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1

Neural Associations of the Early Retinotopic Cortex with the Lateral Occipital Complex during Visual Perception  

PubMed Central

Previous studies have demonstrated that the early retinotopic cortex (ERC, i.e., V1/V2/V3) is highly associated with the lateral occipital complex (LOC) during visual perception. However, it remains largely unclear how to evaluate their associations in quantitative way. The present study tried to apply a multivariate pattern analysis (MVPA) to quantify the neural activity in ERC and its association with that of the LOC when participants saw visual images. To this end, we assessed whether low-level visual features (Gabor features) could predict the neural activity in the ERC and LOC according to a voxel-based encoding model (VBEM), and then quantified the association of the neural activity between these regions by using an analogical VBEM. We found that the Gabor features remarkably predicted the activity of the ERC (e.g., the predicted accuracy was 52.5% for a participant) instead of that of the LOC (4.2%). Moreover, the MVPA approach can also be used to establish corresponding relationships between the activity patterns in the LOC and those in the ERC (64.2%). In particular, we found that the integration of the Gabor features and LOC visual information could dramatically improve the ‘prediction’ of ERC activity (88.3%). Overall, the present study provides new evidences for the possibility of quantifying the association of the neural activity between the regions of ERC and LOC. This approach will help to provide further insights into the neural substrates of the visual processing. PMID:25251083

Liang, Bishan; Liu, Bo; Liu, Ming; Huang, Ruiwang

2014-01-01

2

Functional Organization of Human Visual Cortex in Occipital Polymicrogyria  

E-print Network

Functional Organization of Human Visual Cortex in Occipital Polymicrogyria Serge O. Dumoulin,1 patients with epilepsy and bilateral parasagittal occipital polymicrogyri were studied. They all had normal development; functional magnetic resonance imaging (fMRI); retinotopic mapping; vision; visual cortex; V1

Dumoulin, Serge O.

3

Language processing in the occipital cortex of congenitally blind adults  

E-print Network

severe brain dam- age to the left-hemisphere language regions develop language abilities withinLanguage processing in the occipital cortex of congenitally blind adults Marina Bednya,b,1 , Alvaro in the left frontal and temporal cortex that are uniquely capable of language processing. However

Saxe, Rebecca

4

Abnormalities in the Development of the Tectal Projection from Transplants of Embryonic Occipital Cortex Placed in the Damaged Occipital Cortex of Newborn Rats  

Microsoft Academic Search

We have examined the degree of precision in the topographic arrangement of the tectal projection developed by homotopic transplants of embryonic occipital cortex and tried to determine whether the development of the corticotectal projection is exclusively dependent on environmental cues or is also controlled by intrinsic factors. Transplants of embryonic (E16) occipital cortex were grafted into various areas of the

Afsaneh Gaillard; Jérôme Létang; Isabelle Frappé; Michel Roger

1997-01-01

5

Representation of the visual field in the occipital striate cortex.  

PubMed Central

The representation of the field of vision in the human striate cortex is based on the Holmes map in which about 25% of the surface area of the striate cortex is allocated to the central 15 degrees of vision. Following the introduction of computed tomography of the brain, the accuracy of the Holmes map was apparently confirmed by clinical/radiological correlation, but a revision has been proposed by Horton and Hoyt based on a magnetic resonance imaging study of three patients with visual field defects due to striate lesions. They propose that the central cortical representation of vision occupies a much larger area. This study reviews the perimetric and imaging findings in a larger series of patients with striate cortical disease and provides support for the revised representation. The clinical phenomenon of macular sparing and its relation to representation of the macula at the occipital pole is also discussed. Images PMID:8148333

McFadzean, R; Brosnahan, D; Hadley, D; Mutlukan, E

1994-01-01

6

1 Introduction WHENTHE visual cortex in the occipital lobe is electrically  

E-print Network

1 Introduction WHENTHE visual cortex in the occipital lobe is electrically stimulated, human to develop a prosthesis for the blind that might be of value in reading and mobility (BRINDLEYand LEWIN,1968 patients who were undergoing occipital craniotomies under local anaesthesia for excision of epileptic foci

Loeb, Gerald E.

7

Language processing in the occipital cortex of congenitally blind  

E-print Network

Humans are thought to have evolved brain regions in the left frontal and temporal cortex that are uniquely capable of language processing. However, congenitally blind individuals also activate the visual cortex in some ...

Bedny, Marina

8

Changing Human Visual Field Organization from Early Visual to Extra-Occipital Cortex  

PubMed Central

Background The early visual areas have a clear topographic organization, such that adjacent parts of the cortical surface represent distinct yet adjacent parts of the contralateral visual field. We examined whether cortical regions outside occipital cortex show a similar organization. Methodology/Principal Findings The BOLD responses to discrete visual field locations that varied in both polar angle and eccentricity were measured using two different tasks. As described previously, numerous occipital regions are both selective for the contralateral visual field and show topographic organization within that field. Extra-occipital regions are also selective for the contralateral visual field, but possess little (or no) topographic organization. A regional analysis demonstrates that this weak topography is not due to increased receptive field size in extra-occipital areas. Conclusions/Significance A number of extra-occipital areas are identified that are sensitive to visual field location. Neurons in these areas corresponding to different locations in the contralateral visual field do not demonstrate any regular or robust topographic organization, but appear instead to be intermixed on the cortical surface. This suggests a shift from processing that is predominately local in visual space, in occipital areas, to global, in extra-occipital areas. Global processing fits with a role for these extra-occipital areas in selecting a spatial locus for attention and/or eye-movements. PMID:17505546

Jack, Anthony I.; Patel, Gaurav H.; Astafiev, Serguei V.; Snyder, Abraham Z.; Akbudak, Erbil; Shulman, Gordon L.; Corbetta, Maurizio

2007-01-01

9

Optic fiber development between dual transplants of retina and superior colliculus placed in the occipital cortex  

Microsoft Academic Search

Fetal rat retina was excised from donor rats at 15 days of gestation and transplanted to the occipital cortex of neonatal host rats in combination with and adjacent to: 1) the appropriate portion of the superior colliculus to serve as a specific target tissue in an attempt to stimulate an outgrowth of optic fibers from the isolated retinal transplant; 2)

Murray A. Matthews; Leigh C. West

1982-01-01

10

Activity-dependent development of spontaneous bioelectric activity in organotypic cultures of rat occipital cortex  

Microsoft Academic Search

The development of spontaneous bioelectric activity (SBA) in organotypic tissue cultures (OTCs) from rat occipital cortex was studied by means of extracellular recording techniques in OTCs grown normally for 6–51 days in vitro (DIV), and in OTCs in which SBA had been silenced from DIV 4 on for 2 to 3 weeks by elevating the Mg2+ levels in the growth

Diego Echevarr??a; Klaus Albus

2000-01-01

11

Retinal abnormalities in human albinism translate into a reduction of grey matter in the occipital cortex  

E-print Network

Retinal abnormalities in human albinism translate into a reduction of grey matter in the occipital London, UK Keywords: albinism, foveal hypoplasia, visual cortex, voxel-based morphometry Abstract Albinism is a genetic condition associated with abnormalities of the visual system. Defects in melanin

Morland, Antony

12

Role of the medial parieto-occipital cortex in the control of reaching and grasping movements.  

PubMed

The medial parieto-occipital cortex is a central node in the dorsomedial visual stream. Recent physiological studies in the macaque monkey have demonstrated that the medial parieto-occipital cortex contains two areas, the visual area V6 and the visuomotor area V6A. Area V6 is a retinotopically organized visual area that receives form and motion information directly from V1 and is heavily connected with the other areas of the dorsal visual stream, including V6A. Area V6A is a bimodal visual/somatosensory area that elaborates visual information such as form, motion and space suitable for the control of both reaching and grasping movements. Somatosensory and skeletomotor activities in V6A affect the upper limbs and involve both the transport phase of reaching and grasping movements. Finally, V6A is strongly and reciprocally connected with the dorsal premotor cortex controlling arm movements. The picture emerging from these data is that the medial parieto-occipital cortex is well equipped to control both proximal and distal movements in the online visuomotor guidance of prehension. In agreement with this view, selective V6A lesions in monkey produce misreaching and misgrasping with the arm contralateral to the lesion in visually guided movements. These deficits are similar to those observed in optic ataxia patients and suggest that human and monkey superior parietal lobules are homologous structures, and that optic ataxia syndrome is the result of the lesion of a 'human' area V6A. PMID:14517595

Galletti, Claudio; Kutz, Dieter F; Gamberini, Michela; Breveglieri, Rossella; Fattori, Patrizia

2003-11-01

13

Normal and 6-aminonicotinamide impaired development of capillarization in occipital cortex of rat  

Microsoft Academic Search

During different embryonic and postnatal stages, 6-aminonicotinamide (6-AN) was administered to Wistar albino rats. The capillarization of the occipital cortex has been examined morphometrically. A 6-AN-vulnerable stage of prenatal development was found, which lasted to the 19th prenatal day and which only partly corresponds to the so-called ‘critical stage’ of capillary sprouting (Kapillarsprossung). Capillary sprouting was not impaired by 6-AN

Alexander Rauchfuss

1978-01-01

14

Object-Related Activity Revealed by Functional Magnetic Resonance Imaging in Human Occipital Cortex  

Microsoft Academic Search

The stages of integration leading from local feature analysis to object recognition were explored in human visual cortex by using the technique of functional magnetic resonance imaging. Here we report evidence for object-related activation. Such activation was located at the lateral-posterior aspect of the occipital lobe, just abutting the posterior aspect of the motion-sensitive area MT\\/V5, in a region termed

R. Malach; J. B. Reppas; R. R. Benson; K. K. Kwong; H. Jiang; W. A. Kennedy; P. J. Ledden; T. J. Brady; B. R. Rosen; R. B. H. Tootell

1995-01-01

15

Impairment of visual perception and visual short term memory scanning by transcranial magnetic stimulation of occipital cortex  

Microsoft Academic Search

Transcranial magnetic stimulation (TMS) of occipital cortex was performed using a magneto-electric stimulator with a maximum output of 2 Tesla in 24 normal volunteers. The identification of trigrams, presented for 14 ms in horizontal or vertical arrays was significantly impaired when the visual stimulus preceded the occipital magnetic shock by 40 to 120 ms. The extent of impairment was related

G. Beckers; V. Hömberg

1991-01-01

16

Enhancement of Central Noradrenaline Release during Development Alters the Packing Density of Neurons in the Rat Occipital Cortex  

Microsoft Academic Search

The effect of chronic yohimbine treatment early in life on packing density of neurons was evaluated in the occipital cortex of young rats. Yohimbine administration to pups between days 5 and 16 of postnatal life (2.5 mg\\/kg\\/day i.p.) resulted at 45 days of age in significantly higher neuronal density in layers II–V of the occipital cortex, the effect being more

Samuel Ruiz; Victor Fernández; Jorge Belmar; Alejandro Hernández; Hernán Pérez; Miguel Sanhueza-Tsutsumi; Sergio Alarcón; Rubén Soto-Moyano

1997-01-01

17

LOC689986, a unique gene showing specific expression in restricted areas of the rodent neocortex  

PubMed Central

Background The neocortex is a highly specialised and complex brain structure, involved in numerous tasks, ranging from processing and interpretation of somatosensory information, to control of motor functions. The normal function linked to distinct neocortical areas might involve control of highly specific gene expression, and in order to identify such regionally enriched genes, we previously analysed the global gene expression in three different cortical regions (frontomedial, temporal and occipital cortex) from the adult rat brain. We identified distinct sets of differentially expressed genes. One of these genes, namely the hypothetical protein LOC689986 (LOC689986), was of particular interest, due to an almost exclusive expression in the temporal cortex. Results Detailed analysis of LOC689986 in the adult rat brain confirmed the expression in confined areas of parieto-temporal cortex, and revealed highly specific expression in layer 4 of the somatosensory cortex, with sharp borders towards the neighbouring motor cortex. In addition, LOC689986 was found to be translated in vivo, and was detected in the somatosensory cortex and in the Purkinje cells of the cerebellar cortex. The protein was present in neuronal dendrites and also in astrocyte cells. Finally, this unique gene is apparently specific for, and highly conserved in, the vertebrate lineage. Conclusions In this study, we have partially characterised the highly conserved LOC689986 gene, which is specific to the vertebrate linage. The gene displays a distinct pattern of expression in layer 4 of the somatosensory cortex, and areas of the parieto-temporal cortex in rodents. PMID:23844656

2013-01-01

18

Development of neuropeptide Y (NPY) immunoreactive neurons in the rat occipital cortex: A combined immunohistochemical-autoradiographic study  

Microsoft Academic Search

The postnatal development of neuropeptide Y (NPY)-immunoreactive neurons, previously labeled with (3H)thymidine on embryonic days E14-E21, has been studied in the rat occipital cortex. Immunohistochemistry combined with autoradiography showed evidence of a modified inside-out pattern of maturation. NPY-neurons are generated between E14 and E20 and are found in layers II-VI of the cortex and the subcortical white matter. NPY neurons

Marion E. Cavanagh; John G. Parnavelas

1990-01-01

19

Repetition suppression for speech processing in the associative occipital and parietal cortex of congenitally blind adults.  

