions, rather than naming, patients with left TLE, left ATL, and right TLE improved to normal levels, but patients with right ATL were still impaired, suggesting a new deficit in identifying famous faces. Naming of famous people was related to naming of other common objects, verbal memory, and perceptual discrimination of faces. Recognition of the identity of pictured famous people was more related to visuospatial perception and memory. Lesions in anterior regions of the right temporal lobe impair recognition of the identities of familiar faces, as well as the learning of new faces. Lesions in the left temporal lobe, especially in anterior regions, disrupt access to the names of known people, but do not affect recognition of the identities of famous faces. Results are consistent with the hypothesized role of lateralized anterior temporal lobe structures in facial recognition and naming of unique entities.

Is "Learning" episodic memory? Distinct cognitive and neuroanatomic correlates of immediate recall during learning trials in neurologically normal aging and neurodegenerative cohorts.

PubMed

Casaletto, K B; Marx, G; Dutt, S; Neuhaus, J; Saloner, R; Kritikos, L; Miller, B; Kramer, J H

2017-07-28

Although commonly interpreted as a marker of episodic memory during neuropsychological exams, relatively little is known regarding the neurobehavior of "total learning" immediate recall scores. Medial temporal lobes are clearly associated with delayed recall performances, yet immediate recall may necessitate networks beyond traditional episodic memory. We aimed to operationalize cognitive and neuroanatomic correlates of total immediate recall in several aging syndromes. Demographically-matched neurologically normal adults (n=91), individuals with Alzheimer's disease (n=566), logopenic variant primary progressive aphasia (PPA) (n=34), behavioral variant frontotemporal dementia (n=97), semantic variant PPA (n=71), or nonfluent/agrammatic variant PPA (n=39) completed a neurocognitive battery, including the CVLT-Short Form trials 1-4 Total Immediate Recall; a majority subset also completed a brain MRI. Regressions covaried for age and sex, and MMSE in cognitive and total intracranial volume in neuroanatomic models. Neurologically normal adults demonstrated a heterogeneous pattern of cognitive associations with total immediate recall (executive, speed, delayed recall), such that no singular cognitive or neuroanatomic correlate uniquely predicted performance. Within the clinical cohorts, there were syndrome-specific cognitive and neural associations with total immediate recall; e.g., semantic processing was the strongest cognitive correlate in svPPA (partial r=0.41), while frontal volumes was the only meaningful neural correlate in bvFTD (partial r=0.20). Medial temporal lobes were not independently associated with total immediate recall in any group (ps>0.05). Multiple neurobehavioral systems are associated with "total learning" immediate recall scores that importantly differ across distinct clinical syndromes. Conventional memory networks may not be sufficient or even importantly contribute to total immediate recall in many syndromes. Interpreting learning scores as equivalent to episodic memory may be erroneous. Copyright © 2017 Elsevier Ltd. All rights reserved.

Visual working memory capacity and the medial temporal lobe.

PubMed

Jeneson, Annette; Wixted, John T; Hopkins, Ramona O; Squire, Larry R

2012-03-07

Patients with medial temporal lobe (MTL) damage are sometimes impaired at remembering visual information across delays as short as a few seconds. Such impairments could reflect either impaired visual working memory capacity or impaired long-term memory (because attention has been diverted or because working memory capacity has been exceeded). Using a standard change-detection task, we asked whether visual working memory capacity is intact or impaired after MTL damage. Five patients with hippocampal lesions and one patient with large MTL lesions saw an array of 1, 2, 3, 4, or 6 colored squares, followed after 3, 4, or 8 s by a second array where one of the colored squares was cued. The task was to decide whether the cued square had the same color as the corresponding square in the first array or a different color. At the 1 s delay typically used to assess working memory capacity, patients performed as well as controls at all array sizes. At the longer delays, patients performed as well as controls at small array sizes, thought to be within the capacity limit, and worse than controls at large array sizes, thought to exceed the capacity limit. The findings suggest that visual working memory capacity in humans is intact after damage to the MTL structures and that damage to these structures impairs performance only when visual working memory is insufficient to support performance.

Touching the void - First and third person perspectives in two cases of autobiographical amnesia linked to temporal lobe epilepsy.

PubMed

Zeman, Adam; Byruck, Marcus; Tallis, Peter; Vossel, Keith; Tranel, Daniel

2018-02-01

Temporal lobe epilepsy (TLE) can be associated with a marked impairment of autobiographical memory. This is occasionally its presenting feature. We describe two individuals with severe epilepsy-associated autobiographical memory loss. Both MB and PT were reassured initially that their memory was intact on the basis of standard neuropsychological tests. Both have written detailed accounts of their symptoms. The key neuropsychological features of their cases are the relative normality of performance on standard memory tests, with preservation of semantic memory for impersonal information, in contrast to a profound amnesia for salient autobiographical episodes and an impoverishment of imaginative scene construction. First person accounts from these individuals illustrate the importance of autobiographical memory in sustaining a coherent sense of self, informing interpersonal relationships and supporting future thinking and problem-solving. These cases contribute to the growing evidence for a distinctive pattern of autobiographical memory loss associated with TLE, and indicate that it can take a severe form affecting both personal semantics and episodic recollection. Defining the phase of memory processing most relevant to this form of amnesia, and the roles of physiological and structural pathology, requires further research. The paper's title refers to the introspective 'void' highlighted by both MB and PT in their reports - in PT's words: 'My primary symptom is the void that is my past'. Copyright © 2017. Published by Elsevier Ltd.

Does polycystic ovary syndrome affect cognition? A functional magnetic resonance imaging study exploring working memory.

PubMed

Soleman, Remi S; Kreukels, Baudewijntje P C; Veltman, Dick J; Cohen-Kettenis, Peggy T; Hompes, Peter G A; Drent, Madeleine L; Lambalk, Cornelis B

2016-05-01

To study effects of overexposure to androgens and subsequent antiandrogenic treatment on brain activity during working memory processes in women with polycystic ovary syndrome (PCOS). In this longitudinal study, working memory function was evaluated with the use of functional magnetic resonance imaging (MRI) in women with PCOS before and after antiandrogenic treatment. Department of reproductive medicine, university medical center. Fourteen women with PCOS and with hyperandrogenism and 20 healthy control women without any features of PCOS or other hormonal disorders. Antiandrogenic hormone treatment. Functional MRI response during a working memory task. At baseline women with PCOS showed more activation than the control group within the right superior parietal lobe and the inferior parietal lobe during task (all memory conditions). Task performance (speed and accuracy) did not differ between the groups. After antiandrogenic treatment the difference in overall brain activity between the groups disappeared and accuracy in the high memory load condition of the working memory task increased in women with PCOS. Women with PCOS may need additional neural resources during a working memory task compared with women without PCOS, suggesting less efficient executive functioning. This inefficiency may have effects on daily life functioning of women with PCOS. Antiandrogenic treatment appears to have a beneficial effect on this area of cognitive functioning. NTR2493. Copyright © 2016. Published by Elsevier Inc.

The role of the hippocampus in flexible cognition and social behavior

PubMed Central

Rubin, Rachael D.; Watson, Patrick D.; Duff, Melissa C.; Cohen, Neal J.

2014-01-01

Successful behavior requires actively acquiring and representing information about the environment and people, and manipulating and using those acquired representations flexibly to optimally act in and on the world. The frontal lobes have figured prominently in most accounts of flexible or goal-directed behavior, as evidenced by often-reported behavioral inflexibility in individuals with frontal lobe dysfunction. Here, we propose that the hippocampus also plays a critical role by forming and reconstructing relational memory representations that underlie flexible cognition and social behavior. There is mounting evidence that damage to the hippocampus can produce inflexible and maladaptive behavior when such behavior places high demands on the generation, recombination, and flexible use of information. This is seen in abilities as diverse as memory, navigation, exploration, imagination, creativity, decision-making, character judgments, establishing and maintaining social bonds, empathy, social discourse, and language use. Thus, the hippocampus, together with its extensive interconnections with other neural systems, supports the flexible use of information in general. Further, we suggest that this understanding has important clinical implications. Hippocampal abnormalities can produce profound deficits in real-world situations, which typically place high demands on the flexible use of information, but are not always obvious on diagnostic tools tuned to frontal lobe function. This review documents the role of the hippocampus in supporting flexible representations and aims to expand our understanding of the dynamic networks that operate as we move through and create meaning of our world. PMID:25324753

Towards an explicit account of implicit learning.

PubMed

Forkstam, Christian; Petersson, Karl Magnus

2005-08-01

The human brain supports acquisition mechanisms that can extract structural regularities implicitly from experience without the induction of an explicit model. Reber defined the process by which an individual comes to respond appropriately to the statistical structure of the input ensemble as implicit learning. He argued that the capacity to generalize to new input is based on the acquisition of abstract representations that reflect underlying structural regularities in the acquisition input. We focus this review of the implicit learning literature on studies published during 2004 and 2005. We will not review studies of repetition priming ('implicit memory'). Instead we focus on two commonly used experimental paradigms: the serial reaction time task and artificial grammar learning. Previous comprehensive reviews can be found in Seger's 1994 article and the Handbook of Implicit Learning. Emerging themes include the interaction between implicit and explicit processes, the role of the medial temporal lobe, developmental aspects of implicit learning, age-dependence, the role of sleep and consolidation. The attempts to characterize the interaction between implicit and explicit learning are promising although not well understood. The same can be said about the role of sleep and consolidation. Despite the fact that lesion studies have relatively consistently suggested that the medial temporal lobe memory system is not necessary for implicit learning, a number of functional magnetic resonance studies have reported medial temporal lobe activation in implicit learning. This issue merits further research. Finally, the clinical relevance of implicit learning remains to be determined.

The role of the hippocampus in flexible cognition and social behavior.

PubMed

Rubin, Rachael D; Watson, Patrick D; Duff, Melissa C; Cohen, Neal J

2014-01-01

Successful behavior requires actively acquiring and representing information about the environment and people, and manipulating and using those acquired representations flexibly to optimally act in and on the world. The frontal lobes have figured prominently in most accounts of flexible or goal-directed behavior, as evidenced by often-reported behavioral inflexibility in individuals with frontal lobe dysfunction. Here, we propose that the hippocampus also plays a critical role by forming and reconstructing relational memory representations that underlie flexible cognition and social behavior. There is mounting evidence that damage to the hippocampus can produce inflexible and maladaptive behavior when such behavior places high demands on the generation, recombination, and flexible use of information. This is seen in abilities as diverse as memory, navigation, exploration, imagination, creativity, decision-making, character judgments, establishing and maintaining social bonds, empathy, social discourse, and language use. Thus, the hippocampus, together with its extensive interconnections with other neural systems, supports the flexible use of information in general. Further, we suggest that this understanding has important clinical implications. Hippocampal abnormalities can produce profound deficits in real-world situations, which typically place high demands on the flexible use of information, but are not always obvious on diagnostic tools tuned to frontal lobe function. This review documents the role of the hippocampus in supporting flexible representations and aims to expand our understanding of the dynamic networks that operate as we move through and create meaning of our world.

Unique and shared validity of the "Wechsler logical memory test", the "California verbal learning test", and the "verbal learning and memory test" in patients with epilepsy.

PubMed

Helmstaedter, Christoph; Wietzke, Jennifer; Lutz, Martin T

2009-12-01

This study was set-up to evaluate the construct validity of three verbal memory tests in epilepsy patients. Sixty-one consecutively evaluated patients with temporal lobe epilepsy (TLE) or extra-temporal epilepsy (E-TLE) underwent testing with the verbal learning and memory test (VLMT, the German equivalent of the Rey auditory verbal learning test, RAVLT); the California verbal learning test (CVLT); the logical memory and digit span subtests of the Wechsler memory scale, revised (WMS-R); and testing of intelligence, attention, speech and executive functions. Factor analysis of the memory tests resulted in test-specific rather than test over-spanning factors. Parameters of the CVLT and WMS-R, and to a much lesser degree of the VLMT, were highly correlated with attention, language function and vocabulary. Delayed recall measures of logical memory and the VLMT differentiated TLE from E-TLE. Learning and memory scores off all three tests differentiated mesial temporal sclerosis from other pathologies. A lateralization of the epilepsy was possible only for a subsample of 15 patients with mesial TLE. Although the three tests provide overlapping indicators for a temporal lobe epilepsy or a mesial pathology, they can hardly be taken in exchange. The tests have different demands on semantic processing and memory organization, and they appear differentially sensitive to performance in non-memory domains. The tests capability to lateralize appears to be poor. The findings encourage the further discussion of the dependency of memory outcomes on test selection.

The influence of seizure frequency on anterograde and remote memory in mesial temporal lobe epilepsy.

PubMed

Voltzenlogel, Virginie; Vignal, Jean-Pierre; Hirsch, Edouard; Manning, Liliann

2014-10-01

Seizure frequency, although considered as an important factor in memory impairment in mesial temporal epilepsy (mTLE), is mostly confounded with other clinical variables, making it unclear to what extent recurrent seizures actually interfere with memory. The present study focuses on the influence of seizure frequency, studied as a main variable, on anterograde and remote memory. Seventy-one patients with unilateral mTLE were divided into two subgroups, as a function of their seizure frequency (monthly versus weekly seizures). Other seizure-related variables were controlled, namely, lateralisation and type of lesion, age at onset, years of ongoing seizures, etiologic factors, and number of AED. A comprehensive neuropsychological examination, including anterograde memory (verbal and non verbal recognition memory and free recall) tasks together with a large range of tests exploring different domains of remote memory, was carried out. Despite similar results on IQ, executive functions and attention, the low seizure-frequency group performed significantly better than the high seizure-frequency group on anterograde memory tests. Loss of autobiographical episodes and public-events memory, concomitant with spared personal semantic knowledge, was observed in both patient groups compared with healthy subjects. A worsening effect of high seizure frequency was recorded for autobiographical incidents and news-events memory, but unexpectedly, not for memory for famous people. The study of seizure frequency as the main variable leads us to suggest that high seizure frequency, itself, potentiates the effects of mesial temporal lobe damage on episodic memory deficits. Copyright © 2014 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

Methodological Aspects of Cognitive Rehabilitation with Eye Movement Desensitization and Reprocessing (EMDR)

PubMed Central

Zarghi, Afsaneh; Zali, Alireza; Tehranidost, Mehdi

2013-01-01

A variety of nervous system components such as medulla, pons, midbrain, cerebellum, basal ganglia, parietal, frontal and occipital lobes have role in Eye Movement Desensitization and Reprocessing (EMDR) processes. The eye movement is done simultaneously for attracting client's attention to an external stimulus while concentrating on a certain internal subject. Eye movement guided by therapist is the most common attention stimulus. The role of eye movement has been documented previously in relation with cognitive processing mechanisms. A series of systemic experiments have shown that the eyes’ spontaneous movement is associated with emotional and cognitive changes and results in decreased excitement, flexibility in attention, memory processing, and enhanced semantic recalling. Eye movement also decreases the memory's image clarity and the accompanying excitement. By using EMDR, we can reach some parts of memory which were inaccessible before and also emotionally intolerable. Various researches emphasize on the effectiveness of EMDR in treating and curing phobias, pains, and dependent personality disorders. Consequently, due to the involvement of multiple neural system components, this palliative method of treatment can also help to rehabilitate the neuro-cognitive system. PMID:25337334

Assessment of nonverbal learning and memory using the Design Learning Test.

PubMed

Foster, Paul S; Drago, Valeria; Harrison, David W

2009-05-01

The laterality of verbal and nonverbal learning and memory to the left and right temporal lobes, respectively, has received much empirical support. Researchers have often used the Rey Auditory Verbal Learning Test (RAVLT) as a measure of verbal learning and memory in these investigations. However, a precise analog of the RAVLT that uses stimuli difficult to encode verbally has not been reported. Further, although researchers have developed some measures that are essentially visuospatial analogs of the RAVLT, no correlational data have been reported attesting to the relation between the measures. The authors report the development of a nonverbal analog of the RAVLT, referred to as the Design Learning Test (DLT). Also, the authors present correlational data supporting a relation between the DLT and RAVLT, and they hope that the present study will stimulate research investigating whether the DLT is sensitive to right temporal lobe functioning.

Variability in the impairment of recognition memory in patients with frontal lobe lesions.

PubMed

Bastin, Christine; Van der Linden, Martial; Lekeu, Françoise; Andrés, Pilar; Salmon, Eric

2006-10-01

Fourteen patients with frontal lobe lesions and 14 normal subjects were tested on a recognition memory task that required discriminating between target words, new words that are synonyms of the targets and unrelated distractors. A deficit was found in 12 of the patients. Moreover, three different patterns of recognition impairment were identified: (I) poor memory for targets, (II) normal hits but increased false recognitions for both types of distractors, (III) normal hit rates, but increased false recognitions for synonyms only. Differences in terms of location of the damage and behavioral characteristics between these subgroups were examined. An encoding deficit was proposed to explain the performance of patients in subgroup I. The behavioral patterns of the patients in subgroups II and III could be interpreted as deficient post-retrieval verification processes and an inability to recollect item-specific information, respectively.

Recognition Memory for Words and Faces Before and After Temporal Lobectomy.

ERIC Educational Resources Information Center

Naugle, Richard I.; And Others

1994-01-01

To assess the sensitivity of Warrington's Recognition Memory Test "words" and "faces" subtests to lateralized temporal lobe seizure foci and effects of epilepsy surgery, 27 left- and 39 right-temporal lobectomy patients were tested before and after surgery. Conditions under which misclassification is most likely are discussed.…

Accelerated long-term forgetting in temporal lobe epilepsy: evidence of improvement after left temporal pole lobectomy.

PubMed

Gallassi, Roberto; Sambati, Luisa; Poda, Roberto; Stanzani Maserati, Michelangelo; Oppi, Federico; Giulioni, Marco; Tinuper, Paolo

2011-12-01

Accelerated long term forgetting (ALF) is a characteristic cognitive aspect in patients affected by temporal lobe epilepsy that is probably due to an impairment of memory consolidation and retrieval caused by epileptic activity in hippocampal and parahippocampal regions. We describe a case of a patient with TLE who showed improvement in ALF and in remote memory impairment after an anterior left temporal pole lobectomy including the uncus and amygdala. Our findings confirm that impairment of hippocampal functioning leads to pathological ALF, whereas restoration of hippocampal functioning brings ALF to a level comparable to that of controls. Copyright © 2011 Elsevier Inc. All rights reserved.

The role of the basal ganglia in learning and memory: insight from Parkinson's disease.

PubMed

Foerde, Karin; Shohamy, Daphna

2011-11-01

It has long been known that memory is not a single process. Rather, there are different kinds of memory that are supported by distinct neural systems. This idea stemmed from early findings of dissociable patterns of memory impairments in patients with selective damage to different brain regions. These studies highlighted the role of the basal ganglia in non-declarative memory, such as procedural or habit learning, contrasting it with the known role of the medial temporal lobes in declarative memory. In recent years, major advances across multiple areas of neuroscience have revealed an important role for the basal ganglia in motivation and decision making. These findings have led to new discoveries about the role of the basal ganglia in learning and highlighted the essential role of dopamine in specific forms of learning. Here we review these recent advances with an emphasis on novel discoveries from studies of learning in patients with Parkinson's disease. We discuss how these findings promote the development of current theories away from accounts that emphasize the verbalizability of the contents of memory and towards a focus on the specific computations carried out by distinct brain regions. Finally, we discuss new challenges that arise in the face of accumulating evidence for dynamic and interconnected memory systems that jointly contribute to learning. Copyright © 2011 Elsevier Inc. All rights reserved.

Intrusive Images in Psychological Disorders

PubMed Central

Brewin, Chris R.; Gregory, James D.; Lipton, Michelle; Burgess, Neil

2010-01-01

Involuntary images and visual memories are prominent in many types of psychopathology. Patients with posttraumatic stress disorder, other anxiety disorders, depression, eating disorders, and psychosis frequently report repeated visual intrusions corresponding to a small number of real or imaginary events, usually extremely vivid, detailed, and with highly distressing content. Both memory and imagery appear to rely on common networks involving medial prefrontal regions, posterior regions in the medial and lateral parietal cortices, the lateral temporal cortex, and the medial temporal lobe. Evidence from cognitive psychology and neuroscience implies distinct neural bases to abstract, flexible, contextualized representations (C-reps) and to inflexible, sensory-bound representations (S-reps). We revise our previous dual representation theory of posttraumatic stress disorder to place it within a neural systems model of healthy memory and imagery. The revised model is used to explain how the different types of distressing visual intrusions associated with clinical disorders arise, in terms of the need for correct interaction between the neural systems supporting S-reps and C-reps via visuospatial working memory. Finally, we discuss the treatment implications of the new model and relate it to existing forms of psychological therapy. PMID:20063969

Semantic congruence enhances memory of episodic associations: role of theta oscillations.

PubMed

Atienza, Mercedes; Crespo-Garcia, Maite; Cantero, Jose L

2011-01-01

Growing evidence suggests that theta oscillations play a crucial role in episodic encoding. The present study evaluates whether changes in electroencephalographic theta source dynamics mediate the positive influence of semantic congruence on incidental associative learning. Here we show that memory for episodic associations (face-location) is more accurate when studied under semantically congruent contexts. However, only participants showing RT priming effect in a conceptual priming test (priming group) also gave faster responses when recollecting source information of semantically congruent faces as compared with semantically incongruent faces. This improved episodic retrieval was positively correlated with increases in theta power during the study phase mainly in the bilateral parahippocampal gyrus, left superior temporal gyrus, and left lateral posterior parietal lobe. Reconstructed signals from the estimated sources showed higher theta power for congruent than incongruent faces and also for the priming than the nonpriming group. These results are in agreement with the attention to memory model. Besides directing top-down attention to goal-relevant semantic information during encoding, the dorsal parietal lobe may also be involved in redirecting attention to bottom-up-driven memories thanks to connections between the medial-temporal and the left ventral parietal lobe. The latter function can either facilitate or interfere with encoding of face-location associations depending on whether they are preceded by semantically congruent or incongruent contexts, respectively, because only in the former condition retrieved representations related to the cue and the face are both coherent with the person identity and are both associated with the same location.

Patterns of verbal learning and memory in children with intractable temporal lobe or frontal lobe epilepsy.

PubMed

Fuentes, Amanda; Smith, Mary Lou

2015-12-01

The objective of this study was to provide a better understanding of the verbal learning and memory (VLM) patterns that might differentiate children with frontal lobe epilepsy (FLE) from children with temporal lobe epilepsy (TLE) and to examine the impact of variables thought to influence outcomes (seizure laterality, age at seizure onset, age at assessment, epilepsy duration, number of antiepileptic drugs). Retrospective analyses were carried out for children with intractable unilateral TLE (n=100) and FLE (n=27) who completed standardized measures of VLM entailing lists of single words or lists of word pairs. Mean intelligent quotients and VLM scores on single words fell within the average range for both groups, whereas scores fell within the low average to borderline range on word pairs. No significant overall differences in VLM were found between the group with TLE and the group with FLE. Older age at assessment and older age at seizure onset were generally associated with better VLM in both groups but were related to better performance in a number of indices in the group with TLE and only fewer intrusions in the group with FLE. The VLM profiles of children with TLE and FLE are generally similar. Older age at assessment and older age at seizure onset have a favorable impact on both groups but are related to better encoding, retrieval, and monitoring processes for the group with TLE and improved memory monitoring (i.e., as indicated by fewer intrusions) in the group with FLE. Copyright © 2015 Elsevier Inc. All rights reserved.

Getting a Grip on Memory: Unilateral Hand Clenching Alters Episodic Recall

DTIC Science & Technology

2013-04-24

States of America Abstract Unilateral hand clenching increases neuronal activity in the frontal lobe of the contralateral hemisphere. Such hand clenching...Simple clenching of one versus the other hand increases the neuronal activity of the frontal lobe in the opposite (contralateral) hemisphere [1], [2...hemispheres are thought to be differentially involved in many functions, including language , emotion, spatial processing, and local/global informa

A Pencil Rescues Impaired Performance on a Visual Discrimination Task in Patients with Medial Temporal Lobe Lesions

ERIC Educational Resources Information Center

Knutson, Ashley R.; Hopkins, Ramona O.; Squire, Larry R.

2013-01-01

We tested proposals that medial temporal lobe (MTL) structures support not just memory but certain kinds of visual perception as well. Patients with hippocampal lesions or larger MTL lesions attempted to identify the unique object among twin pairs of objects that had a high degree of feature overlap. Patients were markedly impaired under the more…

Going beyond LTM in the MTL: A Synthesis of Neuropsychological and Neuroimaging Findings on the Role of the Medial Temporal Lobe in Memory and Perception

ERIC Educational Resources Information Center

Graham, Kim S.; Barense, Morgan D.; Lee, Andy C. H.

2010-01-01

Studies in rats and non-human primates suggest that medial temporal lobe (MTL) structures play a role in perceptual processing, with the hippocampus necessary for spatial discrimination, and the perirhinal cortex for object discrimination. Until recently, there was little convergent evidence for analogous functional specialisation in humans, or…

Comprehension of Concrete and Abstract Words in Patients with Selective Anterior Temporal Lobe Resection and in Patients with Selective Amygdalo-Hippocampectomy

ERIC Educational Resources Information Center

Loiselle, Magalie; Rouleau, Isabelle; Nguyen, Dang Khoa; Dubeau, Francois; Macoir, Joel; Whatmough, Christine; Lepore, Franco; Joubert, Sven

2012-01-01

The role of the anterior temporal lobe (ATL) in semantic memory is now firmly established. There is still controversy, however, regarding the specific role of this region in processing various types of concepts. There have been reports of patients suffering from semantic dementia (SD), a neurodegenerative condition in which the ATL is damaged…

Cognitive and functional correlates of accelerated long-term forgetting in temporal lobe epilepsy.

PubMed

Audrain, Samantha; McAndrews, Mary P

2018-03-30

While we know that hippocampal dysfunction is responsible for the memory deficits that patients with temporal lobe epilepsy exhibit at relatively short study-test delays, the role of this region in accelerated long-term forgetting (ALF) is not yet clear. In the present study, we probed the role of the hippocampus in ALF by directly comparing memory for associations to memory that could be supported by item recognition during a forced choice recognition task over delays ranging from 15-min to 72-h. We additionally examined resting-state functional connectivity between the hippocampus and cortical regions known to be involved in processing these types of stimuli, as well as the relationship between ALF and various clinical variables including structural abnormality in the hippocampus, lateralization of epileptic focus, presence of seizures across the retention period, and standardized composite memory scores. We found evidence of accelerated forgetting for item stimuli (but not associative stimuli) by 6 h post-learning, which became statistically reliable by 72-h. This finding suggests that unlike controls, patients were unable to utilize novelty to reject the incorrect object-scene pair. While none of the examined clinical variables were related to long-term forgetting, reduced resting-state functional connectivity between the affected anterior hippocampus and unaffected lateral temporal cortex predicted forgetting of item stimuli over the 72-h delay. Implications for the role of the hippocampus in accelerated long-term forgetting, and existing theories of systems consolidation in this context are discussed. Crown Copyright © 2018. Published by Elsevier Ltd. All rights reserved.

Dissociations in cognitive memory: the syndrome of developmental amnesia.

PubMed

Vargha-Khadem, F; Gadian, D G; Mishkin, M

2001-09-29

The dearth of studies on amnesia in children has led to the assumption that when damage to the medial temporal lobe system occurs early in life, the compensatory capacity of the immature brain rescues memory functions. An alternative view is that such damage so interferes with the development of learning and memory that it results not in selective cognitive impairments but in general mental retardation. Data will be presented to counter both of these arguments. Results obtained from a series of 11 amnesic patients with a history of hypoxic ischaemic damage sustained perinatally or during childhood indicate that regardless of age at onset of hippocampal pathology, there is a pronounced dissociation between episodic memory, which is severely impaired, and semantic memory, which is relatively preserved. A second dissociation is characterized by markedly impaired recall and relatively spared recognition leading to a distinction between recollection-based versus familiarity-based judgements. These findings are discussed in terms of the locus and extent of neuropathology associated with hypoxic ischaemic damage, the neural basis of 'remembering' versus 'knowing', and a hierarchical model of cognitive memory.

Episodic Memory in Former Professional Football Players with a History of Concussion: An Event-Related Functional Neuroimaging Study

PubMed Central

Giovanello, Kelly S.; Guskiewicz, Kevin M.

2013-01-01

Abstract Previous research has demonstrated that sport-related concussions can have short-term effects on cognitive processes, but the long-term consequences are less understood and warrant more research. This study was the first to use event-related functional magnetic resonance imaging (fMRI) to examine long-term differences in neural activity during memory tasks in former athletes who have sustained multiple sport-related concussions. In an event-related fMRI study, former football players reporting multiple sport-related concussions (i.e., three or more) were compared with players who reported fewer than three concussions during a memory paradigm examining item memory (i.e., memory for the particular elements of an event) and relational memory (i.e., memory for the relationships between elements). Behaviorally, we observed that concussion history did not significantly affect behavioral performance, because persons in the low and high concussion groups had equivalent performance on both memory tasks, and in addition, that concussion history was not associated with any behavioral memory measures. Despite demonstrating equivalent behavioral performance, the two groups of former players demonstrated different neural recruitment patterns during relational memory retrieval, suggesting that multiple concussions may be associated with functional inefficiencies in the relational memory network. In addition, the number of previous concussions significantly correlated with functional activity in a number of brain regions, including the medial temporal lobe and inferior parietal lobe. Our results provide important insights in understanding the long-term functional consequences of sustaining multiple sports-related concussions. PMID:23679098

Memory for fearful faces across development: specialization of amygdala nuclei and medial temporal lobe structures.

PubMed

Pinabiaux, Charlotte; Hertz-Pannier, Lucie; Chiron, Catherine; Rodrigo, Sébastian; Jambaqué, Isabelle; Noulhiane, Marion

2013-01-01

Enhanced memory for emotional faces is a significant component of adaptive social interactions, but little is known on its neural developmental correlates. We explored the role of amygdaloid complex (AC) and medial temporal lobe (MTL) in emotional memory recognition across development, by comparing fMRI activations of successful memory encoding of fearful and neutral faces in children (n = 12; 8-12 years) and adolescents (n = 12; 13-17 years). Memory for fearful faces was enhanced compared with neutral ones in adolescents, as opposed to children. In adolescents, activations associated with successful encoding of fearful faces were centered on baso-lateral AC nuclei, hippocampus, enthorhinal and parahippocampal cortices. In children, successful encoding of fearful faces relied on activations of centro-mesial AC nuclei, which was not accompanied by functional activation of MTL memory structures. Successful encoding of neutral faces depended on activations in anterior MTL region (hippocampal head and body) in adolescents, but more posterior ones (hippocampal tail and parahippocampal cortex) in children. In conclusion, two distinct functional specializations emerge from childhood to adolescence and result in the enhancement of memory for these particular stimuli: the specialization of baso-lateral AC nuclei, which is associated with the expertise in processing emotional facial expression, and which is intimately related to the specialization of MTL memory network. How the interplay between specialization of AC nuclei and of MTL memory structures is fundamental for the edification of social interactions remains to be elucidated.

Memory for fearful faces across development: specialization of amygdala nuclei and medial temporal lobe structures

PubMed Central

Pinabiaux, Charlotte; Hertz-Pannier, Lucie; Chiron, Catherine; Rodrigo, Sébastian; Jambaqué, Isabelle; Noulhiane, Marion

2013-01-01

Enhanced memory for emotional faces is a significant component of adaptive social interactions, but little is known on its neural developmental correlates. We explored the role of amygdaloid complex (AC) and medial temporal lobe (MTL) in emotional memory recognition across development, by comparing fMRI activations of successful memory encoding of fearful and neutral faces in children (n = 12; 8–12 years) and adolescents (n = 12; 13–17 years). Memory for fearful faces was enhanced compared with neutral ones in adolescents, as opposed to children. In adolescents, activations associated with successful encoding of fearful faces were centered on baso-lateral AC nuclei, hippocampus, enthorhinal and parahippocampal cortices. In children, successful encoding of fearful faces relied on activations of centro-mesial AC nuclei, which was not accompanied by functional activation of MTL memory structures. Successful encoding of neutral faces depended on activations in anterior MTL region (hippocampal head and body) in adolescents, but more posterior ones (hippocampal tail and parahippocampal cortex) in children. In conclusion, two distinct functional specializations emerge from childhood to adolescence and result in the enhancement of memory for these particular stimuli: the specialization of baso-lateral AC nuclei, which is associated with the expertise in processing emotional facial expression, and which is intimately related to the specialization of MTL memory network. How the interplay between specialization of AC nuclei and of MTL memory structures is fundamental for the edification of social interactions remains to be elucidated. PMID:24399958

Cholecystokinin from the entorhinal cortex enables neural plasticity in the auditory cortex

PubMed Central

Li, Xiao; Yu, Kai; Zhang, Zicong; Sun, Wenjian; Yang, Zhou; Feng, Jingyu; Chen, Xi; Liu, Chun-Hua; Wang, Haitao; Guo, Yi Ping; He, Jufang

2014-01-01

Patients with damage to the medial temporal lobe show deficits in forming new declarative memories but can still recall older memories, suggesting that the medial temporal lobe is necessary for encoding memories in the neocortex. Here, we found that cortical projection neurons in the perirhinal and entorhinal cortices were mostly immunopositive for cholecystokinin (CCK). Local infusion of CCK in the auditory cortex of anesthetized rats induced plastic changes that enabled cortical neurons to potentiate their responses or to start responding to an auditory stimulus that was paired with a tone that robustly triggered action potentials. CCK infusion also enabled auditory neurons to start responding to a light stimulus that was paired with a noise burst. In vivo intracellular recordings in the auditory cortex showed that synaptic strength was potentiated after two pairings of presynaptic and postsynaptic activity in the presence of CCK. Infusion of a CCKB antagonist in the auditory cortex prevented the formation of a visuo-auditory association in awake rats. Finally, activation of the entorhinal cortex potentiated neuronal responses in the auditory cortex, which was suppressed by infusion of a CCKB antagonist. Together, these findings suggest that the medial temporal lobe influences neocortical plasticity via CCK-positive cortical projection neurons in the entorhinal cortex. PMID:24343575

Decoding the Formation of New Semantics: MVPA Investigation of Rapid Neocortical Plasticity during Associative Encoding through Fast Mapping.

PubMed

Atir-Sharon, Tali; Gilboa, Asaf; Hazan, Hananel; Koilis, Ester; Manevitz, Larry M

2015-01-01

Neocortical structures typically only support slow acquisition of declarative memory; however, learning through fast mapping may facilitate rapid learning-induced cortical plasticity and hippocampal-independent integration of novel associations into existing semantic networks. During fast mapping the meaning of new words and concepts is inferred, and durable novel associations are incidentally formed, a process thought to support early childhood's exuberant learning. The anterior temporal lobe, a cortical semantic memory hub, may critically support such learning. We investigated encoding of semantic associations through fast mapping using fMRI and multivoxel pattern analysis. Subsequent memory performance following fast mapping was more efficiently predicted using anterior temporal lobe than hippocampal voxels, while standard explicit encoding was best predicted by hippocampal activity. Searchlight algorithms revealed additional activity patterns that predicted successful fast mapping semantic learning located in lateral occipitotemporal and parietotemporal neocortex and ventrolateral prefrontal cortex. By contrast, successful explicit encoding could be classified by activity in medial and dorsolateral prefrontal and parahippocampal cortices. We propose that fast mapping promotes incidental rapid integration of new associations into existing neocortical semantic networks by activating related, nonoverlapping conceptual knowledge. In healthy adults, this is better captured by unique anterior and lateral temporal lobe activity patterns, while hippocampal involvement is less predictive of this kind of learning.

