Lavenex, Pamela Banta; Bostelmann, Mathilde; Brandner, Catherine; Costanzo, Floriana; Fragnière, Emilie; Klencklen, Giuliana; Lavenex, Pierre; Menghini, Deny; Vicari, Stefano
Studies have shown that persons with Down syndrome (DS) exhibit relatively poor language capacities, and impaired verbal and visuoperceptual memory, whereas their visuospatial memory capacities appear comparatively spared. Individuals with DS recall better where an object was previously seen than what object was previously seen. However, most of the evidence concerning preserved visuospatial memory comes from tabletop or computerized experiments which are biased toward testing egocentric (viewpoint-dependent) spatial representations. Accordingly, allocentric (viewpoint-independent) spatial learning and memory capacities may not be necessary to perform these tasks. Thus, in order to more fully characterize the spatial capacities of individuals with DS, allocentric processes underlying real-world navigation must also be investigated. We tested 20 participants with DS and 16 mental age-matched, typically developing (TD) children in a real-world, allocentric spatial (AS) memory task. During local cue (LC) trials, participants had to locate three rewards marked by local color cues, among 12 locations distributed in a 4 m × 4 m arena. During AS trials, participants had to locate the same three rewards, in absence of LCs, based on their relations to distal environmental cues. All TD participants chose rewarded locations in LC and AS trials at above chance level. In contrast, although all but one of the participants with DS exhibited a preference for the rewarded locations in LC trials, only 50% of participants with DS chose the rewarded locations at above chance level in AS trials. As a group, participants with DS performed worse than TD children on all measures of task performance. These findings demonstrate that individuals with DS are impaired at using an AS representation to learn and remember discrete locations in a controlled environment, suggesting persistent and pervasive deficits in hippocampus-dependent memory in DS. PMID:25762946
Lambert, Farfalla Ribordy; Lavenex, Pierre; Lavenex, Pamela Banta
Allocentric spatial memory, the memory for locations coded in relation to objects comprising our environment, is a fundamental component of episodic memory and is dependent on the integrity of the hippocampal formation in adulthood. Previous research from different laboratories reported that basic allocentric spatial memory abilities are reliably…
Parslow, David M; Morris, Robin G; Fleminger, Simon; Rahman, Qazi; Abrahams, Sharon; Recce, Michael
An immersive virtual reality (IVR) system was used to investigate allocentric spatial memory in a patient (PR) who had selective hippocampal damage, and also in patients who had undergone unilateral temporal lobectomies (17 right TL and 19 left TL), their performance compared against normal control groups. A human analogue of the Olton [Olton (1979). Hippocampus, space, and memory. Behavioural Brain Science, 2, 315] spatial maze was developed, consisting of a virtual room, a central virtual circular table and an array of radially arranged up-turned 'shells.' The participant had to search these shells in turn in order to find a blue 'cube' that would then 'move' to another location and so on, until all the shells had been target locations. Within-search errors could be made when the participants returned to a previously visited location during a search, and between-search errors when they revisited previously successful, but now incorrect locations. PR made significantly more between-search errors than his control group, but showed no increase in within-search errors. The right TL group showed a similar pattern of impairment, but the left TL group showed no impairment. This finding implicates the right hippocampal formation in spatial memory functioning in a scenario in which the visual environment was controlled so as to eliminate extraneous visual cues.
Ribordy, Farfalla; Jabes, Adeline; Lavenex, Pamela Banta; Lavenex, Pierre
Episodic memories for autobiographical events that happen in unique spatiotemporal contexts are central to defining who we are. Yet, before 2 years of age, children are unable to form or store episodic memories for recall later in life, a phenomenon known as infantile amnesia. Here, we studied the development of allocentric spatial memory, a…
Dzieciol, Anna M.; Gadian, David G.; Jentschke, Sebastian; Doeller, Christian F.; Burgess, Neil; Mishkin, Mortimer
The extent to which navigational spatial memory depends on hippocampal integrity in humans is not well documented. We investigated allocentric spatial recall using a virtual environment in a group of patients with severe hippocampal damage (SHD), a group of patients with “moderate” hippocampal damage (MHD), and a normal control group. Through four learning blocks with feedback, participants learned the target locations of four different objects in a circular arena. Distal cues were present throughout the experiment to provide orientation. A circular boundary as well as an intra-arena landmark provided spatial reference frames. During a subsequent test phase, recall of all four objects was tested with only the boundary or the landmark being present. Patients with SHD were impaired in both phases of this task. Across groups, performance on both types of spatial recall was highly correlated with memory quotient (MQ), but not with intelligence quotient (IQ), age, or sex. However, both measures of spatial recall separated experimental groups beyond what would be expected based on MQ, a widely used measure of general memory function. Boundary-based and landmark-based spatial recall were both strongly related to bilateral hippocampal volumes, but not to volumes of the thalamus, putamen, pallidum, nucleus accumbens, or caudate nucleus. The results show that boundary-based and landmark-based allocentric spatial recall are similarly impaired in patients with SHD, that both types of recall are impaired beyond that predicted by MQ, and that recall deficits are best explained by a reduction in bilateral hippocampal volumes. SIGNIFICANCE STATEMENT In humans, bilateral hippocampal atrophy can lead to profound impairments in episodic memory. Across species, perhaps the most well-established contribution of the hippocampus to memory is not to episodic memory generally but to allocentric spatial memory. However, the extent to which navigational spatial memory depends on
Parslow, David M; Rose, David; Brooks, Barbara; Fleminger, Simon; Gray, Jeffrey A; Giampietro, Vincent; Brammer, Michael J; Williams, Steven; Gasston, David; Andrew, Christopher; Vythelingum, Goparlen N; Loannou, Glafkos; Simmons, Andrew; Morris, Robin G
Hippocampal activation was investigated, comparing allocentric and egocentric spatial memory. Healthy participants were immersed in a virtual reality circular arena, with pattern-rendered walls. In a viewpoint-independent task, they moved toward a pole, which was then removed. They were relocated to another position and had to move to the prior location of the pole. For viewpoint-dependent memory, the participants were not moved to a new starting point, but the patterns were rotated to prevent them from indicating the final position. Hippocampal and parahippocampal activation were found in the viewpoint-independent memory encoding phase. Viewpoint-dependent memory did not result in such activation. These results suggest differential activation of the hippocampal formation during allocentric encoding, in partial support of the spatial mapping hypothesis as applied to humans.
Ribordy Lambert, Farfalla; Lavenex, Pierre; Banta Lavenex, Pamela
Allocentric spatial memory, "where" with respect to the surrounding environment, is one of the three fundamental components of episodic memory: what, where, when. Whereas basic allocentric spatial memory abilities are reliably observed in children after 2 years of age, coinciding with the offset of infantile amnesia, the resolution of allocentric spatial memory acquired over repeated trials improves from 2 to 4 years of age. Here, we first show that single-trial allocentric spatial memory performance improves in children from 3.5 to 7 years of age, during the typical period of childhood amnesia. Second, we show that large individual variation exists in children's performance at this age. Third, and most importantly, we show that improvements in single-trial allocentric spatial memory performance are due to an increasing ability to spatially and temporally separate locations and events. Such improvements in spatial and temporal processing abilities may contribute to the gradual offset of childhood amnesia.
Banta Lavenex, Pamela; Lecci, Sandro; Prêtre, Vincent; Brandner, Catherine; Mazza, Christian; Pasquier, Jérôme; Lavenex, Pierre
We aimed to determine whether human subjects' reliance on different sources of spatial information encoded in different frames of reference (i.e., egocentric versus allocentric) affects their performance, decision time and memory capacity in a short-term spatial memory task performed in the real world. Subjects were asked to play the Memory game (a.k.a. the Concentration game) without an opponent, in four different conditions that controlled for the subjects' reliance on egocentric and/or allocentric frames of reference for the elaboration of a spatial representation of the image locations enabling maximal efficiency. We report experimental data from young adult men and women, and describe a mathematical model to estimate human short-term spatial memory capacity. We found that short-term spatial memory capacity was greatest when an egocentric spatial frame of reference enabled subjects to encode and remember the image locations. However, when egocentric information was not reliable, short-term spatial memory capacity was greater and decision time shorter when an allocentric representation of the image locations with respect to distant objects in the surrounding environment was available, as compared to when only a spatial representation encoding the relationships between the individual images, independent of the surrounding environment, was available. Our findings thus further demonstrate that changes in viewpoint produced by the movement of images placed in front of a stationary subject is not equivalent to the movement of the subject around stationary images. We discuss possible limitations of classical neuropsychological and virtual reality experiments of spatial memory, which typically restrict the sensory information normally available to human subjects in the real world.
Ribordy, Farfalla; Jabès, Adeline; Banta Lavenex, Pamela; Lavenex, Pierre
Episodic memories for autobiographical events that happen in unique spatiotemporal contexts are central to defining who we are. Yet, before 2 years of age, children are unable to form or store episodic memories for recall later in life, a phenomenon known as infantile amnesia. Here, we studied the development of allocentric spatial memory, a fundamental component of episodic memory, in two versions of a real-world memory task requiring 18 month- to 5-year-old children to search for rewards hidden beneath cups distributed in an open-field arena. Whereas children 25-42-months-old were not capable of discriminating three reward locations among 18 possible locations in absence of local cues marking these locations, children older than 43 months found the reward locations reliably. These results support previous findings suggesting that allocentric spatial memory, if present, is only rudimentary in children under 3.5 years of age. However, when tested with only one reward location among four possible locations, children 25-39-months-old found the reward reliably in absence of local cues, whereas 18-23-month-olds did not. Our findings thus show that the ability to form a basic allocentric representation of the environment is present by 2 years of age, and its emergence coincides temporally with the offset of infantile amnesia. However, the ability of children to distinguish and remember closely related spatial locations improves from 2 to 3.5 years of age, a developmental period marked by persistent deficits in long-term episodic memory known as childhood amnesia. These findings support the hypothesis that the differential maturation of distinct hippocampal circuits contributes to the emergence of specific memory processes during early childhood.
Sarkisyan, Gor; Hedlund, Peter B
The hippocampus has been implicated in aspects of spatial memory. Its ability to generate new neurons has been suggested to play a role in memory formation. Hippocampal serotonin (5-HT) neurotransmission has also been proposed as a contributor to memory processing. Studies have shown that the 5-HT(7) receptor is present in the hippocampus in relatively high abundance. Thus the aim of the present study was to investigate the possible role of the 5-HT(7) receptor in spatial memory using 5-HT(7) receptor-deficient mice (5-HT(7)(-/-)). A hippocampus-associated spatial memory deficit in 5-HT(7)(-/-) mice was demonstrated using a novel location/novel object test. A similar reduction in novel location exploration was observed in C57BL/6J mice treated with the selective 5-HT(7) receptor antagonist SB-269970. These findings prompted an extended analysis using the Barnes maze demonstrating that 5-HT(7)(-/-) mice were less efficient in accommodating to changes in spatial arrangement than 5-HT(7)(+/+) mice. 5-HT(7)(-/-) mice had specific impairments in memory compilation required for resolving spatial tasks, which resulted in impaired allocentric spatial memory whereas egocentric spatial memory remained intact after the mice were forced to switch back from striatum-dependent egocentric to hippocampus-dependent allocentric memory. To further investigate the physiological bases underlining these behaviors we compared hippocampal neurogenesis in 5-HT(7)(+/+) and 5-HT(7)(-/-) mice employing BrdU immunohistochemistry. The rate of cell proliferation in the dentate gyrus was identical in the two genotypes. From the current data we conclude that the 5-HT(7)(-/-) mice performed by remembering a simple sequence of actions that resulted in successfully locating a hidden target in a static environment.
Soblosky, J S; Tabor, S L; Matthews, M A; Davidson, J F; Chorney, D A; Carey, M E
Traumatic brain injury (TBI) produces learning and memory impairments in humans. This study investigated the effects of TBI on memory and spatial localization strategies in rats. Prior to TBI, separate groups of rats were trained in an 8-arm radial maze with either all 8 arms baited (Expt. 1) or only 4 of the 8 arms baited (Expt. 2). TBI was produced by a controlled pneumatic impactor striking the entire right sensorimotor cortex of the anesthetized rat. Rats used in Expt. 1 were selected because they did not use a stereotypic response strategy (going to adjacent arms) in performing the maze before injury. After TBI the rats were not different from control rats in the number of working memory (WM) errors made. They did, however, display a distinct propensity to go to adjacent arms, i.e., exhibit stereotypic behavior, with a right-handed (ipsiversive) bias (P < 0.005). After TBI, rats which were trained with only 4 of 8 arms baited committed more reference memory (RM) errors than control rats (P < 0.05). They did not differ from controls on WM errors. Injured rats took longer to re-attain criteria than controls (P < 0.0001). Injured rats also initially displayed a propensity to enter the adjacent arm sequentially before re-attaining criteria. Further analysis indicated that injured rats re-learned the maze with a right-hand bias (P < 0.0001). The results of both experiments suggest that after TBI, rats shifted from an allocentric to an egocentric strategy to re-learn the maze. It was suggested that damage to the parietal cortex may have been responsible for both RM errors and the shift away from an allocentric strategy to an egocentric strategy. Possibly, the ipsiversive (right-hand) bias may be the result of a behaviorally or injury-induced neurochemical asymmetry within the motor system.
Rogers, Jake; Churilov, Leonid; Hannan, Anthony J; Renoir, Thibault
Using a Matlab classification algorithm, we demonstrate that a highly salient distal cue array is required for significantly increased likelihoods of spatial search strategy selection during Morris water maze spatial learning. We hypothesized that increased spatial search strategy selection during spatial learning would be the key measure demonstrating the formation of an allocentric map to the escape location. Spatial memory, as indicated by quadrant preference for the area of the pool formally containing the hidden platform, was assessed as the main measure that this allocentric map had formed during spatial learning. Our C57BL/6J wild-type (WT) mice exhibit quadrant preference in the highly salient cue paradigm but not the low, corresponding with a 120% increase in the odds of a spatial search strategy selection during learning. In contrast, quadrant preference remains absent in serotonin 1A receptor (5-HT1AR) knockout (KO) mice, who exhibit impaired search strategy selection during spatial learning. Additionally, we also aimed to assess the impact of the quality of the distal cue array on the spatial learning curves of both latency to platform and path length using mixed-effect regression models and found no significant associations or interactions. In contrast, we demonstrated that the spatial learning curve for search strategy selection was absent during training in the low saliency paradigm. Therefore, we propose that allocentric search strategy selection during spatial learning is the learning parameter in mice that robustly indicates the formation of a cognitive map for the escape goal location. These results also suggest that both latency to platform and path length spatial learning curves do not discriminate between allocentric and egocentric spatial learning and do not reliably predict spatial memory formation. We also show that spatial memory, as indicated by the absolute time in the quadrant formerly containing the hidden platform alone (without
Wood, Ruth A.; Moodley, Kuven K.; Lever, Colin; Minati, Ludovico; Chan, Dennis
The hippocampus is one of the first regions to exhibit neurodegeneration in Alzheimer’s disease (AD), and knowledge of its role in allocentric spatial memory may therefore aid early diagnosis of AD. The 4 Mountains Test (4MT) is a short and easily administered test of spatial memory based on the cognitive map theory of hippocampal function as derived from rodent single cell and behavioral studies. The 4MT has been shown in previous cross-sectional studies to be sensitive and specific for mild cognitive impairment (MCI) due to AD. This report describes the initial results of a longitudinal study testing the hypothesis that allocentric spatial memory is predictive of conversion from MCI to dementia. Fifteen patients with MCI underwent baseline testing on the 4MT in addition to CSF amyloid/tau biomarker studies, volumetric MRI and neuropsychological assessment including the Rey Auditory Verbal Learning Test (RAVLT) and Trail Making Test “B” (TMT-B). At 24 months, 9/15 patients had converted to AD dementia. The 4MT predicted conversion to AD with 93% accuracy (Cohen’s d = 2.52). The predictive accuracies of the comparator measures were as follows: CSF tau/β-amyloid1–42 ratio 92% (d = 1.81), RAVLT 64% (d = 0.41), TMT-B 78% (d = 1.56), and hippocampal volume 77% (d = 0.65). CSF tau levels were strongly negatively correlated with 4MT scores (r = −0.71). This proof-of-concept study provides initial support for the hypothesis that allocentric spatial memory testing is a predictive cognitive marker of hippocampal neurodegeneration in pre-dementia AD. The 4MT is a brief, non-invasive, straightforward spatial memory test and is therefore ideally suited for use in routine clinical diagnostic practice. This is of particular importance given the current unmet need for simple accurate diagnostic tests for early AD and the ongoing development of potential disease-modifying therapeutic agents, which may be more efficacious when given earlier in
Antonova, Elena; Parslow, David; Brammer, Michael; Simmons, Andrew; Williams, Steven; Dawson, Gerard R; Morris, Robin
The role of the septohippocampal cholinergic system in memory disorders is well established. The effects of cholinergic challenge in animals have been extensively studied using the Morris Water Maze (MWM) which engages allocentric spatial memory. The present study investigated the effect of the centrally active muscarinic antagonist scopolamine on allocentric spatial memory in humans using a virtual reality analogue of the MWM task, the Arena task. Twenty right-handed healthy male adults with a mean age of 28 years (range 23-35 years) were studied using functional MRI in a randomized double-blind cross-over design with scopolamine bromide (0.4 mg i.m.) or placebo (saline) administered 70-90 min before the beginning of the functional scan. Scopolamine induced a significant reduction in the activation of the hippocampus/parahippocampal gyrus compared with placebo. Furthermore, there was dissociation between hippocampus-based and striatal-based memory systems, which were significantly more activated in the placebo and scopolamine conditions, respectively. The activation of the striatal system under scopolamine challenge was accompanied by the activation of the amygdala. In conclusion, the study extends the well-documented finding in animals of the attenuating effect of scopolamine on hippocampal activity during allocentric spatial memory to humans. Furthermore, the results call for further investigation of the dissociation between the hippocampal and neostriatal memory systems during allocentric spatial processing under cholinergic blockade in humans.
Ramos, Juan M J
Rats with hippocampal, perirhinal cortex and postrhinal cortex lesions were trained in a reference spatial memory task to determine whether these structures contribute differentially to the acquisition and retention of spatial information. The results of Experiment 1 indicated that hippocampal lesions profoundly impaired the acquisition of the task. However, postrhinal lesions produced only a mild deficit and perirhinal lesions produced no deficit whatsoever in the learning of the task. During acquisition, hippocampus-damaged rats committed more perseverative errors than postrhinal rats, suggesting that the nature of the operations performed by each of these structures is different. The results of Experiment 2 showed a profound deficit in retention in hippocampal and postrhinal-lesioned animals tested 24 days after training. Perirhinal-lesioned animals, however, executed the task just as well as the control subjects did. These functional data, in consonance with existing connectivity data, suggest that each of these medial temporal lobe regions makes a different contribution to allocentric spatial learning and memory.
Ekstrom, Arne D.; Arnold, Aiden E. G. F.; Iaria, Giuseppe
While the widely studied allocentric spatial representation holds a special status in neuroscience research, its exact nature and neural underpinnings continue to be the topic of debate, particularly in humans. Here, based on a review of human behavioral research, we argue that allocentric representations do not provide the kind of map-like, metric representation one might expect based on past theoretical work. Instead, we suggest that almost all tasks used in past studies involve a combination of egocentric and allocentric representation, complicating both the investigation of the cognitive basis of an allocentric representation and the task of identifying a brain region specifically dedicated to it. Indeed, as we discuss in detail, past studies suggest numerous brain regions important to allocentric spatial memory in addition to the hippocampus, including parahippocampal, retrosplenial, and prefrontal cortices. We thus argue that although allocentric computations will often require the hippocampus, particularly those involving extracting details across temporally specific routes, the hippocampus is not necessary for all allocentric computations. We instead suggest that a non-aggregate network process involving multiple interacting brain areas, including hippocampus and extra-hippocampal areas such as parahippocampal, retrosplenial, prefrontal, and parietal cortices, better characterizes the neural basis of spatial representation during navigation. According to this model, an allocentric representation does not emerge from the computations of a single brain region (i.e., hippocampus) nor is it readily decomposable into additive computations performed by separate brain regions. Instead, an allocentric representation emerges from computations partially shared across numerous interacting brain regions. We discuss our non-aggregate network model in light of existing data and provide several key predictions for future experiments. PMID:25346679
Ramos, Juan M J
Several studies have shown that slight modifications in the standard reference spatial memory procedure normally used for allocentric learning in the Morris water maze and the radial maze, can overcome the classic deficit in allocentric navigation typically observed in rats with hippocampal damage. In these special paradigms, however, there is only intramaze manipulation of a salient stimulus. The present study was designed to investigate whether extramaze manipulations produce a similar outcome. With this aim a four-arm plus-shaped maze and a reference spatial memory paradigm were used, in which the goal arm was marked in two ways: by a prominent extramaze cue (intermittent light), which maintained a constant relation with the goal, and by the extramaze constellation of stimuli around the maze. Experiment 1 showed that, unlike the standard version of the task, using this special training procedure hippocampally-damaged rats could learn a place response as quickly as control animals; importantly, one day after reaching criterion, lesioned and control subjects performed the task perfectly during a transfer test in which the salient extramaze stimulus used during the acquisition was removed. However, although acquisition deficit was overcomed in these lesioned animals, a profound deficit in retention was detected 15 days later. Experiment 2 suggests that although under our special paradigm hippocampal rats can learn a place response, spatial memory only can be expressed when the requisites of behavioral flexibility are minimal. These findings suggest that, under certain circumstances, extrahippocampal structures are sufficient for building a coherent allocentric representation of space; however, flexible memory expression is dependent, fundamentally, on hippocampal functioning.
Ruggiero, Gennaro; D'Errico, Ortensia; Iachini, Tina
Spatial reference frames are fundamental to represent the position of objects or places. Although research has reported changes in spatial memory abilities during childhood and elderly age, no study has assessed reference frames processing during the entire lifespan using the same task. Here, we aimed at providing some preliminary data on the capacity to process reference frames in 283 healthy participants from 6 to 89 years of age. A spatial memory task requiring egocentric/allocentric verbal judgments about objects in peri-/extrapersonal space was used. The main goals were: (1) tracing a baseline of the normal process of development of these spatial components; (2) clarifying if reference frames are differently vulnerable to age-related effects. Results showed a symmetry between children of 6-7 years and older people of 80-89 years who were slower and less accurate than all other age groups. As regards processing time, age had a strong effect on the allocentric component, especially in extrapersonal space, with a longer time in 6- to 7-year-old children and 80- to 89-year-old adults. The egocentric component looked less affected by aging. Regarding the level of spatial ability (accuracy), the allocentric ability appeared less sensitive to age-related variations, whereas the egocentric ability progressively improved from 8 years and declined from 60 years. The symmetry in processing time and level of spatial ability is discussed in relation to the development of executive functions and to the structural and functional changes due to incomplete maturation (in youngest children) and deterioration (in oldest adults) of underlying cerebral areas.
van Gerven, Dustin J H; Ferguson, Thomas; Skelton, Ronald W
Stress and stress hormones are known to influence the function of the hippocampus, a brain structure critical for cognitive-map-based, allocentric spatial navigation. The caudate nucleus, a brain structure critical for stimulus-response-based, egocentric navigation, is not as sensitive to stress. Evidence for this comes from rodent studies, which show that acute stress or stress hormones impair allocentric, but not egocentric navigation. However, there have been few studies investigating the effect of acute stress on human spatial navigation, and the results of these have been equivocal. To date, no study has investigated whether acute stress can shift human navigational strategy selection between allocentric and egocentric navigation. The present study investigated this question by exposing participants to an acute psychological stressor (the Paced Auditory Serial Addition Task, PASAT), before testing navigational strategy selection in the Dual-Strategy Maze, a modified virtual Morris water maze. In the Dual-Strategy maze, participants can chose to navigate using a constellation of extra-maze cues (allocentrically) or using a single cue proximal to the goal platform (egocentrically). Surprisingly, PASAT stress biased participants to solve the maze allocentrically significantly more, rather than less, often. These findings have implications for understanding the effects of acute stress on cognitive function in general, and the function of the hippocampus in particular.
Iachini, Tina; Ruggiero, Gennaro; Conson, Massimiliano; Trojano, Luigi
The purpose of this paper was to verify whether left and right parietal brain lesions may selectively impair egocentric and allocentric processing of spatial information in near/far spaces. Two Right-Brain-Damaged (RBD), 2 Left-Brain-Damaged (LBD) patients (not affected by neglect or language disturbances) and eight normal controls were submitted…
Gomez, Alice; Cerles, Mélanie; Rousset, Stéphane; Rémy, Chantal; Baciu, Monica
The way new spatial information is encoded seems to be crucial in disentangling the role of decisive regions within the spatial memory network (i.e., hippocampus, parahippocampal, parietal, retrosplenial,…). Several data sources converge to suggest that the hippocampus is not always involved or indeed necessary for allocentric processing. Hippocampal involvement in spatial coding could reflect the integration of new information generated by "online" self-related changes. In this fMRI study, the participants started by encoding several object locations in a virtual reality environment and then performed a pointing task. Allocentric encoding was maximized by using a survey perspective and an object-to-object pointing task. Two egocentric encoding conditions were used, involving self-related changes processed under a first-person perspective and implicating a self-to-object pointing task. The Egocentric-updating condition involved navigation whereas the Egocentric with rotation only condition involved orientation changes only. Conjunction analysis of spatial encoding conditions revealed a wide activation of the occipito-parieto-frontal network and several medio-temporal structures. Interestingly, only the cuneal areas were significantly more recruited by the allocentric encoding in comparison to other spatial conditions. Moreover, the enhancement of hippocampal activation was found during Egocentric-updating encoding whereas the retrosplenial activation was observed during the Egocentric with rotation only condition. Hence, in some circumstances, hippocampal and retrosplenial structures-known for being involved in allocentric environmental coding-demonstrate preferential involvement in the egocentric coding of space. These results indicate that the raw differentiation between allocentric versus egocentric representation seems to no longer be sufficient in understanding the complexity of the mechanisms involved during spatial encoding.
Rubio, S; Begega, A; Méndez, M; Méndez-López, M; Arias, J L
The involvement of different brain regions in place- and response-learning was examined using a water cross-maze. Rats were trained to find the goal from the initial arm by turning left at the choice point (egocentric strategy) or by using environmental cues (allocentric strategy). Although different strategies were required, the same maze and learning conditions were used. Using cytochrome oxidase histochemistry as a marker of cellular activity, the function of the 13 diverse cortical and subcortical regions was assessed in rats performing these two tasks. Our results show that allocentric learning depends on the recruitment of a large functional network, which includes the hippocampal CA3, dentate gyrus, medial mammillary nucleus and supramammillary nucleus. Along with the striatum, these last three structures are also related to egocentric spatial learning. The present study provides evidence for the contribution of these regions to spatial navigation and supports a possible functional interaction between the two memory systems, as their structural convergence may facilitate functional cooperation in the behaviours guided by more than one strategy. In summary, it can be argued that spatial learning is based on dynamic functional systems in which the interaction of brain regions is modulated by task requirements.
Dijkerman, H C; Milner, A D; Carey, D P
The cortical visual mechanisms involved in processing spatial relationships remain subject to debate. According to one current view, the "dorsal stream" of visual areas, emanating from primary visual cortex and culminating in the posterior parietal cortex, mediates this aspect of visual processing. More recently, others have argued that while the dorsal stream provides egocentric coding of visual location for motor control, the separate "ventral" stream is needed for allocentric spatial coding. We have assessed the visual form agnosic patient DF, whose lesion mainly affects the ventral stream, on a prehension task requiring allocentric spatial coding. She was presented with transparent circular disks. Each disk had circular holes cut in it. DF was asked to reach out and grasp the disk by placing her fingers through the holes. The disks either had three holes (for forefinger, middle finger, and thumb) or two holes (for forefinger and thumb). The distance between the forefinger and thumb holes, and the orientation of the line formed by them, were independently varied. DF was quite unable to adjust her grip aperture or her hand orientation in the three-hole task. Although she was able to orient her hand appropriately for the two-hole disks, she still remained unable to adjust her grip aperture to the distance between the holes. These findings are consistent with the idea that allocentric processing of spatial information requires a functioning ventral stream, even when the information is being used to guide a motor response.
Vorhees, Charles V.; Williams, Michael T.
Maneuvering safely through the environment is central to survival of almost all species. The ability to do this depends on learning and remembering locations. This capacity is encoded in the brain by two systems: one using cues outside the organism (distal cues), allocentric navigation, and one using self-movement, internal cues and nearby proximal cues, egocentric navigation. Allocentric navigation involves the hippocampus, entorhinal cortex, and surrounding structures; in humans this system encodes allocentric, semantic, and episodic memory. This form of memory is assessed in laboratory animals in many ways, but the dominant form of assessment is the Morris water maze (MWM). Egocentric navigation involves the dorsal striatum and connected structures; in humans this system encodes routes and integrated paths and, when overlearned, becomes procedural memory. In this article, several allocentric assessment methods for rodents are reviewed and compared with the MWM. MWM advantages (little training required, no food deprivation, ease of testing, rapid and reliable learning, insensitivity to differences in body weight and appetite, absence of nonperformers, control methods for proximal cue learning, and performance effects) and disadvantages (concern about stress, perhaps not as sensitive for working memory) are discussed. Evidence-based design improvements and testing methods are reviewed for both rats and mice. Experimental factors that apply generally to spatial navigation and to MWM specifically are considered. It is concluded that, on balance, the MWM has more advantages than disadvantages and compares favorably with other allocentric navigation tasks. PMID:25225309
Negen, James; Heywood-Everett, Edward; Roome, Hannah E; Nardini, Marko
Using landmarks and other scene features to recall locations from new viewpoints is a critical skill in spatial cognition. In an immersive virtual reality task, we asked children 3.5-4.5 years old to remember the location of a target using various cues. On some trials they could use information from their own self-motion. On some trials they could use a view match. In the very hardest kind of trial, they were 'teleported' to a new viewpoint and could only use an allocentric spatial representation. This approach provides a strict test for allocentric coding (without either a matching viewpoint or self-motion information) while avoiding additional task demands in previous studies (it does not require them to deal with a small table-top environment or to manage stronger cue conflicts). Both the younger and older groups were able to point back at the target location better than chance when they could use view matching and/or self-motion, but allocentric recall was only seen in the older group (4.0-4.5). In addition, we only obtained evidence for a specific kind of allocentric recall in the older group: they tracked one major axis of the space significantly above chance, r(158) = .28, but not the other, r(158) = -.01. We conclude that there is a major qualitative change in coding for spatial recall around the fourth birthday, potentially followed by further development towards fully flexible recall from new viewpoints.
The use and neural representation of egocentric spatial reference frames is well-documented. In contrast, whether the brain represents spatial relationships between objects in allocentric, object-centered, or world-centered coordinates is debated. Here, I review behavioral, neuropsychological, neurophysiological (neuronal recording), and neuroimaging evidence for and against allocentric, object-centered, or world-centered spatial reference frames. Based on theoretical considerations, simulations, and empirical findings from spatial navigation, spatial judgments, and goal-directed movements, I suggest that all spatial representations may in fact be dependent on egocentric reference frames. PMID:26696861
Fiehler, Katja; Wolf, Christian; Klinghammer, Mathias; Blohm, Gunnar
When interacting with our environment we generally make use of egocentric and allocentric object information by coding object positions relative to the observer or relative to the environment, respectively. Bayesian theories suggest that the brain integrates both sources of information optimally for perception and action. However, experimental evidence for egocentric and allocentric integration is sparse and has only been studied using abstract stimuli lacking ecological relevance. Here, we investigated the use of egocentric and allocentric information during memory-guided reaching to images of naturalistic scenes. Participants encoded a breakfast scene containing six objects on a table (local objects) and three objects in the environment (global objects). After a 2 s delay, a visual test scene reappeared for 1 s in which 1 local object was missing (= target) and of the remaining, 1, 3 or 5 local objects or one of the global objects were shifted to the left or to the right. The offset of the test scene prompted participants to reach to the target as precisely as possible. Only local objects served as potential reach targets and thus were task-relevant. When shifting objects we predicted accurate reaching if participants only used egocentric coding of object position and systematic shifts of reach endpoints if allocentric information were used for movement planning. We found that reaching movements were largely affected by allocentric shifts showing an increase in endpoint errors in the direction of object shifts with the number of local objects shifted. No effect occurred when one local or one global object was shifted. Our findings suggest that allocentric cues are indeed used by the brain for memory-guided reaching towards targets in naturalistic visual scenes. Moreover, the integration of egocentric and allocentric object information seems to depend on the extent of changes in the scene.
Fiehler, Katja; Wolf, Christian; Klinghammer, Mathias; Blohm, Gunnar
When interacting with our environment we generally make use of egocentric and allocentric object information by coding object positions relative to the observer or relative to the environment, respectively. Bayesian theories suggest that the brain integrates both sources of information optimally for perception and action. However, experimental evidence for egocentric and allocentric integration is sparse and has only been studied using abstract stimuli lacking ecological relevance. Here, we investigated the use of egocentric and allocentric information during memory-guided reaching to images of naturalistic scenes. Participants encoded a breakfast scene containing six objects on a table (local objects) and three objects in the environment (global objects). After a 2 s delay, a visual test scene reappeared for 1 s in which 1 local object was missing (= target) and of the remaining, 1, 3 or 5 local objects or one of the global objects were shifted to the left or to the right. The offset of the test scene prompted participants to reach to the target as precisely as possible. Only local objects served as potential reach targets and thus were task-relevant. When shifting objects we predicted accurate reaching if participants only used egocentric coding of object position and systematic shifts of reach endpoints if allocentric information were used for movement planning. We found that reaching movements were largely affected by allocentric shifts showing an increase in endpoint errors in the direction of object shifts with the number of local objects shifted. No effect occurred when one local or one global object was shifted. Our findings suggest that allocentric cues are indeed used by the brain for memory-guided reaching towards targets in naturalistic visual scenes. Moreover, the integration of egocentric and allocentric object information seems to depend on the extent of changes in the scene. PMID:25202252
Ramos, Juan M J
Two experiments examined the effects of perirhinal cortex and hippocampal neurotoxic lesions on the retention of allocentric information. Perirhinal (Expt. 1) and hippocampal rats (Expt. 2) were trained on an allocentric task until they reached a performance equal to that of the control groups. Results showed that 24 days after acquisition, during a retraining period, only the hippocampal rats presented a deficit in retention. These results suggest that the perirhinal cortex and the hippocampus can be functionally dissociated in terms of their participation in the formation of long-term spatial memory. Also, the allocentric spatial memory functions of the hippocampus seem not to depend on their afferent connections with the perirhinal cortex.
Serino, Silvia; Pedroli, Elisa; Keizer, Anouk; Triberti, Stefano; Dakanalis, Antonios; Pallavicini, Federica; Chirico, Alice; Riva, Giuseppe
An increasing amount of evidence has shown that embodiment of a virtual body via visuo-tactile stimulation can lead to an altered perception of body and object size. The current study aimed to investigate whether virtual reality (VR) body swapping can be an effective tool for modifying the enduring memory of the body. The experimental sample included 21 female participants who were asked to estimate the width and circumference of different body parts before any kind of stimulation and after two types of body swapping illusions ("synchronous visuo-tactile stimulation" and "asynchronous visuo-tactile stimulation"). Findings revealed that after participants embodied a virtual body with a skinny belly (independently of the type of visuo-tactile stimulation), there was an update of the stored representation of the body: participants reported a decrease in the ratio between estimated and actual body measures for most of the body parts considered. Based on the Allocentric Lock Theory, these findings provide first evidence that VR body swapping is able to induce a change in the memory of the body. This knowledge may be potentially useful for patients suffering from eating and weight disorders.
Ganesh, Shanti; van Schie, Hein T; Cross, Emily S; de Lange, Floris P; Wigboldus, Daniël H J
Mental imagery of one's body moving through space is important for imagining changing visuospatial perspectives, as well as for determining how we might appear to other people. Previous neuroimaging research has implicated the temporoparietal junction (TPJ) in this process. It is unclear, however, how neural activity in the TPJ relates to the rotation perspectives from which mental spatial transformation (MST) of one's own body can take place, i.e. from an egocentric or an allocentric perspective. It is also unclear whether TPJ involvement in MST is self-specific or whether the TPJ may also be involved in MST of other human bodies. The aim of the current study was to disentangle neural processes involved in egocentric versus allocentric MSTs of human bodies representing self and other. We measured functional brain activity of healthy participants while they performed egocentric and allocentric MSTs in relation to whole-body photographs of themselves and a same-sex stranger. Findings indicated higher blood oxygen level-dependent (BOLD) response in bilateral TPJ during egocentric versus allocentric MST. Moreover, BOLD response in the TPJ during egocentric MST correlated positively with self-report scores indicating how awkward participants felt while viewing whole-body photos of themselves. These findings considerably advance our understanding of TPJ involvement in MST and its interplay with self-awareness.
Byrne, Patrick; Becker, Suzanna; Burgess, Neil
The authors model the neural mechanisms underlying spatial cognition, integrating neuronal systems and behavioral data, and address the relationships between long-term memory, short-term memory, and imagery, and between egocentric and allocentric and visual and ideothetic representations. Long-term spatial memory is modeled as attractor dynamics…
Dupierrix, Eve; Hillairet de Boisferon, Anne; Barbeau, Emmanuel; Pascalis, Olivier
Although human infants demonstrate early competence to retain visual information, memory capacities during infancy remain largely undocumented. In three experiments, we used a Visual Paired Comparison (VPC) task to examine abilities to encode identity (Experiment 1) and spatial properties (Experiments 2a and 2b) of unfamiliar complex visual…
Banta Lavenex, Pamela; Lavenex, Pierre
Studies of the role of the monkey hippocampus in spatial learning and memory, however few, have reliably produced inconsistent results. Whereas the role of the hippocampus in spatial learning and memory has been clearly established in rodents, studies in nonhuman primates have made a variety of claims that range from the involvement of the hippocampus in spatial memory only at relatively longer memory delays, to no role for the hippocampus in spatial memory at all. In contrast, we have shown that selective damage restricted to the hippocampus (CA regions) prevents the learning or use of allocentric, spatial relational representations of the environment in freely behaving adult monkeys tested in an open-field arena. In this commentary, we discuss a unifying framework that explains these apparently discrepant results regarding the role of the monkey hippocampus in spatial learning and memory. We describe clear and strict criteria to interpret the findings from previous studies and guide future investigations of spatial memory in monkeys. Specifically, we affirm that, as in the rodent, the primate hippocampus is critical for spatial relational learning and memory, and in a time-independent manner. We describe how claims to the contrary are the result of experimental designs that fail to recognize, and control for, egocentric (hippocampus-independent) and allocentric (hippocampus-dependent) spatial frames of reference. Finally, we conclude that the available data demonstrate unequivocally that the central role of the hippocampus in allocentric, spatial relational learning and memory is conserved among vertebrates, including nonhuman primates.
Ainge, James A.; Langston, Rosamund F.
Spatial memory is a well-characterized psychological function in both humans and rodents. The combined computations of a network of systems including place cells in the hippocampus, grid cells in the medial entorhinal cortex and head direction cells found in numerous structures in the brain have been suggested to form the neural instantiation of the cognitive map as first described by Tolman in 1948. However, while our understanding of the neural mechanisms underlying spatial representations in adults is relatively sophisticated, we know substantially less about how this network develops in young animals. In this article we briefly review studies examining the developmental timescale that these systems follow. Electrophysiological recordings from very young rats show that directional information is at adult levels at the outset of navigational experience. The systems supporting allocentric memory, however, take longer to mature. This is consistent with behavioral studies of young rats which show that spatial memory based on head direction develops very early but that allocentric spatial memory takes longer to mature. We go on to report new data demonstrating that memory for associations between objects and their spatial locations is slower to develop than memory for objects alone. This is again consistent with previous reports suggesting that adult like spatial representations have a protracted development in rats and also suggests that the systems involved in processing non-spatial stimuli come online earlier. PMID:22403529
Thaler, Lore; Goodale, Melvyn A.
Neuropsychological evidence suggests that different brain areas may be involved in movements that are directed at visual targets (e.g., pointing or reaching), and movements that are based on allocentric visual information (e.g., drawing or copying). Here we used fMRI to investigate the neural correlates of these two types of movements in healthy volunteers. Subjects (n = 14) performed right hand movements in either a target-directed task (moving a cursor to a target dot) or an allocentric task (moving a cursor to reproduce the distance and direction between two distal target dots) with or without visual feedback about their hand movement. Movements were monitored with an MR compatible touch panel. A whole brain analysis revealed that movements in allocentric conditions led to an increase in activity in the fundus of the left intra-parietal sulcus (IPS), in posterior IPS, in bilateral dorsal premotor cortex (PMd), and in the lateral occipital complex (LOC). Visual feedback in both target-directed and allocentric conditions led to an increase in activity in area MT+, superior parietal–occipital cortex (SPOC), and posterior IPS (all bilateral). In addition, we found that visual feedback affected brain activity differently in target-directed as compared to allocentric conditions, particularly in the pre-supplementary motor area, PMd, IPS, and parieto-occipital cortex. Our results, in combination with previous findings, suggest that the LOC is essential for allocentric visual coding and that SPOC is involved in visual feedback control. The differences in brain activity between target-directed and allocentric visual feedback conditions may be related to behavioral differences in visual feedback control. Our results advance the understanding of the visual coordinate frame used by the LOC. In addition, because of the nature of the allocentric task, our results have relevance for the understanding of neural substrates of magnitude estimation and vector coding of
Thaler, Lore; Goodale, Melvyn A
Neuropsychological evidence suggests that different brain areas may be involved in movements that are directed at visual targets (e.g., pointing or reaching), and movements that are based on allocentric visual information (e.g., drawing or copying). Here we used fMRI to investigate the neural correlates of these two types of movements in healthy volunteers. Subjects (n = 14) performed right hand movements in either a target-directed task (moving a cursor to a target dot) or an allocentric task (moving a cursor to reproduce the distance and direction between two distal target dots) with or without visual feedback about their hand movement. Movements were monitored with an MR compatible touch panel. A whole brain analysis revealed that movements in allocentric conditions led to an increase in activity in the fundus of the left intra-parietal sulcus (IPS), in posterior IPS, in bilateral dorsal premotor cortex (PMd), and in the lateral occipital complex (LOC). Visual feedback in both target-directed and allocentric conditions led to an increase in activity in area MT+, superior parietal-occipital cortex (SPOC), and posterior IPS (all bilateral). In addition, we found that visual feedback affected brain activity differently in target-directed as compared to allocentric conditions, particularly in the pre-supplementary motor area, PMd, IPS, and parieto-occipital cortex. Our results, in combination with previous findings, suggest that the LOC is essential for allocentric visual coding and that SPOC is involved in visual feedback control. The differences in brain activity between target-directed and allocentric visual feedback conditions may be related to behavioral differences in visual feedback control. Our results advance the understanding of the visual coordinate frame used by the LOC. In addition, because of the nature of the allocentric task, our results have relevance for the understanding of neural substrates of magnitude estimation and vector coding of
Wen, Wen; Ishikawa, Toru; Sato, Takao
This study examined how different components of working memory are involved in the acquisition of egocentric and allocentric survey knowledge by people with a good and poor sense of direction (SOD). We employed a dual-task method and asked participants to learn routes from videos with verbal, visual, and spatial interference tasks and without any…
Gagnon, Stephanie A; Brunyé, Tad T; Gardony, Aaron; Noordzij, Matthijs L; Mahoney, Caroline R; Taylor, Holly A
Learning a novel environment involves integrating first-person perceptual and motoric experiences with developing knowledge about the overall structure of the surroundings. The present experiments provide insights into the parallel development of these egocentric and allocentric memories by intentionally conflicting body- and world-centered frames of reference during learning, and measuring outcomes via online and offline measures. Results of two experiments demonstrate faster learning and increased memory flexibility following route perspective reading (Experiment 1) and virtual navigation (Experiment 2) when participants begin exploring the environment on a northward (vs. any other direction) allocentric heading. We suggest that learning advantages due to aligning body-centered (left/right/forward/back) with world-centered (NSEW) reference frames are indicative of three features of spatial memory development and representation. First, memories for egocentric and allocentric information develop in parallel during novel environment learning. Second, cognitive maps have a preferred orientation relative to world-centered coordinates. Finally, this preferred orientation corresponds to traditional orientation of physical maps (i.e., north is upward), suggesting strong associations between daily perceptual and motor experiences and the manner in which we preferentially represent spatial knowledge.
Ciaramelli, Elisa; Rosenbaum, R Shayna; Solcz, Stephanie; Levine, Brian; Moscovitch, Morris
The ability to navigate in a familiar environment depends on both an intact mental representation of allocentric spatial information and the integrity of systems supporting complementary egocentric representations. Although the hippocampus has been implicated in learning new allocentric spatial information, converging evidence suggests that the posterior parietal cortex (PPC) might support egocentric representations. To date, however, few studies have examined long-standing egocentric representations of environments learned long ago. Here we tested 7 patients with focal lesions in PPC and 12 normal controls in remote spatial memory tasks, including 2 tasks reportedly reliant on allocentric representations (distance and proximity judgments) and 2 tasks reportedly reliant on egocentric representations (landmark sequencing and route navigation; see Rosenbaum, Ziegler, Winocur, Grady, & Moscovitch, 2004). Patients were unimpaired in distance and proximity judgments. In contrast, they all failed in route navigation, and left-lesioned patients also showed marginally impaired performance in landmark sequencing. Patients' subjective experience associated with navigation was impoverished and disembodied compared with that of the controls. These results suggest that PPC is crucial for accessing remote spatial memories within an egocentric reference frame that enables both navigation and reexperiencing. Additionally, PPC was found to be necessary to implement specific aspects of allocentric navigation with high demands on spontaneous retrieval.
Winocur, Gordon; Moscovitch, Morris; Rosenbaum, R Shayna; Sekeres, Melanie
The effect of aging on remote spatial memory was tested in a group of 2-year-old rats (VR-O) that, as young adults, were reared for 3 months in a complex 'village' environment. The VR-O rats exhibited significant savings in finding the locations of specific reward compartments within the village, relative to a group of old rats (VNR-O) experiencing the village for the first time. The VNR-O rats were also impaired, relative to naive young rats, in learning the reward locations. Probe tests indicated that the VR-O rats retained allocentric spatial memory for the environment and were not using sensory or other non-spatial cues to guide behaviour. Overall, the results indicate that the aged rats experienced a decline in the ability to learn and remember detailed spatial relationships and that the VR-O group's successful performance on the remote spatial memory test was guided by a form of schematic memory that captured the essential features of the village environment. The potential contribution of the hippocampus to the pattern of lost and spared learning and memory observed in the aged rats was discussed.
Banta Lavenex, Pamela; Boujon, Valérie; Ndarugendamwo, Angélique; Lavenex, Pierre
Here, we aimed to determine the capacity of human short-term memory for allocentric spatial information in a real-world setting. Young adults were tested on their ability to learn, on a trial-unique basis, and remember over a 1-min interval the location(s) of 1, 3, 5, or 7 illuminating pads, among 23 pads distributed in a 4m×4m arena surrounded by curtains on three sides. Participants had to walk to and touch the pads with their foot to illuminate the goal locations. In contrast to the predictions from classical slot models of working memory capacity limited to a fixed number of items, i.e., Miller's magical number 7 or Cowan's magical number 4, we found that the number of visited locations to find the goals was consistently about 1.6 times the number of goals, whereas the number of correct choices before erring and the number of errorless trials varied with memory load even when memory load was below the hypothetical memory capacity. In contrast to resource models of visual working memory, we found no evidence that memory resources were evenly distributed among unlimited numbers of items to be remembered. Instead, we found that memory for even one individual location was imprecise, and that memory performance for one location could be used to predict memory performance for multiple locations. Our findings are consistent with a theoretical model suggesting that the precision of the memory for individual locations might determine the capacity of human short-term memory for spatial information.
Street, Whitney N.; Wang, Ranxiao Frances
The perspective-taking task is one of the most common paradigms used to study the nature of spatial memory, and better performance for certain orientations is generally interpreted as evidence of spatial representations using these reference directions. However, performance advantages can also result from the relative ease in certain…
Kerster, Bryan E; Rhodes, Theo; Kello, Christopher T
Foraging and foraging-like processes are found in spatial navigation, memory, visual search, and many other search functions in human cognition and behavior. Foraging is commonly theorized using either random or correlated movements based on Lévy walks, or a series of decisions to remain or leave proximal areas known as "patches". Neither class of model makes use of spatial memory, but search performance may be enhanced when information about searched and unsearched locations is encoded. A video game was developed to test the role of human spatial memory in a canonical foraging task. Analyses of search trajectories from over 2000 human players yielded evidence that foraging movements were inherently clustered, and that clustering was facilitated by spatial memory cues and influenced by memory for spatial locations of targets found. A simple foraging model is presented in which spatial memory is used to integrate aspects of Lévy-based and patch-based foraging theories to perform a kind of area-restricted search, and thereby enhance performance as search unfolds. Using only two free parameters, the model accounts for a variety of findings that individually support competing theories, but together they argue for the integration of spatial memory into theories of foraging.
Burgess, Neil; Spiers, Hugo J.; Paleologou, Eleni
Subjects in a darkroom saw an array of five phosphorescent objects on a circular table and, after a short delay, indicated which object had been moved. During the delay the subject, the table or a phosphorescent landmark external to the array was moved (a rotation about the centre of the table) either alone or together. The subject then had to…
Kaufman, Miron; Allen, P.
We develop and test a thermodynamic model of spatial memory. Our model is an application of statistical thermodynamics to cognitive science. It is related to applications of the statistical mechanics framework in parallel distributed processes research. Our macroscopic model allows us to evaluate an entropy associated with spatial memory tasks. We find that older adults exhibit higher levels of entropy than younger adults. Thurstone's Law of Categorical Judgment, according to which the discriminal processes along the psychological continuum produced by presentations of a single stimulus are normally distributed, is explained by using a Hooke spring model of spatial memory. We have also analyzed a nonlinear modification of the ideal spring model of spatial memory. This work is supported by NIH/NIA grant AG09282-06.
De Jaeger, Xavier; Courtey, Julie; Brus, Maïna; Artinian, Julien; Villain, Hélène; Bacquié, Elodie; Roullet, Pascal
Reconsolidation is necessary for the restabilization of reactivated memory traces. However, experimental parameters have been suggested as boundary conditions for this process. Here we investigated the role of a spatial memory trace's age, strength, and update on the reconsolidation process in mice. We first found that protein synthesis is…
Ladage, L D; Roth, T C; Cerjanic, A M; Sinervo, B; Pravosudov, V V
In many animals, behaviours such as territoriality, mate guarding, navigation and food acquisition rely heavily on spatial memory abilities; this has been demonstrated in diverse taxa, from invertebrates to mammals. However, spatial memory ability in squamate reptiles has been seen as possible, at best, or non-existent, at worst. Of the few previous studies testing for spatial memory in squamates, some have found no evidence of spatial memory while two studies have found evidence of spatial memory in snakes, but have been criticized based on methodological issues. We used the Barnes maze, a common paradigm to test spatial memory abilities in mammals, to test for spatial memory abilities in the side-blotched lizard (Uta stansburiana). We found the existence of spatial memory in this species using this spatial task. Thus, our study supports the existence of spatial memory in this squamate reptile species and seeks to parsimoniously align this species with the diverse taxa that demonstrate spatial memory ability.
Greene, E; Naranjo, J N
The contribution of structures in the limbic diencephalon to spatial memory function was investigated. Rats with lesions of either the anteroventral thalamus, anteromedial thalamus, dorsomedial thalamus or mammillary bodies were compared in their ability to perform a delayed alternation task. The results indicate the ablation of the thalamic nuclei did not impair delayed-alternation memory, but there was impairment following damage to the mammillary bodies. Placement of the discrete lesions was verified using Nissl sections and by tracing the pattern of projections using a silver degeneration stain. The results suggest that individual thalamic nuclei are not essential in the storage and/or retrieval of spatial memory. The data are discussed in terms of spatial deficits resulting from damage to the hippocampus proper or to the pathways connecting it to other brain structures.
Ciaramelli, Elisa; Rosenbaum, R. Shayna; Solcz, Stephanie; Levine, Brian; Moscovitch, Morris
The ability to navigate in a familiar environment depends on both an intact mental representation of allocentric spatial information and the integrity of systems supporting complementary egocentric representations. Although the hippocampus has been implicated in learning new allocentric spatial information, converging evidence suggests that the…
Rosenbaum, R. Shayna; Cassidy, Benjamin N.; Herdman, Katherine A.
The hippocampus is believed to have evolved to support allocentric spatial representations of environments as well as the details of personal episodes that occur within them, whereas other brain structures are believed to support complementary egocentric spatial representations. Studies of patients with adult-onset lesions lend support to these distinctions for newly encountered places but suggest that with time and/or experience, schematic aspects of environments can exist independent of the hippocampus. Less clear is the quality of spatial memories acquired in individuals with impaired episodic memory in the context of a hippocampal system that did not develop normally. Here we describe a detailed investigation of the integrity of spatial representations of environments navigated repeatedly over many years in the rare case of H.C., a person with congenital absence of the mammillary bodies and abnormal hippocampal and fornix development. H.C. and controls who had extensive experience navigating the residential and downtown areas known to H.C. were tested on mental navigation tasks that assess the identity, location, and spatial relations among landmarks, and the ability to represent routes. H.C. was able to represent distances and directions between familiar landmarks and provide accurate, though inefficient, route descriptions. However, difficulties producing detailed spatial features on maps and accurately ordering more than two landmarks that are in close proximity to one another along a route suggest a spatial representation that includes only coarse, schematic information that lacks coherence and that cannot be used flexibly. This pattern of performance is considered in the context of other areas of preservation and impairment exhibited by H.C. and suggests that the allocentric-egocentric dichotomy with respect to hippocampal and extended hippocampal system function may need to be reconsidered. PMID:26029074
Tavassoli, Nader T.
Investigated spatial memory for written words as a behavioral consequence of verbal processing differences. Across three experiments with Chinese and U.S. college students, spatial memory for real and nonsense words was greater for Chinese logographs than for alphabetic English words. This spatial memory advantage was absent for pictures and…
Belmonti, Vittorio; Cioni, Giovanni; Berthoz, Alain
Navigational and reaching spaces are known to involve different cognitive strategies and brain networks, whose development in humans is still debated. In fact, high-level spatial processing, including allocentric location encoding, is already available to very young children, but navigational strategies are not mature until late childhood. The Magic Carpet (MC) is a new electronic device translating the traditional Corsi Block-tapping Test (CBT) to navigational space. In this study, the MC and the CBT were used to assess spatial memory for navigation and for reaching, respectively. Our hypothesis was that school-age children would not treat MC stimuli as navigational paths, assimilating them to reaching sequences. Ninety-one healthy children aged 6 to 11 years and 18 adults were enrolled. Overall short-term memory performance (span) on both tests, effects of sequence geometry, and error patterns according to a new classification were studied. Span increased with age on both tests, but relatively more in navigational than in reaching space, particularly in males. Sequence geometry specifically influenced navigation, not reaching. The number of body rotations along the path affected MC performance in children more than in adults, and in women more than in men. Error patterns indicated that navigational sequences were increasingly retained as global paths across development, in contrast to separately stored reaching locations. A sequence of spatial locations can be coded as a navigational path only if a cognitive switch from a reaching mode to a navigation mode occurs. This implies the integration of egocentric and allocentric reference frames, of visual and idiothetic cues, and access to long-term memory. This switch is not yet fulfilled at school age due to immature executive functions.
Hebscher, Melissa; Levine, Brian; Gilboa, Asaf
Spatial information is a central aspect of episodic autobiographical memory (EAM). Space-based theories of memory, including cognitive map and scene construction models, posit that spatial reinstatement is a required process during early event recall. Spatial information can be represented from both allocentric (third-person) and egocentric (first-person) perspectives during EAM, with egocentric perspectives being important for mental imagery and supported by the precuneus. Individuals differ in their tendency to rely on allocentric or egocentric information, and in general, the subjective experience of remembering in EAM differs greatly across individuals. Here we examined individual differences in spatial aspects of EAM, how such differences influence the vividness and temporal order of recollection, and their anatomical correlates. We cued healthy young participants (n =63) with personally familiar locations and non-locations. We examined how cue type affects (i) retrieval dynamics and (ii) phenomenological aspects of remembering, and related behavioural performance to regional brain volumes (n =42). Participants tended to spontaneously recall spatial information early during recollection, even in the absence of spatial cues, and individuals with a stronger tendency to recall space first also displayed faster reaction times. Across participants, place-cued memories were re-experienced more vividly and were richer in detail than those cued by objects, but not more than those cued by familiar persons. Volumetric differences were associated with behavioural performance such that egocentric remembering was positively associated with precuneus volume. Hippocampal CA2/CA3 volumes were associated with the tendency to recall place-cued memories less effortfully. Consistent with scene construction theories, this study suggests that spatial information is reinstated early and contributes to the efficiency and phenomenology of EAM. However, early recall of spatial
Crystal, Jonathon D.; Babb, Stephanie J.
We investigated the time course of spatial-memory decay in rats using an eight-arm radial maze. It is well established that performance remains high with retention intervals as long as 4 h, but declines to chance with a 24-h retention interval (Beatty, W. W., & Shavalia, D. A. (1980b). Spatial memory in rats: time course of working memory and…
Moscovitch, Morris; Rosenbaum, R Shayna; Gilboa, Asaf; Addis, Donna Rose; Westmacott, Robyn; Grady, Cheryl; McAndrews, Mary Pat; Levine, Brian; Black, Sandra; Winocur, Gordon; Nadel, Lynn
We review lesion and neuroimaging evidence on the role of the hippocampus, and other structures, in retention and retrieval of recent and remote memories. We examine episodic, semantic and spatial memory, and show that important distinctions exist among different types of these memories and the structures that mediate them. We argue that retention and retrieval of detailed, vivid autobiographical memories depend on the hippocampal system no matter how long ago they were acquired. Semantic memories, on the other hand, benefit from hippocampal contribution for some time before they can be retrieved independently of the hippocampus. Even semantic memories, however, can have episodic elements associated with them that continue to depend on the hippocampus. Likewise, we distinguish between experientially detailed spatial memories (akin to episodic memory) and more schematic memories (akin to semantic memory) that are sufficient for navigation but not for re-experiencing the environment in which they were acquired. Like their episodic and semantic counterparts, the former type of spatial memory is dependent on the hippocampus no matter how long ago it was acquired, whereas the latter can survive independently of the hippocampus and is represented in extra-hippocampal structures. In short, the evidence reviewed suggests strongly that the function of the hippocampus (and possibly that of related limbic structures) is to help encode, retain, and retrieve experiences, no matter how long ago the events comprising the experience occurred, and no matter whether the memories are episodic or spatial. We conclude that the evidence favours a multiple trace theory (MTT) of memory over two other models: (1) traditional consolidation models which posit that the hippocampus is a time-limited memory structure for all forms of memory; and (2) versions of cognitive map theory which posit that the hippocampus is needed for representing all forms of allocentric space in memory. PMID
Steele, Shelly D.; Minshew, Nancy J.; Luna, Beatriz; Sweeney, John A.