PubMed

In the congenitally blind (CB), sensory deprivation results in cross-modal plasticity, with visual cortical activity observed for various auditory tasks. This reorganization has been associated with enhanced auditory abilities and the recruitment of visual brain areas during sound and language processing. The questions we addressed are whether visual cortical activity might also be observed in CB during passive listening to auditory speech and whether cross-modal plasticity is associated with adaptive differences in neuronal populations compared to sighted individuals (SI). We focused on the neural substrate of vowel processing in CB and SI adults using a repetition suppression (RS) paradigm. RS has been associated with enhanced or accelerated neural processing efficiency and synchronous activity between interacting brain regions. We evaluated whether cortical areas in CB were sensitive to RS during repeated vowel processing and whether there were differences across the two groups. In accordance with previous studies, both groups displayed a RS effect in the posterior temporal cortex. In the blind, however, additional occipital, temporal and parietal cortical regions were associated with predictive processing of repeated vowel sounds. The findings suggest a more expanded role for cross-modal compensatory effects in blind persons during sound and speech processing and a functional transfer of specific adaptive properties across neural regions as a consequence of sensory deprivation at birth. PMID:23717628

Arnaud, Laureline; Sato, Marc; Ménard, Lucie; Gracco, Vincent L

2013-01-01

20

Activation of the occipital cortex and deactivation of the default mode network during working memory in the early blind.  

PubMed

Although blind people heavily depend on working memory to manage daily life without visual information, it is not clear yet whether their working memory processing involves functional reorganization of the memory-related cortical network. To explore functional reorganization of the cortical network that supports various types of working memory processes in the early blind, we investigated activation differences between 2-back tasks and 0-back tasks using fMRI in 10 congenitally blind subjects and 10 sighted subjects. We used three types of stimulus sequences: words for a verbal task, pitches for a non-verbal task, and sound locations for a spatial task. When compared to the sighted, the blind showed additional activations in the occipital lobe for all types of stimulus sequences for working memory and more significant deactivation in the posterior cingulate cortex of the default mode network. The blind had increased effective connectivity from the default mode network to the left parieto-frontal network and from the occipital cortex to the right parieto-frontal network during the 2-back tasks than the 0-back tasks. These findings suggest not only cortical plasticity of the occipital cortex but also reorganization of the cortical network for the executive control of working memory. PMID:21338547

Park, Hae-Jeong; Chun, Ji-Won; Park, Bumhee; Park, Haeil; Kim, Joong Il; Lee, Jong Doo; Kim, Jae-Jin

2011-05-01

21

Functional MRI activity in the thalamus and occipital cortex of anesthetized dogs induced by monocular and binocular stimulation.  

PubMed Central

The neuroanatomy of the mammalian visual system has received considerable attention through electrophysiological study of cats and non-human primates, and through neuroimaging of humans. Canine neuroanatomy, however, has received much less attention, limiting our understanding of canine vision and visual pathways. As an early step in applying blood oxygenation level dependant (BOLD) functional magnetic resonance imaging (fMRI) for veterinary use, we compared visual activity in the thalamus and occipital cortex of anesthetized dogs presented with binocular and monocular visual stimuli. Activity in the left and right thalamus and occipital cortex during monocular stimulation was also compared. Six beagles were presented with a vertical grating visual stimulus and scanned at 4 Tesla. Each dog was scanned twice under each of 3 anesthetic protocols (isoflurane, propofol, and fentanyl/midazolam). We found: 1) significant BOLD activation in the lateral geniculate nucleus (LGN) of the thalamus and the occipital cortex; 2) a significantly larger area of activation in the LGN during monocular stimulation than during binocular stimulation; and 3) that activity in the hemisphere contralateral to the stimulus was not significantly greater than that ipsilateral to it. Images Figure 1. PMID:11480525

Willis, C K; Quinn, R P; McDonell, W M; Gati, J; Partlow, G; Vilis, T

2001-01-01

22

Intracerebral electrical stimulation of a face-selective area in the right inferior occipital cortex impairs individual face discrimination.  

PubMed

During intracerebral stimulation of the right inferior occipital cortex, a patient with refractory epilepsy was transiently impaired at discriminating two simultaneously presented photographs of unfamiliar faces. The critical electrode contact was located in the most posterior face-selective brain area of the human brain (right "occipital face area", rOFA) as shown both by low- (ERP) and high-frequency (gamma) electrophysiological responses as well as a face localizer in fMRI. At this electrode contact, periodic visual presentation of 6 different faces by second evoked a larger electrophysiological periodic response at 6 Hz than when the same face identity was repeated at the same rate. This intracerebral EEG repetition suppression effect was markedly reduced when face stimuli were presented upside-down, a manipulation that impairs individual face discrimination. These findings provide original evidence for a causal relationship between the face-selective right inferior occipital cortex and individual face discrimination, independently of long-term memory representations. More generally, they support the functional value of electrophysiological repetition suppression effects, indicating that these effects can be used as an index of a necessary neural representation of the changing stimulus property. PMID:24936686

Jonas, Jacques; Rossion, Bruno; Krieg, Julien; Koessler, Laurent; Colnat-Coulbois, Sophie; Vespignani, Hervé; Jacques, Corentin; Vignal, Jean-Pierre; Brissart, Hélène; Maillard, Louis

2014-10-01

23

Alfred Walter Campbell and the visual functions of the occipital cortex.  

PubMed

In his pioneering cytoarchitectonic studies of the human brain, Alfred Walter Campbell identified two structurally different areas in the occipital lobes and assigned two different kinds of visual functions to them. The first area, the visuosensory, was essentially on the mesial surface of the calcarine fissure. It was the terminus of nervous impulses generated in the retina and was where simple visual sensations arose. The second area, the visuopsychic, which surrounded or invested the first, was where sensations were interpreted and elaborated into visual perceptions. I argue that Campbell's distinction between the two areas was the starting point for the eventual differentiation of areas V1-V5. After a brief outline of Campbell's early life and education in Australia and of his Scottish medical education and early work as a pathologist at the Lancashire County Lunatic Asylum at Rainhill near Liverpool, I summarise his work on the human brain. In describing the structures he identified in the occipital lobes, I analyse the similarities and differences between them and the related structures identified by Joseph Shaw Bolton. I conclude by proposing some reasons for how that work came to be overshadowed by the later studies of Brodmann and for the more general lack of recognition given Campbell and his work. Those reasons include the effect of the controversies precipitated by Campbell's alliance with Charles Sherrington over the functions of the sensory and motor cortices. PMID:23218905

Macmillan, Malcolm

2014-07-01

24

An ultrastructural analysis of the development of foetal rat retina transplanted to the occipital cortex, a site lacking appropriate target neurons for optic fibres  

Microsoft Academic Search

Summary Foetal retina was removed from donor rats at 15 days of gestation and transplanted to the occipital cortex of neonatal host rats. The purpose of this procedure was to examine the development of retinal neurons and photoreceptors, and document synaptic patterns during maturation of the transplanted retina in an environment lacking a normal target for optic axons. Host animals

M. A. Matthews; L. C. West; R. V. Riccio

1982-01-01

25

The Role of Spared Calcarine Cortex and Lateral Occipital Cortex in the Responses of Human Hemianopes to Visual Motion  

Microsoft Academic Search

Some patients, who are rendered perimetrically blind in one hemifield by cortical lesions, nevertheless exhibit residual visual capacities within their field defects. The neural mechanism that mediates the residual visual responses has remained the topic of considerable debate. One explanation posits the subcortical visual pathways that bypass the primary visual cortex and innervate the extrastriate visual areas as the substrate

Antony B. Morland; Sandra Lê; Erin Carroll; Michael B. Hoffmann; Alidz Pambakian

2004-01-01

26

Development of neuropeptide Y (NPY) immunoreactive neurons in the rat occipital cortex: A combined immunohistochemical-autoradiographic study  

SciTech Connect

The postnatal development of neuropeptide Y (NPY)-immunoreactive neurons, previously labeled with (3H)thymidine on embryonic days E14-E21, has been studied in the rat occipital cortex. Immunohistochemistry combined with autoradiography showed evidence of a modified inside-out pattern of maturation. NPY-neurons are generated between E14 and E20 and are found in layers II-VI of the cortex and the subcortical white matter. NPY neurons from all these birthdates are overproduced at first, although cells generated at E16 produce the greatest excess, followed by E15 and E17. Some of these transient neurons are found in the wrong layer for their birthdates, and their elimination produces a more correct alignment at maturity. However, most of the NPY neurons that survive are generated at E17, and these cells are found throughout layers II-VI with a preponderance in layer VI. This evidence is strongly suggestive of cell death rather than merely cessation of production of NPY.

Cavanagh, M.E.; Parnavelas, J.G. (University College London (England))

1990-07-22

27

An integrated face-body representation in the fusiform gyrus but not the lateral occipital cortex.  

PubMed

Faces and bodies are processed by distinct category-selective brain areas. Neuroimaging studies have so far presented isolated faces and headless bodies, and therefore little is known on whether and where faces and headless bodies are grouped together to one object, as they appear in the real world. The current study examined whether a face presented above a body are represented as two separate images or as an integrated face-body representation in face and body-selective brain areas by employing a fMRI competition paradigm. This paradigm has been shown to reveal higher fMRI response to sequential than simultaneous presentation of multiple stimuli (i.e., the competition effect), indicating competitive interactions among simultaneously presented multiple stimuli. We therefore hypothesized that if a face above a body is integrated to an image of a person whereas a body above a face is represented as two separate objects, the competition effect will be larger for the latter than the former. Consistent with our hypothesis, our findings reveal a competition effect when a body is presented above a face, but not when a face is presented above a body, suggesting that a body above a face is represented as two separate objects whereas a face above a body is represented as an integrated image of a person. Interestingly, this integration of a face and a body to an image of a person was found in the fusiform, but not the lateral-occipital face and body areas. We conclude that faces and bodies are processed separately at early stages and are integrated to a unified image of a person at mid-level stages of object processing. PMID:24702456

Bernstein, Michal; Oron, Jonathan; Sadeh, Boaz; Yovel, Galit

2014-11-01

28

rTMS of medial parieto-occipital cortex interferes with attentional reorienting during attention and reaching tasks.  