Counterfactual thinking: an fMRI study on changing the past for a better future

PubMed Central

Ma, Ning; Ampe, Lisa; Baetens, Kris; Van Overwalle, Frank

2013-01-01

Recent studies suggest that a brain network mainly associated with episodic memory has a more general function in imagining oneself in another time, place or perspective (e.g. episodic future thought, theory of mind, default mode). If this is true, counterfactual thinking (e.g. ‘If I had left the office earlier, I wouldn’t have missed my train.’) should also activate this network. Present functional magnetic resonance imaging (fMRI) study explores the common and distinct neural activity of counterfactual and episodic thinking by directly comparing the imagining of upward counterfactuals (creating better outcomes for negative past events) with the re-experiencing of negative past events and the imagining of positive future events. Results confirm that episodic and counterfactual thinking share a common brain network, involving a core memory network (hippocampal area, temporal lobes, midline, and lateral parietal lobes) and prefrontal areas that might be related to mentalizing (medial prefrontal cortex) and performance monitoring (right prefrontal cortex). In contrast to episodic past and future thinking, counterfactual thinking recruits some of these areas more strongly and extensively, and additionally activates the bilateral inferior parietal lobe and posterior medial frontal cortex. We discuss these findings in view of recent fMRI evidence on the working of episodic memory and theory of mind. PMID:22403155

When Do Objects Become Landmarks? A VR Study of the Effect of Task Relevance on Spatial Memory

PubMed Central

Han, Xue; Byrne, Patrick; Kahana, Michael; Becker, Suzanna

2012-01-01

We investigated how objects come to serve as landmarks in spatial memory, and more specifically how they form part of an allocentric cognitive map. Participants performing a virtual driving task incidentally learned the layout of a virtual town and locations of objects in that town. They were subsequently tested on their spatial and recognition memory for the objects. To assess whether the objects were encoded allocentrically we examined pointing consistency across tested viewpoints. In three experiments, we found that spatial memory for objects at navigationally relevant locations was more consistent across tested viewpoints, particularly when participants had more limited experience of the environment. When participants’ attention was focused on the appearance of objects, the navigational relevance effect was eliminated, whereas when their attention was focused on objects’ locations, this effect was enhanced, supporting the hypothesis that when objects are processed in the service of navigation, rather than merely being viewed as objects, they engage qualitatively distinct attentional systems and are incorporated into an allocentric spatial representation. The results are consistent with evidence from the neuroimaging literature that when objects are relevant to navigation, they not only engage the ventral “object processing stream”, but also the dorsal stream and medial temporal lobe memory system classically associated with allocentric spatial memory. PMID:22586455

Brain activity associated with memory and cognitive function during jaw-tapping movement in healthy subjects using functional magnetic resonance imaging.

PubMed

Cho, Seung-Yeon; Shin, Ae-Sook; Na, Byung-Jo; Jahng, Geon-Ho; Park, Seong-Uk; Jung, Woo-Sang; Moon, Sang-Kwan; Park, Jung-Mi

2013-06-01

To determine whether jaw-tapping movement, a classically described as an indication of personal well-being and mental health, stimulates the memory and the cognitive regions of the brain and is associated with improved brain performance. Twelve healthy right-handed female subjects completed the study. Each patient performed a jaw-tapping task and an n-back task during functional magnetic resonance imaging (fMRI). The subjects were trained to carry out the jaw-tapping movement at home twice a day for 4 weeks. The fMRI was repeated when they returned. During the first and second jaw-tapping session, both sides of precentral gyrus and the right middle frontal gyrus (BA 6) were activated. And during the second session of the jaw-tapping task, parts of frontal lobe and temporal lobe related to memory function were more activated. In addition, the total percent task accuracy in n-back task significantly increased after 4 weeks of jawtapping movement. After jaw-tapping training for 4 weeks, brain areas related to memory showed significantly increased blood oxygen level dependent signals. Jaw-tapping movement might be a useful exercise for stimulating the memory and cognitive regions of the brain.

Weak reward source memory in depression reflects blunted activation of VTA/SN and parahippocampus

PubMed Central

Dobbins, Ian G.; Pizzagalli, Diego A.

2014-01-01

Reward responses in the medial temporal lobes and dopaminergic midbrain boost episodic memory formation in healthy adults, and weak memory for emotionally positive material in depression suggests this mechanism may be dysfunctional in major depressive disorder (MDD). To test this hypothesis, we performed a study in which unmedicated adults with MDD and healthy controls encoded drawings paired with reward or zero tokens during functional magnetic resonance imaging. In a recognition test, participants judged whether drawings were previously associated with the reward token (‘reward source’) or the zero token (‘zero source’). Unlike controls, depressed participants failed to show better memory for drawings from the reward source vs the zero source. Consistent with predictions, controls also showed a stronger encoding response to reward tokens vs zero tokens in the right parahippocampus and dopaminergic midbrain, whereas the MDD group showed the opposite pattern—stronger responses to zero vs reward tokens—in these regions. Differential activation of the dopaminergic midbrain by reward vs zero tokens was positively correlated with the reward source memory advantage in controls, but not depressed participants. These data suggest that weaker memory for positive material in depression reflects blunted encoding responses in the dopaminergic midbrain and medial temporal lobes. PMID:24078019

Repetition Suppression and Reactivation in Auditory–Verbal Short-Term Recognition Memory

PubMed Central

D'Esposito, Mark

2009-01-01

The neural response to stimulus repetition is not uniform across brain regions, stimulus modalities, or task contexts. For instance, it has been observed in many functional magnetic resonance imaging (fMRI) studies that sometimes stimulus repetition leads to a relative reduction in neural activity (repetition suppression), whereas in other cases repetition results in a relative increase in activity (repetition enhancement). In the present study, we hypothesized that in the context of a verbal short-term recognition memory task, repetition-related “increases” should be observed in the same posterior temporal regions that have been previously associated with “persistent activity” in working memory rehearsal paradigms. We used fMRI and a continuous recognition memory paradigm with short lags to examine repetition effects in the posterior and anterior regions of the superior temporal cortex. Results showed that, consistent with our hypothesis, the 2 posterior temporal regions consistently associated with working memory maintenance, also show repetition increases during short-term recognition memory. In contrast, a region in the anterior superior temporal lobe showed repetition suppression effects, consistent with previous research work on perceptual adaptation in the auditory–verbal domain. We interpret these results in light of recent theories of the functional specialization along the anterior and posterior axes of the superior temporal lobe. PMID:18987393

Repetition suppression and reactivation in auditory-verbal short-term recognition memory.

PubMed

Buchsbaum, Bradley R; D'Esposito, Mark

2009-06-01

The neural response to stimulus repetition is not uniform across brain regions, stimulus modalities, or task contexts. For instance, it has been observed in many functional magnetic resonance imaging (fMRI) studies that sometimes stimulus repetition leads to a relative reduction in neural activity (repetition suppression), whereas in other cases repetition results in a relative increase in activity (repetition enhancement). In the present study, we hypothesized that in the context of a verbal short-term recognition memory task, repetition-related "increases" should be observed in the same posterior temporal regions that have been previously associated with "persistent activity" in working memory rehearsal paradigms. We used fMRI and a continuous recognition memory paradigm with short lags to examine repetition effects in the posterior and anterior regions of the superior temporal cortex. Results showed that, consistent with our hypothesis, the 2 posterior temporal regions consistently associated with working memory maintenance, also show repetition increases during short-term recognition memory. In contrast, a region in the anterior superior temporal lobe showed repetition suppression effects, consistent with previous research work on perceptual adaptation in the auditory-verbal domain. We interpret these results in light of recent theories of the functional specialization along the anterior and posterior axes of the superior temporal lobe.

Superior episodic memory in inconsistent-handers: a replication and extension using fNIRS.

PubMed

Propper, Ruth E; Patel, Neil; Christman, Stephen D; Carlei, Christophe

2017-11-01

A large body of evidence supports the existence of a robust handedness difference in episodic memory retrieval, with inconsistent-handedness being associated with superior memory across a wide variety of paradigms, including superior retrieval of lab-based and real world memories. Despite superior episidoc memory in inconsistent-handers, and despite neuroanatomical and neurophysiological differences in cortical regions between inconsistent- and consistent-handers, we are aware of no studies to date that have examined physiological activity in the brains of inconsistent- versus consistent-handers while engaged in memory tasks. The purpose of this paper, therefore, is to present a first look at this issue, using functional near-infrared spectroscopy (fNIRS) as a simple, non-invasive measure of frontal lobe activity during encoding and recall of list words in inconsistent- and consistent-handers. Behaviourally, we replicated prior studies, finding a significant inconsistent-handed advantage in free recall. Using fNIRS-derived oxygenated haemoglobin (O 2 Hb) as a measure of frontal lobe activity, we found the first evidence for handedness differences in brain activity that are associated with the handedness differences in episodic retrieval. Specifically, the primary finding was that increased O 2 Hb in the right hemisphere during recall was associated with better retrieval, but for consistent-handers only.

Hippocampus and Retrograde Amnesia in the Rat Model: A Modest Proposal for the Situation of Systems Consolidation

PubMed Central

Sutherland, Robert J.; Sparks, Fraser; Lehmann, Hugo

2010-01-01

The properties of retrograde amnesia after damage to the hippocampus have been explicated with some success using a rat model of human medial temporal lobe amnesia. We review the results of this experimental work with rats focusing on several areas of consensus in this growing literature. We evaluate the theoretically significant hypothesis that hippocampal retrograde amnesia normally exhibits a temporal gradient, affecting recent, but sparing remote memories. Surprisingly, the evidence does not provide much support for the idea that there is a lengthy process of systems consolidation following a learning episode. Instead, recent and remote memories tend to be equally affected. The extent of damage to the hippocampus is a significant factor in this work since it is likely that spared hippocampal tissue can support at least partial memory retrieval. With extensive hippocampal damage gradients are flat or, in the case of memory tasks with flavour/odour retrieval cues, the retrograde amnesia covers a period of about 1 – 3 days. There is consistent evidence that at the time of learning the hippocampus interferes with or overshadows memory acquisition by other systems. This contributes to the breadth and severity of retrograde amnesia relative to anterograde amnesia in the rat. The fact that multiple, distributed learning episodes can overcome this overshadowing is consistent with a parallel dual-store theory or a Distributed Reinstatement Theory in which each learning episode triggers a short period of memory replay that provides a brief hippocampal-dependent systems consolidation. PMID:20430043

Verbal and non-verbal semantic impairment: From fluent primary progressive aphasia to semantic dementia

PubMed Central

Senaha, Mirna Lie Hosogi; Caramelli, Paulo; Porto, Claudia Sellitto; Nitrini, Ricardo

2007-01-01

Selective disturbances of semantic memory have attracted the interest of many investigators and the question of the existence of single or multiple semantic systems remains a very controversial theme in the literature. Objectives To discuss the question of multiple semantic systems based on a longitudinal study of a patient who presented semantic dementia from fluent primary progressive aphasia. Methods A 66 year-old woman with selective impairment of semantic memory was examined on two occasions, undergoing neuropsychological and language evaluations, the results of which were compared to those of three paired control individuals. Results In the first evaluation, physical examination was normal and the score on the Mini-Mental State Examination was 26. Language evaluation revealed fluent speech, anomia, disturbance in word comprehension, preservation of the syntactic and phonological aspects of the language, besides surface dyslexia and dysgraphia. Autobiographical and episodic memories were relatively preserved. In semantic memory tests, the following dissociation was found: disturbance of verbal semantic memory with preservation of non-verbal semantic memory. Magnetic resonance of the brain revealed marked atrophy of the left anterior temporal lobe. After 14 months, the difficulties in verbal semantic memory had become more severe and the semantic disturbance, limited initially to the linguistic sphere, had worsened to involve non-verbal domains. Conclusions Given the dissociation found in the first examination, we believe there is sufficient clinical evidence to refute the existence of a unitary semantic system. PMID:29213389

Verbal memory and verbal fluency tasks used for language localization and lateralization during magnetoencephalography.

PubMed

Pirmoradi, Mona; Jemel, Boutheina; Gallagher, Anne; Tremblay, Julie; D'Hondt, Fabien; Nguyen, Dang Khoa; Béland, Renée; Lassonde, Maryse

2016-01-01

The aim of this study was to develop a presurgical magnetoencephalography (MEG) protocol to localize and lateralize expressive and receptive language function as well as verbal memory in patients with epilepsy. Two simple language tasks and a different analytical procedure were developed. Ten healthy participants and 13 epileptic patients completed two language tasks during MEG recording: a verbal memory task and a verbal fluency task. As a first step, principal component analyses (PCA) were performed on source data from the group of healthy participants to identify spatiotemporal factors that were relevant to these paradigms. Averaged source data were used to localize areas activated during each task and a laterality index (LI) was computed on an individual basis for both groups, healthy participants and patients, using sensor data. PCA revealed activation in the left temporal lobe (300 ms) during the verbal memory task, and from the frontal lobe (210 ms) to the temporal lobe (500 ms) during the verbal fluency task in healthy participants. Averaged source data showed activity in the left hemisphere (250-750 ms), in Wernicke's area, for all participants. Left hemisphere dominance was demonstrated better using the verbal memory task than the verbal fluency task (F1,19=4.41, p=0.049). Cohen's kappa statistic revealed 93% agreement (k=0.67, p=0.002) between LIs obtained from MEG sensor data and fMRI, the IAT, electrical cortical stimulation or handedness with the verbal memory task for all participants. At 74%, agreement results for the verbal fluency task did not reach statistical significance. Analysis procedures yielded interesting findings with both tasks and localized language-related activation. However, based on source localization and laterality indices, the verbal memory task yielded better results in the context of the presurgical evaluation of epileptic patients. The verbal fluency task did not add any further information to the verbal memory task as regards language localization and lateralization for most patients and healthy participants that would facilitate decision making prior to surgery. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Visuo-spatial memory deficits following medial temporal lobe damage: A comparison of three patient groups.

PubMed

Esfahani-Bayerl, Nazli; Finke, Carsten; Braun, Mischa; Düzel, Emrah; Heekeren, Hauke R; Holtkamp, Martin; Hasper, Dietrich; Storm, Christian; Ploner, Christoph J

2016-01-29

The contributions of the hippocampal formation and adjacent regions of the medial temporal lobe (MTL) to memory are still a matter of debate. It is currently unclear, to what extent discrepancies between previous human lesion studies may have been caused by the choice of distinct patient models of MTL dysfunction, as disorders affecting this region differ in selectivity, laterality and mechanisms of post-lesional compensation. Here, we investigated the performance of three distinct patient groups with lesions to the MTL with a battery of visuo-spatial short-term memory tasks. Thirty-one subjects with either unilateral damage to the MTL (postsurgical lesions following resection of a benign brain tumor, 6 right-sided lesions, 5 left) or bilateral damage (10 post-encephalitic lesions, 10 post-anoxic lesions) performed a series of tasks requiring short-term memory of colors, locations or color-location associations. We have shown previously that performance in the association task critically depends on hippocampal integrity. Patients with postsurgical damage of the MTL showed deficient performance in the association task, but performed normally in color and location tasks. Patients with left-sided lesions were almost as impaired as patients with right-sided lesions. Patients with bilateral post-encephalitic lesions showed comparable damage to MTL sub-regions and performed similarly to patients with postsurgical lesions in the association task. However, post-encephalitic patients showed additional impairments in the non-associative color and location tasks. A strikingly similar pattern of deficits was observed in post-anoxic patients. These results suggest a distinct cerebral organization of associative and non-associative short-term memory that was differentially affected in the three patient groups. Thus, while all patient groups may provide appropriate models of medial temporal lobe dysfunction in associative visuo-spatial short-term memory, additional deficits in non-associative memory tasks likely reflect damage of regions outside the MTL. Importantly, the choice of a patient model in human lesion studies of the MTL significantly influences overall performance patterns in visuo-spatial memory tasks. Copyright © 2015 Elsevier Ltd. All rights reserved.

Similar patterns of neural activity predict memory function during encoding and retrieval.

PubMed

Kragel, James E; Ezzyat, Youssef; Sperling, Michael R; Gorniak, Richard; Worrell, Gregory A; Berry, Brent M; Inman, Cory; Lin, Jui-Jui; Davis, Kathryn A; Das, Sandhitsu R; Stein, Joel M; Jobst, Barbara C; Zaghloul, Kareem A; Sheth, Sameer A; Rizzuto, Daniel S; Kahana, Michael J

2017-07-15

Neural networks that span the medial temporal lobe (MTL), prefrontal cortex, and posterior cortical regions are essential to episodic memory function in humans. Encoding and retrieval are supported by the engagement of both distinct neural pathways across the cortex and common structures within the medial temporal lobes. However, the degree to which memory performance can be determined by neural processing that is common to encoding and retrieval remains to be determined. To identify neural signatures of successful memory function, we administered a delayed free-recall task to 187 neurosurgical patients implanted with subdural or intraparenchymal depth electrodes. We developed multivariate classifiers to identify patterns of spectral power across the brain that independently predicted successful episodic encoding and retrieval. During encoding and retrieval, patterns of increased high frequency activity in prefrontal, MTL, and inferior parietal cortices, accompanied by widespread decreases in low frequency power across the brain predicted successful memory function. Using a cross-decoding approach, we demonstrate the ability to predict memory function across distinct phases of the free-recall task. Furthermore, we demonstrate that classifiers that combine information from both encoding and retrieval states can outperform task-independent models. These findings suggest that the engagement of a core memory network during either encoding or retrieval shapes the ability to remember the past, despite distinct neural interactions that facilitate encoding and retrieval. Copyright © 2017 Elsevier Inc. All rights reserved.

The effect of Vitamin E on learning and memory deficits in intrahippocampal kainate-induced temporal lobe epilepsy in rats.

PubMed

Kiasalari, Zahra; Khalili, Mohsen; Shafiee, Samaneh; Roghani, Mehrdad

2016-01-01

Since temporal lobe epilepsy (TLE) is associated with learning and memory impairment, we investigated the beneficial effect of Vitamin E on the impaired learning and memory in the intrahippocampal kainate model of TLE in rats. Rats were divided into sham, Vitamin E-treated sham, kainate, and Vitamin E-treated kainate. Intrahippocampal kainate was used for induction of epilepsy. Vitamin E was injected intraperitoneal (i.p.) at a dose of 200 mg/kg/day started 1 week before surgery until 1 h presurgery. Initial and step-through latencies in the passive avoidance test and alternation behavior percentage in Y-maze were finally determined in addition to measurement of some oxidative stress markers. Kainate injection caused a higher severity and rate of seizures and deteriorated learning and memory performance in passive avoidance paradigm and spontaneous alternation as an index of spatial recognition memory in Y-maze task. Intrahippocampal kainate also led to the elevation of malondialdehyde (MDA) and nitrite and reduced activity of superoxide dismutase (SOD). Vitamin E pretreatment significantly attenuated severity and incidence rate of seizures, significantly improved retrieval and recall in passive avoidance, did not ameliorate spatial memory deficit in Y-maze, and lowered MDA and enhanced SOD activity. Vitamin E improves passive avoidance learning and memory and part of its beneficial effect is due to its potential to mitigate hippocampal oxidative stress.

The Hippocampus Supports Encoding of Between-Domain Associations within Working Memory

ERIC Educational Resources Information Center

Piekema, Carinne; Kessel, Roy P. C.; Rijpkema, Mark; Fernandez, Guillen

2009-01-01

It has been established that the medial temporal lobe, including the hippocampus, is crucial for associative memory. The aim of the current functional magnetic resonance imaging (fMRI) study was to investigate whether the hippocampus is differentially activated for associations between items processed in the same neocortical region (within-domain)…

Working memory deficits in high-functioning adolescents with autism spectrum disorders: neuropsychological and neuroimaging correlates.

PubMed

Barendse, Evelien M; Hendriks, Marc Ph; Jansen, Jacobus Fa; Backes, Walter H; Hofman, Paul Am; Thoonen, Geert; Kessels, Roy Pc; Aldenkamp, Albert P

2013-06-04

Working memory is a temporary storage system under attentional control. It is believed to play a central role in online processing of complex cognitive information and may also play a role in social cognition and interpersonal interactions. Adolescents with a disorder on the autism spectrum display problems in precisely these domains. Social impairments, communication difficulties, and repetitive interests and activities are core domains of autism spectrum disorders (ASD), and executive function problems are often seen throughout the spectrum. As the main cognitive theories of ASD, including the theory of mind deficit hypotheses, weak central coherence account, and the executive dysfunction theory, still fail to explain the broad spectrum of symptoms, a new perspective on the etiology of ASD is needed. Deficits in working memory are central to many theories of psychopathology, and are generally linked to frontal-lobe dysfunction. This article will review neuropsychological and (functional) brain imaging studies on working memory in adolescents with ASD. Although still disputed, it is concluded that within the working memory system specific problems of spatial working memory are often seen in adolescents with ASD. These problems increase when information is more complex and greater demands on working memory are made. Neuroimaging studies indicate a more global working memory processing or connectivity deficiency, rather than a focused deficit in the prefrontal cortex. More research is needed to relate these working memory difficulties and neuroimaging results in ASD to the behavioral difficulties as seen in individuals with a disorder on the autism spectrum.

[Anterograde declarative memory and its models].

PubMed

Barbeau, E-J; Puel, M; Pariente, J

2010-01-01

Patient H.M.'s recent death provides the opportunity to highlight the importance of his contribution to a better understanding of the anterograde amnesic syndrome. The thorough study of this patient over five decades largely contributed to shape the unitary model of declarative memory. This model holds that declarative memory is a single system that cannot be fractionated into subcomponents. As a system, it depends mainly on medial temporal lobes structures. The objective of this review is to present the main characteristics of different modular models that have been proposed as alternatives to the unitary model. It is also an opportunity to present different patients, who, although less famous than H.M., helped make signification contribution to the field of memory. The characteristics of the five main modular models are presented, including the most recent one (the perceptual-mnemonic model). The differences as well as how these models converge are highlighted. Different possibilities that could help reconcile unitary and modular approaches are considered. Although modular models differ significantly in many aspects, all converge to the notion that memory for single items and semantic memory could be dissociated from memory for complex material and context-rich episodes. In addition, these models converge concerning the involvement of critical brain structures for these stages: Item and semantic memory, as well as familiarity, are thought to largely depend on anterior subhippocampal areas, while relational, context-rich memory and recollective experiences are thought to largely depend on the hippocampal formation. Copyright © 2010 Elsevier Masson SAS. All rights reserved.

Assessing a Metacognitive Account of Associative Memory Impairments in Temporal Lobe Epilepsy

PubMed Central

Kemp, Steven; Souchay, Céline; Moulin, Chris J. A.

2016-01-01

Previous research has pointed to a deficit in associative recognition in temporal lobe epilepsy (TLE). Associative recognition tasks require discrimination between various combinations of words which have and have not been seen previously (such as old-old or old-new pairs). People with TLE tend to respond to rearranged old-old pairs as if they are “intact” old-old pairs, which has been interpreted as a failure to use a recollection strategy to overcome the familiarity of two recombined words into a new pairing. We examined this specific deficit in the context of metacognition, using postdecision confidence judgements at test. We expected that TLE patients would show inappropriate levels of confidence for associative recognition. Although TLE patients reported lower confidence levels in their responses overall, they were sensitive to the difficulty of varying pair types in their judgements and gave significantly higher confidence ratings for their correct answers. We conclude that a strategic deficit is not at play in the associative recognition of people with TLE, insofar as they are able to monitor the status of their memory system. This adds to a growing body of research suggesting that recollection is impaired in TLE, but not metacognition. PMID:27721992

Midline thalamic neurons are differentially engaged during hippocampus network oscillations.

PubMed

Lara-Vásquez, Ariel; Espinosa, Nelson; Durán, Ernesto; Stockle, Marcelo; Fuentealba, Pablo

2016-07-14

The midline thalamus is reciprocally connected with the medial temporal lobe, where neural circuitry essential for spatial navigation and memory formation resides. Yet, little information is available on the dynamic relationship between activity patterns in the midline thalamus and medial temporal lobe. Here, we report on the functional heterogeneity of anatomically-identified thalamic neurons and the differential modulation of their activity with respect to dorsal hippocampal rhythms in the anesthetized mouse. Midline thalamic neurons expressing the calcium-binding protein calretinin, irrespective of their selective co-expression of calbindin, discharged at overall low levels, did not increase their activity during hippocampal theta oscillations, and their firing rates were inhibited during hippocampal sharp wave-ripples. Conversely, thalamic neurons lacking calretinin discharged at higher rates, increased their activity during hippocampal theta waves, but remained unaffected during sharp wave-ripples. Our results indicate that the midline thalamic system comprises at least two different classes of thalamic projection neuron, which can be partly defined by their differential engagement by hippocampal pathways during specific network oscillations that accompany distinct behavioral contexts. Thus, different midline thalamic neuronal populations might be selectively recruited to support distinct stages of memory processing, consistent with the thalamus being pivotal in the dialogue of cortical circuits.

Using the Cambridge Neuropsychological Test Automated Battery (CANTAB) to assess the cognitive impact of electroconvulsive therapy on visual and visuospatial memory.

PubMed

Falconer, D W; Cleland, J; Fielding, S; Reid, I C

2010-06-01

The cognitive impact of electroconvulsive therapy (ECT) is rarely measured systematically in everyday clinical practice even though patient and clinician acceptance is limited by its adverse affect on memory. If patients are tested it is often with simple paper and pencil tests of visual or verbal memory. There are no reported studies of computerized neuropsychological testing to assess the cognitive impact of ECT on visuospatial memory. Twenty-four patients with severe depression were treated with a course of bilateral ECT and assessed with a battery of visual memory tests within the Cambridge Neuropsychological Test Automated Battery (CANTAB). These included spatial and pattern recognition memory, pattern-location associative learning and a delayed matching to sample test. Testing was carried out before ECT, during ECT, within the week after ECT and 1 month after ECT. Patients showed significant impairments in visual and visuospatial memory both during and within the week after ECT. Most impairments resolved 1 month following ECT; however, significant impairment in spatial recognition memory remained. This is one of only a few studies that have detected anterograde memory deficits more than 2 weeks after treatment. Patients receiving ECT displayed a range of visual and visuospatial deficits over the course of their treatment. These deficits were most prominent for tasks dependent on the use of the right medial temporal lobe; frontal lobe function may also be implicated. The CANTAB appears to be a useful instrument for measuring the adverse cognitive effects of ECT on aspects of visual and visuospatial memory.

NEREC, an effective brain mapping protocol for combined language and long-term memory functions.

PubMed

Perrone-Bertolotti, Marcela; Girard, Cléa; Cousin, Emilie; Vidal, Juan Ricardo; Pichat, Cédric; Kahane, Philippe; Baciu, Monica

2015-12-01

Temporal lobe epilepsy can induce functional plasticity in temporoparietal networks involved in language and long-term memory processing. Previous studies in healthy subjects have revealed the relative difficulty for this network to respond effectively across different experimental designs, as compared to more reactive regions such as frontal lobes. For a protocol to be optimal for clinical use, it has to first show robust effects in a healthy cohort. In this study, we developed a novel experimental paradigm entitled NEREC, which is able to reveal the robust participation of temporoparietal networks in a uniquely combined language and memory task, validated in an fMRI study with healthy subjects. Concretely, NEREC is composed of two runs: (a) an intermixed language-memory task (confrontation naming associated with encoding in nonverbal items, NE) to map language (i.e., word retrieval and lexico-semantic processes) combined with simultaneous long-term verbal memory encoding (NE items named but also explicitly memorized) and (b) a memory retrieval task of items encoded during NE (word recognition, REC) intermixed with new items. Word recognition is based on both perceptual-semantic familiarity (feeling of 'know') and accessing stored memory representations (remembering). In order to maximize the remembering and recruitment of medial temporal lobe structures, we increased REC difficulty by changing the modality of stimulus presentation (from nonverbal during NE to verbal during REC). We report that (a) temporoparietal activation during NE was attributable to both lexico-semantic (language) and memory (episodic encoding and semantic retrieval) processes; that (b) encoding activated the left hippocampus, bilateral fusiform, and bilateral inferior temporal gyri; and that (c) task recognition (recollection) activated the right hippocampus and bilateral but predominant left fusiform gyrus. The novelty of this protocol consists of (a) combining two tasks in one (language and long-term memory encoding/recall) instead of applying isolated tasks to map temporoparietal regions, (b) analyzing NE data based on performances recorded during REC, (c) double-mapping networks involved in naming and in long-term memory encoding and retrieval, (d) focusing on remembering with hippocampal activation and familiarity judgment with lateral temporal cortices activation, and (e) short duration of examination and feasibility. These aspects are of particular interest in patients with TLE, who frequently show impairment of these cognitive functions. Here, we show that the novel protocol is suited for this clinical evaluation. Copyright © 2015 Elsevier Inc. All rights reserved.

Immunocytochemical Mapping of an RDL-Like GABA Receptor Subunit and of GABA in Brain Structures Related to Learning and Memory in the Cricket Acheta domesticus

PubMed Central

Strambi, Colette; Cayre, Myriam; Sattelle, David B.; Augier, Roger; Charpin, Pierre; Strambi, Alain

1998-01-01

The distribution of putative RDL-like GABA receptors and of γ-aminobutyric acid (GABA) in the brain of the adult house cricket Acheta domesticus was studied using specific antisera. Special attention was given to brain structures known to be related to learning and memory. The main immunostaining for the RDL-like GABA receptor was observed in mushroom bodies, in particular the upper part of mushroom body peduncle and the two arms of the posterior calyx. Weaker immunostaining was detected in the distal part of the peduncle and in the α and β lobes. The dorso- and ventrolateral protocerebrum neuropils appeared rich in RDL-like GABA receptors. Staining was also detected in the glomeruli of the antennal lobe, as well as in the ellipsoid body of the central complex. Many neurons clustered in groups exhibit GABA-like immunoreactivity. Tracts that were strongly immunostained innervated both the calyces and the lobes of mushroom bodies. The glomeruli of the antennal lobe, the ellipsoid body, as well as neuropils of the dorso- and ventrolateral protocerebrum were also rich in GABA-like immuno- reactivity. The data demonstrated a good correlation between the distribution of the GABA-like and of the RDL-like GABA receptor immunoreactivity. The prominent distribution of RDL-like GABA receptor subunits, in particular areas of mushroom bodies and antennal lobes, underlines the importance of inhibitory signals in information processing in these major integrative centers of the insect brain. PMID:10454373

The neural substrates of recognition memory for verbal information: spanning the divide between short- and long-term memory.

PubMed

Buchsbaum, Bradley R; Padmanabhan, Aarthi; Berman, Karen Faith

2011-04-01

One of the classic categorical divisions in the history of memory research is that between short-term and long-term memory. Indeed, because memory for the immediate past (a few seconds) and memory for the relatively more remote past (several seconds and beyond) are assumed to rely on distinct neural systems, more often than not, memory research has focused either on short- (or "working memory") or on long-term memory. Using an auditory-verbal continuous recognition paradigm designed for fMRI, we examined how the neural signatures of recognition memory change across an interval of time (from 2.5 to 30 sec) that spans this hypothetical division between short- and long-term memory. The results revealed that activity during successful auditory-verbal item recognition in inferior parietal cortex and the posterior superior temporal lobe was maximal for early lags, whereas, conversely, activity in the left inferior frontal gyrus increased as a function of lag. Taken together, the results reveal that as the interval between item repetitions increases, there is a shift in the distribution of memory-related activity that moves from posterior temporo-parietal cortex (lags 1-4) to inferior frontal regions (lags 5-10), indicating that as time advances, the burden of recognition memory is increasingly placed on top-down retrieval mechanisms that are mediated by structures in inferior frontal cortex.

Preservation of episodic memory in semantic dementia: The importance of regions beyond the medial temporal lobes.

PubMed

Irish, Muireann; Bunk, Steffie; Tu, Sicong; Kamminga, Jody; Hodges, John R; Hornberger, Michael; Piguet, Olivier

2016-01-29

Episodic memory impairment represents one of the hallmark clinical features of patients with Alzheimer's disease (AD) attributable to the degeneration of medial temporal and parietal regions of the brain. In contrast, a somewhat paradoxical profile of relatively intact episodic memory, particularly for non-verbal material, is observed in semantic dementia (SD), despite marked atrophy of the hippocampus. This retrospective study investigated the neural substrates of episodic memory retrieval in 20 patients with a diagnosis of SD and 21 disease-matched cases of AD and compared their performance to that of 35 age- and education-matched healthy older Controls. Participants completed the Rey Complex Figure and the memory subscale of the Addenbrooke's Cognitive Examination-Revised as indices of visual and verbal episodic recall, respectively. Relative to Controls, AD patients showed compromised memory performance on both visual and verbal memory tasks. In contrast, memory deficits in SD were modality-specific occurring exclusively on the verbal task. Controlling for semantic processing ameliorated these deficits in SD, while memory impairments persisted in AD. Voxel-based morphometry analyses revealed significant overlap in the neural correlates of verbal episodic memory in AD and SD with predominantly anteromedial regions, including the bilateral hippocampus, strongly implicated. Controlling for semantic processing negated this effect in SD, however, a distributed network of frontal, medial temporal, and parietal regions was implicated in AD. Our study corroborates the view that episodic memory deficits in SD arise very largely as a consequence of the conceptual loading of traditional tasks. We propose that the functional integrity of frontal and parietal regions enables new learning to occur in SD in the face of significant hippocampal and anteromedial temporal lobe pathology, underscoring the inherent complexity of the episodic memory circuitry. Copyright © 2015 Elsevier Ltd. All rights reserved.

False recall is reduced by damage to the ventromedial prefrontal cortex: implications for understanding the neural correlates of schematic memory.

PubMed

Warren, David E; Jones, Samuel H; Duff, Melissa C; Tranel, Daniel

2014-05-28

Schematic memory, or contextual knowledge derived from experience (Bartlett, 1932), benefits memory function by enhancing retention and speeding learning of related information (Bransford and Johnson, 1972; Tse et al., 2007). However, schematic memory can also promote memory errors, producing false memories. One demonstration is the "false memory effect" of the Deese-Roediger-McDermott (DRM) paradigm (Roediger and McDermott, 1995): studying words that fit a common schema (e.g., cold, blizzard, winter) often produces memory for a nonstudied word (e.g., snow). We propose that frontal lobe regions that contribute to complex decision-making processes by weighting various alternatives, such as ventromedial prefrontal cortex (vmPFC), may also contribute to memory processes by weighting the influence of schematic knowledge. We investigated the role of human vmPFC in false memory by combining a neuropsychological approach with the DRM task. Patients with vmPFC lesions (n = 7) and healthy comparison participants (n = 14) studied word lists that excluded a common associate (the critical item). Recall and recognition tests revealed expected high levels of false recall and recognition of critical items by healthy participants. In contrast, vmPFC patients showed consistently reduced false recall, with significantly fewer intrusions of critical items. False recognition was also marginally reduced among vmPFC patients. Our findings suggest that vmPFC increases the influence of schematically congruent memories, a contribution that may be related to the role of the vmPFC in decision making. These novel neuropsychological results highlight a role for the vmPFC as part of a memory network including the medial temporal lobes and hippocampus (Andrews-Hanna et al., 2010). Copyright © 2014 the authors 0270-6474/14/347677-06$15.00/0.