Previous studies have reported working memory deficits in autism, but this finding has been inconsistent. One possibility is that deficits in this domain may be present only when working memory load exceeds some limited capacity. High-functioning individuals with autism performed the CANTAB computerized test of spatial working memory. Individuals…
Vann, Seralynne D; Albasser, Mathieu M
Recognition and spatial memory are typically associated with the perirhinal cortex and hippocampal formation, respectively. Solely focusing on these structures for these specific mnemonic functions may, however, be limiting progress in the field. The distinction between these subdivisions of memory is becoming less defined as, for example, hippocampal cells traditionally considered to encode locations also encode place-object associations. There is increasing evidence for the involvement of overlapping networks of brain structures for aspects of both spatial and recognition memory. Future models of spatial and recognition memory will have to extend beyond the hippocampus and perirhinal cortex to incorporate a wider network of cortical and subcortical structures.
Ferretti, Valentina; Roullet, Pascal; Sargolini, Francesca; Rinaldi, Arianna; Perri, Valentina; Del Fabbro, Martina; Costantini, Vivian J A; Annese, Valentina; Scesa, Gianluigi; De Stefano, Maria Egle; Oliverio, Alberto; Mele, Andrea
Spatial memory formation is a dynamic process requiring a series of cellular and molecular steps, such as gene expression and protein translation, leading to morphological changes that have been envisaged as the structural bases for the engram. Despite the role suggested for medial temporal lobe plasticity in spatial memory, recent behavioral observations implicate specific components of the striatal complex in spatial information processing. However, the potential occurrence of neural plasticity within this structure after spatial learning has never been investigated. In this study we demonstrate that blockade of cAMP response element binding protein-induced transcription or inhibition of protein synthesis or extracellular proteolytic activity in the ventral striatum impairs long-term spatial memory. These findings demonstrate that, in the ventral striatum, similarly to what happens in the hippocampus, several key molecular events crucial for the expression of neural plasticity are required in the early stages of spatial memory formation.
Ferretti, Valentina; Roullet, Pascal; Sargolini, Francesca; Rinaldi, Arianna; Perri, Valentina; Del Fabbro, Martina; Costantini, Vivian J. A.; Annese, Valentina; Scesa, Gianluigi; De Stefano, Maria Egle; Oliverio, Alberto; Mele, Andrea
Spatial memory formation is a dynamic process requiring a series of cellular and molecular steps, such as gene expression and protein translation, leading to morphological changes that have been envisaged as the structural bases for the engram. Despite the role suggested for medial temporal lobe plasticity in spatial memory, recent behavioral observations implicate specific components of the striatal complex in spatial information processing. However, the potential occurrence of neural plasticity within this structure after spatial learning has never been investigated. In this study we demonstrate that blockade of cAMP response element binding protein–induced transcription or inhibition of protein synthesis or extracellular proteolytic activity in the ventral striatum impairs long-term spatial memory. These findings demonstrate that, in the ventral striatum, similarly to what happens in the hippocampus, several key molecular events crucial for the expression of neural plasticity are required in the early stages of spatial memory formation. PMID:20351272
Gagnon, Stephanie A.; Brunyé, Tad T.; Gardony, Aaron; Noordzij, Matthijs L.; Mahoney, Caroline R.; Taylor, Holly A.
Learning a novel environment involves integrating first-person perceptual and motoric experiences with developing knowledge about the overall structure of the surroundings. The present experiments provide insights into the parallel development of these egocentric and allocentric memories by intentionally conflicting body- and world-centered frames…
Jones, Bethany; Bukoski, Elizabeth; Nadel, Lynn; Fellous, Jean-Marc
There is strong evidence that reactivation of a memory returns it to a labile state, initiating a restabilization process termed reconsolidation, which allows for updating of the memory. In this study we investigated reactivation-dependent updating using a new positively motivated spatial task in rodents that was designed specifically to model a…
Barkas, Lisa; Redhead, Edward; Taylor, Matthew; Shtaya, Anan; Hamilton, Derek A.; Gray, William P.
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,…
Koehl, Muriel; Ichas, François; De Giorgi, Francesca; Costet, Pierre; Abrous, Djoher Nora; Piazza, Pier Vincenzo
The dentate gyrus of the hippocampus is one of the few regions of the mammalian brain where new neurons are generated throughout adulthood. This adult neurogenesis has been proposed as a novel mechanism that mediates spatial memory. However, data showing a causal relationship between neurogenesis and spatial memory are controversial. Here, we developed an inducible transgenic strategy allowing specific ablation of adult-born hippocampal neurons. This resulted in an impairment of spatial relational memory, which supports a capacity for flexible, inferential memory expression. In contrast, less complex forms of spatial knowledge were unaltered. These findings demonstrate that adult-born neurons are necessary for complex forms of hippocampus-mediated learning. PMID:18509506
Pine, Daniel S; Grun, Joseph; Maguire, Eleanor A; Burgess, Neil; Zarahn, Eric; Koda, Vivian; Fyer, Abby; Szeszko, Philip R; Bilder, Robert M
Navigation in spatial contexts has been studied in diverse species, yielding insights into underlying neural mechanisms and their phylogenetic progression. Spatial navigation in humans is marked by age-related changes that may carry important implications for understanding cortical development. The emergence of "allocentric" processing, reflecting that ability to use viewer-independent spatial abstractions, represents an important developmental change. We used fMRI to map brain regions engaged during memory-guided navigation in a virtual reality environment in adolescents and adults. Blood oxygen level-dependent (BOLD) signal was monitored in eight adolescents and eight adults in a 1.5-T MRI scanner during three conditions: (1) memory-guided navigation (NAV); (2) arrow-guided navigation (ARROW); and (3) fixation (FIX). We quantified navigation ability during scanning and allocentric memory after scanning, based on subjects' ability to label a previously unseen, aerial view of the town. Adolescents and adults exhibited similar memory-guided navigation ability, but adults exhibited superior allocentric memory ability. Memory-guided navigation ability during scanning correlated with BOLD change between NAV/ARROWS in various regions, including a right frontal and right-anterior medial temporal lobe region. Age group and allocentric memory together explained significant variance in BOLD change in temporoparietal association cortex and the cerebellum, particularly in the left hemisphere. Consistent with developmental models, these findings relate maturation in the coding of spatial information to functional changes in a distributed, left-lateralized neural network.
Fagan, William F; Lewis, Mark A; Auger-Méthé, Marie; Avgar, Tal; Benhamou, Simon; Breed, Greg; LaDage, Lara; Schlägel, Ulrike E; Tang, Wen-wu; Papastamatiou, Yannis P; Forester, James; Mueller, Thomas
Memory is critical to understanding animal movement but has proven challenging to study. Advances in animal tracking technology, theoretical movement models and cognitive sciences have facilitated research in each of these fields, but also created a need for synthetic examination of the linkages between memory and animal movement. Here, we draw together research from several disciplines to understand the relationship between animal memory and movement processes. First, we frame the problem in terms of the characteristics, costs and benefits of memory as outlined in psychology and neuroscience. Next, we provide an overview of the theories and conceptual frameworks that have emerged from behavioural ecology and animal cognition. Third, we turn to movement ecology and summarise recent, rapid developments in the types and quantities of available movement data, and in the statistical measures applicable to such data. Fourth, we discuss the advantages and interrelationships of diverse modelling approaches that have been used to explore the memory-movement interface. Finally, we outline key research challenges for the memory and movement communities, focusing on data needs and mathematical and computational challenges. We conclude with a roadmap for future work in this area, outlining axes along which focused research should yield rapid progress.
Zhang, Hui; Mou, Weimin; McNamara, Timothy P.; Wang, Lin
Four experiments investigated the manner in which people use spatial reference directions to organize spatial memories of 2 conceptually nested layouts. Participants learned directions of 8 remote cities centered to Beijing or Edmonton, where the experiments occurred, using a map or using direct pointing. The map and the environment were aligned,…
Belmonti, Vittorio; Cioni, Giovanni; Berthoz, Alain
Navigational and reaching spaces are known to involve different cognitive strategies and brain networks, whose development in humans is still debated. In fact, high-level spatial processing, including allocentric location encoding, is already available to very young children, but navigational strategies are not mature until late childhood. The…
Rodríguez, F; López, J C; Vargas, J P; Broglio, C; Gómez, Y; Salas, C
The forebrain of vertebrates shows great morphological variation and specialized adaptations. However, an increasing amount of neuroanatomical and functional data reveal that the evolution of the vertebrate forebrain could have been more conservative than previously realized. For example, the pallial region of the teleost telencephalon contains subdivisions presumably homologous with various pallial areas in amniotes, including possibly a homologue of the medial pallium or hippocampus. In mammals and birds, the hippocampus is critical for encoding complex spatial information to form map-like cognitive representations of the environment. Here, we present data showing that the pallial areas of reptiles and fish, previously proposed as homologous to the hippocampus of mammals and birds on an anatomical basis, are similarly involved in spatial memory and navigation by map-like or relational representations of the allocentric space. These data suggest that early in vertebrate evolution, the medial pallium of an ancestral fish group that gave rise to the extant vertebrates became specialized for processing and encoding complex spatial information, and that this functional trait has been retained through the evolution of each independent vertebrate lineage.
Meneghetti, Chiara; Gyselinck, Valerie; Pazzaglia, Francesca; De Beni, Rossana
The present study investigates the relation between spatial ability and visuo-spatial and verbal working memory in spatial text processing. In two experiments, participants listened to a spatial text (Experiments 1 and 2) and a non-spatial text (Experiment 1), at the same time performing a spatial or a verbal concurrent task, or no secondary task.…
Beaudet, Gregory; Bouet, Valentine; Jozet-Alves, Christelle; Schumann-Bard, Pascale; Dauphin, François; Paizanis, Eleni; Boulouard, Michel; Freret, Thomas
Elderly persons often face biological, psychological or social changes over time that may cause discomfort or morbidity. While some cognitive domains remain stable over time, others undergo a decline. Spatial navigation is a complex cognitive function essential for independence, safety and quality of life. While egocentric (body-centered) navigation is quite preserved during aging, allocentric (externally-centered) navigation—based on a cognitive map using distant landmarks—declines with age. Recent preclinical studies showed that serotonergic 5-HT7 receptors are localized in brain regions associated with allocentric spatial navigation processing. Behavioral assessments with pharmacological or genetic tools have confirmed the role of 5-HT7 receptors in allocentric navigation. Moreover, few data suggested a selective age-related decrease in the expression of 5-HT7 receptors in pivotal brain structures implicated in allocentric navigation such as the hippocampal CA3 region. We aim to provide a short overview of the potential role of 5-HT7 receptors in spatial navigation, and to argue for their interests as therapeutic targets against age-related cognitive decline. PMID:25642173
Beaudet, Gregory; Bouet, Valentine; Jozet-Alves, Christelle; Schumann-Bard, Pascale; Dauphin, François; Paizanis, Eleni; Boulouard, Michel; Freret, Thomas
Elderly persons often face biological, psychological or social changes over time that may cause discomfort or morbidity. While some cognitive domains remain stable over time, others undergo a decline. Spatial navigation is a complex cognitive function essential for independence, safety and quality of life. While egocentric (body-centered) navigation is quite preserved during aging, allocentric (externally-centered) navigation-based on a cognitive map using distant landmarks-declines with age. Recent preclinical studies showed that serotonergic 5-HT7 receptors are localized in brain regions associated with allocentric spatial navigation processing. Behavioral assessments with pharmacological or genetic tools have confirmed the role of 5-HT7 receptors in allocentric navigation. Moreover, few data suggested a selective age-related decrease in the expression of 5-HT7 receptors in pivotal brain structures implicated in allocentric navigation such as the hippocampal CA3 region. We aim to provide a short overview of the potential role of 5-HT7 receptors in spatial navigation, and to argue for their interests as therapeutic targets against age-related cognitive decline.
Cassilhas, Ricardo C; Tufik, Sergio; de Mello, Marco Túlio
There has long been discussion regarding the positive effects of physical exercise on brain activity. However, physical exercise has only recently begun to receive the attention of the scientific community, with major interest in its effects on the cognitive functions, spatial learning and memory, as a non-drug method of maintaining brain health and treating neurodegenerative and/or psychiatric conditions. In humans, several studies have shown the beneficial effects of aerobic and resistance exercises in adult and geriatric populations. More recently, studies employing animal models have attempted to elucidate the mechanisms underlying neuroplasticity related to physical exercise-induced spatial learning and memory improvement, even under neurodegenerative conditions. In an attempt to clarify these issues, the present review aims to discuss the role of physical exercise in the improvement of spatial learning and memory and the cellular and molecular mechanisms involved in neuroplasticity.
Fox, Jeffrey; Riccio, Mark; Hua, Fei; Bodenschatz, Eberhard; Gilmour, Robert
Beat-to-beat alternation of cardiac electrical properties (alternans) commonly occurs during rapid periodic pacing. Although alternans is generally associated with a resititution curve with slope >=1, recent studies by Gauthier and co-workers reported the absence of alternans in frog heart tissue with a restitution curve of slope >=1. These experimental findings were understood in terms of a memory model in which the duration D of an action potential depends on the preceding rest interval I as well as a memory variable M that accumulates during D and dissipates during I. We study the spatiotemporal dynamics of a spatially extended 1-d fiber using an ionic model that exhibits memory effects. We find that while a single cell can have a restitution slope >=1 and not show alternans (because of memory), the spatially extended system exhibits alternans. To understand the dynamical mechanism of this behavior, we study a coupled maps memory model both numerically and analytically. These results illustrate that spatial effects and memory effects can play a significant role in determining the dynamics of wave propagation in cardiac tissue.
Qiming Hou; Xin Sun; Kun Zhou; Lauterbach, C; Manocha, D
Recent GPU algorithms for constructing spatial hierarchies have achieved promising performance for moderately complex models by using the breadth-first search (BFS) construction order. While being able to exploit the massive parallelism on the GPU, the BFS order also consumes excessive GPU memory, which becomes a serious issue for interactive applications involving very complex models with more than a few million triangles. In this paper, we propose to use the partial breadth-first search (PBFS) construction order to control memory consumption while maximizing performance. We apply the PBFS order to two hierarchy construction algorithms. The first algorithm is for kd-trees that automatically balances between the level of parallelism and intermediate memory usage. With PBFS, peak memory consumption during construction can be efficiently controlled without costly CPU-GPU data transfer. We also develop memory allocation strategies to effectively limit memory fragmentation. The resulting algorithm scales well with GPU memory and constructs kd-trees of models with millions of triangles at interactive rates on GPUs with 1 GB memory. Compared with existing algorithms, our algorithm is an order of magnitude more scalable for a given GPU memory bound. The second algorithm is for out-of-core bounding volume hierarchy (BVH) construction for very large scenes based on the PBFS construction order. At each iteration, all constructed nodes are dumped to the CPU memory, and the GPU memory is freed for the next iteration's use. In this way, the algorithm is able to build trees that are too large to be stored in the GPU memory. Experiments show that our algorithm can construct BVHs for scenes with up to 20 M triangles, several times larger than previous GPU algorithms.
Chan, Dennis; Gallaher, Laura Marie; Moodley, Kuven; Minati, Ludovico; Burgess, Neil; Hartley, Tom
This protocol describes the administration of the 4 Mountains Test (4MT), a short test of spatial memory, in which memory for the topographical layout of four mountains within a computer-generated landscape is tested using a delayed match-to-sample paradigm. Allocentric spatial memory is assessed by altering the viewpoint, colors and textures between the initially presented and target images. Allocentric spatial memory is a key function of the hippocampus, one of the earliest brain regions to be affected in Alzheimer's disease (AD) and impairment of hippocampal function predates the onset of dementia. It was hypothesized that performance on the 4MT would aid the diagnosis of predementia AD, which manifests clinically as Mild Cognitive Impairment (MCI). The 4MT was applied to patients with MCI, stratified further based on cerebrospinal fluid (CSF) AD biomarker status (10 MCI biomarker positive, 9 MCI biomarker negative), and with mild AD dementia, as well as healthy controls. Comparator tests included tests of episodic memory and attention widely accepted as sensitive measures of early AD. Behavioral data were correlated with quantitative MRI measures of the hippocampus, precuneus and posterior cingulate gyrus. 4MT scores were significantly different between the two MCI groups (p = 0.001), with a test score of ≤8/15 associated with 100% sensitivity and 78% specificity for the classification of MCI with positive AD biomarkers, i.e., predementia AD. 4MT test scores correlated with hippocampal volume (r = 0.42) and cortical thickness of the precuneus (r = 0.55). In conclusion, the 4MT is effective in identifying the early stages of AD. The short duration, easy application and scoring, and favorable psychometric properties of the 4MT fulfil the need for a simple but accurate diagnostic test for predementia AD. PMID:27768046
Chieffi, S; Allport, D A
The organization of manual reaching movements suggests considerable independence in the initial programming with respect to the direction and the distance of the intended movement. It was hypothesized that short-term memory for a visually-presented location within reaching space, in the absence of other allocentric reference points, might also be represented in a motoric code, showing similar independence in the encoding of direction and distance. This hypothesis was tested in two experiments, using adult human subjects who were required to remember the location of a briefly presented luminous spot. Stimuli were presented in the dark, thus providing purely egocentric spatial information. After the specified delay, subjects were instructed to point to the remembered location. In Exp. 1, temporal decay of location memory was studied, over a range of 4-30 s. The results showed that (a) memory for both the direction and the distance of the visual target location declined over time, at about the same rate for both parameters; however, (b) errors of distance were much greater in the left than in the right hemispace, whereas direction errors showed no such effect; (c) the distance and direction errors were essentially uncorrelated, at all delays. These findings suggest independent representation of these two parameters in working memory. In Exp. 2 the subjects were required to remember the locations of two visual stimuli presented sequentially, one after the other. Only after both stimuli had been presented did the subject receive a signal from the experimenter as to which one was to be pointed to. The results showed that the encoding of a second location selectively interfered with memory for the direction but not for the distance of the to-be-remembered target location. As in Exp. 1, direction and distance errors were again uncorrelated. The results of both experiments indicate that memory for egocentrically-specified visual locations can encode the direction and
Miller, Jonathan F.; Lazarus, Eben M.; Polyn, Sean M.; Kahana, Michael J.
In recalling a list of previously experienced items, participants are known to organize their responses on the basis of the items' semantic and temporal similarities. Here, we examine how spatial information influences the organization of responses in free recall. In Experiment 1, participants studied and subsequently recalled lists of landmarks.…
Klauer, Karl Christoph; Zhao, Zengmei
A visual short-term memory task was more strongly disrupted by visual than spatial interference, and a spatial memory task was simultaneously more strongly disrupted by spatial than visual interference. This double dissociation supports a fractionation of visuospatial short-term memory into separate visual and spatial components. In 6 experiments,…
Tlauka, Michael; Clark, C. Richard; Liu, Ping; Conway, Marie
This study examined the temporal characteristics of event-related brain electrical activity associated with the processing of spatial memories derived from linguistic and tactile information. Participants learned a map by (1) reading a text description of the map, (2) touching a wooden topological representation of the map (hidden from view), or…
Xavier, Patrick; Chen, Michael C.; Hart, Brian; Hart, Derek; Lippitt, Carl; Wolfenbarger, Paul; Waymire, Russel
The SCREAM (Sandia Cognitive Runtime Engine with Active memory) software implements a subset of a Cognitive Famework developed at Sandia National Laboratories. The software is implemented in the Umbra simulation and modular software framework, which is C++-based. SCREAM components include a Concept Instance Driver, Semantic Activation Network, Concept Database, Context Recognizer, Context Database, Episodic Memory, Egocentric Spatial Memory, Allocentric Spatial Memory, Comparator, and a Context to Abstract Action converter. At initialization, modules load the data files that together specify all the components of a particular cognitive model, such as concept declarations, context declarations, spreading activation weights, and context/situation-cue-patterns.
Moodley, Kuven; Minati, Ludovico; Contarino, Valeria; Prioni, Sara; Wood, Ruth; Cooper, Rebecca; D'Incerti, Ludovico; Tagliavini, Fabrizio; Chan, Dennis
The hippocampus is one of the earliest brain regions affected in Alzheimer's disease (AD) and tests of hippocampal function have the potential to detect AD in its earliest stages. Given that the hippocampus is critically involved in allocentric spatial memory, this study applied a short test of spatial memory, the 4 Mountains Test (4MT), to determine whether test performance can differentiate mild cognitive impairment (MCI) patients with and without CSF biomarker evidence of underlying AD and whether the test can distinguish patients with MCI and mild AD dementia when applied in different cultural settings. Healthy controls (HC), patients with MCI, and mild AD dementia were recruited from study sites in UK and Italy. Study numbers were: HC (UK 20, Italy 10), MCI (UK 21, Italy 14), and AD (UK 11, Italy 9). Nineteen UK MCI patients were grouped into CSF biomarker-positive (MCI+, n = 10) and biomarker-negative (MCI-, n = 9) subgroups. Behavioral data were correlated with hippocampal volume and cortical thickness of the precuneus and posterior cingulate gyrus. Spatial memory was impaired in both UK and Italy MCI and AD patients. Test performance additionally differentiated between MCI+ and MCI- subgroups (P = 0.001). A 4MT score of ≤8/15 was associated with 100% sensitivity and 90% specificity for detection of early AD (MCI+ and mild AD dementia) in the UK population, and with 100% sensitivity and 50% specificity for detection of MCI and AD in the Italy sample. 4MT performance correlated with hippocampal volume in the UK population and cortical thickness of the precuneus in both study populations. In conclusion, performance on a hippocampus-sensitive test of spatial memory differentiates MCI due to AD with high diagnostic sensitivity and specificity. The observation that similar diagnostic sensitivity was obtained in two separate study populations, allied to the scalability and usability of the test in community memory clinics, supports future application of the 4MT
Broadbent, Hannah J; Farran, Emily K; Tolmie, Andy
Recent findings suggest that difficulties on small-scale visuospatial tasks documented in Williams syndrome (WS) also extend to large-scale space. In particular, individuals with WS often present with difficulties in allocentric spatial coding (encoding relationships between items within an environment or array). This study examined the effect of atypical spatial processing in WS on large-scale navigational strategies, using a novel 3D virtual environment. During navigation of recently learnt large-scale space, typically developing (TD) children predominantly rely on the use of a sequential egocentric strategy (recalling the sequence of left-right body turns throughout a route), but become more able to use an allocentric strategy between 5 and 10 years of age. The navigation strategies spontaneously employed by TD children between 5 and 10 years of age and individuals with WS were analysed. The ability to use an allocentric strategy on trials where spatial relational knowledge was required to find the shortest route was also examined. Results showed that, unlike TD children, during spontaneous navigation the WS group did not predominantly employ a sequential egocentric strategy. Instead, individuals with WS followed the path until the correct environmental landmarks were found, suggesting the use of a time-consuming and inefficient view-matching strategy for wayfinding. Individuals with WS also presented with deficits in allocentric spatial coding, demonstrated by difficulties in determining short-cuts when required and difficulties developing a mental representation of the environment layout. This was found even following extensive experience in an environment, suggesting that - unlike in typical development - experience cannot contribute to the development of spatial relational processing in WS. This atypical presentation of both egocentric and allocentric spatial encoding is discussed in relation to specific difficulties on small-scale spatial tasks and known
Bullens, Jessie; Igloi, Kinga; Berthoz, Alain; Postma, Albert; Rondi-Reig, Laure
Navigation in a complex environment can rely on the use of different spatial strategies. We have focused on the employment of "allocentric" (i.e., encoding interrelationships among environmental cues, movements, and the location of the goal) and "sequential egocentric" (i.e., sequences of body turns associated with specific choice points)…
Ramos, J M
In animal models of human amnesia, using lesion methods, it has been difficult to establish the role played by the hippocampus in the formation of long-term spatial knowledge. For example, lesions sustained after acquisition have generally produced a flat retrograde amnesia for spatial information. These results have not made it possible to dissociate the participation of the hippocampus in retrieval/performance processes from its participation in consolidation/retention. The present study was designed to investigate if electrolytic hippocampal lesions made before training lead to a deficit in the long-term retention of spatial knowledge when the rats show equal performance levels during the acquisition. Results show that lesioned rats learn a place response just as well as the control rats when, during the training, an intramaze cue orients the animal in its navigation towards the goal arm. One day after reaching criterion, lesioned and control rats remember the task perfectly during a transfer test in which the intramaze signal used previously is not present. However, 24 days later, the hippocampal animals manifest a profound deficit in the retention of the spatial information. When the spatial task learned during the acquisition phase requires only the use of a guidance strategy, control and lesioned animals show the same level of performance during the training phase and the same degree of retention during the retraining phase 24 days after criterion. Taken together, these results suggest that the hippocampus plays a crucial role in long-term retention of allocentric spatial information.
Fukumori, Kayoko; Okuda, Noboru; Yamaoka, Kosaku; Yanagisawa, Yasunobu
The ability to orient and navigate within a certain environment is essential for all animals, and spatial memory enables animals to remember the locations of such markers as predators, home, and food. Here we report that the migratory marine cardinalfish Apogon notatus has the potential to retain long-term spatial memory comparable to that of other animals. Female A. notatus establish a small territory on a shallow boulder bottom to pair and spawn with males. We carried out field research in two consecutive breeding seasons on territory settlement by individually marked females. Females maintained a territory at the same site throughout one breeding season. After overwintering in deep water, many of them (82.1%) returned to their breeding ground next spring and most occupied the same site as in the previous season, with only a 0.56 m shift on average. Our results suggest that female A. notatus have long-distance homing ability to pinpoint the exact location of their previous territory, and retain spatial memory for as long as 6 months.
Truchet, Bruno; Manrique, Christine; Sreng, Leam; Chaillan, Franck A; Roman, François S; Mourre, Christiane
Kv4 channels regulate the backpropagation of action potentials (b-AP) and have been implicated in the modulation of long-term potentiation (LTP). Here we showed that blockade of Kv4 channels by the scorpion toxin AmmTX3 impaired reference memory in a radial maze task. In vivo, AmmTX3 intracerebroventricular (i.c.v.) infusion increased and stabilized the EPSP-spike (E-S) component of LTP in the dentate gyrus (DG), with no effect on basal transmission or short-term plasticity. This increase in E-S potentiation duration could result from the combination of an increase in excitability of DG granular cells with a reduction of GABAergic inhibition, leading to a strong reduction of input specificity. Radioactive in situ hybridization (ISH) was used to evaluate the amounts of Kv4.2 and Kv4.3 mRNA in brain structures at different stages of a spatial learning task in naive, pseudoconditioned, and conditioned rats. Significant differences in Kv4.2 and Kv4.3 mRNA levels were observed between conditioned and pseudoconditioned rats. Kv4.2 and Kv4.3 mRNA levels were transiently up-regulated in the striatum, nucleus accumbens, retrosplenial, and cingulate cortices during early stages of learning, suggesting an involvement in the switch from egocentric to allocentric strategies. Spatial learning performance was positively correlated with the levels of Kv4.2 and Kv4.3 mRNAs in several of these brain structures. Altogether our findings suggest that Kv4 channels could increase the signal-to-noise ratio during information acquisition, thereby allowing a better encoding of the memory trace.
Walrave, Laura; Vinken, Mathieu; Albertini, Giulia; De Bundel, Dimitri; Leybaert, Luc; Smolders, Ilse J.
Astrocytes are active players in higher brain function as they can release gliotransmitters, which are essential for synaptic plasticity. Various mechanisms have been proposed for gliotransmission, including vesicular mechanisms as well as non-vesicular ones, for example by passive diffusion via connexin hemichannels (HCs). We here investigated whether interfering with connexin43 (Cx43) HCs influenced hippocampal spatial memory. We made use of the peptide Gap19 that blocks HCs but not gap junction channels and is specific for Cx43. To this end, we microinfused transactivator of transcription linked Gap19 (TAT-Gap19) into the brain ventricle of male NMRI mice and assessed spatial memory in a Y maze. We found that the in vivo blockade of Cx43 HCs did not affect the locomotor activity or spatial working memory in a spontaneous alternation Y maze task. Cx43 blockade did however significantly impair the spatial short-term memory in a delayed spontaneous alternation Y maze task. These results indicate that Cx43 HCs play a role in spatial short-term memory. PMID:28066184
Beaudet, Gregory; Jozet-Alves, Christelle; Asselot, Rachel; Schumann-Bard, Pascale; Freret, Thomas; Boulouard, Michel; Paizanis, Eleni
Spatial navigation is achieved through both egocentric (body-centered) and allocentric (externally-centered) strategies but decline with age, especially allocentric strategies. A better understanding of the neurobiological mechanisms underlying these strategies would allow the development of new treatments to mitigate this deterioration. Among them, the modulation of 5-HT7 receptor (5-HT7R) may constitute a potential strategy. Indeed, this receptor is known to play a role in spatial navigation, however its precise role in egocentric and allocentric strategies remains unclear. Here, we first examined the effect of 5-HT7 genetic invalidation (knock-out (KO) mice) in two versions of a water cross-maze task in which only egocentric or allocentric strategies were efficient to solve the task. Our results demonstrated that KO mice are able to learn an allocentric strategy. However, contrary to wild-type mice (WT mice), the acquisition rate was slower compared to the task requiring the acquisition of an egocentric strategy. Mice were then trained in a third version of the water maze, allowing the use of both egocentric and allocentric strategies. When facing conflicting spatial information, both KO and WT mice preferentially used an egocentric strategy. However, only WT mice displayed a greater latency to achieve the task. This suggests that WT mice are able to learn both information in parallel, but not KO mice (i.e. only learning an egocentric strategy). Altogether, these results provide evidence for the essential role of the 5HT7R in the acquisition of an allocentric strategy and in the ability to learn concomitantly both strategies.
Oosterman, Joukje M.; Morel, Sascha; Meijer, Lisette; Buvens, Cleo; Kessels, Roy P. C.; Postma, Albert
The present study was intended to compare age effects on visual and spatial working memory by using two versions of the same task that differed only in presentation mode. The working memory task contained both a simultaneous and a sequential presentation mode condition, reflecting, respectively, visual and spatial working memory processes. Young…
The etiology of anorexia nervosa (AN) is still unclear, despite that it is a critical and potentially mortal illness. A recent neurobiological model considers AN as the outcome of dysfunctions in the neuronal processes related to appetite and emotionality (Kaye et al., 2009, 2013). However, this model still is not able to answer a critical question: What is behind body image disturbances (BIDs) in AN? The article starts its analysis from reviewing some of the studies exploring the effects of the serotonin systems in memory (episodic, working, and spatial) and its dysfunctions. The review suggests that serotonin disturbances may: (a) facilitate the encoding of third person (allocentric) episodic memories; (b) facilitate the consolidation of emotional episodic memories (e.g., teasing), if preceded by repeated stress; (c) reduce voluntary inhibition of mnestic contents; (d) impair allocentric spatial memory. If we discuss these results within the interpretative frame suggested by the “Allocentric Lock Hypothesis” (Riva, 2012, 2014), we can hypothesize that altered serotoninergic activity in AN patients: (i) improves their ability to store and consolidate negative autobiographical memories, including those of their body, in allocentric perspective; (ii) impairs their ability to trigger voluntary inhibition of the previously stored negative memory of the body; (iii) impairs their capacity to retrieve/update allocentric information. Taken together, these points suggest a possible link between serotonin dysfunctions, memory impairments and BIDs: the impossibility of updating a disturbed body memory using real time experiential data—I'm locked to a wrong body stored in long term memory—pushes AN patients to control body weight and shape even when underweight. PMID:27932968
Wiholm, Clairy; Lowden, Arne; Kuster, Niels; Hillert, Lena; Arnetz, Bengt B; Akerstedt, Torbjörn; Moffat, Scott D
Radiofrequency (RF) emission during mobile phone use has been suggested to impair cognitive functions, that is, working memory. This study investigated the effects of a 2 1/2 h RF exposure (884 MHz) on spatial memory and learning, using a double-blind repeated measures design. The exposure was designed to mimic that experienced during a real-life mobile phone conversation. The design maximized the exposure to the left hemisphere. The average exposure was peak spatial specific absorption rate (psSAR10g) of 1.4 W/kg. The primary outcome measure was a "virtual" spatial navigation task modeled after the commonly used and validated Morris Water Maze. The distance traveled on each trial and the amount of improvement across trials (i.e., learning) were used as dependent variables. The participants were daily mobile phone users, with and without symptoms attributed to regular mobile phone use. Results revealed a main effect of RF exposure and a significant RF exposure by group effect on distance traveled during the trials. The symptomatic group improved their performance during RF exposure while there was no such effect in the non-symptomatic group. Until this new finding is further investigated, we can only speculate about the cause.
da Silva, Weber C N; Köhler, Cristiano C; Radiske, Andressa; Cammarota, Martín
We investigated the effect of the intra-CA1 administration of the D1/D5 receptor antagonist SCH23390 and the D1/D5 receptor agonist SKF38393 on spatial memory in the water maze. When given immediately, but not 3h after training, SCH23390 hindered long-term spatial memory formation without affecting non-spatial memory or the normal functionality of the hippocampus. On the contrary, post-training infusion of SKF38393 enhanced retention and facilitated the spontaneous recovery of the original spatial preference after reversal learning. Our findings demonstrate that hippocampal D1/D5 receptors play an essential role in spatial memory processing.
Oliveira-Santos, Luiz Gustavo R; Forester, James D; Piovezan, Ubiratan; Tomas, Walfrido M; Fernandez, Fernando A S
Memory is among the most important and neglected forces that shapes animal movement patterns. Research on the movement-memory interface is crucial to understand how animals use spatial learning to navigate across space because memory-based navigation is directly linked to animals' space use and home range behaviour; however, because memory cannot be measured directly, it is difficult to account for. Here, we incorporated spatial memory into step selection functions (SSF) to understand how resource selection and spatial memory affect space use of feral hogs (Sus scrofa). We used Biased Random Bridge kernel estimates linked to residence time as a surrogate for memory and tested four conceptually different dynamic maps of spatial memory. We applied this memory-based SSF to a data set of hog relocations to evaluate the importance of land cover type, time of day and spatial memory on the animals' space use. Our approach has shown how the incorporation of spatial memory into animal movement models can improve estimates of habitat selection. Memory-based SSF provided a feasible way to gain insight into how animals use spatial learning to guide their movement decisions. We found that while hogs selected forested areas and water bodies and avoided grasslands during the day (primarily at noon), they had a strong tendency to select previously visited areas, mainly those held in recent memory. Beyond actively updating their memory with recent experiences, hogs were able to discriminate among spatial memories encoded at different circadian phases of their activity. Even though hogs are thought to have long memory retention, they likely relied on recent experiences because the local food resources are quickly depleted and slowly renewed, yielding an uncertain spatial distribution of resources.
Won, Bo-Yeong; Jiang, Yuhong V.
Recent empirical and theoretical work has depicted a close relationship between visual attention and visual working memory. For example, rehearsal in spatial working memory depends on spatial attention, whereas adding a secondary spatial working memory task impairs attentional deployment in visual search. These findings have led to the proposal…
Dal Martello, Maria F.; DeBruine, Lisa M.; Maloney, Laurence T.
Typical judgments involving faces are disrupted by inversion, with the Thatcher illusion serving as a compelling example. In two experiments, we examined how inversion affects allocentric kin recognition—the ability to judge the degree of genetic relatedness of others. In the first experiment, participants judged whether pairs of photographs of children portrayed siblings or unrelated children. Half of the pairs were siblings, half were unrelated. In three experimental conditions, photographs were viewed in upright orientation, flipped around a horizontal axis, or rotated 180°. Neither rotation nor flipping had any detectable effect on allocentric kin recognition. In the second experiment, participants judged pairs of photographs of adult women. Half of the pairs were sisters, half were unrelated. We again found no significant effect of facial inversion. Unlike almost all other face judgments, judgments of kinship from facial appearance do not rely on perceptual cues disrupted by inversion, suggesting that they rely more on spatially localized cues rather than “holistic” cues. We conclude that kin recognition is not simply a byproduct of other face perception abilities. We discuss the implications for cue combination models of other facial judgments that are affected by inversion. PMID:26381836
Spellman, Timothy; Rigotti, Mattia; Ahmari, Susanne E; Fusi, Stefano; Gogos, Joseph A; Gordon, Joshua A
Spatial working memory, the caching of behaviourally relevant spatial cues on a timescale of seconds, is a fundamental constituent of cognition. Although the prefrontal cortex and hippocampus are known to contribute jointly to successful spatial working memory, the anatomical pathway and temporal window for the interaction of these structures critical to spatial working memory has not yet been established. Here we find that direct hippocampal-prefrontal afferents are critical for encoding, but not for maintenance or retrieval, of spatial cues in mice. These cues are represented by the activity of individual prefrontal units in a manner that is dependent on hippocampal input only during the cue-encoding phase of a spatial working memory task. Successful encoding of these cues appears to be mediated by gamma-frequency synchrony between the two structures. These findings indicate a critical role for the direct hippocampal-prefrontal afferent pathway in the continuous updating of task-related spatial information during spatial working memory.
Avraamides, Marios N.; Kelly, Jonathan W.
Recent models in spatial cognition posit that distinct memory systems are responsible for maintaining transient and enduring spatial relations. The authors used perspective-taking performance to assess the presence of these enduring and transient spatial memories for locations encoded through verbal descriptions. Across 3 experiments, spatial…
Uchimura, Motoaki; Kitazawa, Shigeru
Many previous studies have reported that our brains are able to encode a target position not only in body-centered coordinates but also in terms of landmarks in the background. The importance of such allocentric memory increases when we are forced to complete a delayed reaching task after the target has disappeared. However, the merit of allocentric memory in natural situations in which we are free to make an immediate reach toward a target has remained elusive. We hypothesized that allocentric memory is essential even in an immediate reach for dissociating between error attributable to the motor system and error attributable to target motion. We show here in humans that prism adaptation, that is, adaptation of reaching movements in response to errors attributable to displacement of the visual field, can be cancelled or enhanced simply by moving the background in mid-flight of the reaching movement. The results provide direct evidence for the novel contribution of allocentric memory in providing information on "where I intended to go," thereby discriminating the effect of target motion from the error resulting from the issued motor control signals.
Anooshian, L J; Wilson, K L
The present study examined developmental differences in the effect of route extensity on the memory for the locations of objects in a spatial array. Kindergarten and adult subjects were trained to remember the locations of 4 objects. During this training, objects were either connected by a combination of indirect, looped train tracks and direct train tracks (experimental subjects) or connected by entirely direct train-track routes (control subjects). Analyses of actual interobject distances, from subjects' reproductions of object locations on a response board (without train tracks), revealed that children, but not adults, distort distance in terms of the nature of travel observed between objects. Further testing revealed that differences in the amount of time taken for travel could not account for the results obtained with children.
Munneke, Jaap; Heslenfeld, Dirk J.; Theeuwes, Jan
The present study investigated how spatial working memory recruits early visual cortex. Participants were required to maintain a location in working memory while changes in blood oxygen level dependent (BOLD) signals were measured during the retention interval in which no visual stimulation was present. We show working memory effects during the…
Rinne, Teemu; Koistinen, Sonja; Talja, Suvi; Wikman, Patrik; Salonen, Oili
In the present study, we applied high-resolution functional magnetic resonance imaging (fMRI) of the human auditory cortex (AC) and adjacent areas to compare activations during spatial discrimination and spatial n-back memory tasks that were varied parametrically in difficulty. We found that activations in the anterior superior temporal gyrus (STG) were stronger during spatial discrimination than during spatial memory, while spatial memory was associated with stronger activations in the inferior parietal lobule (IPL). We also found that wide AC areas were strongly deactivated during the spatial memory tasks. The present AC activation patterns associated with spatial discrimination and spatial memory tasks were highly similar to those obtained in our previous study comparing AC activations during pitch discrimination and pitch memory (Rinne et al., 2009). Together our previous and present results indicate that discrimination and memory tasks activate anterior and posterior AC areas differently and that this anterior-posterior division is present both when these tasks are performed on spatially invariant (pitch discrimination vs. memory) or spatially varying (spatial discrimination vs. memory) sounds. These results also further strengthen the view that activations of human AC cannot be explained only by stimulus-level parameters (e.g., spatial vs. nonspatial stimuli) but that the activations observed with fMRI are strongly dependent on the characteristics of the behavioral task. Thus, our results suggest that in order to understand the functional structure of AC a more systematic investigation of task-related factors affecting AC activations is needed.
The analysis of spatial learning and memory in rodents is commonly used to investigate the mechanisms underlying certain forms of human cognition and to model their dysfunction in neuropsychiatric and neurodegenerative diseases. Proper interpretation of rodent behavior in terms of spatial memory and as a model of human cognitive functions is only possible if various navigation strategies and factors controlling the performance of the animal in a spatial task are taken into consideration. The aim of this review is to describe the experimental approaches that are being used for the study of spatial memory in rats and mice and the way that they can be interpreted in terms of general memory functions. After an introduction to the classification of memory into various categories and respective underlying neuroanatomical substrates, I explain the concept of spatial memory and its measurement in rats and mice by analysis of their navigation strategies. Subsequently, I describe the most common paradigms for spatial memory assessment with specific focus on methodological issues relevant for the correct interpretation of the results in terms of cognitive function. Finally, I present recent advances in the use of spatial memory tasks to investigate episodic-like memory in mice.
Beigneux, Katia; Plaie, Thierry; Isingrini, Michel
The aim of this study was to evaluate the effect of aging on the storage of visual and spatial working memory according to Logie's model of working memory (1995). In a first experiment young, elderly, and very old subjects carried out two tasks usually used to measure visual span (Visual Patterns Test) and spatial span (Corsi Block Tapping test).…
Motes, Michael A.; Hubbard, Timothy L.; Courtney, Jon R.; Rypma, Bart
Research has shown that spatial memory for moving targets is often biased in the direction of implied momentum and implied gravity, suggesting that representations of the subjective experiences of these physical principles contribute to such biases. The present study examined the association between these spatial memory biases. Observers viewed…
Rahman, Qazi; Bakare, Monsurat; Serinsu, Ceydan
Previous research has demonstrated a female advantage, albeit imperfectly, on tests of object location memory where object identity information is readily available. However, spatial and visual elements are often confounded in the experimental tasks used. Here spatial and visual memory performance was compared in 30 men and 30 women by presenting…
Rondina, Renante; Curtiss, Kaitlin; Meltzer, Jed A; Barense, Morgan D; Ryan, Jennifer D
Episodic memories are comprised of details of "where" and "when"; spatial and temporal relations, respectively. However, evidence from behavioural, neuropsychological, and neuroimaging studies has provided mixed interpretations about how memories for spatial and temporal relations are organised-they may be hierarchical, fully interactive, or independent. In the current study, we examined the interaction of memory for spatial and temporal relations. Using explicit reports and eye-tracking, we assessed younger and older adults' memory for spatial and temporal relations of objects that were presented singly across time in unique spatial locations. Explicit change detection of spatial relations was affected by a change in temporal relations, but explicit change detection of temporal relations was not affected by a change in spatial relations. Younger and older adults showed eye movement evidence of incidental memory for temporal relations, but only younger adults showed eye movement evidence of incidental memory for spatial relations. Together, these findings point towards a hierarchical organisation of relational memory. The implications of these findings are discussed in the context of the neural mechanisms that may support such a hierarchical organisation of memory.
in press). Beyond language comprehension: Situation models as a form of autobiographical memory . In F. Schmalhofer & C. Perfetti (Eds.) Higher level...Technical Report 1221 Comprehension and Memory of Spatial and Temporal Event Components Gabriel A. Radvansky University of Notre Dame January 2008...SUBTITLE 5a. CONTRACT OR GRANT NUMBER Comprehension and memory of spatial and temporal event DASW01-02-K-0003 components 5b. PROGRAM ELEMENT NUMBER
Rosati, Alexandra G; Hare, Brian
Spatial cognition and memory are critical cognitive skills underlying foraging behaviors for all primates. While the emergence of these skills has been the focus of much research on human children, little is known about ontogenetic patterns shaping spatial cognition in other species. Comparative developmental studies of nonhuman apes can illuminate which aspects of human spatial development are shared with other primates, versus which aspects are unique to our lineage. Here we present three studies examining spatial memory development in our closest living relatives, chimpanzees (Pan troglodytes) and bonobos (P. paniscus). We first compared memory in a naturalistic foraging task where apes had to recall the location of resources hidden in a large outdoor enclosure with a variety of landmarks (Studies 1 and 2). We then compared older apes using a matched memory choice paradigm (Study 3). We found that chimpanzees exhibited more accurate spatial memory than bonobos across contexts, supporting predictions from these species' different feeding ecologies. Furthermore, chimpanzees - but not bonobos - showed developmental improvements in spatial memory, indicating that bonobos exhibit cognitive paedomorphism (delays in developmental timing) in their spatial abilities relative to chimpanzees. Together, these results indicate that the development of spatial memory may differ even between closely related species. Moreover, changes in the spatial domain can emerge during nonhuman ape ontogeny, much like some changes seen in human children.
Gunzelmann, Glenn; Lyon, Don R
Spatial memory and reasoning rely heavily on allocentric (often map-like) representations of spatial knowledge. While research has documented many ways in which spatial information can be represented in allocentric form, less is known about how such representations are constructed. For example: Are the very early, pre-attentive parts of the process hard-wired, or can they be altered by experience? We addressed this issue by presenting sub-saccadic (53 ms) masked stimuli consisting of a target among one to three reference features. We then shifted the location of the feature array, and asked participants to identify the target's new relative location. Experience altered feature processing even when the display duration was too short to allow attention re-allocation. The results demonstrate the importance of early perceptual processes in the creation of representations of spatial location, and the malleability of those processes based on experience and expectations.
Rosati, Alexandra G; Rodriguez, Kerri; Hare, Brian
Evolutionary theories suggest that ecology is a major factor shaping cognition in primates. However, there have been few systematic tests of spatial memory abilities involving multiple primate species. Here, we examine spatial memory skills in four strepsirrhine primates that vary in level of frugivory: ruffed lemurs (Varecia sp.), ring-tailed lemurs (Lemur catta), mongoose lemurs (Eulemur mongoz), and Coquerel's sifakas (Propithecus coquereli). We compare these species across three studies targeting different aspects of spatial memory: recall after a long-delay, learning mechanisms supporting memory and recall of multiple locations in a complex environment. We find that ruffed lemurs, the most frugivorous species, consistently showed more robust spatial memory than the other species across tasks-especially in comparison with sifakas, the most folivorous species. We discuss these results in terms of the importance of considering both ecological and social factors as complementary explanations for the evolution of primate cognitive skills.
Nemes, V A; Whitaker, D; Heron, J; McKeefry, D J
Current models of short-term visual perceptual memory invoke mechanisms that are closely allied to low-level perceptual discrimination mechanisms. The purpose of this study was to investigate the extent to which human visual perceptual memory for spatial frequency is based upon multiple, spatially tuned channels similar to those found in the earliest stages of visual processing. To this end we measured how performance on a delayed spatial frequency discrimination paradigm was affected by the introduction of interfering or 'memory masking' stimuli of variable spatial frequency during the delay period. Masking stimuli were shown to induce shifts in the points of subjective equality (PSE) when their spatial frequencies were within a bandwidth of 1.2 octaves of the reference spatial frequency. When mask spatial frequencies differed by more than this value, there was no change in the PSE from baseline levels. This selective pattern of masking was observed for different spatial frequencies and demonstrates the existence of multiple, spatially tuned mechanisms in visual perceptual memory. Memory masking effects were also found to occur for horizontal separations of up to 6 deg between the masking and test stimuli and lacked any orientation selectivity. These findings add further support to the view that low-level sensory processing mechanisms form the basis for the retention of spatial frequency information in perceptual memory. However, the broad range of transfer of memory masking effects across spatial location and other dimensions indicates more long range, long duration interactions between spatial frequency channels that are likely to rely contributions from neural processes located in higher visual areas.
Weiss, Alison R; Bachevalier, Jocelyne
The contribution of the perirhinal cortex (PRh) to recognition memory is well characterized in adults, yet the same lesions have limited effect on recognition of spatial locations. Here, we assessed whether the same outcomes will follow when perirhinal lesions are performed in infancy. Monkeys with neonatal perirhinal (Neo-PRh) lesions and control animals were tested in three operant recognition tasks as they reached adulthood: Delayed Nonmatching-to-Sample (DNMS) and Object Memory Span (OMS), measuring object recognition, and Spatial Memory Span (SMS), measuring recognition of spatial locations. Although Neo-PRh lesions did not impact acquisition of the DNMS rule, they did impair performance when the delays were extended from 30s to 600s. In contrast, the same neonatal lesions had no impact on either the object or spatial memory span tasks, suggesting that the lesions impacted the maintenance of information across longer delays and not memory capacity. Finally, the magnitude of recognition memory impairment after the Neo-PRh lesions was similar to that previously observed after adult-onset perirhinal lesions, indicating minimal, or no, functional compensation after the early PRh lesions. Overall, the results indicate that the PRh is a cortical structure that is important for the normal development of mechanisms supporting object recognition memory. Its contribution may be relevant to the memory impairment observed with human cases of temporal lobe epilepsy without hippocampal sclerosis, but not to the memory impairment found in developmental amnesia cases. PMID:26593109
Postma, Albert; Jager, Gerry; Kessels, Roy P. C.; Koppeschaar, Hans P. F.; van Honk, Jack
In the present study, a systematic comparison of sex differences for several tests of spatial memory was conducted. Clear evidence for more accurate male performance was obtained for precise metric positional information in a wayfinding task and in an object location memory task. In contrast, no sex difference characterized topological information…
Crawford, L. Elizabeth; Landy, David; Salthouse, Timothy A.
Spatial memory research has attributed systematic bias in location estimates to a combination of a noisy memory trace with a prior structure that people impose on the space. Little is known about intraindividual stability and interindividual variation in these patterns of bias. In the current work, we align recent empirical and theoretical work on…
Mou, Weimin; Liu, Xianyun; McNamara, Timothy P.
Two experiments investigated whether the spatial reference directions that are used to specify objects' locations in memory can be solely determined by layout geometry. Participants studied a layout of objects from a single viewpoint while their eye movements were recorded. Subsequently, participants used memory to make judgments of relative…
Nelson, Charles A.; Monk, Christopher S.; Lin, Joseph; Carver, Leslie J.; Thomas, Kathleen M.; Truwit, Charles L.
Used functional magnetic resonance imaging (fMRI) to examine spatial working memory in 8- to 11-year-olds tested under 3 conditions. Found that subtracting activation of the motor condition from the memory condition revealed activity in dorsal aspects of the prefrontal cortex and in the posterior parietal and anterior cingulate cortex. Analysis of…
Robin, Jessica; Wynn, Jordana; Moscovitch, Morris
Events always unfold in a spatial context, leading to the claim that it serves as a scaffold for encoding and retrieving episodic memories. The ubiquitous co-occurrence of spatial context with events may induce participants to generate a spatial context when hearing scenarios of events in which it is absent. Spatial context should also serve as an…
Pearson, David G; Ball, Keira; Smith, Daniel T
There is little consensus regarding the specific processes responsible for encoding, maintenance, and retrieval of information in visuo-spatial working memory (VSWM). One influential theory is that VSWM may involve activation of the eye-movement (oculomotor) system. In this study we experimentally prevented healthy participants from planning or executing saccadic eye-movements during the encoding, maintenance, and retrieval stages of visual and spatial working memory tasks. Participants experienced a significant reduction in spatial memory span only when oculomotor preparation was prevented during encoding or maintenance. In contrast there was no reduction when oculomotor preparation was prevented only during retrieval. These results show that (a) involvement of the oculomotor system is necessary for optimal maintenance of directly-indicated locations in spatial working memory and (b) oculomotor preparation is not necessary during retrieval from spatial working memory. We propose that this study is the first to unambiguously demonstrate that the oculomotor system contributes to the maintenance of spatial locations in working memory independently from the involvement of covert attention.
Ariel, Robert; Moffat, Scott D
Spatial cognitive performance is impaired in later adulthood but it is unclear whether the metacognitive processes involved in monitoring spatial cognitive performance are also compromised. Inaccurate monitoring could affect whether people choose to engage in tasks that require spatial thinking and also the strategies they use in spatial domains such as navigation. The current experiment examined potential age differences in monitoring spatial cognitive performance in a variety of spatial domains including visual-spatial working memory, spatial orientation, spatial visualization, navigation, and place learning. Younger and older adults completed a 2D mental rotation test, 3D mental rotation test, paper folding test, spatial memory span test, two virtual navigation tasks, and a cognitive mapping test. Participants also made metacognitive judgments of performance (confidence judgments, judgments of learning, or navigation time estimates) on each trial for all spatial tasks. Preference for allocentric or egocentric navigation strategies was also measured. Overall, performance was poorer and confidence in performance was lower for older adults than younger adults. In most spatial domains, the absolute and relative accuracy of metacognitive judgments was equivalent for both age groups. However, age differences in monitoring accuracy (specifically relative accuracy) emerged in spatial tasks involving navigation. Confidence in navigating for a target location also mediated age differences in allocentric navigation strategy use. These findings suggest that with the possible exception of navigation monitoring, spatial cognition may be spared from age-related decline even though spatial cognition itself is impaired in older age.
Varner, Kaitlin M; Dopkins, Stephen; Philbeck, John W
The present research examined the effect of encoding from multiple viewpoints on scene recall in a group of younger (18-22 years) and older (65-80 years) adults. Participants completed a visual search task, during which they were given the opportunity to examine a room using two sets of windows that partitioned the room differently. Their choice of window set was recorded, to determine whether an association between these choices and spatial memory performance existed. Subsequently, participants were tested for spatial memory of the domain in which the search task was completed. Relative to younger adults, older adults demonstrated an increased tendency to use a single set of windows as well as decreased spatial memory for the domain. Window-set usage was associated with spatial memory, such that older adults who relied more heavily on a single set of windows also had better performance on the spatial memory task. These findings suggest that, in older adults, moderation in exploratory behavior may have a positive effect on memory for the domain of exploration.
Ramos, Juan M J
In previous studies we have suggested that the dorsal hippocampus is involved in spatial consolidation by showing that rats with electrolytic hippocampal lesions exhibit a profound deficit in the retention of an allocentric task 24 days after the acquisition. However, in various hippocampal-dependent tasks, several studies have shown an overestimation of the behavioral deficit when electrolytic versus axon-sparing cytotoxic lesions has been used. For this reason, in this report we compare the effects on spatial retention of electrolytic and neurotoxic lesions to the dorsal hippocampus. Results showed a similar deficit in spatial retention in both groups 24 days after acquisition. Thus, the hippocampus proper and not fibers of passage or extrahippocampal damage is directly responsible for the deficit in spatial retention seen in rats with electrolytic lesions.
Nagel, Bonnie J.; Herting, Megan M.; Maxwell, Emily C.; Bruno, Richard; Fair, Damien
Adult functional magnetic resonance imaging (fMRI) literature suggests that a left-right hemispheric dissociation may exist between verbal and spatial working memory (WM), respectively. However, investigation of this type has been obscured by incomparable verbal and spatial WM tasks and/or visual inspection at arbitrary thresholds as means to…
Rosati, Alexandra G.; Hare, Brian
Spatial cognition and memory are critical cognitive skills underlying foraging behaviors for all primates. While the emergence of these skills has been the focus of much research on human children, little is known about ontogenetic patterns shaping spatial cognition in other species. Comparative developmental studies of nonhuman apes can…
Olive, Thierry; Kellogg, Ronald T.; Piolat, Annie
Two experiments examined whether text composition engages verbal, visual, and spatial working memory to different degrees. In Experiment 1, undergraduate students composed by longhand a persuasive text while performing a verbal, visual, or spatial concurrent task that was presented visually. In Experiment 2, participants performed a verbal or…
Lee, Sang Ah; Tucci, Valter; Sovrano, Valeria Anna; Vallortigara, Giorgio
Researchers in spatial cognition have debated for decades the specificity of the mechanisms through which spatial information is processed and stored. Interestingly, although rodents are the preferred animal model for studying spatial navigation, the behavioral methods traditionally used to assess spatial memory do not effectively test the predictions of specificity in their representation. To address such issues, the present study tested the ability of mice to use boundary geometry and features to remember a goal location across 2 types of tasks--a working memory task with a changing goal location, and a reference memory task with 1 rewarded goal location. We show for the first time that mice, like other animals, can successfully encode boundary geometry in a working memory spatial mapping task, just as they do in a reference memory task. Their use of a nongeometric featural cue (striped pattern), in contrast, was more limited in the working memory task, although it quickly improved in the reference memory task. We discuss the implications of these findings for future research on the neural and genetic underpinnings of spatial representations.
Burnham, Veronica; Sundby, Christopher; Laman-Maharg, Abigail; Thornton, Janice
Luteinizing hormone (LH) rises dramatically during and after menopause, and has been correlated with an increased incidence of Alzheimer's disease and decreased memory performance in humans and animal models. To test whether LH acts directly on the dorsal hippocampus to affect memory, ovariectomized female rats were infused with either the LH-homologue human chorionic gonadotropin (hCG) or the LH receptor antagonist deglycosylated-hCG (dg-hCG). Infusion of hCG into either the lateral ventricle or the dorsal hippocampus caused significant memory impairments in ovariectomized estradiol-treated females. Consistent with this, infusion of the LH antagonist dg-hCG into the dorsal hippocampus caused an amelioration of memory deficits in ovariectomized females. Furthermore, the gonadotropin-releasing hormone antagonist Antide, failed to act in the hippocampus to affect memory. These findings demonstrate a significant role for LH action in the dorsal hippocampus in spatial memory dysfunction.
Irrazabal, Natalia; Burin, Debora
During the comprehension of narrative texts, readers keep a mental representation of the location of protagonists and objects; a breach in spatial coherence is detected by longer online reading times (consistency effect). We addressed whether these spatial inferences involve verbal or spatial working memory in two experiments, combining the consistency paradigm with selective verbal and spatial working memory concurrent tasks. The first experiment found longer reading times with a concurrent spatial task under imagery instructions (t33 = 2.87, p = .021). The second experiment, under comprehension reading instructions, found effects of verbal interference on reading times and accuracy. With a verbal secondary task, reading times for the target sentence were shorter (t45 = 3.60, p = .004) and the error rate was significantly higher (t47 = 2.95, p = .005) than without interference. This pattern of results suggests that spatial inferences in narrative comprehension rely mainly on verbal resources, and spatial working memory resources are recruited when imagery is required.
Patai, Eva Zita; Buckley, Alice; Nobre, Anna Christina
A popular model of visual perception states that coarse information (carried by low spatial frequencies) along the dorsal stream is rapidly transmitted to prefrontal and medial temporal areas, activating contextual information from memory, which can in turn constrain detailed input carried by high spatial frequencies arriving at a slower rate along the ventral visual stream, thus facilitating the processing of ambiguous visual stimuli. We were interested in testing whether this model contributes to memory-guided orienting of attention. In particular, we asked whether global, low-spatial frequency (LSF) inputs play a dominant role in triggering contextual memories in order to facilitate the processing of the upcoming target stimulus. We explored this question over four experiments. The first experiment replicated the LSF advantage reported in perceptual discrimination tasks by showing that participants were faster and more accurate at matching a low spatial frequency version of a scene, compared to a high spatial frequency version, to its original counterpart in a forced-choice task. The subsequent three experiments tested the relative contributions of low versus high spatial frequencies during memory-guided covert spatial attention orienting tasks. Replicating the effects of memory-guided attention, pre-exposure to scenes associated with specific spatial memories for target locations (memory cues) led to higher perceptual discrimination and faster response times to identify targets embedded in the scenes. However, either high or low spatial frequency cues were equally effective; LSF signals did not selectively or preferentially contribute to the memory-driven attention benefits to performance. Our results challenge a generalized model that LSFs activate contextual memories, which in turn bias attention and facilitate perception.