PubMed

Unexpected changes in the location of a target for an upcoming action require both attentional reorienting and motor planning update. In both macaque and human brain, the medial posterior parietal cortex is involved in both phenomena but its causal role is still unclear. Here we used on-line rTMS over the putative human V6A (pV6A), a reach-related region in the dorsal part of the anterior bank of the parieto-occipital sulcus, during an attention and a reaching task requiring covert shifts of attention and planning of reaching movements toward cued targets in space. We found that rTMS increased RTs to invalidly cued but not to validly cued targets during both the attention and reaching task. Furthermore, we found that rTMS induced a deviation of reaching endpoints toward visual fixation and that this deviation was larger for invalidly cued targets. The results suggest that reorienting signals are used by human pV6A area to rapidly update the current motor plan or the ongoing action when a behaviorally relevant object unexpectedly occurs in an unattended location. The current findings suggest a direct involvement of the action-related dorso-medial visual stream in attentional reorienting and a more specific role of pV6A area in the dynamic, on-line control of reaching actions. PMID:23647519

Ciavarro, Marco; Ambrosini, Ettore; Tosoni, Annalisa; Committeri, Giorgia; Fattori, Patrizia; Galletti, Claudio

2013-09-01

29

Differential development of high-level visual cortex correlates with category-specific recognition memory  

Microsoft Academic Search

High-level visual cortex in humans includes functionally defined regions that preferentially respond to objects, faces and places. It is unknown how these regions develop and whether their development relates to recognition memory. We used functional magnetic resonance imaging to examine the development of several functionally defined regions including object (lateral occipital complex, LOC)-, face ('fusiform face area', FFA; superior temporal

Dara G Ghahremani; S Whitfield-Gabrieli; Allan Reiss; Jennifer L Eberhardt; John D E Gabrieli; Kalanit Grill-Spector; Golijeh Golarai

2007-01-01

30

Occipital Alpha Activity during Stimulus Processing Gates the Information Flow to Object-Selective Cortex  

PubMed Central

Given the limited processing capabilities of the sensory system, it is essential that attended information is gated to downstream areas, whereas unattended information is blocked. While it has been proposed that alpha band (8–13 Hz) activity serves to route information to downstream regions by inhibiting neuronal processing in task-irrelevant regions, this hypothesis remains untested. Here we investigate how neuronal oscillations detected by electroencephalography in visual areas during working memory encoding serve to gate information reflected in the simultaneously recorded blood-oxygenation-level-dependent (BOLD) signals recorded by functional magnetic resonance imaging in downstream ventral regions. We used a paradigm in which 16 participants were presented with faces and landscapes in the right and left hemifields; one hemifield was attended and the other unattended. We observed that decreased alpha power contralateral to the attended object predicted the BOLD signal representing the attended object in ventral object-selective regions. Furthermore, increased alpha power ipsilateral to the attended object predicted a decrease in the BOLD signal representing the unattended object. We also found that the BOLD signal in the dorsal attention network inversely correlated with visual alpha power. This is the first demonstration, to our knowledge, that oscillations in the alpha band are implicated in the gating of information from the visual cortex to the ventral stream, as reflected in the representationally specific BOLD signal. This link of sensory alpha to downstream activity provides a neurophysiological substrate for the mechanism of selective attention during stimulus processing, which not only boosts the attended information but also suppresses distraction. Although previous studies have shown a relation between the BOLD signal from the dorsal attention network and the alpha band at rest, we demonstrate such a relation during a visuospatial task, indicating that the dorsal attention network exercises top-down control of visual alpha activity. PMID:25333286

Zumer, Johanna M.; Scheeringa, Rene; Schoffelen, Jan-Mathijs; Norris, David G.; Jensen, Ole

2014-01-01

31

Evidence for participation by object-selective visual cortex in scene category judgments.  

PubMed

Scene recognition is a core function of the visual system, drawing both on scenes' intrinsic global features, prominently their spatial properties, and on the identities of the objects scenes contain. Neuroimaging and neuropsychological studies have associated spatial property-based scene categorization with parahippocampal cortex, while processing of scene-relevant object information is associated with the lateral occipital complex (LOC), wherein activity patterns distinguish between categories of standalone objects and those embedded in scenes. However, despite the importance of objects to scene categorization and the role of LOC in processing them, damage or disruption to LOC that hampers object recognition has been shown to improve scene categorization. To address this paradox, we used functional magnetic resonance imaging (fMRI) to directly assess the contributions of LOC and the parahippocampal place area (PPA) to category judgments of indoor scenes that were devoid of objective identity signals. Observers were alternately cued to base judgments on scenes' objects or spatial properties. In both LOC and PPA, multivoxel activity patterns better decoded judgments based on their typically associated features: LOC more accurately decoded object-based judgments, while PPA more accurately decoded spatial property-based judgments. The cue contingency of LOC decoding accuracy indicates that it was not an outcome of feedback from judgments and is instead consistent with dependency of judgments on the output of object processing pathways in which LOC participates. PMID:25146577

Linsley, Drew; MacEvoy, Sean P

2014-01-01

32

Reduced repetition suppression in the occipital visual cortex during repeated negative Chinese personality-trait word processing.  

PubMed

Reduced neural activation have been consistently observed during repeated items processing, a phenomenon termed repetition suppression. The present study used functional magnetic resonance imaging (fMRI) to investigate whether and how stimuli of emotional valence affects repetition suppression by adopting Chinese personality-trait words as materials. Seventeen participants were required to read the negative and neutral Chinese personality-trait words silently. And then they were presented with repeated and novel items during scanning. Results showed significant repetition suppression in the inferior occipital gyrus only for neutral personality-trait words, whereas similar repetition suppression in the left inferior temporal gyrus and left middle temporal gyrus was revealed for both the word types. These results indicated common and distinct neural substrates during processing Chinese repeated negative and neutral personality-trait words. PMID:25251564

Qiao, Fuqiang; Zheng, Li; Li, Lin; Zhu, Lei; Wang, Qianfeng

2014-12-01

33

Phosphenes produced by electrical stimulation of human occipital cortex, and their application to the development of a prosthesis for the blind  

PubMed Central

1. To explore the feasibility of a visual prosthesis for the blind, human visual cortex has been stimulated during a series of surgical procedures on conscious volunteers undergoing other occipital lobe surgery. 2. Area no. 17 seems the most effective locus for such stimulation, at least in sighted or recently hemianopic patients. 3. Changes in electrode size and configuration, or in stimulus parameters, have little effect on subjective sensation. 4. Thresholds do vary depending on parameters, but not electrode size, and these effects have been studied. 5. Painful effects are associated with stimulation of the dura, but not of the calcarine artery and associated vessels. 6. Stimulation of a single electrode usually produces one phosphene, whose size ranges from tiny punctate sensations like `a star in the sky' up to a large coin at arm's length. Very large elongated phosphenes, like those seen by Brindley's second patient, have not been reported despite the number of patients, electrodes, and combinations of stimulus parameters tested. These large phosphenes may be an effect of prolonged blindness. 7. Stimulation substantially above threshold may produce a second conjugate phosphene, inverted about the horizontal meridian. 8. Stimulation of a single electrode may also produce multiple phosphenes with no differential threshold. 9. Chromatic effects and/or phosphene flicker may, or may not occur. This can vary from point to point on the same patient. 10. Phosphenes fade after 10-15 sec of continuous stimulation. 11. All phosphenes move proportionately with voluntary eye movements, within the accuracy of our mapping techniques. 12. Brightness modulation can easily be achieved by changing pulse amplitude. 13. The position of phosphenes in the visual field corresponds only roughly with expectations based on classical maps showing the projection of the visual field onto the cortex. 14. Patients can usually discriminate phosphenes produced by 1 mm2 electrodes on 3 mm centres, although this seems to be close to the limit of resolution. 15. Patterns of up to four phosphenes produced by four electrodes have been recognized. However, a variety of complex interactions have been reported. 16. Multiple phosphenes are co-planar, although patients are unable to estimate their distance. 17. Phosphenes appear immediately when stimulation is begun, and disappear immediately upon cessation of stimulation. 18. Future work must concentrate on blind volunteers to explore possible differences in subjective sensation produced after prolonged blindness, and to explore more complex pattern presentation which requires substantial periods of time with any given patient. ImagesPlate 1 PMID:4449074

Dobelle, W. H.; Mladejovsky, M. G.

1974-01-01

34

Shape Saliency Modulates Contextual Processing in the Human Lateral Occipital Complex  

E-print Network

in shape perception in the human brain. We investigated whether the human lateral occipital complex (LOC and grouping processes. That is, neural pop- ulations in the LOC encode context information when relevant information, its role in shape perception and its representation in the human brain. The present study used

Kourtzi, Zoe

35

Developmental exposure of rats to a reconstituted PCB mixture or aroclor 1254: effects on long-term potentiation and [3H]MK-801 binding in occipital cortex and hippocampus.  

PubMed

The central nervous system is one of the target organs for polychlorinated biphenyls (PCBs). We measured the effects of maternal exposure of Long-Evans rats to a mixture of PCB congeners reconstituted according to the pattern found in human breast milk (reconstituted mixture, RM) on long-term potentiation (LTP) in two brain regions. Exposure of the dams via food started 50 days prior to mating and was terminated at birth. In the first experiment, adult male and female offspring were exposed maternally to 40 mg/kg of the RM or the commercial mixture Aroclor 1254 (A1254). LTP and paired-pulse inhibition were measured in slices of the visual cortex. In addition, the binding of [3H]MK-801 to the N-methyl-D-aspartate (NMDA) receptor-ion channel as well as the [3H]muscimol binding to the GABA-A receptor in membrane preparations from the occipital cortex and hippocampus were determined. LTP as well as [3H]MK-801 binding were significantly reduced in the cortex following PCB exposure, while [3H]MK-801 binding in the hippocampus was not affected. In a succeeding experiment, LTP was determined in cortical and hippocampal slices from rats at postnatal days 10 to 20, following exposure to 0, 5, or 40 mg/kg of the RM. Cortical LTP was significantly affected by the RM while no effects were seen in hippocampal LTP. Taking the two experiments together, PCB exposure significantly reduced LTP, as well as [3H]MK-801 binding, in the cortex and had no effect in the hippocampus. The LTP deficits can only partly be related to the reduction of binding sites to the NMDA receptor; other PCB-induced neurochemical changes have to be assumed. PMID:11353141

Altmann, L; Mundy, W R; Ward, T R; Fastabend, A; Lilienthal, H

2001-06-01

36

Occipital bending in depression.  

PubMed

There are reports of differences in occipital lobe asymmetry within psychiatric populations when compared with healthy control subjects. Anecdotal evidence and enlarged lateral ventricles suggests that there may also be a different pattern of curvature whereby one occipital lobe wraps around the other, termed 'occipital bending'. We investigated the prevalence of occipital bending in 51 patients with major depressive disorder (males mean age = 41.96 ± 14.00 years, females mean age = 40.71 ± 12.41 years) and 48 age- and sex-matched healthy control subjects (males mean age = 40.29 ± 10.23 years, females mean age = 42.47 ± 14.25 years) and found the prevalence to be three times higher among patients with major depressive disorder (18/51, 35.3%) when compared with control subjects (6/48, 12.5%). The results suggest that occipital bending is more common among patients with major depressive disorder than healthy subjects, and that occipital asymmetry and occipital bending are separate phenomena. Incomplete neural pruning may lead to the cranial space available for brain growth being restricted, or ventricular enlargement may exacerbate the natural occipital curvature patterns, subsequently causing the brain to become squashed and forced to 'wrap' around the other occipital lobe. Although the clinical implications of these results are unclear, they provide an impetus for further research into the relevance of occipital bending in major depression disorder. PMID:24740986

Maller, Jerome J; Thomson, Richard H S; Rosenfeld, Jeffrey V; Anderson, Rodney; Daskalakis, Zafiris J; Fitzgerald, Paul B

2014-06-01

37

LocTree3 prediction of localization  

PubMed Central

The prediction of protein sub-cellular localization is an important step toward elucidating protein function. For each query protein sequence, LocTree2 applies machine learning (profile kernel SVM) to predict the native sub-cellular localization in 18 classes for eukaryotes, in six for bacteria and in three for archaea. The method outputs a score that reflects the reliability of each prediction. LocTree2 has performed on par with or better than any other state-of-the-art method. Here, we report the availability of LocTree3 as a public web server. The server includes the machine learning-based LocTree2 and improves over it through the addition of homology-based inference. Assessed on sequence-unique data, LocTree3 reached an 18-state accuracy Q18 = 80 ± 3% for eukaryotes and a six-state accuracy Q6 = 89 ± 4% for bacteria. The server accepts submissions ranging from single protein sequences to entire proteomes. Response time of the unloaded server is about 90 s for a 300-residue eukaryotic protein and a few hours for an entire eukaryotic proteome not considering the generation of the alignments. For over 1000 entirely sequenced organisms, the predictions are directly available as downloads. The web server is available at http://www.rostlab.org/services/loctree3. PMID:24848019

Goldberg, Tatyana; Hecht, Maximilian; Hamp, Tobias; Karl, Timothy; Yachdav, Guy; Ahmed, Nadeem; Altermann, Uwe; Angerer, Philipp; Ansorge, Sonja; Balasz, Kinga; Bernhofer, Michael; Betz, Alexander; Cizmadija, Laura; Do, Kieu Trinh; Gerke, Julia; Greil, Robert; Joerdens, Vadim; Hastreiter, Maximilian; Hembach, Katharina; Herzog, Max; Kalemanov, Maria; Kluge, Michael; Meier, Alice; Nasir, Hassan; Neumaier, Ulrich; Prade, Verena; Reeb, Jonas; Sorokoumov, Aleksandr; Troshani, Ilira; Vorberg, Susann; Waldraff, Sonja; Zierer, Jonas; Nielsen, Henrik; Rost, Burkhard

2014-01-01

38

Downstream targets of methyl CpG binding protein 2 and their abnormal expression in the frontal cortex of the human Rett syndrome brain  

E-print Network

Background: The Rett Syndrome (RTT) brain displays regional histopathology and volumetric reduction, with frontal cortex showing such abnormalities, whereas the occipital cortex is relatively less affected. Results: Using ...