False Recall Is Reduced by Damage to the Ventromedial Prefrontal Cortex: Implications for Understanding the Neural Correlates of Schematic Memory

PubMed Central

Jones, Samuel H.; Duff, Melissa C.; Tranel, Daniel

2014-01-01

Schematic memory, or contextual knowledge derived from experience (Bartlett, 1932), benefits memory function by enhancing retention and speeding learning of related information (Bransford and Johnson, 1972; Tse et al., 2007). However, schematic memory can also promote memory errors, producing false memories. One demonstration is the “false memory effect” of the Deese–Roediger–McDermott (DRM) paradigm (Roediger and McDermott, 1995): studying words that fit a common schema (e.g., cold, blizzard, winter) often produces memory for a nonstudied word (e.g., snow). We propose that frontal lobe regions that contribute to complex decision-making processes by weighting various alternatives, such as ventromedial prefrontal cortex (vmPFC), may also contribute to memory processes by weighting the influence of schematic knowledge. We investigated the role of human vmPFC in false memory by combining a neuropsychological approach with the DRM task. Patients with vmPFC lesions (n = 7) and healthy comparison participants (n = 14) studied word lists that excluded a common associate (the critical item). Recall and recognition tests revealed expected high levels of false recall and recognition of critical items by healthy participants. In contrast, vmPFC patients showed consistently reduced false recall, with significantly fewer intrusions of critical items. False recognition was also marginally reduced among vmPFC patients. Our findings suggest that vmPFC increases the influence of schematically congruent memories, a contribution that may be related to the role of the vmPFC in decision making. These novel neuropsychological results highlight a role for the vmPFC as part of a memory network including the medial temporal lobes and hippocampus (Andrews-Hanna et al., 2010). PMID:24872571

Clinical utility of the Wechsler Memory Scale - Fourth Edition (WMS-IV) in patients with intractable temporal lobe epilepsy.

PubMed

Bouman, Zita; Elhorst, Didi; Hendriks, Marc P H; Kessels, Roy P C; Aldenkamp, Albert P

2016-02-01

The Wechsler Memory Scale (WMS) is one of the most widely used test batteries to assess memory functions in patients with brain dysfunctions of different etiologies. This study examined the clinical validation of the Dutch Wechsler Memory Scale - Fourth Edition (WMS-IV-NL) in patients with temporal lobe epilepsy (TLE). The sample consisted of 75 patients with intractable TLE, who were eligible for epilepsy surgery, and 77 demographically matched healthy controls. All participants were examined with the WMS-IV-NL. Patients with TLE performed significantly worse than healthy controls on all WMS-IV-NL indices and subtests (p<.01), with the exception of the Visual Working Memory Index including its contributing subtests, as well as the subtests Logical Memory I, Verbal Paired Associates I, and Designs II. In addition, patients with mesiotemporal abnormalities performed significantly worse than patients with lateral temporal abnormalities on the subtests Logical Memory I and Designs II and all the indices (p<.05), with the exception of the Auditory Memory Index and Visual Working Memory Index. Patients with either a left or a right temporal focus performed equally on all WMS-IV-NL indices and subtests (F(15, 50)=.70, p=.78), as well as the Auditory-Visual discrepancy score (t(64)=-1.40, p=.17). The WMS-IV-NL is capable of detecting memory problems in patients with TLE, indicating that it is a sufficiently valid memory battery. Furthermore, the findings support previous research showing that the WMS-IV has limited value in identifying material-specific memory deficits in presurgical patients with TLE. Copyright © 2015 Elsevier Inc. All rights reserved.

Working and strategic memory deficits in schizophrenia

NASA Technical Reports Server (NTRS)

Stone, M.; Gabrieli, J. D.; Stebbins, G. T.; Sullivan, E. V.

1998-01-01

Working memory and its contribution to performance on strategic memory tests in schizophrenia were studied. Patients (n = 18) and control participants (n = 15), all men, received tests of immediate memory (forward digit span), working memory (listening, computation, and backward digit span), and long-term strategic (free recall, temporal order, and self-ordered pointing) and nonstrategic (recognition) memory. Schizophrenia patients performed worse on all tests. Education, verbal intelligence, and immediate memory capacity did not account for deficits in working memory in schizophrenia patients. Reduced working memory capacity accounted for group differences in strategic memory but not in recognition memory. Working memory impairment may be central to the profile of impaired cognitive performance in schizophrenia and is consistent with hypothesized frontal lobe dysfunction associated with this disease. Additional medial-temporal dysfunction may account for the recognition memory deficit.

fMRI studies of successful emotional memory encoding: a quantitative meta-analysis

PubMed Central

Murty, Vishnu P.; Ritchey, Maureen; Adcock, R. Alison; LaBar, Kevin S.

2010-01-01

Over the past decade, fMRI techniques have been increasingly used to interrogate the neural correlates of successful emotional memory encoding. These investigations have typically aimed to either characterize the contributions of the amygdala and medial temporal lobe (MTL) memory system, replicating results in animals, or delineate the neural correlates of specific behavioral phenomena. It has remained difficult, however, to synthesize these findings into a systems neuroscience account of how networks across the whole brain support the enhancing effects of emotion on memory encoding. To this end, the present study employed a meta-analytic approach using activation likelihood estimates to assess the anatomical specificity and reliability of event-related fMRI activations related to successful memory encoding for emotional versus neutral information. The meta-analysis revealed consistent clusters within bilateral amygdala, anterior hippocampus, anterior and posterior parahippocampal gyrus, the ventral visual stream, left lateral prefrontal cortex and right ventral parietal cortex. The results within the amygdala and MTL support a wealth of findings from the animal literature linking these regions to arousal-mediated memory effects. The consistency of findings in cortical targets, including the visual, prefrontal, and parietal cortices, underscores the importance of generating hypotheses regarding their participation in emotional memory formation. In particular, we propose that the amygdala interacts with these structures to promote enhancements in perceptual processing, semantic elaboration, and attention, which serve to benefit subsequent memory for emotional material. These findings may motivate future research on emotional modulation of widespread neural systems and the implications of this modulation for cognition. PMID:20688087

Famous face identification in temporal lobe epilepsy: Support for a multimodal integration model of semantic memory

PubMed Central

Drane, Daniel L.; Ojemann, Jeffrey G.; Phatak, Vaishali; Loring, David W.; Gross, Robert E.; Hebb, Adam O.; Silbergeld, Daniel L.; Miller, John W.; Voets, Natalie L.; Saindane, Amit M.; Barsalou, Lawrence; Meador, Kimford J.; Ojemann, George A.; Tranel, Daniel

2012-01-01

This study aims to demonstrate that the left and right anterior temporal lobes (ATLs) perform critical but unique roles in famous face identification, with damage to either leading to differing deficit patterns reflecting decreased access to lexical or semantic concepts but not their degradation. Famous face identification was studied in 22 presurgical and 14 postsurgical temporal lobe epilepsy (TLE) patients and 20 healthy comparison subjects using free recall and multiple choice (MC) paradigms. Right TLE patients exhibited presurgical deficits in famous face recognition, and postsurgical deficits in both famous face recognition and familiarity judgments. However, they did not exhibit any problems with naming before or after surgery. In contrast, left TLE patients demonstrated both pre-and postsurgical deficits in famous face naming but no significant deficits in recognition or familiarity. Double dissociations in performance between groups were alleviated by altering task demands. Postsurgical right TLE patients provided with MC options correctly identified greater than 70% of famous faces they initially rated as unfamiliar. Left TLE patients accurately chose the name for nearly all famous faces they recognized (based on their verbal description) but initially failed to name, although they tended to rapidly lose access to this name. We believe alterations in task demands activate alternative routes to semantic and lexical networks, demonstrating that unique pathways to such stored information exist, and suggesting a different role for each ATL in identifying visually presented famous faces. The right ATL appears to play a fundamental role in accessing semantic information from a visual route, with the left ATL serving to link semantic information to the language system to produce a specific name. These findings challenge several assumptions underlying amodal models of semantic memory, and provide support for the integrated multimodal theories of semantic memory and a distributed representation of concepts. PMID:23040175

Famous face identification in temporal lobe epilepsy: support for a multimodal integration model of semantic memory.

PubMed

Drane, Daniel L; Ojemann, Jeffrey G; Phatak, Vaishali; Loring, David W; Gross, Robert E; Hebb, Adam O; Silbergeld, Daniel L; Miller, John W; Voets, Natalie L; Saindane, Amit M; Barsalou, Lawrence; Meador, Kimford J; Ojemann, George A; Tranel, Daniel

2013-06-01

This study aims to demonstrate that the left and right anterior temporal lobes (ATLs) perform critical but unique roles in famous face identification, with damage to either leading to differing deficit patterns reflecting decreased access to lexical or semantic concepts but not their degradation. Famous face identification was studied in 22 presurgical and 14 postsurgical temporal lobe epilepsy (TLE) patients and 20 healthy comparison subjects using free recall and multiple choice (MC) paradigms. Right TLE patients exhibited presurgical deficits in famous face recognition, and postsurgical deficits in both famous face recognition and familiarity judgments. However, they did not exhibit any problems with naming before or after surgery. In contrast, left TLE patients demonstrated both pre- and postsurgical deficits in famous face naming but no significant deficits in recognition or familiarity. Double dissociations in performance between groups were alleviated by altering task demands. Postsurgical right TLE patients provided with MC options correctly identified greater than 70% of famous faces they initially rated as unfamiliar. Left TLE patients accurately chose the name for nearly all famous faces they recognized (based on their verbal description) but initially failed to name, although they tended to rapidly lose access to this name. We believe alterations in task demands activate alternative routes to semantic and lexical networks, demonstrating that unique pathways to such stored information exist, and suggesting a different role for each ATL in identifying visually presented famous faces. The right ATL appears to play a fundamental role in accessing semantic information from a visual route, with the left ATL serving to link semantic information to the language system to produce a specific name. These findings challenge several assumptions underlying amodal models of semantic memory, and provide support for the integrated multimodal theories of semantic memory and a distributed representation of concepts. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effects of the BDNF Val66Met polymorphism and met allele load on declarative memory related neural networks.

PubMed

Dodds, Chris M; Henson, Richard N; Suckling, John; Miskowiak, Kamilla W; Ooi, Cinly; Tait, Roger; Soltesz, Fruzsina; Lawrence, Phil; Bentley, Graham; Maltby, Kay; Skeggs, Andrew; Miller, Sam R; McHugh, Simon; Bullmore, Edward T; Nathan, Pradeep J

2013-01-01

It has been suggested that the BDNF Val66Met polymorphism modulates episodic memory performance via effects on hippocampal neural circuitry. However, fMRI studies have yielded inconsistent results in this respect. Moreover, very few studies have examined the effect of met allele load on activation of memory circuitry. In the present study, we carried out a comprehensive analysis of the effects of the BDNF polymorphism on brain responses during episodic memory encoding and retrieval, including an investigation of the effect of met allele load on memory related activation in the medial temporal lobe. In contrast to previous studies, we found no evidence for an effect of BDNF genotype or met load during episodic memory encoding. Met allele carriers showed increased activation during successful retrieval in right hippocampus but this was contrast-specific and unaffected by met allele load. These results suggest that the BDNF Val66Met polymorphism does not, as previously claimed, exert an observable effect on neural systems underlying encoding of new information into episodic memory but may exert a subtle effect on the efficiency with which such information can be retrieved.

Impaired category fluency in medial temporal lobe amnesia: the role of episodic memory.

PubMed

Greenberg, Daniel L; Keane, Margaret M; Ryan, Lee; Verfaellie, Mieke

2009-09-02

Memory tasks are often classified as semantic or episodic, but recent research shows that these types of memory are highly interactive. Category fluency, for example, is generally considered to reflect retrieval from semantic memory, but behavioral evidence suggests that episodic memory is also involved: participants frequently draw on autobiographical experiences while generating exemplars of certain categories. Neuroimaging studies accordingly have reported increased medial temporal lobe (MTL) activation during exemplar generation. Studies of fluency in MTL amnesics have yielded mixed results but were not designed to determine the precise contributions of episodic memory. We addressed this issue by asking MTL amnesics and controls to generate exemplars of three types of categories. One type tended to elicit autobiographical and spatial retrieval strategies (AS). Another type elicited strategies that were autobiographical but nonspatial (AN). The third type elicited neither autobiographical nor spatial strategies (N). Amnesic patients and control participants generated exemplars for eight categories of each type. Patients were impaired on all category types but were more impaired on AS and AN categories. After covarying for phonemic fluency (total FAS score), the N category impairment was not significant, but the impairment on AS and AN categories remained. The same results were obtained for patients with lesions restricted to the MTL and those with more extensive lesions. We conclude that patients' episodic memory impairment hindered their performance on this putatively semantic task. This interaction between episodic and semantic memory might partially account for fluency deficits seen in aging, mild cognitive impairment, and Alzheimer's disease.

The hierarchical and functional connectivity of higher-order cognitive mechanisms: neurorobotic model to investigate the stability and flexibility of working memory

PubMed Central

Alnajjar, Fady; Yamashita, Yuichi; Tani, Jun

2013-01-01

Higher-order cognitive mechanisms (HOCM), such as planning, cognitive branching, switching, etc., are known to be the outcomes of a unique neural organizations and dynamics between various regions of the frontal lobe. Although some recent anatomical and neuroimaging studies have shed light on the architecture underlying the formation of such mechanisms, the neural dynamics and the pathways in and between the frontal lobe to form and/or to tune the stability level of its working memory remain controversial. A model to clarify this aspect is therefore required. In this study, we propose a simple neurocomputational model that suggests the basic concept of how HOCM, including the cognitive branching and switching in particular, may mechanistically emerge from time-based neural interactions. The proposed model is constructed such that its functional and structural hierarchy mimics, to a certain degree, the biological hierarchy that is believed to exist between local regions in the frontal lobe. Thus, the hierarchy is attained not only by the force of the layout architecture of the neural connections but also through distinct types of neurons, each with different time properties. To validate the model, cognitive branching and switching tasks were simulated in a physical humanoid robot driven by the model. Results reveal that separation between the lower and the higher-level neurons in such a model is an essential factor to form an appropriate working memory to handle cognitive branching and switching. The analyses of the obtained result also illustrates that the breadth of this separation is important to determine the characteristics of the resulting memory, either static memory or dynamic memory. This work can be considered as a joint research between synthetic and empirical studies, which can open an alternative research area for better understanding of brain mechanisms. PMID:23423881

The hierarchical and functional connectivity of higher-order cognitive mechanisms: neurorobotic model to investigate the stability and flexibility of working memory.

PubMed

Alnajjar, Fady; Yamashita, Yuichi; Tani, Jun

2013-01-01

Higher-order cognitive mechanisms (HOCM), such as planning, cognitive branching, switching, etc., are known to be the outcomes of a unique neural organizations and dynamics between various regions of the frontal lobe. Although some recent anatomical and neuroimaging studies have shed light on the architecture underlying the formation of such mechanisms, the neural dynamics and the pathways in and between the frontal lobe to form and/or to tune the stability level of its working memory remain controversial. A model to clarify this aspect is therefore required. In this study, we propose a simple neurocomputational model that suggests the basic concept of how HOCM, including the cognitive branching and switching in particular, may mechanistically emerge from time-based neural interactions. The proposed model is constructed such that its functional and structural hierarchy mimics, to a certain degree, the biological hierarchy that is believed to exist between local regions in the frontal lobe. Thus, the hierarchy is attained not only by the force of the layout architecture of the neural connections but also through distinct types of neurons, each with different time properties. To validate the model, cognitive branching and switching tasks were simulated in a physical humanoid robot driven by the model. Results reveal that separation between the lower and the higher-level neurons in such a model is an essential factor to form an appropriate working memory to handle cognitive branching and switching. The analyses of the obtained result also illustrates that the breadth of this separation is important to determine the characteristics of the resulting memory, either static memory or dynamic memory. This work can be considered as a joint research between synthetic and empirical studies, which can open an alternative research area for better understanding of brain mechanisms.

Short-term and long-term memory in early temporal lobe dysfunction.

PubMed

Hershey, T; Craft, S; Glauser, T A; Hale, S

1998-01-01

Following medial temporal damage, mature humans are impaired in retaining new information over long delays but not short delays. The question of whether a similar dissociation occurs in children was addressed by testing children (ages 7-16) with unilateral temporal lobe epilepsy (TLE) and controls on short- and long-term memory tasks, including a spatial delayed response task (SDR). Early-onset TLE did not affect performance on short delays on SDR, but it did impair performance at the longest delay (60 s), similar to adults with unilateral medial temporal damage. In addition, early-onset TLE affected performance on pattern recall, spatial span, and verbal span with rehearsal interference. No differences were found on story recall or on a response inhibition task.

Functional independence within the self-memory system: new insights from two cases of developmental amnesia.

PubMed

Picard, Laurence; Mayor-Dubois, Claire; Maeder, Philippe; Kalenzaga, Sandrine; Abram, Maria; Duval, Céline; Eustache, Francis; Roulet-Perez, Eliane; Piolino, Pascale

2013-06-01

Neuropsychological and neuroimaging data suggest that the self-memory system can be fractionated into three functionally independent systems processing personal information at several levels of abstraction, including episodic memories of one's life (episodic autobiographical memory, EAM), semantic knowledge of facts about one's life (semantic autobiographical memory, SAM), and semantic knowledge of one's personality [conceptual self, (CS)]. Through the study of two developmental amnesic patients suffering of neonatal brain injuries, we explored how the different facets of the self-memory system develop when growing up with bilateral hippocampal atrophy. Neuropsychological evaluations showed that both of them suffered from dramatic episodic learning disability with no sense of recollection (Remember/Know procedure), whereas their semantic abilities differed, being completely preserved (Valentine) or not (Jocelyn). Magnetic resonance imaging, including quantitative volumetric measurements of the hippocampus and adjacent (entorhinal, perirhinal, and temporopolar) cortex, showed severe bilateral atrophy of the hippocampus in both patients, with additional atrophy of adjacent cortex in Jocelyn. Exploration of EAM and SAM according to lifetime periods covering the entire lifespan (TEMPAu task, Piolino et al., 2009) showed that both patients had marked impairments in EAM, as they lacked specificity, details and sense of recollection, whereas SAM was completely normal in Valentine, but impaired in Jocelyn. Finally, measures of patients' CS (Tennessee Self-Concept Scale, Fitts and Warren, 1996), checked by their mothers, were generally within normal range, but both patients showed a more positive self-concept than healthy controls. These two new cases support a modular account of the medial-temporal lobe with episodic memory and recollection depending on the hippocampus, and semantic memory and familiarity on adjacent cortices. Furthermore, they highlight developmental episodic and semantic functional independence within the self-memory system suggesting that SAM and CS may be acquired without episodic memories. Copyright © 2012 Elsevier Ltd. All rights reserved.

The Influence of Pre-Deployment Neurocognitive Functioning on Post-Deployment PTSD Symptom Outcomes Among Iraq-Deployed Army Soldiers

DTIC Science & Technology

2009-01-01

Autobiographical memory studies of non-trauma-exposed samples have dem- onstrated that decreased visual input reduces the recollection of autobiographical events...Rubin, Burt, & Fifeld, 2003), and damage to the occipital lobe impedes autobiographical memory (Greenberg & Rubin, 2003). Although speculative. it is...McNally, RJ .. Lasko. N.B .. Macklin. M.L.. & Pitman, RK. (1995). Autobiographical memory disturbance in combat-related post- traumatic stress disorder

Role of Amygdala Connectivity in the Persistence of Emotional Memories Over Time: An Event-Related fMRI Investigation

PubMed Central

Dolcos, Florin; Cabeza, Roberto

2008-01-01

According to the consolidation hypothesis, enhanced memory for emotional information reflects the modulatory effect of the amygdala on the medial temporal lobe (MTL) memory system during consolidation. Although there is evidence that amygdala–MTL connectivity enhances memory for emotional stimuli, it remains unclear whether this enhancement increases over time, as consolidation processes unfold. To investigate this, we used functional magnetic resonance imaging to measure encoding activity predicting memory for emotionally negative and neutral pictures after short (20-min) versus long (1-week) delays. Memory measures distinguished between vivid remembering (recollection) and feelings of knowing (familiarity). Consistent with the consolidation hypothesis, the persistence of recollection over time (long divided by short) was greater for emotional than neutral pictures. Activity in the amygdala predicted subsequent memory to a greater extent for emotional than neutral pictures. Although this advantage did not vary with delay, the contribution of amygdala–MTL connectivity to subsequent memory for emotional items increased over time. Moreover, both this increase in connectivity and amygdala activity itself were correlated with individual differences in recollection persistence for emotional but not neutral pictures. These results suggest that the amygdala and its connectivity with the MTL are critical to sustaining emotional memories over time, consistent with the consolidation hypothesis. PMID:18375529

Task activation and functional connectivity show concordant memory laterality in temporal lobe epilepsy.

PubMed

Sideman, Noah; Chaitanya, Ganne; He, Xiaosong; Doucet, Gaelle; Kim, Na Young; Sperling, Michael R; Sharan, Ashwini D; Tracy, Joseph I

2018-04-01

In epilepsy, asymmetries in the organization of mesial temporal lobe (MTL) functions help determine the cognitive risk associated with procedures such as anterior temporal lobectomy. Past studies have investigated the change/shift in a visual episodic memory laterality index (LI) in mesial temporal lobe structures through functional magnetic resonance imaging (fMRI) task activations. Here, we examine whether underlying task-related functional connectivity (FC) is concordant with such standard fMRI laterality measures. A total of 56 patients with temporal lobe epilepsy (TLE) (Left TLE [LTLE]: 31; Right TLE [RTLE]: 25) and 34 matched healthy controls (HC) underwent fMRI scanning during performance of a scene encoding task (SET). We assessed an activation-based LI of the hippocampal gyrus (HG) and parahippocampal gyrus (PHG) during the SET and its correspondence with task-related FC measures. Analyses involving the HG and PHG showed that the patients with LTLE had a consistently higher LI (right-lateralized) than that of the HC and group with RTLE, indicating functional reorganization. The patients with RTLE did not display a reliable contralateral shift away from the pathology, with the mesial structures showing quite distinct laterality patterns (HG, no laterality bias; PHG, no evidence of LI shift). The FC data for the group with LTLE provided confirmation of reorganization effects, revealing that a rightward task LI may be based on underlying connections between several left-sided regions (middle/superior occipital and left medial frontal gyri) and the right PHG. The FCs between the right HG and left anterior cingulate/medial frontal gyri were also observed in LTLE. Importantly, the data demonstrate that the areas involved in the LTLE task activation shift to the right hemisphere showed a corresponding increase in task-related FCs between the hemispheres. Altered laterality patterns based on mesial temporal lobe epilepsy (MTLE) pathology manifest as several different phenotypes, varying according to side of seizure onset and the specific mesial structures involved. There is good correspondence between task LI activation and FC patterns in the setting of LTLE, suggesting that reliable visual episodic memory reorganization may require both a shift in nodal activation and a change in nodal connectivity with mesial temporal structures involved in memory. Copyright © 2018. Published by Elsevier Inc.

Dissociating retrieval success from incidental encoding activity during emotional memory retrieval, in the medial temporal lobe

PubMed Central

Shafer, Andrea T.; Dolcos, Florin

2014-01-01

The memory-enhancing effect of emotion has been linked to the engagement of emotion- and memory-related medial temporal lobe (MTL) regions (amygdala-AMY; hippocampus-HC; parahippocampus-PHC), during both encoding and retrieval. However, recognition tasks used to investigate the neural correlates of retrieval make it difficult to distinguish MTL engagement linked to retrieval success (RS) from that linked to incidental encoding success (ES) during retrieval. This issue has been investigated for retrieval of non-emotional memories, but not for emotional memory retrieval. To address this, we used event-related functional MRI in conjunction with an emotional distraction and two episodic memory tasks (one testing memory for distracter items and the other testing memory for new/lure items presented in the first memory task). This paradigm allowed for dissociation of MTL activity specifically linked to RS from that linked to both RS and incidental ES during retrieval. There were two novel findings regarding the neural correlates of emotional memory retrieval. First, greater emotional RS was identified bilaterally in AMY, HC, and PHC. However, AMY activity was most impacted when accounting for ES activity, as only RS activity in left AMY was dissociated from ES activity during retrieval, whereas portions of HC and PHC showing greater emotional RS were largely uninvolved in ES. Second, an earlier and more anteriorly spread response (left AMY and bilateral HC, PHC) was linked to greater emotional RS activity, whereas a later and more posteriorly localized response (right posterior PHC) was linked to greater neutral RS activity. These findings shed light on MTL mechanisms subserving the memory-enhancing effect of emotion at retrieval. PMID:24917798

Electrical Stimulation in Hippocampus and Entorhinal Cortex Impairs Spatial and Temporal Memory.

PubMed

Goyal, Abhinav; Miller, Jonathan; Watrous, Andrew J; Lee, Sang Ah; Coffey, Tom; Sperling, Michael R; Sharan, Ashwini; Worrell, Gregory; Berry, Brent; Lega, Bradley; Jobst, Barbara C; Davis, Kathryn A; Inman, Cory; Sheth, Sameer A; Wanda, Paul A; Ezzyat, Youssef; Das, Sandhitsu R; Stein, Joel; Gorniak, Richard; Jacobs, Joshua

2018-05-09

The medial temporal lobe (MTL) is widely implicated in supporting episodic memory and navigation, but its precise functional role in organizing memory across time and space remains elusive. Here we examine the specific cognitive processes implemented by MTL structures (hippocampus and entorhinal cortex) to organize memory by using electrical brain stimulation, leveraging its ability to establish causal links between brain regions and features of behavior. We studied neurosurgical patients of both sexes who performed spatial-navigation and verbal-episodic memory tasks while brain stimulation was applied in various regions during learning. During the verbal memory task, stimulation in the MTL disrupted the temporal organization of encoded memories such that items learned with stimulation tended to be recalled in a more randomized order. During the spatial task, MTL stimulation impaired subjects' abilities to remember items located far away from boundaries. These stimulation effects were specific to the MTL. Our findings thus provide the first causal demonstration in humans of the specific memory processes that are performed by the MTL to encode when and where events occurred. SIGNIFICANCE STATEMENT Numerous studies have implicated the medial temporal lobe (MTL) in encoding spatial and temporal memories, but they have not been able to causally demonstrate the nature of the cognitive processes by which this occurs in real-time. Electrical brain stimulation is able to demonstrate causal links between a brain region and a given function with high temporal precision. By examining behavior in a memory task as subjects received MTL stimulation, we provide the first causal evidence demonstrating the role of the MTL in organizing the spatial and temporal aspects of episodic memory. Copyright © 2018 the authors 0270-6474/18/384471-11$15.00/0.

Network reconfiguration and working memory impairment in mesial temporal lobe epilepsy.

PubMed

Campo, Pablo; Garrido, Marta I; Moran, Rosalyn J; García-Morales, Irene; Poch, Claudia; Toledano, Rafael; Gil-Nagel, Antonio; Dolan, Raymond J; Friston, Karl J

2013-05-15

Mesial temporal lobe epilepsy (mTLE) is the most prevalent form of focal epilepsy, and hippocampal sclerosis (HS) is considered the most frequent associated pathological finding. Recent connectivity studies have shown that abnormalities, either structural or functional, are not confined to the affected hippocampus, but can be found in other connected structures within the same hemisphere, or even in the contralesional hemisphere. Despite the role of hippocampus in memory functions, most of these studies have explored network properties at resting state, and in some cases compared connectivity values with neuropsychological memory scores. Here, we measured magnetoencephalographic responses during verbal working memory (WM) encoding in left mTLE patients and controls, and compared their effective connectivity within a frontotemporal network using dynamic causal modelling. Bayesian model comparison indicated that the best model included bilateral, forward and backward connections, linking inferior temporal cortex (ITC), inferior frontal cortex (IFC), and the medial temporal lobe (MTL). Test for differences in effective connectivity revealed that patients exhibited decreased ipsilesional MTL-ITC backward connectivity, and increased bidirectional IFC-MTL connectivity in the contralesional hemisphere. Critically, a negative correlation was observed between these changes in patients, with decreases in ipsilesional coupling among temporal sources associated with increases contralesional frontotemporal interactions. Furthermore, contralesional frontotemporal interactions were inversely related to task performance and level of education. The results demonstrate that unilateral sclerosis induced local and remote changes in the dynamic organization of a distributed network supporting verbal WM. Crucially, pre-(peri) morbid factors (educational level) were reflected in both cognitive performance and (putative) compensatory changes in physiological coupling. Copyright © 2013 Elsevier Inc. All rights reserved.

Common and unique gray matter correlates of episodic memory dysfunction in frontotemporal dementia and Alzheimer's disease.

PubMed

Irish, Muireann; Piguet, Olivier; Hodges, John R; Hornberger, Michael

2014-04-01

Conflicting evidence exists regarding the integrity of episodic memory in the behavioral variant of frontotemporal dementia (bvFTD). Recent converging evidence suggests that episodic memory in progressive cases of bvFTD is compromised to the same extent as in Alzheimer's disease (AD). The underlying neural substrates of these episodic memory deficits, however, likely differ contingent on dementia type. In this study we sought to elucidate the neural substrates of episodic memory performance, across recall and recognition tasks, in both patient groups using voxel-based morphometry (VBM) analyses. We predicted that episodic memory dysfunction would be apparent in both patient groups but would relate to divergent patterns of neural atrophy specific to each dementia type. We assessed episodic memory, across verbal and visual domains, in 19 bvFTD, 18 AD patients, and 19 age- and education-matched controls. Behaviorally, patient groups were indistinguishable for immediate and delayed recall, across verbal and visual domains. Whole-brain VBM analyses revealed regions commonly implicated in episodic retrieval across groups, namely the right temporal pole, right frontal lobe, left paracingulate gyrus, and right anterior hippocampus. Divergent neural networks specific to each group were also identified. Whereas a widespread network including posterior regions such as the posterior cingulate cortex, parietal and occipital cortices was exclusively implicated in AD, the frontal and anterior temporal lobes underpinned the episodic memory deficits in bvFTD. Our results point to distinct neural changes underlying episodic memory decline specific to each dementia syndrome. Copyright © 2013 Wiley Periodicals, Inc.

Beyond the FFA: The Role of the Ventral Anterior Temporal Lobes in Face Processing

PubMed Central

Collins, Jessica A.; Olson, Ingrid R.

2014-01-01

Extensive research has supported the existence of a specialized face-processing network that is distinct from the visual processing areas used for general object recognition. The majority of this work has been aimed at characterizing the response properties of the fusiform face area (FFA) and the occipital face area (OFA), which together are thought to constitute the core network of brain areas responsible for facial identification. Although accruing evidence has shown that face-selective patches in the ventral anterior temporal lobes (vATLs) are interconnected with the FFA and OFA, and that they play a role in facial identification, the relative contribution of these brain areas to the core face-processing network has remained unarticulated. Here we review recent research critically implicating the vATLs in face perception and memory. We propose that current models of face processing should be revised such that the ventral anterior temporal lobes serve a centralized role in the visual face-processing network. We speculate that a hierarchically organized system of face processing areas extends bilaterally from the inferior occipital gyri to the vATLs, with facial representations becoming increasingly complex and abstracted from low-level perceptual features as they move forward along this network. The anterior temporal face areas may serve as the apex of this hierarchy, instantiating the final stages of face recognition. We further argue that the anterior temporal face areas are ideally suited to serve as an interface between face perception and face memory, linking perceptual representations of individual identity with person-specific semantic knowledge. PMID:24937188

Cerebral Blood Flow and BOLD Responses to a Memory Encoding Task: A Comparison Between Healthy Young and Elderly Adults

PubMed Central

Restom, Khaled; Bangen, Katherine J.; Bondi, Mark W.; Perthen, Joanna E.; Liu, Thomas T.

2007-01-01

Functional magnetic resonance imaging (fMRI) studies of the medial temporal lobe have primarily made use of the blood oxygenation level dependent (BOLD) response to neural activity. The interpretation of the BOLD signal as a measure of medial temporal lobe function can be complicated, however, by changes in the cerebrovascular system that can occur with both normal aging and age-related diseases, such as Alzheimer's disease. Quantitative measures of the functional cerebral blood flow (CBF) response offer a useful complement to BOLD measures, and have been shown to aid in the interpretation of fMRI studies. Despite these potential advantages, the application of ASL to fMRI studies of cognitive tasks and at-risk populations has been limited. In this study, we demonstrate the application of ASL fMRI to obtain measures of the CBF and BOLD responses to the encoding of natural scenes in healthy young (mean 25 years) and elderly (mean 74 years) adults. The percent CBF increase in the medial temporal lobe was significantly higher in the older adults, whereas the CBF levels during baseline and task conditions and during a separate resting-state scan were significantly lower in the older group. The older adults also showed slightly higher values for the BOLD response amplitude and the absolute change in CBF, but the age group differences were not significant. The percent CBF and BOLD responses are consistent with an age-related increase in the cerebral metabolic rate of oxygen metabolism (CMRO2) response to memory encoding. PMID:17590353

Evidence for degraded low frequency verbal concepts in left resected temporal lobe epilepsy patients.

PubMed

Visser, M; Forn, C; Lambon Ralph, M A; Hoffman, P; Gómez Ibáñez, A; Sunajuán, Ana; Rosell Negre, P; Villanueva, V; Ávila, C

2018-06-01

According to a large neuropsychological and neuroimaging literature, the bilateral anterior temporal lobe (ATL) is a core region for semantic processing. It seems therefore surprising that semantic memory appears to be preserved in temporal lobe epilepsy (TLE) patients with unilateral ATL resection. However, recent work suggests that the bilateral semantic system is relatively robust against unilateral damage and semantic impairments under these circumstances only become apparent with low frequency specific concepts. In addition, neuroimaging studies have shown that the function of the left and right ATLs differ and therefore left or right ATL resection should lead to a different pattern of impairment. The current study investigated hemispheric differences in the bilateral semantic system by comparing left and right resected TLE patients during verbal semantic processing of low frequency concepts. Picture naming and semantic comprehension tasks with varying word frequencies were included to investigate the pattern of impairment. Left but not right TLE patients showed impaired semantic processing, which was particularly apparent on low frequency items. This indicates that, for verbal information, the bilateral semantic system is more sensitive to damage in the left compared to the right ATL, which is in line with theories that attribute a more prominent role to the left ATL due to connections with pre-semantic verbal regions. Copyright © 2018 Elsevier Ltd. All rights reserved.

Receiver Operating Characteristic Curve Analysis of Wechsler Memory Scale-Revised Scores in Epilepsy Surgery Candidates.