Lin, Chien-Heng; Chen, Chien-Min; Lou, Yu-Chiung
The abilities of both spatial orientation and spatial memory play very important roles in human navigation and spatial cognition. Since such abilities are difficult to strengthen through books or classroom instruction, there are no particular curricula or methods to assist in their development. Therefore, this study develops a spatial…
Nategh, Mohsen; Nikseresht, Sara; Khodagholi, Fariba; Motamedi, Fereshteh
Nucleus incertus (NI) is a pontine nucleus which releases mainly GABA and relaxin-3 in rats. Its suggested functions include response to stress, arousal, and modulation of hippocampal theta rhythm. Since the role of NI in learning and memory has not been well characterized, therefore the involvement of this nucleus in spatial learning and memory and the aftermath hippocampal levels of c-fos and pCREB were evaluated. NI was targeted by implanting cannula in male rats. For reference memory, NI was inactivated by lidocaine (0.4 μl, 4%) at three stages of acquisition, consolidation and retrieval in Morris water maze paradigm. For working memory, NI was inactivated in acquisition and retrieval phases. Injection of lidocaine prior to the first training session of reference memory significantly increased the distance moved, suggesting that inactivation of NI delays acquisition in this spatial task. Inactivation also interfered with the retrieval phase of spatial reference memory, as the time in target quadrant for lidocaine group was less, and the escape latency was higher compared to the control group. However, no difference was observed in the consolidation phase. In the working memory task, with inter-trial intervals of 75 min, the escape latency was higher when NI was inactivated in the retrieval phase. In addition, c-fos and pCREB/CREB levels decreased in NI-inhibited rats. This study suggests that nucleus incertus might participate in acquisition of spatial reference, and retrieval of both spatial reference and working memory. Further studies should investigate possible roles of NI in the hippocampal plasticity.
Won, Bo-Yeong; Jiang, Yuhong V
Recent empirical and theoretical work has depicted a close relationship between visual attention and visual working memory. For example, rehearsal in spatial working memory depends on spatial attention, whereas adding a secondary spatial working memory task impairs attentional deployment in visual search. These findings have led to the proposal that working memory is attention directed toward internal representations. Here, we show that the close relationship between these 2 constructs is limited to some but not all forms of spatial attention. In 5 experiments, participants held color arrays, dot locations, or a sequence of dots in working memory. During the memory retention interval, they performed a T-among-L visual search task. Crucially, the probable target location was cued either implicitly through location probability learning or explicitly with a central arrow or verbal instruction. Our results showed that whereas imposing a visual working memory load diminished the effectiveness of explicit cuing, it did not interfere with probability cuing. We conclude that spatial working memory shares similar mechanisms with explicit, goal-driven attention but is dissociated from implicitly learned attention.
Kirch, Robert D; Pinnell, Richard C; Hofmann, Ulrich G; Cassel, Jean-Christophe
Spatial cognition research in rodents typically employs the use of maze tasks, whose attributes vary from one maze to the next. These tasks vary by their behavioral flexibility and required memory duration, the number of goals and pathways, and also the overall task complexity. A confounding feature in many of these tasks is the lack of control over the strategy employed by the rodents to reach the goal, e.g., allocentric (declarative-like) or egocentric (procedural) based strategies. The double-H maze is a novel water-escape memory task that addresses this issue, by allowing the experimenter to direct the type of strategy learned during the training period. The double-H maze is a transparent device, which consists of a central alleyway with three arms protruding on both sides, along with an escape platform submerged at the extremity of one of these arms. Rats can be trained using an allocentric strategy by alternating the start position in the maze in an unpredictable manner (see protocol 1; §4.7), thus requiring them to learn the location of the platform based on the available allothetic cues. Alternatively, an egocentric learning strategy (protocol 2; §4.8) can be employed by releasing the rats from the same position during each trial, until they learn the procedural pattern required to reach the goal. This task has been proven to allow for the formation of stable memory traces. Memory can be probed following the training period in a misleading probe trial, in which the starting position for the rats alternates. Following an egocentric learning paradigm, rats typically resort to an allocentric-based strategy, but only when their initial view on the extra-maze cues differs markedly from their original position. This task is ideally suited to explore the effects of drugs/perturbations on allocentric/egocentric memory performance, as well as the interactions between these two memory systems.
Crawford, L Elizabeth; Landy, David; Salthouse, Timothy A
Spatial memory research has attributed systematic bias in location estimates to a combination of a noisy memory trace with a prior structure that people impose on the space. Little is known about intraindividual stability and interindividual variation in these patterns of bias. In the current work, we align recent empirical and theoretical work on working memory capacity limits and spatial memory bias to generate the prediction that those with lower working memory capacity will show greater bias in memory of the location of a single item. Reanalyzing data from a large study of cognitive aging, we find support for this prediction. Fitting separate models to individuals' data revealed a surprising variety of strategies. Some were consistent with Bayesian models of spatial category use, however roughly half of participants biased estimates outward in a way not predicted by current models and others seemed to combine these strategies. These analyses highlight the importance of studying individuals when developing general models of cognition. (PsycINFO Database Record
Oosterman, Joukje M; Morel, Sascha; Meijer, Lisette; Buvens, Cléo; Kessels, Roy P C; Postma, Albert
The present study was intended to compare age effects on visual and spatial working memory by using two versions of the same task that differed only in presentation mode. The working memory task contained both a simultaneous and a sequential presentation mode condition, reflecting, respectively, visual and spatial working memory processes. Young and older participants had to remember the locations of five equal objects under three different conditions: a baseline (immediate recall), a maintenance (including a delay of 5 seconds), and a manipulation (e.g., relocate all objects one column to the right) condition. Only older adults performed worse on the sequential compared to the simultaneous baseline condition and only this group revealed lower performance on the sequential delay compared to the simultaneous delay condition. However, in both groups the manipulation condition affected performance on the simultaneous and sequential presentation modes to the same extent. The findings of this study therefore partially support an age-related differentiation between visual and spatial working memory, with a stronger age effect on spatial than on visual working memory.
Vendetti, Michael; Castel, Alan D; Holyoak, Keith J
People typically remember objects to which they have frequently been exposed, suggesting that memory is a by-product of perception. However, prior research has shown that people have exceptionally poor memory for the features of some objects (e.g., coins) to which they have been exposed over the course of many years. Here, we examined how people remember the spatial layout of the buttons on a frequently used elevator panel, to determine whether physical interaction (rather than simple exposure) would ensure the incidental encoding of spatial information. Participants who worked in an eight-story office building displayed very poor recall for the elevator panel but above-chance performance on a recognition test. Performance was related to how often and how recently the person had used the elevator. In contrast to their poor memory for the spatial layout of the elevator buttons, most people readily recalled small distinctive graffiti on the elevator walls. In a more implicit test, the majority were able to locate their office floor and the eighth floor button when asked to point toward these buttons when in the actual elevator, with the button labels covered. However, identification was very poor for other floors (including the first floor), suggesting that even frequent interaction with information does not always lead to accurate spatial memory. These findings have implications for understanding the complex relationships among attention, expertise, and memory.
Mayer, Uwe; Watanabe, Shigeru; Bischof, Hans-Joachim
The aim of the present review is to show that spatial learning and memory is not a specialty of just a few avian species, and to describe the role of the avian hippocampus in spatial learning, memory and orientation. Based on our own research in zebra finches, we try to give an (not complete and probably biased) overview of this topic, and we also discuss the question of functional equivalence of hippocampus in birds and in mammals in that we question how far theories developed for mammalian hippocampus can also be applied to the avian hippocampal formation.
Bannerman, Rachel L; Temminck, Elisha V; Sahraie, Arash
There is evidence that emotional stimuli capture spatial attention and that visual memory is enhanced for emotional content. Here we examine the relationship between emotional content of stimuli and interactions with spatial memory. To assess spatial memory, a modified version of the Corsi Blocks Task (CBT), utilising emotional stimuli, was employed. In the CBT a series of spatial positions are highlighted and the participant has to repeat these in the order in which they were produced. Results showed that presenting more meaningful stimuli, such as emotional faces (e.g. angry or happy) at the spatial locations in the CBT did not enhance spatial memory span relative to the presentation of neutral stimuli (e.g. neutral faces) or non-image stimuli signified by a change in the luminance of the blocks. In addition, saccadic eye movements performed during retention disrupted spatial memory for all items. This occurred irrespective of whether the item to be remembered was a face, a luminance-defined stimulus or whether the face carried emotional significance. The results were not related to the visibility of the test stimuli as participants recognised the emotion displayed by the faces significantly above chance and rated emotional faces as being more arousing than neutral faces. Changes in the type of emotional stimulus (e.g. fearful faces, emotional schematic faces, spiders or flowers) or encoding (short vs. long) duration did not alter the pattern of results. These findings demonstrate an important dissociation between spatial capture and memory. Although emotional content can modulate orienting behaviour, it appears to be of limited effect on spatial memory.
Narimoto, Tadamasa; Matsuura, Naomi; Takezawa, Tomohiro; Mitsuhashi, Yoshinori; Hiratani, Michio
The authors investigated whether impaired spatial short-term memory exhibited by children with nonverbal learning disabilities is due to a problem in the encoding process. Children with or without nonverbal learning disabilities performed a simple spatial test that required them to remember 3, 5, or 7 spatial items presented simultaneously in random positions (i.e., spatial configuration) and to decide if a target item was changed or all items including the target were in the same position. The results showed that, even when the spatial positions in the encoding and probe phases were similar, the mean proportion correct of children with nonverbal learning disabilities was 0.58 while that of children without nonverbal learning disabilities was 0.84. The authors argue with the results that children with nonverbal learning disabilities have difficulty encoding relational information between spatial items, and that this difficulty is responsible for their impaired spatial short-term memory.
Kerbler, Georg M; Nedelska, Zuzana; Fripp, Jurgen; Laczó, Jan; Vyhnalek, Martin; Lisý, Jiří; Hamlin, Adam S; Rose, Stephen; Hort, Jakub; Coulson, Elizabeth J
The basal forebrain degenerates in Alzheimer's disease (AD) and this process is believed to contribute to the cognitive decline observed in AD patients. Impairment in spatial navigation is an early feature of the disease but whether basal forebrain dysfunction in AD is responsible for the impaired navigation skills of AD patients is not known. Our objective was to investigate the relationship between basal forebrain volume and performance in real space as well as computer-based navigation paradigms in an elderly cohort comprising cognitively normal controls, subjects with amnestic mild cognitive impairment and those with AD. We also tested whether basal forebrain volume could predict the participants' ability to perform allocentric- vs. egocentric-based navigation tasks. The basal forebrain volume was calculated from 1.5 T magnetic resonance imaging (MRI) scans, and navigation skills were assessed using the human analog of the Morris water maze employing allocentric, egocentric, and mixed allo/egocentric real space as well as computerized tests. When considering the entire sample, we found that basal forebrain volume correlated with spatial accuracy in allocentric (cued) and mixed allo/egocentric navigation tasks but not the egocentric (uncued) task, demonstrating an important role of the basal forebrain in mediating cue-based spatial navigation capacity. Regression analysis revealed that, although hippocampal volume reflected navigation performance across the entire sample, basal forebrain volume contributed to mixed allo/egocentric navigation performance in the AD group, whereas hippocampal volume did not. This suggests that atrophy of the basal forebrain contributes to aspects of navigation impairment in AD that are independent of hippocampal atrophy.
LaDage, Lara D.; Roth, Timothy C.; Fox, Rebecca A.; Pravosudov, Vladimir V.
The adult hippocampus in birds and mammals undergoes neurogenesis and the resulting new neurons appear to integrate structurally and functionally into the existing neural architecture. However, the factors underlying the regulation of new neuron production is still under scrutiny. In recent years, the concept that spatial memory affects adult hippocampal neurogenesis has gained acceptance, although results attempting to causally link memory use to neurogenesis remain inconclusive, possibly owing to confounds of motor activity, task difficulty or training for the task. Here, we show that ecologically relevant, spatial memory-based experiences of food caching and retrieving directly affect hippocampal neurogenesis in mountain chickadees (Poecile gambeli). We found that restricting memory experiences in captivity caused significantly lower rates of neurogenesis, as determined by doublecortin expression, compared with captive individuals provided with such experiences. However, neurogenesis rates in both groups of captive birds were still greatly lower than those in free-ranging conspecifics. These findings show that ecologically relevant spatial memory experiences can directly modulate neurogenesis, separate from other confounds that may also independently affect neurogenesis. PMID:19939840
Mohan, T; de Supinski, B R; McKee, S A; Mueller, F; Yoo, A; Schulz, M
The growing processor/memory performance gap causes the performance of many codes to be limited by memory accesses. If known to exist in an application, strided memory accesses forming streams can be targeted by optimizations such as prefetching, relocation, remapping, and vector loads. Undetected, they can be a significant source of memory stalls in loops. Existing stream-detection mechanisms either require special hardware, which may not gather statistics for subsequent analysis, or are limited to compile-time detection of array accesses in loops. Formally, little treatment has been accorded to the subject; the concept of locality fails to capture the existence of streams in a program's memory accesses. The contributions of this paper are as follows. First, we define spatial regularity as a means to discuss the presence and effects of streams. Second, we develop measures to quantify spatial regularity, and we design and implement an on-line, parallel algorithm to detect streams - and hence regularity - in running applications. Third, we use examples from real codes and common benchmarks to illustrate how derived stream statistics can be used to guide the application of profile-driven optimizations. Overall, we demonstrate the benefits of our novel regularity metric as a low-cost instrument to detect potential for code optimizations affecting memory performance.
Shah, Darshna S; Prados, Jose; Gamble, Jasmin; De Lillo, Carlo; Gibson, Claire L
The present study assessed the spatial abilities of male and female human participants using different versions of the non-navigational Corsi block-tapping test (CBT) and a search task. Males performed significantly better than females on the standard manual version of the CBT; however, the standard CBT does not allow discrimination between spatial memory span and the role of spatial organisational factors (structure, path length and presence of crossings) in the sequences to recall. These organisational factors were assessed, therefore, in an experiment in which 7-block-sequences had to be recalled in a computerised version of the CBT. No sex differences in performance were observed on the computerised CBT, indicating that males do not make better use of spatial organisational principles. Accordingly, sex differences observed in the manual CBT are likely to rely upon differences in memory span between males and females. In the search task, participants could locate a goal by reference to a Euclidian space (the geometry of a virtual enclose) or to proximal non-geometric cues. Both male and female participants showed a preference for the non-geometric cues, which overshadowed learning about the geometric cues when the two sets were available simultaneously during the training stage. These results indicate that sex differences do exist in those tests which are dependent on memory span. Sex differences were absent, however, in spatial organisational skills or in the usage of Euclidian and egocentric strategies to solve problems relying on spatial ability.
Lanfranchi, Silvia; De Mori, Letizia; Mammarella, Irene C.; Carretti, Barbara; Vianello, Renzo
The aim of the present study was to compare visuospatial working memory performance in 18 individuals with Williams syndrome (WS) and 18 typically developing (TD) children matched for nonverbal mental age. Two aspects were considered: task presentation format (i.e., spatial-sequential or spatial-simultaneous), and level of attentional control…
Abrahamse, Elger; van Dijck, Jean-Philippe; Fias, Wim
Number-space associations are a robust observation, but their underlying mechanisms remain debated. Two major accounts have been identified. First, spatial codes may constitute an intrinsic part of number representations stored in the brain – a perspective most commonly referred to as the Mental Number Line account. Second, spatial codes may be generated at the level of working memory when number (or other) representations are coordinated in function of a specific task. The aim of the current paper is twofold. First, whereas a pure Mental Number Line account cannot capture the complexity of observations reported in the literature, we here explore if and how a pure working memory account can suffice. Second, we make explicit (more than in our earlier work) the potential building blocks of such a working memory account, thereby providing clear and concrete foci for empirical efforts to test the feasibility of the account. PMID:27445937
Tsujii, Takeo; Yamamoto, Eriko; Masuda, Sayako; Watanabe, Shigeru
This study longitudinally compared activity in the frontal cortex during a spatial working memory task between 5-year-old and 7-year-old children using near-infrared spectroscopy. Eight children participated in this study twice, once at 5 years and once at 7 years of age. Behavioral analysis showed that older children performed the working memory task more precisely and more rapidly than younger children. Near-infrared spectroscopy analysis showed that right hemisphere dominance was observed in older children, whereas no hemispheric difference was apparent in younger children. Children with strengthened lateralization showed improved performance from 5 to 7 years. We therefore offer the first demonstration of the developmental changes in frontal cortical activation during spatial working memory tasks during the preschool period.
Holden, Mark P.; Newcombe, Nora S.; Shipley, Thomas F.
Memories for spatial locations often show systematic errors toward the central value of the surrounding region. The Category Adjustment (CA) model suggests that this bias is due to a Bayesian combination of categorical and metric information, which offers an optimal solution under conditions of uncertainty (Huttenlocher, Hedges, & Duncan,…
Rossato, Janine I.; Medina, Jorge H.; Izquierdo, Ivan; Cammarota, Martin; Bevilaqua, Lia R. M.
Nonreinforced retrieval can cause extinction and/or reconsolidation, two processes that affect subsequent retrieval in opposite ways. Using the Morris water maze task we show that, in the rat, repeated nonreinforced expression of spatial memory causes extinction, which is unaffected by inhibition of protein synthesis within the CA1 region of the…
Anguera, Joaquin A.; Reuter-Lorenz, Patricia A.; Willingham, Daniel T.; Seidler, Rachael D.
Previous studies of motor learning have described the importance of cognitive processes during the early stages of learning; however, the precise nature of these processes and their neural correlates remains unclear. The present study investigated whether spatial working memory (SWM) contributes to visuomotor adaptation depending on the stage of…
Lavenex, Pierre; Lavenex, Pamela Banta
This experiment assesses spatial and nonspatial relational memory in freely moving 9-mo-old and adult (11-13-yr-old) macaque monkeys ("Macaca mulatta"). We tested the use of proximal landmarks, two different objects placed at the center of an open-field arena, as conditional cues allowing monkeys to predict the location of food rewards hidden in…
Thomas, Laura E.
Directed actions can play a causal role in cognition, shaping thought processes. What drives this cross-talk between action and thought? I investigated the hypothesis that representations in spatial working memory mediate interactions between directed actions and problem solving. Participants attempted to solve an insight problem while…
Galati, Alexia; Michael, Christina; Mello, Catherine; Greenauer, Nathan M.; Avraamides, Marios N.
We examined whether people spontaneously represent the partner's viewpoint in spatial memory when it is available in advance and whether they adapt their spontaneous descriptions accordingly. In 18 pairs, Directors studied arrays of objects while: (1) not knowing about having to describe the array to a Matcher, (2) knowing about the subsequent…
Méndez-Couz, M; Conejo, N M; Vallejo, G; Arias, J L
While the neuronal basis of spatial memory consolidation has been thoroughly studied, the substrates mediating the process of extinction remain largely unknown. This study aimed to evaluate the functional contribution of selected brain regions during the extinction of a previously acquired spatial memory task in the Morris water maze. For that purpose, we used adult male Wistar rats trained in a spatial reference memory task. Learning-related changes in c-Fos inmunoreactive cells after training were evaluated in cortical and subcortical regions. Results show that removal of the hidden platform in the water maze induced extinction of the previously reinforced escape behavior after 16 trials, without spontaneous recovery 24h later. Extinction was related with significantly higher numbers of c-Fos positive nuclei in amygdala nuclei and prefrontal cortex. On the other hand, the lateral mammillary bodies showed higher number of c-Fos positive cells than the control group. Therefore, in contrast with the results obtained in studies of classical conditioning, we show the involvement of diencephalic structures mediating this kind of learning. In summary, our findings suggest that medial prefrontal cortex, the amygdala complex and diencephalic structures like the lateral mammillary nuclei are relevant for the extinction of spatial memory.
Burns, Patrick; Russell, Charlotte; Russell, James
In two experiments, both employing deferred imitation, we studied the developmental origins of episodic memory in two- to three-year-old children by adopting a "minimalist" view of episodic memory based on its What-When-Where ("WWW": spatiotemporal plus semantic) content. We argued that the temporal element within spatiotemporal should be the order/simultaneity of the event elements, but that it is not clear whether the spatial content should be egocentric or allocentric. We also argued that episodic recollection should be configural (tending towards all-or-nothing recall of the WWW elements). Our first deferred imitation experiment, using a two-dimensional (2D) display, produced superior-to-chance performance after 2.5 years but no evidence of configural memory. Moreover, performance did not differ from that on a What-What-What control task. Our second deferred imitation study required the children to reproduce actions on an object in a room, thereby affording layout-based spatial cues. In this case, not only was there superior-to-chance performance after 2.5 years but memory was also configural at both ages. We discuss the importance of allocentric spatial cues in episodic recall in early proto-episodic memory and reflect on the possible role of hippocampal development in this process.
Rossato, Janine I.; Bevilaqua, Lia R.M.; Medina, Jorge H.; Izquierdo, Iván; Cammarota, Martín
Nonreinforced retrieval can cause extinction and/or reconsolidation, two processes that affect subsequent retrieval in opposite ways. Using the Morris water maze task we show that, in the rat, repeated nonreinforced expression of spatial memory causes extinction, which is unaffected by inhibition of protein synthesis within the CA1 region of the dorsal hippocampus. However, if the number of nonreinforced retrieval trials is insufficient to induce long-lasting extinction, then a hippocampal protein synthesis-dependent reconsolidation process recovers the original memory. Inhibition of hippocampal protein synthesis after reversal learning sessions impairs retention of the reversed preference and blocks persistence of the original one, suggesting that reversal learning involves reconsolidation rather than extinction of the original memory. Our results suggest the existence of a hippocampal protein synthesis-dependent reconsolidation process that operates to recover or update retrieval-weakened memories from incomplete extinction. PMID:16882860
Serino, Silvia; Morganti, Francesca; Di Stefano, Fabio; Riva, Giuseppe
Several studies have pointed out that egocentric and allocentric spatial impairments are one of the earliest manifestations of Alzheimer’s Disease (AD). It is less clear how a break in the continuous interaction between these two representations may be a crucial marker to detect patients who are at risk to develop dementia. The main objective of this study is to compare the performances of participants suffering from amnestic mild cognitive impairment (aMCI group), patients with AD (AD group) and a control group (CG), using a virtual reality (VR)-based procedure for assessing the abilities in encoding, storing and syncing different spatial representations. In the first task, participants were required to indicate on a real map the position of the object they had memorized, while in the second task they were invited to retrieve its position from an empty version of the same virtual room, starting from a different position. The entire procedure was repeated across three different trials, depending on the object location in the encoding phase. Our finding showed that aMCI patients performed significantly more poorly in the third trial of the first task, showing a deficit in the ability to encode and store an allocentric viewpoint independent representation. On the other hand, AD patients performed significantly more poorly when compared to the CG in the second task, indicating a specific impairment in storing an allocentric viewpoint independent representation and then syncing it with the allocentric viewpoint dependent representation. Furthermore, data suggested that these impairments are not a product of generalized cognitive decline or of general decay in spatial abilities, but instead may reflect a selective deficit in the spatial organization Overall, these findings provide an initial insight into the cognitive underpinnings of amnestic impairment in aMCI and AD patient exploiting the potentiality of VR. PMID:26042034
Hsu, Wei-Lun; Ma, Yun-Li; Hsieh, Ding-You; Liu, Yen-Chen; Lee, Eminy Hy
Signal transducer and activator of transcription-1 (STAT1) has an important role in inflammation and the innate immune response, but its role in the central nervous system is less well understood. Here, we examined the role of STAT1 in spatial learning and memory, and assessed the involvement of STAT1 in mediating the memory-impairing effect of amyloid-beta (Aβ). We found that water maze training downregulated STAT1 expression in the rat hippocampal CA1 area, and spatial learning and memory function was enhanced in Stat1-knockout mice. Conversely, overexpression of STAT1 impaired water maze performance. STAT1 strongly upregulated the expression of the extracellular matrix protein laminin β1 (LB1), which also impaired water maze performance in rats. Furthermore, Aβ impaired spatial learning and memory in association with a dose-dependent increase in STAT1 and LB1 expression, but knockdown of STAT1 and LB1 both reversed this effect of Aβ. This Aβ-induced increase in STAT1 and LB1 expression was also associated with a decrease in the expression of the N-methyl-D-aspartate receptor (NMDAR) subunits, NR1, and NR2B. Overexpression of NR1 or NR2B or exogenous application of NMDA reversed Aβ-induced learning and memory deficits as well as Aβ-induced STAT1 and LB1 expression. Our results demonstrate that STAT1 negatively regulates spatial learning and memory through transcriptional regulation of LB1 expression. We also identified a novel mechanism for Aβ pathogenesis through STAT1 induction. Notably, impairment of spatial learning and memory by this STAT1-mediated mechanism is independent of cAMP responsive element-binding protein signaling.
Riotte-Lambert, Louise; Benhamou, Simon; Chamaillé-Jammes, Simon
Home ranges (HRs) are a remarkably common form of animal space use, but we still lack an integrated view of the individual-level processes that can lead to their emergence and maintenance, particularly when individuals are in competition for resources. We built a spatially explicit mechanistic movement model to investigate how simple memory-based foraging rules may enable animals to establish HRs and to what extent this increases their foraging efficiency compared to individuals that do not base foraging decisions on memory. We showed that these simple rules enable individuals to perform better than individuals using the most efficient strategy that does not rely on memory and drive them to spatially segregate through avoidance of resource patches used by others. This striking result questions the common assumption that low HR overlaps are indicators of territorial behavior. Indeed, it appears that, by using an information-updating system, individuals can keep their environment relatively predictable without paying the cost of defending an exclusive space. However, memory-based foraging strategies leading to HR emergence seem unable to prevent the disruptive effects of the arrival of new individuals. This calls for further research on the mechanisms that can stabilize HR spatial organization in the long term.
Carlei, Christophe; Kerzel, Dirk
Hemispheric asymmetries were investigated by changing the horizontal position of stimuli that had to be remembered in a visuo-spatial short-term memory task. Observers looked at matrices containing a variable number of filled squares on the left or right side of the screen center. At stimulus offset, participants reproduced the positions of the filled squares in an empty response matrix. Stimulus and response matrices were presented in the same quadrant. We observed that memory performance was better when the matrices were shown on the left side of the screen. We distinguished between recall strategies that relied on visual or non-visual (verbal) cues and found that the effect of gaze position occurred more reliably in participants using visual recall strategies. Overall, the results show that there is a solid enhancement of visuo-spatial short-term memory when observers look to the left. In contrast, vertical position had no influence on performance. We suggest that unilateral gaze to the left activates centers in the right hemisphere contributing to visuo-spatial memory.
Loureiro, Michael; Lecourtier, Lucas; Engeln, Michel; Lopez, Joëlle; Cosquer, Brigitte; Geiger, Karin; Kelche, Christian; Cassel, Jean-Christophe; Pereira de Vasconcelos, Anne
Current views posit the dorsal hippocampus (DHipp) as contributing to spatial memory processes. Conversely, the ventral hippocampus (VHipp) modulates stress, emotions and affects. Arguments supporting this segregation include differences in (i) connectivity: the DHipp is connected with the entorhinal cortex which receives visuospatial neocortical inputs; the VHipp is connected with both the amygdala and hypothalamus, (ii) electrophysiological characteristics: there is a larger proportion of place cells in the DHipp than in the VHipp, and an increasing dorsoventral gradient in the size of place fields, suggesting less refined spatial coding in the VHipp, and (iii) consequences of lesions: spatial memory is altered after DHipp lesions, less dramatically, sometimes not, after VHipp lesions. Using reversible inactivation, we report in rats, that lidocaine infusions into the DHipp or VHipp right before a probe trial impair retrieval performance in a water-maze task. This impairment was found at two post-acquisition delays compatible with recent memory (1 and 5 days). Pre-training blockade of the VHipp did not prevent task acquisition and drug-free retrieval, on the contrary to pre-training blockade of DHipp, which altered performance in a subsequent drug-free probe trial. Complementary experiments excluded possible locomotor, sensorimotor, motivational or anxiety-related biases from data interpretation. Our conclusion is that a spatial memory can be acquired with the DHipp, less efficiently with the VHipp, and that the retrieval of such a memory and/or the expression of its representation engages the dorsoventral axis of the hippocampus when the task has been learnt with an entirely functional hippocampus.
Kobilo, Tali; Yuan, Chunyan; van Praag, Henriette
Physical activity improves learning and hippocampal neurogenesis. It is unknown whether compounds that increase endurance in muscle also enhance cognition. We investigated the effects of endurance factors, peroxisome proliferator-activated receptor δ agonist GW501516 and AICAR, activator of AMP-activated protein kinase on memory and neurogenesis. Mice were injected with GW for 7 d or AICAR for 7 or 14 d. Two weeks thereafter mice were tested in the Morris water maze. AICAR (7 d) and GW improved spatial memory. Moreover, AICAR significantly, and GW modestly, elevated dentate gyrus neurogenesis. Thus, pharmacological activation of skeletal muscle may mediate cognitive effects. PMID:21245211
Laczó, Jan; Andel, Ross; Nedelska, Zuzana; Vyhnalek, Martin; Vlcek, Kamil; Crutch, Sebastian; Harrison, John; Hort, Jakub
Spatial navigation (SN) impairment is present early in Alzheimer's disease (AD). We tested whether SN performance, self-centered (egocentric) and world-centered (allocentric), was distinguishable from performance on established cognitive functions-verbal and nonverbal memory, executive and visuospatial function, attention/working memory, and language function. 108 older adults (53 cognitively normal [CN] and 55 with amnestic mild cognitive impairment [aMCI]) underwent neuropsychological examination and real-space navigation testing. Subset (n = 63) had automated hippocampal volumetry. In a factor analysis, allocentric and egocentric navigation tasks loaded highly onto the same factor with low loadings on other factors comprising other cognitive functions. In linear regression, performance on other cognitive functions was not, or was only marginally, associated with spatial navigation performance in CN or aMCI groups. After adjustment for age, gender, and education, right hippocampal volume explained 26% of the variance in allocentric navigation in aMCI group. In conclusion, spatial navigation, a known cognitive marker of early AD, may be distinguished from other cognitive functions. Therefore, its assessment along with other major cognitive functions may be highly beneficial in terms of obtaining a comprehensive neuropsychological profile.
Smith, Alexandra E; Slivicki, Richard A; Hohmann, Andrea G; Crystal, Jonathon D
Chemotherapeutic agents are widely used to treat patients with systemic cancer. The efficacy of these therapies is undermined by their adverse side-effect profiles such as cognitive deficits that have a negative impact on the quality of life of cancer survivors. Cognitive side effects occur across a variety of domains, including memory, executive function, and processing speed. Such impairments are exacerbated under cognitive challenges and a subgroup of patients experience long-term impairments. Episodic memory in rats can be examined using a source memory task. In the current study, rats received paclitaxel, a taxane-derived chemotherapeutic agent, and learning and memory functioning was examined using the source memory task. Treatment with paclitaxel did not impair spatial and episodic memory, and paclitaxel treated rats were not more susceptible to cognitive challenges. Under conditions in which memory was not impaired, paclitaxel treatment impaired learning of new rules, documenting a decreased sensitivity to changes in experimental contingencies. These findings provide new information on the nature of cancer chemotherapy-induced cognitive impairments, particularly regarding the incongruent vulnerability of episodic memory and new learning following treatment with paclitaxel.
Toepper, M; Gebhardt, H; Beblo, T; Thomas, C; Driessen, M; Bischoff, M; Blecker, C R; Vaitl, D; Sammer, G
Executive working memory operations are related to prefrontal regions in the healthy brain. Moreover, neuroimaging data provide evidence for a functional dissociation of ventrolateral and dorsolateral prefrontal cortex. Most authors either suggest a modality-specific or a function-specific prefrontal cortex organization. In the present study we particularly aimed at the identification of different prefrontal cerebral areas that are involved in executive inhibitory processes during spatial working memory encoding. In an fMRI study (functional magnetic resonance imaging) we examined the neural correlates of spatial working memory processing by varying the amount of executive demands of the task. Twenty healthy volunteers performed the Corsi Block-Tapping test (CBT) during fMRI. The CBT requires the storage and reproduction of spatial target sequences. In a second condition, we presented an adapted version of the Block-Suppression-Test (BST). The BST is based on the original CBT but additionally requires the active suppression of visual distraction within the target sequences. In comparison to the CBT performance, particularly the left dorsolateral prefrontal cortex (BA 9) showed more activity during the BST condition. Our results show that the left dorsolateral prefrontal cortex plays a crucial role for executive controlled inhibition of spatial distraction. Furthermore, our findings are in line with the processing model of a functional dorsolateral-ventrolateral prefrontal cortex organization.
Golbeck, Susan L.
Children's memory for spatial locations in a room designed to look like a grocery store was examined. In the first of two studies, 48 preschoolers completed a memory task for spatial locations problem and an incidental recall task in two room arrangements varying in logical organization. Memory for spatial locations was higher in a clustered and…
Plescia, Fulvio; Marino, Rosa A M; Navarra, Michele; Gambino, Giuditta; Brancato, Anna; Sardo, Pierangelo; Cannizzaro, Carla
This study aims at providing an insight into early handling procedures on learning and memory performance in adult female rats. Early handling procedures were started on post-natal day 2 until 21, and consisted in 15 min, daily separations of the dams from their litters. Assessment of declarative memory was carried out in the novel-object recognition task; spatial learning, reference- and working memory were evaluated in the Morris water maze (MWM). Our results indicate that early handling induced an enhancement in: (1) declarative memory, in the object recognition task, both at 1h and 24h intervals; (2) reference memory in the probe test and working memory and behavioral flexibility in the "single-trial and four-trial place learning paradigm" of the MWM. Short-term separation by increasing maternal care causes a dampening in HPA axis response in the pups. A modulated activation of the stress response may help to protect brain structures, involved in cognitive function. In conclusion, this study shows the long-term effects of a brief maternal separation in enhancing object recognition-, spatial reference- and working memory in female rats, remarking the impact of early environmental experiences and the consequent maternal care on the behavioral adaptive mechanisms in adulthood.
Alaei, Hojjatallah; Moloudi, Rohallah; Sarkaki, Ali Reza; Azizi-Malekabadi, Hamid; Hanninen, Osmo
Previous studies have shown that physical activity improves learning and memory. Present study was performed to determine the effects of acute, chronic and continuous exercise with different periods on spatial learning and memory recorded as the latency and length of swim path in the Morris water maze testing in subsequent 8 days. Four rat groups were included as follows: 1- Group C (controls which did not exercise). 2- Group A (30 days treadmill running before and 8 days during the Morris water maze testing period). 3- Group B (30 days exercise before the Morris water maze testing period only) and 4- Group D (8 days exercise only during the Morris water maze testing period). The results showed that chronic (30 days) and continuous (during 8 days of Morris water maze testing days) treadmill training produced a significant enhancement in spatial learning and memory which was indicated by decreases in path length and latency to reach the platform in the Morris water maze test (p < 0.05). The benefits in these tests were lost in three days, if the daily running session was abandoned. In group D with acute treadmill running (8 days exercise only) the difference between the Group A disappeared in one week and benefit seemed to be obtained in comparison with the controls without running program. In conclusion the chronic and daily running exercises promoted learning and memory in Morris water maze, but the benefits were lost in few days without daily running sessions in adult rats. Key pointsDaily running influence on spatial memory.The velocity of learning can be influenced by running activity.Path length is important parameter for measuring the speed of learning.
Schutte, Anne R.; Spencer, John P.
This study tested a dynamic field theory (DFT) of spatial working memory and an associated spatial precision hypothesis (SPH). Between 3 and 6 years of age, there is a qualitative shift in how children use reference axes to remember locations: 3-year-olds' spatial recall responses are biased toward reference axes after short memory delays, whereas…
Christoffersen, Gert R J; Simonyi, Agnes; Schachtman, Todd R; Clausen, Bettina; Clement, David; Bjerre, Vicky K; Mark, Louise T; Reinholdt, Mette; Schmith-Rasmussen, Kati; Zink, Lena V B
Metabotropic glutamate receptor subtype 5 (mGlu5) has been implicated in memory processing in some but not all learning tasks. The reason why this receptor is involved in some tasks but not in others remains to be determined. The present experiments using rats examined effects of the mGlu5-antagonist 2-methyl-6-(phenylethynyl)-pyridine (MPEP)--applied systemically i.p. (1-10mg/kg) or bilaterally into the prelimbic cortex (1-10 microg)---on the ability of rats to explore and remember new stimuli. A cross-maze, open field, and object recognition task were used to evaluate exploration and memory and it was found that: (1) locomotion during exploration of spatial environments and exploration time at novel objects were reduced by i.p. but not by prelimbic administration of MPEP, (2) spatial short-term memory was impaired in cross-maze and object discrimination was reduced after both types of administration, (3) long-term retention of spatial conditioning in the cross-maze was inhibited after i.p. applications which (4) also inhibited spontaneous alternation performance during maze-exploration. Reduced exploratory locomotion and exploration time after i.p. injections may have contributed to the observed retention impairments. However, the fact that prelimbic administration of MPEP inhibited retention without reducing exploration shows that memory formation was also impacted directly by prelimbic mGlu5 in both spatial and non-spatial learning.
Tyurenkov, I N; Volotova, E V; Kurkin, D V
This work was aimed at evaluating the influence of gliatilin administration on the spatial memory in aged rats. Cognitive function and spatial memory in animals was evaluated using radial (8-beam) maze test. Errors of working spatial memory and reference memory were used as indicators of impaired cognitive function. It was found that aged (24-month) rats compared with younger (6-months) age group exhibited cognitive impairment, as manifested by deterioration of short- and long-term memory processes. Course administration of gliatilin in rats of the older age group at a dose of 100 mg/kg resulted in significant improvement of the working and reference spatial memory in aged rats.
Using Peripheral Processing and Spatial Memory to Facilitate Task Resumption Raj M. Ratwani1,2, Alyssa E. Andrews2, Malcolm McCurry1, J. Gregory...Trafton1,2, Matthew S. Peterson2 Naval Research Laboratory1 George Mason University2 Washington, D.C . Fairfax, VA...Participants. Thirty-three George Mason University undergraduate students participated for course credit. Materials. Thirty Microsoft Excel
Lavenex, Pierre; Lavenex, Pamela Banta
This experiment assesses spatial and nonspatial relational memory in freely moving 9-mo-old and adult (11-13-yr-old) macaque monkeys (Macaca mulatta). We tested the use of proximal landmarks, two different objects placed at the center of an open-field arena, as conditional cues allowing monkeys to predict the location of food rewards hidden in one of two sets of three distinct locations. Monkeys were tested in two different conditions: (1) when local visual cues marked the two sets of potentially baited locations, so that monkeys could use both local and spatial information to discriminate these locations from never-baited locations; and (2) when no local visual cues marked the two sets of potentially baited locations, so that monkeys had to rely on a spatial relational representation of the environment to discriminate these locations. No 9-mo-old or adult monkey associated the presence of the proximal landmarks, at the center of the arena, with the presence of food in one set of three distinct locations. All monkeys, however, discriminated the potentially baited locations in the presence of local visual cues, thus providing evidence of visual discrimination learning. More importantly, all 9-mo-old monkeys tested discriminated the potentially baited locations in absence of the local visual cues, thus exhibiting evidence of spatial relational learning. These findings indicate that spatial memory processes characterized by a relational representation of the environment are present as early as 9 mo of age in macaque monkeys.
Beatty, W W; Rush, J R
To assess the possible involvement of the monoaminergic neurotransmitters norepinephrine, dopamine and serotonin in the maintenance of spatial working memory rats were treated with antagonists 0 or 2 hr after completing the first 4 choices in an 8 arm maze. Haloperidol (0.25-1 mg/kg), when administered 2 hr after Choice 4, produced a small but consistent impairment in performance on retention tests given 5 hr after the first 4 choices. This deficit closely resembled natural forgetting in terms of the type of errors committed. By contrast, haloperidol in the same doses given 0 hr after Choice 4 or 3 hr before the first 4 choices did not affect retention. Likewise treatment with propranolol (10-20 mg/kg), phentolamine (5-20 mg/kg) or methysergide (5-15 mg/kg) did not impair spatial memory, regardless of when these drugs were injected within the session. Evidently dopaminergic neuronal systems are important in the maintenance of normal spatial working memory.
Esteban, Laura; Vivas, Ana B.; Fuentes, Luis J.; Estévez, Angeles F.
Working memory (WM) is essential to academic achievement. Any enhancement of WM abilities may improve children’s school performance. We tested the usefulness of the differential outcomes procedure (DOP) to enhance typically developing children’s performance on a spatial WM task. The DOP involves a conditional discriminative learning task in which a correct choice response to a specific stimulus-stimulus association is reinforced with a particular reinforcer (outcome). We adapted a spatial memory task to be used with the DOP. Participants had to learn and retain in their WM four target locations of eight possible locations where a shape could be presented. Two groups of 5- and 7-year-old children performed the low-attentional version of the spatial task, and an additional group of 7-year-old children performed the high-attentional version. The results showed that compared with the standard non-differential outcomes procedure (NOP), the DOP produced better memory-based performance in 5-year-old children with the low-attentional task and in 7-year-old children with the high-attentional task. Additionally, delay intervals impaired performance in the NOP but not in the DOP. These findings suggest that the DOP may be a useful complement to other WM intervention programs targeted to improve children´s academic performance at school. PMID:26596777
Ando, J; Ono, Y; Wright, M J
Working memory (WM) encompasses both short-term memory (storage) and executive functions that play an essential role in all forms of cognition. In this study, the genetic structure of storage and executive functions engaged in both a spatial and verbal WM span task is investigated using a twin sample. The sample consists of 143 monozygotic (MZ) and 93 dizygotic (DZ) Japanese twin pairs, ages 16 to 29 years. In 155 (87 MZ, 62 DZ) of these pairs, cognitive ability scores from the Kyodai Japanese IQ test are also obtained. The phenotypic relationship between WM and cognitive ability is confirmed (r = 0.26-0.44). Individual differences in WM storage and executive functions are found to be significantly influenced by genes, with heritability estimates all moderately high (43%-49%), and estimates for cognitive ability comparable to previous studies (65%). A large part of the genetic variance in storage and executive functions in both spatial and verbal modalities is due to a common genetic factor that accounts for 11% to 43% of the variance. In the reduced sample, this common genetic factor accounts for 64% and 26% of the variance in spatial and verbal cognitive ability, respectively. Additional genetic variance in WM (7%-30%) is due to modality specific factors (spatial and verbal) and a storage specific factor that may be particularly important for the verbal modality. None of the variance in cognitive ability is accounted for by the modality and storage genetic factors, suggesting these may be specific to WM.
Background Memory retrieval is not a passive process. Recent studies have shown that reactivated memory is destabilized and then restabilized through gene expression-dependent reconsolidation. Molecular studies on the regulation of memory stability after retrieval have focused almost exclusively on fear memory, especially on the restabilization process of the reactivated fear memory. We previously showed that, similarly with fear memories, reactivated spatial memory undergoes reconsolidation in the Morris water maze. However, the underlying molecular mechanisms by which reactivated spatial memory is destabilized and restabilized remain poorly understood. In this study, we investigated the molecular mechanism that regulates the stability of the reactivated spatial memory. Results We first showed that pharmacological inactivation of the N-methyl-D-aspartate glutamate receptor (NMDAR) in the hippocampus or genetic inhibition of cAMP-responsible element binding protein (CREB)-mediated transcription disrupted reactivated spatial memory. Finally, we showed that pharmacological inhibition of cannabinoid receptor 1 (CB1) and L-type voltage gated calcium channels (LVGCCs) in the hippocampus blocked the disruption of the reactivated spatial memory by the inhibition of protein synthesis. Conclusions Our findings indicated that the reactivated spatial memory is destabilized through the activation of CB1 and LVGCCs and then restabilized through the activation of NMDAR- and CREB-mediated transcription. We also suggest that the reactivated spatial memory undergoes destabilization and restabilization in the hippocampus, through similar molecular processes as those for reactivated contextual fear memories, which require CB1 and LVGCCs for destabilization and NMDAR and CREB for restabilization. PMID:21314917
McConnell, Sarah E A; Alla, Juliet; Wheat, Elizabeth; Romeo, Russell D; McEwen, Bruce; Thornton, Janice E
Attempts to determine the influence of testicular hormones on learning and memory in males have yielded contradictory results. The present studies examined whether testicular hormones are important for maximal levels of spatial memory in young adult male rats. To minimize any effect of stress, we used the Object Location Task which is a spatial working memory task that does not involve food or water deprivation or aversive stimuli for motivation. In Experiment 1 sham gonadectomized male rats demonstrated robust spatial memory, but gonadectomized males showed diminished spatial memory. In Experiment 2 subcutaneous testosterone (T) capsules restored spatial memory performance in gonadectomized male rats, while rats with blank capsules demonstrated compromised spatial memory. In Experiment 3, gonadectomized male rats implanted with blank capsules again showed compromised spatial memory, while those with T, dihydrotestosterone (DHT), or estradiol (E) capsules demonstrated robust spatial memory, indicating that T's effects may be mediated by its conversion to E or to DHT. Gonadectomized male rats injected with Antide, a gonadotropin-releasing hormone receptor antagonist which lowers luteinizing hormone levels, also demonstrated spatial memory, comparable to that shown by T-, E-, or DHT-treated males. These data indicate that testicular androgens are important for maximal levels of spatial working memory in male rats, that testosterone may be converted to E and/or DHT to exert its effects, and that some of the effects of these steroid hormones may occur via negative feedback effects on LH.
Place, Ryan; Lykken, Christy; Beer, Zachery; Suh, Junghyup; McHugh, Thomas J.; Tonegawa, Susumu; Eichenbaum, Howard; Sauvage, Magdalena M.
Recent studies focusing on the memory for temporal order have reported that CA1 plays a critical role in the memory for the sequences of events, in addition to its well-described role in spatial navigation. In contrast, CA3 was found to principally contribute to the memory for the association of items with spatial or contextual information in…
Bedard, Anne-Claude; Martinussen, Rhonda; Ickowicz, Abel; Tannock, Rosemary
Objective: To investigate the effect of methylphenidate (MPH) on visual-spatial memory, as measured by subtests of the Cambridge Neuropsychological Testing Automated Battery (CANTAB), in children with attention-deficit/hyperactivity disorder (ADHD). Visual-spatial memory is a core component of working memory that has been shown to be impaired in…
Ramirez, Gerardo; Gunderson, Elizabeth A; Levine, Susan C; Beilock, Sian L
Spatial ability is a strong predictor of students' pursuit of higher education in science and mathematics. However, very little is known about the affective factors that influence individual differences in spatial ability, particularly at a young age. We examine the role of spatial anxiety in young children's performance on a mental rotation task. We show that even at a young age, children report experiencing feelings of nervousness at the prospect of engaging in spatial activities. Moreover, we show that these feelings are associated with reduced mental rotation ability among students with high but not low working memory (WM). Interestingly, this WM × spatial anxiety interaction was only found among girls. We discuss these patterns of results in terms of the problem-solving strategies that boys versus girls use in solving mental rotation problems.
Gmeindl, Leon; Courtney, Susan M.
Objective To investigate whether spatial working memory (WM) is impaired in multiple sclerosis (MS), and, if it is, to localize impairment to specific cognitive subprocess(es). Method In Experiment 1, MS and control participants performed computerized memory-span and visuomotor tasks. WM subprocesses were taxed by manipulating (1) the requirement to remember serial order, (2) delay duration, and (3) the presence of irrelevant stimuli during target presentation. In Experiment 2, recall and recognition tests varied the difficulty of WM retrieval. In Experiment 3, an attention-cueing task tested the ability to voluntarily and rapidly reorient attention. Results Performance was worse for MS than for control participants in both spatial recall (Exp. 1 span: 95% CIMS = [5.11, 5.57], 95% CIControls = [5.58, 6.03], p = 0.003, 1-tailed; Exp. 2 span: 95% CIMS = [4.44, 5.54], 95% CIControls = [5.47, 6.57], p = 0.006, 1-tailed) and recognition (accuracy: 95% CIMS = [0.71, 0.81], 95% CIControls = [0.79, 0.88], p = 0.01, 1-tailed) tests. However, there was no evidence for deficits in spatiotemporal binding, maintenance, retrieval, distractor suppression, or visuomotor processing. In contrast, MS participants were abnormally slow to reorient attention (cueing effect (ms): 95% CIMS: [90, 169], 95% CIControls: [29, 107], p = 0.015, 1-tailed). Conclusions Results suggest that, whereas spatial WM is impaired in MS, once spatial information has been adequately encoded into WM, individuals with MS are, on average, able to maintain and retrieve this information. Impoverished encoding of spatial information, however, may be due to inefficient voluntary orienting of attention. PMID:22059650
Gervais, Nicole J; Barrett-Bernstein, Meagan; Sutherland, Robert J; Mumby, Dave G
Anatomical and electrophysiological evidence suggest the dorsolateral entorhinal cortex (DLEC) is involved in processing spatial information, but there is currently no consensus on whether its functions are necessary for normal spatial learning and memory. The present study examined the effects of excitotoxic lesions of the DLEC on retrograde and anterograde memory on two tests of allocentric spatial learning: a hidden fixed-platform watermaze task, and a novelty-preference-based dry-maze test. Deficits were observed on both tests when training occurred prior to but not following n-methyl d-aspartate (NMDA) lesions of DLEC, suggesting retrograde memory impairment in the absence of anterograde impairments for the same information. The retrograde memory impairments were temporally-graded; rats that received DLEC lesions 1-3 days following training displayed deficits, while those that received lesions 7-10 days following training performed like a control group that received sham surgery. The deficits were not attenuated by co-infusion of tetrodotoxin, suggesting they are not due to disruption of neural processing in structures efferent to the DLEC, such as the hippocampus. The present findings provide evidence that the DLEC is involved in the consolidation of allocentric spatial information.
Sprague, Thomas C; Ester, Edward F; Serences, John T
Summary Working memory (WM) enables the maintenance and manipulation of information relevant to behavioral goals. Variability in WM ability is strongly correlated with IQ  and WM function is impaired in many neurological and psychiatric disorders [2, 3], suggesting that this system is a core component of higher cognition. WM storage is thought to be mediated by patterns of activity in neural populations selective for specific properties (e.g., color, orientation, location, motion direction) of memoranda [4–13]. Accordingly, many models propose that differences in the amplitude of these population responses should be related to differences in memory performance [14, 15]. Here, we used functional magnetic resonance imaging (fMRI) and an image reconstruction technique based on a spatial encoding model  to visualize and quantify population-level memory representations supported by multivoxel patterns of activation within regions of occipital, parietal and frontal cortex while participants precisely remembered the location(s) of 0, 1, or 2 small stimuli. We successfully reconstructed images containing representations of the remembered – but not forgotten – locations within regions of occipital, parietal, and frontal cortex using delay-period activation patterns. Critically, the amplitude of representations of remembered locations and behavioral performance both decreased with increasing memory load. These results suggest that differences in visual WM performance between memory load conditions are mediated by changes in the fidelity of large-scale population response profiles distributed across multiple areas of human cortex. PMID:25201683
Langley, C M
Desert kangaroo rats (Dipodomys deserti) forage for seed distributed in patches in the desert environment and may remember patch locations. In Experiment 1, 7 desert kangaroo rats that had discovered the location of a plastic token in 1 box accurately dug for a token hidden in the same location in a 2nd identical box. Results of Experiment 2 indicated that the rats primarily remembered the spatial location of the token within the box in relation to extramaze objects and the walls of the experimental box. Female rats also remembered the chip's location in relation to objects inside the box, but males did not. Experiment 3 demonstrated that the rats' ability to locate the buried token did not depend on detection of the odor of the token. In the discussion I propose that spatial memory in kangaroo rats may have evolved as a result of an overall change in the ontogeny of the species rather than as a specialized adaptation for foraging efficiency.
Le Séac'h, Anne Brec'hed; Senot, Patrice; McIntyre, Joseph
When programming movement, one must account for gravitational acceleration. This is particularly important when catching a falling object because the task requires a precise estimate of time-to-contact. Knowledge of gravity's effects is intimately linked to our definition of 'up' and 'down'. Both directions can be described in an allocentric reference frame, based on visual and/or gravitational cues, or in an egocentric reference frame in which the body axis is taken as vertical. To test which frame humans use to predict gravity's effect, we asked participants to intercept virtual balls approaching from above or below with artificially controlled acceleration that could be congruent or not with gravity. To dissociate between these frames, subjects were seated upright (trunk parallel to gravity) or lying down (body axis orthogonal to the gravitational axis). We report data in line with the use of an allocentric reference frame and discuss its relevance depending on available gravity-related cues.
Alain, Claude; Shen, Dawei; Yu, He; Grady, Cheryl
Attending and responding to sound location generates increased activity in parietal cortex which may index auditory spatial working memory and/or goal-directed action. Here, we used an n-back task (Experiment 1) and an adaptation paradigm (Experiment 2) to distinguish memory-related activity from that associated with goal-directed action. In Experiment 1, participants indicated, in separate blocks of trials, whether the incoming stimulus was presented at the same location as in the previous trial (1-back) or two trials ago (2-back). Prior to a block of trials, participants were told to use their left or right index finger. Accuracy and reaction times were worse for the 2-back than for the 1-back condition. The analysis of functional magnetic resonance imaging data revealed greater sustained task-related activity in the inferior parietal lobule (IPL) and superior frontal sulcus during 2-back than 1-back after accounting for response-related activity elicited by the targets. Target detection and response execution were also associated with enhanced activity in the IPL bilaterally, though the activation was anterior to that associated with sustained task-related activity. In Experiment 2, we used an event-related design in which participants listened (no response required) to trials that comprised four sounds presented either at the same location or at four different locations. We found larger IPL activation for changes in sound location than for sounds presented at the same location. The IPL activation overlapped with that observed during the auditory spatial working memory task. Together, these results provide converging evidence supporting the role of parietal cortex in auditory spatial working memory which can be dissociated from response selection and execution. PMID:21833258
Ross, A P; Bartness, T J; Mielke, J G; Parent, M B
Over the past three decades there has been a substantial increase in the amount of fructose consumed by North Americans. Recent evidence from rodents indicates that hippocampal insulin signaling facilitates memory and excessive fructose consumption produces hippocampal insulin resistance. Based on this evidence, the present study tested the hypothesis that a high fructose diet would impair hippocampal-dependent memory. Adult male Sprague-Dawley rats (postnatal day 61) were fed either a control (0% fructose) or high fructose diet (60% of calories). Food intake and body mass were measured regularly. After 19 weeks, the rats were given 3 days of training (8 trials/day) in a spatial version of the water maze task, and retention performance was probed 48 h later. The high fructose diet did not affect acquisition of the task, but did impair performance on the retention test. Specifically, rats fed a high fructose diet displayed significantly longer latencies to reach the area where the platform had been located, made significantly fewer approaches to that area, and spent significantly less time in the target quadrant than did control diet rats. There was no difference in swim speed between the two groups. The retention deficits correlated significantly with fructose-induced elevations of plasma triglyceride concentrations. Consequently, the impaired spatial water maze retention performance seen with the high fructose diet may have been attributable, at least in part, to fructose-induced increases in plasma triglycerides.
DeMaster, Dana; Pathman, Thanujeni; Ghetti, Simona
The goal of the present study was to examine age-related differences in hippocampal and cortical contribution to episodic retrieval of spatial context in 3 age groups. Children ages 8-9 and 10-11 years old, and adults ages 18-25 (N=48) encoded black and white line drawings appearing either on the right side or the left side of a screen. Functional magnetic resonance imaging (fMRI) data were acquired while participants attempted to recall where each studied drawing had originally appeared. Correct recall of spatial source indicated successful episodic retrieval of spatial context. Activity in head and body of the hippocampus was associated with episodic retrieval in adults, but not in children. In children, individual differences in hippocampal activation for recognition predicted rates of correct spatial recall. Developmental differences were also found in regions in posterior parietal cortex, anterior prefrontal cortex, and insula. Overall, these results support the view that the development of episodic memory is supported by functional changes in the hippocampus as well as cortical regions.
Bottini, Roberto; Mattioni, Stefania; Collignon, Olivier
Several studies suggest that serial order in working memory (WM) is grounded on space. For a list of ordered items held in WM, items at the beginning of the list are associated with the left side of space and items at the end of the list with the right side. This suggests that maintaining items in verbal WM is performed in strong analogy to writing these items down on a physical whiteboard for later consultation (The Mental Whiteboard Hypothesis). What drives this spatial mapping of ordered series in WM remains poorly understood. In the present study we tested whether visual experience is instrumental in establishing the link between serial order in WM and spatial processing. We tested early blind (EB), late blind (LB) and sighted individuals in an auditory WM task. Replicating previous studies, left-key responses were faster for early items in the list whereas later items facilitated right-key responses in the sighted group. The same effect was observed in LB individuals. In contrast, EB participants did not show any association between space and serial position in WM. These results suggest that early visual experience plays a critical role in linking ordered items in WM and spatial representations. The analogical spatial structure of WM may depend in part on the actual experience of using spatially organized devices (e.g., notes, whiteboards) to offload WM. These practices are largely precluded to EB individuals, who instead rely to mnemonic devices that are less spatially organized (e.g., recordings, vocal notes). The way we habitually organize information in the external world may bias the way we organize information in our WM.
Smith, S T; Stackman, R W; Clark, A S
The effects of anabolic-androgenic steroid (AAS) compounds on spatial working memory were evaluated in male rats. Thirty days of administration of a high dose of three individual AAS compounds (17 alpha-methyltestosterone, methandrostenolone, or testosterone cypionate) had no effects on spatial memory or motivation as tested on a delayed non-match-to-sample radial arm maze task. Administration of these AAS compounds at doses within the human abuse range does not impair spatial working memory in rats.
Milton, Russell; Babichev, Andrey; Dabaghian, Yuri
In the hippocampus, a network of place cells generates a cognitive map of space, in which each cell is responsive to a particular area of the environment - its place field. The peak response of each cell and the size of each place field have considerable variability. Experimental evidence suggests that place cells encode a topological map of space that serves as a basis of spatial memory and spatial awareness. Using a computational model based on Persistent Homology Theory we demonstrate that if the parameters of the place cells spiking activity fall inside of the physiological range, the network correctly encodes the topological features of the environment. We next introduce parameters of synaptic connectivity into the model and demonstrate that failures in synapses that detect coincident neuronal activity lead to spatial learning deficiencies similar to the ones that are observed in rodent models of neurodegenerative diseases. Moreover, we show that these learning deficiencies may be mitigated by increasing the number of active cells and/or by increasing their firing rate, suggesting the existence of a compensatory mechanism inherent to the cognitive map.