Gibson, Joanne H

39

Maps, Plasticity and Tracts in Visual Cortex Brian Wandell  

E-print Network

field maps and clusters · Cortical plasticity · Reading development (DTI-FT) #12;2 Primary visual cortex Coherence = 0.25 3° Visual field maps and stimulus selectivity in human ventral occipital cortex. A

Wandell, Brian A.

40

Occipital condyle syndrome: self diagnosed  

PubMed Central

We present the case of a 71-year-old man who presented to us with unilateral lower motor neuron hypoglossal palsy along with the characteristic occipital headache. He himself forwarded a paper on occipital condyle syndrome to the clinician who initially reviewed him. Later the patient underwent a series of investigations that confirmed the diagnosis of underlying prostatic carcinoma with widespread metastasis to bones including the base of the skull. Seven months after the diagnosis he is doing well, his headache is much better and the tongue deviation is stable. He was initially treated with tapering doses of dexamethasone and is currently receiving the depo gonadorelin analogue leuprorelin. PMID:21686711

Saraswat, Manoj Kumar; Perera, Ranjit W; Renwick, Ian; Zuromskis, Tadas; Singh, Vijay; Jones, Edward

2009-01-01

41

Lambda waves and occipital generators.  

PubMed

The objective of this study was to identify the relationship between lambda waves (LWs) and other occipital waveforms, in a retrospective analysis of electroencephalograms (EEGs) of clinic and hospitalized patients at a single center. The LWs were correlated with ? rhythm, photic driving, and positive occipital sharp transients of sleep (POSTS). A computer-generated cursor quantified amplitude and duration of POSTS and LWs (3 waveforms and both hemispheres). Fisher exact test was used for significance (P ? .05). A total of 116 patients were evaluated. Of 111 patients, with interpretable results, 74 (66.67%) had visual scanning during EEG, with 37 (50.0%) having LWs. The LWs (17.69 µV) were consistently smaller than POSTS (31.40 µV) despite similar morphology. Patients with an ? rhythm of >8.5 Hz were strongly correlated with the presence of LWs (P < .0001), and those with LWs were strongly predictive of normal EEG (P = .001). Of the 37 patients, 27 (73.0%) with LWs had photic driving (P = .0496). No correlation was found between LWs and POSTS (P = .45). The presence of LWs and a low normal posterior dominant rhythm (PDR) suggests intact electrocerebral health. LWs and the photic driving response suggest similar generators but stimulus-specific networks. POSTS differ from LWs despite similar morphology, suggesting different network activation of occipital generators. LWs have clinical significance in excluding encephalopathy. Occipital generators are differentiated by state and stimulus-dependent network activation and not by location and morphology. PMID:23545245

Tatum, William O; Ly, Reynold C; Sluzewska-Niedzwiedz, Monika; Shih, Jerry J

2013-10-01

42

Functional Plasticity in Ventral Temporal Cortex following Cognitive Rehabilitation of a  

E-print Network

in which face identification abilities are not properly developed in the absence of brain injury or visual occipital temporal face-selective regions (right occipital face area and right fusiform face area occipital temporal cortex. There are two well-studied markers of face pro- cessing: One is the selective

43

Locating the functional and anatomical boundaries of human primary visual cortex Oliver Hindsa,  

E-print Network

. Functional V1 location was measured by parcellating occipital cortex of 10 living humans into visual cortical is tied to the development of the cortical folds. 1. Introduction The primary visual cortex (V1, Brodmann

Schwartz, Eric L.

44

Occipital ossification of balaenopteroid mysticetes.  

PubMed

The bones of the posterior portion of the mammalian skull often exhibit incomplete ossification of the joints between the bones at the time of birth, with complete ossification at some point after birth. The sequence of ossification of these joints in mysticetes can be used to characterize the relative age in the calf and early juvenile ontogenetic stages. This study examined occipital joints ossification of 38 dry prepared neonate specimens in four mysticete species from two families (Eschrichtiidae: Eschrichtius robustus; Balaenopteridae: Balaenoptera acutorostrata, Balaenoptera physalus, and Megaptera novaeangliae). Each of the joints responsible for the fusion of the occiput were examined and rated for degree of ossification. The cranial ossification analysis indicates that E. robustus calves have open occipital joints until ~6 months of age and are born at a less mature stage than closely related balaenopterids. All of the species followed the same sequence of ossification: basioccipital/exoccipital joint, followed by the basioccipital/basisphenoid joint, and completed by the supraoccipital/exoccipital joint. PMID:21290612

Walsh, Breda M; Berta, Annalisa

2011-03-01

45

Visual areas and spatial summation in human visual cortex  

Microsoft Academic Search

Functional MRI measurements can securely partition the human posterior occipital lobe into retinotopically organized visual areas (V1, V2 and V3) with experiments that last only 30 min. Methods for identifying functional areas in the dorsal and ventral aspect of the human occipital cortex, however, have not achieved this level of precision; in fact, different laboratories have produced inconsistent reports concerning

Alyssa A. Brewer; Robert F. Dougherty; Alex R. Wade; Brian A. Wandell

2001-01-01

46

Occipital cortical thickness predicts performance on pitch and musical tasks in blind individuals.  

PubMed

The behavioral and neurofunctional consequences of blindness often include performance enhancements and recruitment of occipital regions for nonvisual tasks. How the neuroanatomical changes resulting from this sensory loss relate to these functional changes is, however, less clear. Previous studies using cortical thickness (CT) measures have shown thicker occipital cortex in early-blind (EB) individuals compared with sighted controls. We hypothesized that this finding reflects the crossmodal plasticity often observed in blind individuals and thus could reflect behavioral adaptations. To address this issue, CT measures in blind (early and late) and sighted subjects were obtained along with several auditory behavioral measures in an attempt to relate behavioral and neuroanatomical changes. Group contrasts confirmed previous results in showing thicker occipital cortex in the EB. Regression analyses between CT measures across the whole brain of all blind individuals with the behavioral scores from 2 tasks in which EB subjects were superior (pitch and melody discrimination) showed that CT of occipital areas was directly related to behavioral enhancements. These findings constitute a compelling demonstration that anatomical changes in occipital areas are directly related to heightened behavioral abilities in the blind and hence support the idea that these anatomical features reflect adaptive compensatory plasticity. PMID:22095215

Voss, Patrice; Zatorre, Robert J

2012-11-01

47

www.rsc.org/loc ISSN 1473-0197  

E-print Network

to the synthesis of monodisperse nanoscale liposomes using 3D microfluidic hydrodynamic focusing in a concentric.rsc.org/loc A facile route to the synthesis of monodisperse nanoscale liposomes using 3D microfluidic hydrodynamic-step continuous flow assembly of monodisperse nanoscale liposomes using three-dimensional microfluidic

Rubloff, Gary W.

48

Childhood Epilepsy With Occipital Paroxysms and Benign Nocturnal Childhood Occipital Epilepsy  

Microsoft Academic Search

Two types of childhood epilepsy have recently been reported: childhood epilepsy with occipital paroxysms, and benign nocturnal childhood occipital epilepsy. This article reports the clinical evolution, electroencephalographic (EEG) changes, and response to therapy of eight children with childhood epilepsy with occipital paroxysms (five boys and three girls, aged from 11\\/12 to 8 years) and eight children with benign nocturnal childhood

Alberto Verrotti; Sergio Domizio; Maria Guerra; Giuseppe Sabatino; Guido Morgese; Francesco Chiarelli

2000-01-01

49

iLoc-Animal: a multi-label learning classifier for predicting subcellular localization of animal proteins.  

PubMed

Predicting protein subcellular localization is a challenging problem, particularly when query proteins have multi-label features meaning that they may simultaneously exist at, or move between, two or more different subcellular location sites. Most of the existing methods can only be used to deal with the single-label proteins. Actually, multi-label proteins should not be ignored because they usually bear some special function worthy of in-depth studies. By introducing the "multi-label learning" approach, a new predictor, called iLoc-Animal, has been developed that can be used to deal with the systems containing both single- and multi-label animal (metazoan except human) proteins. Meanwhile, to measure the prediction quality of a multi-label system in a rigorous way, five indices were introduced; they are "Absolute-True", "Absolute-False" (or Hamming-Loss"), "Accuracy", "Precision", and "Recall". As a demonstration, the jackknife cross-validation was performed with iLoc-Animal on a benchmark dataset of animal proteins classified into the following 20 location sites: (1) acrosome, (2) cell membrane, (3) centriole, (4) centrosome, (5) cell cortex, (6) cytoplasm, (7) cytoskeleton, (8) endoplasmic reticulum, (9) endosome, (10) extracellular, (11) Golgi apparatus, (12) lysosome, (13) mitochondrion, (14) melanosome, (15) microsome, (16) nucleus, (17) peroxisome, (18) plasma membrane, (19) spindle, and (20) synapse, where many proteins belong to two or more locations. For such a complicated system, the outcomes achieved by iLoc-Animal for all the aforementioned five indices were quite encouraging, indicating that the predictor may become a useful tool in this area. It has not escaped our notice that the multi-label approach and the rigorous measurement metrics can also be used to investigate many other multi-label problems in molecular biology. As a user-friendly web-server, iLoc-Animal is freely accessible to the public at the web-site . PMID:23370050

Lin, Wei-Zhong; Fang, Jian-An; Xiao, Xuan; Chou, Kuo-Chen

2013-04-01

50

The anatomy of fronto-occipital connections from early blunt dissections to contemporary tractography.  