ERIC Educational Resources Information Center

Barr, William B.

1997-01-01

Wechsler Memory Scale-Revised (WMS-R) scores were analyzed for 82 epilepsy surgery candidates and used in combination with receiver operating characteristic curves to classify patients with left (LTL) and right (RTL) temporal lobe seizure onset. Results indicate that WMS-R scores used alone or in combination provide relatively poor discrimination…

The neural correlates of specific versus general autobiographical memory construction and elaboration

PubMed Central

Holland, Alisha C.; Addis, Donna Rose; Kensinger, Elizabeth A.

2011-01-01

We examined the neural correlates of specific (i.e., unique to time and place) and general (i.e., extended in or repeated over time) autobiographical memories (AMs) during their initial construction and later elaboration phases. The construction and elaboration of specific and general events engaged a widely distributed set of regions previously associated with AM recall. Specific (vs. general) event construction preferentially engaged prefrontal and medial temporal lobe regions known to be critical for memory search and retrieval processes. General event elaboration was differentiated from specific event elaboration by extensive right-lateralized prefrontal cortex (PFC) activity. Interaction analyses confirmed that PFC activity was disproportionately engaged by specific AMs during construction, and general AMs during elaboration; a similar pattern was evident in regions of the left lateral temporal lobe. These neural differences between specific and general AM construction and elaboration were largely unrelated to reported differences in the level of detail recalled about each type of event. PMID:21803063

MEDIAL TEMPORAL LOBE CONTRIBUTIONS TO FUTURE THINKING: EVIDENCE FROM NEUROIMAGING AND AMNESIA.

PubMed

Verfaellie, Mieke; Race, Elizabeth; Keane, Margaret M

2012-09-01

Following early amnesic case reports, there is now considerable evidence suggesting a link between remembering the past and envisioning the future. This link is evident in the overlap in neural substrates as well as cognitive processes involved in both kinds of tasks. While constructing a future narrative requires multiple processes, neuroimaging and lesion data converge on a critical role for the medial temporal lobes (MTL) in retrieving and recombining details from memory in the service of novel simulations. Deficient detail retrieval and recombination may lead to impairments not only in episodic, but also in semantic prospection. MTL contributions to scene construction and mental time travel may further compound impairments in amnesia on tasks that pose additional demands on these processes, but are unlikely to form the core deficit underlying amnesics' cross-domain future thinking impairment. Future studies exploring the role of episodic memory in other forms of self-projection or future-oriented behaviour may elucidate further the adaptive role of memory.

Hippocampus, perirhinal cortex, and complex visual discriminations in rats and humans

PubMed Central

Hales, Jena B.; Broadbent, Nicola J.; Velu, Priya D.

2015-01-01

Structures in the medial temporal lobe, including the hippocampus and perirhinal cortex, are known to be essential for the formation of long-term memory. Recent animal and human studies have investigated whether perirhinal cortex might also be important for visual perception. In our study, using a simultaneous oddity discrimination task, rats with perirhinal lesions were impaired and did not exhibit the normal preference for exploring the odd object. Notably, rats with hippocampal lesions exhibited the same impairment. Thus, the deficit is unlikely to illuminate functions attributed specifically to perirhinal cortex. Both lesion groups were able to acquire visual discriminations involving the same objects used in the oddity task. Patients with hippocampal damage or larger medial temporal lobe lesions were intact in a similar oddity task that allowed participants to explore objects quickly using eye movements. We suggest that humans were able to rely on an intact working memory capacity to perform this task, whereas rats (who moved slowly among the objects) needed to rely on long-term memory. PMID:25593294

MEDIAL TEMPORAL LOBE CONTRIBUTIONS TO FUTURE THINKING: EVIDENCE FROM NEUROIMAGING AND AMNESIA

PubMed Central

Verfaellie, Mieke; Race, Elizabeth; Keane, Margaret M.

2013-01-01

Following early amnesic case reports, there is now considerable evidence suggesting a link between remembering the past and envisioning the future. This link is evident in the overlap in neural substrates as well as cognitive processes involved in both kinds of tasks. While constructing a future narrative requires multiple processes, neuroimaging and lesion data converge on a critical role for the medial temporal lobes (MTL) in retrieving and recombining details from memory in the service of novel simulations. Deficient detail retrieval and recombination may lead to impairments not only in episodic, but also in semantic prospection. MTL contributions to scene construction and mental time travel may further compound impairments in amnesia on tasks that pose additional demands on these processes, but are unlikely to form the core deficit underlying amnesics’ cross-domain future thinking impairment. Future studies exploring the role of episodic memory in other forms of self-projection or future-oriented behaviour may elucidate further the adaptive role of memory. PMID:23447709

Jazz, guitar, and neurosurgery: the Pat Martino case report.

PubMed

Galarza, Marcelo; Isaac, Claire; Pellicer, Olga; Mayes, Andrew; Broks, Paul; Montaldi, Daniela; Denby, Christine; Simeone, Frederick

2014-01-01

We present the case of a professional jazz guitarist with temporal lobe epilepsy secondary to an arteriovenous cerebral malformation. The patient underwent a left temporal lobectomy in 1980. After surgery, he presented with severe retrograde amnesia and complete loss of musical interest and capabilities. The patient's musical abilities recovered over time, and he regained his previous virtuoso status. In 2007, his medical history, neuropsychologic functions, and structural magnetic resonance imaging study were examined and revealed a remarkable degree of recovery of memory and musical abilities in the context of extensive temporal lobe resection. The neuropsychologic findings and neuroanatomic features of the magnetic resonance imaging study were analyzed to try to understand the high degree of recovery of both long-term memory and musical processing abilities in this musician. This case reveals the possibility of an unusual degree of cerebral plasticity and reorganization. Additionally, it emphasizes the question of musical virtuosity. This report shows that the musical capabilities of professional musicians, in specific cases, can completely recover even when much of the left temporal lobe has been removed. Copyright © 2014 Elsevier Inc. All rights reserved.

Compensation or inhibitory failure? Testing hypotheses of age-related right frontal lobe involvement in verbal memory ability using structural and diffusion MRI

PubMed Central

Cox, Simon R.; Bastin, Mark E.; Ferguson, Karen J.; Allerhand, Mike; Royle, Natalie A.; Maniega, Susanna Muñoz; Starr, John M.; MacLullich, Alasdair M.J.; Wardlaw, Joanna M.; Deary, Ian J.; MacPherson, Sarah E.

2015-01-01

Functional neuroimaging studies report increased right prefrontal cortex (PFC) involvement during verbal memory tasks amongst low-scoring older individuals, compared to younger controls and their higher-scoring contemporaries. Some propose that this reflects inefficient use of neural resources through failure of the left PFC to inhibit non-task-related right PFC activity, via the anterior corpus callosum (CC). For others, it indicates partial compensation – that is, the right PFC cannot completely supplement the failing neural network, but contributes positively to performance. We propose that combining structural and diffusion brain MRI can be used to test predictions from these theories which have arisen from fMRI studies. We test these hypotheses in immediate and delayed verbal memory ability amongst 90 healthy older adults of mean age 73 years. Right hippocampus and left dorsolateral prefrontal cortex (DLPFC) volumes, and fractional anisotropy (FA) in the splenium made unique contributions to verbal memory ability in the whole group. There was no significant effect of anterior callosal white matter integrity on performance. Rather, segmented linear regression indicated that right DLPFC volume was a significantly stronger positive predictor of verbal memory for lower-scorers than higher-scorers, supporting a compensatory explanation for the differential involvement of the right frontal lobe in verbal memory tasks in older age. PMID:25241394

Frontal lobe connectivity and cognitive impairment in pediatric frontal lobe epilepsy.

PubMed

Braakman, Hilde M H; Vaessen, Maarten J; Jansen, Jacobus F A; Debeij-van Hall, Mariette H J A; de Louw, Anton; Hofman, Paul A M; Vles, Johan S H; Aldenkamp, Albert P; Backes, Walter H

2013-03-01

Cognitive impairment is frequent in children with frontal lobe epilepsy (FLE), but its etiology is unknown. With functional magnetic resonance imaging (fMRI), we have explored the relationship between brain activation, functional connectivity, and cognitive functioning in a cohort of pediatric patients with FLE and healthy controls. Thirty-two children aged 8-13 years with FLE of unknown cause and 41 healthy age-matched controls underwent neuropsychological assessment and structural and functional brain MRI. We investigated to which extent brain regions activated in response to a working memory task and assessed functional connectivity between distant brain regions. Data of patients were compared to controls, and patients were grouped as cognitively impaired or unimpaired. Children with FLE showed a global decrease in functional brain connectivity compared to healthy controls, whereas brain activation patterns in children with FLE remained relatively intact. Children with FLE complicated by cognitive impairment typically showed a decrease in frontal lobe connectivity. This decreased frontal lobe connectivity comprised both connections within the frontal lobe as well as connections from the frontal lobe to the parietal lobe, temporal lobe, cerebellum, and basal ganglia. Decreased functional frontal lobe connectivity is associated with cognitive impairment in pediatric FLE. The importance of impairment of functional integrity within the frontal lobe network, as well as its connections to distant areas, provides new insights in the etiology of the broad-range cognitive impairments in children with FLE. Wiley Periodicals, Inc. © 2012 International League Against Epilepsy.

Emerging Directions in Emotional Episodic Memory.

PubMed

Dolcos, Florin; Katsumi, Yuta; Weymar, Mathias; Moore, Matthew; Tsukiura, Takashi; Dolcos, Sanda

2017-01-01

Building upon the existing literature on emotional memory, the present review examines emerging evidence from brain imaging investigations regarding four research directions: (1) Social Emotional Memory , (2) The Role of Emotion Regulation in the Impact of Emotion on Memory , (3) The Impact of Emotion on Associative or Relational Memory , and (4) The Role of Individual Differences in Emotional Memory . Across these four domains, available evidence demonstrates that emotion- and memory-related medial temporal lobe brain regions (amygdala and hippocampus, respectively), together with prefrontal cortical regions, play a pivotal role during both encoding and retrieval of emotional episodic memories. This evidence sheds light on the neural mechanisms of emotional memories in healthy functioning, and has important implications for understanding clinical conditions that are associated with negative affective biases in encoding and retrieving emotional memories.

Emerging Directions in Emotional Episodic Memory

PubMed Central

Dolcos, Florin; Katsumi, Yuta; Weymar, Mathias; Moore, Matthew; Tsukiura, Takashi; Dolcos, Sanda

2017-01-01

Building upon the existing literature on emotional memory, the present review examines emerging evidence from brain imaging investigations regarding four research directions: (1) Social Emotional Memory, (2) The Role of Emotion Regulation in the Impact of Emotion on Memory, (3) The Impact of Emotion on Associative or Relational Memory, and (4) The Role of Individual Differences in Emotional Memory. Across these four domains, available evidence demonstrates that emotion- and memory-related medial temporal lobe brain regions (amygdala and hippocampus, respectively), together with prefrontal cortical regions, play a pivotal role during both encoding and retrieval of emotional episodic memories. This evidence sheds light on the neural mechanisms of emotional memories in healthy functioning, and has important implications for understanding clinical conditions that are associated with negative affective biases in encoding and retrieving emotional memories. PMID:29255432

Episodic memory in aspects of large-scale brain networks

PubMed Central

Jeong, Woorim; Chung, Chun Kee; Kim, June Sic

2015-01-01

Understanding human episodic memory in aspects of large-scale brain networks has become one of the central themes in neuroscience over the last decade. Traditionally, episodic memory was regarded as mostly relying on medial temporal lobe (MTL) structures. However, recent studies have suggested involvement of more widely distributed cortical network and the importance of its interactive roles in the memory process. Both direct and indirect neuro-modulations of the memory network have been tried in experimental treatments of memory disorders. In this review, we focus on the functional organization of the MTL and other neocortical areas in episodic memory. Task-related neuroimaging studies together with lesion studies suggested that specific sub-regions of the MTL are responsible for specific components of memory. However, recent studies have emphasized that connectivity within MTL structures and even their network dynamics with other cortical areas are essential in the memory process. Resting-state functional network studies also have revealed that memory function is subserved by not only the MTL system but also a distributed network, particularly the default-mode network (DMN). Furthermore, researchers have begun to investigate memory networks throughout the entire brain not restricted to the specific resting-state network (RSN). Altered patterns of functional connectivity (FC) among distributed brain regions were observed in patients with memory impairments. Recently, studies have shown that brain stimulation may impact memory through modulating functional networks, carrying future implications of a novel interventional therapy for memory impairment. PMID:26321939

Short-Term Memory Depends on Dissociable Medial Temporal Lobe Regions in Amnestic Mild Cognitive Impairment

PubMed Central

Das, Sandhitsu R.; Mancuso, Lauren; Olson, Ingrid R.; Arnold, Steven E.; Wolk, David A.

2016-01-01

Short-term memory (STM) has generally been thought to be independent of the medial temporal lobe (MTL) in contrast to long-term memory (LTM). Prodromal Alzheimer's disease (AD) is a condition in which the MTL is a major early focus of pathology and LTM is thought disproportionately affected relative to STM. However, recent studies have suggested a role for the MTL in STM, particularly hippocampus, when binding of different elements is required. Other work has suggested involvement of extrahippocampal MTL structures, particularly in STM tasks that involve item-level memory. We examined STM for individual objects, locations, and object-location conjunctions in amnestic mild cognitive impairment (MCI), often associated with prodromal AD. Relative to age-matched, cognitively normal controls, MCI patients not only displayed impairment on object-location conjunctions but were similarly impaired for non-bound objects and locations. Moreover, across all participants, these conditions displayed dissociable correlations of cortical thinning along the long axis of the MTL and associated cortical nodes of anterior and posterior MTL networks. These findings support the role of the MTL in visual STM tasks and the division of labor of MTL in support of different types of memory representations, overlapping with findings in LTM. PMID:25725042

The impact of brain-derived neurotrophic factor Val66Met polymorphism on cognition and functional brain networks in patients with intractable partial epilepsy.

PubMed

Sidhu, Meneka K; Thompson, Pamela J; Wandschneider, Britta; Foulkes, Alexandra; de Tisi, Jane; Stretton, Jason; Perona, Marina; Thom, Maria; Bonelli, Silvia B; Burdett, Jane; Williams, Elaine; Duncan, John S; Matarin, Mar

2018-06-27

Medial temporal lobe epilepsy (mTLE) is the most common refractory focal epilepsy in adults. Around 30%-40% of patients have prominent memory impairment and experience significant postoperative memory and language decline after surgical treatment. BDNF Val66Met polymorphism has also been associated with cognition and variability in structural and functional hippocampal indices in healthy controls and some patient groups. We examined whether BDNF Val66Met variation was associated with cognitive impairment in mTLE. In this study, we investigated the association of Val66Met polymorphism with cognitive performance (n = 276), postoperative cognitive change (n = 126) and fMRI activation patterns during memory encoding and language paradigms in 2 groups of patients with mTLE (n = 37 and 34). mTLE patients carrying the Met allele performed more poorly on memory tasks and showed reduced medial temporal lobe activation and reduced task-related deactivations within the default mode networks in both the fMRI memory and language tasks than Val/Val patients. Although cognitive impairment in epilepsy is the result of a complex interaction of factors, our results suggest a role of genetic factors on cognitive impairment in mTLE. © 2018 John Wiley & Sons Ltd.

Tau and β-Amyloid Are Associated with Medial Temporal Lobe Structure, Function, and Memory Encoding in Normal Aging

PubMed Central

2017-01-01

Normal aging is associated with a decline in episodic memory and also with aggregation of the β-amyloid (Aβ) and tau proteins and atrophy of medial temporal lobe (MTL) structures crucial to memory formation. Although some evidence suggests that Aβ is associated with aberrant neural activity, the relationships among these two aggregated proteins, neural function, and brain structure are poorly understood. Using in vivo human Aβ and tau imaging, we demonstrate that increased Aβ and tau are both associated with aberrant fMRI activity in the MTL during memory encoding in cognitively normal older adults. This pathological neural activity was in turn associated with worse memory performance and atrophy within the MTL. A mediation analysis revealed that the relationship with regional atrophy was explained by MTL tau. These findings broaden the concept of cognitive aging to include evidence of Alzheimer's disease-related protein aggregation as an underlying mechanism of age-related memory impairment. SIGNIFICANCE STATEMENT Alterations in episodic memory and the accumulation of Alzheimer's pathology are common in cognitively normal older adults. However, evidence of pathological effects on episodic memory has largely been limited to β-amyloid (Aβ). Because Aβ and tau often cooccur in older adults, previous research offers an incomplete understanding of the relationship between pathology and episodic memory. With the recent development of in vivo tau PET radiotracers, we show that Aβ and tau are associated with different aspects of memory encoding, leading to aberrant neural activity that is behaviorally detrimental. In addition, our results provide evidence linking Aβ- and tau-associated neural dysfunction to brain atrophy. PMID:28213439

A neurocognitive perspective on language: the declarative/procedural model.

PubMed

Ullman, M T

2001-10-01

What are the psychological, computational and neural underpinnings of language? Are these neurocognitive correlates dedicated to language? Do different parts of language depend on distinct neurocognitive systems? Here I address these and other issues that are crucial for our understanding of two fundamental language capacities: the memorization of words in the mental lexicon, and the rule-governed combination of words by the mental grammar. According to the declarative/procedural model, the mental lexicon depends on declarative memory and is rooted in the temporal lobe, whereas the mental grammar involves procedural memory and is rooted in the frontal cortex and basal ganglia. I argue that the declarative/procedural model provides a new framework for the study of lexicon and grammar.

Hippocampal contributions to recollection in retrograde and anterograde amnesia.

PubMed

Gilboa, Asaf; Winocur, Gordon; Rosenbaum, R Shayna; Poreh, Amir; Gao, Fuqiang; Black, Sandra E; Westmacott, Robyn; Moscovitch, Morris

2006-01-01

Lesions restricted to the hippocampal formation and/or extended hippocampal system (hippocampal formation, fornix, mammillary bodies, and anterior thalamic nuclei) can disrupt conscious recollection in anterograde amnesia, while leaving familiarity-based memory relatively intact. Familiarity may be supported by extra-hippocampal medial temporal lobe (MTL) structures. Within-task dissociations in recognition memory best exemplify this distinction in anterograde amnesia. The authors report for the first time comparable dissociations within recognition memory in retrograde amnesia. An amnesic patient (A.D.) with bilateral fornix and septal nuclei lesions failed to recognize details pertaining to personal past events only when recollection was required, during recognition of episodic details. His intact recognition of generic and semantic details pertaining to the same events was ascribed to intact familiarity processes. Recollective processes in the controls were reflected by asymmetrical Receiver's Operating Characteristic curves, whereas the patient's Receiver's Operating Characteristic was symmetrical, suggesting that his inferior recognition performance on episodic details was reliant on familiarity processes. Anterograde and retrograde memories were equally affected, with no temporal gradient for retrograde memories. By comparison, another amnesic person (K.C.) with extensive MTL damage (involving extra-hippocampal MTL structures in addition to hippocampal and fornix lesions) had very poor recognition and no recollection of either episodic or generic/semantic details. These data suggest that the extended hippocampal system is required to support recollection for both anterograde and retrograde memories, regardless of their age.

Dynamic imaging in mild traumatic brain injury: support for the theory of medial temporal vulnerability.

PubMed

Umile, Eric M; Sandel, M Elizabeth; Alavi, Abass; Terry, Charles M; Plotkin, Rosette C

2002-11-01

To determine whether patients with mild traumatic brain injury (TBI) and persistent postconcussive symptoms have evidence of temporal lobe injury on dynamic imaging. Case series. An academic medical center. Twenty patients with a clinical diagnosis of mild TBI and persistent postconcussive symptoms were referred for neuropsychologic evaluation and dynamic imaging. Fifteen (75%) had normal magnetic resonance imaging (MRI) and/or computed tomography (CT) scans at the time of injury. Neuropsychologic testing, positron-emission tomography (PET), and single-photon emission-computed tomography (SPECT). Temporal lobe findings on static imaging (MRI, CT) and dynamic imaging (PET, SPECT); neuropsychologic test findings on measures of verbal and visual memory. Testing documented neurobehavioral deficits in 19 patients (95%). Dynamic imaging documented abnormal findings in 18 patients (90%). Fifteen patients (75%) had temporal lobe abnormalities on PET and SPECT (primarily in medial temporal regions); abnormal findings were bilateral in 10 patients (50%) and unilateral in 5 (25%). Six patients (30%) had frontal abnormalities, and 8 (40%) had nonfrontotemporal abnormalities. Correlations between neuropsychologic testing and dynamic imaging could be established but not consistently across the whole group. Patients with mild TBI and persistent postconcussive symptoms have a high incidence of temporal lobe injury (presumably involving the hippocampus and related structures), which may explain the frequent finding of memory disorders in this population. The abnormal temporal lobe findings on PET and SPECT in humans may be analogous to the neuropathologic evidence of medial temporal injury provided by animal studies after mild TBI. Copyright 2002 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation

Longitudinal association between hippocampus atrophy and episodic-memory decline.

PubMed

Gorbach, Tetiana; Pudas, Sara; Lundquist, Anders; Orädd, Greger; Josefsson, Maria; Salami, Alireza; de Luna, Xavier; Nyberg, Lars

2017-03-01

There is marked variability in both onset and rate of episodic-memory decline in aging. Structural magnetic resonance imaging studies have revealed that the extent of age-related brain changes varies markedly across individuals. Past studies of whether regional atrophy accounts for episodic-memory decline in aging have yielded inconclusive findings. Here we related 15-year changes in episodic memory to 4-year changes in cortical and subcortical gray matter volume and in white-matter connectivity and lesions. In addition, changes in word fluency, fluid IQ (Block Design), and processing speed were estimated and related to structural brain changes. Significant negative change over time was observed for all cognitive and brain measures. A robust brain-cognition change-change association was observed for episodic-memory decline and atrophy in the hippocampus. This association was significant for older (65-80 years) but not middle-aged (55-60 years) participants and not sensitive to the assumption of ignorable attrition. Thus, these longitudinal findings highlight medial-temporal lobe system integrity as particularly crucial for maintaining episodic-memory functioning in older age. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Towards a functional organization of episodic memory in the medial temporal lobe

PubMed Central

Eichenbaum, Howard; Sauvage, Magdalena; Fortin, Norbert; Komorowski, Robert; Lipton, Paul

2011-01-01

Here we describe a model of medial temporal lobe organization in which parallel “what” and “where” processing streams converge within the hippocampus to represent events in the spatio-temporal context in which they occurred; this circuitry also mediates the retrieval of context from event cues and vice versa, which are prototypes of episodic recall. Evidence from studies in animals are reviewed in support of this model, including experiments that distinguish characteristics of episodic recollection from familiarity, neuropsychological and recording studies that have identified a key role for the hippocampus in recollection and in associating events with the context in which they occurred, and distinct roles for parahippocampal region areas in separate “what” and “where” information processing that contributes to recollective and episodic memory. PMID:21810443

Coherent concepts are computed in the anterior temporal lobes.

PubMed

Lambon Ralph, Matthew A; Sage, Karen; Jones, Roy W; Mayberry, Emily J

2010-02-09

In his Philosophical Investigations, Wittgenstein famously noted that the formation of semantic representations requires more than a simple combination of verbal and nonverbal features to generate conceptually based similarities and differences. Classical and contemporary neuroscience has tended to focus upon how different neocortical regions contribute to conceptualization through the summation of modality-specific information. The additional yet critical step of computing coherent concepts has received little attention. Some computational models of semantic memory are able to generate such concepts by the addition of modality-invariant information coded in a multidimensional semantic space. By studying patients with semantic dementia, we demonstrate that this aspect of semantic memory becomes compromised following atrophy of the anterior temporal lobes and, as a result, the patients become increasingly influenced by superficial rather than conceptual similarities.

Towards a functional organization of episodic memory in the medial temporal lobe.

PubMed

Eichenbaum, Howard; Sauvage, Magdalena; Fortin, Norbert; Komorowski, Robert; Lipton, Paul

2012-08-01

Here we describe a model of medial temporal lobe organization in which parallel "what" and "where" processing streams converge within the hippocampus to represent events in the spatio-temporal context in which they occurred; this circuitry also mediates the retrieval of context from event cues and vice versa, which are prototypes of episodic recall. Evidence from studies in animals are reviewed in support of this model, including experiments that distinguish characteristics of episodic recollection from familiarity, neuropsychological and recording studies that have identified a key role for the hippocampus in recollection and in associating events with the context in which they occurred, and distinct roles for parahippocampal region areas in separate "what" and "where" information processing that contributes to recollective and episodic memory. Copyright © 2011 Elsevier Ltd. All rights reserved.

Basal ganglia and Dopamine Contributions to Probabilistic Category Learning

PubMed Central

Shohamy, D.; Myers, C.E.; Kalanithi, J.; Gluck, M.A.

2009-01-01

Studies of the medial temporal lobe and basal ganglia memory systems have recently been extended towards understanding the neural systems contributing to category learning. The basal ganglia, in particular, have been linked to probabilistic category learning in humans. A separate parallel literature in systems neuroscience has emerged, indicating a role for the basal ganglia and related dopamine inputs in reward prediction and feedback processing. Here, we review behavioral, neuropsychological, functional neuroimaging, and computational studies of basal ganglia and dopamine contributions to learning in humans. Collectively, these studies implicate the basal ganglia in incremental, feedback-based learning that involves integrating information across multiple experiences. The medial temporal lobes, by contrast, contribute to rapid encoding of relations between stimuli and support flexible generalization of learning to novel contexts and stimuli. By breaking down our understanding of the cognitive and neural mechanisms contributing to different aspects of learning, recent studies are providing insight into how, and when, these different processes support learning, how they may interact with each other, and the consequence of different forms of learning for the representation of knowledge. PMID:18061261

Practice guideline summary: Use of fMRI in the presurgical evaluation of patients with epilepsy

PubMed Central

Szaflarski, Jerzy P.; Gloss, David; Binder, Jeffrey R.; Gaillard, William D.; Golby, Alexandra J.; Holland, Scott K.; Ojemann, Jeffrey; Spencer, David C.; Swanson, Sara J.; French, Jacqueline A.; Theodore, William H.

2017-01-01

Objective: To assess the diagnostic accuracy and prognostic value of functional MRI (fMRI) in determining lateralization and predicting postsurgical language and memory outcomes. Methods: An 11-member panel evaluated and rated available evidence according to the 2004 American Academy of Neurology process. At least 2 panelists reviewed the full text of 172 articles and selected 37 for data extraction. Case reports, reports with <15 cases, meta-analyses, and editorials were excluded. Results and recommendations: The use of fMRI may be considered an option for lateralizing language functions in place of intracarotid amobarbital procedure (IAP) in patients with medial temporal lobe epilepsy (MTLE; Level C), temporal epilepsy in general (Level C), or extratemporal epilepsy (Level C). For patients with temporal neocortical epilepsy or temporal tumors, the evidence is insufficient (Level U). fMRI may be considered to predict postsurgical language deficits after anterior temporal lobe resection (Level C). The use of fMRI may be considered for lateralizing memory functions in place of IAP in patients with MTLE (Level C) but is of unclear utility in other epilepsy types (Level U). fMRI of verbal memory or language encoding should be considered for predicting verbal memory outcome (Level B). fMRI using nonverbal memory encoding may be considered for predicting visuospatial memory outcomes (Level C). Presurgical fMRI could be an adequate alternative to IAP memory testing for predicting verbal memory outcome (Level C). Clinicians should carefully advise patients of the risks and benefits of fMRI vs IAP during discussions concerning choice of specific modality in each case. PMID:28077494

Salience Network and Parahippocampal Dopamine Dysfunction in Memory-Impaired Parkinson Disease

PubMed Central

Christopher, Leigh; Duff-Canning, Sarah; Koshimori, Yuko; Segura, Barbara; Boileau, Isabelle; Chen, Robert; Lang, Anthony E.; Houle, Sylvain; Rusjan, Pablo; Strafella, Antonio P.

2016-01-01

Objective Patients with Parkinson disease (PD) and mild cognitive impairment (MCI) are vulnerable to dementia and frequently experience memory deficits. This could be the result of dopamine dysfunction in corticostriatal networks (salience, central executive networks, and striatum) and/or the medial temporal lobe. Our aim was to investigate whether dopamine dysfunction in these regions contributes to memory impairment in PD. Methods We used positron emission tomography imaging to compare D2 receptor availability in the cortex and striatal (limbic and associative) dopamine neuron integrity in 4 groups: memory-impaired PD (amnestic MCI; n=9), PD with nonamnestic MCI (n=10), PD without MCI (n=11), and healthy controls (n=14). Subjects were administered a full neuropsychological test battery for cognitive performance. Results Memory-impaired patients demonstrated more significant reductions in D2 receptor binding in the salience network (insular cortex and anterior cingulate cortex [ACC] and the right parahippocampal gyrus [PHG]) compared to healthy controls and patients with no MCI. They also presented reductions in the right insula and right ACC compared to nonamnestic MCI patients. D2 levels were correlated with memory performance in the right PHG and left insula of amnestic patients and with executive performance in the bilateral insula and left ACC of all MCI patients. Associative striatal dopamine denervation was significant in all PD patients. Interpretation Dopaminergic differences in the salience network and the medial temporal lobe contribute to memory impairment in PD. Furthermore, these findings indicate the vulnerability of the salience network in PD and its potential role in memory and executive dysfunction. PMID:25448687

Semantic dementia Brazilian study of nineteen cases

PubMed Central

Senaha, Mirna Lie Hosogi; Caramelli, Paulo; Porto, Claudia Sellitto; Nitrini, Ricardo

2007-01-01

The term semantic dementia was devised by Snowden et al. in 1989 and nowadays, the semantic dementia syndrome is recognized as one of the clinical forms of frontotemporal lobar degeneration (FTLD) and is characterized by a language semantic disturbance associated to non-verbal semantic memory impairment. Objectives The aim of this study was to describe a Brazilian sample of 19 semantic dementia cases, emphasizing the clinical characteristics important for differential diagnosis of this syndrome. Methods Nineteen cases with semantic dementia were evaluated between 1999 and 2007. All patients were submitted to neurological evaluation, neuroimaging exams and cognitive, language and semantic memory evaluation. Results All patients presented fluent spontaneous speech, preservation of syntactic and phonological aspects of the language, word-finding difficulty, semantic paraphasias, word comprehension impairment, low performance in visual confrontation naming tasks, impairment on tests of non-verbal semantic memory and preservation of autobiographical memory and visuospatial skills. Regarding radiological investigations, temporal lobe atrophy and/or hypoperfusion were found in all patients. Conclusions The cognitive, linguistic and of neuroimaging data in our case series corroborate other studies showing that semantic dementia constitutes a syndrome with well defined clinical characteristics associated to temporal lobe atrophy. PMID:29213413

Temporal Lobe Seizure

MedlinePlus

... period of confusion and difficulty speaking Inability to recall what occurred during the seizure Unawareness of having ... of the brain that's responsible for learning and memory (hippocampus) to shrink. Brain cell loss in this ...

Progressive biparietal atrophy: an atypical presentation of Alzheimer's disease.

PubMed Central

Ross, S J; Graham, N; Stuart-Green, L; Prins, M; Xuereb, J; Patterson, K; Hodges, J R

1996-01-01

OBJECTIVES: To define the clinical, neuropsychological, and radiological features of bilateral parietal lobe atrophy. METHODS: Four patients underwent a comprehensive longitudinal neuropsychological assessment, as well as MRI and HMPAO-SPECT. RESULTS: The consistent findings in the patients were early visuospatial problems, agraphia of a predominantly peripheral (or apraxic) type, and difficulty with bimanual tasks, all of which outweighted deficits in memory and language until later in the course of the illness. As the disease progressed, impairments in the phonological aspects of language and in auditory-verbal short term memory were often striking, perhaps reflecting spread from the parietal lobe to perisylvian language areas. Three patients went on to develop a global dementia and fulfilled the criteria for a clinical diagnosis of probable Alzheimer's disease; the fourth patient has only recently been identified. Neuroimaging disclosed bilateral parietal lobe atrophy (MRI) and hypoperfusion (SPECT), which was out of proportion to that seen elsewhere in the brain. One patient has died and had pathologically confirmed Alzheimer's disease with particular concentration in both superior parietal lobes. CONCLUSIONS: Bilateral biparietal atrophy is a recognisable clinical syndrome which can be the presenting feature of Alzheimer's disease. Although the label "posterior cortical atrophy" has been applied to such cases, review of the medical literature suggests that this broad rubric actually consists of two main clinical syndromes with features reflecting involvement of the occipitotemporal (ventral) and biparietal (dorsal) cortical areas respectively. Images PMID:8890778

Impairments in Precision, Rather than Spatial Strategy, Characterize Performance on the Virtual Morris Water Maze: A Case Study

PubMed Central

Kolarik, Branden S.; Shahlaie, Kiarash; Hassan, Abdul; Borders, Alyssa A.; Kaufman, Kyle C.; Gurkoff, Gene; Yonelinas, Andy P.; Ekstrom, Arne D.

2015-01-01

Damage to the medial temporal lobes produces profound amnesia, greatly impairing the ability of patients to learn about new associations and events. While studies in rodents suggest a strong link between damage to the hippocampus and the ability to navigate using distal landmarks in a spatial environment, the connection between navigation and memory in humans remains less clear. Past studies on human navigation have provided mixed findings about whether patients with damage to the medial temporal lobes can successfully acquire and navigate new spatial environments, possibly due, in part, to issues related to patient demographics and characterization of medial temporal lobe damage. Here, we report findings from a young, high functioning patient who suffered severe medial temporal lobe damage. Although the patient is densely amnestic, her ability to acquire and utilize new, but coarse, spatial “maps” appears largely intact. Specifically, a novel computational analysis focused on the precision of her spatial search revealed a significant deficit in spatial precision rather than spatial search strategy. These findings argue that an intact hippocampus in humans is not necessary for representing multiple external landmarks during spatial navigation of new environments. We suggest instead that the human hippocampus may store and represent complex high-resolution bindings of features in the environment as part of a larger role in perception, memory, and navigation. PMID:26593960

Expression and distribution of octopus gonadotropin-releasing hormone in the central nervous system and peripheral organs of the octopus (Octopus vulgaris) by in situ hybridization and immunohistochemistry.

PubMed

Iwakoshi-Ukena, Eiko; Ukena, Kazuyoshi; Takuwa-Kuroda, Kyoko; Kanda, Atshuhiro; Tsutsui, Kazuyoshi; Minakata, Hiroyuki

2004-09-20

We recently purified a peptide with structural features similar to vertebrate gonadotropin-releasing hormone (GnRH) from the brain of Octopus vulgaris, cloned a cDNA encoding the precursor protein, and named it oct-GnRH. In the current study, we investigated the expression and distribution of oct-GnRH throughout the central nervous system (CNS) and peripheral organs of Octopus by in situ hybridization on the basis of the cDNA sequence and by immunohistochemistry using a specific antiserum against oct-GnRH. Oct-GnRH mRNA-expressing cell bodies were located in 10 of 19 lobes in the supraesophageal and subesophageal parts of the CNS. Several oct-GnRH-like immunoreactive fibers were seen in all the neuropils of the CNS lobes. The sites of oct-GnRH mRNA expression and the mature peptide distribution were consistent with each other as judged by in situ hybridization and immunohistochemistry. In addition, many immunoreactive fibers were distributed in peripheral organs such as the heart, the oviduct, and the oviducal gland. Modulatory effects of oct-GnRH on the contractions of the heart and the oviduct were demonstrated. The results suggested that, in the context of reproduction, oct-GnRH is a key peptide in the subpedunculate lobe and/or posterior olfactory lobe-optic gland-gonadal axis, an octopus analogue of the hypothalamo-hypophysial-gonadal axis. It may also act as a modulatory factor in controlling higher brain functions such as feeding, memory, movement, maturation, and autonomic functions

Hemispheric encoding/retrieval asymmetry in episodic memory: positron emission tomography findings.