Hassanpoor, Hossein; Fallah, Ali; Raza, Mohsin
Our knowledge about encoding and maintenance of spatial memory emphasizes the integrated functional role of the grid cells and the place cells of the hippocampus in the generation of theta rhythm in spatial memory formation. However, the role of astrocytes in these processes is often underestimated in their contribution to the required structural and functional characteristics of hippocampal neural network operative in spatial memory. We show that hippocampal astrocytes, by the secretion of gliotransmitters, such as glutamate, d-serine, and ATP and growth factors such as BDNF and by the expression of receptors and channels such as those of TNFα and aquaporin, have several diverse fuctions in spatial memory. We specifically focus on the role of astrocytes on five phases of spatial memory: (1) theta rhythm generation, (2) theta phase precession, (3) formation of spatial memory by mapping data of entorhinal grid cells into the place cells, (4) storage of spatial information, and (5) maintenance of spatial memory. Finally, by reviewing the literature, we propose specific mechanisms mentioned in the form of a hypothesis suggesting that astrocytes are important in spatial memory formation.
Sapiurka, Maya; Squire, Larry R; Clark, Robert E
In earlier work, patients with hippocampal damage successfully path integrated, apparently by maintaining spatial information in working memory. In contrast, rats with hippocampal damage were unable to path integrate, even when the paths were simple and working memory might have been expected to support performance. We considered possible ways to understand these findings. We tested rats with either hippocampal lesions or lesions of medial prefrontal cortex (mPFC) on three tasks of spatial or nonspatial memory: path integration, spatial alternation, and a nonspatial alternation task. Rats with mPFC lesions were impaired on both spatial and nonspatial alternation but performed normally on path integration. By contrast, rats with hippocampal lesions were impaired on path integration and spatial alternation but performed normally on nonspatial alternation. We propose that rodent neocortex is limited in its ability to construct a coherent spatial working memory of complex environments. Accordingly, in tasks such as path integration and spatial alternation, working memory cannot depend on neocortex alone. Rats may accomplish many spatial memory tasks by relying on long-term memory. Alternatively, they may accomplish these tasks within working memory through sustained coordination between hippocampus and other cortical brain regions such as mPFC, in the case of spatial alternation, or parietal cortex in the case of path integration. © 2016 Wiley Periodicals, Inc.
Besnard, S; Machado, M L; Vignaux, G; Boulouard, M; Coquerel, A; Bouet, V; Freret, T; Denise, P; Lelong-Boulouard, V
It has recently been shown that a lack of vestibular sensory information decreases spatial memory performance and induces biochemical changes in the hippocampus in rodents. After vestibular neurectomy, patients display spatial memory deficit and hippocampal atrophy. Our objectives were to explore: (a) spatial (Y maze, radial-arm maze), and non-spatial (object recognition) memory performance, (b) modulation of NMDA receptors within the hippocampus using radioligand binding, and (c) hippocampal atrophy, using MRI, in a rat model of bilateral labyrinthectomy realized in two operations. Chemical vestibular lesions (VLs) were induced in 24 animals by transtympanic injections of sodium arsanilate (30 mg/0.1 ml/ear), one side being lesioned 3 weeks after the other. The control group received transtympanic saline solution (0.1 ml/ear) (n = 24). Spatial memory performance (Y maze and radial maze) decreased after VL. Conversely, non-spatial memory performance (object recognition) was not affected by VL. No hippocampal atrophy was observed with MRI, but density of NMDA receptors were increased in the hippocampus after VL. These findings show that the lack of vestibular information induced specific deficits in spatial memory. Additionally, quantitative autoradiographic data suggest the involvement of the glutamatergic system in spatial memory processes related to vestibular information. When studying spatial memory performances in the presence of vestibular syndrome, two-step labyrinthectomy is a suitable procedure for distinguishing between the roles of the specific components of vestibular input loss and those of impaired locomotor activity.
Wang, Lu; Carr, Martha
In this review, a new model that is grounded in information-processing theory is proposed to account for gender differences in spatial ability. The proposed model assumes that the relative strength of working memory, as expressed by the ratio of visuospatial working memory to verbal working memory, influences the type of strategies used on spatial…
Sekeres, Melanie J.; Neve, Rachael L.; Frankland, Paul W.; Josselyn, Sheena A.
Although the transcription factor CREB has been widely implicated in memory, whether it is sufficient to produce spatial memory under conditions that do not normally support memory formation in mammals is unknown. We found that locally and acutely increasing CREB levels in the dorsal hippocampus using viral vectors is sufficient to induce robust…
Lim, Sukbin; Goldman, Mark S
A hallmark of working memory is the ability to maintain graded representations of both the spatial location and amplitude of a memorized stimulus. Previous work has identified a neural correlate of spatial working memory in the persistent maintenance of spatially specific patterns of neural activity. How such activity is maintained by neocortical circuits remains unknown. Traditional models of working memory maintain analog representations of either the spatial location or the amplitude of a stimulus, but not both. Furthermore, although most previous models require local excitation and lateral inhibition to maintain spatially localized persistent activity stably, the substrate for lateral inhibitory feedback pathways is unclear. Here, we suggest an alternative model for spatial working memory that is capable of maintaining analog representations of both the spatial location and amplitude of a stimulus, and that does not rely on long-range feedback inhibition. The model consists of a functionally columnar network of recurrently connected excitatory and inhibitory neural populations. When excitation and inhibition are balanced in strength but offset in time, drifts in activity trigger spatially specific negative feedback that corrects memory decay. The resulting networks can temporally integrate inputs at any spatial location, are robust against many commonly considered perturbations in network parameters, and, when implemented in a spiking model, generate irregular neural firing characteristic of that observed experimentally during persistent activity. This work suggests balanced excitatory-inhibitory memory circuits implementing corrective negative feedback as a substrate for spatial working memory.
A hallmark of working memory is the ability to maintain graded representations of both the spatial location and amplitude of a memorized stimulus. Previous work has identified a neural correlate of spatial working memory in the persistent maintenance of spatially specific patterns of neural activity. How such activity is maintained by neocortical circuits remains unknown. Traditional models of working memory maintain analog representations of either the spatial location or the amplitude of a stimulus, but not both. Furthermore, although most previous models require local excitation and lateral inhibition to maintain spatially localized persistent activity stably, the substrate for lateral inhibitory feedback pathways is unclear. Here, we suggest an alternative model for spatial working memory that is capable of maintaining analog representations of both the spatial location and amplitude of a stimulus, and that does not rely on long-range feedback inhibition. The model consists of a functionally columnar network of recurrently connected excitatory and inhibitory neural populations. When excitation and inhibition are balanced in strength but offset in time, drifts in activity trigger spatially specific negative feedback that corrects memory decay. The resulting networks can temporally integrate inputs at any spatial location, are robust against many commonly considered perturbations in network parameters, and, when implemented in a spiking model, generate irregular neural firing characteristic of that observed experimentally during persistent activity. This work suggests balanced excitatory–inhibitory memory circuits implementing corrective negative feedback as a substrate for spatial working memory. PMID:24828633
Rensel, M A; Salwiczek, L; Roth, J; Schlinger, B A
Estradiol is known to impact cognitive function including spatial learning and memory, with studies focused largely on rodent models. Estrogens can be produced peripherally or centrally as neuroestrogens, and the specific role for neuroestrogens in memory processes remains unresolved. Many songbirds possess remarkable spatial memory capabilities and also express the estrogen synthetic enzyme aromatase abundantly in the hippocampus, suggesting that locally-produced estrogens may promote the acquisition or retrieval of spatial memories in these birds. We examined the effect of estradiol on spatial memory in three contexts in the zebra finch: retrieval after discrimination training, retrieval after familiarization but without discrimination training, and memory acquisition, using a combination of estradiol implants and oral dosing with the aromatase inhibitor fadrozole (FAD). Retrieval of spatial memory in both contexts was impaired when estradiol production was blocked. However, spatial memory acquisition was enhanced when estradiol production was inhibited whereas estradiol replacement impaired acquisition. These results provide evidence for a context-specific role of estradiol in songbird spatial memory, results that find accord with some mammalian studies but have not yet been observed in birds.
Guenzel, Friederike M; Wolf, Oliver T; Schwabe, Lars
Stress and stress hormones are known to affect learning and memory processes. However, although effects of stress on hippocampus-dependent declarative learning and memory are well-documented, relatively little attention has been paid to the impact of stress on striatum-dependent stimulus-response (S-R) learning and memory. Recent evidence indicates that glucocorticoid stress hormones shortly after learning enhance S-R memory consolidation, whereas stress prior to retention testing impairs S-R memory retrieval. Whether stress affects also the acquisition of S-R memories in humans remains unclear. For this reason, we examined here the effects of acute stress on S-R memory formation and contrasted these stress effects with those on hippocampus-dependent spatial memory. Healthy men and women underwent a stressor (socially evaluated cold pressor test, SECPT) or a control manipulation before they completed an S-R task and two spatial learning tasks. Memory was assessed one week later. Our data showed that stress impaired S-R memory performance in men but not in women. Conversely, spatial memory was impaired by stress in women but not in men. These findings provide further evidence that stress may alter learning and memory processes beyond the hippocampus. Moreover, our data underline that participants' sex may play a critical role in the impact of stress on multiple memory systems.
Morey, Candice C.; Miron, Monica D.
Among models of working memory, there is not yet a consensus about how to describe functions specific to storing verbal or visual-spatial memories. We presented aural-verbal and visual-spatial lists simultaneously and sometimes cued one type of information after presentation, comparing accuracy in conditions with and without informative…
Luna, David; Martínez, Héctor
The occurrence of spontaneous recovery in human spatial memory was assessed using a virtual environment. In Experiment 1, spatial memory was established by training participants to locate a hidden platform in a virtual water maze using a set of four distal landmarks. In Experiment 2, after learning about the location of a hidden platform, the…
Robin, Jessica; Moscovitch, Morris
Several recent studies have explored the effect of contextual familiarity on remembered and imagined events. The aim of this study was to examine the extent of this effect by comparing the effect of cuing spatial memories, episodic memories, and imagined future events with spatial contextual cues of varying levels of familiarity. We used…
Yerramsetti, Ashok; Marchette, Steven A.; Shelton, Amy L.
Orientation dependence in spatial memory has often been interpreted in terms of accessibility: Object locations are encoded relative to a reference orientation that affords the most accurate access to spatial memory. An open question, however, is whether people naturally use this "preferred" orientation whenever recalling the space. We…
Brunye, Tad T.; Taylor, Holly A.
Four dual-task experiments examined visuospatial, articulatory, and central executive working memory involvement during the development and application of spatial mental models. In Experiments 1 and 2 participants read route and survey spatial descriptions while undertaking one of four secondary tasks targeting working memory components.…
Morey, Candice C; Mall, Jonathan T
Some evidence suggests that memory for serial order is domain-general. Evidence also points to asymmetries in interference between verbal and visual-spatial tasks. We confirm that concurrently remembering verbal and spatial serial lists provokes substantial interference compared with remembering a single list, but we further investigate the impact of this interference throughout the serial position curve, where asymmetries are indeed apparent. A concurrent verbal order memory task affects spatial memory performance throughout the serial positions of the list, but performing a spatial order task affects memory for the verbal serial list only for early list items; in the verbal task only, the final items are unaffected by a concurrent task. Adding suffixes eliminates this asymmetry, resulting in impairment throughout the list for both tasks. These results suggest that domain-general working memory resources may be supplemented with resources specific to the verbal domain, but perhaps not with equivalent spatial resources.
Lavenex, Pamela Banta; Amaral, David G; Lavenex, Pierre
The role of the hippocampus in spatial learning and memory has been extensively studied in rodents. Comparable studies in nonhuman primates, however, are few, and findings are often contradictory. This may be attributable to the failure to distinguish between allocentric and egocentric spatial representations in experimental designs. For this experiment, six adult monkeys received bilateral hippocampal ibotenic acid lesions, and six control subjects underwent sham surgery. Freely moving monkeys then foraged for food located in two arrays of three distinct locations among 18 locations distributed in an open-field arena. Multiple goals and four pseudorandomly chosen entrance points precluded the monkeys' ability to rely on an egocentric strategy to identify food locations. Monkeys were tested in two conditions. First, local visual cues marked the food locations. Second, no local cues marked the food locations, so that monkeys had to rely on an allocentric (spatial relational) representation of the environment to discriminate these locations. Both hippocampal-lesioned and control monkeys discriminated the food locations in the presence of local cues. However, in the absence of local cues, control subjects discriminated the food locations, whereas hippocampal-lesioned monkeys were unable to do so. Interestingly, histological analysis of the brain of one control monkey whose behavior was identical to that of the experimentally lesioned animals revealed a bilateral ischemic lesion restricted to the hippocampus. These findings demonstrate that the adult monkey hippocampal formation is critical for the establishment or use of allocentric spatial representations and that selective damage of the hippocampus prevents spatial relational learning in adult nonhuman primates.
Wartman, Brianne C.; Gabel, Jennifer; Holahan, Matthew R.
One system consolidation model suggests that as time passes, ensembles of cortical neurons form strong connections to represent remote memories. In this model, the anterior cingulate cortex (ACC) serves as a cortical region that represents remote memories. However, there is debate as to whether remote spatial memories go through this systems consolidation process and come to rely on the ACC. The present experiment examined whether increasing the processing demand on the hippocampus, by sequential training on two spatial tasks, would more fully engage the ACC during retrieval of a remote spatial memory. In this scenario, inactivation of the ACC at a remote time point was hypothesized to produce a severe memory deficit if rats had been trained on two, sequential spatial tasks. Rats were trained on a water maze (WM) task only or a WM task followed by a radial arm maze task. A WM probe test was given recently or remotely to all rats. Prior to the probe test, rats received an injection of saline or muscimol into the ACC. A subtle deficit in probe performance was found at the remote time point in the group trained on only one spatial task and treated with muscimol. In the group trained on two spatial tasks and treated with muscimol, a subtle deficit in probe performance was noted at the recent time point and a substantial deficit in probe performance was observed at the remote time point. c-Fos labeling in the hippocampus revealed more labeling in the CA1 region in all remotely tested groups than recently tested groups. Findings suggest that spatial remote memories come to rely more fully on the ACC when hippocampal processing requirements are increased. Results also suggest continued involvement of the hippocampus in spatial memory retrieval along with a progressive strengthening of cortical connections as time progresses. PMID:25279556
Li, Lin; Sase, Ajinkya; Patil, Sudarshan; Sunyer, Berta; Höger, Harald; Smalla, Karl-Heinz; Stork, Oliver; Lubec, Gert
Protein phosphorylation and dephosphorylation events play a key role in memory formation and various protein kinases and phosphatases have been firmly associated with memory performance. Here, we determined expression changes of protein kinases and phosphatases following retrieval of spatial memory in CD1 mice in a Morris Water Maze task, using antibody microarrays and confirmatory Western blot. Comparing changes following single and consecutive retrieval, we identified stably and differentially expressed kinases, some of which have never been implicated before in memory functions. On the basis of these findings we define a small signaling network associated with spatial memory retrieval. Moreover, we describe differential regulation and correlation of expression levels with behavioral performance of polo-like kinase 1. Together with its recently observed genetic association to autism-spectrum disorders our data suggest a role of this kinase in balancing preservation and flexibility of learned behavior.
Kreitz, Carina; Furley, Philip; Memmert, Daniel; Simons, Daniel J
Working memory and attention are closely related constructs. Models of working memory often incorporate an attention component, and some even equate working memory and attentional control. Although some attention-related processes, including inhibitory control of response conflict and interference resolution, are strongly associated with working memory, for other aspects of attention the link is less clear. We examined the association between working-memory performance and attentional breadth, the ability to spread attention spatially. If the link between attention and working memory is broader than inhibitory and interference resolution processes, then working-memory performance might also be associated with other attentional abilities, including attentional breadth. We tested 123 participants on a variety of working-memory and attentional-breadth measures, finding a strong correlation between performances on these two types of tasks. This finding demonstrates that the link between working memory and attention extends beyond inhibitory processes.
Thompson, Aidan A; Henriques, Denise Y P
In this review we discuss evidence from psychophysical, electrophysiological, and neuroimaging studies that demonstrates the updating of remembered visual space in a reference frame that is centred on the eye. We then extend these findings by discussing recent work from our lab. Specifically, we address eye-centred updating of visuospatial memory for arm movements following different types of eye movements, the role of retinal versus extraretinal information in such spatial updating, and the use of allocentric versus egocentric information in coding multiple targets. We provide a conceptual model to explain the relationships among these findings.
Byagowi, Ahmad; Moussavi, Zahra
Virtual reality (VR) experiments are commonly used to assess human brain functions. We orient ourselves in an environment by computing precise self-to-object spatial relations (egocentric orientation) as well as object-to-object spatial relations (allocentric orientation). Egocentric orientation involves cues that depend on the position of the observer (i.e. left-right, front-behind), whereas allocentric orientation is maintained through the use of environmental features such as landmarks. As such, allocentric orientation involves short-term memory, whereas egocentric orientation does not. This paper presents a Virtual Reality Navigational (VRN) experiment specifically designed to assess egocentric spatial cognition. The design aimed to minimize the effect of spatial cues or landmarks for human navigation in a naturalistic VR environment. The VRN experiment designed for this study, called the Virtual House, is a symmetric three story cubic building, with 3 windows on each side on every floor, and one entrance on each side of the building. In each trial, a window is marked by a pseudo-random sequence as the objective. The marked window is shown to the participant from an outdoor view. The task is to reach the objective window using the shortest path through the building. The experiment entails 2 sets of 8 trials to cover all possibilities. The participants' performance error is measured by the difference between their traversed distance trajectory and the shortest natural distance (calculated using the VR engine), normalized by the shortest distance, in each trial. Fifty-two cognitively healthy adults participated in the study. The results show no learning effect during the 16 trails, implying that the experiment does not rely on short-term memory. Furthermore, the subjects' normalized performance error showed an almost linear increase with age, implying that egocentric spatial cognition ability declines with age.
Nelson, Andrew J. D.; Powell, Anna L.; Holmes, Joshua D.; Vann, Seralynne D.; Aggleton, John P.
The retrosplenial cortex supports navigation, but there are good reasons to suppose that the retrosplenial cortex has a very different role in spatial memory from that of the hippocampus and anterior thalamic nuclei. For example, retrosplenial lesions appear to have little or no effect on standard tests of spatial alternation. To examine these differences, the current study sought to determine whether the retrosplenial cortex is important for just one spatial cue type (e.g., allocentric, directional or intra-maze cues) or whether the retrosplenial cortex helps the animal switch between competing spatial strategies or competing cue types. Using T-maze alternation, retrosplenial lesion rats were challenged with situations in which the available spatial information between the sample and test phases was changed, so taxing the interaction between different cue types. Clear lesion deficits emerged when intra- and extra-maze cues were placed in conflict (by rotating the maze between the sample and choice phases), or when the animals were tested in the dark in a double-maze. Finally, temporary inactivation of the retrosplenial cortex by muscimol infusions resulted in a striking deficit on standard T-maze alternation, indicating that, over time, other sites may be able to compensate for the loss of the retrosplenial cortex. This pattern of results is consistent with the impoverished use of both allocentric and directional information, exacerbated by an impaired ability to switch between different cue types. PMID:26042009
Allen, Kevin; Fuchs, Elke C; Jaschonek, Hannah; Bannerman, David M; Monyer, Hannah
Gap junctions containing connexin 36 electrically couple interneurons in many brain regions and synchronize their activity. We used connexin-36 knock-out mice (Cx36(-/-)) to study the importance of electrical coupling between interneurons for spatial coding in the hippocampus and for different forms of hippocampus-dependent spatial memory. Recordings in behaving mice revealed that the spatial selectivity of hippocampal pyramidal neurons was reduced and less stable in Cx36(-/-) mice. Altered network activity was reflected in slower theta oscillations in the mutants. Temporal coding, assessed by determining the presence and characteristics of theta phase precession, had different dynamics in Cx36(-/-) mice compared with controls. At the behavioral level, Cx36(-/-) mice displayed impaired short-term spatial memory but normal spatial reference memory. These results highlight the functional role of electrically coupled interneurons for spatial coding and cognition. Moreover, they suggest that the precise spatial selectivity of place cells is not essential for normal performance on spatial tasks assessing associative long-term memory.
Hulgard, Katrine; Ratcliffe, John M
Related species with different diets are predicted to rely on different cognitive strategies: those best suited for locating available and appropriate foods. Here we tested two predictions of the niche-specific cognitive strategies hypothesis in bats, which suggests that predatory species should rely more on object memory than on spatial memory for finding food and that the opposite is true of frugivorous and nectivorous species. Specifically, we predicted that: (1) predatory bats would readily learn to associate shapes with palatable prey and (2) once bats had made such associations, these would interfere with their subsequent learning of a spatial memory task. We trained free-flying Myotis nattereri to approach palatable and unpalatable insect prey suspended below polystyrene objects. Experimentally naïve bats learned to associate different objects with palatable and unpalatable prey but performed no better than chance in a subsequent spatial memory experiment. Because experimental sequence was predicted to be of consequence, we introduced a second group of bats first to the spatial memory experiment. These bats learned to associate prey position with palatability. Control trials indicated that bats made their decisions based on information acquired through echolocation. Previous studies have shown that bat species that eat mainly nectar and fruit rely heavily on spatial memory, reflecting the relative consistency of distribution of fruit and nectar compared with insects. Our results support the niche-specific cognitive strategies hypothesis and suggest that for gleaning and clutter-resistant aerial hawking bats, learning to associate shape with food interferes with subsequent spatial memory learning.
Haeri, Narges-Al-Sadat; Palizvan, Mohammad Reza; Sadegh, Mehdi; Aghaei, Zohre; Rafiei, Mohammad
Epilepsy is a common neurological disease characterized by periodic seizures. Cognitive deficits and impairments in learning and memory are also associated with epilepsy. Neuronal changes and synaptic modifications in kindling model of epilepsy are similar to those occur during the learning procedure and memory formation. Herein we investigated whether seizure susceptibility in pentylenetetrazol (PTZ) model of kindling is predictable based on the learning ability in the Morris water maze (MWM) task in male and female rats. Allocentric learning was tested using MWM in present of light while egocentric learning was evaluated by MWM in dark room. The results indicated no significant differences in allocentric learning abilities between male and female rats. However, male rats were able to memorize the location of the platform more effectively compared to females in egocentric test. In addition, a statistically significant negative correlation between learning abilities (working memory) and seizure susceptibility in male rats was found while this correlation was positive in female rats. On the other hand, although there was no significant correlation between retrieval (reference memory) of spatial memories and seizure parameters in male rats, female rats showed a significant negative correlation. These findings may provide some evidences for prediction of seizure susceptibility according to learning ability and memory retention.
Starc, Martina; Anticevic, Alan; Repovš, Grega
Pupillometry provides an accessible option to track working memory processes with high temporal resolution. Several studies showed that pupil size increases with the number of items held in working memory; however, no study has explored whether pupil size also reflects the quality of working memory representations. To address this question, we used a spatial working memory task to investigate the relationship of pupil size with spatial precision of responses and indicators of reliance on generalized spatial categories. We asked 30 participants (15 female, aged 19-31) to remember the position of targets presented at various locations along a hidden radial grid. After a delay, participants indicated the remembered location with a high-precision joystick providing a parametric measure of trial-to-trial accuracy. We recorded participants' pupil dilations continuously during task performance. Results showed a significant relation between pupil dilation during preparation/early encoding and the precision of responses, possibly reflecting the attentional resources devoted to memory encoding. In contrast, pupil dilation at late maintenance and response predicted larger shifts of responses toward prototypical locations, possibly reflecting larger reliance on categorical representation. On an intraindividual level, smaller pupil dilations during encoding predicted larger dilations during late maintenance and response. On an interindividual level, participants relying more on categorical representation also produced larger precision errors. The results confirm the link between pupil size and the quality of spatial working memory representation. They suggest compensatory strategies of spatial working memory performance-loss of precise spatial representation likely increases reliance on generalized spatial categories.
Vergauwe, Evie; Barrouillet, Pierre; Camos, Valerie
Examinations of interference between visual and spatial materials in working memory have suggested domain- and process-based fractionations of visuo-spatial working memory. The present study examined the role of central time-based resource sharing in visuo-spatial working memory and assessed its role in obtained interference patterns. Visual and…
Chin, Vivien S; Van Skike, Candice E; Berry, Raymond B; Kirk, Roger E; Diaz-Granados, Jamie; Matthews, Douglas B
The effects of ethanol differ in adolescent and adult rats on a number of measures. The evidence of the effects of ethanol on spatial memory in adolescents and adults is equivocal. Whether adolescents are more or less sensitive to ethanol-induced impairment of spatial memory acquisition remains unclear; with regard to the effects of acute ethanol on spatial memory retrieval there is almost no research looking into any age difference. Thus, we examined the effects of acute ethanol on spatial memory in the Morris Watermaze in adolescents and adults. Allopregnanolone (ALLO) is a modulator of the GABA(A) receptor and has similar behavioral effects as ethanol. We sought to also determine the effects of allopreganolone on spatial memory in adolescent and adults. Male adolescent (post natal [PN]28-30) and adult (PN70-72) rats were trained in the Morris Watermaze for 6 days and acute doses of ethanol (saline, 1.5 and 2.0 g/kg) or ALLO (vehicle, 9 and 18 mg/kg) were administered on Day 7. A probe trial followed on Day 8. As expected, there were dose effects; higher doses of both ethanol and ALLO impaired spatial memory. However, in both the ethanol and ALLO conditions adolescents and adults had similar spatial memory impairments. The current results suggest that ethanol and ALLO both impair hippocampal-dependent spatial memory regardless of age in that once learning has occurred, ethanol or ALLO does not differentially impair the retrieval of spatial memory in adolescents and adults. Given the mixed results on the effect of ethanol on cognition in adolescent rats, additional research is needed to ascertain the factors critical for the reported differential results.
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Paleja, Meera; Girard, Todd A.; Christensen, Bruce K.
Spatial pattern separation (SPS) and spatial pattern completion (SPC) have played an increasingly important role in computational and rodent literatures as processes underlying associative memory. SPS and SPC are complementary processes, allowing the formation of unique representations and the reconstruction of complete spatial environments based…
Li, Xiaoou; Carlson, Laura A.; Mou, Weimin; Williams, Mark R.; Miller, Jared E.
A target object's location within a configuration of objects can be described by spatially relating it to a reference object that is selected from among its neighbors, with a preference for reference objects that are spatially close and aligned with the target. In the spatial memory literature, these properties of alignment and proximity are…
Heuer, Eric; Bachevalier, Jocelyne
Earlier studies in monkeys have reported mild impairment in recognition memory after nonselective neonatal hippocampal lesions. To assess whether the memory impairment could have resulted from damage to cortical areas adjacent to the hippocampus, we tested adult monkeys with neonatal focal hippocampal lesions and sham-operated controls in three recognition tasks: delayed nonmatching-to-sample, object memory span, and spatial memory span. Further, to rule out that normal performance on these tasks may relate to functional sparing following neonatal hippocampal lesions, we tested adult monkeys that had received the same focal hippocampal lesions in adulthood and their controls in the same three memory tasks. Both early and late onset focal hippocampal damage did not alter performance on any of the three tasks, suggesting that damage to cortical areas adjacent to the hippocampus was likely responsible for the recognition impairment reported by the earlier studies. In addition, given that animals with early and late onset hippocampal lesions showed object and spatial recognition impairment when tested in a visual paired comparison task, the data suggest that not all object and spatial recognition tasks are solved by hippocampal-dependent memory processes. The current data may not only help explain the neural substrate for the partial recognition memory impairment reported in cases of developmental amnesia, but they are also clinically relevant given that the object and spatial memory tasks used in monkeys are often translated to investigate memory functions in several populations of human infants and children in which dysfunction of the hippocampus is suspected.
Rauchs, Géraldine; Orban, Pierre; Schmidt, Christina; Albouy, Geneviève; Balteau, Evelyne; Degueldre, Christian; Schnackers, Caroline; Sterpenich, Virginie; Tinguely, Gilberte; Luxen, André; Maquet, Pierre; Peigneux, Philippe
It is known that sleep reshapes the neural representations that subtend the memories acquired while navigating in a virtual environment. However, navigation is not process-pure, as manifold learning components contribute to performance, notably the spatial and contextual memory constituents. In this context, it remains unclear whether post-training sleep globally promotes consolidation of all of the memory components embedded in virtual navigation, or rather favors the development of specific representations. Here, we investigated the effect of post-training sleep on the neural substrates of the consolidation of spatial and contextual memories acquired while navigating in a complex 3D, naturalistic virtual town. Using fMRI, we mapped regional cerebral activity during various tasks designed to tap either the spatial or the contextual memory component, or both, 72 h after encoding with or without sleep deprivation during the first post-training night. Behavioral performance was not dependent upon post-training sleep deprivation, neither in a natural setting that engages both spatial and contextual memory processes nor when looking more specifically at each of these memory representations. At the neuronal level however, analyses that focused on contextual memory revealed distinct correlations between performance and neuronal activity in frontal areas associated with recollection processes after post-training sleep, and in the parahippocampal gyrus associated with familiarity processes in sleep-deprived participants. Likewise, efficient spatial memory was associated with posterior cortical activity after sleep whereas it correlated with parahippocampal/medial temporal activity after sleep deprivation. Finally, variations in place-finding efficiency in a natural setting encompassing spatial and contextual elements were associated with caudate activity after post-training sleep, suggesting the automation of navigation. These data indicate that post-training sleep
Borovok, Natalia; Nesher, Elimelech; Levin, Yishai; Reichenstein, Michal; Pinhasov, Albert
Spatial memory depends on the hippocampus, which is particularly vulnerable to aging. This vulnerability has implications for the impairment of navigation capacities in older people, who may show a marked drop in performance of spatial tasks with advancing age. Contemporary understanding of long-term memory formation relies on molecular mechanisms underlying long-term synaptic plasticity. With memory acquisition, activity-dependent changes occurring in synapses initiate multiple signal transduction pathways enhancing protein turnover. This enhancement facilitates de novo synthesis of plasticity related proteins, crucial factors for establishing persistent long-term synaptic plasticity and forming memory engrams. Extensive studies have been performed to elucidate molecular mechanisms of memory traces formation; however, the identity of plasticity related proteins is still evasive. In this study, we investigated protein turnover in mouse hippocampus during long-term spatial memory formation using the reference memory version of radial arm maze (RAM) paradigm. We identified 1592 proteins, which exhibited a complex picture of expression changes during spatial memory formation. Variable linear decomposition reduced significantly data dimensionality and enriched three principal factors responsible for variance of memory-related protein levels at (1) the initial phase of memory acquisition (165 proteins), (2) during the steep learning improvement (148 proteins), and (3) the final phase of the learning curve (123 proteins). Gene ontology and signaling pathways analysis revealed a clear correlation between memory improvement and learning phase-curbed expression profiles of proteins belonging to specific functional categories. We found differential enrichment of (1) neurotrophic factors signaling pathways, proteins regulating synaptic transmission, and actin microfilament during the first day of the learning curve; (2) transcription and translation machinery, protein
Rotzer, S; Loenneker, T; Kucian, K; Martin, E; Klaver, P; von Aster, M
The underlying neural mechanisms of developmental dyscalculia (DD) are still far from being clearly understood. Even the behavioral processes that generate or influence this heterogeneous disorder are a matter of controversy. To date, the few studies examining functional brain activation in children with DD mainly focus on number and counting related tasks, whereas studies on more general cognitive domains that are involved in arithmetical development, such as working memory are virtually absent. There are several studies showing a close relationship between DD and spatial working memory [Camos, V. (2008). Low working memory capacity impedes both efficiency and learning of number transcoding in children. Journal of Experimental Child Psychology, 99(1), 37-57; McLean, J. F., & Hitch, G. J. (1999). Working memory impairments in children with specific arithmetic learning difficulties. Journal of Experimental Child Psychology, 74(3), 240-260; Rosselli, M., Matute, E., Pinto, N., & Ardila, A. (2006). Memory abilities in children with subtypes of dyscalculia. Developmental Neuropsychology, 30(3), 801-818; Siegel, L. S., & Ryan, E. B. (1989). The development of working memory in normally achieving and subtypes of learning disabled children. Child Development, 60(4), 973-980]. The relationship between these two mechanisms is still matter of debate, but this study follows the assumption that poor spatial working memory capacity may hinder the acquisition of spatial number representations in children with DD [Geary, D. C. (1993). Mathematical disabilities: Cognitive, neuropsychological, and genetic components. Psychological Bulletin, 114(2), 345-362; von Aster, M., & Shalev, R. S. (2007). Number development and developmental dyscalculia. Developmental Medicine and Child Neurology, 49(11), 868-873]. Using functional MRI the current study compares brain activity associated with spatial working memory processes in 8-10-year-old children with DD and normally achieving controls
Uresti-Cabrera, Luis A.; Diaz, Rosalinda; Vaca-Palomares, Israel; Fernandez-Ruiz, Juan
Objective. To evaluate the effect of age-related cognitive changes in a visuomotor learning task that depends on strategic control and contrast it with the effect in a task principally depending on visuomotor recalibration. Methods. Participants performed a ball throwing task while donning either a reversing dove prism or a displacement wedge prism, which mainly depend on strategic control or visuomotor recalibration, respectively. Visuomotor performance was then analysed in relation to rule acquisition and reversal, recognition memory, visual memory, spatial planning, and spatial working memory with tasks from the Cambridge Neuropsychological Test Automated Battery (CANTAB). Results. The results confirmed previous works showing a detrimental effect of age on visuomotor learning. The analyses of the cognitive changes observed across age showed that both strategic control and visuomotor recalibration had significant negative correlations only with the number of errors in the spatial working memory task. However, when the effect of aging was controlled, the only significant correlation remaining was between the reversal adaptation magnitude and spatial working memory. Discussion. These results suggest that spatial working memory decline across aging could contribute to age-dependent deterioration in both visuomotor learning processes. However, spatial working memory integrity seems to affect strategic learning decline even after controlling for aging. PMID:26290623
Machado, M L; Lelong-Boulouard, V; Smith, P F; Freret, T; Philoxene, B; Denise, P; Besnard, S
It is now well established that vestibular information plays an important role in spatial memory processes. Although vestibular lesions induce anxiety in humans, this finding remains controversial in rodents. However, it is possible that anxiety-related behavior is associated with spatial memory impairments after vestibular lesions. We aimed to evaluate anxiety-like behavior and the effect of an anxiolytic treatment during a complex spatial memory task in a rat model of compensated bilateral vestibular lesions. Adult rats were divided into four groups, with or without vestibular lesions and, treated or untreated by diazepam. The vestibular lesion was performed by transtympanic injection of arsanilate and compared to transtympanic saline injection. Diazepam or saline was administered 1h before each test or learning session. Vestibular-lesioned rats exhibited anxiety-like behavior which was decreased with diazepam. Spatial memory performance was similar in control-treated and untreated groups, suggesting no effect on memory at the dose of diazepam used. Spatial memory performances were not modified by anxiolytic drug treatment in vestibular-lesioned rats compared to vestibular-lesioned rats without drug treatment. We conclude that bilateral vestibular lesions in rats induced anxiety-like behavior which was unrelated to spatial memory impairment and was probably specifically related to the loss of vestibular information.
Park, D C; Puglisi, J T; Sovacool, M
In the present study the spatial location of picture and word stimuli was varied across four quadrants of photographic slides. Young and old people received either pictures or words to study and were told to remember either just the item or the item and its location. Recognition memory for items and memory for spatial location were tested. A pictorial superiority effect occurred for both old and young people's item recognition. Additionally, instructions to study position decreased item memory and facilitated position memory in both age groups. Spatial memory was markedly superior for pictures compared with matched words for old and young adults. The results are interpreted within the Hasher and Zacks framework of automatic processing. The implications of the data for designing mnemonic aids for elderly persons are considered.
Mammarella, Irene C; Coltri, Silvia; Lucangeli, Daniela; Cornoldi, Cesare
We report the case of B.A., an 11-year-old child with a nonverbal (visuospatial) learning disability (NLD). Detailed psychometric and neuropsychological assessment on visuospatial working memory (VSWM) revealed specific simultaneous-spatial working memory impairment. A treatment targeting simultaneous-spatial working memory was given to B.A. for seven sessions (over one month); this resulted in improvement of simultaneous-spatial working memory, with the benefit that the training was maintained after six months. Discussion of clinical and theoretical implications is given, taking account of the distinctions that can be made between the different components of visuospatial working memory and different subtypes of NLD, thus allowing the tailoring of specific training to target the impaired VSWM component.
Wang, Wei; Tan, Tao; Tu, Man; He, Wenting; Dong, Zhifang; Han, Huili
Reports of the effects of pentobarbital on learning and memory are contradictory. Some studies have not shown any interference with learning and memory, whereas others have shown that pentobarbital impairs memory and that these impairments can last for long periods. However, it is unclear whether acute local microinjections of pentobarbital affect learning and memory, and if so, the potential mechanisms are also unclear. Here, we reported that the intra-hippocampal infusion of pentobarbital (8.0mM, 1μl per side) significantly impaired hippocampus-dependent spatial learning and memory retrieval. Moreover, in vitro electrophysiological recordings revealed that these behavioral changes were accompanied by impaired hippocampal CA1 long-term potentiation (LTP) and suppressed neuronal excitability as reflected by a decrease in the number of action potentials (APs). These results suggest that acute pentobarbital application causes spatial learning and memory deficits that might be attributable to the suppression of synaptic plasticity and neuronal excitability.
Bischof, Hans-Joachim; Lieshoff, Carsten; Watanabe, Shigeru
Spatial memory and hippocampal function have as yet been investigated mainly in pigeons and food storing songbirds. We show here that the zebra finch, a songbird not specialized in food storing and caching, is also able to learn a spatial memory task and uses a spatial map for finding food in a 'dry water maze'. Hippocampal lesions prevent learning and retention of this spatial task. The immediate early gene (IEG) products Zenk and Fos are expressed within the hippocampus when the bird is learning the task. Spatial learning cannot be assigned to any hippocampal subregion; IEG expression within the hippocampus is patchy and seems almost arbitrarily located. The IEG activation pattern in spatial memory experiments is compared with those in other learning experiments with zebra finches.
Glikmann-Johnston, Yifat; Saling, Michael M.; Reutens, David C.; Stout, Julie C.
Spatial cognition is fundamental for survival in the topographically complex environments inhabited by humans and other animals. The hippocampus, which has a central role in spatial cognition, is characterized by high concentration of serotonin (5-hydroxytryptamine; 5-HT) receptor binding sites, particularly of the 1A receptor (5-HT1A) subtype. This review highlights converging evidence for the role of hippocampal 5-HT1A receptors in spatial learning and memory. We consider studies showing that activation or blockade of the 5-HT1A receptors using agonists or antagonists, respectively, lead to changes in spatial learning and memory. For example, pharmacological manipulation to induce 5-HT release, or to block 5-HT uptake, have indicated that increased extracellular 5-HT concentrations maintain or improve memory performance. In contrast, reduced levels of 5-HT have been shown to impair spatial memory. Furthermore, the lack of 5-HT1A receptor subtype in single gene knockout mice is specifically associated with spatial memory impairments. These findings, along with evidence from recent cognitive imaging studies using positron emission tomography (PET) with 5-HT1A receptor ligands, and studies of individual genetic variance in 5-HT1A receptor availability, strongly suggests that 5-HT, mediated by the 5-HT1A receptor subtype, plays a key role in spatial learning and memory. PMID:26696889
Kelly, Jonathan W; McNamara, Timothy P
Previous research has uncovered three primary cues that influence spatial memory organization:egocentric experience, intrinsic structure (object defined), and extrinsic structure (environment defined). In the present experiments, we assessed the relative importance of these cues when all three were available during learning. Participants learned layouts from two perspectives in immersive virtual reality. In Experiment 1, axes defined by intrinsic and extrinsic structures were in conflict, and learning occurred from two perspectives, each aligned with either the intrinsic or the extrinsic structure. Spatial memories were organized around a reference direction selected from the first perspective, regardless of its alignment with intrinsic or extrinsic structures. In Experiment 2, axes defined by intrinsic and extrinsic structures were congruent, and spatial memories were organized around reference axes defined by those congruent structures, rather than by the initially experienced view. The findings are discussed in the context of spatial memory theory as it relates to real and virtual environments.
Bigdeli, Imanollah; Asia, Masomeh Nikfarjam- Haft; Miladi-Gorji, Hossein; Fadaei, Atefeh
Objective(s): There is controversial evidence about the effect of methamphetamine (METH) on spatial memory. We tested the time- dependent effects of METH on spatial short-term (working) and long-term (reference) memory in METH –sensitized and withdrawn rats in the Morris water maze. Materials and Methods: Rats were sensitized to METH (2 mg/kg, daily/5 days, SC). Rats were trained in water maze (4 trials/day/for 5 days). Probe test was performed 24 hr after training. Two days after probe test, working memory training (2 trials/day/for 5 days) was conducted. Acquisition–retention interval was 75 min. The treatment was continued per day 30 and 120 min before the test. Two groups of METH –sensitized rats were trained in reference memory after a longer period of withdrawal (30 days). Results: Sensitized rats exhibited significantly longer escape latencies on the training, spent significantly less time in the target zone (all, P<0.05), and their working memory impaired 30 min after injection. While, METH has no effect on the spatial learning process 120 min after injection, and rats spent significantly less time in the target zone (P<0.05), as well it has no effect on working memory. Also, impairment of reference memory persisted after prolonged abstinence. Conclusion: Our findings indicated that METH impaired spatial learning and memory 30 min after injection, but spared spatial learning, either acquisition or retention of spatial working, but partially impaired retention of spatial reference memory following 120 min after injection in sensitized rats, which persisted even after prolonged abstinence. PMID:25945235
Carr, Joshua K.; Fournier, Neil M.; Lehmann, Hugo
We examined whether increasing retrieval difficulty in a spatial memory task would promote the recruitment of the anterior cingulate cortex (ACC) similar to what is typically observed during remote memory retrieval. Rats were trained on the hidden platform version of the Morris Water Task and tested three or 30 d later. Retrieval difficulty was…
Zhang, Ming; Storm, Daniel R; Wang, Hongbing
When certain memory becomes obsolete, effective suppression of the previously established memory is essential for animals to adapt to the changing environment. At the cellular level, reversal of synaptic potentiation may be important for neurons to acquire new information and to prevent synaptic saturation. Here, we investigated the function of Ca(2+)-stimulated cAMP signaling in the regulation of bidirectional synaptic plasticity and spatial memory formation in double knock-out mice (DKO) lacking both type 1 and 8 adenylyl cyclases (ACs). In anesthetized animals, the DKO mutants showed defective long-term potentiation (LTP) after a single high-frequency stimulation (HFS) or two spaced HFSs at 100 Hz. However, DKO mice showed normal LTP after a single HFS at 200 Hz or two compressed HFSs at 100 Hz. Interestingly, reversal of synaptic potentiation as well as de novo synaptic depression was impaired in DKO mice. In the Morris water maze, DKO mice showed defective acquisition and memory retention, although the deficits could be attenuated by overtraining or compressed trainings with a shorter intertrial interval. In the reversal platform test, DKO animals were impaired in both relearning and old memory suppression. Furthermore, the extinction of the old spatial memory was not efficient in DKO mice. These data demonstrate that Ca(2+)-stimulated AC activity is important not only for LTP and spatial memory formation but also for the suppression of both previously established synaptic potentiation and old spatial memory.
Nadel, Lynn; Uecker, Anne
Thirty Native American children (mean age=10.3 years), 15 identified with fetal alcohol syndrome (FAS) and 15 controls, were asked to recall places and objects in a task previously shown to be sensitive to memory skills in individuals with and without mental retardation. Children with FAS demonstrated a spatial but not an object memory impairment.…
Ekstrom, Arne D.; Bookheimer, Susan Y.
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…
Shelton, Amy L.; Marchette, Steven A.
Testing spatial memory within the same environment used for learning produces interference between one's immediate representation of current position and the to-be-retrieved position. In a series of 3 experiments, we show that "current position" and its influence on memory performance can be driven by conceptual factors in an ambiguous…
Liu, Hu; Wang, Ting; Dai, Wei; Jiang, Zheng; Li, Yuan-hai; Liu, Xue-sheng
Abundant evidence indicates that propofol profoundly affects memory processes, although its specific effects on memory retrieval have not been clarified. A recent study has indicated that hippocampal glycogen synthase kinase-3β (GSK-3β) activity affects memory. Constitutively active GSK-3β is required for memory retrieval, and propofol has been shown to inhibit GSK-3β. Thus, the present study examined whether propofol affects memory retrieval, and, if so, whether that effect is mediated through altered GSK-3β activity. Adult Sprague-Dawley rats were trained on a Morris water maze task (eight acquisition trials in one session) and subjected under the influence of a subhypnotic dose of propofol to a 24-hour probe trial memory retrieval test. The results showed that rats receiving pretest propofol (25 mg/kg) spent significantly less time in the target quadrant but showed no change in locomotor activity compared with those in the control group. Memory retrieval was accompanied by reduced phosphorylation of the serine-9 residue of GSK-3β in the hippocampus, whereas phosphorylation of the tyrosine-216 residue was unaffected. However, propofol blocked this retrieval-associated serine-9 phosphorylation. These findings suggest that subhypnotic propofol administration impairs memory retrieval and that the amnestic effects of propofol may be mediated by attenuated GSK-3β signaling in the hippocampus. PMID:28197192
Liu, Hu; Wang, Ting; Dai, Wei; Jiang, Zheng; Li, Yuan-Hai; Liu, Xue-Sheng
Abundant evidence indicates that propofol profoundly affects memory processes, although its specific effects on memory retrieval have not been clarified. A recent study has indicated that hippocampal glycogen synthase kinase-3β (GSK-3β) activity affects memory. Constitutively active GSK-3β is required for memory retrieval, and propofol has been shown to inhibit GSK-3β. Thus, the present study examined whether propofol affects memory retrieval, and, if so, whether that effect is mediated through altered GSK-3β activity. Adult Sprague-Dawley rats were trained on a Morris water maze task (eight acquisition trials in one session) and subjected under the influence of a subhypnotic dose of propofol to a 24-hour probe trial memory retrieval test. The results showed that rats receiving pretest propofol (25 mg/kg) spent significantly less time in the target quadrant but showed no change in locomotor activity compared with those in the control group. Memory retrieval was accompanied by reduced phosphorylation of the serine-9 residue of GSK-3β in the hippocampus, whereas phosphorylation of the tyrosine-216 residue was unaffected. However, propofol blocked this retrieval-associated serine-9 phosphorylation. These findings suggest that subhypnotic propofol administration impairs memory retrieval and that the amnestic effects of propofol may be mediated by attenuated GSK-3β signaling in the hippocampus.
Talamini, Lucia M; Nieuwenhuis, Ingrid L C; Takashima, Atsuko; Jensen, Ole
The last decade has brought forth convincing evidence for a role of sleep in non-declarative memory. A similar function of sleep in episodic memory is supported by various correlational studies, but direct evidence is limited. Here we show that cued recall of face-location associations is significantly higher following a 12-h retention interval containing sleep than following an equally long period of waking. Furthermore, retention is significantly higher over a 24-h sleep-wake interval than over an equally long wake-sleep interval. This difference occurs because retention during sleep was significantly better when sleep followed learning directly, rather than after a day of waking. These data demonstrate a beneficial effect of sleep on memory that cannot be explained solely as a consequence of reduced interference. Rather, our findings suggest a competitive consolidation process, in which the fate of a memory depends, at least in part, on its relative stability at sleep onset: Strong memories tend to be preserved, while weaker memories erode still further. An important aspect of memory consolidation may thus result from the removal of irrelevant memory "debris."
Morgan, Celia J. A.; Dodds, Chris M.; Furby, Hannah; Pepper, Fiona; Fam, Johnson; Freeman, Tom P.; Hughes, Emer; Doeller, Christian; King, John; Howes, Oliver; Stone, James M.
Ketamine, a non-competitive N-methyl-d-aspartate receptor antagonist, is rising in popularity as a drug of abuse. Preliminary evidence suggests that chronic, heavy ketamine use may have profound effects on spatial memory but the mechanism of these deficits is as yet unclear. This study aimed to examine the neural mechanism by which heavy ketamine use impairs spatial memory processing. In a sample of 11 frequent ketamine users and 15 poly-drug controls, matched for IQ, age, years in education. We used fMRI utilizing an ROI approach to examine the neural activity of three regions known to support successful navigation; the hippocampus, parahippocampal gyrus, and the caudate nucleus during a virtual reality task of spatial memory. Frequent ketamine users displayed spatial memory deficits, accompanied by and related to, reduced activation in both the right hippocampus and left parahippocampal gyrus during navigation from memory, and in the left caudate during memory updating, compared to controls. Ketamine users also exhibited schizotypal and dissociative symptoms that were related to hippocampal activation. Impairments in spatial memory observed in ketamine users are related to changes in medial temporal lobe activation. Disrupted medial temporal lobe function may be a consequence of chronic ketamine abuse and may relate to schizophrenia-like symptomatology observed in ketamine users. PMID:25538631
Méndez-Couz, Marta; Conejo, Nélida M; Vallejo, Guillermo; Arias, Jorge L
Several studies suggest a prefrontal cortex involvement during the acquisition and consolidation of spatial memory, suggesting an active modulating role at late stages of acquisition processes. Recently, we have reported that the prelimbic and infralimbic areas of the prefrontal cortex, among other structures, are also specifically involved in the late phases of spatial memory extinction. This study aimed to evaluate whether the inactivation of the prelimbic area of the prefrontal cortex impaired spatial memory extinction. For this purpose, male Wistar rats were implanted bilaterally with cannulae into the prelimbic region of the prefrontal cortex. Animals were trained during 5 consecutive days in a hidden platform task and tested for reference spatial memory immediately after the last training session. One day after completing the training task, bilateral infusion of the GABAA receptor agonist Muscimol was performed before the extinction protocol was carried out. Additionally, cytochrome c oxidase histochemistry was applied to map the metabolic brain activity related to the spatial memory extinction under prelimbic cortex inactivation. Results show that animals acquired the reference memory task in the water maze, and the extinction task was successfully completed without significant impairment. However, analysis of the functional brain networks involved by cytochrome oxidase activity interregional correlations showed changes in brain networks between the group treated with Muscimol as compared to the saline-treated group, supporting the involvement of the mammillary bodies at a the late stage in the memory extinction process.
Coppola, Vincent J; Hough, Gerald; Bingman, Verner P
The hippocampus is particularly susceptible to age-related degeneration that, like hippocampal lesions, is thought to lead to age-related decline in spatial memory and navigation. Lesions to the avian hippocampal formation (HF) also result in impaired spatial memory and navigation, but the relationship between aging and HF-dependent spatial cognition is unknown. To investigate possible age-related decline in avian spatial cognition, the current study investigated spatial working memory performance in older homing pigeons (10+ years of age). Pigeons completed a behavioral procedure nearly identical to the delayed spatial, win-shift procedure in a modified radial arm maze that has been previously used to study spatial working memory in rats and pigeons. The results revealed that the older pigeons required a greater number of choices to task completion and were less accurate with their first 4 choices as compared to younger pigeons (1-2 years of age). In addition, older pigeons were more likely to adopt a stereotyped sampling strategy, which explained in part their impaired performance. To the best of our knowledge, this study is the first to demonstrate an age-related impairment of HF-dependent, spatial memory in birds. Implications and future directions of the findings are discussed.
Thurm, Franka; Schuck, Nicolas W; Fauser, Mareike; Doeller, Christian F; Stankevich, Yuliya; Evens, Ricarda; Riedel, Oliver; Storch, Alexander; Lueken, Ulrike; Li, Shu-Chen
Striatal dopamine depletion is a key pathophysiological feature of Parkinson's disease (PD) causing motor and nonmotor symptoms. Research on nonmotor symptoms has mainly focused on frontostriatal functions. However, dopamine pathways ascending from the ventral tegmental area also innervate hippocampal structures and modulate hippocampal-dependent functions, such as spatial memory. Using a virtual spatial navigation task, we investigated dopaminergic modulation of spatial memory in PD patients in a crossover medication ON/OFF design. We examined medication effects on striatal- and hippocampal-dependent spatial memory by either replacing a location cue in the environment or enlarging its spatial boundary. Key results indicate that in contrast to prior evidence for younger adults, PD patients, like their age-matched controls, rely more on striatal cue-based than hippocampal spatial learning. Medication facilitated striatal-dependent cue-location learning, whereas medication benefit in hippocampal boundary-related spatial memory depended on prior experience with the task. Medication effects on spatial memory were comparable to and independent of benefits on motor symptoms. These findings shed new light on dopaminergic modulation of hippocampal-striatal functions in PD.
Ludvig, Nandor; Tang, Hai M; Baptiste, Shirn L; Stefanov, Dimitre G; Kral, John G
This study investigated the possible influence of the Subdural Pharmacotherapy Device (SPD) on spatial memory in 3 adult, male bonnet macaques (Macaca radiata). The device was implanted in and above the subdural/subarachnoid space and cranium overlaying the right parietal/frontal cortex: a circuitry involved in spatial memory processing. A large test chamber, equipped with four baited and four non-baited food-ports at different locations, was used: reaches into empty food ports were counted as spatial memory errors. In this study of within-subject design, before SPD implantation (control) the animals made mean 373.3 ± 114.9 (mean ± SEM) errors in the first spatial memory test session. This value dropped to 47.7 ± 18.4 by the 8th session. After SPD implantation and alternating cycles of transmeningeal saline delivery and local cerebrospinal fluid (CSF) drainage in the implanted cortex the spatial memory error count, with the same port locations, was 33.0 ± 12.2 during the first spatial memory test session, further decreasing to 5.7 ± 3.5 by the 8th post-implantation session (P<0.001 for trend). Replacing transmeningeal saline delivery with similar delivery of the GABAA receptor agonist muscimol (1.0mM) by the SPD did not affect the animals' spatial memory performance, which in fact included at least one completely error-free session per animal over time. The study showed that complication-free implantation and use of the SPD over the parietal and frontal cortices for months leave spatial memory processes intact in nonhuman primates.
Viosca, Jose; Malleret, Gaël; Bourtchouladze, Rusiko; Benito, Eva; Vronskava, Svetlana; Kandel, Eric R; Barco, Angel
The activation of cAMP-responsive element-binding protein (CREB)-dependent gene expression is thought to be critical for the formation of different types of long-term memory. To explore the consequences of chronic enhancement of CREB function on spatial memory in mammals, we examined spatial navigation in bitransgenic mice that express in a regulated and restricted manner a constitutively active form of CREB, VP16-CREB, in forebrain neurons. We found that chronic enhancement of CREB activity delayed the acquisition of an allocentric strategy to solve the hidden platform task. The ability to turn on and off transgene expression allowed us to dissect the role of CREB in dissociable memory processes. In mice in which transgene expression was turned on during memory acquisition, turning off the transgene re-established the access to the memory trace, whereas in mice in which transgene expression was turned off during acquisition, turning on the transgene impaired memory expression in a reversible manner, indicating that CREB enhancement specifically interfered with the retrieval of spatial information. The defects on spatial navigation in mice with chronic enhancement of CREB function were not corrected by conditions that increased further CREB-dependent activation of hippocampal memory systems, such as housing in an enriched environment. These results along with previous findings in CREB-deficient mutants indicate that the relationship of CREB-mediated plasticity to spatial memory is an inverted-U function, and that optimal learning in the water maze requires accurate regulation of this pathway.
Méndez-Couz, M; Conejo, N M; González-Pardo, H; Arias, J L
The standard model of memory system consolidation supports the temporal reorganization of brain circuits underlying long-term memory storage, including interactions between the dorsal hippocampus and extra-hippocampal structures. In addition, several brain regions have been suggested to be involved in the retrieval of spatial memory. In particular, several authors reported a possible role of the ventral portion of the hippocampus together with the thalamus or the striatum in the persistence of this type of memory. Accordingly, the present study aimed to evaluate the contribution of different cortical and subcortical brain regions, and neural networks involved in spatial memory retrieval. For this purpose, we used cytochrome c oxidase quantitative histochemistry as a reliable method to measure brain oxidative metabolism. Animals were trained in a hidden platform task and tested for memory retention immediately after the last training session; one week after completing the task, they were also tested in a memory retrieval probe. Results showed that retrieval of the previously learned task was associated with increased levels of oxidative metabolism in the prefrontal cortex, the dorsal and ventral striatum, the anterodorsal thalamic nucleus and the dentate gyrus of the dorsal and ventral hippocampus. The analysis of functional interactions between brain regions suggest that the dorsal and ventral dentate gyrus could be involved in spatial memory retrieval. In addition, the results highlight the key role of the extended hippocampal system, thalamus and striatum in this process. Our study agrees with previous ones reporting interactions between the dorsal hippocampus and the prefrontal cortex during spatial memory retrieval. Furthermore, novel activation patterns of brain networks involving the aforementioned regions were found. These functional brain networks could underlie spatial memory retrieval evaluated in the Morris water maze task.
McEvoy, L K; Smith, M E; Gevins, A
Working memory (WM), the ability to briefly retain and manipulate information in mind, is central to intelligent behavior. Here we take advantage of the high temporal resolution of electrophysiological measures to obtain a millisecond timescale view of the activity induced in distributed cortical networks by tasks that impose significant WM demands. We examined how these networks are affected by the type and amount of information to be remembered, and by the amount of task practice. Evoked potentials (EPs) were obtained from eight subjects performing spatial and verbal versions of a visual n-back WM task (n = 1, 2, 3) on each of three testing days. In well-trained subjects, WM tasks elicited transient responses reflecting different subcomponents of task processing, including transient (lasting 0.02-0.3 s) task-sensitive and load-sensitive EPs, as well as sustained responses (lasting 1-1.5 s), including the prestimulus Contingent Negative Variation (CNV), and post-stimulus frontal and parietal Slow Waves. The transient responses, with the exception of the P300, differed between the verbal and spatial task versions, and between trials with different response requirements. The P300 and the Slow Waves were not affected by task version but were affected by increased WM load. These results suggest that WM emerges from the formation of a dynamic cortical network linking task-specific processes with non-specific, capacity-limited, higher-order attentional processes. Practice effects on the EPs suggested that practice led to the development of a more effective cognitive strategy for dealing with lower-order aspects of task processing, but did not diminish demands made on higher order processes. Thus a simple WM task is shown to be composed of numerous elementary subsecond neural processes whose characteristics vary with type and amount of information being remembered, and amount of practice.
Sawangjit, Anuck; Kelemen, Eduard; Born, Jan; Inostroza, Marion
Social memory refers to the fundamental ability of social species to recognize their conspecifics in quite different contexts. Sleep has been shown to benefit consolidation, especially of hippocampus-dependent episodic memory whereas effects of sleep on social memory are less well studied. Here, we examined the effect of sleep on memory for conspecifics in rats. To discriminate interactions between the consolidation of social memory and of spatial context during sleep, adult Long Evans rats performed on a social discrimination task in a radial arm maze. The Learning phase comprised three 10-min sampling sessions in which the rats explored a juvenile rat presented at a different arm of the maze in each session. Then the rats were allowed to sleep (n = 18) or stayed awake (n = 18) for 120 min. During the following 10-min Test phase, the familiar juvenile rat (of the Learning phase) was presented along with a novel juvenile rat, each rat at an opposite arm of the maze. Significant social recognition memory, as indicated by preferential exploration of the novel over the familiar conspecific, occurred only after post-learning sleep, but not after wakefulness. Sleep, compared with wakefulness, significantly enhanced social recognition during the first minute of the Test phase. However, memory expression depended on the spatial configuration: Significant social recognition memory emerged only after sleep when the rat encountered the novel conspecific at a place different from that of the familiar juvenile in the last sampling session before sleep. Though unspecific retrieval-related effects cannot entirely be excluded, our findings suggest that sleep, rather than independently enhancing social and spatial aspects of memory, consolidates social memory by acting on an episodic representation that binds the memory of the conspecific together with the spatial context in which it was recently encountered.