PubMed

The occipital and frontal lobes are anatomically distant yet functionally highly integrated to generate some of the most complex behaviour. A series of long associative fibres, such as the fronto-occipital networks, mediate this integration via rapid feed-forward propagation of visual input to anterior frontal regions and direct top-down modulation of early visual processing. Despite the vast number of anatomical investigations a general consensus on the anatomy of fronto-occipital connections is not forthcoming. For example, in the monkey the existence of a human equivalent of the 'inferior fronto-occipital fasciculus' (iFOF) has not been demonstrated. Conversely, a 'superior fronto-occipital fasciculus' (sFOF), also referred to as 'subcallosal bundle' by some authors, is reported in monkey axonal tracing studies but not in human dissections. In this study our aim is twofold. First, we use diffusion tractography to delineate the in vivo anatomy of the sFOF and the iFOF in 30 healthy subjects and three acallosal brains. Second, we provide a comprehensive review of the post-mortem and neuroimaging studies of the fronto-occipital connections published over the last two centuries, together with the first integral translation of Onufrowicz's original description of a human fronto-occipital fasciculus (1887) and Muratoff's report of the 'subcallosal bundle' in animals (1893). Our tractography dissections suggest that in the human brain (i) the iFOF is a bilateral association pathway connecting ventro-medial occipital cortex to orbital and polar frontal cortex, (ii) the sFOF overlaps with branches of the superior longitudinal fasciculus (SLF) and probably represents an 'occipital extension' of the SLF, (iii) the subcallosal bundle of Muratoff is probably a complex tract encompassing ascending thalamo-frontal and descending fronto-caudate connections and is therefore a projection rather than an associative tract. In conclusion, our experimental findings and review of the literature suggest that a ventral pathway in humans, namely the iFOF, mediates a direct communication between occipital and frontal lobes. Whether the iFOF represents a unique human pathway awaits further ad hoc investigations in animals. PMID:23137651

Forkel, Stephanie J; Thiebaut de Schotten, Michel; Kawadler, Jamie M; Dell'Acqua, Flavio; Danek, Adrian; Catani, Marco

2014-07-01

51

Adverse effect profile of Lidocaine injections for occipital nerve block in occipital neuralgia  

Microsoft Academic Search

To determine whether there are differences in the adverse effect profile between 1, 2 and 5% Lidocaine when used for occipital\\u000a nerve blocks (ONB) in patients with occipital neuralgia. Occipital neuralgia is an uncommon cause of headaches. Little is\\u000a known regarding the safety of Lidocaine injections for treatment in larger series of patients. Retrospective chart analysis\\u000a of all ONB was

Soma Sahai-SrivastavaDawood Subhani; Dawood Subhani

2010-01-01

52

Occipital Nerve Stimulation for Refractory Occipital Pain after Occipitocervical Fusion: Expanding Indications  

Microsoft Academic Search

Background: Occipital nerve stimulation is being used for various pain syndromes. Here, we expand its use for the treatment of refractory occipital pain after occipitocervical fusion. Case Description: We describe a case of occipital neuralgia in a 60-year-old man following posterior occipitocervical fusion. The maximum pain intensity was rated 9\\/10 on the visual analogue scale (VAS). Since pain proved to

Kazem Ghaemi; Hans-Holger Capelle; Thomas M. Kinfe; Joachim K. Krauss

2008-01-01

53

Social appraisal in chronic psychosis: Role of medial frontal and occipital networks  

PubMed Central

Persons with schizophrenia often appraise other individuals as threatening or persecutory. To evaluate social appraisal in schizophrenia, we probed brain networks with a task in which subjects judged whether or not they liked face stimuli with emotional expressions. We predicted that appraising negative expressions would engage patients, more than controls, and negative faces would be related to higher levels of negative affect and produce increased activity in the medial frontal cortex, an area involved in social appraisal. Twenty-one stable outpatients with chronic non-affective psychosis (16 schizophrenic, 5 schizoaffective) and 21 healthy subjects underwent functional magnetic resonance imaging. Compared with the control subjects, patients were slower to respond, but particularly slow when they judged negatively-valenced faces, a slowness correlated with negative affect in the psychosis patients. Appraisal activated the medial prefrontal cortex (mPFC) across all face valences. For negative expressions, patients exhibited greater activation of the dorsal anterior cingulate cortex (dACC). A psychophysiological interaction analysis of the dACC revealed co-modulation of the mPFC in controls, significantly less in patients, and a trend for co-modulation of occipital cortex in the patients. Activity in occipital cortex correlated with poor social adjustment and impaired social cognition, and co-modulation of the occipital gyrus by the dACC was correlated with poorer social cognition. The findings link appraisal of negative affect with aberrant activation of the medial frontal cortex, while early sensory processing of this social cognitive task was linked with poor social function, reflecting either top down or bottom up influences. PMID:20797730

Taylor, Stephan F.; Chen, Ashley C.; Tso, Ivy F.; Liberzon, Israel; Welsh, Robert C.

2010-01-01

54

The role of the occipital face area in the cortical face perception network  

Microsoft Academic Search

Functional magnetic resonance imaging (fMRI) studies have identified spatially distinct face-selective regions in human cortex.\\u000a These regions have been linked together to form the components of a cortical network specialized for face perception but the\\u000a cognitive operations performed in each region are not well understood. In this paper, we review the evidence concerning one\\u000a of these face-selective regions, the occipital

David Pitcher; Vincent Walsh; Bradley Duchaine

2011-01-01

55

Development of the micro-architecture and mineralization of the basilar part of the pig occipital bone  

Microsoft Academic Search

In this study, the development of the architecture and the degree and distribution of mineralization in the basilar part of the pig occipital bone, one of the contact points between the spine and skull base, was investigated. Multiple regions of the basiocciput of pig specimens of different gestational ages were examined with three-dimensional microcomputed tomography (microCT). The cortex of the

Ruud J. A. Sips; Lars Mulder; Jan Harm Koolstra; Eijden van T. M. G. J

2008-01-01

56

The Sunrise Technique: The Correction of Occipital Plagiocephaly Using Bandeau Occipital Plate and Radial Osteotomies  

Microsoft Academic Search

Posterior plagiocephaly secondary to lambdoid suture stenosis requires surgical release and repair to prevent progressive deformational changes associated with a suture stenosis. A surgical technique is described for release of the stenosed lambdoid suture and asterion region, followed by occipital reconstruction. This technique provides excellent cosmetic results. Using a standard biparietal incision, most of the occipital bone is removed en

David F. Jimenez; Constance M. Barone

1995-01-01

57

Does shape discrimination by the mouth activate the parietal and occipital lobes? - near-infrared spectroscopy study.  

PubMed

A cross-modal association between somatosensory tactile sensation and parietal and occipital activities during Braille reading was initially discovered in tests with blind subjects, with sighted and blindfolded healthy subjects used as controls. However, the neural background of oral stereognosis remains unclear. In the present study, we investigated whether the parietal and occipital cortices are activated during shape discrimination by the mouth using functional near-infrared spectroscopy (fNIRS). Following presentation of the test piece shape, a sham discrimination trial without the test pieces induced posterior parietal lobe (BA7), extrastriate cortex (BA18, BA19), and striate cortex (BA17) activation as compared with the rest session, while shape discrimination of the test pieces markedly activated those areas as compared with the rest session. Furthermore, shape discrimination of the test pieces specifically activated the posterior parietal cortex (precuneus/BA7), extrastriate cortex (BA18, 19), and striate cortex (BA17), as compared with sham sessions without a test piece. We concluded that oral tactile sensation is recognized through tactile/visual cross-modal substrates in the parietal and occipital cortices during shape discrimination by the mouth. PMID:25299397

Kagawa, Tomonori; Narita, Noriyuki; Iwaki, Sunao; Kawasaki, Shingo; Kamiya, Kazunobu; Minakuchi, Shunsuke

2014-01-01

58

Does Shape Discrimination by the Mouth Activate the Parietal and Occipital Lobes? - Near-Infrared Spectroscopy Study  

PubMed Central

A cross-modal association between somatosensory tactile sensation and parietal and occipital activities during Braille reading was initially discovered in tests with blind subjects, with sighted and blindfolded healthy subjects used as controls. However, the neural background of oral stereognosis remains unclear. In the present study, we investigated whether the parietal and occipital cortices are activated during shape discrimination by the mouth using functional near-infrared spectroscopy (fNIRS). Following presentation of the test piece shape, a sham discrimination trial without the test pieces induced posterior parietal lobe (BA7), extrastriate cortex (BA18, BA19), and striate cortex (BA17) activation as compared with the rest session, while shape discrimination of the test pieces markedly activated those areas as compared with the rest session. Furthermore, shape discrimination of the test pieces specifically activated the posterior parietal cortex (precuneus/BA7), extrastriate cortex (BA18, 19), and striate cortex (BA17), as compared with sham sessions without a test piece. We concluded that oral tactile sensation is recognized through tactile/visual cross-modal substrates in the parietal and occipital cortices during shape discrimination by the mouth. PMID:25299397

Kagawa, Tomonori; Narita, Noriyuki; Iwaki, Sunao; Kawasaki, Shingo; Kamiya, Kazunobu; Minakuchi, Shunsuke

2014-01-01

59

Hypoplastic occipital condyle and third occipital condyle: review of their dysembryology.  

PubMed

Disruption or embryologic derailment of the normal bony architecture of the craniovertebral junction (CVJ) may result in symptoms. As studies of the embryology and pathology of hypoplasia of the occipital condyles and third occipital condyles are lacking in the literature, the present review was performed. Standard search engines were accessed and queried for publications regarding hypoplastic occipital condyles and third occipital condyles. The literature supports the notion that occipital condyle hypoplasia and a third occipital condyle are due to malformation or persistence of the proatlas, respectively. The Pax-1 gene is most likely involved in this process. Clinically, condylar hypoplasia may narrow the foramen magnum and lead to lateral medullary compression. Additionally, this maldevelopment can result in transient vertebral artery compression secondary to posterior subluxation of the occiput. Third occipital condyles have been associated with cervical canal stenosis, hypoplasia of the dens, transverse ligament laxity, and atlanto-axial instability causing acute and chronic spinal cord compression. Treatment goals are focused on craniovertebral stability. A better understanding of the embryology and pathology related to CVJ anomalies is useful to the clinician treating patients presenting with these entities. PMID:23338989

Tubbs, R Shane; Lingo, Patrick Ryan; Mortazavi, Martin M; Cohen-Gadol, Aaron A

2013-11-01

60

Localizing Retinotopic fMRI Activation in Human Primary Visual Cortex via Dynamic Programming  

E-print Network

representation in the visual cortex moves anteriorly from the occipital pole. Furthermore, the polar angle possibilities for the study of pathologic vision and inform the development of new strategies for rehabilitation/white matter boundary of the occipital lobe. The ridge of maximum activation on the surface due to each ring

Qiu, Anqi

61

Population receptive field estimates in human visual cortex Serge O. Dumoulin and Brian A. Wandell  

E-print Network

and ventral occipital regions of human visual cortex. Also, we quantify the amount of input from ipsi neurons measured at the micron scale. The new methods build on techniques that were developed for visual

Wandell, Brian A.

62

Occipital Alpha Training in Mentally Retarded Adolescents.  

ERIC Educational Resources Information Center

Retarded Ss receiving occipital alpha feedback significantly decreased their alpha density in reference to the random feedback (control) group. Results are discussed in terms of potential implications for visual attention, training techniques for mentally retarded adolescents, and other biofeedback applications. (Author)

Thorson, Gary; Lipscomb, Thomas

1982-01-01

63

Autism and visual agnosia in a child with right occipital lobectomy  

PubMed Central

OBJECTIVES—Autistic disorder is a developmental handicap with an unknown neurological basis. Current neuropsychological models for autism suggest an abnormal construction of visual perceptual representation or a deficit in executive functions. These models predict cerebral lesions in the temporo-occipital or frontal regions of autistic patients. The present study aimed at studying the presence of symptoms of autism and visual agnosia in a 13 year old girl who had a right temporo-occipital cortical dysplasia that was surgically removed at the age of 7.?METHODS—Neuropsychological evaluation included Wechsler and Kaufman intelligence scales, a test of word fluency, digit span, Corsi block, California verbal learning, Trail making, Benton facial recognition, Snoodgrass object recognition tests, Rivermead face learning subtest, and developmental test of visual perception. The ADI-R was used to show current and retrospective diagnosis of autistic disorder. Neuroimagery included brain MRI, single photon emission computed tomography (SPECT), and PET.?RESULTS—Brain MRI showed a right occipital defect and an abnormal hyperintensity of the right temporal cortex. PET and SPECT disclosed a left frontal hypometabolism together with the right occipital defect. Neuropsychological testing showed a visual apperceptive agnosia and executive function deficits. Psychiatric study confirmed the diagnosis of autistic disorder.?CONCLUSIONS—Although the possibilty that autism and visual agnosia were dissociable factors in this patient cannot be excluded, the finding of both deficits supports the possibility that occipito-temporal lesions can predispose to the development of autism.?? PMID:9771784

Jambaque, I; Mottron, L; Ponsot, G; Chiron, C

1998-01-01

64

Occipital cortical proton MRS at 4 Tesla in human moderate MDMA polydrug users  

PubMed Central

The recreational drug MDMA (3,4, methylenedioxymethamphetamine; sold under the street name of Ecstasy) is toxic to serotonergic axons in some animal models of MDMA administration. In humans, MDMA use is associated with alterations in markers of brain function that are pronounced in occipital cortex. Among neuroimaging methods, magnetic resonance spectroscopy (MRS) studies of brain metabolites N-acetylaspartate (NAA) and myoinositol (MI) at a field strength of 1.5 Tesla (T) reveal inconsistent results in MDMA users. Because higher field strength proton MRS has theoretical advantages over lower field strengths, we used proton MRS at 4.0 T to study absolute concentrations of occipital cortical NAA and MI in a cohort of moderate MDMA users (n = 9) versus non-MDMA using (n = 7) controls. Mean NAA in non-MDMA users was 10.47 mM (± 2.51), versus 9.83 mM (± 1.94) in MDMA users. Mean MI in non-MDMA users was 7.43 mM (± 1.68), versus 6.57 mM (± 1.59) in MDMA users. There were no statistical differences in absolute metabolite levels for NAA and MI in occipital cortex of MDMA users and controls. These findings are not supportive of MDMA-induced alterations in NAA or MI levels in this small sample of moderate MDMA users. Limitations to this study suggest caution in the interpretation of these results. PMID:17574394

Cowan, Ronald L.; Bolo, Nicolas R.; Dietrich, Mary; Haga, Erica; Lukas, Scott E.; Renshaw, Perry F.