PubMed Central

Tulving, E; Kapur, S; Craik, F I; Moscovitch, M; Houle, S

1994-01-01

Data are reviewed from positron emission tomography studies of encoding and retrieval processes in episodic memory. These data suggest a hemispheric encoding/retrieval asymmetry model of prefrontal involvement in encoding and retrieval of episodic memory. According to this model, the left and right prefrontal lobes are part of an extensive neuronal network that subserves episodic remembering, but the two prefrontal hemispheres play different roles. Left prefrontal cortical regions are differentially more involved in retrieval of information from semantic memory and in simultaneously encoding novel aspects of the retrieved information into episodic memory. Right prefrontal cortical regions, on the other hand, are differentially more involved in episodic memory retrieval. PMID:8134342

Behaviors induced or disrupted by complex partial seizures.

PubMed

Leung, L S; Ma, J; McLachlan, R S

2000-09-01

We reviewed the neural mechanisms underlying some postictal behaviors that are induced or disrupted by temporal lobe seizures in humans and animals. It is proposed that the psychomotor behaviors and automatisms induced by temporal lobe seizures are mediated by the nucleus accumbens. A non-convulsive hippocampal afterdischarge in rats induced an increase in locomotor activity, which was suppressed by the injection of dopamine D(2) receptor antagonist in the nucleus accumbens, and blocked by inactivation of the medial septum. In contrast, a convulsive hippocampal or amygdala seizure induced behavioral hypoactivity, perhaps by the spread of the seizure into the frontal cortex and opiate-mediated postictal depression. Mechanisms underlying postictal psychosis, memory disruption and other long-term behavioral alterations after temporal lobe seizures, are discussed. In conclusion, many of the changes of postictal behaviors observed after temporal lobe seizures in humans may be found in animals, and the basis of the behavioral change may be explained as a change in neural processing in the temporal lobe and the connecting subcortical structures.

The overall pathological status of the left hippocampus determines preoperative verbal memory performance in left mesial temporal lobe epilepsy.

PubMed

Witt, Juri-Alexander; Coras, Roland; Schramm, Johannes; Becker, Albert J; Elger, Christian E; Blümcke, Ingmar; Helmstaedter, Christoph

2014-04-01

Studies on hippocampal cell loss in epilepsy have produced diverging evidence as to which subfields are specifically related to memory. This may be due to rather small and often heterogeneous samples, or to different memory measures. Therefore, the current study examined hippocampal cell densities and memory in a large sample of patients with solely mesial temporal lobe epilepsy (mTLE), employing measures with proven sensitivity to mesiotemporal pathology. In 104 patients who had undergone epilepsy surgery for mTLE, we evaluated the role of segmental hippocampal cell loss and its underlying factor structure with regard to presurgical verbal and figural memory while controlling for side-of-surgery and hemispheric dominance. First of all, patients showed material-specific memory impairment concordant with the lateralization of epilepsy. Factor analysis of segmental cell loss revealed a single factor reflecting the overall integrity of the hippocampus. The overall pathological status of the left hippocampus correlated with verbal memory parameters (r = 0.33-0.34, P < 0.05), especially when controlling for atypical hemispheric dominance (r = 0.50-0.57, P < 0.01), and explained up to 33% of the observed variance. Further analyses revealed no superior role of a single subfield or cell loss pattern for memory performance. No systematic relations between neuronal cell densities of the right hippocampus and memory function were found, nor did left or right hippocampal pathology explain figural memory parameters. The results suggest that the overall pathological status of the left hippocampus - rather than a specific subfield pathology - is predictive for verbal memory in mTLE. The finding that figural memory parameters, although sensitive to right mTLE, were not related to neuronal cell densities of the right hippocampus, puts the left/right hippocampus verbal/nonverbal memory dichotomy into perspective. Copyright © 2013 Wiley Periodicals, Inc.

Memory binding and white matter integrity in familial Alzheimer’s disease

PubMed Central

Saarimäki, Heini; Bastin, Mark E.; Londoño, Ana C.; Pettit, Lewis; Lopera, Francisco; Della Sala, Sergio; Abrahams, Sharon

2015-01-01

Binding information in short-term and long-term memory are functions sensitive to Alzheimer’s disease. They have been found to be affected in patients who meet criteria for familial Alzheimer’s disease due to the mutation E280A of the PSEN1 gene. However, only short-term memory binding has been found to be affected in asymptomatic carriers of this mutation. The neural correlates of this dissociation are poorly understood. The present study used diffusion tensor magnetic resonance imaging to investigate whether the integrity of white matter structures could offer an account. A sample of 19 patients with familial Alzheimer’s disease, 18 asymptomatic carriers and 21 non-carrier controls underwent diffusion tensor magnetic resonance imaging, neuropsychological and memory binding assessment. The short-term memory binding task required participants to detect changes across two consecutive screens displaying arrays of shapes, colours, or shape-colour bindings. The long-term memory binding task was a Paired Associates Learning Test. Performance on these tasks were entered into regression models. Relative to controls, patients with familial Alzheimer’s disease performed poorly on both memory binding tasks. Asymptomatic carriers differed from controls only in the short-term memory binding task. White matter integrity explained poor memory binding performance only in patients with familial Alzheimer’s disease. White matter water diffusion metrics from the frontal lobe accounted for poor performance on both memory binding tasks. Dissociations were found in the genu of corpus callosum which accounted for short-term memory binding impairments and in the hippocampal part of cingulum bundle which accounted for long-term memory binding deficits. The results indicate that white matter structures in the frontal and temporal lobes are vulnerable to the early stages of familial Alzheimer’s disease and their damage is associated with impairments in two memory binding functions known to be markers for Alzheimer’s disease. PMID:25762465

Memory binding and white matter integrity in familial Alzheimer's disease.

PubMed

Parra, Mario A; Saarimäki, Heini; Bastin, Mark E; Londoño, Ana C; Pettit, Lewis; Lopera, Francisco; Della Sala, Sergio; Abrahams, Sharon

2015-05-01

Binding information in short-term and long-term memory are functions sensitive to Alzheimer's disease. They have been found to be affected in patients who meet criteria for familial Alzheimer's disease due to the mutation E280A of the PSEN1 gene. However, only short-term memory binding has been found to be affected in asymptomatic carriers of this mutation. The neural correlates of this dissociation are poorly understood. The present study used diffusion tensor magnetic resonance imaging to investigate whether the integrity of white matter structures could offer an account. A sample of 19 patients with familial Alzheimer's disease, 18 asymptomatic carriers and 21 non-carrier controls underwent diffusion tensor magnetic resonance imaging, neuropsychological and memory binding assessment. The short-term memory binding task required participants to detect changes across two consecutive screens displaying arrays of shapes, colours, or shape-colour bindings. The long-term memory binding task was a Paired Associates Learning Test. Performance on these tasks were entered into regression models. Relative to controls, patients with familial Alzheimer's disease performed poorly on both memory binding tasks. Asymptomatic carriers differed from controls only in the short-term memory binding task. White matter integrity explained poor memory binding performance only in patients with familial Alzheimer's disease. White matter water diffusion metrics from the frontal lobe accounted for poor performance on both memory binding tasks. Dissociations were found in the genu of corpus callosum which accounted for short-term memory binding impairments and in the hippocampal part of cingulum bundle which accounted for long-term memory binding deficits. The results indicate that white matter structures in the frontal and temporal lobes are vulnerable to the early stages of familial Alzheimer's disease and their damage is associated with impairments in two memory binding functions known to be markers for Alzheimer's disease. © The Author (2015). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

The neural circuit basis of learning

NASA Astrophysics Data System (ADS)

Patrick, Kaifosh William John

The astounding capacity for learning ranks among the nervous system's most impressive features. This thesis comprises studies employing varied approaches to improve understanding, at the level of neural circuits, of the brain's capacity for learning. The first part of the thesis contains investigations of hippocampal circuitry -- both theoretical work and experimental work in the mouse Mus musculus -- as a model system for declarative memory. To begin, Chapter 2 presents a theory of hippocampal memory storage and retrieval that reflects nonlinear dendritic processing within hippocampal pyramidal neurons. As a prelude to the experimental work that comprises the remainder of this part, Chapter 3 describes an open source software platform that we have developed for analysis of data acquired with in vivo Ca2+ imaging, the main experimental technique used throughout the remainder of this part of the thesis. As a first application of this technique, Chapter 4 characterizes the content of signaling at synapses between GABAergic neurons of the medial septum and interneurons in stratum oriens of hippocampal area CA1. Chapter 5 then combines these techniques with optogenetic, pharmacogenetic, and pharmacological manipulations to uncover inhibitory circuit mechanisms underlying fear learning. The second part of this thesis focuses on the cerebellum-like electrosensory lobe in the weakly electric mormyrid fish Gnathonemus petersii, as a model system for non-declarative memory. In Chapter 6, we study how short-duration EOD motor commands are recoded into a complex temporal basis in the granule cell layer, which can be used to cancel Purkinje-like cell firing to the longer duration and temporally varying EOD-driven sensory responses. In Chapter 7, we consider not only the temporal aspects of the granule cell code, but also the encoding of body position provided from proprioceptive and efference copy sources. Together these studies clarify how the cerebellum-like circuitry of the electrosensory lobe combines information of different forms and then uses this combined information to predict the complex dependence of sensory responses on body position and timing relative to electric organ discharge.

Neural correlates of reward-based spatial learning in persons with cocaine dependence.

PubMed

Tau, Gregory Z; Marsh, Rachel; Wang, Zhishun; Torres-Sanchez, Tania; Graniello, Barbara; Hao, Xuejun; Xu, Dongrong; Packard, Mark G; Duan, Yunsuo; Kangarlu, Alayar; Martinez, Diana; Peterson, Bradley S

2014-02-01

Dysfunctional learning systems are thought to be central to the pathogenesis of and impair recovery from addictions. The functioning of the brain circuits for episodic memory or learning that support goal-directed behavior has not been studied previously in persons with cocaine dependence (CD). Thirteen abstinent CD and 13 healthy participants underwent MRI scanning while performing a task that requires the use of spatial cues to navigate a virtual-reality environment and find monetary rewards, allowing the functional assessment of the brain systems for spatial learning, a form of episodic memory. Whereas both groups performed similarly on the reward-based spatial learning task, we identified disturbances in brain regions involved in learning and reward in CD participants. In particular, CD was associated with impaired functioning of medial temporal lobe (MTL), a brain region that is crucial for spatial learning (and episodic memory) with concomitant recruitment of striatum (which normally participates in stimulus-response, or habit, learning), and prefrontal cortex. CD was also associated with enhanced sensitivity of the ventral striatum to unexpected rewards but not to expected rewards earned during spatial learning. We provide evidence that spatial learning in CD is characterized by disturbances in functioning of an MTL-based system for episodic memory and a striatum-based system for stimulus-response learning and reward. We have found additional abnormalities in distributed cortical regions. Consistent with findings from animal studies, we provide the first evidence in humans describing the disruptive effects of cocaine on the coordinated functioning of multiple neural systems for learning and memory.

The declarative/procedural model of lexicon and grammar.

PubMed

Ullman, M T

2001-01-01

Our use of language depends upon two capacities: a mental lexicon of memorized words and a mental grammar of rules that underlie the sequential and hierarchical composition of lexical forms into predictably structured larger words, phrases, and sentences. The declarative/procedural model posits that the lexicon/grammar distinction in language is tied to the distinction between two well-studied brain memory systems. On this view, the memorization and use of at least simple words (those with noncompositional, that is, arbitrary form-meaning pairings) depends upon an associative memory of distributed representations that is subserved by temporal-lobe circuits previously implicated in the learning and use of fact and event knowledge. This "declarative memory" system appears to be specialized for learning arbitrarily related information (i.e., for associative binding). In contrast, the acquisition and use of grammatical rules that underlie symbol manipulation is subserved by frontal/basal-ganglia circuits previously implicated in the implicit (nonconscious) learning and expression of motor and cognitive "skills" and "habits" (e.g., from simple motor acts to skilled game playing). This "procedural" system may be specialized for computing sequences. This novel view of lexicon and grammar offers an alternative to the two main competing theoretical frameworks. It shares the perspective of traditional dual-mechanism theories in positing that the mental lexicon and a symbol-manipulating mental grammar are subserved by distinct computational components that may be linked to distinct brain structures. However, it diverges from these theories where they assume components dedicated to each of the two language capacities (that is, domain-specific) and in their common assumption that lexical memory is a rote list of items. Conversely, while it shares with single-mechanism theories the perspective that the two capacities are subserved by domain-independent computational mechanisms, it diverges from them where they link both capacities to a single associative memory system with broad anatomic distribution. The declarative/procedural model, but neither traditional dual- nor single-mechanism models, predicts double dissociations between lexicon and grammar, with associations among associative memory properties, memorized words and facts, and temporal-lobe structures, and among symbol-manipulation properties, grammatical rule products, motor skills, and frontal/basal-ganglia structures. In order to contrast lexicon and grammar while holding other factors constant, we have focused our investigations of the declarative/procedural model on morphologically complex word forms. Morphological transformations that are (largely) unproductive (e.g., in go-went, solemn-solemnity) are hypothesized to depend upon declarative memory. These have been contrasted with morphological transformations that are fully productive (e.g., in walk-walked, happy-happiness), whose computation is posited to be solely dependent upon grammatical rules subserved by the procedural system. Here evidence is presented from studies that use a range of psycholinguistic and neurolinguistic approaches with children and adults. It is argued that converging evidence from these studies supports the declarative/procedural model of lexicon and grammar.

Effects of hypoglycaemia on working memory and regional cerebral blood flow in type 1 diabetes: a randomised, crossover trial.

PubMed

Gejl, Michael; Gjedde, Albert; Brock, Birgitte; Møller, Arne; van Duinkerken, Eelco; Haahr, Hanne L; Hansen, Charlotte T; Chu, Pei-Ling; Stender-Petersen, Kirstine L; Rungby, Jørgen

2018-03-01

The aim of this randomised, crossover trial was to compare cognitive functioning and associated brain activation patterns during hypoglycaemia (plasma glucose [PG] just below 3.1 mmol/l) and euglycaemia in individuals with type 1 diabetes mellitus. In this patient-blinded, crossover study, 26 participants with type 1 diabetes mellitus attended two randomised experimental visits: one hypoglycaemic clamp (PG 2.8 ± 0.2 mmol/l, approximate duration 55 min) and one euglycaemic clamp (PG 5.5 mmol/l ± 10%). PG levels were maintained by hyperinsulinaemic glucose clamping. Cognitive functioning was assessed during hypoglycaemia and euglycaemia conditions using a modified version of the digit symbol substitution test (mDSST) and control DSST (cDSST). Simultaneously, regional cerebral blood flow (rCBF) was measured in pre-specified brain regions by six H 2 15 O-positron emission tomographies (PET) per session. Working memory was impaired during hypoglycaemia as indicated by a statistically significantly lower mDSST score (estimated treatment difference [ETD] -0.63 [95% CI -1.13, -0.14], p = 0.014) and a statistically significantly longer response time (ETD 2.86 s [7%] [95% CI 0.67, 5.05], p = 0.013) compared with euglycaemia. During hypoglycaemia, mDSST task performance was associated with increased activity in the frontal lobe regions, superior parietal lobe and thalamus, and decreased activity in the temporal lobe regions (p < 0.05). Working memory activation (mDSST - cDSST) statistically significantly increased blood flow in the striatum during hypoglycaemia (ETD 0.0374% [95% CI 0.0157, 0.0590], p = 0.002). During hypoglycaemia (mean PG 2.9 mmol/l), working memory performance was impaired. Altered performance was associated with significantly increased blood flow in the striatum, a part of the basal ganglia implicated in regulating motor functions, memory, language and emotion. NCT01789593, clinicaltrials.gov FUNDING: This study was funded by Novo Nordisk.

Overwhelming remembrance of things past: Proust portrays limbic kindling by external stimulus--literary genius can presage neurobiological patterns of puzzling behavior.

PubMed

Pontius, A A

1993-10-01

Proust detailed inexplicable behavior long before the neurobiologists Goddard and McIntyre in 1972 demonstrated that intermittent repetition of harmless stimuli can cause "kindling" of a seizure (with or without motor convulsions). Such brief seizures can occur especially in the evolutionarily old limbic system which mediates basic drives, their concomitant emotions, and certain aspects of memory. It appears that in humans the influence of specific external stimuli that revive the memory of repeated past experiences may "kindle" a transient episode of limbic overactivation. Thereupon the normal balance between the limbic and frontal lobe systems is disturbed (for a few minutes) as are normal human decision making and control of action. Linked with such a transient frontolimbic imbalance is out-of-character behavior, psychosis (hallucinations or delusions), autonomic activation, and severe distortion of affect and of action, culminating in extreme cases in a "Limbic Psychotic Trigger Reaction," as proposed by Pontius in 1981, in motiveless homicidal acts with mostly preserved consciousness and memory for the acts.

Preserved complex emotion-based learning in amnesia.

PubMed

Turnbull, Oliver H; Evans, Cathryn E Y

2006-01-01

An important role for emotion in decision-making has recently been highlighted by disruptions in problem solving abilities after lesion to the frontal lobes. Such complex decision-making skills appear to be based on a class of memory ability (emotion-based learning) that may be anatomically independent of hippocampally mediated episodic memory systems. There have long been reports of intact emotion-based learning in amnesia, arguably dating back to the classic report of Claparede. However, all such accounts relate to relatively simple patterns of emotional valence learning, rather than the more complex contingency patterns of emotional experience, which characterise everyday life. A patient, SL, who had a profound anterograde amnesia following posterior cerebral artery infarction, performed a measure of complex emotion-based learning (the Iowa Gambling Task) on three separate occasions. Despite his severe episodic memory impairment, he showed normal levels of performance on the Gambling Task, at levels comparable or better than controls-including learning that persisted across substantial periods of time (weeks). Thus, emotion-based learning systems appear able to encode, and sustain, more sophisticated patterns of valence learning than have previously been reported.

Short-term memory in olfactory network dynamics

NASA Astrophysics Data System (ADS)

Stopfer, Mark; Laurent, Gilles

1999-12-01

Neural assemblies in a number of animal species display self-organized, synchronized oscillations in response to sensory stimuli in a variety of brain areas.. In the olfactory system of insects, odour-evoked oscillatory synchronization of antennal lobe projection neurons (PNs) is superimposed on slower and stimulus-specific temporal activity patterns. Hence, each odour activates a specific and dynamic projection neuron assembly whose evolution during a stimulus is locked to the oscillation clock. Here we examine, using locusts, the changes in population dynamics of projection-neuron assemblies over repeated odour stimulations, as would occur when an animal first encounters and then repeatedly samples an odour for identification or localization. We find that the responses of these assemblies rapidly decrease in intensity, while they show a marked increase in spike time precision and inter-neuronal oscillatory coherence. Once established, this enhanced precision in the representation endures for several minutes. This change is stimulus-specific, and depends on events within the antennal lobe circuits, independent of olfactory receptor adaptation: it may thus constitute a form of sensory memory. Our results suggest that this progressive change in olfactory network dynamics serves to converge, over repeated odour samplings, on a more precise and readily classifiable odour representation, using relational information contained across neural assemblies.

Event-related brain potentials in memory: correlates of episodic, semantic and implicit memory.

PubMed

Wieser, Stephan; Wieser, Heinz Gregor

2003-06-01

To study cognitive evoked potentials, recorded from scalp EEG and foramen ovale electrodes, during activation of explicit and implicit memory. The subgroups of explicit memory, episodic and semantic memory, are looked at separately. A word-learning task was used, which has been shown to activate hippocampus in H(2)(15)O positron emission tomography studies. Subjects had to study and remember word pairs using different learning strategies: (i) associative word learning (AWL), which activates the episodic memory, (ii) deep single word encoding (DSWE), which activates the semantic memory, and (iii) shallow single word encoding (SSWE), which activates the implicit memory and serves as a baseline. The test included the 'remember/know' paradigm as a behavioural learning control. During the task condition, a 10-20 scalp EEG with additional electrodes in both temporal lobes regions was recorded from 11 healthy volunteers. In one patient with mesiotemporal lobe epilepsy, the EEG was recorded from bilateral foramen ovale electrodes directly from mesial temporal lobe structures. Event-related potentials (ERPs) were calculated off-line and visual and statistical analyses were made. Associative learning strategy produced the best memory performance and the best noetic awareness experience, whereas shallow single word encoding produced the worst performance and the smallest noetic awareness. Deep single word encoding performance was in between. ERPs differed according to the test condition, during both encoding and retrieval, from both the scalp EEG and the foramen ovale electrode recordings. Encoding showed significant differences between the shallow single word encoding (SSWE), which is mainly a function of graphical characteristics, and the other two strategies, deep single word (DSWE) and associative learning (AWL), in which there is a semantic processing of the meaning. ERPs generated by these two categories, which are both functions of explicit memory, differed as well, indicating the presence or the absence of associative binding. Retrieval showed a significant test effect between the word pairs learned by association (AWL) and the ones learned by encoding the words in isolation of each other (DSWE and SSWE). The comparison of the ERPs generated by autonoetic awareness ('remember') and noetic awareness ('know') exhibited a significant test effect as well. The results of behavioural data, in particular that of the 'remember/know' procedure, are evidence that the task paradigm was efficient in activating different kinds of memory. Associative word learning generated a high degree of autonoetic awareness, which is a result of the episodic memory, whereas both kinds of single word learning generated less. AWL, DSWE and SSWE resulted in different electrophysiological correlates, both for encoding as well as retrieval, indicating that different brain structures were activated in different temporal sequence.

Integrated Analysis of Alzheimer's Disease and Schizophrenia Dataset Revealed Different Expression Pattern in Learning and Memory.

PubMed

Li, Wen-Xing; Dai, Shao-Xing; Liu, Jia-Qian; Wang, Qian; Li, Gong-Hua; Huang, Jing-Fei

2016-01-01

Alzheimer's disease (AD) and schizophrenia (SZ) are both accompanied by impaired learning and memory functions. This study aims to explore the expression profiles of learning or memory genes between AD and SZ. We downloaded 10 AD and 10 SZ datasets from GEO-NCBI for integrated analysis. These datasets were processed using RMA algorithm and a global renormalization for all studies. Then Empirical Bayes algorithm was used to find the differentially expressed genes between patients and controls. The results showed that most of the differentially expressed genes were related to AD whereas the gene expression profile was little affected in the SZ. Furthermore, in the aspects of the number of differentially expressed genes, the fold change and the brain region, there was a great difference in the expression of learning or memory related genes between AD and SZ. In AD, the CALB1, GABRA5, and TAC1 were significantly downregulated in whole brain, frontal lobe, temporal lobe, and hippocampus. However, in SZ, only two genes CRHBP and CX3CR1 were downregulated in hippocampus, and other brain regions were not affected. The effect of these genes on learning or memory impairment has been widely studied. It was suggested that these genes may play a crucial role in AD or SZ pathogenesis. The different gene expression patterns between AD and SZ on learning and memory functions in different brain regions revealed in our study may help to understand the different mechanism between two diseases.

Accelerated long-term forgetting in resected and seizure-free temporal lobe epilepsy patients.

PubMed

Visser, M; Forn, C; Gómez-Ibáñez, A; Rosell-Negre, P; Villanueva, V; Ávila, C

2018-03-12

Episodic memory impairments caused by temporal lobe epilepsy (TLE) are well documented in the literature. Standard clinical episodic memory tests typically include a 30-min delayed recall test. However, in the past decade, it has become apparent that this standard test does not capture the full range of memory problems in TLE patients. Some patients perform well on a standard 30-min delayed recall test, but show Accelerated Long-term Forgetting (ALF) after 24 h. Although ALF has been investigated in patients with different types of epilepsy, current research on resected TLE patients is missing. In the present study, resected TLE patients were compared to a control group matched on initial learning. They showed normal performance on verbal recall after 30 min, but impairments became apparent after one week. Moreover, the significant interaction between participant group and memory test delay demonstrated that the patients indeed showed an acceleration in forgetting. Furthermore, ALF was present in both left and right resected TLE patients, which contradicts the presence of material-specific hemispheric differences in ALF. In addition, ALF was observed in seizure-free resected TLE patients, thereby demonstrating that this factor is not crucial for long-term memory deficits. The outcome shows that clinicians are likely to underestimate memory deficits in resected TLE patients and, therefore, advocates for the inclusion of ALF tests in standard clinical batteries for both pre- and post-surgery testing sessions. Copyright © 2018 Elsevier Ltd. All rights reserved.

Clinical utility of the Wechsler Memory Scale--Fourth Edition (WMS-IV) in predicting laterality of temporal lobe epilepsy among surgical candidates.

PubMed

Soble, Jason R; Eichstaedt, Katie E; Waseem, Hena; Mattingly, Michelle L; Benbadis, Selim R; Bozorg, Ali M; Vale, Fernando L; Schoenberg, Mike R

2014-12-01

This study evaluated the accuracy of the Wechsler Memory Scale--Fourth Edition (WMS-IV) in identifying functional cognitive deficits associated with seizure laterality in localization-related temporal lobe epilepsy (TLE) relative to a previously established measure, the Rey Auditory Verbal Learning Test (RAVLT). Emerging WMS-IV studies have highlighted psychometric improvements that may enhance its ability to identify lateralized memory deficits. Data from 57 patients with video-EEG-confirmed unilateral TLE who were administered the WMS-IV and RAVLT as part of a comprehensive presurgical neuropsychological evaluation for temporal resection were retrospectively reviewed. We examined the predictive accuracy of the WMS-IV not only in terms of verbal versus visual composite scores but also using individual subtests. A series of hierarchal logistic regression models were developed, including the RAVLT, WMS-IV delayed subtests (Logical Memory, Verbal Paired Associates, Designs, Visual Reproduction), and a WMS-IV verbal-visual memory difference score. Analyses showed that the RAVLT significantly predicted laterality with overall classification rates of 69.6% to 70.2%, whereas neither the individual WMS-IV subtests nor the verbal-visual memory difference score accounted for additional significant variance. Similar to previous versions of the WMS, findings cast doubt as to whether the WMS-IV offers significant incremental validity in discriminating seizure laterality in TLE beyond what can be obtained from the RAVLT. Copyright © 2014 Elsevier Inc. All rights reserved.

Neural activity in the medial temporal lobe reveals the fidelity of mental time travel.

PubMed

Kragel, James E; Morton, Neal W; Polyn, Sean M

2015-02-18

Neural circuitry in the medial temporal lobe (MTL) is critically involved in mental time travel, which involves the vivid retrieval of the details of past experience. Neuroscientific theories propose that the MTL supports memory of the past by retrieving previously encoded episodic information, as well as by reactivating a temporal code specifying the position of a particular event within an episode. However, the neural computations supporting these abilities are underspecified. To test hypotheses regarding the computational mechanisms supported by different MTL subregions during mental time travel, we developed a computational model that linked a blood oxygenation level-dependent signal to cognitive operations, allowing us to predict human performance in a memory search task. Activity in the posterior MTL, including parahippocampal cortex, reflected how strongly one reactivates the temporal context of a retrieved memory, allowing the model to predict whether the next memory will correspond to a nearby moment in the study episode. A signal in the anterior MTL, including perirhinal cortex, indicated the successful retrieval of list items, without providing information regarding temporal organization. A hippocampal signal reflected both processes, consistent with theories that this region binds item and context information together to form episodic memories. These findings provide evidence for modern theories that describe complementary roles of the hippocampus and surrounding parahippocampal and perirhinal cortices during the retrieval of episodic memories, shaping how humans revisit the past. Copyright © 2015 the authors 0270-6474/15/352914-13$15.00/0.

Paramnesic multiplication of autobiographical memory as a manifestation of interictal psychosis.

PubMed

Murai, Toshiya; Fukao, Kenjiro

2003-01-01

This report describes a male patient with temporal lobe epilepsy who developed a persistent paranoid-hallucinatory state at the age of 23. The essential feature of his delusion was that he had repeatedly lived part of his life, namely between the ages of 21 and 25 years. The patient repeatedly attempted suicide to escape the endless repetition. His paramnesia has some similarity with a déjà vu phenomenon, which is a common ictal manifestation of temporal lobe epilepsy. However, while only a sense of vague familiarity is evoked in a déjà vu phenomenon, conscious recollection is experienced during his paramnesia. We attempted to explain the pathophysiological mechanism of the patient's paramnesia in the framework of the current neurobiological theory of human memory. Copyright 2003 S. Karger AG, Basel

Focal retrograde amnesia and the episodic-semantic distinction.

PubMed

Wheeler, M A; McMillan, C T

2001-03-01

This article reports a review of focal retrograde amnesia (FRA), or the phenomenon of organically based severe memory loss restricted to retrograde, or pretraumatic, memory. Cases of FRA are classified according to the type of memory loss: episodic, semantic, or both. A few different clusters of the disorder were identified. Lesions to either the anterior temporal lobes or the posterior/visual cortex can result in an FRA that devastates retrograde episodic memory, while having smaller effects on semantic memory. A number of left-hemisphere patients have FRA confined to semantic memory. There are several additional examples of FRA following minor cerebral trauma that disrupts either episodic memory alone or both episodic and semantic memory that are not accompanied by evidence of structural brain lesions. We discuss these different profiles of FRA and their implications for the understanding of memory retrieval.

Different macaque models of cognitive aging exhibit task-dependent behavioral disparities.

PubMed

Comrie, Alison E; Gray, Daniel T; Smith, Anne C; Barnes, Carol A

2018-05-15

Deficits in cognitive functions that rely on the integrity of the frontal and temporal lobes are characteristic of normative human aging. Due to similar aging phenotypes and homologous cortical organization between nonhuman primates and humans, several species of macaque monkeys are used as models to explore brain senescence. These macaque species are typically regarded as equivalent models of cognitive aging, yet no direct comparisons have been made to support this assumption. Here we used adult and aged rhesus and bonnet macaques (Macaca mulatta and Macaca radiata) to characterize the effect of age on acquisition and retention of information across delays in a battery of behavioral tasks that rely on prefrontal cortex and medial temporal lobe networks. The cognitive functions that were tested include visuospatial short-term memory, object recognition memory, and object-reward association memory. In general, bonnet macaques at all ages outperformed rhesus macaques on tasks thought to rely primarily on the prefrontal cortex, and were more resilient to age-related deficits in these behaviors. On the other hand, both species were comparably impaired by age on tasks thought to preferentially engage the medial temporal lobe. Together, these results suggest that rhesus and bonnet macaques are not equivalent models of cognitive aging and highlight the value of cross-species comparisons. These observations should enable improved design and interpretation of future experiments aimed at understanding changes in cognition across the lifespan. Copyright © 2018 Elsevier B.V. All rights reserved.

Face-name association task reveals memory networks in patients with left and right hippocampal sclerosis.

PubMed

Klamer, Silke; Milian, Monika; Erb, Michael; Rona, Sabine; Lerche, Holger; Ethofer, Thomas

2017-01-01

We aimed to identify reorganization processes of episodic memory networks in patients with left and right temporal lobe epilepsy (TLE) due to hippocampal sclerosis as well as their relations to neuropsychological memory performance. We investigated 28 healthy subjects, 12 patients with left TLE (LTLE) and 9 patients with right TLE (RTLE) with hippocampal sclerosis by means of functional magnetic resonance imaging (fMRI) using a face-name association task, which combines verbal and non-verbal memory functions. Regions-of-interest (ROIs) were defined based on the group results of the healthy subjects. In each ROI, fMRI activations were compared across groups and correlated with verbal and non-verbal memory scores. The face-name association task yielded activations in bilateral hippocampus (HC), left inferior frontal gyrus (IFG), left superior frontal gyrus (SFG), left superior temporal gyrus, bilateral angular gyrus (AG), bilateral medial prefrontal cortex and right anterior temporal lobe (ATL). LTLE patients demonstrated significantly less activation in the left HC and left SFG, whereas RTLE patients showed significantly less activation in the HC bilaterally, the left SFG and right AG. Verbal memory scores correlated with activations in the left and right HC, left SFG and right ATL and non-verbal memory scores with fMRI activations in the left and right HC and left SFG. The face-name association task can be employed to examine functional alterations of hippocampal activation during encoding of both verbal and non-verbal material in one fMRI paradigm. Further, the left SFG seems to be a convergence region for encoding of verbal and non-verbal material.

Hippocampal Network Modularity Is Associated With Relational Memory Dysfunction in Schizophrenia.

PubMed

Avery, Suzanne N; Rogers, Baxter P; Heckers, Stephan

2018-05-01

Functional dysconnectivity has been proposed as a major pathophysiological mechanism for cognitive dysfunction in schizophrenia. The hippocampus is a focal point of dysconnectivity in schizophrenia, with decreased hippocampal functional connectivity contributing to the marked memory deficits observed in patients. Normal memory function relies on the interaction of complex corticohippocampal networks. However, only recent technological advances have enabled the large-scale exploration of functional networks with accuracy and precision. We investigated the modularity of hippocampal resting-state functional networks in a sample of 45 patients with schizophrenia spectrum disorders and 38 healthy control subjects. Modularity was calculated for two distinct functional networks: a core hippocampal-medial temporal lobe cortex network and an extended hippocampal-cortical network. As hippocampal function differs along its longitudinal axis, follow-up analyses examined anterior and posterior networks separately. To explore effects of resting network function on behavior, we tested associations between modularity and relational memory ability. Age, sex, handedness, and parental education were similar between groups. Network modularity was lower in schizophrenia patients, especially in the posterior hippocampal network. Schizophrenia patients also showed markedly lower relational memory ability compared with control subjects. We found a distinct brain-behavior relationship in schizophrenia that differed from control subjects by network and anterior/posterior division-while relational memory in control subjects was associated with anterior hippocampal-cortical modularity, schizophrenia patients showed an association with posterior hippocampal-medial temporal lobe cortex network modularity. Our findings support a model of abnormal resting-state corticohippocampal network coherence in schizophrenia, which may contribute to relational memory deficits. Copyright © 2018 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Levels of processing with free and cued recall and unilateral temporal lobe epilepsy.