Sawangjit, Anuck; Kelemen, Eduard; Born, Jan; Inostroza, Marion
Social memory refers to the fundamental ability of social species to recognize their conspecifics in quite different contexts. Sleep has been shown to benefit consolidation, especially of hippocampus-dependent episodic memory whereas effects of sleep on social memory are less well studied. Here, we examined the effect of sleep on memory for conspecifics in rats. To discriminate interactions between the consolidation of social memory and of spatial context during sleep, adult Long Evans rats performed on a social discrimination task in a radial arm maze. The Learning phase comprised three 10-min sampling sessions in which the rats explored a juvenile rat presented at a different arm of the maze in each session. Then the rats were allowed to sleep (n = 18) or stayed awake (n = 18) for 120 min. During the following 10-min Test phase, the familiar juvenile rat (of the Learning phase) was presented along with a novel juvenile rat, each rat at an opposite arm of the maze. Significant social recognition memory, as indicated by preferential exploration of the novel over the familiar conspecific, occurred only after post-learning sleep, but not after wakefulness. Sleep, compared with wakefulness, significantly enhanced social recognition during the first minute of the Test phase. However, memory expression depended on the spatial configuration: Significant social recognition memory emerged only after sleep when the rat encountered the novel conspecific at a place different from that of the familiar juvenile in the last sampling session before sleep. Though unspecific retrieval-related effects cannot entirely be excluded, our findings suggest that sleep, rather than independently enhancing social and spatial aspects of memory, consolidates social memory by acting on an episodic representation that binds the memory of the conspecific together with the spatial context in which it was recently encountered. PMID:28270755
Voyer, Daniel; Voyer, Susan D; Saint-Aubin, Jean
Visual-spatial working memory measures are widely used in clinical and experimental settings. Furthermore, it has been argued that the male advantage in spatial abilities can be explained by a sex difference in visual-spatial working memory. Therefore, sex differences in visual-spatial working memory have important implication for research, theory, and practice, but they have yet to be quantified. The present meta-analysis quantified the magnitude of sex differences in visual-spatial working memory and examined variables that might moderate them. The analysis used a set of 180 effect sizes from healthy males and females drawn from 98 samples ranging in mean age from 3 to 86 years. Multilevel meta-analysis was used on the overall data set to account for non-independent effect sizes. The data also were analyzed in separate task subgroups by means of multilevel and mixed-effects models. Results showed a small but significant male advantage (mean d = 0.155, 95 % confidence interval = 0.087-0.223). All the tasks produced a male advantage, except for memory for location, where a female advantage emerged. Age of the participants was a significant moderator, indicating that sex differences in visual-spatial working memory appeared first in the 13-17 years age group. Removing memory for location tasks from the sample affected the pattern of significant moderators. The present results indicate a male advantage in visual-spatial working memory, although age and specific task modulate the magnitude and direction of the effects. Implications for clinical applications, cognitive model building, and experimental research are discussed.
Foster, Thomas C.; DeFazio, R. A.; Bizon, Jennifer L.
Episodic memory, especially memory for contextual or spatial information, is particularly vulnerable to age-related decline in humans and animal models of aging. The continuing improvement of virtual environment technology for testing humans signifies that widely used procedures employed in the animal literature for examining spatial memory could be developed for examining age-related cognitive decline in humans. The current review examines cross species considerations for implementing these tasks and translating findings across different levels of analysis. The specificity of brain systems as well as gaps in linking human and animal laboratory models is discussed. PMID:22988436
Lee, Choong-Hee; Ryu, Jungwon; Lee, Sang-Hun; Kim, Hakjin; Lee, Inah
The hippocampus plays critical roles in both object-based event memory and spatial navigation, but it is largely unknown whether the left and right hippocampi play functionally equivalent roles in these cognitive domains. To examine the hemispheric symmetry of human hippocampal functions, we used an fMRI scanner to measure BOLD activity while subjects performed tasks requiring both object-based event memory and spatial navigation in a virtual environment. Specifically, the subjects were required to form object-place paired associate memory after visiting four buildings containing discrete objects in a virtual plus maze. The four buildings were visually identical, and the subjects used distal visual cues (i.e., scenes) to differentiate the buildings. During testing, the subjects were required to identify one of the buildings when cued with a previously associated object, and when shifted to a random place, the subject was expected to navigate to the previously chosen building. We observed that the BOLD activity foci changed from the left hippocampus to the right hippocampus as task demand changed from identifying a previously seen object (object-cueing period) to searching for its paired-associate place (object-cued place recognition period). Furthermore, the efficient retrieval of object-place paired associate memory (object-cued place recognition period) was correlated with the BOLD response of the left hippocampus, whereas the efficient retrieval of relatively pure spatial memory (spatial memory period) was correlated with the right hippocampal BOLD response. These findings suggest that the left and right hippocampi in humans might process qualitatively different information for remembering episodic events in space. © 2016 The Authors Hippocampus Published by Wiley Periodicals, Inc.
Lee, Choong‐Hee; Ryu, Jungwon; Lee, Sang‐Hun; Kim, Hakjin
ABSTRACT The hippocampus plays critical roles in both object‐based event memory and spatial navigation, but it is largely unknown whether the left and right hippocampi play functionally equivalent roles in these cognitive domains. To examine the hemispheric symmetry of human hippocampal functions, we used an fMRI scanner to measure BOLD activity while subjects performed tasks requiring both object‐based event memory and spatial navigation in a virtual environment. Specifically, the subjects were required to form object‐place paired associate memory after visiting four buildings containing discrete objects in a virtual plus maze. The four buildings were visually identical, and the subjects used distal visual cues (i.e., scenes) to differentiate the buildings. During testing, the subjects were required to identify one of the buildings when cued with a previously associated object, and when shifted to a random place, the subject was expected to navigate to the previously chosen building. We observed that the BOLD activity foci changed from the left hippocampus to the right hippocampus as task demand changed from identifying a previously seen object (object‐cueing period) to searching for its paired‐associate place (object‐cued place recognition period). Furthermore, the efficient retrieval of object‐place paired associate memory (object‐cued place recognition period) was correlated with the BOLD response of the left hippocampus, whereas the efficient retrieval of relatively pure spatial memory (spatial memory period) was correlated with the right hippocampal BOLD response. These findings suggest that the left and right hippocampi in humans might process qualitatively different information for remembering episodic events in space. © 2016 The Authors Hippocampus Published by Wiley Periodicals, Inc. PMID:27009679
Van de Weijer-Bergsma, Eva; Kroesbergen, Evelyn H; Van Luit, Johannes E H
The relative importance of visual-spatial and verbal working memory for mathematics performance and learning seems to vary with age, the novelty of the material, and the specific math domain that is investigated. In this study, the relations between verbal and visual-spatial working memory and performance in four math domains (i.e., addition, subtraction, multiplication, and division) at different ages during primary school are investigated. Children (N = 4337) from grades 2 through 6 participated. Visual-spatial and verbal working memory were assessed using online computerized tasks. Math performance was assessed at the start, middle, and end of the school year using a speeded arithmetic test. Multilevel Multigroup Latent Growth Modeling was used to model individual differences in level and growth in math performance, and examine the predictive value of working memory per grade, while controlling for effects of classroom membership. The results showed that as grade level progressed, the predictive value of visual-spatial working memory for individual differences in level of mathematics performance waned, while the predictive value of verbal working memory increased. Working memory did not predict individual differences between children in their rate of performance growth throughout the school year. These findings are discussed in relation to three, not mutually exclusive, explanations for such age-related findings.
Working memory capacity increases throughout childhood and adolescence, which is important for the development of a wide range of cognitive abilities, including complex reasoning. The spatial-span task, in which subjects retain information about the order and position of a number of objects, is a sensitive task to measure development of spatial working memory. This review considers results from previous neuroimaging studies investigating the neural correlates of this development. Older children and adolescents, with higher capacity, have been found to have higher brain activity in the intraparietal cortex and in the posterior part of the superior frontal sulcus, during the performance of working memory tasks. The structural maturation of white matter has been investigated by diffusion tensor magnetic resonance imaging (DTI). This has revealed several regions in the frontal lobes in which white matter maturation is correlated with the development of working memory. Among these is a superior fronto-parietal white matter region, located close to the grey matter regions that are implicated in the development of working memory. Furthermore, the degree of white matter maturation is positively correlated with the degree of cortical activation in the frontal and parietal regions. This suggests that during childhood and adolescence, there is development of networks related to specific cognitive functions, such as visuo-spatial working memory. These networks not only consist of cortical areas but also the white matter tracts connecting them. For visuo-spatial working memory, this network could consist of the superior frontal and intraparietal cortex.
Scriba, M F; Gasparini, J; Jacquin, L; Mettke-Hofmann, C; Rattenborg, N C; Roulin, A
Poor environmental conditions experienced during early development can have negative long-term consequences on fitness. Animals can compensate for negative developmental effects through phenotypic plasticity by diverting resources from non-vital to vital traits such as spatial memory to enhance foraging efficiency. We tested in young feral pigeons (Columba livia) how diets of different nutritional value during development affect the capacity to retrieve food hidden in a spatially complex environment, a process we refer to as 'spatial memory'. Parents were fed with either high- or low-quality food from egg laying until young fledged, after which all young pigeons received the same high-quality diet until memory performance was tested at 6 months of age. The pigeons were trained to learn a food location out of 18 possible locations in one session, and then their memory of this location was tested 24 h later. Birds reared with the low-quality diet made fewer errors in the memory test. These results demonstrate that food quality during development has long-lasting effects on memory, with a moderate nutritional deficit improving spatial memory performance in a foraging context. It might be that under poor feeding conditions resources are redirected from non-vital to vital traits, or pigeons raised with low-quality food might be better in using environmental cues such as the position of the sun to find where food was hidden.
Lee, Ogyoung; Redford, Melissa A.
The goal of the present study was to test the effects of working memory on speech production. Twenty American-English speaking adults produced syntactically complex sentences in tasks that taxed either verbal or spatial working memory. Sentences spoken under load were produced with more errors, fewer prosodic breaks, and at faster rates than sentence produced in the control conditions, but other acoustic correlates of rhythm and intonation did not change. Verbal and spatial working memory had very similar effects on production, suggesting that the different span tasks used to tax working memory merely shifted speakers’ attention away from the act of speaking. This finding runs contra the hypothesis of incremental phonological/phonetic encoding, which predicts the manipulation of information in verbal working memory during speech production. PMID:26448563
Kaufman, Miron; Allen, Philip
The molar neural network model of P. Allen, M. Kaufman, A. F. Smith, R. E. Popper, Psychology and Aging 13, 501 (1998) and Experimental Aging Research, 24, 307 (1998) is extended to incorporate reaction times. In our model the entropy associated with a particular task determines the reaction time. We use this molar neural model to directly analyze experimental data on episodic (spatial) memory and semantic (lexical) memory tasks. In particular we are interested in the effect of aging on the two types of memory. We find that there is no difference in performance levels for lexical memory tasks between younger and older adults. In the case spatial memory tasks we find that aging has a detrimental effect on the performance level. This work is supported by NIH/NIA grant AG09282-06.
Saab, Bechara J; Georgiou, John; Nath, Arup; Lee, Frank J S; Wang, Min; Michalon, Aubin; Liu, Fang; Mansuy, Isabelle M; Roder, John C
The molecular underpinnings of exploration and its link to learning and memory remain poorly understood. Here we show that inducible, modest overexpression of neuronal calcium sensor 1 (Ncs1) selectively in the adult murine dentate gyrus (DG) promotes a specific form of exploratory behavior. The mice also display a selective facilitation of long-term potentiation (LTP) in the medial perforant path and a selective enhancement in rapid-acquisition spatial memory, phenotypes that are reversed by direct application of a cell-permeant peptide (DNIP) designed to interfere with NCS-1 binding to the dopamine type-2 receptor (D2R). Moreover, the DNIP and the D2R-selective antagonist L-741,626 attenuated exploratory behavior, DG LTP, and spatial memory in control mice. These data demonstrate a role for NCS-1 and D2R in DG plasticity and provide insight for understanding how the DG contributes to the origin of exploration and spatial memory acquisition.
Perfilova, V N; Zhakupova, G A; Lashchenova, L I; Lebedeva, S A; Tyurenkov, I N
Spatial memory was studied in 2-month-old offspring of rats subjected to different types of experimental preeclampsia (replacement of drinking water with 1.8% NaCl from day 1 to 21 of gestation or intraperitoneal administration of non-selective NO-synthase inhibitor L-NAME to pregnant rats in a daily dose of 25 mg/kg for 7 days on gestation days 14-20). Spatial memory was evaluated in an elevated 8-arm radial maze. Both types of experimental preeclampsia impaired spatial (long-term and short-term) memory and can be used in the development of drugs correcting negative effects of this pregnancy complication on memory.
Mammarella, Irene Cristina; Lucangeli, Daniela; Cornoldi, Cesare
Visuospatial working memory and its involvement in arithmetic were examined in two groups of 7- to 11-year-olds: one comprising children described by teachers as displaying symptoms of nonverbal learning difficulties (N = 21), the other a control group without learning disabilities (N = 21). The two groups were matched for verbal abilities, age, gender, and sociocultural level. The children were presented with a visuospatial working memory battery of recognition tests involving visual, spatial-sequential and spatial-simultaneous processes, and two arithmetic tasks (number ordering and written calculations). The two groups were found to differ on some spatial tasks but not in the visual working memory tasks. On the arithmetic tasks, the children with nonverbal learning difficulties made more errors than controls in calculation and were slower in number ordering. A discriminant function analysis confirmed the crucial role of spatial-sequential working memory in distinguishing between the two groups. Results are discussed with reference to spatial working memory and arithmetic difficulties in nonverbal learning disabilities. Implications for the relationship between visuospatial working memory and arithmetic are also considered.
Allan, K; Allan, J L
To help maintain a positive energy balance in ancestral human habitats, evolution appears to have designed a functional bias in spatial memory that enhances our ability to remember the location of high-calorie foodstuffs. Here, we investigated whether this functional bias has obesogenic consequences for individuals living in a modern urban environment. Spatial memory, dietary intentions, and perceived desirability, for high-calorie snacks and lower-calorie fruits and vegetables were measured using a computer-based task in 41 women (age: 18-35, body mass index: 18.5-30.0). Using multiple linear regression, we analyzed whether enhanced spatial memory for high-calorie snacks versus fruits and vegetables predicted BMI, controlling for dietary intention strength and perceived food desirability. We observed that enhanced spatial memory for high-calorie snacks (both independently, and relative to that for fruits and vegetables), significantly predicted higher BMI. The evolved function of high-calorie bias in human spatial memory, to promote positive energy balance, would therefore appear to be intact. But our data reveal that this function may contribute to higher, less healthy BMI in individuals in whom the memory bias is most marked. Our findings reveal a novel cognitive marker of vulnerability to weight gain that, once the proximal mechanisms are understood, may offer new possibilities for weight control interventions.
Rensel, Michelle A; Ellis, Jesse M S; Harvey, Brigit; Schlinger, Barney A
Estrogens significantly impact spatial memory function in mammalian species. Songbirds express the estrogen synthetic enzyme aromatase at relatively high levels in the hippocampus and there is evidence from zebra finches that estrogens facilitate performance on spatial learning and/or memory tasks. It is unknown, however, whether estrogens influence hippocampal function in songbirds that naturally exhibit memory-intensive behaviors, such as cache recovery observed in many corvid species. To address this question, we examined the impact of estradiol on spatial memory in non-breeding Western scrub-jays, a species that routinely participates in food caching and retrieval in nature and in captivity. We also asked if there were sex differences in performance or responses to estradiol. Utilizing a combination of an aromatase inhibitor, fadrozole, with estradiol implants, we found that while overall cache recovery rates were unaffected by estradiol, several other indices of spatial memory, including searching efficiency and efficiency to retrieve the first item, were impaired in the presence of estradiol. In addition, males and females differed in some performance measures, although these differences appeared to be a consequence of the nature of the task as neither sex consistently out-performed the other. Overall, our data suggest that a sustained estradiol elevation in a food-caching bird impairs some, but not all, aspects of spatial memory on an innate behavioral task, at times in a sex-specific manner.
Wareing, Michelle; Fisk, John E; Murphy, Philip; Montgomery, Catharine
Verbal working memory and executive deficits have been observed in ecstasy users. The present study sought to establish whether these also extended to visuo-spatial working memory. Thirty-six current ecstasy users, 12 former users (abstinent for at least 6 months) and 31 individuals that had never used ecstasy were tested on a maintenance plus type visuo-spatial working memory task. The task required participants to recall a sequence of specially marked cells in a four-by-four matrix display while at the same time performing a concurrent visual judgement task. Both the current and former user groups registered impairments relative to nonusers. These remained significant following statistical controls for a range of potentially confounding variables including the use of various other drugs during the 3 months prior to testing. Users were unimpaired on a simple spatial span measure suggesting that the deficits observed reflected the executive aspects of the spatial working memory task. Also consistent with executive involvement, statistical controls for measures of verbal working memory performance (computation span) removed half of the ecstasy-related variance in spatial working memory. The possibility that the pattern of results obtained might reflect some general impairment in information processing efficiency is discussed.
Pooters, Tine; Van der Jeugd, Ann; Callaerts-Vegh, Zsuzsanna; D'Hooge, Rudi
Spatial learning and memory in rodents represent close equivalents of human episodic declarative memory, which is especially sensitive to cerebral aging, neurodegeneration, and various neuropsychiatric disorders. Many tests and protocols are available for use in laboratory rodents, but Morris water maze and radial-arm maze remain the most widely used as well as the most valid and reliable spatial tests. Telencephalic neurocircuitry that plays functional roles in spatial learning and memory includes hippocampus, dorsal striatum and medial prefrontal cortex. Prefrontal-hippocampal circuitry comprises the major associative system in the rodent brain, and is critical for navigation in physical space, whereas interconnections between prefrontal cortex and dorsal striatum are probably more important for motivational or goal-directed aspects of spatial learning. Two major forms of synaptic plasticity, namely long-term potentiation, a lasting increase in synaptic strength between simultaneously activated neurons, and long-term depression, a decrease in synaptic strength, have been found to occur in hippocampus, dorsal striatum and medial prefrontal cortex. These and other phenomena of synaptic plasticity are probably crucial for the involvement of telencephalic neurocircuitry in spatial learning and memory. They also seem to play a role in the pathophysiology of two brain pathologies with episodic declarative memory impairments as core symptoms, namely Alzheimer's disease and schizophrenia. Further research emphasis on rodent telencephalic neurocircuitry could be relevant to more valid and reliable preclinical research on these most devastating brain disorders. This article is part of a Special Issue entitled SI: Brain and Memory.
Jang, Saebyeol; Dilger, Ryan N.; Johnson, Rodney W.
A dysregulated overexpression of inflammatory mediators by microglia may facilitate cognitive aging and neurodegeneration. Considerable evidence suggests the flavonoid luteolin has antiinflammatory effects, but its ability to inhibit microglia, reduce inflammatory mediators, and improve hippocampal-dependent learning and memory in aged mice is unknown. In initial studies, pretreatment of BV-2 microglia with luteolin inhibited the induction of inflammatory genes and the release of inflammatory mediators after lipopolysaccharide (LPS) stimulation. Supernatants from LPS-stimulated microglia caused discernible death in Neuro.2a cells. However, treating microglia with luteolin prior to LPS reduced neuronal cell death caused by conditioned supernatants, indicating luteolin was neuroprotective. In subsequent studies, adult (3–6 mo) and aged (22–24 mo) mice were fed control or luteolin (20 mg/d)-supplemented diet for 4 wk and spatial working memory was assessed as were several inflammatory markers in the hippocampus. Aged mice fed control diet exhibited deficits in spatial working memory and expression of inflammatory markers in the hippocampus indicative of increased microglial cell activity. Luteolin consumption improved spatial working memory and restored expression of inflammatory markers in the hippocampus compared with that of young adults. Luteolin did not affect either spatial working memory or inflammatory markers in young adults. Taken together, the current findings suggest dietary luteolin enhanced spatial working memory by mitigating microglial-associated inflammation in the hippocampus. Therefore, luteolin consumption may be beneficial in preventing or treating conditions involving increased microglial cell activity and inflammation. PMID:20685893
Fremouw, Thane; Fessler, Christy L; Ferguson, Robert J; Burguete, Yamil
Clinical studies suggest that chemotherapy is associated with long-term cognitive impairment in some patients. A number of underlying mechanisms have been proposed, however, the etiology of chemotherapy-related cognitive dysfunction remains relatively unknown. As part of a multifaceted approach, animal models of chemotherapy-induced cognitive impairment are being developed. Thus far, the majority of animal studies have utilized a rat model, however, mice may prove particularly beneficial in studying genetic risk factors for developing chemotherapy-induced cognitive impairment. Various chemotherapy agents, including cytosine arabinoside (Ara-C), have been found to impair remote spatial memory in rats in the Morris water maze. The present study evaluated the effects of Ara-C on remote (30 d) spatial memory in mice. In addition, the possibility that time relative to chemotherapy treatment may modulate the effect of chemotherapy on spatial learning and/or recent (1 d) memory was explored. Male C57BL/6J mice received either Ara-C (275 mg/kg i.p. daily for 5 days) or saline. Spatial learning and memory was assessed using the Morris water maze. Half the mice performed a remote (30 d) memory version of the task and the other half performed a recent (1 d) memory version of the task. The experiment was designed such that the probe trial for the recent memory version occurred on the same day relative to chemotherapy treatment as the remote memory version. Despite significant toxic effects as assessed by weight loss, Ara-C treated mice performed as well as control mice during acquisition, recent memory, and remote memory portions of the task. As are some humans, C57BL/6J mice may be resistant to at least some aspects of chemotherapy induced cognitive decline.
Murray, Andrew J; Sauer, Jonas-Frederic; Riedel, Gernot; McClure, Christina; Ansel, Laura; Cheyne, Lesley; Bartos, Marlene; Wisden, William; Wulff, Peer
Parvalbumin-positive GABAergic interneurons in cortical circuits are hypothesized to control cognitive function. To test this idea directly, we functionally removed parvalbumin-positive interneurons selectively from hippocampal CA1 in mice. We found that parvalbumin-positive interneurons are dispensable for spatial reference, but are essential for spatial working memory.
Rahman, Qazi; Newland, Cherie; Smyth, Beatrice Mary
Prior research has demonstrated robust sex and sexual orientation-related differences in object location memory in humans. Here we show that this sexual variation may depend on the spatial position of target objects and the task-specific nature of the spatial array. We tested the recovery of object locations in three object arrays (object…
Park, Denise Cortis; And Others
Tested recognition memory for items and spatial location by varying picture and word stimuli across four slide quadrants. Results showed a pictorial superiority effect for item recognition and a greater ability to remember the spatial location of pictures versus words for both old and young adults (N=95). (WAS)
Guerard, Katherine; Tremblay, Sebastien
The authors revisited evidence in favor of modularity and of functional equivalence between the processing of verbal and spatial information in short-term memory. This was done by investigating the patterns of intrusions, omissions, transpositions, and fill-ins in verbal and spatial serial recall and order reconstruction tasks under control,…
Madl, Tamas; Chen, Ke; Montaldi, Daniela; Trappl, Robert
Spatial memory refers to the part of the memory system that encodes, stores, recognizes and recalls spatial information about the environment and the agent's orientation within it. Such information is required to be able to navigate to goal locations, and is vitally important for any embodied agent, or model thereof, for reaching goals in a spatially extended environment. In this paper, a number of computationally implemented cognitive models of spatial memory are reviewed and compared. Three categories of models are considered: symbolic models, neural network models, and models that are part of a systems-level cognitive architecture. Representative models from each category are described and compared in a number of dimensions along which simulation models can differ (level of modeling, types of representation, structural accuracy, generality and abstraction, environment complexity), including their possible mapping to the underlying neural substrate. Neural mappings are rarely explicated in the context of behaviorally validated models, but they could be useful to cognitive modeling research by providing a new approach for investigating a model's plausibility. Finally, suggested experimental neuroscience methods are described for verifying the biological plausibility of computational cognitive models of spatial memory, and open questions for the field of spatial memory modeling are outlined.
Bellani, Rudy; Luecken, Linda J; Conrad, Cheryl D
We tested the hypothesis that peripubertal anxiety levels are predictive of the detrimental effects of chronic stress on hippocampal-dependent spatial memory. The anxiety levels of peripubertal male Sprague-Dawley rats (43 days old) were characterized using open field and elevated plus mazes, followed by chronic restraint stress for 6 h/day/21 days beginning in young adulthood (75 days). Following chronic stress treatment, rats were tested on the spatial Y-maze using two inter-trial interval levels of difficulty (4 h: 1 day post-chronic stress; 1 min: 2 days post-chronic stress). As expected, all groups displayed intact spatial memory in the less difficult 1 min version of the Y-maze. However, in the 4 h version of the Y-maze, chronically stressed high anxiety rats showed impaired spatial memory, while chronically stressed low anxiety and control (low and high anxiety) rats displayed intact spatial memory. Moreover, a month after chronic stress ended, high anxiety rats had significantly higher basal corticosterone levels than low anxiety rats (control and stress). These results indicate that peripubertal anxiety and chronic stress interact to influence hippocampal-dependent spatial memory in adulthood.
Coltman, Robin; Spain, Aisling; Tsenkina, Yanina; Fowler, Jill H; Smith, Jessica; Scullion, Gillian; Allerhand, Mike; Scott, Fiona; Kalaria, Rajesh N; Ihara, Masafumi; Daumas, Stephanie; Deary, Ian J; Wood, Emma; McCulloch, James; Horsburgh, Karen
The integrity of the white matter is critical in regulating efficient neuronal communication and maintaining cognitive function. Damage to brain white matter putatively contributes to age-related cognitive decline. There is a growing interest in animal models from which the mechanistic basis of white matter pathology in aging can be elucidated but to date there has been a lack of systematic behavior and pathology in the same mice. Anatomically widespread, diffuse white matter damage was induced, in 3 different cohorts of C57Bl/6J mice, by chronic hypoperfusion produced by bilateral carotid stenosis. A comprehensive assessment of spatial memory (spatial reference learning and memory; cohort 1) and serial spatial learning and memory (cohort 2) using the water maze, and spatial working memory (cohort 3) using the 8-arm radial arm maze, was conducted. In parallel, a systematic assessment of white matter components (myelin, axon, glia) was conducted using immunohistochemical markers (myelin-associated glycoprotein [MAG], degraded myelin basic protein [dMBP], anti-amyloid precursor protein [APP], anti-ionized calcium-binding adapter molecule [Iba-1]). Ischemic neuronal perikarya damage, assessed using histology (hematoxylin and eosin; H&E), was absent in all shams but was present in some hypoperfused mice (2/11 in cohort 1, 4/14 in cohort 2, and 17/24 in cohort 3). All animals with neuronal perikaryal damage were excluded from further study. Diffuse white matter damage occurred, throughout the brain, in all hypoperfused mice in each cohort and was essentially absent in sham-operated controls. There was a selective impairment in spatial working memory, with all other measures of spatial memory remaining intact, in hypoperfused mice with selective white matter damage. The results demonstrate that diffuse white matter pathology, in the absence of gray matter damage, induces a selective impairment of spatial working memory. This highlights the importance of assessing
Heuer, Eric; Bachevalier, Jocelyne
Earlier studies in monkeys have reported mild impairment in recognition memory following nonselective neonatal hippocampal lesions (Bachevalier, Beauregard, & Alvarado, 1999; Rehbein, Killiany, & Mahut, 2005). To assess whether the memory impairment could have resulted from damage to cortical areas adjacent to the hippocampus, we tested adult monkeys with neonatal focal hippocampal lesions and sham-operated controls in three recognition tasks: delayed nonmatching-to-sample, object memory span, and spatial memory span. Further, to rule out that normal performance on these tasks may relate to functional sparing following neonatal hippocampal lesions, we tested adult monkeys that had received the same focal hippocampal lesions in adulthood and their controls in the same three memory tasks. Both early and late onset focal hippocampal damage did not alter performance on any of the three tasks, suggesting that damage to cortical areas adjacent to the hippocampus was likely responsible for the recognition impairment reported by the earlier studies. In addition, given that animals with early and late onset hippocampal lesions showed object and spatial recognition impairment when tested in a visual paired comparison task (Zeamer, Meunier, & Bachevalier, Submitted; Zeamer, Heuer & Bachevalier, 2010), the data suggest that not all object and spatial recognition tasks are solved by hippocampal-dependent memory processes. The current data may not only help explain the neural substrate for the partial recognition memory impairment reported in cases of developmental amnesia (Adlam, Malloy, Mishkin, & Vargha-Khadem, 2009), but they are also clinically relevant given that the object and spatial memory tasks used in monkeys are often translated to investigate memory functions in several populations of human infants and children in which dysfunction of the hippocampus is suspected. PMID:21341885
Barnhart, Christopher D; Yang, Dongren; Lein, Pamela J
Mouse models have been indispensable for elucidating normal and pathological processes that influence learning and memory. A widely used method for assessing these cognitive processes in mice is the Morris water maze, a classic test for examining spatial learning and memory. However, Morris water maze studies with mice have principally been performed using adult animals, which preclude studies of critical neurodevelopmental periods when the cellular and molecular substrates of learning and memory are formed. While weanling rats have been successfully trained in the Morris water maze, there have been few attempts to test weanling mice in this behavioral paradigm even though mice offer significant experimental advantages because of the availability of many genetically modified strains. Here, we present experimental evidence that weanling mice can be trained in the Morris water maze beginning on postnatal day 24. Maze-trained weanling mice exhibit significant improvements in spatial learning over the training period and results of the probe trial indicate the development of spatial memory. There were no sex differences in the animals' performance in these tasks. In addition, molecular biomarkers of synaptic plasticity are upregulated in maze-trained mice at the transcript level. These findings demonstrate that the Morris water maze can be used to assess spatial learning and memory in weanling mice, providing a potentially powerful experimental approach for examining the influence of genes, environmental factors and their interactions on the development of learning and memory.
Szucs, Denes; Devine, Amy; Soltesz, Fruzsina; Nobes, Alison; Gabriel, Florence
Developmental dyscalculia is thought to be a specific impairment of mathematics ability. Currently dominant cognitive neuroscience theories of developmental dyscalculia suggest that it originates from the impairment of the magnitude representation of the human brain, residing in the intraparietal sulcus, or from impaired connections between number symbols and the magnitude representation. However, behavioral research offers several alternative theories for developmental dyscalculia and neuro-imaging also suggests that impairments in developmental dyscalculia may be linked to disruptions of other functions of the intraparietal sulcus than the magnitude representation. Strikingly, the magnitude representation theory has never been explicitly contrasted with a range of alternatives in a systematic fashion. Here we have filled this gap by directly contrasting five alternative theories (magnitude representation, working memory, inhibition, attention and spatial processing) of developmental dyscalculia in 9-10-year-old primary school children. Participants were selected from a pool of 1004 children and took part in 16 tests and nine experiments. The dominant features of developmental dyscalculia are visuo-spatial working memory, visuo-spatial short-term memory and inhibitory function (interference suppression) impairment. We hypothesize that inhibition impairment is related to the disruption of central executive memory function. Potential problems of visuo-spatial processing and attentional function in developmental dyscalculia probably depend on short-term memory/working memory and inhibition impairments. The magnitude representation theory of developmental dyscalculia was not supported.
Moroni, Fabio; Nobili, Lino; Iaria, Giuseppe; Sartori, Ivana; Marzano, Cristina; Tempesta, Daniela; Proserpio, Paola; Lo Russo, Giorgio; Gozzo, Francesca; Cipolli, Carlo; De Gennaro, Luigi; Ferrara, Michele
The hypothesis that sleep is instrumental in the process of memory consolidation is currently largely accepted. Hippocampal formation is involved in the acquisition of declarative memories and particularly of spatial memories. Nevertheless, although largely investigated in rodents, the relations between spatial memory and hippocampal EEG activity have been scarcely studied in humans. Aimed to evaluate the effects of spatial learning on human hippocampal sleep EEG activity, we recorded hippocampal Stereo-EEG (SEEG) in a group of refractory epilepsy patients undergoing presurgical clinical evaluation, after a training on a spatial navigation task. We observed that hippocampal high-delta (2-4 Hz range) activity increases during the first NREM episode after learning compared to the baseline night. Moreover, the amount of hippocampal NREM high-delta power was correlated with task performance at retest. The effect involved only the hippocampal EEG frequencies inasmuch no differences were observed at the neocortical electrodes and in the traditional polysomnographic measures. The present findings support the crucial role of hippocampal slow EEG frequencies during sleep in the memory consolidation processes. More generally, together with previous results, they suggest that slow frequency rhythms are a fundamental characteristic of human hippocampal EEG during both sleep and wakefulness, and are related to the consolidation of different types of memories.
Kaufman, Scott Barry
Sex differences in spatial ability are well documented, but poorly understood. In order to see whether working memory is an important factor in these differences, 50 males and 50 females performed tests of three-dimensional mental rotation and spatial visualization, along with tests of spatial and verbal working memory. Substantial differences…
Arthur, Joeanna C; Philbeck, John W; Kleene, Nicholas J; Chichka, David
Angular path integration refers to the ability to maintain an estimate of self-location after a rotational displacement by integrating internally-generated (idiothetic) self-motion signals over time. Previous work has found that non-sensory inputs, namely spatial memory, can play a powerful role in angular path integration (Arthur et al., 2007, 2009). Here we investigated the conditions under which spatial memory facilitates angular path integration. We hypothesized that the benefit of spatial memory is particularly likely in spatial updating tasks in which one's self-location estimate is referenced to external space. To test this idea, we administered passive, non-visual body rotations (ranging 40°-140°) about the yaw axis and asked participants to use verbal reports or open-loop manual pointing to indicate the magnitude of the rotation. Prior to some trials, previews of the surrounding environment were given. We found that when participants adopted an egocentric frame of reference, the previously-observed benefit of previews on within-subject response precision was not manifested, regardless of whether remembered spatial frameworks were derived from vision or spatial language. We conclude that the powerful effect of spatial memory is dependent on one's frame of reference during self-motion updating.
While neurons in the lateral prefrontal cortex (PFC) encode spatial information during the performance of working memory tasks, they are also known to participate in subjective behavior such as spatial attention and action selection. In the present study, we analyzed the activity of primate PFC neurons during the performance of a free choice memory-guided saccade task in which the monkeys needed to choose a saccade direction by themselves. In trials when the receptive field location was subsequently chosen by the animal, PFC neurons with spatially selective visual response started to show greater activation before cue onset. This result suggests that the fluctuation of firing before cue presentation prematurely biased the representation of a certain spatial location and eventually encouraged the subsequent choice of that location. In addition, modulation of the activity by the animal's choice was observed only in neurons with high sustainability of activation and was also dependent on the spatial configuration of the visual cues. These findings were consistent with known characteristics of PFC neurons in information maintenance in spatial working memory function. These results suggest that precue fluctuation of spatial representation was shared and enhanced through the working memory network in the PFC and could finally influence the animal's free choice of saccade direction. The present study revealed that the PFC plays an important role in decision making in a free choice condition and that the dynamics of decision making are constrained by the network architecture embedded in this cortical area. PMID:26490287
Mochizuki, Kei; Funahashi, Shintaro
While neurons in the lateral prefrontal cortex (PFC) encode spatial information during the performance of working memory tasks, they are also known to participate in subjective behavior such as spatial attention and action selection. In the present study, we analyzed the activity of primate PFC neurons during the performance of a free choice memory-guided saccade task in which the monkeys needed to choose a saccade direction by themselves. In trials when the receptive field location was subsequently chosen by the animal, PFC neurons with spatially selective visual response started to show greater activation before cue onset. This result suggests that the fluctuation of firing before cue presentation prematurely biased the representation of a certain spatial location and eventually encouraged the subsequent choice of that location. In addition, modulation of the activity by the animal's choice was observed only in neurons with high sustainability of activation and was also dependent on the spatial configuration of the visual cues. These findings were consistent with known characteristics of PFC neurons in information maintenance in spatial working memory function. These results suggest that precue fluctuation of spatial representation was shared and enhanced through the working memory network in the PFC and could finally influence the animal's free choice of saccade direction. The present study revealed that the PFC plays an important role in decision making in a free choice condition and that the dynamics of decision making are constrained by the network architecture embedded in this cortical area.
Guan, Zhiwei; Peng, Xuwen; Fang, Jidong
Loss of sleep may result in memory impairment. However, little is known about the biochemical basis for memory deficits induced by sleep deprivation. Extracellular signal-regulated kinase (ERK) is involved in memory consolidation in different tasks. Phosphorylation of ERK is necessary for its activation and is an important step in mediating neuronal responses to synaptic activities. The aim of the present study was to determine the effects of total sleep deprivation (TSD) on memory and ERK phosphorylation in the brain. Rats were trained in Morris water maze to find a hidden platform (a spatial task) or a visible platform (a nonspatial task) after 6 h TSD or spontaneous sleep. TSD had no effect on spatial learning, but significantly impaired spatial memory tested 24 h after training. Nonspatial learning and memory were not impaired by TSD. Phospho-ERK levels in the hippocampus were significantly reduced after 6 h TSD compared to the controls and returned to the control levels after 2 h recovery sleep. Total ERK1 and ERK2 were slightly increased after 6 h TSD and returned to the control levels after 2 h recovery sleep. These alterations were not observed in the cortex after TSD. Protein phosphotase-1 and mitogen-activated protein kinase phosphatase-2, which dephosphorylates phospho-ERK, were also measured, but they were not altered by TSD. The impairments of both spatial memory and ERK phosphorylation indicate that the hippocampus is vulnerable to sleep loss. These results are consistent with the idea that decreased ERK activation in the hippocampus is involved in sleep deprivation-induced spatial memory impairment.
Juan, M-Carmen; Mendez-Lopez, Magdalena; Perez-Hernandez, Elena; Albiol-Perez, Sergio
Short-term memory can be defined as the capacity for holding a small amount of information in mind in an active state for a short period of time. Although some instruments have been developed to study spatial short-term memory in real environments, there are no instruments that are specifically designed to assess visuospatial short-term memory in an attractive way to children. In this paper, we present the ARSM (Augmented Reality Spatial Memory) task, the first Augmented Reality task that involves a user's movement to assess spatial short-term memory in healthy children. The experimental procedure of the ARSM task was designed to assess the children's skill to retain visuospatial information. They were individually asked to remember the real place where augmented reality objects were located. The children (N = 76) were divided into two groups: preschool (5-6 year olds) and primary school (7-8 year olds). We found a significant improvement in ARSM task performance in the older group. The correlations between scores for the ARSM task and traditional procedures were significant. These traditional procedures were the Dot Matrix subtest for the assessment of visuospatial short-term memory of the computerized AWMA-2 battery and a parent's questionnaire about a child's everyday spatial memory. Hence, we suggest that the ARSM task has high verisimilitude with spatial short-term memory skills in real life. In addition, we evaluated the ARSM task's usability and perceived satisfaction. The study revealed that the younger children were more satisfied with the ARSM task. This novel instrument could be useful in detecting visuospatial short-term difficulties that affect specific developmental navigational disorders and/or school academic achievement.
Juan, M.-Carmen; Mendez-Lopez, Magdalena; Perez-Hernandez, Elena; Albiol-Perez, Sergio
Short-term memory can be defined as the capacity for holding a small amount of information in mind in an active state for a short period of time. Although some instruments have been developed to study spatial short-term memory in real environments, there are no instruments that are specifically designed to assess visuospatial short-term memory in an attractive way to children. In this paper, we present the ARSM (Augmented Reality Spatial Memory) task, the first Augmented Reality task that involves a user's movement to assess spatial short-term memory in healthy children. The experimental procedure of the ARSM task was designed to assess the children's skill to retain visuospatial information. They were individually asked to remember the real place where augmented reality objects were located. The children (N = 76) were divided into two groups: preschool (5–6 year olds) and primary school (7–8 year olds). We found a significant improvement in ARSM task performance in the older group. The correlations between scores for the ARSM task and traditional procedures were significant. These traditional procedures were the Dot Matrix subtest for the assessment of visuospatial short-term memory of the computerized AWMA-2 battery and a parent's questionnaire about a child's everyday spatial memory. Hence, we suggest that the ARSM task has high verisimilitude with spatial short-term memory skills in real life. In addition, we evaluated the ARSM task's usability and perceived satisfaction. The study revealed that the younger children were more satisfied with the ARSM task. This novel instrument could be useful in detecting visuospatial short-term difficulties that affect specific developmental navigational disorders and/or school academic achievement. PMID:25438146
Conrad, Cheryl D
The purpose of this review is to evaluate the effects of chronic stress on hippocampal-dependent function, based primarily upon studies using young, adult male rodents and spatial navigation tasks. Despite this restriction, variability amongst the findings was evident and how or even whether chronic stress influenced spatial ability depended upon the type of task, the dependent variable measured and how the task was implemented, the type and duration of the stressors, housing conditions of the animals that include accessibility to food and cage mates, and duration from the end of the stress to the start of behavioral assessment. Nonetheless, patterns emerged as follows: For spatial memory, chronic stress impairs spatial reference memory and has transient effects on spatial working memory. For spatial learning, however, chronic stress effects appear to be task-specific: chronic stress impairs spatial learning on appetitively motivated tasks, such as the radial arm maze or holeboard, tasks that evoke relatively mild to low arousal components from fear. But under testing conditions that evoke moderate to strong arousal components from fear, such as during radial arm water maze testing, chronic stress appears to have minimal impairing effects or may even facilitate spatial learning. Chronic stress clearly impacts nearly every brain region and thus, how chronic stress alters hippocampal spatial ability likely depends upon the engagement of other brain structures during behavioral training and testing.
Bonnì, Sonia; Perri, Roberta; Fadda, Lucia; Tomaiuolo, Francesco; Koch, Giacomo; Caltagirone, Carlo; Carlesimo, Giovanni Augusto
We report the neuropsychological and MRI investigation of a patient (GP) who developed a selective impairment of spatial short-term memory (STM) following damage to the dorso-mesial areas of the right frontal lobe. We assessed in this patient spatial STM with an experimental procedure that evaluated immediate and 5-20 s delayed recall of verbal, visual and spatial stimuli. The patient scored significantly worse than normal controls on tests that required delayed recall of spatial data. This could not be ascribed to a deficit of spatial episodic long-term memory because amnesic patients performed normally on these tests. Conversely, the patient scored in the normal range on tests of immediate recall of verbal, visual and spatial data and tests of delayed recall of verbal and visual data. Comparison with a previously described patient who had a selective deficit in immediate spatial recall and an ischemic lesion that affected frontal and parietal dorso-mesial areas in the right hemisphere (Carlesimo GA, Perri R, Turriziani P, Tomaiuolo F, Caltagirone C. Remembering what but not where: independence of spatial and visual working memory in the human brain. Cortex. 2001 Sep; 37(4):519-34) suggests that the right parietal areas are involved in the short-term storage of spatial information and that the dorso-mesial regions of the right frontal underlie mechanisms for the delayed maintenance of the same data.
Kobilo, Tali; Yuan, Chunyan; van Praag, Henriette
Physical activity improves learning and hippocampal neurogenesis. It is unknown whether compounds that increase endurance in muscle also enhance cognition. We investigated the effects of endurance factors, peroxisome proliferator-activated receptor [delta] agonist GW501516 and AICAR, activator of AMP-activated protein kinase on memory and…
Solman, Grayden J F; Kingstone, Alan
Humans are remarkably capable of finding desired objects in the world, despite the scale and complexity of naturalistic environments. Broadly, this ability is supported by an interplay between exploratory search and guidance from episodic memory for previously observed target locations. Here we examined how the environment itself may influence this interplay. In particular, we examined how partitions in the environment-like buildings, rooms, and furniture-can impact memory during repeated search. We report that the presence of partitions in a display, independent of item configuration, reliably improves episodic memory for item locations. Repeated search through partitioned displays was faster overall and was characterized by more rapid ballistic orienting in later repetitions. Explicit recall was also both faster and more accurate when displays were partitioned. Finally, we found that search paths were more regular and systematic when displays were partitioned. Given the ubiquity of partitions in real-world environments, these results provide important insights into the mechanisms of naturalistic search and its relation to memory.
Chen, Di; Liu, Fang; Wan, Jian-Bo; Lai, Chao-Qiang; Shen, Li-Rong
Royal jelly (RJ) produced by worker honeybees is the sole food for the queen bee throughout her life as well as the larvae of worker bees for the first 3 days after hatching. Supplementation of RJ in the diet has been shown to increase spatial memory in rodents. However, the key constituents in RJ responsible for improvement of cognitive function are unknown. Our objective was to determine if the major royal jelly proteins (MRJPs) extracted from RJ can improve the spatial memory of aged rats. The spatial memory assay using the Morris water maze test was administered once to rats after a 14-week feeding. Metabolomics analysis based on quadrupole time-of-flight mass spectrometry was conducted to examine the differences in compounds from urine. Aged male rats fed MRJPs showed improved spatial memory up to 48.5% when compared to the control male aged rats fed distilled water. The metabolite pattern of the MRJPs-fed aged rats was regressed to that of the young rats. Compounds altered by MRJPs were mapped to nicotinate and nicotinamide metabolism, cysteine taurine metabolism, and energy metabolism pathways. In summary, MRJPs may improve spatial memory and possess the potential for prevention of cognitive impairment via the cysteine and taurine metabolism and energy metabolism pathways in aged rats.
Libby, Laura A; Hannula, Deborah E; Ranganath, Charan
Several models have proposed that different medial temporal lobe (MTL) regions represent different kinds of information in the service of long-term memory. For instance, it has been proposed that perirhinal cortex (PRC), parahippocampal cortex (PHC), and hippocampus differentially support long-term memory for item information, spatial context, and item-context relations present during an event, respectively. Recent evidence has indicated that, in addition to long-term memory, MTL subregions may similarly contribute to processes that support the retention of complex spatial arrangements of objects across short delays. Here, we used functional magnetic resonance imaging and multivoxel pattern similarity analysis to investigate the extent to which human MTL regions independently code for object and spatial information, as well as the conjunction of this information, during working memory encoding and active maintenance. Voxel activity patterns in PRC, temporopolar cortex, and amygdala carried information about individual objects, whereas activity patterns in the PHC and posterior hippocampus carried information about the configuration of spatial locations that was to be remembered. Additionally, the integrity of multivoxel patterns in the right anterior hippocampus across encoding and delay periods was predictive of accurate short-term memory for object-location relationships. These results are consistent with parallel processing of item and spatial context information by PRC and PHC, respectively, and the binding of item and context by the hippocampus.
Hannula, Deborah E.; Ranganath, Charan
Several models have proposed that different medial temporal lobe (MTL) regions represent different kinds of information in the service of long-term memory. For instance, it has been proposed that perirhinal cortex (PRC), parahippocampal cortex (PHC), and hippocampus differentially support long-term memory for item information, spatial context, and item–context relations present during an event, respectively. Recent evidence has indicated that, in addition to long-term memory, MTL subregions may similarly contribute to processes that support the retention of complex spatial arrangements of objects across short delays. Here, we used functional magnetic resonance imaging and multivoxel pattern similarity analysis to investigate the extent to which human MTL regions independently code for object and spatial information, as well as the conjunction of this information, during working memory encoding and active maintenance. Voxel activity patterns in PRC, temporopolar cortex, and amygdala carried information about individual objects, whereas activity patterns in the PHC and posterior hippocampus carried information about the configuration of spatial locations that was to be remembered. Additionally, the integrity of multivoxel patterns in the right anterior hippocampus across encoding and delay periods was predictive of accurate short-term memory for object–location relationships. These results are consistent with parallel processing of item and spatial context information by PRC and PHC, respectively, and the binding of item and context by the hippocampus. PMID:25339737
Lee, Andy C H; Brodersen, Kay H; Rudebeck, Sarah R
Although the role of the hippocampus in spatial cognition is well accepted, it is unclear whether its involvement is restricted to the mnemonic domain or also extends to perception. We used fMRI to scan neurologically healthy participants during a scene oddity judgment task that placed no explicit demand on long-term memory. Crucially, a surprise recognition test was administered after scanning so that each trial could be categorized not only according to oddity accuracy but also according to subsequent memory. Univariate analyses showed significant hippocampal activity in association with correct oddity judgment, whereas greater parahippocampal place area (PPA) activity was observed during incorrect oddity trials, both irrespective of subsequent recognition performance. Consistent with this, multivariate pattern analyses revealed that a linear support vector machine was able to distinguish correct from incorrect oddity trials on the basis of activity in voxels within the hippocampus or PPA. Although no significant regions of activity were identified by univariate analyses in association with memory performance, a classifier was able to predict subsequent memory using voxels in either the hippocampus or PPA. Our findings are consistent with the idea that the hippocampus is important for processes beyond long-term declarative memory and that this structure may also play a role in complex spatial perception.
Kelly, Jonathan W.; McNamara, Timothy P.
Four experiments investigated the role of reference frames during the acquisition and development of spatial knowledge, when learning occurs incrementally across views. In two experiments, participants learned overlapping spatial layouts. Layout 1 was first studied in isolation, and Layout 2 was later studied in the presence of Layout 1. The…
Spritzer, Mark D.; Daviau, Emily D.; Coneeny, Meagan K.; Engelman, Shannon M.; Prince, W. Tyler; Rodriguez-Wisdom, Karlye N.
A male advantage over females for spatial tasks has been well documented in both humans and rodents, but it remains unclear how the activational effects of testosterone influence spatial ability in males. In a series of experiments, we tested how injections of testosterone influenced the spatial working and reference memory of castrated male rats. In the eight-arm radial maze, testosterone injections (0.500 mg/rat) reduced the number of working memory errors during the early blocks of testing but had no effect on the number of reference memory errors relative to the castrated control group. In a reference memory version of the Morris water maze, injections of a wide range of testosterone doses (0.0625-1.000 mg/rat) reduced path lengths to the hidden platform, indicative of improved spatial learning. This improved learning was independent of testosterone dose, with all treatment groups showing better performance than the castrated control males. Furthermore, this effect was only observed when rats were given testosterone injections starting seven days prior to water maze testing and not when injections were given only on the testing days. We also observed that certain doses of testosterone (0.250 and 1.000 mg/rat) increased perseverative behavior in a reversal-learning task. Finally, testosterone did not have a clear effect on spatial working memory in the Morris water maze, although intermediate doses seemed to optimize performance. Overall, the results indicate that testosterone can have positive activational effects on spatial learning and memory, but the duration of testosterone replacement and the nature of the spatial task modify these effects. PMID:21295035
Badcock, Johanna C; Michiel, Patricia T; Rock, Danny
Working memory may be conceptualized as a multi-component system involving the active maintenance and manipulation of stored information in the service of planning/guiding behaviour. Impaired spatial working memory is a robust finding in schizophrenia patients which has been related to an impairment in frontostriatal connectivity. The purpose of this study was to examine the specificity of this impairment by comparing the mnemonic and executive aspects of working memory performance in schizophrenia and bipolar disorder with psychotic features, focusing particularly on the functional dynamics between task components. Twenty-four patients with schizophrenia, 14 patients with bipolar I disorder (manic phase) and 33 healthy control subjects were assessed using the Cambridge Neuropsychological Test Automated Battery (CANTAB): including the spatial working memory (between search errors and strategy scores) spatial span (storage capacity) and spatial planning (Stockings of Cambridge: accuracy and latency) tasks. Both patient groups were impaired on the spatial span task, which requires the maintenance and retrieval of stored information. In contrast, only schizophrenia patients showed a significant deficit in between search errors, which requires both maintenance and manipulation of information in working memory. That is, they exhibited both a mnemonic and an executive dysfunction. Spatial span was particularly important to accurate planning ability in bipolar patients. In contrast, in patients with schizophrenia poor spatial working memory was a significant predictor of planning impairments, consistent with failures in goal selection, evaluation and/or execution. Furthermore, initial planning time was positively correlated with the latency to complete a planning sequence. This pattern of slow cognitive processing in schizophrenia patients only, resembled that reported previously in patients with basal ganglia disorders. These findings are discussed in terms of a possible
Tian, Qing; Zhang, Jun-Xia; Zhang, Yao; Wu, Feng; Tang, Qian; Wang, Cheng; Shi, Zhi-Yong; Zhang, Jing-Hui; Liu, Sang; Wang, Yue; Zhang, Qi; Wang, Jian-Zhi
To explore the role of protein kinase A (PKA) in regulating tau phosphorylation and spatial memory, we injected forskolin, an activator of PKA, at different concentrations into the rat brains. We found that forskolin at concentrations up to 80 microM enhanced tau phosphorylation and was associated with prominent spatial memory impairment. Higher concentrations of forskolin, up to 200 microM, were associated with reduced phosphorylation levels of tau and no memory deficits. Forskolin elevated cAMP and activated PKA in a dose-dependent manner. When infused at 200 microM, forskolin also resulted in the activation and overexpression of protein phosphatase-2A (PP-2A) and attenuated the okadaic acid-induced PP-2A inhibition. These data suggest that the upregulation of PKA by forskolin to a certain level may activate PP-2A but that the latter can ameliorate the PKA-induced tau phosphorylation and memory impairment in the rats.
Robin, Jessica; Moscovitch, Morris
Episodic memory, future thinking, and memory for scenes have all been proposed to rely on the hippocampus, and evidence suggests that these all decline in healthy aging. Despite this age-related memory decline, studies examining the effects of context reinstatement on episodic memory have demonstrated that reinstating elements of the encoding context of an event leads to better memory retrieval in both younger and older adults. The current study was designed to test whether more familiar, real-world contexts, such as locations that participants visited often, would improve the detail richness and vividness of memory for scenes, autobiographical events, and imagination of future events in young and older adults. The predicted age-related decline in internal details across all 3 conditions was accompanied by persistent effects of contextual familiarity, in which a more familiar spatial context led to increased detail and vividness of remembered scenes, autobiographical events, and, to some extent, imagined future events. This study demonstrates that autobiographical memory, imagination of the future, and scene memory are similarly affected by aging, and all benefit from being associated with more familiar (real-world) contexts, illustrating the stability of contextual reinstatement effects on memory throughout the life span. (PsycINFO Database Record
Shukitt-Hale, B.; Casadesus, G.; Carey, A.; Rabin, B. M.; Joseph, J. A.
Previous studies have shown that radiation exposure, particularly to particles of high energy and charge (HZE particles), produces deficits in spatial learning and memory. These adverse behavioral effects are similar to those seen in aged animals. It is possible that these shared effects may be produced by the same mechanism; oxidative stress damage to the central nervous system caused by an increased release of reactive oxygen species is likely responsible for the deficits seen in aging and following irradiation. Both aged and irradiated rats display cognitive impairment in tests of spatial learning and memory such as the Morris water maze and the radial arm maze. These rats have decrements in the ability to build spatial representations of the environment and they utilize non-spatial strategies to solve tasks. Furthermore, they show a lack of spatial preference, due to a decline in the ability to process or retain place (position of a goal with reference to a "map" provided by the configuration of numerous cues in the environment) information. These declines in spatial memory occur in measures dependent on both reference and working memory, and in the flexibility to reset mental images. These results show that irradiation with high-energy particles produces age-like decrements in cognitive behavior that may impair the ability of astronauts to perform critical tasks during long-term space travel beyond the magnetosphere. Supported by NASA Grants NAG9-1190 and NAG9-1529
Jarrold, Christopher; Phillips, Caroline; Baddeley, Alan D
A main aim of this study was to test the claim that individuals with Williams syndrome have selectively impaired memory for spatial as opposed to visual information. The performance of 16 individuals with Williams syndrome (six males, 10 females; mean age 18y 7mo [SD 7y 6mo], range 9y 1mo-30y 7mo) on tests of short-term memory for item and…
Akhlaghpour, Hessameddin; Wiskerke, Joost; Choi, Jung Yoon; Taliaferro, Joshua P; Au, Jennifer; Witten, Ilana B
Several lines of evidence suggest that the striatum has an important role in spatial working memory. The neural dynamics in the striatum have been described in tasks with short delay periods (1–4 s), but remain largely uncharacterized for tasks with longer delay periods. We collected and analyzed single unit recordings from the dorsomedial striatum of rats performing a spatial working memory task with delays up to 10 s. We found that neurons were activated sequentially, with the sequences spanning the entire delay period. Surprisingly, this sequential activity was dissociated from stimulus encoding activity, which was present in the same neurons, but preferentially appeared towards the onset of the delay period. These observations contrast with descriptions of sequential dynamics during similar tasks in other brains areas, and clarify the contribution of the striatum to spatial working memory. DOI: http://dx.doi.org/10.7554/eLife.19507.001 PMID:27636864
Czarnolewski, Mark Y; Eliot, John
Test scores of 119 students, attending either a public four-year college or a technical school, were related to their proportionality and detail drawing scores on the Memory for Designs Test. In regression models, the ETS Maze Tracing, Eliot-Price Mental Rotations, and Bender-Gestalt tests were consistent predictors of proportionality scores, with the latter two tests uniquely related to these. The ETS Shapes Memory Test and the Form Board Test were the strongest predictors for detail accuracy scores. The Shapes test predicted proportionality when the CTY Visual Memory Test BB was excluded. The models then provided support for the hypothesis that drawing designs from memory, a critical skill in drawing, regardless of whether one focuses on accuracy for proportionality scores or for detail scores, is jointly related to the measures of recognition, production, and traditional spatial ability measures. This study identified multifaceted skills in drawing from memory.
Gan, Qifeng; Seoud, Lama; Ben Tahar, Houssem; Langlois, J. M. Pierre
Spatial Averaging Filters (SAF) are extensively used in image processing for image smoothing and denoising. Their latest implementations have already achieved constant time computational complexity regardless of kernel size. However, all the existing O(1) algorithms require additional memory for temporary data storage. In order to minimize memory usage in embedded systems, we introduce a new two-dimensional recursive SAF. It uses previous resultant pixel values along both rows and columns to calculate the current one. It can achieve constant time computational complexity without using any additional memory usage. Experimental comparisons with previous SAF implementations shows that the proposed 2D-Recursive SAF does not require any additional memory while offering a computational time similar to the most efficient existing SAF algorithm. These features make it especially suitable for embedded systems with limited memory capacity.
Iwanaga, Makoto; Ito, Takako
The purpose of the present study was to examine the disturbance effect of music on performances of memory tasks. Subjects performed a verbal memory task and a spatial memory task in 4 sound conditions, including the presence of vocal music, instrumental music, a natural sound (murmurings of a stream), and no music. 47 undergraduate volunteers were randomly assigned to perform tasks under each condition. Perceived disturbance was highest under the vocal music condition regardless of the type of task. A disturbance in performance by music was observed only with the verbal memory task under the vocal and the instrumental music conditions. These findings were discussed from the perspectives of the working memory hypothesis and the changing state model.