2007-01-01

65

Retrieval Success is Accompanied by Enhanced Activation in Anterior Prefrontal Cortex During Recognition Memory: An Event-Related fMRI Study  

Microsoft Academic Search

Neural regions associated with retrieval success were identified using event-related fMRI procedures and randomly ordered trials on a recognition memory test. Differences between hits and correct rejections (CRs) occurred in multiple regions, including bilateral anterior and right dorsolateral prefrontal cortex, bilateral inferior parietal cortex, and right superior parietal cortex (all hits > CRs), and right occipital cortex (CRs > hits).

Kathleen B. McDermott; Todd C. Jones; Steven E. Petersen; Sarah K. Lageman; Henry L. Roediger

2000-01-01

66

The stress at the human atlanto-occipital joint  

Microsoft Academic Search

The development of the occipital condyle has been observed in human fetuses, neonates, children, and juveniles. In contrast to some authorities, the authors believe the occipital condyle to originate from the basioccipital and the exoccipital of the occipital bone. The bony parts of the condyle are divided by the synchondrosis intraoccipitalis anterior. The rostral area on the basioccipital occupies about

Bernhard Tillmann; René Lorenz

1978-01-01

67

Occipital-Callosal Pathways in Children: Validation and Atlas Development  

Microsoft Academic Search

Diffusion tensor imaging and fiber tracking were used to measure fiber bundles connecting the two occipital lobes in 53 children of 7-12 years of age. Independent fiber bundle estimates originating from the two hemispheres converge onto the lower half of the splenium. This observation validates the basic methodology and suggests that most occipital-callosal fibers connect the two occipital lobes. Within

ROBERT F. DOUGHERTY; MICHAL BEN-SHACHAR; GAYLE DEUTSCH; POLINA POTANINA; ROLAND BAMMER; BRIAN A. WANDELLa

2005-01-01

68

Presumed bilateral occipital neurosarcoidosis. A case report.  

PubMed

A 37-year-old man with a history of sarcoidosis, hypertension, asthma, depression and prior intravenous drug use presented with complaints of difficulty in finding his way around the house, headache, and blurred vision in both eyes. The symptoms had been increasing in severity over the prior several months. Physical examination showed normal visual acuity, pupil reactions, and fundi but severe, circumferential constriction of the visual fields bilaterally. The visual fields enlarged appropriately on increasing the distance from the patient to the tangent screen. Neuroimaging revealed bilateral, occipital meningeal involvement and parenchymal lesions consistent with sarcoidosis. Treatment with oral corticosteroids produced a mild subjective improvement in the patient's symptoms and stabilized the visual fields, without improving them. This case represents an unusual presentation of presumed neurosarcoidosis involving the visual pathways at the level of the occipital lobes. PMID:9532537

Givre, S J; Mindel, J S

1998-03-01

69

Meningocele following aplasia of the occipital bone  

Microsoft Academic Search

We describe a first trimester female foetus with aplasia of the occipital bone allowing a meningocele without skin coverage to be formed. The pregnancy was terminated, and on later autopsy the brain appeared to be intact. The foetus carried an apparently balanced translocation 46,XX,t(3;9)(p21.3;q22.3) inherited from a normal father and grandfather.

Torbjørn M Eggebø; Janne Brathetland; Hege U Dirdal; Gunnar Houge

2011-01-01

70

PlantLoc: an accurate web server for predicting plant protein subcellular localization by substantiality motif  

PubMed Central

Knowledge of subcellular localizations (SCLs) of plant proteins relates to their functions and aids in understanding the regulation of biological processes at the cellular level. We present PlantLoc, a highly accurate and fast webserver for predicting the multi-label SCLs of plant proteins. The PlantLoc server has two innovative characters: building localization motif libraries by a recursive method without alignment and Gene Ontology information; and establishing simple architecture for rapidly and accurately identifying plant protein SCLs without a machine learning algorithm. PlantLoc provides predicted SCLs results, confidence estimates and which is the substantiality motif and where it is located on the sequence. PlantLoc achieved the highest accuracy (overall accuracy of 80.8%) of identification of plant protein SCLs as benchmarked by using a new test dataset compared other plant SCL prediction webservers. The ability of PlantLoc to predict multiple sites was also significantly higher than for any other webserver. The predicted substantiality motifs of queries also have great potential for analysis of relationships with protein functional regions. The PlantLoc server is available at http://cal.tongji.edu.cn/PlantLoc/. PMID:23729470

Tang, Shengnan; Li, Tonghua; Cong, Peisheng; Xiong, Wenwei; Wang, Zhiheng; Sun, Jiangming

2013-01-01

71

Amount of lifetime video gaming is positively associated with entorhinal, hippocampal and occipital volume.  

PubMed

Playing video games is a popular leisure activity among children and adults, and may therefore potentially influence brain structure. We have previously shown a positive association between probability of gray matter (GM) volume in the ventral striatum and frequent video gaming in adolescence. Here we set out to investigate structural correlates of video gaming in adulthood, as the effects observed in adolescents may reflect only a fraction of the potential neural long-term effects seen in adults. On magnetic resonance imaging (MRI) scans of 62 male adults, we computed voxel-based morphometry to explore the correlation of GM with the lifetime amount of video gaming (termed joystick years). We found a significant positive association between GM in bilateral parahippocamal region (entorhinal cortex) and left occipital cortex/inferior parietal lobe and joystick years (P<0.001, corrected for multiple comparisons). An exploratory analysis showed that the entorhinal GM volume can be predicted by the video game genres played, such as logic/puzzle games and platform games contributing positively, and action-based role-playing games contributing negatively. Furthermore, joystick years were positively correlated with hippocampus volume. The association of lifetime amount of video game playing with bilateral entorhinal cortex, hippocampal and occipital GM volume could reflect adaptive neural plasticity related to navigation and visual attention. PMID:23958958

Kühn, S; Gallinat, J

2014-07-01

72

Visual sensory-motor gating by serotonin activation in the medial prefrontal and occipital, but not in the rhinal, cortices in rats  

Microsoft Academic Search

A behavioral reaction to sensory stimulation is a basic mechanism which is pivotal to many complex behavioral responses. In previous studies we found that visual stimulation induces a selective serotonergic and dopaminergic activation in the occipital (OccC), but not temporal (TempC) cortex in freely moving rats. In a behavioral study in rats we demonstrate now that visual stimulation (0, 8,

M. E. Pum; J. P. Huston; M. A. De Souza Silva; C. P. Müller

2008-01-01

73

Motor activity and imagery modulate the body-selective region in the occipital–temporal area: A near-infrared spectroscopy study  

Microsoft Academic Search

The extrastriate body area (EBA) lies in the occipital–temporal cortex and has been described as a “body-selective” region that responds when viewing other people's bodies. Recently, several studies have reported that EBA is also modulated when the subject moves or imagines moving their own body, even without visual feedback. The present study involved 3 experiments, wherein the first experiment was

Tomohiro Ishizu; Asuka Noguchi; Yoshie Ito; Tomoaki Ayabe; Shozo Kojima

2009-01-01

74

Attenuating illusory binding with TMS of the right parietal cortex Michael Esterman,a,b, Timothy Verstynen,a  

E-print Network

at the junction of the transverse occipital sulcus (IPS/TOS). These results support a role for the parietal cortex combinations of letters and colors. This contributed to the development of feature integration theory (FIT

Robertson, Lynn

75

FOCUS www.rsc.org/loc | Lab on a Chip Improving fluorescence detection in lab on  

E-print Network

) graft on glass. Two cell populations are separately labeled with live cell dyes and are mixed and seeded, and entanglement.18­20 Present state of the art LOC devices are typically fabricated out of glass or PDMS

Fygenson, Deborah Kuchnir

76

LocALE: A Location-Aware Lifecycle Environment for Ubiquitous Computing  

Microsoft Academic Search

The LocALE (Location-Aware Lifecycle Environment) framework provides a simple management interface for controlling the lifecycle of CORBA distributed objects. It supports mechanisms for the remote construction, movement, removal and recovery of heterogeneous software objects in a location domain, i.e. a group of hosts on a network within a given physical area. Client applications use LocALE to intelligently control their required

Diego López De Ipiña; Sai-Lai Lo

2001-01-01

77

Subdivision of the occipital lobes: an anatomical and functional MRI connectivity study.  

PubMed

Exploring brain connectivity is fundamental to understanding the functional architecture of the cortex. In our study we employed tractography-based parcellation, combined with the principal component analysis statistical framework, to divide the occipital lobes into seven areas in a group of eighteen healthy participants. Tractography-based parcellation is a method based on diffusion imaging tractography, which segregates the living human brain into distinctive areas showing sharp differences in their anatomical connectivity. The results were compared to covarying functional networks involving distinct areas within the occipital lobes, that we obtained using resting state functional magnetic resonance imaging (fMRI), as well as to other existing subdivisions of the occipital lobes. Our results showed similarities with functional imaging data in healthy controls and cognitive profiles in brain-damaged patients, although several differences with cytoarchitectonic, myelogenetic, myeloarchitectonic and functional maps were reported. While the similarities are encouraging, the potential validity and limitations of the differences observed are discussed. Taken together these results suggest that tractography-based parcellation may provide a new promising anatomical subdivision of the living human brain based on its anatomical connectivity, which may benefit the understanding of clinical-neuroanatomical dissociations and functional neuroimaging results. PMID:23312799

Thiebaut de Schotten, Michel; Urbanski, Marika; Valabregue, Romain; Bayle, Dimitri J; Volle, Emmanuelle

2014-07-01

78

Persistent Aura with Small Occipital Cortical Infarction: Implications for Migraine Pathophysiology  

PubMed Central

Objective The pathophysiology of migraine with aura is thought to be related to cortical spreading depression and cortical hypersensitivity, in which inhibitory interneurons may play a role. Persistent migraine aura (PMA) without infarction is defined as auras that last longer than 1 week in the absence of infarction. We describe a case of persistent aura with a small occipital cortical infarction and discuss implications of this case and PMA for pathophysiological concepts of migrainous auras. Methods We present a case and discuss the implications for pathophysiological concepts. Results The case presented cannot be diagnosed as PMA as the patient was found to have an occipital cortical infarction with hypoactivity on fluorodeoxyglucose-positron emission tomography. Nevertheless, the patient suffered from persistent aura (with infarction). We argue that the infarction may have been responsible for an increased imbalance in one of the primary visual cortex networks that was already hyperexcitable due to the migraine aura condition. Conclusion PMA with occipital infarction has not been reported previously. We believe the findings of the present case and PMA cases reported in the past may support the intracortical disinhibition hypothesis in migraine.

Thissen, Sam; Koehler, Peter J.