PubMed

Lespinet-Najib, Véronique; N'Kaoua, Bernard; Sauzéon, Hélène; Bresson, Christel; Rougier, Alain; Claverie, Bernard

2004-04-01

This study investigates the role of the temporal lobes in levels-of-processing tasks (phonetic and semantic encoding) according to the nature of recall tasks (free and cued recall). These tasks were administered to 48 patients with unilateral temporal epilepsy (right "RTLE"=24; left "LTLE"=24) and a normal group (n=24). The results indicated that LTLE patients were impaired for semantic processing (free and cued recall) and for phonetic processing (free and cued recall), while for RTLE patients deficits appeared in free recall with semantic processing. It is suggested that the left temporal lobe is involved in all aspects of verbal memory, and that the right temporal lobe is specialized in semantic processing. Moreover, our data seem to indicate that RTLE patients present a retrieval processing impairment (semantic condition), whereas the LTLE group is characterized by encoding difficulties in the phonetic and semantic condition.

Dementia of frontal lobe type.

PubMed Central

Neary, D; Snowden, J S; Northen, B; Goulding, P

1988-01-01

A significant proportion of patients with presenile dementia due to primary cerebral atrophy do not have Alzheimer's disease. One form of non-Alzheimer dementia may be designated as dementia of frontal lobe type (DFT), on the basis of a characteristic neuropsychological picture suggestive of frontal lobe disorder, confirmed by findings on single photon emission tomography. The case histories of seven patients exemplify the disorder: a presentation of social misconduct and personality change, unconcern and disinhibition, in the presence of physical well-being and few neurological signs. Assessment revealed economic and concrete speech with verbal stereotypes, variable memory impairment, and marked abnormalities on tasks sensitive to frontal lobe function. Visuo-spatial disorder was invariably absent. Comparisons of DFT and Alzheimer patients revealed qualitative differences in clinical presentation, neurological signs, profile of psychological disability, electroencephalography, single photon emission tomography and demography. DFT, which may represent forms of Pick's disease, may be more common than is often recognised. PMID:3258902

Atypical language representation in children with intractable temporal lobe epilepsy.

PubMed

Maulisova, Alice; Korman, Brandon; Rey, Gustavo; Bernal, Byron; Duchowny, Michael; Niederlova, Marketa; Krsek, Pavel; Novak, Vilem

2016-05-01

This study evaluated language organization in children with intractable epilepsy caused by temporal lobe focal cortical dysplasia (FCD) alone or dual pathology (temporal lobe FCD and hippocampal sclerosis, HS). We analyzed clinical, neurological, fMRI, neuropsychological, and histopathologic data in 46 pediatric patients with temporal lobe lesions who underwent excisional epilepsy surgery. The frequency of atypical language representation was similar in both groups, but children with dual pathology were more likely to be left-handed. Atypical receptive language cortex correlated with lower intellectual capacity, verbal abstract conceptualization, receptive language abilities, verbal working memory, and a history of status epilepticus but did not correlate with higher seizure frequency or early seizure onset. Histopathologic substrate had only a minor influence on neuropsychological status. Greater verbal comprehension deficits were noted in children with atypical receptive language representation, a risk factor for cognitive morbidity. Copyright © 2016 Elsevier Inc. All rights reserved.

Cognitive Function and Heat Shock Protein 70 in Children With Temporal Lobe Epilepsy.

PubMed

Oraby, Azza M; Raouf, Ehab R Abdol; El-Saied, Mostafa M; Abou-Khadra, Maha K; Helal, Suzette I; Hashish, Adel F

2017-01-01

We conducted the present study to examine cognitive function and serum heat shock protein 70 levels among children with temporal lobe epilepsy. The Stanford-Binet Intelligence Test was carried out to examine cognitive function in 30 children with temporal lobe epilepsy and 30 controls. Serum heat shock protein 70 levels were determined with an enzyme-linked immunosorbent assay. The epilepsy group had significantly lower cognitive function testing scores and significantly higher serum heat shock protein 70 levels than the control group; there were significant negative correlations between serum heat shock protein 70 levels and short-term memory and composite scores. Children with uncontrolled seizures had significantly lower verbal reasoning scores and significantly higher serum heat shock protein 70 levels than children with controlled seizures. Children with temporal lobe epilepsy have cognitive dysfunction and elevated levels of serum heat shock protein 70, which may be considered a stress biomarker.

The medial temporal lobes distinguish between within-item and item-context relations during autobiographical memory retrieval.

PubMed

Sheldon, Signy; Levine, Brian

2015-12-01

During autobiographical memory retrieval, the medial temporal lobes (MTL) relate together multiple event elements, including object (within-item relations) and context (item-context relations) information, to create a cohesive memory. There is consistent support for a functional specialization within the MTL according to these relational processes, much of which comes from recognition memory experiments. In this study, we compared brain activation patterns associated with retrieving within-item relations (i.e., associating conceptual and sensory-perceptual object features) and item-context relations (i.e., spatial relations among objects) with respect to naturalistic autobiographical retrieval. We developed a novel paradigm that cued participants to retrieve information about past autobiographical events, non-episodic within-item relations, and non-episodic item-context relations with the perceptuomotor aspects of retrieval equated across these conditions. We used multivariate analysis techniques to extract common and distinct patterns of activity among these conditions within the MTL and across the whole brain, both in terms of spatial and temporal patterns of activity. The anterior MTL (perirhinal cortex and anterior hippocampus) was preferentially recruited for generating within-item relations later in retrieval whereas the posterior MTL (posterior parahippocampal cortex and posterior hippocampus) was preferentially recruited for generating item-context relations across the retrieval phase. These findings provide novel evidence for functional specialization within the MTL with respect to naturalistic memory retrieval. © 2015 Wiley Periodicals, Inc.

Short-Term Memory Depends on Dissociable Medial Temporal Lobe Regions in Amnestic Mild Cognitive Impairment.

PubMed

Das, Sandhitsu R; Mancuso, Lauren; Olson, Ingrid R; Arnold, Steven E; Wolk, David A

2016-05-01

Short-term memory (STM) has generally been thought to be independent of the medial temporal lobe (MTL) in contrast to long-term memory (LTM). Prodromal Alzheimer's disease (AD) is a condition in which the MTL is a major early focus of pathology and LTM is thought disproportionately affected relative to STM. However, recent studies have suggested a role for the MTL in STM, particularly hippocampus, when binding of different elements is required. Other work has suggested involvement of extrahippocampal MTL structures, particularly in STM tasks that involve item-level memory. We examined STM for individual objects, locations, and object-location conjunctions in amnestic mild cognitive impairment (MCI), often associated with prodromal AD. Relative to age-matched, cognitively normal controls, MCI patients not only displayed impairment on object-location conjunctions but were similarly impaired for non-bound objects and locations. Moreover, across all participants, these conditions displayed dissociable correlations of cortical thinning along the long axis of the MTL and associated cortical nodes of anterior and posterior MTL networks. These findings support the role of the MTL in visual STM tasks and the division of labor of MTL in support of different types of memory representations, overlapping with findings in LTM. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Practice guideline summary: Use of fMRI in the presurgical evaluation of patients with epilepsy: Report of the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology.

PubMed

Szaflarski, Jerzy P; Gloss, David; Binder, Jeffrey R; Gaillard, William D; Golby, Alexandra J; Holland, Scott K; Ojemann, Jeffrey; Spencer, David C; Swanson, Sara J; French, Jacqueline A; Theodore, William H

2017-01-24

To assess the diagnostic accuracy and prognostic value of functional MRI (fMRI) in determining lateralization and predicting postsurgical language and memory outcomes. An 11-member panel evaluated and rated available evidence according to the 2004 American Academy of Neurology process. At least 2 panelists reviewed the full text of 172 articles and selected 37 for data extraction. Case reports, reports with <15 cases, meta-analyses, and editorials were excluded. The use of fMRI may be considered an option for lateralizing language functions in place of intracarotid amobarbital procedure (IAP) in patients with medial temporal lobe epilepsy (MTLE; Level C), temporal epilepsy in general (Level C), or extratemporal epilepsy (Level C). For patients with temporal neocortical epilepsy or temporal tumors, the evidence is insufficient (Level U). fMRI may be considered to predict postsurgical language deficits after anterior temporal lobe resection (Level C). The use of fMRI may be considered for lateralizing memory functions in place of IAP in patients with MTLE (Level C) but is of unclear utility in other epilepsy types (Level U). fMRI of verbal memory or language encoding should be considered for predicting verbal memory outcome (Level B). fMRI using nonverbal memory encoding may be considered for predicting visuospatial memory outcomes (Level C). Presurgical fMRI could be an adequate alternative to IAP memory testing for predicting verbal memory outcome (Level C). Clinicians should carefully advise patients of the risks and benefits of fMRI vs IAP during discussions concerning choice of specific modality in each case. © 2017 American Academy of Neurology.

Preserved memory abilities in thalamic amnesia.

PubMed

Nichelli, P; Bahmanian-Behbahani, G; Gentilini, M; Vecchi, A

1988-12-01

The pattern of preserved learning abilities is described in a severely amnesic patient after bilateral thalamic infarction. Experimental findings cannot be accounted for both by the view that only episodic memory is impaired in amnesia, while semantic memory is spared, and by the theory that what is spared in amnesia is procedural learning contrasted with impaired declarative memory. In agreement with Warrington and Weiskrantz (1982), diencephalic amnesia is considered to be a disconnection syndrome between the frontal and temporal lobes. The conditions for showing spared and impaired memory in amnesics are specified on the basis of the performance of the patient and of the data available in the literature. This allows us to derive practical suggestions for programmes aimed at remediation of memory defects.

Risk factors for spatial memory impairment in patients with temporal lobe epilepsy.

PubMed

Amlerova, Jana; Laczo, Jan; Vlcek, Kamil; Javurkova, Alena; Andel, Ross; Marusic, Petr

2013-01-01

At present, the risk factors for world-centered (allocentric) navigation impairment in patients with temporal lobe epilepsy (TLE) are not known. There is some evidence on the importance of the right hippocampus but other clinical features have not been investigated yet. In this study, we used an experimental human equivalent to the Morris water maze to examine spatial navigation performance in patients with drug-refractory unilateral TLE. We included 47 left-hemisphere speech dominant patients (25 right sided; 22 left sided). The aim of our study was to identify clinical and demographic characteristics of TLE patients who performed poorly in allocentric spatial memory tests. Our results demonstrate that poor spatial navigation is significantly associated with younger age at epilepsy onset, longer disease duration, and lower intelligence level. Allocentric navigation in TLE patients was impaired irrespective of epilepsy lateralization. Good and poor navigators did not differ in their age, gender, or preoperative/postoperative status. This study provides evidence on risk factors that increase the likelihood of allocentric navigation impairment in TLE patients. The results indicate that not only temporal lobe dysfunction itself but also low general cognitive abilities may contribute to the navigation impairment. Copyright © 2012 Elsevier Inc. All rights reserved.

Divergent Task Performance in Older Adults: Declarative Memory or Creative Potential?

PubMed Central

Leon, Susan A; Altmann, Lori JP; Abrams, Lise; Rothi, Leslie J Gonzalez; Heilman, Kenneth M

2016-01-01

Divergent thinking is the ability to produce a range of responses or solutions and is an element of creative processing. Divergent thinking requires disengagement, the ability to associate between words or ideas, and the production of responses. Lesion and imaging studies have shown frontal-lobe involvement for these activities, and frontal lobe function is highly dependent on white matter pathways. Normal aging often results in deficits in functions controlled by the frontal lobes as well as decrements in white matter connectivity. The objectives of this study were to compare non time-constrained tasks of verbal divergent processing in young adults (YAs) and older adults (OAs) and correlate performance with tasks of working memory, language ability, and disengagement/inhibition. Participants were 30 YAs and 30 OAs. Contrary to the a priori hypothesis, OAs produced significantly more unique responses than YAs, although total fluency was not significantly different. Correlational analyses examining the groups together and separately revealed a number of differences suggesting that the groups were utilizing different underlying cognitive abilities to complete these tasks. The authors propose that the primary factor resulting in higher uniqueness scores for the OAs was a greater wealth of experience as well as longer exposure to language use. PMID:28446859

Music training improves verbal but not visual memory: cross-sectional and longitudinal explorations in children.

PubMed

Ho, Yim-Chi; Cheung, Mei-Chun; Chan, Agnes S

2003-07-01

The hypothesis that music training can improve verbal memory was tested in children. The results showed that children with music training demonstrated better verbal but not visual memory than did their counterparts without such training. When these children were followed up after a year, those who had begun or continued music training demonstrated significant verbal memory improvement. Students who discontinued the training did not show any improvement. Contrary to the differences in verbal memory between the groups, their changes in visual memory were not significantly different. Consistent with previous findings for adults (A. S. Chan, Y. Ho, & M. Cheung, 1998), the results suggest that music training systematically affects memory processing in accordance with possible neuroanatomical modifications in the left temporal lobe.

Direct Exploration of the Role of the Ventral Anterior Temporal Lobe in Semantic Memory: Cortical Stimulation and Local Field Potential Evidence From Subdural Grid Electrodes

PubMed Central

Shimotake, Akihiro; Matsumoto, Riki; Ueno, Taiji; Kunieda, Takeharu; Saito, Satoru; Hoffman, Paul; Kikuchi, Takayuki; Fukuyama, Hidenao; Miyamoto, Susumu; Takahashi, Ryosuke; Ikeda, Akio; Lambon Ralph, Matthew A.

2015-01-01

Semantic memory is a crucial higher cortical function that codes the meaning of objects and words, and when impaired after neurological damage, patients are left with significant disability. Investigations of semantic dementia have implicated the anterior temporal lobe (ATL) region, in general, as crucial for multimodal semantic memory. The potentially crucial role of the ventral ATL subregion has been emphasized by recent functional neuroimaging studies, but the necessity of this precise area has not been selectively tested. The implantation of subdural electrode grids over this subregion, for the presurgical assessment of patients with partial epilepsy or brain tumor, offers the dual yet rare opportunities to record cortical local field potentials while participants complete semantic tasks and to stimulate the functionally identified regions in the same participants to evaluate the necessity of these areas in semantic processing. Across 6 patients, and utilizing a variety of semantic assessments, we evaluated and confirmed that the anterior fusiform/inferior temporal gyrus is crucial in multimodal, receptive, and expressive, semantic processing. PMID:25491206

False memory for context activates the parahippocampal cortex.

PubMed

Karanian, Jessica M; Slotnick, Scott D

2014-01-01

Previous studies have reported greater activity in the parahippocampal cortex during true memory than false memory, which has been interpreted as reflecting greater sensory processing during true memory. However, in these studies, sensory detail and contextual information were confounded. In the present fMRI study, we employed a novel paradigm to dissociate these factors. During encoding, abstract shapes were presented in one of two contexts (i.e., moving or stationary). During retrieval, participants classified shapes as previously "moving" or "stationary." Critically, contextual processing was relatively greater during false memory ("moving" responses to stationary items), while sensory processing was relatively greater during true memory ("moving" responses to moving items). Within the medial temporal lobe, false memory versus true memory produced greater activity in the parahippocampal cortex, whereas true memory versus false memory produced greater activity in the hippocampus. The present results indicate that the parahippocampal cortex mediates contextual processing rather than sensory processing.

Lateralising value of experiential hallucinations in temporal lobe epilepsy.

PubMed

Heydrich, Lukas; Marillier, Guillaume; Evans, Nathan; Blanke, Olaf; Seeck, Margitta

2015-11-01

Ever since John Hughlings Jackson first described the so-called 'dreamy state' during temporal lobe epilepsy, that is, the sense of an abnormal familiarity (déjà vu) or vivid memory-like hallucinations from the past (experiential hallucinations), these phenomena have been studied and repeatedly linked to mesial temporal lobe structures. However, little is known about the lateralising value of either déjà vu or experiential hallucinations. We analysed a sample of 28 patients with intractable focal epilepsy suffering from either déjà vu or experiential hallucinations. All the patients underwent thorough presurgical examination, including MRI, positron emission tomography, single-photon emission CT, EEG and neuropsychological examination. While déjà vu was due to right or left mesial temporal lobe epilepsy, experiential hallucinations were strongly lateralised to the left mesial temporal lobe. Moreover, there was a significant effect for interictal language deficits being more frequent in patients suffering from experiential hallucinations. These results suggest a lateralising value for experiential hallucinations to the left temporal lobe. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Component Neural Systems for the Creation of Emotional Memories during Free Viewing of a Complex, Real-World Event

PubMed Central

Botzung, Anne; LaBar, Kevin S.; Kragel, Philip; Miles, Amanda; Rubin, David C.

2010-01-01

To investigate the neural systems that contribute to the formation of complex, self-relevant emotional memories, dedicated fans of rival college basketball teams watched a competitive game while undergoing functional magnetic resonance imaging (fMRI). During a subsequent recognition memory task, participants were shown video clips depicting plays of the game, stemming either from previously-viewed game segments (targets) or from non-viewed portions of the same game (foils). After an old–new judgment, participants provided emotional valence and intensity ratings of the clips. A data driven approach was first used to decompose the fMRI signal acquired during free viewing of the game into spatially independent components. Correlations were then calculated between the identified components and post-scanning emotion ratings for successfully encoded targets. Two components were correlated with intensity ratings, including temporal lobe regions implicated in memory and emotional functions, such as the hippocampus and amygdala, as well as a midline fronto-cingulo-parietal network implicated in social cognition and self-relevant processing. These data were supported by a general linear model analysis, which revealed additional valence effects in fronto-striatal-insular regions when plays were divided into positive and negative events according to the fan's perspective. Overall, these findings contribute to our understanding of how emotional factors impact distributed neural systems to successfully encode dynamic, personally-relevant event sequences. PMID:20508750

Retrieval Demands Adaptively Change Striatal Old/New Signals and Boost Subsequent Long-Term Memory.

PubMed

Herweg, Nora A; Sommer, Tobias; Bunzeck, Nico

2018-01-17

The striatum is a central part of the dopaminergic mesolimbic system and contributes both to the encoding and retrieval of long-term memories. In this regard, the co-occurrence of striatal novelty and retrieval success effects in independent studies underlines the structure's double duty and suggests dynamic contextual adaptation. To test this hypothesis and further investigate the underlying mechanisms of encoding and retrieval dynamics, human subjects viewed pre-familiarized scene images intermixed with new scenes and classified them as indoor versus outdoor (encoding task) or old versus new (retrieval task), while fMRI and eye tracking data were recorded. Subsequently, subjects performed a final recognition task. As hypothesized, striatal activity and pupil size reflected task-conditional salience of old and new stimuli, but, unexpectedly, this effect was not reflected in the substantia nigra and ventral tegmental area (SN/VTA), medial temporal lobe, or subsequent memory performance. Instead, subsequent memory generally benefitted from retrieval, an effect possibly driven by task difficulty and activity in a network including different parts of the striatum and SN/VTA. Our findings extend memory models of encoding and retrieval dynamics by pinpointing a specific contextual factor that differentially modulates the functional properties of the mesolimbic system. SIGNIFICANCE STATEMENT The mesolimbic system is involved in the encoding and retrieval of information but it is unclear how these two processes are achieved within the same network of brain regions. In particular, memory retrieval and novelty encoding were considered in independent studies, implying that novelty (new > old) and retrieval success (old > new) effects may co-occur in the striatum. Here, we used a common framework implicating the striatum, but not other parts of the mesolimbic system, in tracking context-dependent salience of old and new information. The current study, therefore, paves the way for a more comprehensive understanding of the functional properties of the mesolimbic system during memory encoding and retrieval. Copyright © 2018 the authors 0270-6474/18/380745-10$15.00/0.

Semantic amnesia without dementia: documentation of a case.

PubMed

Rusconi, M L; Zago, S; Basso, A

1997-06-01

We described the case of a patient affected by a progressive semantic memory disorder associated with prevalent temporal lobe atrophy. This deficit seems to be "pure" in the sense that it has not been found to overlap with other cognitive deficits (intellectual, linguistic, perceptual, visuo-spatial etc.) for a long time. Furthermore, despite his impaired semantic knowledge, the autobiographical memory of the patient was largely intact. This case therefore represents a form of "semantic amnesia" without dementia, and supports the hypothesis that there is a partial distinction between "semantic" and "episodic" memory.

Functional Magnetic Resonance Imaging of Working Memory and Executive Dysfunction in Systemic Lupus Erythematosus and Antiphospholipid Antibody-Positive Patients.

PubMed

Kozora, E; Uluğ, A M; Erkan, D; Vo, A; Filley, C M; Ramon, G; Burleson, A; Zimmerman, R; Lockshin, M D

2016-11-01

Standardized cognitive tests and functional magnetic resonance imaging (fMRI) studies of systemic lupus erythematosus (SLE) patients demonstrate deficits in working memory and executive function. These neurobehavioral abnormalities are not well studied in antiphospholipid syndrome, which may occur independently of or together with SLE. This study compares an fMRI paradigm involving motor skills, working memory, and executive function in SLE patients without antiphospholipid antibody (aPL) (the SLE group), aPL-positive non-SLE patients (the aPL-positive group), and controls. Brain MRI, fMRI, and standardized cognitive assessment results were obtained from 20 SLE, 20 aPL-positive, and 10 healthy female subjects with no history of neuropsychiatric abnormality. Analysis of fMRI data showed no differences in performance across groups on bilateral motor tasks. When analysis of variance was used, significant group differences were found in 2 executive function tasks (word generation and word rhyming) and in a working memory task (N-Back). Patients positive for aPL demonstrated higher activation in bilateral frontal, temporal, and parietal cortices compared to controls during working memory and executive function tasks. SLE patients also demonstrated bilateral frontal and temporal activation during working memory and executive function tasks. Compared to controls, both aPL-positive and SLE patients had elevated cortical activation, primarily in the frontal lobes, during tasks involving working memory and executive function. These findings are consistent with cortical overactivation as a compensatory mechanism for early white matter neuropathology in these disorders. © 2016, American College of Rheumatology.

Early deficits in spatial memory and theta rhythm in experimental temporal lobe epilepsy.

PubMed

Chauvière, Laetitia; Rafrafi, Nadia; Thinus-Blanc, Catherine; Bartolomei, Fabrice; Esclapez, Monique; Bernard, Christophe

2009-04-29

Patients with temporal lobe epilepsy (TLE), the most common form of epilepsy in adults, often display cognitive deficits. The time course and underlying mechanisms of cognitive decline remain unknown during epileptogenesis (the process leading to epilepsy). Using the rat pilocarpine model of TLE, we performed a longitudinal study to assess spatial and nonspatial cognitive performance during epileptogenesis. In parallel, we monitored interictal-like activity (ILA) in the hippocampal CA1 region, as well as theta oscillations, a brain rhythm central to numerous cognitive processes. Here, we report that spatial memory was altered soon after pilocarpine-induced status epilepticus, i.e., already during the seizure-free, latent period. Spatial deficits correlated with a decrease in the power of theta oscillations but not with the frequency of ILA. Spatial deficits persisted when animals had spontaneous seizures (chronic stage) without further modification. In contrast, nonspatial memory performances remained unaffected throughout. We conclude that the reorganization of hippocampal circuitry that immediately follows the initial insult can affect theta oscillation mechanisms, in turn, resulting in deficits in hippocampus-dependent memory tasks. These deficits may be dissociated from the process that leads to epilepsy itself but could instead constitute, as ILA, early markers in at-risk patients and/or provide beneficial therapeutic targets.

The immediate and short-term effects of bilateral intrahippocampal depth electrodes on verbal memory.

PubMed

Helmstaedter, Christoph; Gielen, Gerrit H; Witt, Juri-Alexander

2018-06-01

In contrast to previous studies, Ljung et al. provide evidence of permanent cognitive consequences of bilateral intrahippocampal depth electrodes for verbal memory in patients who were not operated or operated in the right temporal lobe. Stimulated by this, we provide historical confirmatory and supplementary evidence of the detrimental effect of bilateral depth electrodes implanted along the longitudinal axis of the hippocampus on verbal learning and especially on delayed verbal memory and recognition performance. This is demonstrated in 31 patients with memory assessments before implantation, after explantation, and 3 months later after left/right temporal lobe surgery. After surgery, significant recovery from postimplantation impairment is found in right temporal patients. Left temporal resection patients stay on the level seen after implantation and do not recover. Surgery, however, has its own effects in addition to the implantation. Intracranial electrodes for electroencephalographic monitoring or electrical stimulation are commonly and increasingly used for diagnosis or treatment in pharmacoresistant epilepsies. Thus, the monitoring of invasive stereotactic approaches is recommended to find safe procedures for the patients. In response to the findings, we restricted indications and used different implantation schemes, different trajectories, and targets to minimize the risk of additional damage. Wiley Periodicals, Inc. © 2018 International League Against Epilepsy.

An fMRI comparison of neural activity associated with recognition of familiar melodies in younger and older adults

PubMed Central

Sikka, Ritu; Cuddy, Lola L.; Johnsrude, Ingrid S.; Vanstone, Ashley D.

2015-01-01

Several studies of semantic memory in non-musical domains involving recognition of items from long-term memory have shown an age-related shift from the medial temporal lobe structures to the frontal lobe. However, the effects of aging on musical semantic memory remain unexamined. We compared activation associated with recognition of familiar melodies in younger and older adults. Recognition follows successful retrieval from the musical lexicon that comprises a lifetime of learned musical phrases. We used the sparse-sampling technique in fMRI to determine the neural correlates of melody recognition by comparing activation when listening to familiar vs. unfamiliar melodies, and to identify age differences. Recognition-related cortical activation was detected in the right superior temporal, bilateral inferior and superior frontal, left middle orbitofrontal, bilateral precentral, and left supramarginal gyri. Region-of-interest analysis showed greater activation for younger adults in the left superior temporal gyrus and for older adults in the left superior frontal, left angular, and bilateral superior parietal regions. Our study provides powerful evidence for these musical memory networks due to a large sample (N = 40) that includes older adults. This study is the first to investigate the neural basis of melody recognition in older adults and to compare the findings to younger adults. PMID:26500480

Collateral brain damage, a potential source of cognitive impairment after selective surgery for control of mesial temporal lobe epilepsy.

PubMed

Helmstaedter, C; Van Roost, D; Clusmann, H; Urbach, H; Elger, C E; Schramm, J

2004-02-01

Highly selective epilepsy surgery in temporal lobe epilepsy is intended to achieve seizure freedom at a lower cognitive risk than standard en bloc resections, but bears the risk of collateral cortical damage resulting from the surgical approach. To investigate cortical damage associated with selective amygdalo-hippocampectomy (SAH). 34 epileptic patients were evaluated. They were randomly assigned to SAH using either a sylvian (9 left/10 right) or a transcortical surgical approach (5 left/10 right). Postoperative MRI signal intensity changes adjacent to the approach were correlated with performance changes in serial word and design list learning. Losses in verbal learning and recognition memory were positively related to signal intensity changes, independent of the side of the resection, the surgical approach, or the extent of the mesial resection. Losses in consolidation/retrieval (memory) were greater after left sided surgery. Losses in design learning were related to right sided surgery and signal intensity changes. Seizure outcome (85% seizure-free) did not differ depending on the side or type of surgery. Collateral damage to cortical tissues adjacent to the surgical approach contributes to postoperative verbal and figural memory outcome after SAH. Controlling for collateral damage may clarify the controversial memory outcomes after SAH reported by different surgical centres.

The impact of left and right intracranial tumors on picture and word recognition memory.

PubMed

Goldstein, Bram; Armstrong, Carol L; Modestino, Edward; Ledakis, George; John, Cameron; Hunter, Jill V

2004-02-01

This study investigated the effects of left and right intracranial tumors on picture and word recognition memory. We hypothesized that left hemispheric (LH) patients would exhibit greater word recognition memory impairment than right hemispheric (RH) patients, with no significant hemispheric group picture recognition memory differences. The LH patient group obtained a significantly slower mean picture recognition reaction time than the RH group. The LH group had a higher proportion of tumors extending into the temporal lobes, possibly accounting for their greater pictorial processing impairments. Dual coding and enhanced visual imagery may have contributed to the patient groups' similar performance on the remainder of the measures.

Limbic encephalitis associated with systemic lupus erythematosus.

PubMed

Kano, O; Arasaki, K; Ikeda, K; Aoyagi, J; Shiraishi, H; Motomura, M; Iwasaki, Y

2009-12-01

A 34-year-old woman with systemic lupus erythematosus (SLE) presented with general fatigue, seizures and memory loss. Magnetic resonance imaging of the brain showed a high signal area in the mesial temporal lobe bilaterally. Computed tomography scan of the chest and abdomen and ultrasound of pelvis detected no malignancy and tumour marker, antibodies to antineuronal antibodies (anti-Hu, anti-Ta and anti-Ma) and antibodies to voltage-gated potassium channels were all negative. The present case is limbic encephalitis (LE) associated with SLE and the pathogenesis may include autoimmunity shared. Our experience indicates that the immunologic spectrum of LE will expand to include additional immune mechanisms.

Behavioral evidence suggestive of frontal lobe pathology in the amnesic H.M.

PubMed

Winter, William

2018-06-01

From the earliest published reports, Henry Gustav Molaison-who until his death in 2008 was known simply by his initials H.M.-was characterized as having a profound anterograde amnesia subsequent to mid temporal lobe resection, and that this amnestic condition was uncomplicated by other cognitive or behavioral impairments. Post-mortem neuropathological examination has detected-in addition to the expected temporal lobe lesions-previously unreported frontal lobe and white matter pathology, inviting questions concerning the behavioral and cognitive consequences that might result from such lesions. The purpose of this article is to recount published descriptions of a range of anomalous behaviors by H.M. that can not be explained by the memory impairments typically associated with anterograde amnesia, to counter previous claims that these behaviors are attributable to amygdalar damage, and to advance the interpretation that these behaviors are instead consistent with well-documented effects of frontal lobe pathology. Transcripts of interviews with H.M. which feature disjointed, often contradictory, and arguably confabulatory responses are presented in support of this argument. Copyright © 2018 Elsevier Inc. All rights reserved.

Are the dimensions of submarine lobe systems independent of allogenic factors?

NASA Astrophysics Data System (ADS)

Prélat, A.; Covault, J. A.; Hodgson, D. M.; Fildani, A.; Flint, S. S.

2010-05-01

Submarine lobe dimensions from six different systems are compared: 1) the exhumed Permian Fan 3 lobe complex of the Tanqua Karoo, South Africa; 2) the modern Amazon fan channel-mouth lobe complex, offshore Brazil; 3) a portion of the modern distal Zaïre fan, offshore Angola / Congo; 4) a Pleistocene fan of the Kutai Basin, subsurface offshore Indonesia; 5) the modern Golo system, offshore east Corsica, France; and 6) a lobe complex deposited in the shallow subsurface, offshore Nigeria. These six systems have significantly different source-to-sink configurations (shelf dimension and slope topography), sediment supply characteristics (calibre and rate), tectonic settings, (palaeo) latitude, and delivery systems. Despite these differences, the lobe deposits share similar geometric and dimensional characteristics. Lobes are grouped into two distinct populations of geometries that can be related to basin-floor topography. The first population corresponds to areally extensive but thin lobes (average width 14 km × length 35 km × thickness 12 m) that were deposited onto low relief basin floor areas, like the Tanqua Karoo, the Amazon and the Zaïre systems. The second population corresponds to areally smaller but thicker lobes (average width 5 km × length 8 km × thickness 30 m) that were deposited into settings with higher amplitude of relief, like in the Corsican trough, the Kutai basin, and offshore Nigeria. Basin floor topography confining the lobes can be very subtle, and only occur on one side of the system. The two populations of lobe types, however, share similar volumes, in the order of 1 or 2 km3. The largest lobes are observed in the Zaïre fan, where the average lobe volume reaches 3.3 km3 and the smallest lobes are observed in the Corsican trough where the average lobe volume is 0.4 km3. This variation in lobe volume is minor when compared to the variation observed in present-day up-dip drainage systems, which provide sediment to the deep-water depositional systems and their lobes. This suggests that there is a limit to the total volume of sediment that individual lobes can reach before they shift to a new locus of deposition. In otherwords, big systems do not build big lobes, rather more lobes per unit time. Indeed, in the Amazon and the Zaïre systems, lobe life span is estimated to be 600 and 1450 years, respectively, whereas in the Corsican Golo system, lobe life span is ~ 10 times longer, around 10 to 14 × 103 years. A fundamental control on lobe volume is the propensity for flows to find the lowest topography. We postulate that a fundamental control on all distributive systems is the ratio of lobe thickness to feeder channel depth. The surface gradient from the feeder channel base and lobe top will tend to reduce through time as a lobe builds. This is not sustainable, and when a steeper lateral gradient is present a new depositional low will be used for flows to fill.

Memory in aged mice is rescued by enhanced expression of the GluN2B subunit of the NMDA receptor

PubMed Central

Brim, B. L.; Haskell, R.; Awedikian, R.; Ellinwood, N.M.; Jin, L.; Kumar, A.; Foster, T.C.; Magnusson, K.

2012-01-01

The GluN2B subunit of the N-methyl-D-aspartate (NMDA) receptor shows age-related declines in expression across the frontal cortex and hippocampus. This decline is strongly correlated to age-related memory declines. This study was designed to determine if increasing GluN2B subunit expression in the frontal lobe or hippocampus would improve memory in aged mice. Mice were injected bilaterally with either the GluN2B vector, containing cDNA specific for the GluN2B subunit and enhanced Green Fluorescent Protein (eGFP); a control vector or vehicle. Spatial memory, cognitive flexibility, and associative memory were assessed using the Morris water maze. Aged mice, with increased GluN2B subunit expression, exhibited improved long-term spatial memory, comparable to young mice. However, memory was rescued on different days in the Morris water maze; early for hippocampal GluN2B subunit enrichment and later for the frontal lobe. A higher concentration of the GluN2B antagonist, Ro 25-6981, was required to impair long-term spatial memory in aged mice with enhanced GluN2B expression, as compared to aged controls, suggesting there was an increase in the number of GluN2B-containing NMDA receptors. In addition, hippocampal slices from aged mice with increased GluN2B subunit expression exhibited enhanced NMDA receptor-mediated excitatory post-synaptic potentials (EPSP). Treatment with Ro 25-6981 showed that a greater proportion of the NMDA receptor-mediated EPSP was due to the GluN2B subunit in these animals, as compared to aged controls. These results suggest that increasing the production of the GluN2B subunit in aged animals enhances memory and synaptic transmission. Therapies that enhance GluN2B subunit expression within the aged brain may be useful for ameliorating age-related memory declines. PMID:23103326

Impact of hippocampal subfield histopathology in episodic memory impairment in mesial temporal lobe epilepsy and hippocampal sclerosis.