Khabour, Omar F; Alzoubi, Karem H; Alomari, Mahmoud A; Alzubi, Mohammad A
Previous literature suggests that learning and memory formation can be influenced by diet and exercise. In the current study, we investigated the combined effects of forced swimming exercise (FSE) and every other day fasting (EODF) on spatial memory formation and on the levels of brain-derived neurotrophic factor (BDNF) in the hippocampus of Wistar male rats. The radial arm water maze (RAWM) paradigm was used to assess changes in learning and memory formation, whereas ELISA assay was used to measure BDNF protein levels. The FSE and/or EODF were simultaneously instituted for 6 weeks. Results show that FSE improved learning, short-term as well as long-term memory formation, and significantly increased BDNF protein in the hippocampus (p<0.05). However, EODF had no effect on either spatial learning and memory formation or the levels of hippocamapal BDNF protein (p>0.05). In addition, EODF did not modulate beneficial effect of swimming exercise on cognitive function (p>0.05). Thus exercise enhanced, while EODF did not affect spatial learning and memory formation.
Khabour, Omar F; Alzoubi, Karem H; Alomari, Mahmoud A; Alzubi, Mohammad A
Substantial data suggest that cognitive function can be influenced by many lifestyle activities associated with changes in energy metabolism such as exercise and diet. In the current study, we investigated the combined effects of voluntary exercise (access to running wheels) and dietary restriction (every other day fasting, EODF) on spatial memory formation and on the levels of brain-derived neurotrophic factor (BDNF) in the hippocampus of Wistar male rats. Spatial learning and memory formation was assessed using the radial arm water maze (RAWM) paradigm, while BDNF protein was measured using ELISA test. Voluntary exercise and/or EODF were instituted for 6 weeks. Voluntary exercise alone significantly enhanced short-term, intermediate-term, and long-term memory formation, and increased BDNF protein levels in the hippocampus. EODF enhanced mean running wheel activity by approximately twofold. However, EODF did not modulate the effects of exercise on memory formation and expression of BDNF. In addition, EODF alone had no effect on memory and BDNF protein in the hippocampus. In conclusion, results of this study indicate that exercise enhanced while EODF had neutral effect on both spatial memory formation and hippocampus BDNF levels.
Belnik, A P; Ostrovskaya, R U; Poletaeva, I I
The effect of original nootropic preparation Noopept on learning and long-term memory was studied with BALB/c mice. Scopolamine (1 mg/kg) impaired long-term memory trace, while Noopept (0.5 mg/kg) had no significant effect. Noopept completely prevented the development of cognitive disorders induced by scopolamine (blockade of muscarinic cholinergic receptors). Our results confirmed the presence of choline-positive effect in dipeptide piracetam analogue Noopept on retrieval of learned skill of finding a submerged platform (spatial memory). We conclude that the effectiveness of this drug should be evaluated in patients with Alzheimer's disease.
Iñiguez, Sergio D; Charntikov, Sergios; Baella, Shelley A; Herbert, Matthew S; Bolaños-Guzmán, Carlos A; Crawford, Cynthia A
In this study, we examined the ability of post-training injections of cocaine to facilitate spatial memory performance using the Morris water maze (MWM). We also investigated the role that hippocampal protein kinase A (PKA) and extracellular signal-regulated kinase 1/2 (ERK) signaling may play in cocaine-mediated spatial memory consolidation processes. Male and female C57BL/6 mice were first trained in a MWM task (eight consecutive trials) then injected with cocaine (0, 1.25, 2.5, 5, or 20 mg/kg), and memory for the platform location was retested after a 24 h delay. Cocaine had a dose-dependent effect on spatial memory performance because only the mice receiving 2.5 mg/kg cocaine displayed a significant reduction in latency to locate the platform. No sex differences in MWM performance were observed; however, females showed higher hippocampal levels of PKA when compared with males. A second experiment demonstrated that 2.5 mg/kg cocaine enhanced MWM performance only when administered within 2, but not 4 h after spatial training. We also found that cocaine (2.5 mg/kg) increased ERK2 phosphorylation within the hippocampus and one of its downstream targets (ribosomal S6 kinase), a mechanism that may be responsible, at least in part, for the enhanced cocaine-mediated spatial memory performance. Overall, these data demonstrate that a low dose of cocaine (2.5 mg/kg) administered within 2 h after training facilitates MWM spatial memory performance in C57BL/6 mice.
Thomson, Lisa M; Sutherland, Robert J
Sickness behaviors are a set of adaptive responses to infection that include lethargy, anorexia, and, of direct relevance to this work, learning and memory impairments. The proinflammatory cytokine, interleukin-1 beta (IL-1beta) has been proposed as the primary peripheral mediator of these sickness behaviors, though few studies have investigated the effects of peripheral IL-1beta on learning and memory. We used three different versions of the Morris water task (Morris water task), a spatial learning and memory task, to separately assess the effects of peripheral IL-1beta on acquisition, consolidation, and retention of spatial location information. Using a dose that induced anorexia, assessed as a significant reduction in body weight, we observed no performance impairments in the IL-1beta-treated rats across the different versions of the task, suggesting that peripheral IL-1beta alone is insufficient to induce spatial learning and memory impairments in the rat. The observed dissociation of anorexia and cognitive dysfunction suggests that, either spatial learning and memory are not principal components of the sickness response, or cognitive dysfunction requires different or additional peripheral mediator(s).
Lee, Sang Ah; Tucci, Valter; Vallortigara, Giorgio
Research across the cognitive and brain sciences has begun to elucidate some of the processes that guide navigation and spatial memory. Boundary geometry and featural landmarks are two distinct classes of environmental cues that have dissociable neural correlates in spatial representation and follow different patterns of learning. Consequently, spatial navigation depends both on the type of cue available and on the type of learning provided. We investigated this interaction between spatial representation and memory by administering two different tasks (working memory, reference memory) using two different environmental cues (rectangular geometry, striped landmark) in mouse models of human genetic disorders: Prader-Willi syndrome (PWScr(m+/p-) mice, n = 12) and Beta-catenin mutation (Thr653Lys-substituted mice, n = 12). This exploratory study provides suggestive evidence that these models exhibit different abilities and impairments in navigating by boundary geometry and featural landmarks, depending on the type of memory task administered. We discuss these data in light of the specific deficits in cognitive and brain function in these human syndromes and their animal model counterparts.
Shea, Chloe J A; Carhuatanta, Kimberly A K; Wagner, Jessica; Bechmann, Naomi; Moore, Raquel; Herman, James P; Jankord, Ryan
The effects of chronic stress on learning are highly variable across individuals. This variability stems from gene-environment interactions. However, the mechanisms by which stress affects genetic predictors of learning are unclear. Thus, we aim to determine whether the genetic pathways that predict spatial memory performance are altered by previous exposure to chronic stress. Sixty-two BXD recombinant inbred strains of mice, as well as parent strains C57BL/6J and DBA/2J, were randomly assigned as behavioral control or to a chronic variable stress paradigm and then underwent behavioral testing to assess spatial memory and learning performance using the Morris water maze. Quantitative trait loci (QTL) mapping was completed for average escape latency times for both control and stress animals. Loci on chromosomes 5 and 10 were found in both control and stress environmental populations; eight additional loci were found to be unique to either the control or stress environment. In sum, results indicate that certain genetic loci predict spatial memory performance regardless of prior stress exposure, while exposure to stress also reveals unique genetic predictors of training during the memory task. Thus, we find that genetic predictors contributing to spatial learning and memory are susceptible to the presence of chronic stress.
Sirichoat, Apiwat; Chaijaroonkhanarak, Wunnee; Prachaney, Parichat; Pannangrong, Wanassanan; Leksomboon, Ratana; Chaichun, Amnart; Wigmore, Peter; Welbat, Jariya Umka
Asiatic acid is a pentacyclic triterpene from Centella asiatica. Previous studies have reported that asiatic acid exhibits antioxidant and neuroprotective activities in cell culture. It also prevents memory deficits in animal models. The objective of this study was to investigate the relationship between spatial working memory and changes in cell proliferation within the hippocampus after administration of asiatic acid to male Spraque-Dawley rats. Control rats received vehicle (propylene glycol) while treated rats received asiatic acid (30 mg/kg) orally for 14 or 28 days. Spatial memory was determined using the novel object location (NOL) test. In animals administered asiatic acid for both 14 and 28 days, the number of Ki-67 positive cells in the subgranular zone of the dentate gyrus was significantly higher than in control animals. This was associated with a significant increase in their ability to discriminate between novel and familiar object locations in a novel object discrimination task, a hippocampus-dependent spatial memory test. Administration of asiatic acid also significantly increased doublecortin (DCX) and Notch1 protein levels in the hippocampus. These findings demonstrate that asiatic acid treatment may be a potent cognitive enhancer which improves hippocampal-dependent spatial memory, likely by increasing hippocampal neurogenesis.
Zhu, Xiaolin; Sun, Wei; Li, Xinwang; Tan, Shuping; Zhang, Xiangyang
Drug addiction is associated with memory processes. We simultaneously measured conditioned place preference (CPP) and locomotor sensitization to investigate the influence of spatial memory retrieval on morphine reward and psychomotor excitement. According to their performance in space probe trial involving the Morris water maze mice were assigned to high (including morphine and saline subgroups, H-Mor and H-Sal) and low spatial memory retrieval ability groups (L-Mor and L-Sal). Morphine (10mg/kg) produced significant CPP in L-Mor and H-Mor mice, although, L-Mor mice showed a significantly greater response to morphine. During the development period of behavior sensitization, no significant group-by-day interaction was found. However, locomotor activities of L-Mor mice were also significantly higher than H-Mor mice during the expression period of behavior sensitization. Our findings suggested that the spatial memory retrieval ability of mice influences morphine CPP, as well as behavioral sensitization. Thus, spatial memory might be implicated in drug addiction.
Sirichoat, Apiwat; Chaijaroonkhanarak, Wunnee; Prachaney, Parichat; Pannangrong, Wanassanan; Leksomboon, Ratana; Chaichun, Amnart; Wigmore, Peter; Umka Welbat, Jariya
Asiatic acid is a pentacyclic triterpene from Centella asiatica. Previous studies have reported that asiatic acid exhibits antioxidant and neuroprotective activities in cell culture. It also prevents memory deficits in animal models. The objective of this study was to investigate the relationship between spatial working memory and changes in cell proliferation within the hippocampus after administration of asiatic acid to male Spraque-Dawley rats. Control rats received vehicle (propylene glycol) while treated rats received asiatic acid (30 mg/kg) orally for 14 or 28 days. Spatial memory was determined using the novel object location (NOL) test. In animals administered asiatic acid for both 14 and 28 days, the number of Ki-67 positive cells in the subgranular zone of the dentate gyrus was significantly higher than in control animals. This was associated with a significant increase in their ability to discriminate between novel and familiar object locations in a novel object discrimination task, a hippocampus-dependent spatial memory test. Administration of asiatic acid also significantly increased doublecortin (DCX) and Notch1 protein levels in the hippocampus. These findings demonstrate that asiatic acid treatment may be a potent cognitive enhancer which improves hippocampal-dependent spatial memory, likely by increasing hippocampal neurogenesis. PMID:26445061
Lee, Sang Ah; Tucci, Valter; Vallortigara, Giorgio
Research across the cognitive and brain sciences has begun to elucidate some of the processes that guide navigation and spatial memory. Boundary geometry and featural landmarks are two distinct classes of environmental cues that have dissociable neural correlates in spatial representation and follow different patterns of learning. Consequently, spatial navigation depends both on the type of cue available and on the type of learning provided. We investigated this interaction between spatial representation and memory by administering two different tasks (working memory, reference memory) using two different environmental cues (rectangular geometry, striped landmark) in mouse models of human genetic disorders: Prader-Willi syndrome (PWScrm+/p− mice, n = 12) and Beta-catenin mutation (Thr653Lys-substituted mice, n = 12). This exploratory study provides suggestive evidence that these models exhibit different abilities and impairments in navigating by boundary geometry and featural landmarks, depending on the type of memory task administered. We discuss these data in light of the specific deficits in cognitive and brain function in these human syndromes and their animal model counterparts. PMID:28208764
Spiers, Mary V; Sakamoto, Maiko; Elliott, Richard J; Baumann, Steve
The grocery shopping Virtual Reality Spatial Object-Location Test (VRSOLT) was developed to examine sex differences in spatial object-location memory in a 3D virtual environment that simulates the real world. Forty college students (20 males, 20 females) were tested on the VRSOLT as well as mental rotation and 2D object-location memory tasks. Both convergent and divergent validity was demonstrated. Males showed an advantage on mental rotation, and results of the VRSOLT grocery store test replicated the female object-location advantage seen in 2D tests. A strategy of systematically navigating the environment may aid female encoding for object location.
Wang, Qing M.; Meng, Zhaoxiang; Yin, Zhenglu
Objective To investigate whether gait dysfunction is a predictor of severe spatial learning and memory impairment in aged mice. Methods A total of 100 12-month-old male mice that had no obvious abnormal motor ability and whose Morris water maze performances were not significantly different from those of two-month-old male mice were selected for the study. The selected aged mice were then divided into abnormal or normal gait groups according to the results from the quantitative gait assessment. Gaits of aged mice were defined as abnormal when the values of quantitative gait parameters were two standard deviations (SD) lower or higher than those of 2-month-old male mice. Gait parameters included stride length, variability of stride length, base of support, cadence, and average speed. After nine months, mice exhibiting severe spatial learning and memory impairment were separated from mice with mild or no cognitive dysfunction. The rate of severe spatial learning and memory impairment in the abnormal and normal gait groups was tested by a chi-square test and the correlation between gait dysfunction and decline in cognitive function was tested using a diagnostic test. Results The 12-month-old aged mice were divided into a normal gait group (n = 75) and an abnormal gait group (n = 25). Nine months later, three mice in the normal gait group and two mice in the abnormal gait group had died. The remaining mice were subjected to the Morris water maze again, and 17 out of 23 mice in the abnormal gait group had developed severe spatial learning and memory impairment, including six with stride length deficits, 15 with coefficient of variation (CV) in stride length, two with base of support (BOS) deficits, five with cadence dysfunction, and six with average speed deficits. In contrast, only 15 out of 72 mice in the normal gait group developed severe spatial learning and memory impairment. The rate of severe spatial learning and memory impairment was significantly higher in
Navawongse, Rapeechai; Eichenbaum, Howard
Hippocampal neurons encode events within the context in which they occurred, a fundamental feature of episodic memory. Here we explored the sources of event and context information represented by hippocampal neurons during the retrieval of object associations in rats. Temporary inactivation of the medial prefrontal cortex differentially reduced the selectivity of rule-based object associations represented by hippocampal neuronal firing patterns but did not affect spatial firing patterns. By contrast, inactivation of the medial entorhinal cortex resulted in a pervasive reorganization of hippocampal mappings of spatial context and events. These results suggest distinct and cooperative prefrontal and medial temporal mechanisms in memory representation. PMID:23325238
Clark, Kelsey L; Noudoost, Behrad; Moore, Tirin
Spatial attention is known to gate entry into visual short-term memory, and some evidence suggests that spatial signals may also play a role in binding features or protecting object representations during memory maintenance. To examine the persistence of spatial signals during object short-term memory, the activity of neurons in the frontal eye field (FEF) of macaque monkeys was recorded during an object-based delayed match-to-sample task. In this task, monkeys were trained to remember an object image over a brief delay, regardless of the locations of the sample or target presentation. FEF neurons exhibited visual, delay, and target period activity, including selectivity for sample location and target location. Delay period activity represented the sample location throughout the delay, despite the irrelevance of spatial information for successful task completion. Furthermore, neurons continued to encode sample position in a variant of the task in which the matching stimulus never appeared in their response field, confirming that FEF maintains sample location independent of subsequent behavioral relevance. FEF neurons also exhibited target-position-dependent anticipatory activity immediately before target onset, suggesting that monkeys predicted target position within blocks. These results show that FEF neurons maintain spatial information during short-term memory, even when that information is irrelevant for task performance.
Richmond, Jenny L; Zhao, Jenna L; Burns, Mary A
Episodic memory involves binding components of an event (who, what, when, and where) into a relational representation. The ability to encode information about the relative locations of objects (i.e., spatial relational memory) is a key component of episodic memory. Here we used eye tracking to test whether infants and toddlers learn about the spatial relations among objects. In Experiment 1, 9-, 18-, and 27-month olds were familiarized with an array of three objects. Following familiarization, they saw test arrays in which two of the objects had been replaced with novel ones (object switch condition) and arrays in which two of the objects had switched positions (location switch condition). Both 18- and 27-month olds looked significantly longer than would be predicted by chance at the objects that had switched spatial locations; however, 9-month olds did not. In Experiment 2, we showed that, given sufficient familiarization time, 9-month olds were also capable of detecting disruptions to the spatial relations among an array of objects. These results have important implications for our understanding of spatial relational memory development.
Boon, Paul J.; Belopolsky, Artem V.; Theeuwes, Jan
Visual-spatial working memory (VSWM) helps us to maintain and manipulate visual information in the absence of sensory input. It has been proposed that VSWM is an emergent property of the oculomotor system. In the present study we investigated the role of the oculomotor system in updating of spatial working memory representations across saccades. Participants had to maintain a location in memory while making a saccade to a different location. During the saccade the target was displaced, which went unnoticed by the participants. After executing the saccade, participants had to indicate the memorized location. If memory updating fully relies on cancellation driven by extraretinal oculomotor signals, the displacement should have no effect on the perceived location of the memorized stimulus. However, if postsaccadic retinal information about the location of the saccade target is used, the perceived location will be shifted according to the target displacement. As it has been suggested that maintenance of accurate spatial representations across saccades is especially important for action control, we used different ways of reporting the location held in memory; a match-to-sample task, a mouse click or by making another saccade. The results showed a small systematic target displacement bias in all response modalities. Parametric manipulation of the distance between the to-be-memorized stimulus and saccade target revealed that target displacement bias increased over time and changed its spatial profile from being initially centered on locations around the saccade target to becoming spatially global. Taken together results suggest that we neither rely exclusively on extraretinal nor on retinal information in updating working memory representations across saccades. The relative contribution of retinal signals is not fixed but depends on both the time available to integrate these signals as well as the distance between the saccade target and the remembered location. PMID
Vilela, Thais Ceresér; Muller, Alexandre Pastoris; Damiani, Adriani Paganini; Macan, Tamires Pavei; da Silva, Sabrina; Canteiro, Paula Bortoluzzi; de Sena Casagrande, Alisson; Pedroso, Giulia Dos Santos; Nesi, Renata Tiscoski; de Andrade, Vanessa Moraes; de Pinho, Ricardo Aurino
Aging is associated with impaired cognition and memory and increased susceptibility to neurodegenerative disorders. Physical exercise is neuroprotective; however, the major evidence of this effect involves studies of only aerobic training in young animals. The benefits of other exercise protocols such as strength training in aged animals remains unknown. Here, we investigated the effect of aerobic and strength training on spatial memory and hippocampal plasticity in aging rats. Aging Wistar rats performed aerobic or strength training for 50 min 3 to 4 days/week for 8 weeks. Spatial memory and neurotrophic and glutamatergic signaling in the hippocampus of aged rats were evaluated after aerobic or strength training. Both aerobic and strength training improved cognition during the performance of a spatial memory task. Remarkably, the improvement in spatial memory was accompanied by an increase in synaptic plasticity proteins within the hippocampus after exercise training, with some differences in the intracellular functions of those proteins between the two exercise protocols. Moreover, neurotrophic signaling (CREB, BDNF, and the P75(NTR) receptor) increased after training for both exercise protocols, and aerobic exercise specifically increased glutamatergic proteins (NMDA receptor and PSD-95). We also observed a decrease in DNA damage after aerobic training. In contrast, strength training increased levels of PKCα and the proinflammatory factors TNF-α and IL-1β. Overall, our results show that both aerobic and strength training improved spatial memory in aging rats through inducing distinct molecular mechanisms of neuroplasticity. Our findings extend the idea that exercise protocols can be used to improve cognition during aging.
Kumar, Navnit; Priyadarshi, Brajesh
Working memory (WM) declines with age. However it seems unclear, whether age related decline is more pronounced on verbal WM or on visuo-spatial WM. The present study compares the effect of aging on verbal and visuo-spatial modality of WM on native Hindi healthy speakers, in the age range of 40-to-above 80 years. It was found that normal aging affect both the verbal and visual working memory in similar way. Both modality declines with a similar rate up to 50–60 years and after 60 years relative saturation in span take place. Although verbal WM span is higher than visuo-spatial WM span, but no significant difference between verbal and visuo-spatial WM span were observed. PMID:23946892
Martin, G N; Chaudry, A
Sensory influences on working memory (WM) performance were investigated in 86 healthy adults. Participants were exposed to an ambient pleasant odor (lemon), unpleasant odor (machine oil) or no odor during completion of three WM tests from the Wechsler Memory Scale-III: the letter-number sequencing, spatial span and digit span tests. A significant main effect of odor was found for spatial span but no other task: scores were significantly lower in the unpleasant odor condition than the pleasant odor condition. Significant odor × sex interactions were found for the spatial span, digit span and letter-number sequencing tasks: men's spatial span scores were lower in the unpleasant odor condition than in the control condition, and women's scores were significantly better in the pleasant odor condition than in the unpleasant odor condition. The results suggest that ambient odor may impair or facilitate specific types of WM depending on the task, sex of the participant and affective characteristics of the odor.
Piccardi, L; Bianchini, F; Nori, R; Marano, A; Iachini, F; Lasala, L; Guariglia, C
Spatial information processing is influenced by the space in which an individual acts and the nature of the stimulus. This distinction is also present in spatial memory, where stimuli are processed differently because of their nature and the space in which they are released. The aim of the present study was to compare college students' performance on spatial location and pathway memory tasks in two different domains (reaching and walking). Reaching space refers to the portion of space within "grasping distance" and walking space to that beyond arm's reach. Research results indicate that it is easier to remember a pathway in the walking than the reaching domain and to remember single spatial locations in the reaching domain. Women are more able to perform the task in the walking domain than the reaching domain and men perform equally well in both domains.
Kelly, Jonathan W.; Avraamides, Marios N.
Two experiments investigated whether visual cues influence spatial reference frame selection for locations learned through touch. Participants experienced visual cues emphasizing specific environmental axes and later learned objects through touch. Visual cues were manipulated and haptic learning conditions were held constant. Imagined perspective…
Darling, S; Della Sala, S; Logie, R H; Cantagallo, A
There is increasing evidence to support the idea that visuo-spatial working memory can be segregated into separate cognitive subsystems. However, the nature of these systems remains unclear. In this paper we report data from two brain injured patients suggesting that information about visual appearance is retained in a different subsystem from information about spatial location, and that this differential processing can be observed when the style of presentation (sequential or simultaneous) is controlled.
Kida, Kumiko; Tsuji, Tadataka; Tanaka, Susumu; Kogo, Mikihiko
Sufficient oral microelements such as zinc and fully chewing of foods are required to maintain cognitive function despite aging. No knowledge exists about the combination of factors such as zinc deficiency and reduced mastication on learning and memory. Here we show that tooth extraction only in 8-week-old mice did not change the density of glial fibrillary acidic protein-labeled astrocytes in the hippocampus or spatial memory parameters. However, tooth extraction followed by zinc deprivation strongly impaired spatial memory and led to an increase in astrocytic density in the hippocampal CA1 region. The impaired spatial performance in the zinc-deficient only (ZD) mice also coincided well with the increase in the astrocytic density in the hippocampal CA1 region. After switching both zinc-deficient groups to a normal diet with sufficient zinc, spatial memory recovered, and more time was spent in the quadrant with the goal in the probe test in the mice with tooth extraction followed by zinc deprivation (EZD) compared to the ZD mice. Interestingly, we found no differences in astrocytic density in the CA1 region among all groups at 22 weeks of age. Furthermore, the escape latency in a visible probe test at all times was longer in zinc-deficient groups than the others and demonstrated a negative correlation with body weight. No significant differences in escape latency were observed in the visible probe test among the ZD, EZD, and normal-fed control at 4 weeks (CT4w) groups in which body weight was standardized to that of the EZD group, or in the daily reduction in latency between the normal-fed control and CT4w groups. Our data showed that zinc-deficient feeding during a young age impairs spatial memory performance and leads to an increase in astrocytic density in the hippocampal CA1 region and that zinc-sufficient feeding is followed by recovery of the impaired spatial memory along with changes in astrocytic density. The combination of the two factors, zinc deficiency
Paul, Carrillo-Mora; Magda, Giordano; Abel, Santamaría
The assessment of learning and memory in animal models has been widely employed in scientific research for a long time. Among these models, those representing diseases with primary processes of affected memory - such as amnesia, dementia, brain aging, etc. - studies dealing with the toxic effects of specific drugs, and other exploring neurodevelopment, trauma, epilepsy and neuropsychiatric disorders, are often called on to employ these tools. There is a diversity of experimental methods assessing animal learning and memory skills. Overall, mazes are the devices mostly used today to test memory in rodents; there are several types of them, but their real usefulness, advantages and applications remain to be fully established and depend on the particular variant selected by the experimenter. The aims of the present article are first, to briefly review the accumulated knowledge in regard to spatial memory tasks; second, to bring the reader information on the different types of rodent mazes available to test spatial memory; and third, to elucidate the usefulness and limitations of each of these devices.
Katus, Tobias; Andersen, Søren K; Müller, Matthias M
Orienting attention to locations in mnemonic representations engages processes that functionally and anatomically overlap the neural circuitry guiding prospective shifts of spatial attention. The attention-based rehearsal account predicts that the requirement to withdraw attention from a memorized location impairs memory accuracy. In a dual-task study, we simultaneously presented retro-cues and pre-cues to guide spatial attention in short-term memory (STM) and perception, respectively. The spatial direction of each cue was independent of the other. The locations indicated by the combined cues could be compatible (same hand) or incompatible (opposite hands). Incompatible directional cues decreased lateralized activity in brain potentials evoked by visual cues, indicating interference in the generation of prospective attention shifts. The detection of external stimuli at the prospectively cued location was impaired when the memorized location was part of the perceptually ignored hand. The disruption of attention-based rehearsal by means of incompatible pre-cues reduced memory accuracy and affected encoding of tactile test stimuli at the retrospectively cued hand. These findings highlight the functional significance of spatial attention for spatial STM. The bidirectional interactions between both tasks demonstrate that spatial attention is a shared neural resource of a capacity-limited system that regulates information processing in internal and external stimulus representations.
Wheelan, Nicola; Webster, Scott P.; Kenyon, Christopher J.; Caughey, Sarah; Walker, Brian R.; Holmes, Megan C.; Seckl, Jonathan R.; Yau, Joyce L.W.
High glucocorticoid levels induced by stress enhance the memory of fearful events and may contribute to the development of anxiety and posttraumatic stress disorder. In contrast, elevated glucocorticoids associated with ageing impair spatial memory. We have previously shown that pharmacological inhibition of the intracellular glucocorticoid-amplifying enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) improves spatial memory in aged mice. However, it is not known whether inhibition of 11β-HSD1 will have any beneficial effects on contextual fear memories in aged mice. Here, we examined the effects of UE2316, a selective 11β-HSD1 inhibitor which accesses the brain, on both spatial and contextual fear memories in aged mice using a vehicle-controlled crossover study design. Short-term UE2316 treatment improved spatial memory in aged mice, an effect which was reversed when UE2316 was substituted with vehicle. In contrast, contextual fear memory induced by foot-shock conditioning was significantly reduced by UE2316 in a non-reversible manner. When the order of treatment was reversed following extinction of the original fear memory, and a second foot-shock conditioning was given in a novel context, UE2316 treated aged mice (previously on vehicle) now showed increased fear memory compared to vehicle-treated aged mice (previously on UE2316). Renewal of the original extinguished fear memory triggered by exposure to a new environmental context may explain these effects. Thus 11β-HSD1 inhibition reverses spatial memory impairments with ageing while reducing the strength and persistence of new contextual fear memories. Potentially this could help prevent anxiety-related disorders in vulnerable elderly individuals. PMID:25497454
Wheelan, Nicola; Webster, Scott P; Kenyon, Christopher J; Caughey, Sarah; Walker, Brian R; Holmes, Megan C; Seckl, Jonathan R; Yau, Joyce L W
High glucocorticoid levels induced by stress enhance the memory of fearful events and may contribute to the development of anxiety and posttraumatic stress disorder. In contrast, elevated glucocorticoids associated with ageing impair spatial memory. We have previously shown that pharmacological inhibition of the intracellular glucocorticoid-amplifying enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) improves spatial memory in aged mice. However, it is not known whether inhibition of 11β-HSD1 will have any beneficial effects on contextual fear memories in aged mice. Here, we examined the effects of UE2316, a selective 11β-HSD1 inhibitor which accesses the brain, on both spatial and contextual fear memories in aged mice using a vehicle-controlled crossover study design. Short-term UE2316 treatment improved spatial memory in aged mice, an effect which was reversed when UE2316 was substituted with vehicle. In contrast, contextual fear memory induced by foot-shock conditioning was significantly reduced by UE2316 in a non-reversible manner. When the order of treatment was reversed following extinction of the original fear memory, and a second foot-shock conditioning was given in a novel context, UE2316 treated aged mice (previously on vehicle) now showed increased fear memory compared to vehicle-treated aged mice (previously on UE2316). Renewal of the original extinguished fear memory triggered by exposure to a new environmental context may explain these effects. Thus 11β-HSD1 inhibition reverses spatial memory impairments with ageing while reducing the strength and persistence of new contextual fear memories. Potentially this could help prevent anxiety-related disorders in vulnerable elderly individuals.
Goldstein, Kim E; Hazlett, Erin A; Savage, Kimberley R; Berlin, Heather A; Hamilton, Holly K; Zelmanova, Yuliya; Look, Amy E; Koenigsberg, Harold W; Mitsis, Effie M; Tang, Cheuk Y; McNamara, Margaret; Siever, Larry J; Cohen, Barry H; New, Antonia S
Schizotypal personality disorder (SPD) individuals and borderline personality disorder (BPD) individuals have been reported to show neuropsychological impairments and abnormalities in brain structure. However, relationships between neuropsychological function and brain structure in these groups are not well understood. This study compared visual-spatial working memory (SWM) and its associations with dorsolateral prefrontal cortex (DLPFC) and ventrolateral prefrontal cortex (VLPFC) gray matter volume in 18 unmedicated SPD patients with no BPD traits, 18 unmedicated BPD patients with no SPD traits, and 16 healthy controls (HC). Results showed impaired SWM in SPD but not BPD, compared with HC. Moreover, among the HC group, but not SPD patients, better SWM performance was associated with larger VLPFC (BA44/45) gray matter volume (Fisher's Z p-values <0.05). Findings suggest spatial working memory impairments may be a core neuropsychological deficit specific to SPD patients and highlight the role of VLPFC subcomponents in normal and dysfunctional memory performance.
Hritcu, Lucian; Cioanca, Oana; Hancianu, Monica
Lavender is reported to be an effective medical plant in treating inflammation, depression, stress and mild anxiety in Europe and the USA. The present study investigated the effects of two different lavender essential oils from Lavandula angustifolia ssp. angustifolia Mill. (Lamiaceae) and Lavandula hybrida Rev. (Lamiaceae) on neurological capacity of male Wistar rats subjected to scopolamine (0.7mg/kg)-induced dementia rat model. Chronic exposures to lavender essential oils (daily, for 7 continuous days) significantly reduced anxiety-like behavior and inhibited depression in elevated plus-maze and forced swimming tests, suggesting anxiolytic and antidepressant activity. Also, spatial memory performance in Y-maze and radial arm-maze tasks was improved, suggesting positive effects on memory formation. Taken together, multiple exposures to lavender essential oils could effectively reverse spatial memory deficits induced by dysfunction of the cholinergic system in the rat brain and might provide an opportunity for management neurological abnormalities in dementia conditions.
Meneghetti, Chiara; De Beni, Rossana; Gyselinck, Valérie; Pazzaglia, Francesca
The study investigates the relationships between working memory (WM), amount of learning, and strategies used in spatial description. WM involvement and strategies reported were assumed to change, depending on whether the text learning was extensive or limited. Two experiments were carried out using dual-task paradigm: participants listened to spatial text three times and concurrently one group performed a spatial concurrent task, one group a verbal task (to measure WM involvement), and one group no secondary task. In Experiment 1, participants listened three consecutive times then performed recall tasks (one verbal - verification test; one spatial - graphical representation). In Experiment 2, recall tasks were performed after first and third listening. The strategies used were ascertained through a questionnaire. Results showed that the verification test was impaired by the verbal concurrent task after listening three times (Experiment 1) and after first listening (Experiment 2). The graphical representation performance was impaired by verbal and spatial concurrent tasks, detected only after listening three times, not after a single time (Experiments 1 and 2). The strategies most used were visuo-spatial; their relationship with WM changes as a function of number of times of listening. Overall, the results showed that extensive learning allows construction of a spatial mental representation that is modulated by WM and strategies.
Mou, Weimin; Xiao, Chengli; McNamara, Timothy P.
Two experiments investigated participants' spatial memory of a briefly viewed layout. Participants saw an array of five objects on a table and, after a short delay, indicated whether the target object indicated by the experimenter had been moved. Experiment 1 showed that change detection was more accurate when non-target objects were stationary…
Lalonde, Jasmin; Chaudhuri, Avi
Discrimination thresholds were obtained using a delayed spatial frequency discrimination task. In Experiment 1, we found that presentation of a mask 3 s before onset of a reference Gabor patch caused a selective, spatial frequency dependent interference in a subsequent discrimination task. However, a 10 s interval abolished this masking effect. In Experiment 2, the mask was associated with a second spatial frequency discrimination task so that a representation of the mask had to be coded into short-term perceptual memory. This experiment was performed to assess whether absence of masking in the 10 s condition of Experiment 1 might be due to decay of the mask information in the perceptual or the memory representational domain. The presence of this second discrimination task now caused similar interference effects on the primary discrimination task at both the 3 s and 10 s interstimulus intervals (ISI) conditions. Finally, to test the robustness of the masking effect, the nature of the secondary masking task was changed from a spatial frequency discrimination task to an orientation discrimination task in Experiment 3. The masking effect was now abolished in both the 3 and 10 s ISI conditions. Together, the results from these experiments are consistent with the idea of a two-level perceptual memory mechanism. The results also suggest that stimulus representations during a perceptual discrimination task are shared between the perceptual and memory representation domains in a task-dependent manner.
Rodríguez, Fernando; López, J Carlos; Vargas, J Pedro; Gómez, Yolanda; Broglio, Cristina; Salas, Cosme
The hippocampus of mammals and birds is critical for spatial memory. Neuroanatomical evidence indicates that the medial cortex (MC) of reptiles and the lateral pallium (LP) of ray-finned fishes could be homologous to the hippocampus of mammals and birds. In this work, we studied the effects of lesions to the MC of turtles and to the LP of goldfish in spatial memory. Lesioned animals were trained in place, and cue maze tasks and crucial probe and transfer tests were performed. In experiment 1, MC-lesioned turtles in the place task failed to locate the goal during trials in which new start positions were used, whereas sham animals navigated directly to the goal independently of start location. In contrast, no deficit was observed in cue learning. In experiment 2, LP lesion produced a dramatic impairment in goldfish trained in the place task, whereas medial and dorsal pallium lesions did not decrease accuracy. In addition, none of these pallial lesions produced deficits in cue learning. These results indicate that lesions to the MC of turtles and to the LP of goldfish, like hippocampal lesions in mammals and birds, selectively impair map-like memory representations of the environmental space. Thus, the forebrain structures of reptiles and teleost fish neuroanatomically equivalent to the mammalian and avian hippocampus also share a central role in spatial cognition. Present results suggest that the presence of a hippocampus-dependent spatial memory system is a primitive feature of the vertebrate forebrain that has been conserved through evolution.
Ortmann, Margaret R.; Schutte, Anne R.
Early in development, there is a transition in spatial working memory (SWM). When remembering a location in a homogeneous space (e.g., in a sandbox), young children are biased toward the midline symmetry axis of the space. Over development, a transition occurs that leads to older children being biased away from midline. The dynamic field theory…
Wallentin, Mikkel; Kristensen, Line Burholt; Olsen, Jacob Hedeager; Nielsen, Andreas Hojlund
The brain's frontal eye fields (FEF), responsible for eye movement control, are known to be involved in spatial working memory (WM). In a previous fMRI experiment (Wallentin, Roepstorff & Burgess, Neuropsychologia, 2008) it was found that FEF activation was primarily related to the formation of an object-centered, rather than egocentric, spatial…
Schroeder, Anna; Hudson, Matthew; Du, Xin; Wu, Yee Wen Candace; Nakamura, Jay; van den Buuse, Maarten; Jones, Nigel C; Hill, Rachel A
Previous work suggests that estradiol regulates the expression of hippocampal parvalbumin as well as hippocampus-dependent spatial memory in mice. Parvalbumin interneurons generate neuronal oscillatory activity in the gamma frequency range (30-80Hz) and gamma oscillations are closely linked with higher cognitive functions. Raloxifene, a selective estrogen receptor modulator, shows beneficial effects on human cognitive performance, and has few peripheral side effects unlike estradiol, but the biological mechanisms which underpin these benefits are not clear. This study aimed to investigate whether estradiol and raloxifene modulate hippocampal gamma-band oscillations during spatial memory performance. Prepubescent female mice were ovariectomized (OVX) and implanted with a subcutaneous pellet of either estradiol (E2), raloxifene or placebo. During adulthood, local field potentials were recorded from the dorsal hippocampus while mice were performing the Y-maze hippocampus-dependent spatial memory task. Ovariectomy caused deficits in spatial memory, accompanied by a significant reduction in hippocampal gamma oscillations, specifically during decision making. Estradiol as well as raloxifene rescued both behavioural and electrophysiological deficits. These data have significant implications for disorders of cognitive impairment where altered gamma oscillations are apparent, such as schizophrenia.
Vestergaard, Martin; Madsen, Kathrine Skak; Baare, William F. C.; Skimminge, Arnold; Ejersbo, Lisser Rye; Ramsoy, Thomas Z.; Gerlach, Christian; Akeson, Per; Paulson, Olaf B.; Jernigan, Terry L.
During childhood and adolescence, ongoing white matter maturation in the fronto-parietal cortices and connecting fiber tracts is measurable with diffusion-weighted imaging. Important questions remain, however, about the links between these changes and developing cognitive functions. Spatial working memory (SWM) performance improves significantly…
Guidi, Michael; Rani, Asha; Karic, Semir; Severance, Barrett; Kumar, Ashok; Foster, Thomas C
A decrease in N-methyl-D-aspartate receptor (NMDAR) function is associated with age-related cognitive impairments. However, NMDAR antagonists are prescribed for cognitive decline associated with age-related neurodegenerative disease, raising questions as to the role of NMDAR activity in cognitive function during aging. The current studies examined effects of NMDAR blockade on cognitive task that are sensitive to aging. Young and middle-age rats were trained on the five-choice serial reaction time task (5-CSRTT) and challenged with MK-801 (0.025, 0.05, and 0.1mg/kg or vehicle). Attention deficits were apparent in middle-age and performance of young and middle-age rats was enhanced for low doses of MK-801 (0.025 and 0.05). The beneficial effects on attention were reversed by the highest dose of MK-801. Older animals exhibited a delay-dependent impairment of episodic spatial memory examined on a delayed-matching to place water maze task. Similarly, a low dose of MK-801 (0.05mg/kg) impaired performance with increasing delay and aged animals were more susceptible to disruption by NMDAR blockade. Despite MK-801 impairment of episodic spatial memory, MK-801 had minimal effects on spatial reference memory. Our results confirm that NMDARs contribute to rapidly acquired and flexible spatial memory and support the idea that a decline in NMDAR function contributes to the age-related impairments in cognition.
Mahmoudi, Ali; Hosseini-Sharifabad, Ali; Monsef-Esfahani, Hamid R; Yazdinejad, Ali R; Khanavi, Mahnaz; Roghani, Ali; Beyer, Cordian; Sharifzadeh, Mohammad
Time-dependent effects of ethanolic extract of Boswellia papyrifera, administered systemically, on spatial memory retention in the Morris water maze were investigated in male rats. A total extract of Boswellia papyrifera (300 mg/kg) was administered every eight hours to three groups of rats by gavage for 1, 2 and 4 weeks. In a separate set of experiments, three doses of a fraction of the extract, called the boswellic acids (100, 200 and 300 mg/kg) were administered by gavage to three groups of rats three times a day for 2 weeks. Following these applications, animals were trained for 4 days. Behavioral testing for evaluation of spatial memory retention was performed 48 h after completion of training. Boswellia papyrifera extracts and boswellic acids caused a significant reduction in escape latency and distance traveled but had no influence on swimming speed. These findings provide evidence that Boswellia papyrifera extracts affect spatial memory retention irrespective of the treatment period. In addition our data show that systemic administration of the boswellic acids fraction enhanced spatial memory retention in a dose-dependent manner. These improving effects may be due to some extent to the interactions of these products with inflammatory mediators, neurotransmitter signaling cascades or protein kinase pathways in the brain.
Ramos, Juan M. J.
In a previous study we showed a temporally graded retrograde amnesia after hippocampal lesions when rats learned a spatial reference memory task in which two types of signals simultaneously indicated the goal arm (shape of the experimental room and extramaze landmarks). To investigate the effect that the navigational demands of the task have on…
Vuckovich, Joseph A.; Semel, Mara E.; Baxter, Mark G.
A recent study suggests that lesions to all major areas of the cholinergic basal forebrain in the rat (medial septum, horizontal limb of the diagonal band of Broca, and nucleus basalis magnocellularis) impair a spatial working memory task. However, this experiment used a surgical technique that may have damaged cerebellar Purkinje cells. The…
Wuhr, Peter; Biebl, Rupert
This study investigates the impact of working memory (WM) load on response conflicts arising from spatial (non) correspondence between irrelevant stimulus location and response location (Simon effect). The dominant view attributes the Simon effect to automatic processes of location-based response priming. The automaticity view predicts…
Wong, Ling M.; Riggins, Tracy; Harvey, Danielle; Cabaral, Margarita; Simon, Tony J.
Individuals with chromosome 22q11.2 deletion syndrome (22q11.2DS) have been shown to have impairments in processing spatiotemporal information. The authors examined whether children with 22q11.2DS exhibit impairments in spatial working memory performance due to these weaknesses, even when controlling for maintenance of attention. Children with…
Yamazaki, Kaoruko; Wakabayashi, Noriyuki; Kobayashi, Takuya; Suzuki, Tetsuya
The mechanism by which tooth loss accelerates spatial memory impairment is unknown. The purpose of this study was to test the hypothesis that tooth loss affects trkB-mRNA levels and leads to an accelerated decrease in the hippocampal cell density in rats. A radial maze was used to evaluate the spatial memory of male Wistar rats that were categorized based on the number of extracted molar teeth. Number of hippocampal pyramidal cells and the trkB-mRNA expressions in the amygdala, perirhinal cortex, thalamus, and the hippocampal CA1, CA3, and CA4 areas, were evaluated using molecular biological techniques. Seven weeks after tooth extraction, maze performance was significantly lower in each tooth loss group than in the control group, and the number of extracted teeth was inversely proportional to the induction of the trkB-mRNA and the hippocampal cell density. The average weight of rats increased by controlled feeding throughout the experiment without showing a significant difference between the control and experimental groups. The results indicated that, in rats, the spatial memory-linked trkB-mRNA was reduced in association with the tooth loss; this supports the hypothesis and suggests that teeth have a role in the prevention of spatial memory impairment.
Guidi, Michael; Rani, Asha; Karic, Semir; Severance, Barrett; Kumar, Ashok; Foster, Thomas C.
A decrease in N-methyl-D-aspartate receptor (NMDAR) function is associated with age-related cognitive impairments. However, NMDAR antagonists are prescribed for cognitive decline associated with age-related neurodegenerative disease, raising questions as to the role of NMDAR activity in cognitive function during aging. The current studies examined effects of NMDAR blockade on cognitive task that are sensitive to aging. Young and middle-age rats were trained on the five-choice serial reaction time task (5-CSRTT) and challenged with MK-801 (0.025, 0.05, and 0.1 mg/kg or vehicle). Attention deficits were apparent in middle-age and performance of young and middle-age rats was enhanced for low doses of MK-801 (0.025 and 0.05). The beneficial effects on attention were reversed by the highest dose of MK-801. Older animals exhibited a delay-dependent impairment of episodic spatial memory examined on a delayed-matching to place water maze task. Similarly, a low dose of MK-801 (0.05 mg/kg) impaired performance with increasing delay and aged animals were more susceptible to disruption by NMDAR blockade. Despite MK-801 impairment of episodic spatial memory, MK-801 had minimal effects on spatial reference memory. Our results confirm that NMDARs contribute to rapidly acquired and flexible spatial memory and support the idea that a decline in NMDAR function contributes to the age-related impairments in cognition. PMID:26234588
Holden, Mark P.; Curby, Kim M.; Newcombe, Nora S.; Shipley, Thomas F.
Memories for spatial locations often show systematic errors toward the central value of the surrounding region. This bias has been explained using a Bayesian model in which fine-grained and categorical information are combined (Huttenlocher, Hedges, & Duncan, 1991). However, experiments testing this model have largely used locations contained in…
Pol-Bodetto, Sarah; Jeltsch-David, Hélène; Lecourtier, Lucas; Rusnac, Nathalia; Mam-Lam-Fook, Célia; Cosquer, Brigitte; Geiger, Karin; Cassel, Jean-Christophe
To explore spatial cognition in rodents, research uses maze tasks, which differ in complexity, number of goals and pathways, behavioural flexibility, memory duration, but also in the experimenter's control over the strategy developed to reach a goal (e.g., allocentric vs. egocentric). This study aimed at validating a novel spatial memory test: the double-H maze test. The transparent device made of an alley with two opposite arms at each extremity and two in its centre is flooded. An escape platform is submerged in one arm. For experiments 1-3, rats were released in unpredictable sequences from one of both central arms to favour an allocentric approach of the task. Experiment 1 (3 trials/day over 6 days) demonstrated classical learning curves and evidence for recent and nondegraded remote memory performance. Experiment 2 (2 days, 3 trials/day) showed a dose-dependent alteration of task acquisition/consolidation by muscarinic or NMDA receptor blockade; these drug effects vanished with sustained training (experiment 3; 4 days, 3 trials/day). Experiment 4 oriented rats towards a procedural (egocentric) approach of the task. Memory was tested in a misleading probe trial. Most rats immediately switched from response learning-based to place learning-based behaviour, but only when their initial view on environmental cues markedly differed between training and probe trials. Because this simple task enables the formation of a relatively stable memory trace, it could be particularly adapted to study consolidation processes at a system level or/and the interplay between procedural and declarative-like memory systems.
Burke, Hanna M; Robinson, Cristina M; Wentz, Bethany; McKay, Jerel; Dexter, Kyle W; Pisansky, Julia M; Talbot, Jeffery N; Zoladz, Phillip R
It has been suggested that cognitive impairments exhibited by people with post-traumatic stress disorder (PTSD) result from intrusive, flashback memories transiently interfering with ongoing cognitive processing. Researchers have further speculated that females are more susceptible to developing PTSD because they form stronger traumatic memories than males, hence females may be more sensitive to the negative effects of intrusive memories on cognition. We have examined how the reminder of a naturalistic stress experience would affect rat spatial memory and if sex was a contributing factor to such effects. Male and female Sprague-Dawley rats were exposed, without contact, to an adult female cat for 30 min. Five weeks later, the rats were trained to locate a hidden platform in the radial-arm water maze and given a single long-term memory test trial 24 h later. Before long-term memory testing, the rats were given a 30-min reminder of the cat exposure experienced 5 weeks earlier. The results indicated that the stress reminder impaired spatial memory in the female rats only. Control manipulations revealed that this effect was not attributable to the original cat exposure adversely impacting learning that occurred 5 weeks later, or to merely exposing rats to a novel environment or predator-related cues immediately before testing. These findings provide evidence that the reminder of a naturalistic stressful experience can impair cognitive processing in rats; moreover, since female rats were more susceptible to the memory-impairing effects of the stress reminder, the findings could lend insight into the existing sex differences in susceptibility to PTSD.
Leszczyński, Marcin; Wykowska, Agnieszka; Perez-Osorio, Jairo; Müller, Hermann J
Recalling information from visual short-term memory (VSTM) involves the same neural mechanisms as attending to an actually perceived scene. In particular, retrieval from VSTM has been associated with orienting of visual attention towards a location within a spatially-organized memory representation. However, an open question concerns whether spatial attention is also recruited during VSTM retrieval even when performing the task does not require access to spatial coordinates of items in the memorized scene. The present study combined a visual search task with a modified, delayed central probe protocol, together with EEG analysis, to answer this question. We found a temporal contralateral negativity (TCN) elicited by a centrally presented go-signal which was spatially uninformative and featurally unrelated to the search target and informed participants only about a response key that they had to press to indicate a prepared target-present vs. -absent decision. This lateralization during VSTM retrieval (TCN) provides strong evidence of a shift of attention towards the target location in the memory representation, which occurred despite the fact that the present task required no spatial (or featural) information from the search to be encoded, maintained, and retrieved to produce the correct response and that the go-signal did not itself specify any information relating to the location and defining feature of the target.
Perez-Osorio, Jairo; Müller, Hermann J.
Recalling information from visual short-term memory (VSTM) involves the same neural mechanisms as attending to an actually perceived scene. In particular, retrieval from VSTM has been associated with orienting of visual attention towards a location within a spatially-organized memory representation. However, an open question concerns whether spatial attention is also recruited during VSTM retrieval even when performing the task does not require access to spatial coordinates of items in the memorized scene. The present study combined a visual search task with a modified, delayed central probe protocol, together with EEG analysis, to answer this question. We found a temporal contralateral negativity (TCN) elicited by a centrally presented go-signal which was spatially uninformative and featurally unrelated to the search target and informed participants only about a response key that they had to press to indicate a prepared target-present vs. -absent decision. This lateralization during VSTM retrieval (TCN) provides strong evidence of a shift of attention towards the target location in the memory representation, which occurred despite the fact that the present task required no spatial (or featural) information from the search to be encoded, maintained, and retrieved to produce the correct response and that the go-signal did not itself specify any information relating to the location and defining feature of the target. PMID:24386295
Mammarella, Irene C.; Meneghetti, Chiara; Pazzaglia, Francesca; Cornoldi, Cesare
The present study investigated the difficulties encountered by children with non-verbal learning disability (NLD) and reading disability (RD) when processing spatial information derived from descriptions, based on the assumption that both groups should find it more difficult than matched controls, but for different reasons, i.e., due to a memory encoding difficulty in cases of RD and to spatial information comprehension problems in cases of NLD. Spatial descriptions from both survey and route perspectives were presented to 9–12-year-old children divided into three groups: NLD (N = 12); RD (N = 12), and typically developing controls (TD; N = 15); then participants completed a sentence verification task and a memory for locations task. The sentence verification task was presented in two conditions: in one the children could refer to the text while answering the questions (i.e., text present condition), and in the other the text was withdrawn (i.e., text absent condition). Results showed that the RD group benefited from the text present condition, but was impaired to the same extent as the NLD group in the text absent condition, suggesting that the NLD children’s difficulty is due mainly to their poor comprehension of spatial descriptions, while the RD children’s difficulty is due more to a memory encoding problem. These results are discussed in terms of their implications in the neuropsychological profiles of children with NLD or RD, and the processes involved in spatial descriptions. PMID:25610417
Tyler, Anna L; Mahoney, J Matthew; Richard, Gregory R; Holmes, Gregory L; Lenck-Santini, Pierre-Pascal; Scott, Rod C
Status epilepticus (SE) is a common neurological emergency, which has been associated with subsequent cognitive impairments. Neuronal death in hippocampal CA1 is thought to be an important mechanism of these impairments. However, it is also possible that functional interactions between surviving neurons are important. In this study we recorded in vivo single-unit activity in the CA1 hippocampal region of rats while they performed a spatial memory task. From these data we constructed functional networks describing pyramidal cell interactions. To build the networks, we used maximum entropy algorithms previously applied only to in vitro data. We show that several months following SE pyramidal neurons display excessive neuronal synchrony and less neuronal reactivation during rest compared with those in healthy controls. Both effects predict rat performance in a spatial memory task. These results provide a physiological mechanism for SE-induced cognitive impairment and highlight the importance of the systems-level perspective in investigating spatial cognition.
Brown, Louise A
Working memory is vulnerable to age-related decline, but there is debate regarding the age-sensitivity of different forms of spatial-sequential working memory task, depending on their passive or active nature. The functional architecture of spatial working memory was therefore explored in younger (18-40 years) and older (64-85 years) adults, using passive and active recall tasks. Spatial working memory was assessed using a modified version of the Spatial Span subtest of the Wechsler Memory Scale - Third Edition (WMS-III; Wechsler, 1998). Across both age groups, the effects of interference (control, visual, or spatial), and recall type (forward and backward), were investigated. There was a clear effect of age group, with younger adults demonstrating a larger spatial working memory capacity than the older adults overall. There was also a specific effect of interference, with the spatial interference task (spatial tapping) reliably reducing performance relative to both the control and visual interference (dynamic visual noise) conditions in both age groups and both recall types. This suggests that younger and older adults have similar dependence upon active spatial rehearsal, and that both forward and backward recall require this processing capacity. Linear regression analyses were then carried out within each age group, to assess the predictors of performance in each recall format (forward and backward). Specifically the backward recall task was significantly predicted by age, within both the younger and older adult groups. This finding supports previous literature showing lifespan linear declines in spatial-sequential working memory, and in working memory tasks from other domains, but contrasts with previous evidence that backward spatial span is no more sensitive to aging than forward span. The study suggests that backward spatial span is indeed more processing-intensive than forward span, even when both tasks include a retention period, and that age predicts
Brown, Louise A.
Working memory is vulnerable to age-related decline, but there is debate regarding the age-sensitivity of different forms of spatial-sequential working memory task, depending on their passive or active nature. The functional architecture of spatial working memory was therefore explored in younger (18–40 years) and older (64–85 years) adults, using passive and active recall tasks. Spatial working memory was assessed using a modified version of the Spatial Span subtest of the Wechsler Memory Scale – Third Edition (WMS-III; Wechsler, 1998). Across both age groups, the effects of interference (control, visual, or spatial), and recall type (forward and backward), were investigated. There was a clear effect of age group, with younger adults demonstrating a larger spatial working memory capacity than the older adults overall. There was also a specific effect of interference, with the spatial interference task (spatial tapping) reliably reducing performance relative to both the control and visual interference (dynamic visual noise) conditions in both age groups and both recall types. This suggests that younger and older adults have similar dependence upon active spatial rehearsal, and that both forward and backward recall require this processing capacity. Linear regression analyses were then carried out within each age group, to assess the predictors of performance in each recall format (forward and backward). Specifically the backward recall task was significantly predicted by age, within both the younger and older adult groups. This finding supports previous literature showing lifespan linear declines in spatial-sequential working memory, and in working memory tasks from other domains, but contrasts with previous evidence that backward spatial span is no more sensitive to aging than forward span. The study suggests that backward spatial span is indeed more processing-intensive than forward span, even when both tasks include a retention period, and that age predicts
Barra, Julien; Laou, Laetitia; Poline, Jean-Baptiste; Lebihan, Denis; Berthoz, Alain
Perspective (route or survey) during the encoding of spatial information can influence recall and navigation performance. In our experiment we investigated a third type of perspective, which is a slanted view. This slanted perspective is a compromise between route and survey perspectives, offering both information about landmarks as in route perspective and geometric information as in survey perspective. We hypothesized that the use of slanted perspective would allow the brain to use either egocentric or allocentric strategies during storage and recall. Twenty-six subjects were scanned (3-Tesla fMRI) during the encoding of a path (40-s navigation movie within a virtual city). They were given the task of encoding a segment of travel in the virtual city and of subsequent shortcut-finding for each perspective: route, slanted and survey. The analysis of the behavioral data revealed that perspective influenced response accuracy, with significantly more correct responses for slanted and survey perspectives than for route perspective. Comparisons of brain activation with route, slanted, and survey perspectives suggested that slanted and survey perspectives share common brain activity in the left lingual and fusiform gyri and lead to very similar behavioral performance. Slanted perspective was also associated with similar activation to route perspective during encoding in the right middle occipital gyrus. Furthermore, slanted perspective induced intermediate patterns of activation (in between route and survey) in some brain areas, such as the right lingual and fusiform gyri. Our results suggest that the slanted perspective may be considered as a hybrid perspective. This result offers the first empirical support for the choice to present the slanted perspective in many navigational aids. PMID:23209583
Chow, Carmen; Epp, Jonathan R; Lieblich, Stephanie E; Barha, Cindy K; Galea, Liisa A M
Adult hippocampal neurogenesis is often associated with hippocampus-dependent learning and memory. Throughout a new neuron's development, it is differentially sensitive to factors that can influence its survival and functionality. Previous research shows that spatial training that occurred 6-10 days after an injection of the DNA synthesis marker, bromodeoxyuridine (BrdU), increased cell survival in male rats. Because sex differences in spatial cognition and hippocampal neurogenesis have been reported, it is unclear whether spatial training would influence hippocampal neurogenesis in the same way in males and females. Therefore, this study examined sex differences in hippocampal neurogenesis following training in a spatial task. Male and female rats were trained in the spatial or cued version of the Morris water maze 6-10 days after one injection of BrdU (200mg/kg). Twenty days following BrdU injection, all animals were given a probe trial and perfused. Males performed better in the spatial, but not cue, task than females. Spatial training increased BrdU-labeled cells relative to cue training only in males, but both males and females showed greater activation of new cells (BrdU co-labeled with immediate early gene product zif268) after spatial training compared to cue training. Furthermore, performance during spatial training was positively correlated with cell activation in females but not males. This study shows that while spatial training differentially regulates hippocampal neurogenesis in males and females, the activity of new neurons in response to spatial memory retrieval is similar. These findings highlight the importance of sex on neural plasticity and cognition.
Meier, Timothy B; Nair, Veena A; Meyerand, Mary E; Birn, Rasmus M; Prabhakaran, Vivek
In this study, we investigated the neural correlates of age-related differences in the binding of verbal and spatial information utilizing event-related working memory tasks. Twenty-one right handed younger adults and twenty-one right handed older adults performed two versions of a dual task of verbal and spatial working memory. In the unbound dual task version letters and locations were presented simultaneously in separate locations, while in the bound dual task version each letter was paired with a specific location. In order to identify binding-specific differences, mixed-effects ANOVAs were run with the interaction of age and task as the effect of interest. Although older adults performed worse in the bound task than younger adults, there was no significant interaction between task and age on working memory performance. However, interactions of age and task were observed in brain activity analyses. Older adults did not display the greater unbound than bound task activity that younger adults did at the encoding phase in bilateral inferior parietal lobule, right putamen, and globus pallidus as well as at the maintenance phase in the cerebellum. We conclude that the binding of letters and locations in working memory is not as efficient in older adults as it is in younger adults, possibly due to the decline of cognitive control processes that are specific to working memory binding.