2014-01-01

79

The occipital torus and developmental age of Sangiran-3  

Microsoft Academic Search

Since its discovery in 1938 Sangiran-3 has been considered a juvenilePithecanthropus(Homo)erectusand therefore, excluded from studies of adultH. erectusAlthough morphological features align Sangiran-3 withH. erectusits age designation rests on an unconvincing reconstruction of the occipital torus and lack of sutural fusion. Evaluation of the occipital shows the original reconstruction is faulty and that the current midline occipital torus is actually the

Susan C. Antón; Jens Lorenz Franzen

1997-01-01

80

Craniocervical junction trauma with occipital condyle fracture; case report  

Microsoft Academic Search

Authors present the case of a unilateral occipital condyle fracture diagnosed with computed tomography (CT) in a motor vehicle\\u000a accident victim. Patient had unilateral occipital condyle fracture with inferomedially displaced bone fragment, a type 3 fracture\\u000a according to the Anderson and Montesano classification of occipital condyle fractures, bilaterally widened occipitoatlantal\\u000a joint space, and head mowed forward in relation to the

Ivan Žokalj; Hussein Saghir; Jasminka Igrec; Zlatko Pav?ec

2010-01-01

81

Coherent Activity in Bilateral Parieto-Occipital Cortices during P300-BCI Operation  

PubMed Central

The visual P300 brain–computer interface (BCI), a popular system for electroencephalography (EEG)-based BCI, uses the P300 event-related potential to select an icon arranged in a flicker matrix. In earlier studies, we used green/blue (GB) luminance and chromatic changes in the P300-BCI system and reported that this luminance and chromatic flicker matrix was associated with better performance and greater subject comfort compared with the conventional white/gray (WG) luminance flicker matrix. To highlight areas involved in improved P300-BCI performance, we used simultaneous EEG–fMRI recordings and showed enhanced activities in bilateral and right lateralized parieto-occipital areas. Here, to capture coherent activities of the areas during P300-BCI, we collected whole-head 306-channel magnetoencephalography data. When comparing functional connectivity between the right and left parieto-occipital channels, significantly greater functional connectivity in the alpha band was observed under the GB flicker matrix condition than under the WG flicker matrix condition. Current sources were estimated with a narrow-band adaptive spatial filter, and mean imaginary coherence was computed in the alpha band. Significantly greater coherence was observed in the right posterior parietal cortex under the GB than under the WG condition. Re-analysis of previous EEG-based P300-BCI data showed significant correlations between the power of the coherence of the bilateral parieto-occipital cortices and their performance accuracy. These results suggest that coherent activity in the bilateral parieto-occipital cortices plays a significant role in effectively driving the P300-BCI. PMID:24860546

Takano, Kouji; Ora, Hiroki; Sekihara, Kensuke; Iwaki, Sunao; Kansaku, Kenji

2013-01-01

82

TMS to the "occipital face area" affects recognition but not categorization of faces.  

PubMed

The human cortical system for face perception is comprised of a network of connected regions including the middle fusiform gyrus ("fusiform face area" or FFA), the inferior occipital cortex ("occipital face area" or OFA), and the superior temporal sulcus. The traditional hierarchical feedforward model of visual processing suggests information flows from early visual cortex to the OFA for initial face feature analysis to higher order regions including the FFA for identity recognition. However, patient data suggest an alternative model. Patients with acquired prosopagnosia, an inability to visually recognize faces, have been documented with lesions to the OFA but who nevertheless show face-selective activation in the FFA. Moreover, their ability to categorize faces remains intact. This suggests that the FFA is not solely responsible for face recognition and the network is not strictly hierarchical, but may be organized in a reverse hierarchical fashion. We used transcranial magnetic stimulation (TMS) to temporarily disrupt processing in the OFA in neurologically-intact individuals and found participants' ability to categorize intact versus scrambled faces was unaffected, however face identity discrimination was significantly impaired. This suggests that face categorization but not recognition can occur without the "earlier" OFA being online and indicates that "lower level" face category processing may be assumed by other intact face network regions such as the FFA. These results are consistent with the patient data and support a non-hierarchical, global-to-local model with re-entrant connections between the OFA and other face processing areas. PMID:24077427

Solomon-Harris, Lily M; Mullin, Caitlin R; Steeves, Jennifer K E

2013-12-01

83

The learning of perceptual skills is thought to rely upon multiple regions in the cerebral cortex, but imaging studies have not yet  

E-print Network

The learning of perceptual skills is thought to rely upon multiple regions in the cerebral cortex in the cerebral cortex, basal ganglia and cerebellum (reviewed in Poldrack and Gabrieli, 1997). The procedural and practiced stimuli. Multiple regions in the occipital lobe, inferior temporal cortex, superior parietal

Poldrack, Russ

84

Traumatic atlanto-occipital dislocation in children.  

PubMed

Although once considered an invariably fatal injury, improvements in diagnosis and management have made atlanto-occipital dislocation (AOD) a survivable injury. MRI is the preferred imaging modality; occasionally, flexion/extension/distraction fluoroscopy may be required to determine craniovertebral stability. Early surgical stabilization is recommended for all children with AOD. Early occipitocervical fusion using screws in combination with a rod or plate, or sublaminar wires with a contoured rod, coupled with autograft bone, provide immediate stabilization and a high fusion rate. Halo immobilization and traction are contraindicated in the management of AOD in children because of the risk of displacement of the injured occipitocervical joint. Postoperative hydrocephalus is frequent and should be suspected when neurologic decline occurs after fixation. Nearly half of children who survive AOD will have residual neurologic deficits. PMID:24788443

Astur, Nelson; Sawyer, Jeffrey R; Klimo, Paul; Kelly, Derek M; Muhlbauer, Michael; Warner, William C

2014-05-01

85

Greater occipital nerve blockade in cervicogenic headache.  

PubMed

Cervicocogenic headache (CeH) is a relatively common disorder. Although on ideal treatment is available so far, blockades in different structures and nerves may be temporarily effective. We studied the effects of 1-2 mL 0.5% bupivacaine injection at the ipsilateral greater occipital nerve (GON) in 41 CeH patients. The pain is significantly reduced both immediately and as long as 7 days after the blockade. The improvement is less marked during the first two days, a phenomenon we called "tilde pattern". GON blockades may reduce the pool of exaggerated sensory input and antagonize a putative "wind-up-like effect" which may explain the headache improvement. PMID:10029873

Vincent, M B; Luna, R A; Scandiuzzi, D; Novis, S A

1998-12-01

86

Reorganization of Retinotopic Maps after Occipital Lobe Infarction  

E-print Network

U ncorrected Proof Reorganization of Retinotopic Maps after Occipital Lobe Infarction Lucia M , and Alan Cowey3,4* Abstract We studied patient JS, who had a right occipital infarct that encroached used fMRI to perform retinotopic mapping at 3, 8, and 11 months after the infarct. We quantified

Vaina, Lucia M.

87

An Occipital Encephalocystocele Involving Both Sides of the Lateral Ventricles  

Microsoft Academic Search

We reported a rare case of an occipital encephalocystocele linked by bilateral posterior horns of the lateral ventricles. The subject was a newborn girl with a large occipital cephalocele (6 × 9 cm in diameter) covered with alopetic skin. Cerebrospinal fluid leakage was not observed. The fontanel was soft, but a characteristic flat forehead was noted. Neither neurological deficits nor

Kazumichi Yamada; Masaki Miura; Jun Matsumoto; Takako Uchino; Yuichi Kondo; Yukitaka Ushio

2000-01-01

88

Cooled Radiofrequency Ablation for Bilateral Greater Occipital Neuralgia  

PubMed Central

This report describes a case of bilateral greater occipital neuralgia treated with cooled radiofrequency ablation. The case is considered in relation to a review of greater occipital neuralgia, continuous thermal and pulsed radiofrequency ablation, and current medical literature on cooled radiofrequency ablation. In this case, a 35-year-old female with a 2.5-year history of chronic suboccipital bilateral headaches, described as constant, burning, and pulsating pain that started at the suboccipital region and radiated into her vertex. She was diagnosed with bilateral greater occipital neuralgia. She underwent cooled radiofrequency ablation of bilateral greater occipital nerves with minimal side effects and 75% pain reduction. Cooled radiofrequency ablation of the greater occipital nerve in challenging cases is an alternative to pulsed and continuous RFA to alleviate pain with less side effects and potential for long-term efficacy. PMID:24716017

Chhatre, Akhil

2014-01-01

89

Occipital-posterior cerebral artery bypass via the occipital interhemispheric approach  

PubMed Central

Background: The unavailability of the superficial temporal artery (STA) and the location of lesions pose a more technically demanding challenge when compared with conventional STA-superior cerebellar or posterior cerebral artery (PCA) bypass in vascular reconstruction procedures. To describe a case series of patients with cerebrovascular lesions who were treated using an occipital artery (OA) to PCA bypass via the occipital interhemispheric approach. Methods: We retrospectively reviewed three consecutive cases of patients with cerebrovascular lesions who were treated using OA-PCA bypass. Results: OA-PCA bypass was performed via the occipital interhemispheric approach. This procedure included: (1) OA-PCA bypass (n = 1), and combined OA-posterior inferior cerebellar artery and OA-PCA saphenous vein interposition graft bypass (n = 1) in patients with vertebrobasilar ischemia; (2) OA-PCA radial artery interposition graft bypass in one patient with residual PCA aneurysm. Conclusions: OA-PCA bypass represents a useful alternative to conventional STA-SCA or PCA bypass. PMID:23956933

Kazumata, Ken; Yokoyama, Yuka; Sugiyama, Taku; Asaoka, Katsuyuki

2013-01-01

90

Top-Down Feedback in an HMAX-Like Cortical Model of Object Perception Based on Hierarchical Bayesian  

E-print Network

such as invariance to transformations or feedback reconstruction. In this study we develop a Bayesian network-level areas, such as V4, inferotemporal (IT) cortex, lateral occipital complex (LOC) or middle temporal (MT

Wennekers, Thomas

91

The motor hierarchy: from kinematics to goals and intentions  

E-print Network

of the hierarchy have not been easy to localise in the human brain. We have recently developed a one-back paradigm compared to novel grasps was found in the lateral occipital cortex (LOC), middle intraparietal sulcus

Hamilton, Antonia

92

Mirror Focus in a Patient with Intractable Occipital Lobe Epilepsy  

PubMed Central

Mirror focus is one of the evidence of progression in epilepsy, and also has practical points for curative resective epilepsy surgery. The mirror foci are related to the kindling phenomena that occur through interhemispheric callosal or commissural connections. A mirror focus means the secondary epileptogenic foci develop in the contralateral hemispheric homotopic area. Thus mirror foci are mostly reported in patients with temporal or frontal lobe epilepsy, but not in occipital lobe epilepsy. We have observed occipital lobe epilepsy with mirror focus. Before epilepsy surgery, the subject’s seizure onset zone was observed in the left occipital area by ictal studies. Her seizures abated for 10 months after the resection of left occipital epileptogenic focus, but recurred then. The recurred seizures were originated from the right occipital area which was in the homotopic contralateral area. This case can be an evidence that occipital lobe epilepsy may have mirror foci, even though each occipital lobe has any direct interhemispheric callosal connections between them. PMID:24977131

Kim, Jiyoung; Shin, Hae kyung; Hwang, Kyoung Jin; Choi, Su Jung; Joo, Eun Yeon; Hong, Seung Bong; Hong, Seung Chul; Seo, Dae-Won

2014-01-01

93

Neuron, Vol. 37, 10271041, March 27, 2003, Copyright 2003 by Cell Press Large-Scale Mirror-Symmetry Organization  

E-print Network

, was originally termed the lateral occipitalIsrael complex (LOC; Malach et al., 1995). More recently, this cortex was subdivided into a more dorsal region (lateral- occipital region [LO]) and a more ventral region (the to a possible development of high-order of the human object cortex grows, so will the numberobject areas through

Hasson, Uri

94

Expression of Cellular Prion Protein in the Frontal and Occipital Lobe in Alzheimer's Disease, Diffuse Lewy Body Disease, and in Normal Brain: An Immunohistochemical Study  

Microsoft Academic Search

Cellular prion protein (PrPc) is a glycoprotein expressed at low to moderate levels within the nervous system. Recent studies suggest that PrPc may possess neuroprotective functions and that its expression is upregulated in certain neurodegenerative disorders. We investigated whether PrPc expression is altered in the frontal and occipital cortex in two well-characterized neurodegenerative disorders—Alzheimer's disease (AD) and diffuse Lewy body

Payam Rezaie; Charlie C. Pontikis; Lance Hudson; Nigel J. Cairns; Peter L. Lantos

2005-01-01

95

Evidence for intact local connectivity but disrupted regional function in the occipital lobe in children and adolescents with schizophrenia  