PubMed

Comper, Sandra Mara; Jardim, Anaclara Prada; Corso, Jeana Torres; Gaça, Larissa Botelho; Noffs, Maria Helena Silva; Lancellotti, Carmen Lúcia Penteado; Cavalheiro, Esper Abrão; Centeno, Ricardo Silva; Yacubian, Elza Márcia Targas

2017-10-01

The objective of the study was to analyze preoperative visual and verbal episodic memories in a homogeneous series of patients with mesial temporal lobe epilepsy (MTLE) and unilateral hippocampal sclerosis (HS) submitted to corticoamygdalohippocampectomy and its association with neuronal cell density of each hippocampal subfield. The hippocampi of 72 right-handed patients were collected and prepared for histopathological examination. Hippocampal sclerosis patterns were determined, and neuronal cell density was calculated. Preoperatively, two verbal and two visual memory tests (immediate and delayed recalls) were applied, and patients were divided into two groups, left and right MTLE (36/36). There were no statistical differences between groups regarding demographic and clinical data. Cornu Ammonis 4 (CA4) neuronal density was significantly lower in the right hippocampus compared with the left (p=0.048). The groups with HS presented different memory performance - the right HS were worse in visual memory test [Complex Rey Figure, immediate (p=0.001) and delayed (p=0.009)], but better in one verbal task [RAVLT delayed (p=0.005)]. Multiple regression analysis suggested that the verbal memory performance of the group with left HS was explained by CA1 neuronal density since both tasks were significantly influenced by CA1 [Logical Memory immediate recall (p=0.050) and Logical Memory and RAVLT delayed recalls (p=0.004 and p=0.001, respectively)]. For patients with right HS, both CA1 subfield integrity (p=0.006) and epilepsy duration (p=0.012) explained Complex Rey Figure immediate recall performance. Ultimately, epilepsy duration also explained the performance in the Complex Rey Figure delayed recall (p<0.001). Cornu Ammonis 1 (CA1) hippocampal subfield was related to immediate and delayed recalls of verbal memory tests in left HS, while CA1 and epilepsy duration were associated with visual memory performance in patients with right HS. Copyright © 2017 Elsevier Inc. All rights reserved.

Multiple systems of category learning.

PubMed

Smith, Edward E; Grossman, Murray

2008-01-01

We review neuropsychological and neuroimaging evidence for the existence of three qualitatively different categorization systems. These categorization systems are themselves based on three distinct memory systems: working memory (WM), explicit long-term memory (explicit LTM), and implicit long-term memory (implicit LTM). We first contrast categorization based on WM with that based on explicit LTM, where the former typically involves applying rules to a test item and the latter involves determining the similarity between stored exemplars or prototypes and a test item. Neuroimaging studies show differences between brain activity in normal participants as a function of whether they are instructed to categorize novel test items by rule or by similarity to known category members. Rule instructions typically lead to more activation in frontal or parietal areas, associated with WM and selective attention, whereas similarity instructions may activate parietal areas associated with the integration of perceptual features. Studies with neurological patients in the same paradigms provide converging evidence, e.g., patients with Alzheimer's disease, who have damage in prefrontal regions, are more impaired with rule than similarity instructions. Our second contrast is between categorization based on explicit LTM with that based on implicit LTM. Neuropsychological studies with patients with medial-temporal lobe damage show that patients are impaired on tasks requiring explicit LTM, but perform relatively normally on an implicit categorization task. Neuroimaging studies provide converging evidence: whereas explicit categorization is mediated by activation in numerous frontal and parietal areas, implicit categorization is mediated by a deactivation in posterior cortex.

Estimating Information Processing in a Memory System: The Utility of Meta-analytic Methods for Genetics.

PubMed

Yildizoglu, Tugce; Weislogel, Jan-Marek; Mohammad, Farhan; Chan, Edwin S-Y; Assam, Pryseley N; Claridge-Chang, Adam

2015-12-01

Genetic studies in Drosophila reveal that olfactory memory relies on a brain structure called the mushroom body. The mainstream view is that each of the three lobes of the mushroom body play specialized roles in short-term aversive olfactory memory, but a number of studies have made divergent conclusions based on their varying experimental findings. Like many fields, neurogenetics uses null hypothesis significance testing for data analysis. Critics of significance testing claim that this method promotes discrepancies by using arbitrary thresholds (α) to apply reject/accept dichotomies to continuous data, which is not reflective of the biological reality of quantitative phenotypes. We explored using estimation statistics, an alternative data analysis framework, to examine published fly short-term memory data. Systematic review was used to identify behavioral experiments examining the physiological basis of olfactory memory and meta-analytic approaches were applied to assess the role of lobular specialization. Multivariate meta-regression models revealed that short-term memory lobular specialization is not supported by the data; it identified the cellular extent of a transgenic driver as the major predictor of its effect on short-term memory. These findings demonstrate that effect sizes, meta-analysis, meta-regression, hierarchical models and estimation methods in general can be successfully harnessed to identify knowledge gaps, synthesize divergent results, accommodate heterogeneous experimental design and quantify genetic mechanisms.

Semantic memory and frontal executive function during transient global amnesia.

PubMed

Hodges, J R

1994-05-01

To assess semantic memory and frontal executive function, two patients underwent neuropsychological testing during transient global amnesia (TGA) and after an interval of 6-8 weeks. In spite of a profound deficit in anterograde verbal and non-verbal memory, semantic memory was normal, as judged by category fluency measures, picture naming, and picture-word and picture-picture matching, and reading ability was normal. Similarly, there were no deficits on a number of tests known to be sensitive to frontal executive dysfunction. A hexamethylpropyleneamine-oxime (HMPAO) single photon emission CT (SPECT) scan, obtained on one patient 24 hours post-TGA, showed focal left temporal lobe hypoperfusion which had resolved three months later. The observed dissociation between episodic and semantic memory is discussed in the light of contemporary cognitive theories of memory organisation.

The effects of valence and arousal on the neural activity leading to subsequent memory.

PubMed

Mickley Steinmetz, Katherine R; Kensinger, Elizabeth A

2009-11-01

This study examined how valence and arousal affect the processes linked to subsequent memory for emotional information. While undergoing an fMRI scan, participants viewed neutral pictures and emotional pictures varying by valence and arousal. After the scan, participants performed a recognition test. Subsequent memory for negative or high arousal information was associated with occipital and temporal activity, whereas memory for positive or low arousal information was associated with frontal activity. Regression analyses confirmed that for negative or high arousal items, temporal lobe activity was the strongest predictor of later memory whereas for positive or low arousal items, frontal activity corresponded most strongly with later memory. These results suggest that the types of encoding processes relating to memory (e.g., sensory vs. elaborative processing) can differ based on the affective qualities of emotional information.

The effects of valence and arousal on the neural activity leading to subsequent memory

PubMed Central

Mickley Steinmetz, Katherine R.; Kensinger, Elizabeth A.

2010-01-01

This study examined how valence and arousal affect the processes linked to subsequent memory for emotional information. While undergoing an fMRI scan, participants viewed neutral pictures and emotional pictures varying by valence and arousal. After the scan, participants performed a recognition test. Subsequent memory for negative or high arousal information was associated with occipital and temporal activity, while memory for positive or low arousal information was associated with frontal activity. Regression analyses confirmed that for negative or high arousal items, temporal lobe activity was the strongest predictor of later memory whereas for positive or low arousal items, frontal activity corresponded most strongly with later memory. These results suggest that the types of encoding processes relating to memory (e.g., sensory vs. elaborative processing) can differ based on the affective qualities of emotional information. PMID:19674398

Functional imaging of semantic memory predicts postoperative episodic memory functions in chronic temporal lobe epilepsy.

PubMed

Köylü, Bülent; Walser, Gerald; Ischebeck, Anja; Ortler, Martin; Benke, Thomas

2008-08-05

Medial temporal (MTL) structures have crucial functions in episodic (EM), but also in semantic memory (SM) processing. Preoperative functional magnetic resonance imaging (fMRI) activity within the MTL is increasingly used to predict post-surgical memory capacities. Based on the hypothesis that EM and SM memory functions are both hosted by the MTL the present study wanted to explore the relationship between SM related activations in the MTL as assessed before and the capacity of EM functions after surgery. Patients with chronic unilateral left (n=14) and right (n=12) temporal lobe epilepsy (TLE) performed a standard word list learning test pre- and postoperatively, and a fMRI procedure before the operation using a semantic decision task. SM processing caused significant bilateral MTL activations in both patient groups. While right TLE patients showed asymmetry of fMRI activation with more activation in the left MTL, left TLE patients had almost equal activation in both MTL regions. Contrasting left TLE versus right TLE patients revealed greater activity within the right MTL, whereas no significant difference was observed for the reverse contrast. Greater effect size in the MTL region ipsilateral to the seizure focus was significantly and positively correlated with preoperative EM abilities. Greater effect size in the contralateral MTL was correlated with better postoperative verbal EM, especially in left TLE patients. These results suggest that functional imaging of SM tasks may be useful to predict postoperative verbal memory in TLE. They also advocate a common neuroanatomical basis for SM and EM processes in the MTL.

Medial Temporal Lobe Damage Causes Deficits in Episodic Memory and Episodic Future Thinking Not Attributable to Deficits in Narrative Construction

PubMed Central

Race, Elizabeth; Keane, Margaret M.; Verfaellie, Mieke

2015-01-01

The medial temporal lobe (MTL) makes critical contributions to episodic memory, but its contributions to episodic future thinking remain a matter of debate. By one view, imagining future events relies on MTL mechanisms that also support memory for past events. Alternatively, it has recently been suggested that future thinking is independent of MTL-mediated processes and can be supported by regions outside the MTL. The current study investigated the nature and necessity of MTL involvement in imagining the future and tested the novel hypothesis that the MTL contributes to future thinking by supporting online binding processes related to narrative construction. Human amnesic patients with well-characterized MTL damage and healthy controls constructed narratives about (a) future events, (b) past events, and (c) visually-presented pictures. While all three tasks place similar demands on narrative construction, only the past and future conditions require memory/future thinking to mentally generate relevant narrative information. Patients produced impoverished descriptions of both past and future events but were unimpaired at producing detailed picture narratives. In addition, future-thinking performance positively correlated with episodic memory performance but did not correlate with picture narrative performance. Finally, future-thinking impairments were present when MTL lesions were restricted to the hippocampus and did not depend on the presence of neural damage outside the MTL. These results indicate that the ability to generate and maintain a detailed narrative is preserved in amnesia and suggest that a common MTL mechanism supports both episodic memory and episodic future thinking. PMID:21753003

Medial temporal lobe damage causes deficits in episodic memory and episodic future thinking not attributable to deficits in narrative construction.

PubMed

Race, Elizabeth; Keane, Margaret M; Verfaellie, Mieke

2011-07-13

The medial temporal lobe (MTL) makes critical contributions to episodic memory, but its contributions to episodic future thinking remain a matter of debate. By one view, imagining future events relies on MTL mechanisms that also support memory for past events. Alternatively, it has recently been suggested that future thinking is independent of MTL-mediated processes and can be supported by regions outside the MTL. The current study investigated the nature and necessity of MTL involvement in imagining the future and tested the novel hypothesis that the MTL contributes to future thinking by supporting online binding processes related to narrative construction. Human amnesic patients with well characterized MTL damage and healthy controls constructed narratives about (1) future events, (2) past events, and (3) visually presented pictures. While all three tasks place similar demands on narrative construction, only the past and future conditions require memory/future thinking to mentally generate relevant narrative information. Patients produced impoverished descriptions of both past and future events but were unimpaired at producing detailed picture narratives. In addition, future-thinking performance positively correlated with episodic memory performance but did not correlate with picture narrative performance. Finally, future-thinking impairments were present when MTL lesions were restricted to the hippocampus and did not depend on the presence of neural damage outside the MTL. These results indicate that the ability to generate and maintain a detailed narrative is preserved in amnesia and suggest that a common MTL mechanism supports both episodic memory and episodic future thinking.

Effects of hemisphere speech dominance and seizure focus on patterns of behavioral response errors for three types of stimuli.

PubMed

Rausch, R; MacDonald, K

1997-03-01

We used a protocol consisting of a continuous presentation of stimuli with associated response requests during an intracarotid sodium amobarbital procedure (IAP) to study the effects of hemisphere injected (speech dominant vs. nondominant) and seizure focus (left temporal lobe vs. right temporal lobe) on the pattern of behavioral response errors for three types of visual stimuli (pictures of common objects, words, and abstract forms). Injection of the left speech dominant hemisphere compared to the right nondominant hemisphere increased overall errors and affected the pattern of behavioral errors. The presence of a seizure focus in the contralateral hemisphere increased overall errors, particularly for the right temporal lobe seizure patients, but did not affect the pattern of behavioral errors. Left hemisphere injections disrupted both naming and reading responses at a rate similar to that of matching-to-sample performance. Also, a short-term memory deficit was observed with all three stimuli. Long-term memory testing following the left hemisphere injection indicated that only for pictures of common objects were there fewer errors during the early postinjection period than for the later long-term memory testing. Therefore, despite the inability to respond to picture stimuli, picture items, but not words or forms, could be sufficiently encoded for later recall. In contrast, right hemisphere injections resulted in few errors, with a pattern suggesting a mild general cognitive decrease. A selective weakness in learning unfamiliar forms was found. Our findings indicate that different patterns of behavioral deficits occur following the left vs. right hemisphere injections, with selective patterns specific to stimulus type.

Neurotoxic lesions of ventrolateral prefrontal cortex impair object-in-place scene memory

PubMed Central

Wilson, Charles R E; Gaffan, David; Mitchell, Anna S; Baxter, Mark G

2007-01-01

Disconnection of the frontal lobe from the inferotemporal cortex produces deficits in a number of cognitive tasks that require the application of memory-dependent rules to visual stimuli. The specific regions of frontal cortex that interact with the temporal lobe in performance of these tasks remain undefined. One capacity that is impaired by frontal–temporal disconnection is rapid learning of new object-in-place scene problems, in which visual discriminations between two small typographic characters are learned in the context of different visually complex scenes. In the present study, we examined whether neurotoxic lesions of ventrolateral prefrontal cortex in one hemisphere, combined with ablation of inferior temporal cortex in the contralateral hemisphere, would impair learning of new object-in-place scene problems. Male macaque monkeys learned 10 or 20 new object-in-place problems in each daily test session. Unilateral neurotoxic lesions of ventrolateral prefrontal cortex produced by multiple injections of a mixture of ibotenate and N-methyl-d-aspartate did not affect performance. However, when disconnection from inferotemporal cortex was completed by ablating this region contralateral to the neurotoxic prefrontal lesion, new learning was substantially impaired. Sham disconnection (injecting saline instead of neurotoxin contralateral to the inferotemporal lesion) did not affect performance. These findings support two conclusions: first, that the ventrolateral prefrontal cortex is a critical area within the frontal lobe for scene memory; and second, the effects of ablations of prefrontal cortex can be confidently attributed to the loss of cell bodies within the prefrontal cortex rather than to interruption of fibres of passage through the lesioned area. PMID:17445247

Neuropsychological and SPECT scan findings during and after transient global amnesia: evidence for the differential impairment of remote episodic memory.

PubMed

Evans, J; Wilson, B; Wraight, E P; Hodges, J R

1993-11-01

A patient had neuropsychological testing during, and at two days and seven weeks after a transient global amnesia (TGA) attack. During the attack she exhibited a characteristically profound anterograde amnesia but a limited remote memory loss; the most striking impairment was a deficit in personal episodic memory revealed by her performance on the Autobiographical Memory Interview. Personal and general semantic information was less impaired although there were indications of a temporal gradient in the impairment. When tested after the attack, she demonstrated normal anterograde and retrograde memory. A SPECT scan performed during TGA showed a focal reduction in cerebral perfusion in the postero-medial temporal lobes bilaterally which had resolved after seven weeks.

Storage and executive processes in the frontal lobes.

PubMed

Smith, E E; Jonides, J

1999-03-12

The human frontal cortex helps mediate working memory, a system that is used for temporary storage and manipulation of information and that is involved in many higher cognitive functions. Working memory includes two components: short-term storage (on the order of seconds) and executive processes that operate on the contents of storage. Recently, these two components have been investigated in functional neuroimaging studies. Studies of storage indicate that different frontal regions are activated for different kinds of information: storage for verbal materials activates Broca's area and left-hemisphere supplementary and premotor areas; storage of spatial information activates the right-hemisphere premotor cortex; and storage of object information activates other areas of the prefrontal cortex. Two of the fundamental executive processes are selective attention and task management. Both processes activate the anterior cingulate and dorsolateral prefrontal cortex.

Neuropsychological functioning in children with temporal lobe epilepsy and hippocampal atrophy without mesial temporal sclerosis: a distinct clinical entity?

PubMed

Schmidt, Charlotte S M; Lassonde, Maryse; Gagnon, Louise; Sauerwein, Catherine H; Carmant, Lionel; Major, Philippe; Paquette, Natacha; Lepore, Franco; Gallagher, Anne

2015-03-01

Unilateral hippocampal atrophy (HA) is considered as a precursor of mesial temporal sclerosis (MTS) in some patients with temporal lobe epilepsy. However, in other cases, it has been suggested that HA without MTS may constitute a distinct epileptic entity. Hippocampal atrophy without MTS was defined as HA without T2-weighted hyperintensity, loss of internal architecture, or associated lesion seen on the MRI data. To date, no study has focused on the cognitive pattern of children with epilepsy with HA without MTS. The objectives of the present study were to characterize the cognitive profile of these children and to investigate the presence (or the absence) of material-specific memory deficits in these young patients, as found in patients with MTS. Toward this end, 16 young patients with epilepsy with either left or right HA without MTS completed a set of neuropsychological tests, assessing overall intelligence, verbal memory and nonverbal memory, and some aspects of attention and executive functions. Results showed normal intellectual functioning without specific memory deficits in these patients. Furthermore, comparison between patients with left HA and patients with right HA failed to reveal a material-specific lateralized memory pattern. Instead, attention and executive functions were found to be impaired in most patients. These results suggest that HA may constitute a distinct epileptic entity, and this information may help health-care providers initiate appropriate and timely interventions. Copyright © 2014 Elsevier Inc. All rights reserved.

A new method for assessing the impact of medial temporal lobe amnesia on the characteristics of generated autobiographical events.

PubMed

Lenton-Brym, Ariella; Kurczek, Jake; Rosenbaum, R Shayna; Sheldon, Signy

2016-05-01

Constructing autobiographical events involves an initial phase of event selection, in which a memory or imagined future event is initially brought to mind, followed by a phase of elaboration, in which an individual accesses detailed knowledge specific to the event. While considerable research demonstrates the importance of the medial temporal lobes (MTL) in the later phase, its role in initial event selection is unknown. The present study is the first to investigate the role of the MTL in event selection by assessing whether individuals with MTL lesions select qualitatively different events for remembering and imagining than matched control participants. To do so, we created "event captions" that reflected the type of events selected for an autobiographical event narrative task by four individuals with MTL amnesia and control counterparts. Over 450 online raters assessed these event captions on qualitative dimensions known to vary with autobiographical recall (frequency, significance, emotionality, imageability, and uniqueness). Our critical finding was that individuals with MTL amnesia were more prone to select events that were rated as more frequently occurring than healthy control participants. We interpret this finding as evidence that people with impaired episodic memory from MTL damage compensate for their compromised ability to recall detailed information by relying more heavily on semantic memory processes to select generalized events. We discuss the implications for theoretical models of memory and methodological approaches to studying autobiographical memory. Copyright © 2016 Elsevier Ltd. All rights reserved.

Oscillatory patterns in temporal lobe reveal context reinstatement during memory search.

PubMed

Manning, Jeremy R; Polyn, Sean M; Baltuch, Gordon H; Litt, Brian; Kahana, Michael J

2011-08-02

Psychological theories of memory posit that when people recall a past event, they not only recover the features of the event itself, but also recover information associated with other events that occurred nearby in time. The events surrounding a target event, and the thoughts they evoke, may be considered to represent a context for the target event, helping to distinguish that event from similar events experienced at different times. The ability to reinstate this contextual information during memory search has been considered a hallmark of episodic, or event-based, memory. We sought to determine whether context reinstatement may be observed in electrical signals recorded from the human brain during episodic recall. Analyzing electrocorticographic recordings taken as 69 neurosurgical patients studied and recalled lists of words, we uncovered a neural signature of context reinstatement. Upon recalling a studied item, we found that the recorded patterns of brain activity were not only similar to the patterns observed when the item was studied, but were also similar to the patterns observed during study of neighboring list items, with similarity decreasing reliably with positional distance. The degree to which individual patients displayed this neural signature of context reinstatement was correlated with their tendency to recall neighboring list items successively. These effects were particularly strong in temporal lobe recordings. Our findings show that recalling a past event evokes a neural signature of the temporal context in which the event occurred, thus pointing to a neural basis for episodic memory.

Different effects of anterior temporal lobectomy and selective amygdalohippocampectomy on verbal memory performance of patients with epilepsy.

PubMed

Boucher, Olivier; Dagenais, Emmanuelle; Bouthillier, Alain; Nguyen, Dang Khoa; Rouleau, Isabelle

2015-11-01

The advantage of selective amygdalohippocampectomy (SAH) over anterior temporal lobectomy (ATL) for the treatment of temporal lobe epilepsy (TLE) remains controversial. Because ATL is more extensive and involves the lateral and medial parts of the temporal lobe, it may be predicted that its impact on memory is more important than SAH, which involves resection of medial temporal structures only. However, several studies do not support this assumption. Possible explanations include task-specific factors such as the extent of semantic and syntactic information to be memorized and failure to control for main confounders. We compared preoperative vs. postoperative memory performance in 13 patients with SAH with 26 patients who underwent ATL matched on side of surgery, IQ, age at seizure onset, and age at surgery. Memory function was assessed using the Logical Memory subtest from the Wechsler Memory Scales - 3rd edition (LM-WMS), the Rey Auditory Verbal Learning Test (RAVLT), the Digit Span subtest from the Wechsler Adult Intelligence Scale, and the Rey-Osterrieth Complex Figure Test. Repeated measures analyses of variance revealed opposite effects of SAH and ATL on the two verbal learning memory tests. On the immediate recall trial of the LM-WMS, performance deteriorated after ATL in comparison with that after SAH. By contrast, on the delayed recognition trial of the RAVLT, performance deteriorated after SAH compared with that after ATL. However, additional analyses revealed that the latter finding was only observed when surgery was conducted in the right hemisphere. No interaction effects were found on other memory outcomes. The results are congruent with the view that tasks involving rich semantic content and syntactical structure are more sensitive to the effects of lateral temporal cortex resection as compared with mesiotemporal resection. The findings highlight the importance of task selection in the assessment of memory in patients undergoing TLE surgery. Copyright © 2015 Elsevier Inc. All rights reserved.

The Influence of Frontal Lobe Tumors and Surgical Treatment on Advanced Cognitive Functions.

PubMed

Fang, Shengyu; Wang, Yinyan; Jiang, Tao

2016-07-01

Brain cognitive functions affect patient quality of life. The frontal lobe plays a crucial role in advanced cognitive functions, including executive function, meta-cognition, decision-making, memory, emotion, and language. Therefore, frontal tumors can lead to serious cognitive impairments. Currently, neurosurgical treatment is the primary method to treat brain tumors; however, the effects of the surgical treatments are difficult to predict or control. The treatment may both resolve the effects of the tumor to improve cognitive function or cause permanent disabilities resulting from damage to healthy functional brain tissue. Previous studies have focused on the influence of frontal lesions and surgical treatments on patient cognitive function. Here, we review cognitive impairment caused by frontal lobe brain tumors. Copyright © 2016 Elsevier Inc. All rights reserved.

Navigation-assisted trans-inferotemporal cortex selective amygdalohippocampectomy for mesial temporal lobe epilepsy; preserving the temporal stem.

PubMed

Kishima, Haruhiko; Kato, Amami; Oshino, Satoru; Tani, Naoki; Maruo, Tomoyuki; Khoo, Hui Ming; Yanagisawa, Takufumi; Edakawa, Kotaro; Kobayashi, Maki; Tanaka, Masataka; Hosomi, Koichi; Hirata, Masayuki; Yoshimine, Toshiki

2017-03-01

Selective amygdalohippocampectomy (SAH) can be used to obtain satisfactory seizure control in patients with mesial temporal lobe epilepsy (MTLE). Several SAH procedures have been reported to achieve satisfactory outcomes for seizure control, but none yield fully satisfactory outcomes for memory function. We hypothesized that preserving the temporal stem might play an important role. To preserve the temporal stem, we developed a minimally invasive surgical procedure, 'neuronavigation-assisted trans-inferotemporal cortex SAH' (TITC-SAH). TITC-SAH was performed in 23 patients with MTLE (MTLE on the language-non-dominant hemisphere, n = 11). The inferior horn of the lateral ventricle was approached via the inferior or middle temporal gyrus along the inferior temporal sulcus under neuronavigation guidance. The hippocampus was dissected in a subpial manner and resected en bloc together with the parahippocampal gyrus. Seizure control at one year and memory function at 6 months postoperatively were evaluated. One year after TITC-SAH, 20 of the 23 patients were seizure-free (ILAE class 1), 2 were class 2, and 1 was class 3. Verbal memory improved significantly in 13 patients with a diagnosis of hippocampal sclerosis, for whom WMS-R scores were available both pre- and post-operatively. Improvements were seen regardless of whether the SAH was on the language-dominant or non-dominant hemisphere. No major complication was observed. Navigation-assisted TITC-SAH performed for MTLE offers a simple, minimally invasive procedure that appears to yield excellent outcomes in terms of seizure control and preservation of memory function, because this procedure does not damage the temporal stem. TITC-SAH should be one of the feasible surgical procedures for MTLE. SAH: Amygdalohippocampectomy; MTLE: Mesial temporal lobe epilepsy (MTLE); TITC-SAH: Ttrans-inferotemporal cortex SAH; ILAE: International League Against Epilepsy (ILAE); MRI: Magnetic resonance imaging; EEG: Electroencephalography (EEG); FDG-PET: 8 F-fluorodeoxyglucose (FDG)-positron emission tomography; ECoG: Electrocorticography; MEG: Magnetoencephalography; IMZ-SPECT: N-isopropyl-p( 123 I)-iodoamphetamine single photon emission computed tomography; WMS-R: Wechsler Memory Scale-Revised.

True and false memories, parietal cortex, and confidence judgments

PubMed Central

Urgolites, Zhisen J.; Smith, Christine N.

2015-01-01

Recent studies have asked whether activity in the medial temporal lobe (MTL) and the neocortex can distinguish true memory from false memory. A frequent complication has been that the confidence associated with correct memory judgments (true memory) is typically higher than the confidence associated with incorrect memory judgments (false memory). Accordingly, it has often been difficult to know whether a finding is related to memory confidence or memory accuracy. In the current study, participants made recognition memory judgments with confidence ratings in response to previously studied scenes and novel scenes. The left hippocampus and 16 other brain regions distinguished true and false memories when confidence ratings were different for the two conditions. Only three regions (all in the parietal cortex) distinguished true and false memories when confidence ratings were equated. These findings illustrate the utility of taking confidence ratings into account when identifying brain regions associated with true and false memories. Neural correlates of true and false memories are most easily interpreted when confidence ratings are similar for the two kinds of memories. PMID:26472645

Rethinking cognition and behavior in the new classification for childhood epilepsy: Examples from frontal lobe and temporal lobe epilepsies.

PubMed

Smith, Mary Lou

2016-11-01

The new approach to classification of the epilepsies emphasizes the role of dysfunction in networks in defining types of epilepsies. This paper reviews the structural and neuropsychological deficits in two types of childhood epilepsy: frontal lobe and temporal lobe epilepsy. The evidence for and against a pattern of specificity of deficits in executive function and memory associated with these two types of epilepsies is presented. The evidence varies with the methodologies used in the studies, but direct comparison of the two types of epilepsies does not suggest a clear-cut mapping of function onto structure. These findings are discussed in light of the concept of network dysfunction. The evidence supports the conceptualization of epilepsy as a network disease. Implications for future work in the neuropsychology of pediatric epilepsy are suggested. This article is part of a Special Issue entitled "The new approach to classification: Rethinking cognition and behavior in epilepsy". Copyright © 2016 Elsevier Inc. All rights reserved.

Fornix and medial temporal lobe lesions lead to comparable deficits in complex visual perception.

PubMed

Lech, Robert K; Koch, Benno; Schwarz, Michael; Suchan, Boris

2016-05-04

Recent research dealing with the structures of the medial temporal lobe (MTL) has shifted away from exclusively investigating memory-related processes and has repeatedly incorporated the investigation of complex visual perception. Several studies have demonstrated that higher level visual tasks can recruit structures like the hippocampus and perirhinal cortex in order to successfully perform complex visual discriminations, leading to a perceptual-mnemonic or representational view of the medial temporal lobe. The current study employed a complex visual discrimination paradigm in two patients suffering from brain lesions with differing locations and origin. Both patients, one with extensive medial temporal lobe lesions (VG) and one with a small lesion of the anterior fornix (HJK), were impaired in complex discriminations while showing otherwise mostly intact cognitive functions. The current data confirmed previous results while also extending the perceptual-mnemonic theory of the MTL to the main output structure of the hippocampus, the fornix. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

'Tagging' along memories in aging: Synaptic tagging and capture mechanisms in the aged hippocampus.

PubMed

Shivarama Shetty, Mahesh; Sajikumar, Sreedharan

2017-05-01

Aging is accompanied by a general decline in the physiological functions of the body with the deteriorating organ systems. Brain is no exception to this and deficits in cognitive functions are quite common in advanced aging. Though a variety of age-related alterations are observed in the structure and function throughout the brain, certain regions show selective vulnerability. Medial temporal lobe, especially the hippocampus, is one such preferentially vulnerable region and is a crucial structure involved in the learning and long-term memory functions. Hippocampal synaptic plasticity, such as long-term potentiation (LTP) and depression (LTD), are candidate cellular correlates of learning and memory and alterations in these properties have been well documented in aging. A related phenomenon called synaptic tagging and capture (STC) has been proposed as a mechanism for cellular memory consolidation and to account for temporal association of memories. Mounting evidences from behavioral settings suggest that STC could be a physiological phenomenon. In this article, we review the recent data concerning STC and provide a framework for how alterations in STC-related mechanisms could contribute to the age-associated memory impairments. The enormity of impairment in learning and memory functions demands an understanding of age-associated memory deficits at the fundamental level given its impact in the everyday tasks, thereby in the quality of life. Such an understanding is also crucial for designing interventions and preventive measures for successful brain aging. Copyright © 2017 National University of Singapore. Published by Elsevier B.V. All rights reserved.

Episodic, but not semantic, autobiographical memory is reduced in amnestic mild cognitive impairment.

PubMed

Murphy, Kelly J; Troyer, Angela K; Levine, Brian; Moscovitch, Morris

2008-11-01

Amnestic mild cognitive impairment (aMCI) is characterized by decline in anterograde memory as measured by the ability to learn and remember new information. We investigated whether retrograde memory for autobiographical information was affected by aMCI. Eighteen control (age 66-84 years) and 17 aMCI (age 66-84 years) participants described a personal event from each of the five periods across the lifespan. These events were transcribed and scored according to procedures that separate episodic (specific happenings) from semantic (general knowledge) elements of autobiographical memory. Although both groups generated protocols of similar length, the composition of autobiographical recall differentiated the groups. The aMCI group protocols were characterized by reduced episodic and increased semantic information relative to the control group. Both groups showed a similar pattern of recall across time periods, with no evidence that the aMCI group had more difficulty recalling recent, rather than remote, life events. These results indicate that episodic and semantic autobiographical memories are differentially affected by the early brain changes associated with aMCI. Reduced autobiographical episodic memories in aMCI may be the result of medial temporal lobe dysfunction, consistent with multiple trace theory, or alternatively, could be related to dysfunction of a wider related network of neocortical structures. In contrast, the preservation of autobiographical semantic memories in aMCI suggests neural systems, such as lateral temporal cortex, that support these memories, may remain relatively intact.

Neuroanatomical Correlates of Theory of Mind Deficit in Parkinson’s Disease: A Multimodal Imaging Study

PubMed Central

Díez-Cirarda, María; Ojeda, Natalia; Peña, Javier; Cabrera-Zubizarreta, Alberto; Gómez-Beldarrain, María Ángeles; Gómez-Esteban, Juan Carlos; Ibarretxe-Bilbao, Naroa

2015-01-01

Background Parkinson’s disease (PD) patients show theory of mind (ToM) deficit since the early stages of the disease, and this deficit has been associated with working memory, executive functions and quality of life impairment. To date, neuroanatomical correlates of ToM have not been assessed with magnetic resonance imaging in PD. The main objective of this study was to assess cerebral correlates of ToM deficit in PD. The second objective was to explore the relationships between ToM, working memory and executive functions, and to analyse the neural correlates of ToM, controlling for both working memory and executive functions. Methods Thirty-seven PD patients (Hoehn and Yahr median = 2.0) and 15 healthy controls underwent a neuropsychological assessment and magnetic resonance images in a 3T-scanner were acquired. T1-weighted images were analysed with voxel-based morphometry, and white matter integrity and diffusivity measures were obtained from diffusion weighted images and analysed using tract-based spatial statistics. Results PD patients showed impairments in ToM, working memory and executive functions; grey matter loss and white matter reduction compared to healthy controls. Grey matter volume decrease in the precentral and postcentral gyrus, middle and inferior frontal gyrus correlated with ToM deficit in PD. White matter in the superior longitudinal fasciculus (adjacent to the parietal lobe) and white matter adjacent to the frontal lobe correlated with ToM impairment in PD. After controlling for executive functions, the relationship between ToM deficit and white matter remained significant for white matter areas adjacent to the precuneus and the parietal lobe. Conclusions Findings reinforce the existence of ToM impairment from the early Hoehn and Yahr stages in PD, and the findings suggest associations with white matter and grey matter volume decrease. This study contributes to better understand ToM deficit and its neural correlates in PD, which is a basic skill for development of healthy social relationships. PMID:26559669

Neuroanatomical Correlates of Theory of Mind Deficit in Parkinson's Disease: A Multimodal Imaging Study.

PubMed

Díez-Cirarda, María; Ojeda, Natalia; Peña, Javier; Cabrera-Zubizarreta, Alberto; Gómez-Beldarrain, María Ángeles; Gómez-Esteban, Juan Carlos; Ibarretxe-Bilbao, Naroa

2015-01-01

Parkinson's disease (PD) patients show theory of mind (ToM) deficit since the early stages of the disease, and this deficit has been associated with working memory, executive functions and quality of life impairment. To date, neuroanatomical correlates of ToM have not been assessed with magnetic resonance imaging in PD. The main objective of this study was to assess cerebral correlates of ToM deficit in PD. The second objective was to explore the relationships between ToM, working memory and executive functions, and to analyse the neural correlates of ToM, controlling for both working memory and executive functions. Thirty-seven PD patients (Hoehn and Yahr median = 2.0) and 15 healthy controls underwent a neuropsychological assessment and magnetic resonance images in a 3T-scanner were acquired. T1-weighted images were analysed with voxel-based morphometry, and white matter integrity and diffusivity measures were obtained from diffusion weighted images and analysed using tract-based spatial statistics. PD patients showed impairments in ToM, working memory and executive functions; grey matter loss and white matter reduction compared to healthy controls. Grey matter volume decrease in the precentral and postcentral gyrus, middle and inferior frontal gyrus correlated with ToM deficit in PD. White matter in the superior longitudinal fasciculus (adjacent to the parietal lobe) and white matter adjacent to the frontal lobe correlated with ToM impairment in PD. After controlling for executive functions, the relationship between ToM deficit and white matter remained significant for white matter areas adjacent to the precuneus and the parietal lobe. Findings reinforce the existence of ToM impairment from the early Hoehn and Yahr stages in PD, and the findings suggest associations with white matter and grey matter volume decrease. This study contributes to better understand ToM deficit and its neural correlates in PD, which is a basic skill for development of healthy social relationships.