Basu, Amrita; McFarlane, Hewlet G; Kopchick, John J
Growth hormone (GH) has a significant influence on cognitive performance in humans and other mammals. To understand the influence of altered GH action on cognition, we assessed spatial learning and memory using a Barnes maze (BM) comparing twelve-month old, male, bovine GH (bGH) and GH receptor antagonist (GHA) transgenic mice and their corresponding wild type (WT) littermates. During the acquisition training period in the BM, bGH mice showed increased latency, traveled longer path lengths and made more errors to reach the target than WT mice indicating significantly poorer learning. Short-term memory (STM) and long-term memory (LTM) trials showed significantly suppressed memory retention in bGH mice when compared to the WT group. Conversely, GHA mice showed significantly better learning parameters (latency, path length and errors) and increased use of an efficient search strategy than WT mice. Our study indicates a negative impact of GH excess and a beneficial effect of the inhibition of GH action on spatial learning and memory and, therefore, cognitive performance in male mice. Further research to elucidate GH's role in brain function will facilitate identifying therapeutic applications of GH or GHA for neuropathological and neurodegenerative conditions.
Olver, James S; Pinney, Myra; Maruff, Paul; Norman, Trevor R
Few studies have investigated the effect of an acute psychosocial stress paradigm on impaired attention and working memory in humans. Further, the duration of any stress-related cognitive impairment remains unclear. The aim of this study was to examine the effect of an acute psychosocial stress paradigm, the Trier Social Stress, on cognitive function in healthy volunteers. Twenty-three healthy male and female subjects were exposed to an acute psychosocial stress task. Physiological measures (salivary cortisol, heart rate and blood pressure) and subjective stress ratings were measured at baseline, in anticipation of stress, immediately post-stress and after a period of rest. A neuropsychological test battery including spatial working memory and verbal memory was administered at each time point. Acute psychosocial stress produced significant increases in cardiovascular and subjective measures in the anticipatory and post-stress period, which recovered to baseline after rest. Salivary cortisol steadily declined over the testing period. Acute psychosocial stress impaired delayed verbal recall, attention and spatial working memory. Attention remained impaired, and delayed verbal recall continued to decline after rest. Acute psychosocial stress is associated with an impairment of a broad range of cognitive functions in humans and with prolonged abnormalities in attention and memory.
Wiener, J M; Ehbauer, N N; Mallot, H A
For large numbers of targets, path planning is a complex and computationally expensive task. Humans, however, usually solve such tasks quickly and efficiently. We present experiments studying human path planning performance and the cognitive processes and heuristics involved. Twenty-five places were arranged on a regular grid in a large room. Participants were repeatedly asked to solve traveling salesman problems (TSP), i.e., to find the shortest closed loop connecting a start location with multiple target locations. In Experiment 1, we tested whether humans employed the nearest neighbor (NN) strategy when solving the TSP. Results showed that subjects outperform the NN-strategy, suggesting that it is not sufficient to explain human route planning behavior. As a second possible strategy we tested a hierarchical planning heuristic in Experiment 2, demonstrating that participants first plan a coarse route on the region level that is refined during navigation. To test for the relevance of spatial working memory (SWM) and spatial long-term memory (LTM) for planning performance and the planning heuristics applied, we varied the memory demands between conditions in Experiment 2. In one condition the target locations were directly marked, such that no memory was required; a second condition required participants to memorize the target locations during path planning (SWM); in a third condition, additionally, the locations of targets had to retrieved from LTM (SWM and LTM). Results showed that navigation performance decreased with increasing memory demands while the dependence on the hierarchical planning heuristic increased.
Churchwell, John C; Kesner, Raymond P
Memory processes may be independent, compete, operate in parallel, or interact. In accordance with this view, behavioral studies suggest that the hippocampus (HPC) and prefrontal cortex (PFC) may act as an integrated circuit during performance of tasks that require working memory over longer delays, whereas during short delays the HPC and PFC may operate in parallel or have completely dissociable functions. In the present investigation we tested rats in a spatial delayed non-match to sample working memory task using short and long time delays to evaluate the hypothesis that intermediate CA1 region of the HPC (iCA1) and medial PFC (mPFC) interact and operate in parallel under different temporal working memory constraints. In order to assess the functional role of these structures, we used an inactivation strategy in which each subject received bilateral chronic cannula implantation of the iCA1 and mPFC, allowing us to perform bilateral, contralateral, ipsilateral, and combined bilateral inactivation of structures and structure pairs within each subject. This novel approach allowed us to test for circuit-level systems interactions, as well as independent parallel processing, while we simultaneously parametrically manipulated the temporal dimension of the task. The current results suggest that, at longer delays, iCA1 and mPFC interact to coordinate retrospective and prospective memory processes in anticipation of obtaining a remote goal, whereas at short delays either structure may independently represent spatial information sufficient to successfully complete the task.
Trofimiuk, Emil; Holownia, Adam; Braszko, Jan J
St. John's wort (Hypericum perforatum) is one of the leading psychotherapeutic phytomedicines. Beneficial effects of this herb in the treatment of mild to moderate depression are well known. In this study we tested a hypothesis that St. John's wort alleviates age-related memory impairments by increasing the levels of cyclic adenosine 3', 5'-monophosphate response element binding protein (CREB) and phosphorylated CREB (pCREB) in hippocampus. Middleaged rats (18 month-old) displayed a decline in the acquisition of spatial working memory (p < 0.001) in the Morris water maze (MWM). Chronic administration of Hypericum perforatum (HP) (350 mg/kg for 21 days), potently and significantly improved the processing of spatial information in the aged rats (p < 0.001). Also the herb increased the levels of pCREB in the aged rat's hippocampus (p < 0.01) as measured by western immunoblotting. Aging caused significant locomotor impairments as tested in the open field (p < 0.001) but not in the MWM test. However, these were unaffected by treatment with HP. Thus, this study indicates that St. John's wort effectively prevents aging-induced deterioration of spatial memory in 18 month-old rats, possibly by the activation of CREB regulated genes associated with memory formation. It appears that mechanism is probably inactive in young rats.
Hashemi Nosrat Abadi, T; Vaghef, L; Babri, S; Mahmood-Alilo, M; Beirami, M
Chronic ethanol consumption is often accompanied by numerous cognitive deficits and may lead to long-lasting impairments in spatial learning and memory. The aim of the present study was to evaluate the therapeutic potential of regular treadmill exercise on hippocampal-dependent memory in ethanol-treated rats. Spatial memory was tested in a Morris Water Maze task. Adult male Wistar rats were exposed to ethanol (4 g/kg, 20% v/v for 4 weeks) and effects of three exercise protocols (pre-ethanol, post-ethanol and pre-to-post-ethanol treatment) were examined. Results showed that ethanol exposure resulted in longer escape latencies during the acquisition phase of the Morris Water Maze task. Moreover, all three exercise protocols significantly decreased the latency to locate the hidden platform. During the probe trial, ethanol led to decreased time spent in the target quadrant. In contrast, performance on the probe trial was significantly better in the rats that had done the post- and pre-to-post-ethanol, but not pre-ethanol, exercises. These findings suggest that treadmill running can attenuate the adverse effects of chronic ethanol exposure on spatial memory, and may serve as a non-pharmacological alcohol abuse treatment.
Sun, Huaying; Mao, Yu; Wang, Jianhong; Ma, Yuanye
The beta-adrenergic system has been suggested to be involved in novelty detection and memory modulation. The present study aimed to investigate the role of beta-adrenergic receptors on novelty-based spatial recognition memory and exploratory behavior in mice using Y-maze test and open-field respectively. Mice were injected with three doses of beta-adrenergic receptor antagonist, propranolol (2, 10 and 20 mg/kg) or saline at three different time points (15 min prior to training, immediately after training and 15 min before test). The results showed that higher doses of propranolol (10 and 20 mg/kg) given before the training trial impaired spatial recognition memory while those injected at other two time points did not. A detailed analysis of exploratory behavior in open-field showed that lower dose (2 mg/kg) of propranolol reduced exploratory behavior of mice. Our findings indicate that higher dose of propranolol can impair acquisition of spatial information in the Y-maze without altering locomotion, suggesting that the beta-adrenergic system may be involved in modulating memory processes at the time of learning.
Patarroyo, William E; García-Perez, Milady; Lamprea, Marisol; Múnera, Alejandro; Troncoso, Julieta
This research was aimed at establishing how the absence of active whisking in rats affects acquisition and recovery of spatial memory. The mystacial vibrissae were irreversibly paralyzed by cutting the facial nerve's mandibular and buccal branches bilaterally in the facial nerve lesion group (N=14); control animals were submitted to sham-surgery (N=15). Sham-operated (N=11) and facial nerve-lesioned (N=10) animals were trained (one session, eight acquisition trials) and tested 24h later in a circular Barnes maze. It was found that facial nerve lesioned-animals adequately acquired the spatial task, but had impaired recovery of it when tested 24h after training as compared to control ones. Plasma corticosterone levels were measured after memory testing in four randomly chosen animals of each trained group and after a single training trial in the maze in additional facial nerve-lesioned (N=4) and sham-operated animals (N=4). Significant differences respecting the elevation of corticosterone concentration after either a single training trial or memory testing indicated that stress response was enhanced in facial nerve-lesioned animals as compared to control ones. Increased corticosterone levels during training and testing might have elicited the observed whisker paralysis-induced spatial memory retrieval impairment.
Chen, Yan-Chu; Hsu, Wei-Lun; Ma, Yun-Li; Tai, Derek J C; Lee, Eminy H Y
cAMP-responsive element binding protein (CREB) phosphorylation and signaling plays an important role in long-term memory formation, but other posttranslational modifications of CREB are less known. Here, we found that CREB1Δ, the short isoform of CREB, could be sumoylated by the small ubiquitin-like modifier (SUMO) E3 ligase protein inhibitor of activated STAT1 (PIAS1) at Lys271 and Lys290 and PIAS1 SUMOylation of CREB1Δ increased the expression level of CREB1Δ. CREB1Δ could also be sumoylated by other PIAS family proteins, but not by the E3 ligases RanBP2 and Pc2 or by the E2 ligase Ubc9. Furthermore, water maze training increased the level of endogenous CREB SUMOylation in rat CA1 neurons determined by in vitro SUMOylation assay, but this effect was not observed in other brain areas. Moreover, transduction of Lenti-CREBWT to rat CA1 area facilitated, whereas transduction of Lenti-CREB double sumo-mutant (CREBK271RK290R) impaired, spatial learning and memory performance. Transduction of Lenti-CREBWT-SUMO1 fusion vector to rat CA1 area showed a more significant effect in enhancing spatial learning and memory and CREB SUMOylation. Lenti-CREBWT transduction increased, whereas Lenti-CREBK271RK290R transduction decreased, CREB DNA binding to the brain-derived neurotrophic factor (bdnf) promoter and decreased bdnf mRNA expression. Knock-down of PIAS1 expression in CA1 area by PIAS1 siRNA transfection impaired spatial learning and memory and decreased endogenous CREB SUMOylation. In addition, CREB SUMOylation was CREB phosphorylation dependent and lasted longer. Therefore, CREB phosphorylation may be responsible for signal transduction during the early phase of long-term memory formation, whereas CREB SUMOylation sustains long-term memory.
Slotnick, Scott D; Thakral, Preston P
Long-term memory can be based on general familiarity or detailed recollection. Although familiarity is thought to be a continuous/graded process, the nature of recollection is currently under debate. In the present functional MRI spatial source memory study, we evaluated the pattern of activity in the hippocampus to assess whether this region operates in a threshold/all-or-none or a continuous manner during recollection. During the study phase, abstract shapes were presented to the left or right of fixation. During the test phase, old and new shapes were presented at fixation, and participants classified each shape as old-left, old-right, or new, followed by a sure-unsure confidence rating. Accurate spatial memory for old-left shapes produced a single activation in the left hippocampus. The corresponding event-related activation profile revealed a threshold above which old-left-sure responses produced positive activity for old-left but not old-right shapes. This hippocampal activation profile was used to generate a source memory receiver operating characteristic that was adequately fit by a threshold model of recollection but was not adequately fit by a continuous model of recollection. By contrast, there was no evidence of a threshold in the behavioral response profile, which is consistent with previous behavioral source memory receiver operating characteristic results indicating that recollection is a continuous process. The present results indicate that the hippocampus can operate in a threshold manner during spatial source memory and further suggest that this discrete signal is transformed into a continuous process through the operation of other brain regions that also contribute to behavioral performance.
Working memory is a dynamic neural system that includes processes for temporarily maintaining and processing information. Working memory plays a significant role in a variety of cognitive functions, such as thinking, reasoning, decision-making, and language comprehension. Although the prefrontal cortex (PFC) is known to play an important role in working memory, several lines of evidence indicate that the thalamic mediodorsal nucleus (MD) also participates in this process. While monkeys perform spatial working memory tasks, MD neurons exhibit directionally selective delay-period activity, which is considered to be a neural correlate for the temporary maintenance of information in PFC neurons. Studies have also shown that, while most MD neurons maintain prospective motor information, some maintain retrospective sensory information. Thus, the MD plays a greater role in prospective motor aspects of working memory processes than the PFC, which participates more in retrospective aspects. For the performance of spatial working memory tasks, the information provided by a sensory cue needs to be transformed into motor information to give an appropriate response. A population vector analysis using neural activities revealed that, although the transformation of sensory-to-motor information occurred during the delay period in both the PFC and the MD, PFC activities maintained sensory information until the late phase of the delay period, while MD activities initially represented sensory information but then started to represent motor information in the earlier phase of the delay period. These results indicate that long-range neural interactions supported by reciprocal connections between the MD and the PFC could play an important role in the transformation of maintained information in working memory processes.
Katshu, Mohammad Zia Ul Haq; d'Avossa, Giovanni
While sensory processes are tuned to particular features, such as an object's specific location, color or orientation, visual working memory (vWM) is assumed to store information using representations, which generalize over a feature dimension. Additionally, current vWM models presume that different features or objects are stored independently. On the other hand, configurational effects, when observed, are supposed to mainly reflect encoding strategies. We show that the location of the target, relative to the display center and boundaries, and overall memory load influenced recall precision, indicating that, like sensory processes, capacity limited vWM resources are spatially tuned. When recalling one of three memory items the target distance from the display center was overestimated, similar to the error when only one item was memorized, but its distance from the memory items' average position was underestimated, showing that not only individual memory items' position, but also the global configuration of the memory array may be stored. Finally, presenting the non-target items at recall, consequently providing landmarks and configurational information, improved precision and accuracy of target recall. Similarly, when the non-target items were translated at recall, relative to their position in the initial display, a parallel displacement of the recalled target was observed. These findings suggest that fine-grained spatial information in vWM is represented in local maps whose resolution varies with distance from landmarks, such as the display center, while coarse representations are used to store the memory array configuration. Both these representations are updated at the time of recall. PMID:25259601
Cassilhas, R C; Lee, K S; Fernandes, J; Oliveira, M G M; Tufik, S; Meeusen, R; de Mello, M T
A growing body of scientific evidence indicates that exercise has a positive impact on human health, including neurological health. Aerobic exercise, which is supposed to enhance cardiovascular functions and metabolism, also induces neurotrophic factors that affect hippocampal neurons, thereby improving spatial learning and memory. Alternatively, little is known about the effect of resistance exercise on hippocampus-dependent memory, although this type of exercise is increasingly recommended to improve muscle strength and bone density and to prevent age-related disabilities. Therefore, we evaluated the effects of resistance training on spatial memory and the signaling pathways of brain-derived neurotrophic factor (BDNF) and insulin-like growth factor 1 (IGF-1), comparing these effects with those of aerobic exercise. Adult male Wistar rats underwent 8 weeks of aerobic training on a treadmill (AERO group) or resistance training on a vertical ladder (RES group). Control and sham groups were also included. After the training period, both AERO and RES groups showed improved learning and spatial memory in a similar manner. However, both groups presented distinct signaling pathways. Although the AERO group showed increased level of IGF-1, BDNF, TrkB, and β-CaMKII (calcium/calmodulin-dependent kinase II) in the hippocampus, the RES group showed an induction of peripheral and hippocampal IGF-1 with concomitant activation of receptor for IGF-1 (IGF-1R) and AKT in the hippocampus. These distinct pathways culminated in an increase of synapsin 1 and synaptophysin expression in both groups. These findings demonstrated that both aerobic and resistance exercise can employ divergent molecular mechanisms but achieve similar results on learning and spatial memory.
Croston, Rebecca; Branch, Carrie L; Kozlovsky, Dovid Y; Roth, Timothy C; LaDage, Lara D; Freas, Cody A; Pravosudov, Vladimir V
Harsh environments and severe winters have been hypothesized to favor improvement of the cognitive abilities necessary for successful foraging. Geographic variation in winter climate, then, is likely associated with differences in selection pressures on cognitive ability, which could lead to evolutionary changes in cognition and its neural mechanisms, assuming that variation in these traits is heritable. Here, we focus on two species of food-caching chickadees (genus Poecile), which rely on stored food for survival over winter and require the use of spatial memory to recover their stores. These species also exhibit extensive climate-related population level variation in spatial memory and the hippocampus, including volume, the total number and size of neurons, and adults' rates of neurogenesis. Such variation could be driven by several mechanisms within the context of natural selection, including independent, population-specific selection (local adaptation), environment experience-based plasticity, developmental differences, and/or epigenetic differences. Extensive data on cognition, brain morphology, and behavior in multiple populations of these two species of chickadees along longitudinal, latitudinal, and elevational gradients in winter climate are most consistent with the hypothesis that natural selection drives the evolution of local adaptations associated with spatial memory differences among populations. Conversely, there is little support for the hypotheses that environment-induced plasticity or developmental differences are the main causes of population differences across climatic gradients. Available data on epigenetic modifications of memory ability are also inconsistent with the observed patterns of population variation, with birds living in more stressful and harsher environments having better spatial memory associated with a larger hippocampus and a larger number of hippocampal neurons. Overall, the existing data are most consistent with the
Majkutewicz, Irena; Kurowska, Ewelina; Podlacha, Magdalena; Myślińska, Dorota; Grembecka, Beata; Ruciński, Jan; Plucińska, Karolina; Jerzemowska, Grażyna; Wrona, Danuta
Intracerebroventricular (ICV) injection of streptozotocin (STZ) is a widely-accepted animal model of sporadic Alzheimer's disease (sAD). The present study evaluated the ability of dimethyl fumarate (DMF), an agent with antioxidant and anti-inflammatory properties, to prevent spatial memory impairments and hippocampal neurodegeneration mediated by ICV injection of STZ in 4-month-old rats. Rodent chow containing DMF (0.4%) or standard rodent chow was made available on day 0. Rat body weight and food intake were measured daily for whole the experiment (21days). STZ or vehicle (SHAM) ICV injections were performed on days 2 and 4. Spatial reference and working memory were evaluated using the Morris water maze on days 14-21. Cells containing Fluoro-Jade B (neurodegeneration marker), IL-6, IL-10 were quantified in the hippocampus and choline acetyltransferase (ChAT) in the basal forebrain. The disruption of spatial memory and a high density of hippocampal CA1-3 cells labeled with Fluoro-Jade B or containing IL-6 or IL-10 were observed in the STZ group but not in the STZ+DMF group, as compared to the SHAM or SHAM+DMF groups. STZ vs. STZ+DMF differences were found: worse reference memory acquisition, fewer ChAT-positive neurons in the medial septum (Ch1), more Fluoro-Jade-positive CA1 hippocampal cells in STZ rats. DMF therapy in a rodent model of sAD prevented the disruption of spatial reference and working memory, loss of Ch1 cholinergic cells and hippocampal neurodegeneration as well as the induction of IL-6 and IL-10 in CA1. These beneficial cognitive and molecular effects validate the anti-inflammatory and neuroprotective properties of DMF in the hippocampus.
Thangarajan, Rajesh; Rai, Kiranmai. S.; Gopalakrishnan, Sivakumar; Perumal, Vivek
Background Gestational infections induced inflammation (GIII) is a cause of various postnatal neurological deficits in developing countries. Such intra uterine insults could result in persistent learning-memory disabilities. There are no studies elucidating the efficacy of adolescence exercise on spatial learning- memory abilities of young adult rats pre-exposed to inflammatory insult during fetal life. Aims and Objectives The present study addresses the efficacy of physical (running) exercise during adolescent period in attenuating spatial memory deficits induced by exposure to GIII in rats. Materials and Methods Pregnant Wistar dams were randomly divided into control and lipopolysaccharide (LPS) groups, injected intra peritoneally (i.p) with saline (0.5ml) or lipopolysaccharide (LPS) (0.5mg/kg) on alternate days from gestation day 14 (GD 14) till delivery. After parturition, pups were divided into 3 groups (n=6/group) a) Sham control and LPS group divided into 2 subgroups- b) LPS and c) LPS exercise group. Running exercise was given only to LPS exercise group during postnatal days (PNDs) 30 to 60 (15min/day). Spatial learning and memory performance was assessed by Morris water maze test (MWM), on postnatal day 61 to 67 in all groups. Results Young rats pre-exposed to GIII and subjected to running exercise through juvenile period displayed significant decrease in latency to reach escape platform and spent significant duration in target quadrant in MWM test, compared to age matched LPS group. Results of the current study demonstrated that exercise through juvenile/adolescent period effectively mitigates gestational inflammation-induced cognitive deficits in young adult rats. Conclusion Inflammation during gestation impairs offspring’s spatial memory and learning abilities. Whereas, early postnatal physical exercise attenuates, to higher extent, cognitive impairment resulted from exposure to LPS induced inflammation during intrauterine growth period. PMID:26266117
Neely, Kristina A; Tessmer, Ayla; Binsted, Gordon; Heath, Matthew
The location of an object in peripersonal space can be represented with respect to our body (i.e., egocentric frame of reference) or relative to contextual features and other objects (i.e., allocentric frame of reference). In the current study, we sought to determine whether the frame, or frames, of visual reference supporting motor output is influenced by reach trajectories structured to maximize visual feedback utilization (i.e., controlled online) or structured largely in advance of movement onset via central planning mechanisms (i.e., controlled offline). Reaches were directed to a target embedded in a pictorial illusion (the induced Roelofs effect: IRE) and advanced knowledge of visual feedback was manipulated to influence the nature of reaching control as reported by Zelaznik et al. (J Mot Behav 15:217-236, 1983). When vision could not be predicted in advance of movement onset, trajectories showed primary evidence of an offline mode of control (even when vision was provided) and endpoints demonstrated amplified sensitivity to the illusory (i.e., allocentric) features of the IRE. In contrast, reaches performed with reliable visual feedback evidenced a primarily online mode of control and showed increased visuomotor resistance to the IRE. These findings suggest that the manner a reaching response is structured differentially influences the weighting of allocentric and egocentric visual information. More specifically, when visual feedback is unavailable or unpredictable, the weighting of allocentric visual information for the advanced planning of a reach trajectory is increased.
Jung, Jae Yup; McCormick, John; Gross, Miraca U. M.
This study developed and tested a new model of the forced choice dilemma (i.e., the belief held by some intellectually gifted students that they must choose between academic achievement and peer acceptance) that incorporates individual-level cultural orientation variables (i.e., vertical allocentrism and vertical idiocentrism). A survey that had…
Alexander, Gerianne M; Packard, Mark G; Peterson, Bradley S
Memory for object location relative both to veridical center (left versus right visual hemispace) and to eccentricity (central versus peripheral objects) was measured in 26 males and 25 females using the Silverman and Eals Location Memory Task. A subset of participants (17 males and 13 females) also completed a measure of implicit learning, the mirror-tracing task. No sex differences were observed in memory for object identities. Further, in both sexes, memory for object locations was better for peripherally located objects than for centrally located objects. In contrast to these similarities in female and male task performance, females but not males showed better recovery of object locations in the right compared to the left visual hemispace. Moreover, memory for object locations in the right hemispace was associated with mirror-tracing performance in women but not in men. Together, these data suggest that the processing of object features and object identification in the left cerebral hemisphere may include processing of spatial information that may contribute to superior object location memory in females relative to males.
Brunec, Iva K; Ozubko, Jason D; Barense, Morgan D; Moscovitch, Morris
Time and space represent two key aspects of episodic memories, forming the spatiotemporal context of events in a sequence. Little is known, however, about how temporal information, such as the duration and the order of particular events, are encoded into memory, and if it matters whether the memory representation is based on recollection or familiarity. To investigate this issue, we used a real world virtual reality navigation paradigm where periods of navigation were interspersed with pauses of different durations. Crucially, participants were able to reliably distinguish the durations of events that were subjectively "reexperienced" (i.e., recollected), but not of those that were familiar. This effect was not found in temporal order (ordinal) judgments. We also show that the active experience of the passage of time (holding down a key while waiting) moderately enhanced duration memory accuracy. Memory for event duration, therefore, appears to rely on the hippocampally supported ability to recollect or reexperience an event enabling the reinstatement of both its duration and its spatial context, to distinguish it from other events in a sequence. In contrast, ordinal memory appears to rely on familiarity and recollection to a similar extent.
Rossato, Janine I; Köhler, Cristiano A; Radiske, Andressa; Bevilaqua, Lia R M; Cammarota, Martín
Active memories can incorporate new information through reconsolidation. However, the notion that memory retrieval is necessary for reconsolidation has been recently challenged. Non-reinforced retrieval induces hippocampus and medial prefrontal cortex (mPFC)-dependent reconsolidation of spatial memory in the Morris water maze (MWM). We found that the effect of protein synthesis inhibition on this process is abolished when retrieval of the learned spatial preference is hindered through mPFC inactivation but not when it is blocked by deactivation of dorsal CA1. Our results do not fully agree with the hypothesis that retrieval is unneeded for reconsolidation. Instead, they support the idea that a hierarchic interaction between the hippocampus and the mPFC controls spatial memory in the MWM, and indicate that this cortex is sufficient to retrieve the information essential to reconsolidate the spatial memory trace, even when the hippocampus is inactivated.
Azzopardi, Erin; Ruettiger, Lukas; Ruth, Peter; Schmid, Susanne
Genetic variations in the large-conductance, voltage- and calcium activated potassium channels (BK channels) have been recently implicated in mental retardation, autism and schizophrenia which all come along with severe cognitive impairments. In the present study we investigate the effects of functional BK channel deletion on cognition using a genetic mouse model with a knock-out of the gene for the pore forming α-subunit of the channel. We tested the F1 generation of a hybrid SV129/C57BL6 mouse line in which the slo1 gene was deleted in both parent strains. We first evaluated hearing and motor function to establish the suitability of this model for cognitive testing. Auditory brain stem responses to click stimuli showed no threshold differences between knockout mice and their wild-type littermates. Despite of muscular tremor, reduced grip force, and impaired gait, knockout mice exhibited normal locomotion. These findings allowed for testing of sensorimotor gating using the acoustic startle reflex, as well as of working memory, spatial learning and memory in the Y-maze and the Morris water maze, respectively. Prepulse inhibition on the first day of testing was normal, but the knockout mice did not improve over the days of testing as their wild-type littermates did. Spontaneous alternation in the y-maze was normal as well, suggesting that the BK channel knock-out does not impair working memory. In the Morris water maze knock-out mice showed significantly slower acquisition of the task, but normal memory once the task was learned. Thus, we propose a crucial role of the BK channels in learning, but not in memory storage or recollection. PMID:24303038
Nelson, Michael E.
The role of spatial memory in the movement of animals through landscapes remains elusive. To examine spatial memory and home range affinity of White-tailed Deer (Odocoileus virginianus) in northeastern Minnesota during 1995–2007, I translocated 17 adult does with known home ranges to unfamiliar sites and radio-tracked them after their release. Twelve does wearing transmitting radio-collars returned to their home ranges. Death and collar expiration precluded determination of whether the remaining five does would have returned to home ranges. Three of five does wearing global positioning system collars traveled throughout hundreds of square kilometres, circling, backtracking, and returning to release sites, while two others exhibited directional movement for tens of kilometres. Four does that survived to parturition stopped traveling and moved at hourly rates similar to those of control does during the first three weeks of the typical fawn-rearing period, but continued traveling later. Their aberrant extensive travel before and after interruption by parturition suggests that they recognized they were in unfamiliar areas, demonstrating both their capacity and propensity to search for and occupy the familiar space of their individual home ranges. Their successful return to home ranges provided experimental evidence of spatial memory and further elucidated its pervasive role in White-tailed Deer spatial ecology.
Yi, Jee Hyun; Park, Hye Jin; Kim, Byeong C; Kim, Dong Hyun; Ryu, Jong Hoon
The hippocampus is a key region responsible for processing spatial information. However, the role of the hippocampus in non-spatial recognition memory is still controversial. In the present study, we performed hippocampal lesioning to address this controversy. The hippocampi of mice were disrupted with bilateral cytotoxic lesions, and standard object recognition (non-spatial) and object location recognition (spatial) were tested. In the habituation period, mice with hippocampal lesions needed a significantly longer time to fully habituate to the test box. Interestingly, after 4 days of habituation (insufficient habituation), the recognition index was similar in the sham and hippocampal lesion groups. However, exploration time was significantly shorter in mice with hippocampal lesions compared with that in control mice. Interestingly, if mice were subjected to a 10-days-long period of habituation (full habituation), the recognition index was significantly lower in mice with hippocampal lesions compared with that in control mice; however, total exploration time was similar in both groups. Furthermore, the object recognition test after full habituation occluded hippocampal long-term potentiation, a cellular model of memory. These results indicate that sufficient habituation is required to observe the effects of hippocampal lesions on object recognition memory.
Singh, Surjeet; Kaur, Harpreet; Sandhir, Rajat
Morris water maze has been widely used for analysis of cognitive functions and relies on the time taken by animal to find the platform i.e. escape latency as a parameter to quantify spatial memory and learning. However, escape latency is confounded by swimming speed which is not necessarily a cognitive factor. Rather, path length may be a more appropriate and reliable parameter to assess spatial learning. This paper presents fractal dimension as a new paradigm to assess spatial memory and learning in animals. Male wistar rats were administrated with pentylenetetrazole and scopolamine to induce chronic epilepsy and dementia respectively. Fractal dimension of the random path followed by the animals on Morris water maze was analyzed and statistically compared among different experimental groups; the results suggest that fractal dimension is more reliable and accurate parameter to assess cognitive deficits compared to escape latency. Thus, the present study suggests that fractal dimensions could be used as an independent parameter to assess spatial memory and learning in animals using Morris water maze.
Ginsburg, Véronique; Gevers, Wim
The processing of numerical information induces a spatial response bias: Faster responses to small numbers with the left hand and faster responses to large numbers with the right hand. Most theories agree that long-term representations underlie this so called SNARC effect (Spatial Numerical Association of Response Codes; Dehaene et al., 1993). However, a spatial response bias was also observed with the activation of temporary position-space associations in working memory (ordinal position effect; van Dijck and Fias, 2011). Items belonging to the beginning of a memorized sequence are responded to faster with the left hand side while items at the end of the sequence are responded to faster with the right hand side. The theoretical possibility was put forward that the SNARC effect is an instance of the ordinal position effect, with the empirical consequence that the SNARC effect and the ordinal position effect cannot be observed simultaneously. In two experiments we falsify this claim by demonstrating that the SNARC effect and the ordinal position effect are not mutually exclusive. Consequently, this suggests that the SNARC effect and the ordinal position effect result from the activation of different representations. We conclude that spatial response biases can result from the activation of both pre-existing positions in long-term memory and from temporary space associations in working memory at the same time. PMID:25688199
Eggert, Thomas; Drever, Johannes; Straube, Andreas
Some types of human sequential memory, e.g. the acquisition of a new composition by a trained musician, seem to be very efficient in extending the length of a memorized sequence and in flexible reuse of known subsequences in a newly acquired sequential context. This implies that interference between known and newly acquired subsequences can be avoided even when learning a sequence which is a partial mutation of a known sequence. It is known that established motor sequences do not have such flexibility. Using learning of deferred imitation, the current study investigates the flexibility of explicit spatial memory by quantifying the interferences between successively acquired, partially overlapping sequences. After learning a spatial sequence on day 1, this sequence was progressively modified on day 2. On day 3, a retention test was performed with both the initial and the modified sequence. The results show that subjects performed very well on day 1 and day 2. No spatial interference between changed and unchanged targets was observed during the stepwise progressive modification of the reproduced sequence. Surprisingly, subjects performed well on both sequences on day 3. Comparison with a control experiment without intermediate mutation training showed that the initial training on day 1 did not proactively interfere with the retention of the modified sequence on day 3. Vice versa, the mutation training on day 2 did not interfere retroactively with the retention of the original sequence as tested on day 3. The results underline the flexibility in acquiring explicit spatial memory.
Roth, Timothy C; Krochmal, Aaron R
The ability to learn about the spatial environment plays an important role in navigation, migration, dispersal, and foraging. However, our understanding of both the role of cognition in the development of navigation strategies and the mechanisms underlying these strategies is limited. We tested the hypothesis that complex navigation is facilitated by spatial memory in a population of Chrysemys picta that navigate with extreme precision (±3.5 m) using specific routes that must be learned prior to age three. We used scopolamine, a muscarinic acetylcholine receptor antagonist, to manipulate the cognitive spatial abilities of free-living turtles during naturally occurring overland movements. Experienced adults treated with scopolamine diverted markedly from their precise navigation routes. Naive juveniles lacking experience (and memory) were not affected by scopolamine, and thereby served as controls for perceptual or non-spatial cognitive processes associated with navigation. Further, neither adult nor juvenile movement was affected by methylscopolamine, a form of scopolamine that does not cross the blood-brain barrier, a control for the peripheral effects of scopolamine. Together, these results are consistent with a role of spatial cognition in complex navigation and highlight a cellular mechanism that might underlie spatial cognition. Overall, our findings expand our understanding of the development of complex cognitive abilities of vertebrates and the neurological mechanisms of navigation.
Peinado-Manzano, M A
Male rats received either electrolytic or sham lesions bilaterally into the amygdala, hippocampus or amygdala plus hippocampus, or were assigned to an unoperated control group. After the postoperative recovery period all lesioned and control animals were tested for the ability to master a spatial delayed non-matching-to-sample (DNMS), a visual DNMS and a visuo-tactile DNMS. Retention of these paradigms was evaluated 24 h after the last respective training session. Bilateral lesions of the amygdala severely disrupted the acquisition and retention of a DNMS paradigm with visual and visuo-tactile cues as discriminative stimuli and had no effect on the acquisition and retention of a spatial DNMS. On the contrary, bilateral lesions of the hippocampus impaired the acquisition and retention of spatial DNMS, but the animals with these lesions showed an acquisition and retention of the visual and visuo-tactile DNMS paradigms significantly better than those of animals with amygdala lesions. Combined lesions of the amygdala and hippocampus severely disrupted the acquisition and retention of the 3 paradigms. The contribution of the amygdala and the hippocampus in the working memory for spatial and non-spatial information is discussed.
Ramos, Juan M J
In a previous study we showed a temporally graded retrograde amnesia after hippocampal lesions when rats learned a spatial reference memory task in which two types of signals simultaneously indicated the goal arm (shape of the experimental room and extramaze landmarks). To investigate the effect that the navigational demands of the task have on remote memory expression, the same task was used in the present study as in our previous report, but on this occasion the shape of the surroundings was not predictive, which resulted in a highly demanding spatial task. Additionally, animals received extensive training in an early phase to ensure that the task was well learned. Results indicated a profound retrograde amnesia when dorsal hippocampal lesions were made 1 or 70 d after the end of the training (experiments 1 and 2). Using a long period of retraining, however, lesioned animals in the 70-d groups showed progressively more spared memory than the lesioned rats of the 1-d group. Experiments 3 and 4 showed that rats did not learn the above spatial task through an S-R association. Specifically, when animals acquired the task using a single cue (intra- or extramaze), hippocampal lesions did not produce retrograde amnesia. These findings support the possibility that in a highly demanding spatial task, hippocampal lesions produce a performance/navigational impairment that could interfere with the expression of spared remote spatial memory. The long period of retraining, however, seems to partially compensate for this deficit, but only when a long learning-surgery interval is employed.
Kühn, Simone; Gallinat, Jürgen
The most important cognitive domains where hippocampal formation is crucially involved are navigation and memory. Some evidence suggests that different hippocampal subregions mediate these domains. However, a quantitative meta-analysis on neuroimaging studies of spatial navigation versus memory is lacking. By means of activation likelihood estimation (ALE), we investigate concurrence of brain regions activated during spatial navigation encoding and retrieval as well as during episodic memory encoding and retrieval tasks in humans. During encoding in spatial navigation, activity was located in more posterior regions of the hippocampal formation, whereas episodic memory encoding was located in more anterior regions. Retrieval in spatial navigation was more strongly lateralized to the right compared to episodic memory retrieval. Within studies on spatial navigation retrieval, immediate recall was located more posterior and delayed recall more anterior. Overlap between concurrence of activation in spatial navigation and episodic memory was rather limited in comparison to uniquely involved regions. This argues in favor of two distinct networks, one for spatial navigation the other for episodic memory within the hippocampal formation.
Riby, Leigh M.; Orme, Elizabeth
In this study we quantify for the first time electrophysiological components associated with incorporating long-term semantic knowledge with visuo-spatial information using two variants of a traditional matrix patterns task. Results indicated that the matrix task with greater semantic content was associated with enhanced accuracy and RTs in a…
Van Skike, Candice E; Novier, Adelle; Diaz-Granados, Jaime L; Matthews, Douglas B
Using a rapid chronic intermittent ethanol (CIE) vapor exposure paradigm, we demonstrate the dissociability of metabolic tolerance from cognitive tolerance in adolescent rats. Adolescent rats were trained to spatially navigate in the Morris Water Maze and then exposed to CIE vapor or air 16 h a day for 4 days. After a final 28 h withdrawal, all rats received a saline or ethanol challenge, followed by a test of spatial memory 30 min after administration. Results indicate that CIE vapor exposure did not significantly impair adolescent spatial memory. Although CIE-exposed rats developed metabolic tolerance to a subsequent ethanol administration, CIE exposure did not alter dose-dependent ethanol-induced spatial memory impairments. These data indicate that metabolic ethanol tolerance can be distinguished from cognitive ethanol tolerance during adolescence and suggest that blood alcohol levels alone do not fully explain ethanol-induced spatial memory impairments.
Fuchs, Fanny; Cosquer, Brigitte; Penazzi, Lorène; Mathis, Chantal; Kelche, Christian; Majchrzak, Monique; Barbelivien, Alexandra
In rats, some cognitive capabilities, like spatial learning and memory, are preserved from age-related decline by whole adult life enriched environment (EE) exposure. However, to which extent late EE contributes to such maintenance remains to be investigated. Here we assessed the impact of late housing condition (e.g., from the age of 18 months) on spatial learning and memory of aged rats (24 months) previously exposed or unexposed to EE from young adulthood. The results showed that late EE was not required for spatial memory maintenance in aged rats previously housed in EE. In contrast, late EE mitigates spatial memory deficit in aged rats previously unexposed to EE. These outcomes suggest that EE exposure up to middle age provides a "reserve"-like advantage which supports an enduring preservation of spatial capabilities in old age.
Ding, Hao; Qin, Wen; Liang, Meng; Ming, Dong; Wan, Baikun; Li, Qiang; Yu, Chunshui
Early deafness can reshape deprived auditory regions to enable the processing of signals from the remaining intact sensory modalities. Cross-modal activation has been observed in auditory regions during non-auditory tasks in early deaf subjects. In hearing subjects, visual working memory can evoke activation of the visual cortex, which further contributes to behavioural performance. In early deaf subjects, however, whether and how auditory regions participate in visual working memory remains unclear. We hypothesized that auditory regions may be involved in visual working memory processing and activation of auditory regions may contribute to the superior behavioural performance of early deaf subjects. In this study, 41 early deaf subjects (22 females and 19 males, age range: 20-26 years, age of onset of deafness < 2 years) and 40 age- and gender-matched hearing controls underwent functional magnetic resonance imaging during a visuo-spatial delayed recognition task that consisted of encoding, maintenance and recognition stages. The early deaf subjects exhibited faster reaction times on the spatial working memory task than did the hearing controls. Compared with hearing controls, deaf subjects exhibited increased activation in the superior temporal gyrus bilaterally during the recognition stage. This increased activation amplitude predicted faster and more accurate working memory performance in deaf subjects. Deaf subjects also had increased activation in the superior temporal gyrus bilaterally during the maintenance stage and in the right superior temporal gyrus during the encoding stage. These increased activation amplitude also predicted faster reaction times on the spatial working memory task in deaf subjects. These findings suggest that cross-modal plasticity occurs in auditory association areas in early deaf subjects. These areas are involved in visuo-spatial working memory. Furthermore, amplitudes of cross-modal activation during the maintenance stage were
Xu, Hua; Luo, Xiaobin; Chang, Raymond Chuen-Chung; Liu, Jianjun; Yang, Xifei
Canonical transient receptor potential (TRPC) channels are widely expressed throughout the nervous system whereas their functions remain largely unclear. Here we investigated the effects of TRPC1 deletion on spatial memory ability of mice and the potential intervention by environmental enrichment (EE). Significant spatial memory impairment assessed by conditional fearing test, Y maze test and step-down test in TRPC1 knockout mice was revealed. The behavioral abnormality were attenuated by the treatment of EE. Proteomic analysis by two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) coupled with a matrix-assisted laser desorption/ionisation-time of flight (MALDI-TOF) and tandem mass spectrometry (MS) revealed that TRPC1 deletion caused differential expression of a total of 10 proteins (8 up-regulated and 2 down-regulated) in hippocampus. EE treatment resulted in differential expression of a total of 22 proteins (2 up-regulated and 20 down-regulated) in hippocampus of TRPC1 knockout mice. Among these differentially expressed proteins, the expression of α-internexin and glia maturation factor β (GMF-β), two proteins shown to impair memory, were significantly down-regulated in hippocampus of TRPC1 knockout mice by EE treatment. Taken together, these data suggested that TRPC1 regulated directly or indirectly the expression of multiple proteins, which may be crucial for the maintenance of memory ability, and that EE treatment modulated spatial memory impairment caused by TRPC1 depletion and the mechanisms may involve the modulation of EE on the expression of those dys-regulated proteins such as α-internexin and GMF-β in hippocampus. PMID:27034165
Langston, Rosamund F; Wood, Emma R
The hippocampus is thought to be required for the associative recognition of objects together with the spatial or temporal contexts in which they occur. However, recent data showing that rats with fornix lesions perform as well as controls in an object-place task, while being impaired on an object-place-context task (Eacott and Norman (2004) J Neurosci 24:1948-1953), suggest that not all forms of context-dependent associative recognition depend on the integrity of the hippocampus. To examine the role of the hippocampus in context-dependent recognition directly, the present study tested the effects of large, selective, bilateral hippocampus lesions in rats on performance of a series of spontaneous recognition memory tasks: object recognition, object-place recognition, object-context recognition and object-place-context recognition. Consistent with the effects of fornix lesions, animals with hippocampus lesions were impaired only on the object-place-context task. These data confirm that not all forms of context-dependent associative recognition are mediated by the hippocampus. Subsequent experiments suggested that the object-place task does not require an allocentric representation of space, which could account for the lack of impairment following hippocampus lesions. Importantly, as the object-place-context task has similar spatial requirements, the selective deficit in object-place-context recognition suggests that this task requires hippocampus-dependent neural processes distinct from those required for allocentric spatial memory, or for object memory, object-place memory or object-context memory. Two possibilities are that object, place, and context information converge only in the hippocampus, or that recognition of integrated object-place-context information requires a hippocampus-dependent mode of retrieval, such as recollection.
Kanngiesser, Patricia; Call, Josep
Animals commonly use feature and spatial strategies when remembering places of interest such as food sources or hiding places. We conducted three experiments with great apes to investigate strategy preferences and factors that may shape them. In the first experiment, we trained 17 apes to remember 12 different food locations on the floor of their sleeping room. The 12 food locations were associated with one feature cue, so that feature and spatial cues were confounded. In a single test session, we brought the cues into conflict and found that apes, irrespective of species, showed a preference for a feature strategy. In the second experiment, we used a similar procedure and trained 25 apes to remember one food location on a platform in front of them. On average, apes preferred to use a feature strategy but some individuals relied on a spatial strategy. In the final experiment, we investigated whether training might influence strategy preferences. We tested 21 apes in the platform set-up and found that apes used both, feature and spatial strategies irrespective of training. We conclude that apes can use feature and spatial strategies to remember the location of hidden food items, but that task demands (e.g. different numbers of search locations) can influence strategy preferences. We found no evidence, however, for the role of training in shaping these preferences.
Srimal, Riju; Curtis, Clayton E
The mechanism for the short-term maintenance of information involves persistent neural activity during the retention interval, which forms a bridge between the cued memoranda and its later contingent response. Here, we used event-related functional magnetic resonance imaging to identify cortical areas with activity that persists throughout working memory delays with the goal of testing if such activity represents visuospatial attention or prospective saccade goals. We did so by comparing two spatial working memory tasks. During a memory-guided saccade (MGS) task, a location was maintained during a delay after which a saccade was generated to the remembered location. During a spatial item recognition (SIR) task identical to MGS until after the delay, a button press indicated whether a newly cued location matched the remembered location. Activity in frontal and parietal areas persisted above baseline and was greater in the hemisphere contralateral to the cued visual field. However, delay-period activity did not differ between the tasks. Notably, in the putative frontal eye field (FEF), delay period activity did not differ despite that the precise metrics of the memory-guided saccade were known during the MGS delay and saccades were never made in SIR. Persistent FEF activity may therefore represent a prioritized attentional map of space, rather than the metrics for saccades.
Solanki, Ruchi; Chaudhary, Amrendra Kumar; Singh, Ranjit
This study was designed to investigate the nootropic activity of Capparis zeylanica Linn. leaves in rats. The raw material of Capparis zeylanica leaves was successively extracted with petroleum ether and methanol using a Soxhlet apparatus and macerated to form an aqueous extract. The methanolic and aqueous extracts were evaluated for their effect on spatial learning and memory in rats using the Morris water maze task. Three doses (50, 100 and 150 mg/kg; p.o.) of methanolic and aqueous extracts of Capparis zeylanica were administered for 7 successive days to separate groups of animals. Results showed that both the extracts significantly enhanced memory, as shown by decrease in escape latency time. Furthermore, methanolic and aqueous extracts in all doses tested significantly increased the time spent in the target quadrant during the probe trial, indicating retention of spatial memory of the location of a previously placed platform in the target quadrant. These findings indicate that methanolic and aqueous extracts of Capparis zeylanica Linn. leaves have potent nootropic activity. The anti-oxidant property of Capparis zeylanica may contribute favorably to the memory enhancement effect. However, further studies are needed to identify the exact mechanism of action.
Jacome, Luis F.; Barateli, Ketti; Buitrago, Dina; Lema, Franklin; Frankfurt, Maya
17β-estradiol (E2) rapidly, within minutes, activates behaviors and cognition by binding to membrane estrogen receptors, activating cell signaling cascades and increasing dendritic spines. In female rodents, E2 enhances spatial memory within 2–4 hours, and spine density is increased in the CA1 area of the hippocampus within 30–60 minutes. Although chronic gonadal hormone treatments in male rats alter cognition and spines/spine synapses and acute hormone effects occur in hippocampal slices, effects of acute, in vivo hormone administration in males are unknown. Therefore, we assessed rapid effects of E2 (20 μg/kg) and testosterone (T) (750 μg/kg) on spatial memory using the object placement task and on hippocampal spine density using Golgi impregnation. Orchidectomized rats received hormones immediately after the training trial and were tested for retention 2 hours later. Vehicle-injected orchidectomized males spent equal time exploring objects in the old and new locations, but E2- or T-treated subjects spent more time exploring objects at the new location, suggesting enhanced memory. Both hormones also increased spine density in CA1, but not the dentate gyrus, by 20%–40% at 30 minutes and 2 hours after injections. This report is the first, to our knowledge, to show E2 and T enhancements of memory and spine density within such a short time frame in male rats. PMID:26844375
Monje, Francisco J; Kim, Eun-Jung; Pollak, Daniela D; Cabatic, Maureen; Li, Lin; Baston, Arthur; Lubec, Gert
The focal adhesion kinase (FAK) is a non-receptor tyrosine kinase abundantly expressed in the mammalian brain and highly enriched in neuronal growth cones. Inhibitory and facilitatory activities of FAK on neuronal growth have been reported and its role in neuritic outgrowth remains controversial. Unlike other tyrosine kinases, such as the neurotrophin receptors regulating neuronal growth and plasticity, the relevance of FAK for learning and memory in vivo has not been clearly defined yet. A comprehensive study aimed at determining the role of FAK in neuronal growth, neurotransmitter release and synaptic plasticity in hippocampal neurons and in hippocampus-dependent learning and memory was therefore undertaken using the mouse model. Gain- and loss-of-function experiments indicated that FAK is a critical regulator of hippocampal cell morphology. FAK mediated neurotrophin-induced neuritic outgrowth and FAK inhibition affected both miniature excitatory postsynaptic potentials and activity-dependent hippocampal long-term potentiation prompting us to explore the possible role of FAK in spatial learning and memory in vivo. Our data indicate that FAK has a growth-promoting effect, is importantly involved in the regulation of the synaptic function and mediates in vivo hippocampus-dependent spatial learning and memory.
Korotkova, Tatiana; Fuchs, Elke C; Ponomarenko, Alexey; von Engelhardt, Jakob; Monyer, Hannah
Activity of parvalbumin-positive hippocampal interneurons is critical for network synchronization but the receptors involved therein have remained largely unknown. Here we report network and behavioral deficits in mice with selective ablation of NMDA receptors in parvalbumin-positive interneurons (NR1(PVCre-/-)). Recordings of local field potentials and unitary neuronal activity in the hippocampal CA1 area revealed altered theta oscillations (5-10 Hz) in freely behaving NR1(PVCre-/-) mice. Moreover, in contrast to controls, in NR1(PVCre-/-) mice the remaining theta rhythm was abolished by the administration of atropine. Gamma oscillations (35-85 Hz) were increased and less modulated by the concurrent theta rhythm in the mutant. Positional firing of pyramidal cells in NR1(PVCre-/-) mice was less spatially and temporally precise. Finally, NR1(PVCre-/-) mice exhibited impaired spatial working as well as spatial short- and long-term recognition memory but showed no deficits in open field exploratory activity and spatial reference learning.
Meehan, Sean; Singhal, Anthony; Fowler, Barry
The early Nd reflects the analysis of simple features of selectively attended auditory stimuli, but the precise nature of the more complex processing reflected by the late Nd is unclear. The late but not the early Nd is sensitive to interference from a concurrently presented visual spatial attention switching task. This experiment investigated whether the late Nd is also sensitive to deeper visual attention switching. Twenty-one subjects performed a dichotic listening task concurrently with either visual spatial or visual letter matching attention switching tasks. Late Nd amplitude was reduced by the spatial but not the letter matching task, indicating insensitivity to deeper attention switching. P300 amplitude was reduced by both tasks. Reductions in N100 and P200 were uncorrelated. We propose that, in part, the late Nd reflects an amodal memory trace containing spatial information, possibly involving a "where" rather than a "what" auditory pathway.
Ortiz, J Bryce; Mathewson, Coy M; Hoffman, Ann N; Hanavan, Paul D; Terwilliger, Ernest F; Conrad, Cheryl D
Chronic restraint stress impairs hippocampal-mediated spatial learning and memory, which improves following a post-stress recovery period. Here, we investigated whether brain-derived neurotrophic factor (BDNF), a protein important for hippocampal function, would alter the recovery from chronic stress-induced spatial memory deficits. Adult male Sprague-Dawley rats were infused into the dorsal hippocampal cornu ammonis (CA)3 region with an adeno-associated viral vector containing the sequence for a short hairpin RNA (shRNA) directed against BDNF or a scrambled sequence (Scr). Rats were then chronically restrained (wire mesh, 6 h/day for 21 days) and assessed for spatial learning and memory using a radial arm water maze (RAWM) either immediately after stressor cessation (Str-Imm) or following a 21-day post-stress recovery period (Str-Rec). All groups learned the RAWM task similarly, but differed on the memory retention trials. Rats in the Str-Imm group, regardless of adeno-associated viral contents, committed more errors in the spatial reference memory domain on the single retention trial during day 3 than did the non-stressed controls. Importantly, the typical improvement in spatial memory following the recovery from chronic stress was blocked with the shRNA against BDNF, as Str-Rec-shRNA performed worse on the RAWM compared with the non-stressed controls or Str-Rec-Scr. The stress effects were specific for the reference memory domain, but knockdown of hippocampal BDNF in unstressed controls briefly disrupted spatial working memory as measured by repeated entry errors on day 2 of training. These results demonstrated that hippocampal BDNF was necessary for the recovery from stress-induced hippocampal-dependent spatial memory deficits in the reference memory domain.
Haagensen, Annika M J; Grand, Nanna; Klastrup, Signe; Skytte, Christina; Sørensen, Dorte B
Two methods investigating learning and memory in juvenile Göttingen minipigs were evaluated for potential use in preclinical toxicity testing. Twelve minipigs were tested using a spatial hole-board discrimination test including a learning phase and two memory phases. Five minipigs were tested in a visual discrimination test. The juvenile minipigs were able to learn the spatial hole-board discrimination test and showed improved working and reference memory during the learning phase. Performance in the memory phases was affected by the retention intervals, but the minipigs were able to remember the concept of the test in both memory phases. Working memory and reference memory were significantly improved in the last trials of the memory phases. In the visual discrimination test, the minipigs learned to discriminate between the three figures presented to them within 9-14 sessions. For the memory test, all minipigs performed 9/12 correct choices or better. Juvenile Göttingen minipigs are able to learn to perform in a spatial hole-board discrimination test as well as in a visual discrimination test, showing an increase in performance over time. Both tests have considerable scope to assess learning and memory of pigs, and we seem to have succeeded in establishing two test systems suitable for performing preclinical toxicity testing in juvenile minipigs.
Blacker, Kara J.; Courtney, Susan M.
Previous work has demonstrated a distinction between maintenance of two types of spatial information in working memory (WM): spatial locations and spatial relations. While a body of work has investigated the neural mechanisms of sensory-based information like spatial locations, little is known about how spatial relations are maintained in WM. In two experiments, we used fMRI to investigate the involvement of early visual cortex in the maintenance of spatial relations in WM. In both experiments, we found less quadrant-specific BOLD activity in visual cortex when a single spatial relation, compared to a single spatial location, was held in WM. Also across both experiments, we found a consistent set of brain regions that were differentially activated during maintenance of locations vs. relations. Maintaining a location, compared to a relation, was associated with greater activity in typical spatial WM regions like posterior parietal cortex and prefrontal regions. Whereas maintaining a relation, compared to a location, was associated with greater activity in the parahippocampal gyrus and precuneus/retrosplenial cortex. Further, in Experiment 2 we manipulated WM load and included trials where participants had to maintain three spatial locations or relations. Under this high load condition, the regions sensitive to locations vs. relations were somewhat different than under low load. We also identified regions that were sensitive to load specifically for location or relation maintenance, as well as overlapping regions sensitive to load more generally. These results suggest that the neural substrates underlying WM maintenance of spatial locations and relations are distinct from one another and that the neural representations of these distinct types of spatial information change with load. PMID:27932963
Capitano, F; Camon, J; Licursi, V; Ferretti, V; Maggi, L; Scianni, M; Del Vecchio, G; Rinaldi, A; Mannironi, C; Limatola, C; Presutti, C; Mele, A
MicroRNAs are endogenous, noncoding RNAs crucial for the post-transcriptional regulation of gene expression. In this study, we investigated the role of miR-335-5p in spatial learning and synaptic plasticity. To this end we first showed spatial learning induced down-regulation of miR-335-5p. Next we found impairment in long-term memory and reduction in hippocampal long-term potentiation by exogenous administration of the miRNA. These findings demonstrate that miR-335-5p is a key coordinator of the intracellular pathways that mediate experience-dependent changes in the brain.
Toepper, Max; Markowitsch, Hans J; Gebhardt, Helge; Beblo, Thomas; Bauer, Eva; Woermann, Friedrich G; Driessen, Martin; Sammer, Gebhard
Healthy aging is accompanied by a decline in spatial working memory that is related to functional cerebral changes within the spatial working memory network. In the last decade, important findings were presented concerning the location (e.g., prefrontal), kind (e.g., 'underactivation,' 'overactivation'), and meaning (e.g., functional deficits, compensation) of these changes. Less is known about how functional connections between specific brain regions are affected by age and how these changes are related to behavioral performance. To address these issues, we used functional magnetic resonance imaging to examine retrieval-related brain activation and functional connectivity in 18 younger individuals and 18 older individuals. We assessed working memory with a modified version of the Corsi Block-Tapping test, which requires the storage and reproduction of spatial target sequences. Analyses of group differences in brain activation and functional connectivity included comparisons between younger individuals, older individuals, older high-performers, and older low-performers. In addition, we conducted a functional connectivity analysis by using a seed region approach. In comparison to younger individuals, older individuals showed lower right-hemispheric dorsolateral prefrontal activation and lower functional connectivity between the right dorsolateral prefrontal cortex and the bilateral orbitofrontal cortex. Older high-performers showed higher right dorsolateral and anterior prefrontal cortex activation than older low-performers, as well as higher functional connectivity between these brain regions. The present results suggest age-related reductions of prefrontal activation during spatial working memory retrieval. Moreover, task-related functional connectivity appears to be lower in older adults. Performance accuracy in older adults is associated with right dorsolateral and anterior prefrontal cortex activation, and with the functional connection between these regions.
Varga, Andrew W; Kishi, Akifumi; Mantua, Janna; Lim, Jason; Koushyk, Viachaslau; Leibert, David P; Osorio, Ricardo S; Rapoport, David M; Ayappa, Indu
Hippocampal electrophysiology and behavioral evidence support a role for sleep in spatial navigational memory, but the role of particular sleep stages is less clear. Although rodent models suggest the importance of rapid eye movement (REM) sleep in spatial navigational memory, a similar role for REM sleep has never been examined in humans. We recruited subjects with severe obstructive sleep apnea (OSA) who were well treated and adherent with continuous positive airway pressure (CPAP). Restricting CPAP withdrawal to REM through real-time monitoring of the polysomnogram provides a novel way of addressing the role of REM sleep in spatial navigational memory with a physiologically relevant stimulus. Individuals spent two different nights in the laboratory, during which subjects performed timed trials before and after sleep on one of two unique 3D spatial mazes. One night of sleep was normally consolidated with use of therapeutic CPAP throughout, whereas on the other night, CPAP was reduced only in REM sleep, allowing REM OSA to recur. REM disruption via this method caused REM sleep reduction and significantly fragmented any remaining REM sleep without affecting total sleep time, sleep efficiency, or slow-wave sleep. We observed improvements in maze performance after a night of normal sleep that were significantly attenuated after a night of REM disruption without changes in psychomotor vigilance. Furthermore, the improvement in maze completion time significantly positively correlated with the mean REM run duration across both sleep conditions. In conclusion, we demonstrate a novel role for REM sleep in human memory formation and highlight a significant cognitive consequence of OSA.
Serrano, Peter; Friedman, Eugenia L; Kenney, Jana; Taubenfeld, Stephen M; Zimmerman, Joshua M; Hanna, John; Alberini, Cristina; Kelley, Ann E; Maren, Stephen; Rudy, Jerry W; Yin, Jerry C P; Sacktor, Todd C; Fenton, André A
How long-term memories are stored is a fundamental question in neuroscience. The first molecular mechanism for long-term memory storage in the brain was recently identified as the persistent action of protein kinase Mzeta (PKMzeta), an autonomously active atypical protein kinase C (PKC) isoform critical for the maintenance of long-term potentiation (LTP). PKMzeta maintains aversively conditioned associations, but what general form of information the kinase encodes in the brain is unknown. We first confirmed the specificity of the action of zeta inhibitory peptide (ZIP) by disrupting long-term memory for active place avoidance with chelerythrine, a second inhibitor of PKMzeta activity. We then examined, using ZIP, the effect of PKMzeta inhibition in dorsal hippocampus (DH) and basolateral amygdala (BLA) on retention of 1-d-old information acquired in the radial arm maze, water maze, inhibitory avoidance, and contextual and cued fear conditioning paradigms. In the DH, PKMzeta inhibition selectively disrupted retention of information for spatial reference, but not spatial working memory in the radial arm maze, and precise, but not coarse spatial information in the water maze. Thus retention of accurate spatial, but not procedural and contextual information required PKMzeta activity. Similarly, PKMzeta inhibition in the hippocampus did not affect contextual information after fear conditioning. In contrast, PKMzeta inhibition in the BLA impaired retention of classical conditioned stimulus-unconditioned stimulus (CS-US) associations for both contextual and auditory fear, as well as instrumentally conditioned inhibitory avoidance. PKMzeta inhibition had no effect on postshock freezing, indicating fear expression mediated by the BLA remained intact. Thus, persistent PKMzeta activity is a general mechanism for both appetitively and aversively motivated retention of specific, accurate learned information, but is not required for processing contextual, imprecise, or
Thomason, Moriah E.; Race, Elizabeth; Burrows, Brittany; Whitfield-Gabrieli, Susan; Glover, Gary H.; Gabrieli, John D. E.
A core aspect of working memory (WM) is the capacity to maintain goal-relevant information in mind, but little is known about how this capacity develops in the human brain. We compared brain activation, via fMRI, between children (ages 7-12 years) and adults (ages 20-29 years) performing tests of verbal and spatial WM with varying amounts (loads)…
Allen, Richard J; Castellà, Judit; Ueno, Taiji; Hitch, Graham J; Baddeley, Alan D
A visual object can be conceived of as comprising a number of features bound together by their joint spatial location. We investigate the question of whether the spatial location is automatically bound to the features or whether the two are separable, using a previously developed paradigm whereby memory is disrupted by a visual suffix. Participants were shown a sample array of four colored shapes, followed by a postcue indicating the target for recall. On randomly intermixed trials, a to-be-ignored suffix array consisting of two different colored shapes was presented between the sample and the postcue. In a random half of suffix trials, one of the suffix items overlaid the location of the target. If location was automatically encoded, one might expect the colocation of target and suffix to differentially impair performance. We carried out three experiments, cuing for recall by spatial location (Experiment 1), color or shape (Experiment 2), or both randomly intermixed (Experiment 3). All three studies showed clear suffix effects, but the colocation of target and suffix was differentially disruptive only when a spatial cue was used. The results suggest that purely visual shape-color binding can be retained and accessed without requiring information about spatial location, even when task demands encourage the encoding of location, consistent with the idea of an abstract and flexible visual working memory system.
Chersi, Fabian; Burgess, Neil
Spatial navigation can serve as a model system in cognitive neuroscience, in which specific neural representations, learning rules, and control strategies can be inferred from the vast experimental literature that exists across many species, including humans. Here, we review this literature, focusing on the contributions of hippocampal and striatal systems, and attempt to outline a minimal cognitive architecture that is consistent with the experimental literature and that synthesizes previous related computational modeling. The resulting architecture includes striatal reinforcement learning based on egocentric representations of sensory states and actions, incidental Hebbian association of sensory information with allocentric state representations in the hippocampus, and arbitration of the outputs of both systems based on confidence/uncertainty in medial prefrontal cortex. We discuss the relationship between this architecture and learning in model-free and model-based systems, episodic memory, imagery, and planning, including some open questions and directions for further experiments.
Thibault, Guillaume; Pasqualotto, Achille; Vidal, Manuel; Droulez, Jacques; Berthoz, Alain
Although a number of studies have been devoted to 2-D navigation, relatively little is known about how the brain encodes and recalls navigation in complex multifloored environments. Previous studies have proposed that humans preferentially memorize buildings by a set of horizontal 2-D representations. Yet this might stem from the fact that environments were also explored by floors. Here, we have investigated the effect of spatial learning on memory of a virtual multifloored building. Two groups of 28 participants watched a computer movie that showed either a route along floors one at a time or travel between floors by simulated lifts, consisting in both cases of a 2-D trajectory in the vertical plane. To test recognition, the participants viewed a camera movement that either replicated a segment of the learning route (familiar segment) or did not (novel segment-i.e., shortcuts). Overall, floor recognition was not reliably superior to column recognition, but learning along a floor route produced a better spatial memory performance than did learning along a column route. Moreover, the participants processed familiar segments more accurately than novel ones, not only after floor learning, but crucially, also after column learning, suggesting a key role of the observation mode on the exploitation of spatial memory.
Cornoldi, C; Rigoni, F; Venneri, A; Vecchi, T
The distinction between passive and active visuo-spatial memory has been useful to interpret various pattern of deficits reported in individual differences studies. However, this interpretation raises the issue of task difficulty, since active tasks could be failed simply because more complex and the corresponding deficit could reflect a reduced capacity of the system. We describe two children with Nonverbal Learning Disability whose performance provides evidence of a dissociation between passive and active memory processes. One of the children showed a selective impairment in passive tasks and performed flawlessly in active tasks, whereas the second child displayed the opposite pattern. These data suggest that a qualitative difference between passive and active processes does exist and that differences in performance do not reflect a lower/higher level of task difficulty. Further, these data underlie the importance of formulating theoretical models of visuo-spatial memory including both material-related (i.e., visual vs spatial) and process-related (i.e., passive vs active) distinctions.
Gutiérrez-Garralda, Juan M; Hernandez-Castillo, Carlos R; Barrios, Fernando A; Pasaye, Erick H; Fernandez-Ruiz, Juan
Visuospatial working memory refers to the short-term storage and manipulation of visuospatial information. To study the neural bases of these processes, 17 participants took part in a modified sequential Vernier task while they were being scanned using an event-related functional MRI protocol. During each trial, participants retained the spatial position of a line during a delay period to later evaluate if it was presented aligned to a second line. This design allowed testing the manipulation of the spatial information from memory. During encoding, there was a larger parietal and cingulate activation under the experimental condition, whereas the opposite was true for the occipital cortex. Throughout the delay period of the experimental condition there was significant bilateral activation in the caudal superior frontal sulcus/middle frontal gyrus, as well as the insular and superior parietal lobes, which confirms the findings from previous studies. During manipulation of spatial memory, the analysis showed higher activation in the lingual gyrus. This increase of activity in visual areas during the manipulation phase fits with the hypothesis that information stored in sensory cortices becomes reactivated once the information is needed to be utilized.
Taridi, Nursiati Mohamad; Abd Rani, Nazirah; Abd Latiff, Azian; Ngah, Wan Zurinah Wan; Mazlan, Musalmah
Little is known about the effect of vitamin E on brain function. Therefore, in this study we evaluated the effect of tocotrienol rich fraction (TRF) on behavioral impairment and oxidative stress in aged rats. Thirty-six male Wistar rats (young: 3-months-old; aged: 21-months-old) were treated with either the control (olive oil) or TRF (200 mg/kg) for 3 months. Behavioral studies were performed using the open field test and Morris water maze (MWM) task. Blood was taken for assessment of DNA damage, plasma malondialdehyde (MDA) and vitamin E, and erythrocyte antioxidant enzyme activity. Brains were also collected to measure vitamin E levels. Results showed that aged rats exhibited reduced exploratory activity, enhanced anxiety and decreased spatial learning and memory compared with young rats. DNA damage and plasma MDA were increased, and vitamin E levels in plasma and brain were reduced in aged rats. Aged rats supplemented with TRF showed a markedly reduced level of anxiety, improved spatial learning and memory, reduced amount and severity of DNA damage, a reduced level of MDA, and increased levels of antioxidant enzyme activity and plasma/brain vitamin E compared with age-matched controls. In conclusion, TRF supplementation reverses spatial learning and memory decline and decreases oxidative stress in aged rats.
Rodríguez-Andrés, David; Juan, M-Carmen; Méndez-López, Magdalena; Pérez-Hernández, Elena; Lluch, Javier
This paper presents the MnemoCity task, which is a 3D application that introduces the user into a totally 3D virtual environment to evaluate spatial short-term memory. A study has been carried out to validate the MnemoCity task for the assessment of spatial short-term memory in children, by comparing the children's performance in the developed task with current approaches. A total of 160 children participated in the study. The task incorporates two types of interaction: one based on standard interaction and another one based on natural interaction involving physical movement by the user. There were no statistically significant differences in the results of the task using the two types of interaction. Furthermore, statistically significant differences were not found in relation to gender. The correlations between scores were obtained using the MnemoCity task and a traditional procedure for assessing spatial short-term memory. Those results revealed that the type of interaction used did not affect the performance of children in the MnemoCity task.
Ozawa, Takaaki; Yamada, Kazuo; Ichitani, Yukio
In order to investigate the role of brain-derived neurotrophic factor (BDNF) in the consolidation of spatial memory, we examined the relationship between the increase of hippocampal BDNF and the establishment of long-term spatial memory in spontaneous place recognition test in rats. The test consisted of a sample phase, delay interval, and a test phase, and preferred exploration of the object in a novel place compared with that in a familiar place was assessed in the test phase. In experiment 1, dorsal hippocampal administration of anisomycin, a protein synthesis inhibitor, before the sample phase (20 min) abolished the preference for the novel place object in the test phase conducted 24h later. This impairment was reversed by the dorsal hippocampal BDNF treatment immediately after the sample phase, although the BDNF treatment alone did not improve performance. In experiment 2, we used a shorter sample phase condition (5 min) in which control rats did not show any preference for the novel place object in the test phase after 24h delay, and found that BDNF treatment immediately after the sample phase caused rats' significant preference for it. Results suggest an important role of hippocampal BDNF as a product of protein synthesis that is required for the consolidation of spatial memory.
Rodríguez-Andrés, David; Méndez-López, Magdalena; Pérez-Hernández, Elena; Lluch, Javier
This paper presents the MnemoCity task, which is a 3D application that introduces the user into a totally 3D virtual environment to evaluate spatial short-term memory. A study has been carried out to validate the MnemoCity task for the assessment of spatial short-term memory in children, by comparing the children’s performance in the developed task with current approaches. A total of 160 children participated in the study. The task incorporates two types of interaction: one based on standard interaction and another one based on natural interaction involving physical movement by the user. There were no statistically significant differences in the results of the task using the two types of interaction. Furthermore, statistically significant differences were not found in relation to gender. The correlations between scores were obtained using the MnemoCity task and a traditional procedure for assessing spatial short-term memory. Those results revealed that the type of interaction used did not affect the performance of children in the MnemoCity task. PMID:27579715
Hescham, Sarah; Temel, Yasin; Schipper, Sandra; Lagiere, Mélanie; Schönfeld, Lisa-Maria; Blokland, Arjan; Jahanshahi, Ali
Deep brain stimulation (DBS) is an established symptomatic treatment modality for movement disorders and constitutes an emerging therapeutic approach for the treatment of memory impairment. In line with this, fornix DBS has shown to ameliorate cognitive decline associated with dementia. Nonetheless, mechanisms mediating clinical effects in demented patients or patients with other neurological disorders are largely unknown. There is evidence that DBS is able to modulate neurophysiological activity in targeted brain regions. We therefore hypothesized that DBS might be able to influence cognitive function via activity-dependent regulation of hippocampal neurogenesis. Using stimulation parameters, which were validated to restore memory loss in a previous behavioral study, we here assessed long-term effects of fornix DBS. To do so, we injected the thymidine analog, 5-bromo-2'-deoxyuridine (BrdU), after DBS and perfused the animals 6.5 weeks later. A week prior to perfusion, memory performance was assessed in the water maze. We found that acute stimulation of the fornix improved spatial memory performance in the water maze when the probe trial was performed 1 h after the last training session. However, no evidence for stimulation-induced neurogenesis was found in fornix DBS rats when compared to sham. Our results suggest that fornix DBS improves memory functions independent of hippocampal neurogenesis, possibly through other mechanisms such as synaptic plasticity and acute neurotransmitter release.
Wang, Juan; Liu, Li-Na; Dong, En-Zeng; Wang, Li
To deeply understand the emergence of cooperation in natural, social and economical systems, we present an improved fitness evaluation mechanism with memory in spatial prisoner's dilemma game on regular lattices. In our model, the individual fitness is not only determined by the payoff in the current game round, but also by the payoffs in previous round bins. A tunable parameter, termed as the memory strength (μ), which lies between 0 and 1, is introduced into the model to regulate the ratio of payoffs of current and previous game rounds in the individual fitness calculation. When μ = 0, our model is reduced to the standard prisoner's dilemma game; while μ = 1 represents the case in which the payoff is totally determined by the initial strategies and thus it is far from the realistic ones. Extensive numerical simulations indicate that the memory effect can substantially promote the evolution of cooperation. For μ < 1, the stronger the memory effect, the higher the cooperation level, but μ = 1 leads to a pathological state of cooperation, but can partially enhance the cooperation in the very large temptation parameter. The current results are of great significance for us to account for the role of memory effect during the evolution of cooperation among selfish players.
Galani, Rodrigue; Lehmann, Olivia; Bolmont, Tristan; Aloy, Elizabeth; Bertrand, Fabrice; Lazarus, Christine; Jeltsch, Hélène; Cassel, Jean-Christophe
Adult male Long-Evans rats were subjected to bilateral lesions of the cholinergic neurons in the nucleus basalis magnocellularis (NBM) by injection of 0.2 or 0.4 microg 192-IgG-saporin in 0.4 microl phosphate-buffered saline. Control rats received an equivalent amount of phosphate-buffered saline. Starting 2 weeks after surgery, all rats were tested for locomotor activity in their home cage, beam-walking performance, T-maze alternation rates (working memory), reference and working memory performance in a water-maze task, and memory capabilities in the eight-arm radial maze task using uninterrupted and interrupted (delay of 2 min, 2 h and 6 h after four arms had been visited) testing procedures. Histochemical analysis showed a significant decrease of acetylcholinesterase (AChE)-positive reaction products (30-66%) in various cortical regions at the 0.2-microg dose. At the dose of 0.4 microg, there was an additional, although weak, damage to the hippocampus (17-30%) and the cingulate cortex (34%). The behavioral results showed only minor impairments in spatial memory tasks, and only during initial phases of the tests (reference memory in the water maze, working memory in the radial maze). The behavioral effects of the dramatic cholinergic lesions do not support the idea of a substantial implication of cholinergic projections from the NBM to the cortex in the memory processes assessed in this study, but they remain congruent with an involvement of these projections in attentional functions.
Thaler, Lore; Goodale, Melvyn A
Studies that have investigated how sensory feedback about the moving hand is used to control hand movements have relied on paradigms such as pointing or reaching that require subjects to acquire target locations. In the context of these target-directed tasks, it has been found repeatedly that the human sensory-motor system relies heavily on visual feedback to control the ongoing movement. This finding has been formalized within the framework of statistical optimality according to which different sources of sensory feedback are combined such as to minimize variance in sensory information during movement control. Importantly, however, many hand movements that people perform every day are not target-directed, but based on allocentric (object-centered) visual information. Examples of allocentric movements are gesture imitation, drawing, or copying. Here we tested if visual feedback about the moving hand is used in the same way to control target-directed and allocentric hand movements. The results show that visual feedback is used significantly more to reduce movement scatter in the target-directed as compared with the allocentric movement task. Furthermore, we found that differences in the use of visual feedback between target-directed and allocentric hand movements cannot be explained based on differences in uncertainty about the movement goal. We conclude that the role played by visual feedback for movement control is fundamentally different for target-directed and allocentric movements. The results suggest that current computational and neural models of sensorimotor control that are based entirely on data derived from target-directed paradigms have to be modified to accommodate performance in the allocentric tasks used in our experiments. As a consequence, the results cast doubt on the idea that models of sensorimotor control developed exclusively from data obtained in target-directed paradigms are also valid in the context of allocentric tasks, such as drawing
Reichelt, Amy C.; Morris, Margaret J.; Westbrook, Reginald Frederick
High sugar diets reduce hippocampal neurogenesis, which is required for minimizing interference between memories, a process that involves "pattern separation." We provided rats with 2 h daily access to a sucrose solution for 28 d and assessed their performance on a spatial memory task. Sucrose consuming rats discriminated between objects…
Richard, Laurence; Waller, David
Mou, Zhao, and McNamara (2007) proposed the "intrinsic model of human spatial memory," which posits that a viewer's memory of an array of objects will exhibit a preferred direction that is aligned with an intrinsic axis of the array. They defined intrinsic axes as salient axes created in part by the physical (geometric) properties of the…
Shiels, Keri; Hawk, Larry W., Jr.; Lysczek, Cynthia L.; Tannock, Rosemary; Pelham, William E., Jr.; Spencer, Sarah V.; Gangloff, Brian P.; Waschbusch, Daniel A.
Working memory is one of several putative core neurocognitive processes in attention-deficit/hyperactivity disorder (ADHD). The present work seeks to determine whether visual-spatial working memory is sensitive to motivational incentives, a laboratory analogue of behavioral treatment. Participants were 21 children (ages 7-10) with a diagnosis of…
Rhodes, Sinead M.; Riby, Deborah M.; Fraser, Emma; Campbell, Lorna Elise
The present study investigated verbal and spatial working memory (WM) functioning in individuals with the neuro-developmental disorder Williams syndrome (WS) using WM component tasks. While there is strong evidence of WM impairments in WS, previous research has focused on short-term memory and has neglected assessment of executive components of…
Sixty kindergarten, sixty second grade, and sixty fourth grade students performed several memory tasks under one of six conditions. The conditions differed as to the method of presentation of information. The study focused on developmental changes in children's use of verbal, nonverbal, and spatial-positional cues for memory. (Editor)
Robin, Jessica; Hirshhorn, Marnie; Rosenbaum, R Shayna; Winocur, Gordon; Moscovitch, Morris; Grady, Cheryl L
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.
Sinnott, Jan D.; And Others
As part of an experimental research program on lifespan naturalistic and laboratory memory for spatial representation, investigators examined interactions between the effects of visual and kinesthetic encoding and age on memory for space using a modification of the Sinnott (1987) human maze paradigm. It was hypothesized that an age effect favoring…
Ferreira-Vieira, Talita H; Bastos, Cristiane P; Pereira, Grace S; Moreira, Fabricio A; Massensini, André R
It is well known that physical exercise has positive effects on cognitive functions and hippocampal plasticity. However, the underlying mechanisms have remained to be further investigated. Here we investigated the hypothesis that the memory-enhancement promoted by physical exercise relies on facilitation of the endocannabinoid system. We observed that the spatial memory tested in the object location paradigm did not persist in sedentary mice, but could be improved by 1 week of treadmill running. In addition, exercise up-regulated CB1 receptor and BDNF expression in the hippocampus. To verify if these changes required CB1 activation, we treated the mice with the selective antagonist, AM251, before each period of physical activity. In line with our hypothesis, this drug prevented the exercise-induced memory enhancement and BDNF expression. Furthermore, AM251 reduced CB1 expression. To test if facilitating the endocannabinoid system signaling would mimic the alterations observed after exercise, we treated sedentary animals during 1 week with the anandamide-hydrolysis inhibitor, URB597. Mice treated with this drug recognized the object in a new location and have increased levels of CB1 and BDNF expression in the hippocampus, showing that potentiating the endocanabinoid system equally benefits memory. In conclusion, the favorable effects of exercise upon spatial memory and BDNF expression depend on facilitation of CB1 receptor signaling, which can be mimic by inhibition of anandamide hydrolysis in sedentary animals. Our results suggest that, at least in part, the promnesic effect of the exercise is dependent of CB1 receptor activation and is mediated by BDNF.
Hardiess, Gregor; Hansmann-Roth, Sabrina; Mallot, Hanspeter A.
Street crossing under traffic is an everyday activity including collision detection as well as avoidance of objects in the path of motion. Such tasks demand extraction and representation of spatio-temporal information about relevant obstacles in an optimized format. Relevant task information is extracted visually by the use of gaze movements and represented in spatial working memory. In a virtual reality traffic intersection task, subjects are confronted with a two-lane intersection where cars are appearing with different frequencies, corresponding to high and low traffic densities. Under free observation and exploration of the scenery (using unrestricted eye and head movements) the overall task for the subjects was to predict the potential-of-collision (POC) of the cars or to adjust an adequate driving speed in order to cross the intersection without collision (i.e., to find the free space for crossing). In a series of experiments, gaze movement parameters, task performance, and the representation of car positions within working memory at distinct time points were assessed in normal subjects as well as in neurological patients suffering from homonymous hemianopia. In the following, we review the findings of these experiments together with other studies and provide a new perspective of the role of gaze behavior and spatial memory in collision detection and avoidance, focusing on the following questions: (1) which sensory variables can be identified supporting adequate collision detection? (2) How do gaze movements and working memory contribute to collision avoidance when multiple moving objects are present and (3) how do they correlate with task performance? (4) How do patients with homonymous visual field defects (HVFDs) use gaze movements and working memory to compensate for visual field loss? In conclusion, we extend the theory of collision detection and avoidance in the case of multiple moving objects and provide a new perspective on the combined operation of
Hardiess, Gregor; Hansmann-Roth, Sabrina; Mallot, Hanspeter A
Street crossing under traffic is an everyday activity including collision detection as well as avoidance of objects in the path of motion. Such tasks demand extraction and representation of spatio-temporal information about relevant obstacles in an optimized format. Relevant task information is extracted visually by the use of gaze movements and represented in spatial working memory. In a virtual reality traffic intersection task, subjects are confronted with a two-lane intersection where cars are appearing with different frequencies, corresponding to high and low traffic densities. Under free observation and exploration of the scenery (using unrestricted eye and head movements) the overall task for the subjects was to predict the potential-of-collision (POC) of the cars or to adjust an adequate driving speed in order to cross the intersection without collision (i.e., to find the free space for crossing). In a series of experiments, gaze movement parameters, task performance, and the representation of car positions within working memory at distinct time points were assessed in normal subjects as well as in neurological patients suffering from homonymous hemianopia. In the following, we review the findings of these experiments together with other studies and provide a new perspective of the role of gaze behavior and spatial memory in collision detection and avoidance, focusing on the following questions: (1) which sensory variables can be identified supporting adequate collision detection? (2) How do gaze movements and working memory contribute to collision avoidance when multiple moving objects are present and (3) how do they correlate with task performance? (4) How do patients with homonymous visual field defects (HVFDs) use gaze movements and working memory to compensate for visual field loss? In conclusion, we extend the theory of collision detection and avoidance in the case of multiple moving objects and provide a new perspective on the combined operation of
Griffin, Amy L
Despite decades of research, the neural mechanisms of spatial working memory remain poorly understood. Although the dorsal hippocampus is known to be critical for memory-guided behavior, experimental evidence suggests that spatial working memory depends not only on the hippocampus itself, but also on the circuit comprised of the hippocampus and the medial prefrontal cortex (mPFC). Disruption of hippocampal-mPFC interactions may result in failed transfer of spatial and contextual information processed by the hippocampus to the circuitry in mPFC responsible for decision making and goal-directed behavior. Oscillatory synchrony between the hippocampus and mPFC has been shown to increase in tasks with high spatial working memory demand. However, the mechanisms and circuitry supporting hippocampal-mPFC interactions during these tasks is unknown. The midline thalamic nucleus reuniens (RE) is reciprocally connected to both the hippocampus and the mPFC and has been shown to be critical for a variety of working memory tasks. Therefore, it is likely that hippocampal-mPFC oscillatory synchrony is modulated by RE activity. This article will review the anatomical connections between the hippocampus, mPFC and RE along with the behavioral studies that have investigated the effects of RE disruption on working memory task performance. The article will conclude with suggestions for future directions aimed at identifying the specific role of the RE in regulating functional interactions between the hippocampus and the PFC and investigating the degree to which these interactions contribute to spatial working memory.
Oberlin, Lauren E; Verstynen, Timothy D; Burzynska, Agnieszka Z; Voss, Michelle W; Prakash, Ruchika Shaurya; Chaddock-Heyman, Laura; Wong, Chelsea; Fanning, Jason; Awick, Elizabeth; Gothe, Neha; Phillips, Siobhan M; Mailey, Emily; Ehlers, Diane; Olson, Erin; Wojcicki, Thomas; McAuley, Edward; Kramer, Arthur F; Erickson, Kirk I
White matter structure declines with advancing age and has been associated with a decline in memory and executive processes in older adulthood. Yet, recent research suggests that higher physical activity and fitness levels may be associated with less white matter degeneration in late life, although the tract-specificity of this relationship is not well understood. In addition, these prior studies infrequently associate measures of white matter microstructure to cognitive outcomes, so the behavioral importance of higher levels of white matter microstructural organization with greater fitness levels remains a matter of speculation. Here we tested whether cardiorespiratory fitness (VO2max) levels were associated with white matter microstructure and whether this relationship constituted an indirect pathway between cardiorespiratory fitness and spatial working memory in two large, cognitively and neurologically healthy older adult samples. Diffusion tensor imaging was used to determine white matter microstructure in two separate groups: Experiment 1, N=113 (mean age=66.61) and Experiment 2, N=154 (mean age=65.66). Using a voxel-based regression approach, we found that higher VO2max was associated with higher fractional anisotropy (FA), a measure of white matter microstructure, in a diverse network of white matter tracts, including the anterior corona radiata, anterior internal capsule, fornix, cingulum, and corpus callosum (PFDR-corrected<.05). This effect was consistent across both samples even after controlling for age, gender, and education. Further, a statistical mediation analysis revealed that white matter microstructure within these regions, among others, constituted a significant indirect path between VO2max and spatial working memory performance. These results suggest that greater aerobic fitness levels are associated with higher levels of white matter microstructural organization, which may, in turn, preserve spatial memory performance in older adulthood.
Nakamura, Tomoe Y.; Nakao, Shu; Nakajo, Yukako; Takahashi, Jun C.; Wakabayashi, Shigeo; Yanamoto, Hiroji
Intracellular Ca2+ signaling regulates diverse functions of the nervous system. Many of these neuronal functions, including learning and memory, are regulated by neuronal calcium sensor-1 (NCS-1). However, the pathways by which NCS-1 regulates these functions remain poorly understood. Consistent with the findings of previous reports, we revealed that NCS-1 deficient (Ncs1-/-) mice exhibit impaired spatial learning and memory function in the Morris water maze test, although there was little change in their exercise activity, as determined via treadmill-analysis. Expression of brain-derived neurotrophic factor (BDNF; a key regulator of memory function) and dopamine was significantly reduced in the Ncs1-/- mouse brain, without changes in the levels of glial cell-line derived neurotrophic factor or nerve growth factor. Although there were no gross structural abnormalities in the hippocampi of Ncs1-/- mice, electron microscopy analysis revealed that the density of large dense core vesicles in CA1 presynaptic neurons, which release BDNF and dopamine, was decreased. Phosphorylation of Ca2+/calmodulin-dependent protein kinase II-α (CaMKII-α, which is known to trigger long-term potentiation and increase BDNF levels, was significantly reduced in the Ncs1-/- mouse brain. Furthermore, high voltage electric potential stimulation, which increases the levels of BDNF and promotes spatial learning, significantly increased the levels of NCS-1 concomitant with phosphorylated CaMKII-α in the hippocampus; suggesting a close relationship between NCS-1 and CaMKII-α. Our findings indicate that NCS-1 may regulate spatial learning and memory function at least in part through activation of CaMKII-α signaling, which may directly or indirectly increase BDNF production. PMID:28122057
Edalatmanesh, Mohammad Amin; Nikfarjam, Haniyeh; Vafaee, Farzaneh; Moghadas, Marzieh
Autism is characterized by behavioral impairments in three main domains: social interaction; language, communication and imaginative play; and the range of interests and activities. However, neuronal processing studies have suggested that hyper-perception, hyper-attention, and enhanced memory, which may lie at the heart of most autistic symptoms. Pregnant Wistar rats were administered by either Valproic Acid (VPA, 500mg/kg) or Phosphate Buffer Saline (PBS) during fetal neural tube development on embryonic day 12.5. All offspring were subjected to various tests. The present study examined social interaction, repetitive behaviors, nociception and tactile threshold, anxiety as well as spatial memory. Histological analyses of cells in five regions of the hippocampus were done to determine neuronal density in both groups. A single intra-peritoneal injection of VPA to pregnant rats produced severe autistic-like symptoms in the offspring. The results showed significant behavioral impairments such as a lower tendency to initiate social interactions, enhanced stereotyped, repetitive behaviors, increased nociception threshold and anxiety at postnatal day (PND) 30 and PND 60. The Morris water maze learning paradigm revealed enhanced spatial memory at PND 60. Furthermore, histological analysis showed that the neuronal density in five separate regions of hippocampus (CA1, CA2, CA3, Dentate gyrus and Subiculum) were increased at PND 67. This work suggests that early embryonic exposure to VPA in rats provides a good model for several specific aspects of autism and should help to continue to explore pathophysiological and neuroanatomical hypotheses. This study provides further evidence to support the notion that spatial memory and hippocampal cell density are increased in this animal model of autism.
Mohammadi-Farani, Ahmad; Haghighi, Arash; Ghazvineh, Milad
There are many discrepancies around the effect of sex hormones on spatial learning and memory in rodents. The aim of the present study was to investigate the effects of chronic administration of estradiol (ES) and testosterone (TES) on spatial memory in adult castrated male rats. Cholinesterase activity of the hippocampus in treated animals was also measured to seek if hormonal treatment can change the acetylcholinesterase (AChE) activity in this region. Six groups of castrated male rats received different doses of ES valerate (1, 4, 10 mg/kg, by subcutaneous, sc) and TES enanthate (10, 20, 40 mg/kg, sc) in weekly injection intervals for 6 weeks. Morris water maze (MWM) was used to assess the spatial reference memory of the rats. The specific activity of AChE in the hippocampus was also measured. The treatment duration and the dose quantity of ES had significant (P<0.001 and P=0.048, respectively) effect on the learning ability in the rats. For TES treated rats, treatment duration showed a significant effect (P<0.001) on learning performance of the rats. The activity of AChE compared to the control group was significantly increased in ES treated rats in a dose dependent manner and it was decreased in the group that received the highest dose of TES. Our results showed that chronic high dose of ES decreased the learning ability of male castrated rats in a reference memory version of MWM test. This can be explained by the decreased AChE activity in the hippocampus. PMID:26752989
Pašukonis, Andrius; Trenkwalder, Katharina; Ringler, Max; Ringler, Eva; Mangione, Rosanna; Steininger, Jolanda; Warrington, Ian; Hödl, Walter
The ability to associate environmental cues with valuable resources strongly increases the chances of finding them again, and thus memory often guides animal movement. For example, many temperate region amphibians show strong breeding site fidelity and will return to the same areas even after the ponds have been destroyed. In contrast, many tropical amphibians depend on exploitation of small, scattered and fluctuating resources such as ephemeral pools for reproduction. It remains unknown whether tropical amphibians rely on spatial memory for effective exploitation of their reproductive resources. Poison frogs (Dendrobatidae) routinely shuttle their tadpoles from terrestrial clutches to dispersed aquatic deposition sites. We investigated the role of spatial memory for relocating previously discovered deposition sites in an experimental population of the brilliant-thighed poison frog, Allobates femoralis, a species with predominantly male tadpole transport. We temporarily removed an array of artificial pools that served as the principal tadpole deposition resource for the population. In parallel, we set up an array of sham sites and sites containing conspecific tadpole odour cues. We then quantified the movement patterns and site preferences of tadpole-transporting males by intensive sampling of the area and tracking individual frogs. We found that tadpole-carrier movements were concentrated around the exact locations of removed pools and most individuals visited several removed pool sites. In addition, we found that tadpole-transporting frogs were attracted to novel sites that contained high concentrations of conspecific olfactory tadpole cues. Our results suggest that A. femoralis males rely heavily on spatial memory for efficient exploitation of multiple, widely dispersed deposition sites once they are discovered. Additionally, olfactory cues may facilitate the initial discovery of the new sites. PMID:28239185
Mackey, Wayne E.; Devinsky, Orrin; Doyle, Werner K.; Meager, Michael R.
A dominant theory, based on electrophysiological and lesion evidence from nonhuman primate studies, posits that the dorsolateral prefrontal cortex (dlPFC) stores and maintains working memory (WM) representations. Yet, neuroimaging studies have consistently failed to translate these results to humans; these studies normally find that neural activity persists in the human precentral sulcus (PCS) during WM delays. Here, we attempt to resolve this discrepancy. To test the degree to which dlPFC is necessary for WM, we compared the performance of patients with dlPFC lesions and neurologically healthy controls on a memory-guided saccade task that was used in the monkey studies to measure spatial WM. We found that dlPFC damage only impairs the accuracy of memory-guided saccades if the damage impacts the PCS; lesions to dorsolateral dlPFC that spare the PCS have no effect on WM. These results identify the necessary subregion of the frontal cortex for WM and specify how this influential animal model of human cognition must be revised. SIGNIFICANCE STATEMENT High-level cognition depends on working memory (WM) as a critical building block, and many symptoms of psychiatric disorders may be the direct result of impaired WM. Canonical theory posits a critical role for the dorsolateral prefrontal cortex (dlPFC) in WM based on studies of nonhuman primates. However, we find that spatial WM in humans is intact after dlPFC damage unless it impacts the more caudal PCS. Therefore, the human dlPFC is not necessary for spatial WM and highlights the need for careful translation of animal models of human cognition. PMID:26961941
Schluessel, Vera; Bleckmann, Horst
Like other vertebrates, fish can learn to solve a wide variety of tasks; however, many of their cognitive abilities, particularly in cartilaginous fishes, still remain unknown. This study investigated memory retention capabilities of spatial learning tasks in the grey bamboo shark (Chiloscyllium griseum, n=8) after behavioural training in a two-choice experiment (T-maze). Sharks learned to obtain food at a goal location, either by performing a specific turn response or by using a variety of external landmarks for guidance. Following successful training, sharks were subjected to several training breaks ranging from one to six weeks, after which they were tested again for memory retention capabilities. Sharks successfully mastered the spatial tasks after 5-21 sessions and retained this knowledge in the absence of reinforcement for a period of up to six weeks. This is the first study to show that sharks, like stingrays and other vertebrates, can solve spatial tasks and retain spatial knowledge for an extended period of time, possibly aiding them in activities such as food retrieval, predator avoidance, mate choice and habitat selection.
Meilinger, Tobias; Frankenstein, Julia; Simon, Nadine; Bülthoff, Heinrich H; Bresciani, Jean-Pierre
Reference frames in spatial memory encoding have been examined intensively in recent years. However, their importance for recall has received considerably less attention. In the present study, passersby used tags to arrange a configuration map of prominent city center landmarks. It has been shown that such configurational knowledge is memorized within a north-up reference frame. However, participants adjusted their maps according to their body orientations. For example, when participants faced south, the maps were likely to face south-up. Participants also constructed maps along their location perspective-that is, the self-target direction. If, for instance, they were east of the represented area, their maps were oriented west-up. If the location perspective and body orientation were in opposite directions (i.e., if participants faced away from the city center), participants relied on location perspective. The results indicate that reference frames in spatial recall depend on the current situation rather than on the organization in long-term memory. These results cannot be explained by activation spread within a view graph, which had been used to explain similar results in the recall of city plazas. However, the results are consistent with forming and transforming a spatial image of nonvisible city locations from the current location. Furthermore, prior research has almost exclusively focused on body- and environment-based reference frames. The strong influence of location perspective in an everyday navigational context indicates that such a reference frame should be considered more often when examining human spatial cognition.
Vytal, Katherine E; Cornwell, Brian R; Letkiewicz, Allison M; Arkin, Nicole E; Grillon, Christian
Anxiety can be distracting, disruptive, and incapacitating. Despite problems with empirical replication of this phenomenon, one fruitful avenue of study has emerged from working memory (WM) experiments where a translational method of anxiety induction (risk of shock) has been shown to disrupt spatial and verbal WM performance. Performance declines when resources (e.g., spatial attention, executive function) devoted to goal-directed behaviors are consumed by anxiety. Importantly, it has been shown that anxiety-related impairments in verbal WM depend on task difficulty, suggesting that cognitive load may be an important consideration in the interaction between anxiety and cognition. Here we use both spatial and verbal WM paradigms to probe the effect of cognitive load on anxiety-induced WM impairment across task modality. Subjects performed a series of spatial and verbal n-back tasks of increasing difficulty (1, 2, and 3-back) while they were safe or at risk for shock. Startle reflex was used to probe anxiety. Results demonstrate that induced-anxiety differentially impacts verbal and spatial WM, such that low and medium-load verbal WM is more susceptible to anxiety-related disruption relative to high-load, and spatial WM is disrupted regardless of task difficulty. Anxiety impacts both verbal and spatial processes, as described by correlations between anxiety and performance impairment, albeit the effect on spatial WM is consistent across load. Demanding WM tasks may exert top-down control over higher-order cortical resources engaged by anxious apprehension, however high-load spatial WM may continue to experience additional competition from anxiety-related changes in spatial attention, resulting in impaired performance. By describing this disruption across task modalities, these findings inform current theories of emotion-cognition interactions and may facilitate development of clinical interventions that seek to target cognitive impairments associated with anxiety.
Yang, Shengchang; Wen, Di; Dong, Mei; Li, Dong; Sun, Donglei; Ma, Chunling; Cong, Bin
Acute and chronic exposure to opiate drugs impaired various types of memory processes. To date, there is no preventive treatment for opiate-induced memory impairment and the related mechanism is still unclear. CCK-8 is the most potent endogenous anti-opioid peptide and has been shown to exert memory-enhancing effect, but the effect of CCK-8 on morphine-induced memory impairment has not been reported. By using Morris water maze, we found that escape latency to the hidden platform in navigation test was not influenced, but performance in the probe test was seriously poor in morphine dependency mice. Amnesia induced by chronic morphine treatment was significantly alleviated by pre-treatment with CCK-8 (0.01, 0.1 and 1 μg, i.c.v.), and CCK-8 (0.1 and 1 μg, i.c.v.) treatment alone could improve performance in either navigation or probe test. Furthermore, Golgi-Cox staining analysis revealed that pre-treatment with CCK-8 (1 μg, i.c.v.) reversed spine density decreased in CA1 region of hippocampus in morphine dependency mice, and CCK-8 (1 μg, i.c.v.) alone obviously increased spine density in CA1. Our findings conclude spine density change in CA1 region of hippocampus may be the structural plasticity mechanism which is responsible for enhancing effect of CCK-8 on spatial reference memory. Therefore, CCK-8 could effectively improve memory impairment in morphine dependency mice.
Richards, Jason T.; Oman, Charles M.; Shebilske, Wayne L.; Beall, Andrew C.; Liu, Andrew; Natapoff, Alan
Human orientation requires one to remember and visualize spatial arrangements of landmarks from different perspectives. Astronauts have reported difficulties remembering relationships between environmental landmarks when imagined in arbitrary 3D orientations. The present study investigated the effects of strategy training on humans' 1) ability to infer their orientation from landmarks presented ahead and below, 2) performance when subsequently learning a different array, and 3) retention of configurational knowledge over time. On the first experiment day, 24 subjects were tested in a virtual cubic chamber in which a picture of an animal was drawn on each wall. Through trial-by-trial exposures, they had to memorize the spatial relationships among the six pictures around them and learn to predict the direction to a specific picture when facing any view direction, and in any roll orientation. Half of the subjects ("strategy group") were taught methods for remembering picture groupings, while the remainder received no such training ("control group"). After learning one picture array, the procedure was repeated in a second. Accuracy (% correct) and response time learning curves were measured. Performance for the second array and configurational memory of both arrays were also retested 1, 7, and 30 days later. Results showed that subjects "learned how to learn" this generic 3D spatial memory task regardless of their relative orientation to the environment, that ability and configurational knowledge was retained for at least a month, that figure rotation ability and field independence correlate with performance, and that teaching subjects specific strategies in advance significantly improves performance. Training astronauts to perform a similar generic 3D spatial memory task, and suggesting strategies in advance, may help them orient in three dimensions.
Terunuma, Miho; Revilla-Sanchez, Raquel; Quadros, Isabel M; Deng, Qiudong; Deeb, Tarek Z; Lumb, Michael; Sicinski, Piotr; Haydon, Philip G; Pangalos, Menelas N; Moss, Stephen J
Cognitive dysfunction is a common symptom in many neuropsychiatric disorders and directly correlates with poor patient outcomes. The majority of prolonged inhibitory signaling in the brain is mediated via GABAB receptors (GABABRs), but the molecular function of these receptors in cognition is ill defined. To explore the significance of GABABRs in neuronal activity and cognition, we created mice with enhanced postsynaptic GABABR signaling by mutating the serine 783 in receptor R2 subunit (S783A), which decreased GABABR degradation. Enhanced GABABR activity reduced the expression of immediate-early gene-encoded protein Arc/Arg3.1, effectors that are critical for long-lasting memory. Intriguingly, S783A mice exhibited increased numbers of excitatory synapses and surface AMPA receptors, effects that are consistent with decreased Arc/Arg3.1 expression. These deficits in Arc/Arg3.1 and neuronal morphology lead to a deficit in spatial memory consolidation. Collectively our results suggest a novel and unappreciated role for GABABR activity in determining excitatory neuronal architecture and spatial memory via their ability to regulate Arc/Arg3.1.
Wang, Rui; Zhang, Yu; Li, Jianguo; Zhang, Ce
β-amyloid (Aβ) deposition is considered partially responsible for cognitive dysfunction in Alzheimer's disease (AD). Recently, resveratrol has been reported to play a potential role as a neuroprotective biofactor by modulating Aβ pathomechanisms, including through anti-neuronal apoptotic, anti-oxidative stress, and anti-neuroinflammatory effects. In addition, SIRT1 has been demonstrated to modulate learning and memory function by regulating the expression of cAMP response binding protein (CREB), which involves in modulating the expression of SIRT1. However, whether resveratrol can alleviate Aβ-induced cognitive dysfunction, whether SIRT1 expression and CREB phosphorylation in the hippocampus are affected by Aβ, and whether resveratrol influences these effects remain unknown. In the present study, we used a hippocampal injection model in rats to investigate the effects of resveratrol on Aβ1-42-induced impairment of spatial learning, memory and synaptic plasticity as well as on alterations of SIRT1 expression and CREB phosphorylation. We found that resveratrol significantly reversed the water maze behavioral impairment and the attenuation of long-term potentiation (LTP) in area CA1 that were induced by hippocampal injection of Aβ1-42. Interestingly, resveratrol also prevented the Aβ1-42-induced reductions in SIRT1 expression and CREB phosphorylation in rat hippocampus. In conclusion, in rats, resveratrol protects neurons against Aβ1-42-induced disruption of spatial learning, memory and hippocampal LTP. The mechanisms underlying the neuroprotective effects may involve rescue of SIRT1 expression and CREB phosphorylation.
Zhao, Zhengqing; Li, Yanpeng; Chen, Haiyan; Huang, Liuqing; Zhao, Fei; Yu, Qiang; Xiang, Zhenghua; Zhao, Zhongxin
We aimed to investigate the effects of Xylaria nigripes (XN) extracts on the rapid eye movement sleep deprivation (REMSD)-induced memory impairment, and explore related mechanism. Male Sprague Dawley rats were randomly divided into 6 groups: cage control (CC)-NaCl group; tank control (TC)-NaCl group; sleep deprivation (SD)-NaCl group; CC-XN group; TC-XN group and SD-XN group. The rats were administered with intragastric XN and 0.9% of sodium chloride. SD group rats were deprived of REM sleep for 72 h. Morris water maze (MWM) was used to assess the effects of XN on spatial learning and memory. The expression of cAMP-response element binding protein (CREB) and p-CREB were also investigated in all groups. Result showed rats in SD-NaCl group had significantly longer mean escape latencies in finding the platform as compared to the control rats (p<0.05) in MWM test. The SD-NaCl group spent significantly less time in goal quadrant compared with the SD-XN group. REMSD and XN did not alter CREB expression in the hippocampus, while sleep deprivation resulted in reduced phosphorylation of CREB in the hippocampus, which was reversed by XN. XN mitigates spatial memory impairment induced by REMSD in rat. Phosphorylation of CREB in hippocampus might be one of the mechanisms.
Yamada, Kazuo; Furukawa, Satoshi; Iwasaki, Tsuneo; Ichitani, Yukio
Ethylcholine mustard aziridinium ion (AF64A) is a neurotoxic derivative of choline that produces not only long-term presynaptic cholinergic deficits, but also various memory deficits in rats similar to some characteristics observed in Alzheimer's disease patients. This study investigated whether nicotine (NCT) administration attenuated spatial learning deficits induced by intracerebroventricular AF64A treatment. AF64A (6 nmol/6 microl)-or saline (SAL)-treated rats were trained in Morris water maze task. NCT (0.025-0.25mg/kg) was subcutaneously injected 5 min before the training every day. The results showed that moderate dose (0.10mg/kg) of NCT attenuated AF64A-induced prolongation of escape latency. Furthermore, NCT dose-dependently recovered the AF64A-induced decrease of time spent in the target quadrant in the probe test. These results suggest that NCT improves AF64A-induced spatial memory deficits, and thus it is a potential therapeutic agent for the treatment of memory deficits in dementia.
Revilla-Sanchez, Raquel; Quadros, Isabel M.; Deng, Qiudong; Deeb, Tarek Z.; Lumb, Michael; Sicinski, Piotr; Haydon, Philip G.; Pangalos, Menelas N.
Cognitive dysfunction is a common symptom in many neuropsychiatric disorders and directly correlates with poor patient outcomes. The majority of prolonged inhibitory signaling in the brain is mediated via GABAB receptors (GABABRs), but the molecular function of these receptors in cognition is ill defined. To explore the significance of GABABRs in neuronal activity and cognition, we created mice with enhanced postsynaptic GABABR signaling by mutating the serine 783 in receptor R2 subunit (S783A), which decreased GABABR degradation. Enhanced GABABR activity reduced the expression of immediate-early gene-encoded protein Arc/Arg3.1, effectors that are critical for long-lasting memory. Intriguingly, S783A mice exhibited increased numbers of excitatory synapses and surface AMPA receptors, effects that are consistent with decreased Arc/Arg3.1 expression. These deficits in Arc/Arg3.1 and neuronal morphology lead to a deficit in spatial memory consolidation. Collectively our results suggest a novel and unappreciated role for GABABR activity in determining excitatory neuronal architecture and spatial memory via their ability to regulate Arc/Arg3.1. PMID:24431439
Chrosniak, L.D.; Smith, L.N.; McDonald, C.G.; Jones, B.F.; Flinn, J.M.
Ingestion of enhanced zinc can cause memory impairments and copper deficiencies. This study examined the effect of zinc supplementation, with and without copper, on two types of memory. Rats raised pre- and post-natally on 10 mg/kg ZnCO3 or ZnSO4 in the drinking water were tested in a fear-conditioning experiment at 11 months of age. Both zinc groups showed a maladaptive retention of fearful memories compared to controls raised on tap water. Rats raised on 10 mg/kg ZnCO3, 10 mg/kg ZnCO3 + 0.25 mg/kg CuCl2, or tap water, were tested for spatial memory ability at 3 months of age. Significant improvements in performance were found in the ZnCO3 + CuCl2 group compared to the ZnCO3 group, suggesting that some of the cognitive deficits associated with zinc supplementation may be remediated by addition of copper. ?? 2005 Elsevier B.V. All rights reserved.
Abareshi, Azam; Anaeigoudari, Akbar; Norouzi, Fatemeh; Shafei, Mohammad Naser; Khazaei, Majid
Introduction. Renin-angiotensin system has a role in inflammation and also is involved in many brain functions such as learning, memory, and emotion. Neuroimmune factors have been proposed as the contributors to the pathogenesis of memory impairments. In the present study, the effect of captopril on spatial memory and synaptic plasticity impairments induced by lipopolysaccharide (LPS) was investigated. Methods. The rats were divided and treated into control (saline), LPS (1 mg/kg), LPS-captopril (LPS-Capto; 50 mg/kg captopril before LPS), and captopril groups (50 mg/kg) before saline. Morris water maze was done. Long-term potentiation (LTP) from CA1 area of hippocampus was assessed by 100 Hz stimulation in the ipsilateral Schaffer collateral pathway. Results. In the LPS group, the spent time and traveled path to reach the platform were longer than those in the control, while, in the LPS-Capto group, they were shorter than those in the LPS group. Moreover, the slope and amplitude of field excitatory postsynaptic potential (fEPSP) decreased in the LPS group, as compared to the control group, whereas, in the LPS-Capto group, they increased compared to the LPS group. Conclusion. The results of the present study showed that captopril improved the LPS-induced memory and LTP impairments induced by LPS in rats. Further investigations are required in order to better understand the exact responsible mechanism(s). PMID:27830176
Kilicaslan, Alper; Belviranli, Muaz; Okudan, Nilsel; Nurullahoglu Atalik, Esra
Volatile anesthetics are known to disturb the spatial memory in aged rodents, but there is insufficient information on their effects on young adult rodents. The aim of this study was to compare the effects of single and repeated exposure to desflurane and sevoflurane on spatial learning and memory functions in young adult mice. Balb/c mice (2 months old) were randomly divided into six equal groups (n = 8). The groups with single inhalation were exposed to 3.3% sevoflurane or 7.8% desflurane or vehicle gas for 4 h, respectively. The groups with repeated inhalation were exposed to 3.3% sevoflurane or 7.8% desflurane or vehicle gas for 2 h a day during 5 consecutive days. Spatial learning and memory were tested in the Morris water maze 24 h after exposure. In the learning phase, the parameters associated with finding the hidden platform and swimming speed, and in the memory phase, time spent in the target quadrant and the adjacent quadrants, were assessed and compared between the groups. In the 4-day learning process, there was no significant difference between the groups in terms of mean latency to platform, mean distance traveled and average speed (P > 0.05). During the memory-test phase, all mice exhibited spatial memory, but there was no significant difference between the groups in terms of time spent in the target quadrant (P > 0.05). Sevoflurane and desflurane anesthesia did not impair acquisition learning and retention memory in young adult mice.
Chen, Ning-Ning; Luo, Dan-Ju; Yao, Xiu-Qing; Yu, Cong; Wang, Yi; Wang, Qun; Wang, Jian-Zhi; Liu, Gong-Ping
Pesticides are widely used in agriculture, and epidemiological studies suggest that pesticide exposure is a risk factor for Alzheimer's disease (AD), but the mechanisms are elusive. Here, we studied the effects of pesticide exposure on the cognitive ability and the underlying mechanisms in rats. Deltamethrin and carbofuran were administered respectively into the rats once a day for 28 days by gavage. We found that pesticide exposure induced spatial learning and memory deficits with a simultaneous decrease of N-methyl-D-aspartate receptor 1, synaptophysin, and synapsin I, all of which are memory-related synaptic proteins. Pesticide exposure also induced tau hyperphosphorylation at multiple AD-related phosphorylation sites with activation of glycogen synthase kinase-3β and inhibition of protein phosphatase-2A. Additionally, neuron loss in the hippocampus and cortex was observed upon administration of the pesticides. These results indicate that the pesticides exposure could induce AD-like pathology and cognitive abnormality in rats.
Quinn, J G
The influential model of verbal working memory (WM) introduced by Baddeley and Hitch (Recent advances in learning and motivation. Academic, New York, 1974) comprised three interacting component parts; an executive controller and two subservient systems. The two subservient systems, one underpinning verbal processing and the other underpinning visual processing are themselves subdivided. In the verbal system, a passive phonological store is maintained by an active phonological loop, which is able to rehearse the material in the passive store. The visual working memory system has traditionally been thought of as having a similar architecture with a passive visual store being maintained by an active store, which codes in terms of movement over space. The paper discusses the evidence for this relationship in visuo-spatial WM and concludes that the architecture does not fit well with the experimental literature. A direction for future research is suggested.
Kessels, Roy P C; Nys, Gudrun M S; Brands, Augustina M A; van den Berg, Esther; Van Zandvoort, Martine J E
This study examines the applicability of the modified Location Learning Test (mLLT) as a test of spatial memory in neuropsychological patients. Three groups of participants were examined: stroke patients, patients with diabetes mellitus and healthy participants (N=411). Three error measures were computed, the Total Score (index of overall performance), the Learning Index (the learning curve over subsequent trials) and the Delayed Recall Score, measuring decay over time. The Learning Index was the most sensitive measure, showing differences between the three groups as well as lateralization effects within the stroke group. Also, the mLLT correlated significantly with the Rey Auditory Verbal Learning Test, as well as with age and education level. Regression-based normative data were computed based on the healthy participants. In all, the mLLT appears to be a sensitive and valid test for the detection of object-location memory impairments in clinical groups.
Gutierrez, Arnold; Jablonski, Sarah A; Amos-Kroohs, Robyn M; Barnes, Anna C; Williams, Michael T; Vorhees, Charles V
Severe stress potentiates methamphetamine (MA) neurotoxicity. However, whether moderate stress increases or decreases the neurotoxic effects of MA is unknown. We assessed the effects of MA (4 × 10 mg/kg at 2 h intervals) in combination with prior barren-cage housing in adult male Sprague-Dawley rats on monoamines and glial fibrillary acid protein (GFAP) in one cohort and spatial learning and memory in the Morris water maze in another cohort. MA reduced dopamine (DA) and serotonin (5-HT) in the neostriatum and nucleus accumbens, 5-HT in the hippocampus, and increased GFAP in neostriatum and nucleus accumbens compared with saline controls. In neostriatum, barren-cage housing protected against MA-induced increases in GFAP, but it did not prevent DA and 5-HT reductions, although it did increase hippocampal norepinephrine. MA impaired spatial learning during acquisition, reversal, and shift phases and impaired reference memory on reversal and shift probe trials. Barren-cage housing enhanced performance during acquisition but not during reversal or shift or on probe trials. The data indicate that prior barren-cage housing moderates MA-induced neostriatal astrogliosis and initial spatial learning, but has no protective effect when the platform is smaller and relocated and therefore requires cognitive flexibility in relearning.
Kempadoo, Kimberly A.; Mosharov, Eugene V.; Choi, Se Joon; Sulzer, David; Kandel, Eric R.
Dopamine neurotransmission in the dorsal hippocampus is critical for a range of functions from spatial learning and synaptic plasticity to the deficits underlying psychiatric disorders such as attention-deficit hyperactivity disorder. The ventral tegmental area (VTA) is the presumed source of dopamine in the dorsal hippocampus. However, there is a surprising scarcity of VTA dopamine axons in the dorsal hippocampus despite the dense network of dopamine receptors. We have explored this apparent paradox using optogenetic, biochemical, and behavioral approaches and found that dopaminergic axons and subsequent dopamine release in the dorsal hippocampus originate from neurons of the locus coeruleus (LC). Photostimulation of LC axons produced an increase in dopamine release in the dorsal hippocampus as revealed by high-performance liquid chromatography. Furthermore, optogenetically induced release of dopamine from the LC into the dorsal hippocampus enhanced selective attention and spatial object recognition via the dopamine D1/D5 receptor. These results suggest that spatial learning and memory are energized by the release of dopamine in the dorsal hippocampus from noradrenergic neurons of the LC. The present findings are critical for identifying the neural circuits that enable proper attention selection and successful learning and memory. PMID:27930324
Kempadoo, Kimberly A; Mosharov, Eugene V; Choi, Se Joon; Sulzer, David; Kandel, Eric R
Dopamine neurotransmission in the dorsal hippocampus is critical for a range of functions from spatial learning and synaptic plasticity to the deficits underlying psychiatric disorders such as attention-deficit hyperactivity disorder. The ventral tegmental area (VTA) is the presumed source of dopamine in the dorsal hippocampus. However, there is a surprising scarcity of VTA dopamine axons in the dorsal hippocampus despite the dense network of dopamine receptors. We have explored this apparent paradox using optogenetic, biochemical, and behavioral approaches and found that dopaminergic axons and subsequent dopamine release in the dorsal hippocampus originate from neurons of the locus coeruleus (LC). Photostimulation of LC axons produced an increase in dopamine release in the dorsal hippocampus as revealed by high-performance liquid chromatography. Furthermore, optogenetically induced release of dopamine from the LC into the dorsal hippocampus enhanced selective attention and spatial object recognition via the dopamine D1/D5 receptor. These results suggest that spatial learning and memory are energized by the release of dopamine in the dorsal hippocampus from noradrenergic neurons of the LC. The present findings are critical for identifying the neural circuits that enable proper attention selection and successful learning and memory.
McQuail, Joseph A; Nicolle, Michelle M
Fischer 344 × Brown Norway F1 (F344 × BN-F1) hybrid rats express greater longevity with improved health relative to aging rodents of other strains; however, few behavioral reports have thoroughly evaluated cognition across the F344 × BN-F1 lifespan. Consequently, this study evaluated spatial reference memory in F344 × BN-F1 rats at 6, 18, 24, or 28 months of age in the Morris water maze. Reference memory decrements were observed between 6 and 18 months and 18 and 24 months. At 28 months, spatial learning was not worse than 24 months, but swim speed was significantly slower. Reliable individual differences revealed that ∼50% of 24- to 28-month-old rats performed similarly to 6 months, whereas others were spatial learning impaired. Aged rats were impaired at learning within daily training sessions but not impaired at retaining information between days of training. Aged rats were also slower to learn to escape onto the platform, regardless of strategy. In summary, these data clarify the trajectory of cognitive decline in aging F344 × BN-F1 rats and elucidate relevant behavioral parameters.
Nilsson, Jonna; Ferrier, I Nicol; Coventry, Kenny; Bester, Andre; Finkelmeyer, Andreas
A parieto-medial temporal pathway is thought to underlie spatial navigation in humans. fMRI was used to assess the role of this pathway, including the hippocampus, in the cognitive processes likely to underlie navigation based on environmental cues. Participants completed a short-term spatial memory task in virtual space, which required no navigation but involved the recognition of a target location from a foil location based on environmental landmarks. The results showed that spatial memory retrieval based on environmental landmarks was indeed associated with increased signal in regions of the parieto-medial temporal pathway, including the superior parietal cortex, the retrosplenial cortex, and the lingual gyrus. However, the hippocampus demonstrated a signal decrease below the fixation baseline during landmark-based retrieval, whereas there was no signal change from baseline during retrieval based on viewer position. In a discussion of the origins of such negative BOLD response in the hippocampus, we consider both a suppression of default activity and an increase in activity without a corresponding boost in CBF as possible mechanisms.
Street, Whitney N; Wang, Ranxiao Frances
Previous research showed competition among reference frames in spatial attention and language. The present studies developed a new distribution analysis to examine reference frame interactions in spatial memory. Participants viewed virtual arrays of colored pegs and were instructed to remember them either from their own perspective or from the perspective aligned with the rectangular floor. Then they made judgments of relative directions from their respective encoding orientation. Those taking the floor-axis perspective showed systematic bias in the signed errors toward their egocentric perspective, while those taking their own perspective showed no systematic bias, both for random and symmetrical object arrays. The bias toward the egocentric perspective was observed when learning a real symmetr