 Cortical Atrophy is Associated with Accelerated Cognitive Decline in Mild Cognitive Impairment with Subsyndromal Depression.

PubMed

Gonzales, Mitzi M; Insel, Philip S; Nelson, Craig; Tosun, Duygu; Mattsson, Niklas; Mueller, Susanne G; Sacuiu, Simona; Bickford, David; Weiner, Michael W; Mackin, R Scott

2017-09-01

To investigate the association between cognitive decline and cortical atrophy in individuals with mild cognitive impairment (MCI) and chronic subsyndromal symptoms of depression (SSD) over a 4-year period. Prospective cohort study. Multicenter, clinic-based. Within the Alzheimer's Disease Neuroimaging Initiative repository, the Neuropsychiatric Inventory was used to identify individuals with MCI and stable endorsement (SSD group N = 32) or no endorsement (non-SSD group N = 69) of depressive symptoms across time points. Repeated measures of cognitive outcomes, cortical atrophy, and their associations were evaluated with mixed effects models adjusting for age, education, sex, and APOE genotype. The SSD group demonstrated accelerated decline on measures of global cognition (Alzheimer Disease Assessment Scale; df = 421, t = 2.242, p = 0.025), memory (Wechsler Memory Scale-Revised Logical Memory II; df = 244, t = -2.525, p = 0.011), information processing speed (Trail Making Test Parts A [df = 421, t = 2.376, p = 0.018] and B [df = 421, t = 2.533, p = 0.012]), and semantic fluency (Category Fluency; df = 424, t = -2.418, p = 0.016), as well as accelerated frontal lobe (df = 341, t = -2.648, p = 0.008) and anterior cingulate (df = 341, t = -3.786, p < 0.001) atrophy. No group differences were observed for rate of decline on measures of attention, learning, and confrontation naming or for rate of atrophy in any other regions. Accelerated frontal lobe and anterior cingulate atrophy was associated with cognitive decline on measures of global cognition, information processing speed, and semantic fluency (all p < 0.05), but not memory. Individuals with chronic SSD may represent an MCI subgroup that is highly vulnerable to accelerated cognitive decline, an effect that may be governed by frontal lobe and anterior cingulate atrophy. Published by Elsevier Inc.

Classic and recent advances in understanding amnesia.

PubMed

Allen, Richard J

2018-01-01

Neurological amnesia has been and remains the focus of intense study, motivated by the drive to understand typical and atypical memory function and the underlying brain basis that is involved. There is now a consensus that amnesia associated with hippocampal (and, in many cases, broader medial temporal lobe) damage results in deficits in episodic memory, delayed recall, and recollective experience. However, debate continues regarding the patterns of preservation and impairment across a range of abilities, including semantic memory and learning, delayed recognition, working memory, and imagination. This brief review highlights some of the influential and recent advances in these debates and what they may tell us about the amnesic condition and hippocampal function.

Losing sight of the future: Impaired semantic prospection following medial temporal lobe lesions

PubMed Central

Race, Elizabeth; Keane, Margaret M.; Verfaellie, Mieke

2012-01-01

The ability to imagine the future (prospection) relies on many of the same brain regions that support memory for the past. To date, scientific research has primarily focused on the neural substrates of episodic forms of prospection (mental simulation of spatiotemporally specific future events) whereas little is known about the neural substrates of semantic prospection (mental simulation of future nonpersonal facts). Of particular interest is the role of the medial temporal lobes, and specifically the hippocampus. While the hippocampus has been proposed to play a key role in episodic prospection, recent evidence suggests that it may not play a similar role in semantic prospection. To examine this possibility, amnesic patients with medial temporal lobe (MTL) lesions were asked to imagine future issues occurring in the public domain. The results showed that patients could list general semantic facts about the future, but when probed to elaborate, patients produced impoverished descriptions that lacked semantic detail. This impairment occurred despite intact performance on standard neuropsychological tests of semantic processing, and did not simply reflect deficits in narrative construction. The performance of a patient with damage limited to the hippocampus was similar to that of the remaining MTL patients and amnesic patients’ impaired elaboration of the semantic future correlated with their impaired elaboration of the semantic past. Together, these results provide novel evidence from MTL amnesia that memory and prospection are linked in the semantic domain and reveal that the medial temporal lobes play a critical role in the construction of detailed, multi-element semantic simulations. PMID:23197413

Brain volume change and cognitive trajectories in aging.

PubMed

Fletcher, Evan; Gavett, Brandon; Harvey, Danielle; Farias, Sarah Tomaszewski; Olichney, John; Beckett, Laurel; DeCarli, Charles; Mungas, Dan

2018-05-01

Examine how longitudinal cognitive trajectories relate to brain baseline measures and change in lobar volumes in a racially/ethnically and cognitively diverse sample of older adults. Participants were 460 older adults enrolled in a longitudinal aging study. Cognitive outcomes were measures of episodic memory, semantic memory, executive function, and spatial ability derived from the Spanish and English Neuropsychological Assessment Scales (SENAS). Latent variable multilevel modeling of the four cognitive outcomes as parallel longitudinal processes identified intercepts for each outcome and a second order global change factor explaining covariance among the highly correlated slopes. We examined how baseline brain volumes (lobar gray matter, hippocampus, and white matter hyperintensity) and change in brain volumes (lobar gray matter) were associated with cognitive intercepts and global cognitive change. Lobar volumes were dissociated into global and specific components using latent variable methods. Cognitive change was most strongly associated with brain gray matter volume change, with strong independent effects of global gray matter change and specific temporal lobe gray matter change. Baseline white matter hyperintensity and hippocampal volumes had significant incremental effects on cognitive decline beyond gray matter change. Baseline lobar gray matter was related to cognitive decline, but did not contribute beyond gray matter change. Cognitive decline was strongly influenced by gray matter volume change and, especially, temporal lobe change. The strong influence of temporal lobe gray matter change on cognitive decline may reflect involvement of temporal lobe structures that are critical for late life cognitive health but also are vulnerable to diseases of aging. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Neuropsychology Outcomes Following Trephine Epilepsy Surgery: The Inferior Temporal Gyrus Approach for Amygdalohippocampectomy in Medically Refractory Mesial Temporal Lobe Epilepsy.

PubMed

Schoenberg, Mike R; Clifton, William E; Sever, Ryan W; Vale, Fernando L

2018-06-01

Surgery is indicated in cases of mesial temporal lobe epilepsy(MTLE) that are refractory to medical management. The inferior temporal gyrus (ITG) approach provides access to the mesial temporal lobe (MTL) structures with minimal tissue disruption. Reported neuropsychology outcomes following this approach are limited. To report neuropsychological outcomes using an ITG approach to amygdalohippocampectomy (AH) in patients with medically refractory MTLE based on a prospective design. Fifty-four participants had Engel class I/II outcome following resection of MTL using the ITG approach. All participants had localization-related epilepsy confirmed by long-term surface video-electroencephalography and completed pre/postsurgical evaluations that included magnetic resonance imaging (MRI), Wada test or functional MRI, and neuropsychology assessment. Clinical semiology/video-electroencephalography indicated that of the 54 patients, 28 (52%) had left MTLE and 26 (48%) had right MTLE. Dominant hemisphere resections were performed on 23 patients (43%), nondominant on 31(57%). Twenty-nine (29) had pathology-confirmed mesial temporal sclerosis (MTS). Group level analyses found declines in verbal memory for patients with language-dominant resections (P < .05). No significant decline in neuropsychological measures occurred for patients with MTS. Participants without MTS who underwent a language-dominant lobe resection exhibited a significant decline in verbal and visual memory (P < .05). Nondominant resection participants did not exhibit significant change in neuropsychology scores (P > .05). Neuropsychology outcomes of an ITG approach for selective mesial temporal resection are comparable to other selective AH techniques showing minimal adverse cognitive effects. These data lend support to the ITG approach for selective AH as an option for MTLE.

Aberrant EEG functional connectivity and EEG power spectra in resting state post-traumatic stress disorder: a sLORETA study.

PubMed

Imperatori, Claudio; Farina, Benedetto; Quintiliani, Maria Isabella; Onofri, Antonio; Castelli Gattinara, Paola; Lepore, Marta; Gnoni, Valentina; Mazzucchi, Edoardo; Contardi, Anna; Della Marca, Giacomo

2014-10-01

The aim of the present study was to explore the modifications of EEG power spectra and EEG connectivity of resting state (RS) condition in patients with post-traumatic stress disorder (PTSD). Seventeen patients and seventeen healthy subjects matched for age and gender were enrolled. EEG was recorded during 5min of RS. EEG analysis was conducted by means of the standardized Low Resolution Electric Tomography software (sLORETA). In power spectra analysis PTSD patients showed a widespread increase of theta activity (4.5-7.5Hz) in parietal lobes (Brodmann Area, BA 7, 4, 5, 40) and in frontal lobes (BA 6). In the connectivity analysis PTSD patients also showed increase of alpha connectivity (8-12.5Hz) between the cortical areas explored by Pz-P4 electrode. Our results could reflect the alteration of memory systems and emotional processing consistently altered in PTSD patients. Copyright © 2014 Elsevier B.V. All rights reserved.

[Spatial Cognition and Episodic Memory Formation in the Limbic Cortex].

PubMed

Kobayashi, Yasushi

2017-04-01

The limbic lobe defined by Broca is a cortical region with highly diverse structure and functions, and comprises the paleo-, archi-, and neocortices as well as their transitional zones. In the limbic lobe, Brodmann designated areas 27, 28, 34, 35, and 36 adjacent to the hippocampus, and areas 23, 24, 25, 26, 29, 30, 31, 32, and 33 around the corpus callosum. In the current literature, areas 27 and 28 correspond to the presubiculum and entorhinal cortex, respectively. Area 34 represents the cortico-medial part of the amygdaloid complex. Areas 35 and 36 roughly cover the perirhinal and parahippocampal cortices. Areas 24, 25, 32, and 33 belong to the anterior cingulate gyrus, while areas 23, 26, 29, 30, and 31 to the posterior cingulate gyrus. Areas 25, 32, and the anteroinferior portion of area 24 are deeply involved in emotional responses, particularly in their autonomic functions, through reciprocal connections with the amygdaloid complex, anterior thalamus and projections to the brainstem and spinal visceral centers. Areas 29 and 30 have dense reciprocal connections with areas 23 and 31, the dorsolateral prefrontal areas, and the regions related to the hippocampus. They play pivotal roles in mediating spatial cognition, working memory processing, and episodic memory formation.

Retinal thinning is uniquely associated with medial temporal lobe atrophy in neurologically normal older adults

PubMed Central

Casaletto, Kaitlin B.; Ward, Michael E.; Baker, Nicholas S.; Bettcher, Brianne M.; Gelfand, Jeffrey M.; Li, Yaqiao; Chen, Robert; Dutt, Shubir; Miller, Bruce; Kramer, Joel H.; Green, Ari J.

2017-01-01

Given the converging pathologic and epidemiologic data indicating a relationship between retinal integrity and neurodegeneration, including Alzheimer’s disease (AD), we aimed to determine if retinal structure correlates with medial temporal lobe (MTL) structure and function in neurologically normal older adults. Spectral-domain optical coherence tomography, verbal and visual memory testing, and 3T-magnetic resonance imaging of the brain were performed in 79 neurologically normal adults enrolled in a healthy aging cohort study. Retinal nerve fiber thinning and reduced total macular and macular ganglion cell volumes were each associated with smaller MTL volumes (ps < 0.04). Notably, these markers of retinal structure were not associated with primary motor cortex or basal ganglia volumes (regions relatively unaffected in AD) (ps > 0.70), or frontal, precuneus, or temporoparietal volumes (regions affected in later AD Braak staging ps > 0.20). Retinal structure was not significantly associated with verbal or visual memory consolidation performances (ps > 0.14). Retinal structure was associated with MTL volumes, but not memory performances, in otherwise neurologically normal older adults. Given that MTL atrophy is a neuropathological hallmark of AD, retinal integrity may be an early marker of ongoing AD-related brain health. PMID:28068565

Dominance of objects over context in a mediotemporal lobe model of schizophrenia.

PubMed

Talamini, Lucia M; Meeter, Martijn

2009-08-04

A large body of evidence suggests impaired context processing in schizophrenia. Here we propose that this impairment arises from defective integration of mediotemporal 'what' and 'where' routes, carrying object and spatial information to the hippocampus. We have previously shown, in a mediotemporal lobe (MTL) model, that the abnormal connectivity between MTL regions observed in schizophrenia can explain the episodic memory deficits associated with the disorder. Here we show that the same neuropathology leads to several context processing deficits observed in patients with schizophrenia: 1) failure to choose subordinate stimuli over dominant ones when the former fit the context, 2) decreased contextual constraints in memory retrieval, as reflected in increased false alarm rates and 3) impaired retrieval of contextual information in source monitoring. Model analyses show that these deficits occur because the 'schizophrenic MTL' forms fragmented episodic representations, in which objects are overrepresented at the expense of spatial contextual information. These findings highlight the importance of MTL neuropathology in schizophrenia, demonstrating that it may underlie a broad spectrum of deficits, including context processing and memory impairments. It is argued that these processing deficits may contribute to central schizophrenia symptoms such as contextually inappropriate behavior, associative abnormalities, conversational drift, concreteness and delusions.

Direct Exploration of the Role of the Ventral Anterior Temporal Lobe in Semantic Memory: Cortical Stimulation and Local Field Potential Evidence From Subdural Grid Electrodes.

PubMed

Shimotake, Akihiro; Matsumoto, Riki; Ueno, Taiji; Kunieda, Takeharu; Saito, Satoru; Hoffman, Paul; Kikuchi, Takayuki; Fukuyama, Hidenao; Miyamoto, Susumu; Takahashi, Ryosuke; Ikeda, Akio; Lambon Ralph, Matthew A

2015-10-01

Semantic memory is a crucial higher cortical function that codes the meaning of objects and words, and when impaired after neurological damage, patients are left with significant disability. Investigations of semantic dementia have implicated the anterior temporal lobe (ATL) region, in general, as crucial for multimodal semantic memory. The potentially crucial role of the ventral ATL subregion has been emphasized by recent functional neuroimaging studies, but the necessity of this precise area has not been selectively tested. The implantation of subdural electrode grids over this subregion, for the presurgical assessment of patients with partial epilepsy or brain tumor, offers the dual yet rare opportunities to record cortical local field potentials while participants complete semantic tasks and to stimulate the functionally identified regions in the same participants to evaluate the necessity of these areas in semantic processing. Across 6 patients, and utilizing a variety of semantic assessments, we evaluated and confirmed that the anterior fusiform/inferior temporal gyrus is crucial in multimodal, receptive, and expressive, semantic processing. © The Author 2014. Published by Oxford University Press.

Age-related changes in parietal lobe activation during an episodic memory retrieval task.

PubMed

Oedekoven, Christiane S H; Jansen, Andreas; Kircher, Tilo T; Leube, Dirk T

2013-05-01

The crucial role of lateral parietal regions in episodic memory has been confirmed in previous studies. While aging has an influence on retrieval of episodic memory, it remains to be examined how the involvement of lateral parietal regions in episodic memory changes with age. We investigated episodic memory retrieval in two age groups, using faces as stimuli and retrieval success as a measure of episodic memory. Young and elderly participants showed activation within a similar network, including lateral and medial parietal as well as prefrontal regions, but elderly showed a higher level of brain activation regardless of condition. Furthermore, we examined functional connectivity in the two age groups and found a more extensive network in the young group, including correlations of parietal and prefrontal regions. In the elderly, the overall stronger activation related to memory performance may indicate a compensatory process for a less extensive functional network.

Out of place, out of mind: Schema-driven false memory effects for object-location bindings.

PubMed

Lew, Adina R; Howe, Mark L

2017-03-01

Events consist of diverse elements, each processed in specialized neocortical networks, with temporal lobe memory systems binding these elements to form coherent event memories. We provide a novel theoretical analysis of an unexplored consequence of the independence of memory systems for elements and their bindings, 1 that raises the paradoxical prediction that schema-driven false memories can act solely on the binding of event elements despite the superior retrieval of individual elements. This is because if 2, or more, schema-relevant elements are bound together in unexpected conjunctions, the unexpected conjunction will increase attention during encoding to both the elements and their bindings, but only the bindings will receive competition with evoked schema-expected bindings. We test our model by examining memory for object-location bindings in recognition (Study 1) and recall (Studies 2 and 3) tasks. After studying schema-relevant objects in unexpected locations (e.g., pan on a stool in a kitchen scene), participants who then viewed these objects in expected locations (e.g., pan on stove) at test were more likely to falsely remember this object-location pairing as correct, compared with participants that viewed a different unexpected object-location pairing (e.g., pan on floor). In recall, participants were more likely to correctly remember individual schema-relevant objects originally viewed in unexpected, as opposed to expected locations, but were then more likely to misplace these items in the original room scene to expected places, relative to control schema-irrelevant objects. Our theoretical analysis and novel paradigm provide a tool for investigating memory distortions acting on binding processes. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Neuropsychological outcomes after Gamma Knife radiosurgery for mesial temporal lobe epilepsy: a prospective multicenter study.

PubMed

Quigg, Mark; Broshek, Donna K; Barbaro, Nicholas M; Ward, Mariann M; Laxer, Kenneth D; Yan, Guofen; Lamborn, Kathleen

2011-05-01

To assess outcomes of language, verbal memory, cognitive efficiency and mental flexibility, mood, and quality of life (QOL) in a prospective, multicenter pilot study of Gamma Knife radiosurgery (RS) for mesial temporal lobe epilepsy (MTLE). RS, randomized to 20 Gy or 24 Gy comprising 5.5-7.5 ml at the 50% isodose volume, was performed on mesial temporal structures of patients with unilateral MTLE. Neuropsychological evaluations were performed at preoperative baseline, and mean change scores were described at 12 and 24 months postoperatively. QOL data were also available at 36 months. Thirty patients were treated and 26 were available for the final 24-month neuropsychological evaluation. Language (Boston Naming Test), verbal memory (California Verbal Learning Test and Logical Memory subtest of the Wechsler Memory Scale-Revised), cognitive efficiency and mental flexibility (Trail Making Test), and mood (Beck Depression Inventory) did not differ from baseline. QOL scores improved at 24 and 36 months, with those patients attaining seizure remission by month 24s accounting for the majority of the improvement. The serial changes in cognitive outcomes, mood, and QOL are unremarkable following RS for MTLE. RS may provide an alternative to open surgery, especially in those patients at risk of cognitive impairment or who desire a noninvasive alternative to open surgery. Wiley Periodicals, Inc. © 2011 International League Against Epilepsy.

Non-alcoholic Korsakoff syndrome in psychiatric patients with a history of undiagnosed Wernicke's encephalopathy.

PubMed

Nikolakaros, Georgios; Ilonen, Tuula; Kurki, Timo; Paju, Janina; Papageorgiou, Sokratis G; Vataja, Risto

2016-11-15

Wernicke's encephalopathy is often undiagnosed, particularly in non-alcoholics. There are very few reports of non-alcoholic patients diagnosed with Korsakoff syndrome in the absence of a prior diagnosis of Wernicke's encephalopathy and no studies of diffusion tensor imaging in non-alcoholic Korsakoff syndrome. We report on three non-alcoholic psychiatric patients (all women) with long-term non-progressive memory impairment that developed after malnutrition accompanied by at least one of the three Wernicke's encephalopathy manifestations: ocular abnormalities, ataxia or unsteadiness, and an altered mental state or mild memory impairment. In neuropsychological examination, all patients had memory impairment, including intrusions. One patient had mild cerebellar vermis atrophy in MRI taken after the second episode of Wernicke's encephalopathy. The same patient had mild hypometabolism in the lateral cortex of the temporal lobes. Another patient had mild symmetrical atrophy and hypometabolism of the superior frontal lobes. Two patients were examined with diffusion tensor imaging. Reduced fractional anisotropy values were found in the corona radiata in two patients, and the uncinate fasciculus and the inferior longitudinal fasciculus in one patient. Our results suggest that non-alcoholic Korsakoff syndrome is underdiagnosed. Psychiatric patients with long-term memory impairment may have Korsakoff syndrome and, therefore, they should be evaluated for a history of previously undiagnosed Wernicke's encephalopathy. Copyright © 2016 Elsevier B.V. All rights reserved.

Temporally graded semantic memory loss in amnesia and semantic dementia: Further evidence for opposite gradients.

PubMed

Estmacott, Robyn W; Moscovitch, Morris

2002-03-01

The consolidation theory of long-term memory (e.g., Squire, 1992) predicts that damage to the medial temporal lobes will result in temporally graded retrograde memory loss, with a disproportionate impairment of recent relative to remote knowledge; in contrast, severe atrophy of the temporal neocortex is predicted to result in the reverse temporally graded pattern, with a selective sparing of recent memory (K.S. Graham & Hodges, 1997). Previously, we reported evidence that autobiographical episodic memory does not follow this temporal pattern (Westmacott, Leach, Freedman, & Moscovitch, 2001). In the present study, we found evidence suggesting that semantic memory loss does follow the predicted temporal pattern. We used a set of tasks that tap implicit and explicit memory for famous names and English vocabulary terms from across the 20th century. KC, a person with medial temporal amnesia, consistently demonstrated across tasks a selective deficit for famous names and vocabulary terms from the 5-year period just prior to injury; this deficit was particularly profound for elaborated semantic knowledge (e.g., word definitions, occupation of famous person). However, when asked to guess on unfamiliar items, KC's performance for names and words from this 5-year time period increased substantially, suggesting that he retains some of this knowledge at an implicit or rudimentary level. Conversely, EL, a semantic dementia patient with temporal neocortical atrophy and relative sparing of the medial temporal lobe, demonstrated a selective sparing of names and words from the most recent time period. However, this selective sparing of recent semantic memory was demonstrated in the implicit tasks only; performance on explicit tasks suggested an equally severe impairment of semantics across all time periods. Unlike the data from our previous study of autobiographical episodic memory, these findings are consistent with the predictions both of consolidation theory (Hodges & Graham, 1998; Squire, 1992) and multiple trace theory (Nadel & Moscovitch, 1999) that the hippocampus plays a timelimited role in the acquisition and representation of long-term semantic memories. Moreover, our findings suggest that tasks requiring minimal verbal production and explicit recall may provide a more sensitive and comprehensive assessment of intact memory capacity in brain-damaged individuals.

Ventral Fronto-Temporal Pathway Supporting Cognitive Control of Episodic Memory Retrieval

PubMed Central

Barredo, Jennifer; Öztekin, Ilke; Badre, David

2015-01-01

Achieving our goals often requires guiding access to relevant information from memory. Such goal-directed retrieval requires interactions between systems supporting cognitive control, including ventrolateral prefrontal cortex (VLPFC), and those supporting declarative memory, such as the medial temporal lobes (MTL). However, the pathways by which VLPFC interacts with MTL during retrieval are underspecified. Prior neuroanatomical evidence suggests that a polysynaptic ventral fronto-temporal pathway may support VLPFC–MTL interactions. To test this hypothesis, human participants were scanned using fMRI during performance of a source-monitoring task. The strength of source information was varied via repetition during encoding. Single encoding events should produce a weaker memory trace, thus recovering source information about these items should demand greater cognitive control. Results demonstrated that cortical targets along the ventral path—anterior VLPFC, temporal pole, anterior parahippocampus, and hippocampus—exhibited increases in univariate BOLD response correlated with increases in controlled retrieval demand, independent of factors related to response selection. Further, a functional connectivity analysis indicated that these regions functionally couple and are distinguishable from a dorsal pathway related to response selection demands. These data support a ventral retrieval pathway linking PFC and MTL. PMID:24177990

Feature integration in visual working memory: parietal gamma activity is related to cognitive coordination

PubMed Central

Muthukumaraswamy, Suresh D.; Hibbs, Carina S.; Shapiro, Kimron L.; Bracewell, R. Martyn; Singh, Krish D.; Linden, David E. J.

2011-01-01

The mechanism by which distinct subprocesses in the brain are coordinated is a central conundrum of systems neuroscience. The parietal lobe is thought to play a key role in visual feature integration, and oscillatory activity in the gamma frequency range has been associated with perception of coherent objects and other tasks requiring neural coordination. Here, we examined the neural correlates of integrating mental representations in working memory and hypothesized that parietal gamma activity would be related to the success of cognitive coordination. Working memory is a classic example of a cognitive operation that requires the coordinated processing of different types of information and the contribution of multiple cognitive domains. Using magnetoencephalography (MEG), we report parietal activity in the high gamma (80–100 Hz) range during manipulation of visual and spatial information (colors and angles) in working memory. This parietal gamma activity was significantly higher during manipulation of visual-spatial conjunctions compared with single features. Furthermore, gamma activity correlated with successful performance during the conjunction task but not during the component tasks. Cortical gamma activity in parietal cortex may therefore play a role in cognitive coordination. PMID:21940605

Neuropsychological outcome after traumatic temporal lobe damage.

PubMed

Formisano, R; Schmidhuber-Eiler, B; Saltuari, L; Cigany, E; Birbamer, G; Gerstenbrand, F

1991-01-01

The most frequent sequelae after severe brain injury include changes in personality traits, disturbances of emotional behaviour and impairment of cognitive functions. In particular, emotional changes and/or verbal and non verbal dysfunctions were found in patients with bilateral or unilateral temporal lobe lesions. The aim of our study is to correlate the localization of the brain damage after severe brain injury, in particular of the temporal lobe, with the cognitive impairment and the emotional and behavioural changes resulting from these lesions. The patients with right temporal lobe lesions showed significantly better scores in verbal intelligence and verbal memory in comparison with patients with left temporal lobe lesions and those with other focal brain lesions or diffuse brain damage. In contradistinction, study of the personality and the emotional changes (MMPI and FAF) failed to demonstrate pathological scores in the 3 groups with different CT lesions, without any significant difference being found between the groups with temporal lesions and those with other focal brain lesions or diffuse brain damage. The severity of the brain injury and the prolongation of the disturbance of consciousness could, in our patients, account for prevalence of congnitive impairment on personality and emotional changes.

From amnesia to dementia: ERP studies of memory and language.

PubMed

Taylor, Jason R; Olichney, John M

2007-01-01

Cognitive event-related potential (ERP) studies of memory and language impairments in amnesia and Alzheimer's disease (AD) are reviewed. Well-circumscribed lesions of the medial temporal lobe (MTL) or diencephalon causing an amnestic syndrome, an inability to encode and retrieve episodic memories beyond the brief duration of working memory, appear to produce altered plasticity of the late positive P600 component, but usually spare P300 and N400 components. The neuropathology of AD affects MTL and extends to neocortical association areas, causing deficits of episodic and semantic memory. In AD dementia, the P300, N400, and P600 all commonly show abnormalities. ERP studies of individuals with mild cognitive impairment may reveal neurophysiological changes prior to the emergence of clinical deficits, which could advance the early detection and diagnosis of AD.

The relationship between neuropsychological tests of visuospatial function and lobar cortical thickness.

PubMed

Zink, Davor N; Miller, Justin B; Caldwell, Jessica Z K; Bird, Christopher; Banks, Sarah J

2018-06-01

Tests of visuospatial function are often administered in comprehensive neuropsychological evaluations. These tests are generally considered assays of parietal lobe function; however, the neural correlates of these tests, using modern imaging techniques, are not well understood. In the current study we investigated the relationship between three commonly used tests of visuospatial function and lobar cortical thickness in each hemisphere. Data from 374 patients who underwent a neuropsychological evaluation and MRI scans in an outpatient dementia clinic were included in the analysis. We examined the relationships between cortical thickness, as assessed with Freesurfer, and performance on three tests: Judgment of Line Orientation (JoLO), Block Design (BD) from the Fourth edition of the Wechsler Adult Intelligence Scale, and Brief Visuospatial Memory Test-Revised Copy Trial (BVMT-R-C) in patients who showed overall average performance on these tasks. Using a series of multiple regression models, we assessed which lobe's overall cortical thickness best predicted test performance. Among the individual lobes, JoLO performance was best predicted by cortical thickness in the right temporal lobe. BD performance was best predicted by cortical thickness in the right parietal lobe, and BVMT-R-C performance was best predicted by cortical thickness in the left parietal lobe. Performance on constructional tests of visuospatial function appears to correspond best with underlying cortical thickness of the parietal lobes, while performance on visuospatial judgment tests appears to correspond best to temporal lobe thickness. Future research using voxel-wise and connectivity techniques and including more diverse samples will help further understanding of the regions and networks involved in visuospatial tests.

Traumatic injury to the immature frontal lobe: a new murine model of long-term motor impairment in the absence of psychosocial or cognitive deficits.

PubMed

Chen, Chien-Yi; Noble-Haeusslein, Linda J; Ferriero, Donna; Semple, Bridgette D

2013-01-01

Traumatic brain injury in children commonly involves the frontal lobes and is associated with distinct structural and behavioral changes. Despite the clinical significance of injuries localized to this region during brain development, the mechanisms underlying secondary damage and long-term recovery are poorly understood. Here, we have characterized the first model of unilateral focal traumatic injury to the developing frontal lobe. Male C57Bl/6J mice at postnatal day (p)21, an age approximating a toddler-aged child, received a controlled cortical impact or sham surgery to the left frontal lobe and were euthanized 1 or 7 days later. A necrotic cavity and local inflammatory response were largely confined to the unilateral frontal lobe, dorsal corpus callosum and striatum anterior to the bregma. While cell death and accumulated β-amyloid precursor protein were characteristic features of the pericontusional motor cortex, corpus callosum, cingulum and dorsal striatum, underlying structures including the hippocampus showed no overt pathology. To determine the long-term functional consequences of injury at p21, two additional cohorts were subjected to a battery of behavioral tests in adolescence (p35-45) or adulthood (p70-80). In both cohorts, brain-injured mice showed normal levels of anxiety, sociability, spatial learning and memory. The signature phenotypic features were deficits in motor function and motor learning, coincident with a reduction in ipsilateral cortical brain volumes. Together, these findings demonstrate classic morphological features of a focal traumatic injury, including early cell death and axonal injury, and long-term volumetric loss of cortical volumes. The presence of deficits in sensorimotor function and coordination in the absence of abnormal findings related to anxiety, sociability and memory likely reflects several variables, including the unique location of the injury and the emergence of favorable compensatory mechanisms during subsequent brain development. © 2013 S. Karger AG, Basel.

Traumatic injury to the immature frontal lobe: A new murine model of long-term motor impairment in the absence of psychosocial or cognitive deficits

PubMed Central

Chen, Chien-Yi; Noble-Haeusslein, Linda J; Ferriero, Donna; Semple, Bridgette D

2014-01-01

Traumatic brain injury in children commonly involves the frontal lobes, and is associated with distinct structural and behavioral changes. Despite the clinical significance of injuries localized to this region during brain development, the mechanisms underlying secondary damage and long-term recovery are poorly understood. Here we have characterized the first model of unilateral focal traumatic injury to the developing frontal lobe. Male C57Bl/6J mice at postnatal day (p) 21, an age approximating a toddler-aged child, received a controlled cortical impact or sham surgery to the left frontal lobe and were euthanized 1 and 7 d later. A necrotic cavity and local inflammatory response were largely confined to the unilateral frontal lobe, dorsal corpus callosum and striatum anterior to Bregma. While cell death and accumulated beta-amyloid precursor protein were characteristic features of the peri-contusional motor cortex, corpus callosum, cingulum and dorsal striatum, underlying structures including the hippocampus showed no overt pathology. To determine the long-term functional consequences of injury at p21, two additional cohorts were subjected to a battery of behavioral tests in adolescence (p35-45) or adulthood (p70-80). In both cohorts, brain-injured mice showed normal levels of anxiety, sociability, spatial learning and memory. The signature phenotypic features were deficits in motor function and motor learning, coincident with a reduction in ipsilateral cortical brain volumes. Together, these findings demonstrate classic morphological features of a focal traumatic injury, including early cell death and axonal injury, and long-term volumetric loss of cortical volumes. The presence of deficits in sensorimotor function and coordination in the absence of abnormal findings related to anxiety, sociability and memory, likely reflect several variables including the unique location of the injury and the emergence of favorable compensatory mechanisms during subsequent brain development. PMID:24247103

CA1 neurons in the human hippocampus are critical for autobiographical memory, mental time travel, and autonoetic consciousness

PubMed Central

Bartsch, Thorsten; Döhring, Juliane; Rohr, Axel; Jansen, Olav; Deuschl, Günther

2011-01-01

Autobiographical memories in our lives are critically dependent on temporal lobe structures. However, the contribution of CA1 neurons in the human hippocampus to the retrieval of episodic autobiographical memory remains elusive. In patients with a rare acute transient global amnesia, highly focal lesions confined to the CA1 field of the hippocampus can be detected on MRI. We studied the effect of these lesions on autobiographical memory using a detailed autobiographical interview including the remember/know procedure. In 14 of 16 patients, focal lesions in the CA1 sector of the hippocampal cornu ammonis were detected. Autobiographical memory was significantly affected over all time periods, including memory for remote periods. Impairment of episodic memory and autonoetic consciousness exhibited a strong temporal gradient extending 30 to 40 y into the past. These results highlight the distinct and critical role of human hippocampal CA1 neurons in autobiographical memory retrieval and for re-experiencing detailed episodic memories. PMID:21987814

Inactivation of Primate Prefrontal Cortex Impairs Auditory and Audiovisual Working Memory.

PubMed

Plakke, Bethany; Hwang, Jaewon; Romanski, Lizabeth M

2015-07-01

The prefrontal cortex is associated with cognitive functions that include planning, reasoning, decision-making, working memory, and communication. Neurophysiology and neuropsychology studies have established that dorsolateral prefrontal cortex is essential in spatial working memory while the ventral frontal lobe processes language and communication signals. Single-unit recordings in nonhuman primates has shown that ventral prefrontal (VLPFC) neurons integrate face and vocal information and are active during audiovisual working memory. However, whether VLPFC is essential in remembering face and voice information is unknown. We therefore trained nonhuman primates in an audiovisual working memory paradigm using naturalistic face-vocalization movies as memoranda. We inactivated VLPFC, with reversible cortical cooling, and examined performance when faces, vocalizations or both faces and vocalization had to be remembered. We found that VLPFC inactivation impaired subjects' performance in audiovisual and auditory-alone versions of the task. In contrast, VLPFC inactivation did not disrupt visual working memory. Our studies demonstrate the importance of VLPFC in auditory and audiovisual working memory for social stimuli but suggest a different role for VLPFC in unimodal visual processing. The ventral frontal lobe, or inferior frontal gyrus, plays an important role in audiovisual communication in the human brain. Studies with nonhuman primates have found that neurons within ventral prefrontal cortex (VLPFC) encode both faces and vocalizations and that VLPFC is active when animals need to remember these social stimuli. In the present study, we temporarily inactivated VLPFC by cooling the cortex while nonhuman primates performed a working memory task. This impaired the ability of subjects to remember a face and vocalization pair or just the vocalization alone. Our work highlights the importance of the primate VLPFC in the processing of faces and vocalizations in a manner that is similar to the inferior frontal gyrus in the human brain. Copyright © 2015 the authors 0270-6474/15/359666-10$15.00/0.