PubMed Central

It has long been known that specific visual frequencies result in greater blood flow to the striate cortex. These peaks are thought to reflect synchrony of local neuronal firing that is reflective of local cortical networks. Since disrupted neural connectivity is a possible etiology for schizophrenia, our goal was to investigate whether localized connectivity, as measured by aberrant synchrony, is abnormal in children and adolescents with schizophrenia. Subjects included 25 children and adolescents with schizophrenia and 39 controls matched for age and gender. Subjects were scanned on a Siemens 3 Tesla Trio scanner while observing flashing checkerboard presented at either 1, 4, 8, or 12 Hz. Image processing included both a standard GLM model and a Fourier transform analysis. Patients had significantly smaller volume of activation in the occipital lobe compared to controls. There were no differences in the integral or percent signal change of the hemodynamic response function for each of the four frequencies. Occipital activation was stable during development between childhood and late adolescence. Finally, both patients and controls demonstrated an increased response between 4 and 8 Hz consistent with synchrony or entrainment in the neuronal response. Children and adolescents with schizophrenia had a significantly lower volume of activation in the occipital lobe in response to the flashing checkerboard task. However, features of intact local connectivity in patients, such as the hemodynamic response function and maximal response at 8 Hz, were normal. These results are consistent with abnormalities in regional connectivity with preserved local connectivity in early-onset schizophrenia. PMID:21674696

White, Tonya; Moeller, Steen; Schmidt, Marcus; Pardo, Jose V.; Olman, Cheryl

2011-01-01

96

A computed tomography morphometric study of occipital bone and C2 pedicle anatomy for occipital-cervical fusion  

PubMed Central

Background: Occipital-cervical fusion (OCF) has been used to treat instability of the occipito-cervical junction and to provide biomechanical stability after decompressive surgery. The specific areas that require detailed morphologic knowledge to prevent technical failures are the thickness of the occipital bone and diameter of the C2 pedicle, as the occipital midline bone and the C2 pedicle have structurally the strongest bone to provide the biomechanical purchase for cranio-cervical instrumentation. The aim of this study was to perform a quantitative morphometric analysis using computed tomography (CT) to determine the variability of the occipital bone thickness and C2 pedicle thickness to optimize screw placement for OCF in a South East Asian population. Methods: Thirty patients undergoing cranio-cervical junction instrumentation during the period 2008-2010 were included. The thickness of the occipital bone and the length and diameter of the C2 pedicle were measured based on CT. Results: The thickest point on the occipital bone was in the midline with a maximum thickness below the external occipital protuberance of 16.2 mm (±3.0 mm), which was thicker than in the Western population. The average C2 pedicle diameter was 5.3 mm (±2.0 mm). This was smaller than Western population pedicle diameters. The average length of the both pedicles to the midpoint of the C2 vertebral body was 23.5 mm (±3.3 mm on the left and ±2.3 mm on the right). Conclusions: The results of this first study in the South East Asian population should help guide and improve the safety in occipito-cervical region instrumentation. Thus reducing the risk of technical failures and neuro-vascular injury.

King, Nicolas K. K.; Rajendra, Tiruchelvarayan; Ng, Ivan; Ng, Wai Hoe

2014-01-01

97

Effects of different coatings on biochemical changes of ‘cat Hoa loc’ mangoes in storage  

Microsoft Academic Search

‘Cat Hoa loc’ mangoes (Mangifera indica, L.) were treated with five different coatings (TFC150, TFC210, Xedabio, Xedasol M23 and Bioxeda) and stored under ambient conditions (21–31°C and 65–75% RH). Two carnauba based coatings (TFC150 and TFC210) reduced mango weight loss. Xedabio retarded fruit ripening during storage, with smaller changes in the ripening indicators (peel and flesh colours, TA, pH, SSC,

Thai Thi Hoa; Marie-Noëlle Ducamp

2008-01-01

98

Feedback of pVisual Object Information to Foveal Retinotopic Cortex  

PubMed Central

The mammalian visual system contains an extensive web of feedback connections projecting from “higher” cortical areas to “lower” areas including primary visual cortex. Although multiple theories have been proposed, the role of these connections in perceptual processing is not understood. Here we report a surprising new phenomenon not predicted by prior theories of feedback: the pattern of fMRI response in human foveal retinotopic cortex contains information about objects presented in the periphery, far away from the fovea. This information is position invariant, correlated with perceptual discrimination accuracy, and found only in foveal, not peripheral, retinotopic cortex. Our data cannot be explained by differential eye movements, activation from the fixation cross, or spillover activation from peripheral retinotopic cortex or from LOC. Instead, our findings indicate that position-invariant object information from higher cortical areas is fed back to foveal retinotopic cortex, enhancing task performance. PMID:18978780

Williams, Mark A.; Baker, Chris I.; Op de Beeck, Hans P.; Shim, Won Mok; Dang, Sabin; Triantafyllou, Christina; Kanwisher, Nancy

2009-01-01

99

Occipital peripheral nerve stimulation in the management of chronic intractable occipital neuralgia in a patient with neurofibromatosis type 1: a case report  

Microsoft Academic Search

Introduction  Occipital peripheral nerve stimulation is an interventional pain management therapy that provides beneficial results in the\\u000a treatment of refractory chronic occipital neuralgia. Herein we present a first-of-its-kind case study of a patient with neurofibromatosis\\u000a type 1 and bilateral occipital neuralgia treated with occipital peripheral nerve stimulation.\\u000a \\u000a \\u000a \\u000a \\u000a Case presentation  A 42-year-old Caucasian woman presented with bilateral occipital neuralgia refractory to various conventional

Ioannis Skaribas; Octavio Calvillo; Evangelia Delikanaki-Skaribas

2011-01-01

100

LocARNAscan: Incorporating thermodynamic stability in sequence and structure-based RNA homology search  

PubMed Central

Background The search for distant homologs has become an import issue in genome annotation. A particular difficulty is posed by divergent homologs that have lost recognizable sequence similarity. This same problem also arises in the recognition of novel members of large classes of RNAs such as snoRNAs or microRNAs that consist of families unrelated by common descent. Current homology search tools for structured RNAs are either based entirely on sequence similarity (such as blast or hmmer) or combine sequence and secondary structure. The most prominent example of the latter class of tools is Infernal. Alternatives are descriptor-based methods. In most practical applications published to-date, however, the information contained in covariance models or manually prescribed search patterns is dominated by sequence information. Here we ask two related questions: (1) Is secondary structure alone informative for homology search and the detection of novel members of RNA classes? (2) To what extent is the thermodynamic propensity of the target sequence to fold into the correct secondary structure helpful for this task? Results Sequence-structure alignment can be used as an alternative search strategy. In this scenario, the query consists of a base pairing probability matrix, which can be derived either from a single sequence or from a multiple alignment representing a set of known representatives. Sequence information can be optionally added to the query. The target sequence is pre-processed to obtain local base pairing probabilities. As a search engine we devised a semi-global scanning variant of LocARNA’s algorithm for sequence-structure alignment. The LocARNAscan tool is optimized for speed and low memory consumption. In benchmarking experiments on artificial data we observe that the inclusion of thermodynamic stability is helpful, albeit only in a regime of extremely low sequence information in the query. We observe, furthermore, that the sensitivity is bounded in particular by the limited accuracy of the predicted local structures of the target sequence. Conclusions Although we demonstrate that a purely structure-based homology search is feasible in principle, it is unlikely to outperform tools such as Infernal in most application scenarios, where a substantial amount of sequence information is typically available. The LocARNAscan approach will profit, however, from high throughput methods to determine RNA secondary structure. In transcriptome-wide applications, such methods will provide accurate structure annotations on the target side. Availability Source code of the free software LocARNAscan 1.0 and supplementary data are available at http://www.bioinf.uni-leipzig.de/Software/LocARNAscan. PMID:23601347

2013-01-01

101

Visual recovery after surgical decompression of an occipital intraventricular cyst.  

PubMed

: A 62-year-old woman presented with a chronic left homonymous visual field defect because of a right occipital cyst. Serial visual field examination documented stable visual fields for 12 months, after which there was worsening of visual fields associated with enlargement of the cyst. Surgical decompression of the occipital cyst resulted in marked improvement of the visual field defect over 9 months. This case demonstrates that surgical decompression of cystic lesions adjacent to posterior visual pathways can result in recovery of chronic visual field loss. PMID:24897008

Vedantam, Aditya; Yoshor, Daniel; Foroozan, Rod

2014-09-01

102

Remapping in Human Visual Cortex  

PubMed Central

With each eye movement, stationary objects in the world change position on the retina, yet we perceive the world as stable. Spatial updating, or remapping, is one neural mechanism by which the brain compensates for shifts in the retinal image caused by voluntary eye movements. Remapping of a visual representation is believed to arise from a widespread neural circuit including parietal and frontal cortex. The current experiment tests the hypothesis that extrastriate visual areas in human cortex have access to remapped spatial information. We tested this hypothesis using functional magnetic resonance imaging (fMRI). We first identified the borders of several occipital lobe visual areas using standard retinotopic techniques. We then tested subjects while they performed a single-step saccade task analogous to the task used in neurophysiological studies in monkeys, and two conditions that control for visual and motor effects. We analyzed the fMRI time series data with a nonlinear, fully Bayesian hierarchical statistical model. We identified remapping as activity in the single-step task that could not be attributed to purely visual or oculomotor effects. The strength of remapping was roughly monotonic with position in the visual hierarchy: remapped responses were largest in areas V3A and hV4 and smallest in V1 and V2. These results demonstrate that updated visual representations are present in cortical areas that are directly linked to visual perception. PMID:17093130

Merriam, Elisha P.; Genovese, Christopher R.; Colby, Carol L.

2008-01-01

103

Repetition Suppression for Speech Processing in the Associative Occipital and Parietal Cortex of Congenitally  

E-print Network

transfer of specific adaptive properties across neural regions as a consequence of sensory deprivation Laboratories, New Haven, Connecticut, United States of America Abstract In the congenitally blind (CB), sensory deprivation results in cross-modal plasticity, with visual cortical activity observed for various auditory

104

Cerebral Cortex January 2010;20:130--140 doi:10.1093/cercor/bhp085  

E-print Network

variability. We have developed a method for aligning the functional neuroanatomy of individual brains based surface. The method, although developed using movie data, generalizes success- fully to data obtained or the lateral occipital sulcus (Tootell et al. 1995). Moreover, the primary visual cortex, area V1, can vary

Sabuncu, Mert Rory

105

Traumatic aneurysm of the occipital artery secondary to paintball injury  

Microsoft Academic Search

Paintball is an “extreme sport” that has been steadily growing in popularity since the early 1980s. Although this activity is considered recreational, there are a number of inherent dangers associated. Most notably, the number of head and neck injuries due to paintball participation has been increasing in recent years. In this paper we present the first reported case of occipital

Neely John; James L. Leach; Tyagi Rachana; Francesco T. Mangano

2009-01-01

106

RESEARCH REPORT Occipital gamma activation during Vipassana meditation  

E-print Network

RESEARCH REPORT Occipital gamma activation during Vipassana meditation B. Rael Cahn � Arnaud Long-term Vipassana meditators sat in medi- tation vs. a control rest (mind-wandering) state for 21 min in a counterbalanced design with spontaneous EEG recor- ded. Meditation state dynamics were measured with spec- tral

107

RESEARCH REPORT Occipital gamma activation during Vipassana meditation  

E-print Network

RESEARCH REPORT Occipital gamma activation during Vipassana meditation B. Rael Cahn · Arnaud. This article is published with open access at Springerlink.com Abstract Long-term Vipassana meditators sat with spontaneous EEG recor- ded. Meditation state dynamics were measured with spec- tral decomposition of the last

Delorme, Arnaud

108

Delayed posttraumatic unilateral occipital epidural hygroma in early childhood.  

PubMed

An extremely rare case of posttraumatic epidural hygroma in the left occipital supratentorial and infratentorial region is reported. A year and five months old child was admitted to the Clinic of Neurosurgery with sustained occipital head injury. She presented with drowsiness and vomiting due to intracranial hypertension. Initial computed tomography scan revealed left-sided fracture of the squamous part of the occipital bone without associated traumatic changes to the brain. A second spiral computed tomography scan was obtained two days later because of persisting symptoms of increased intracranial pressure. It demonstrated a newly formed left-sided epidural hygroma adjacent to the skull fracture in the left supratentorial and infratentorial occipital region. The case is discussed with emphasis on the mechanism of formation of epidural hygroma and an attempt has been made to outline the major predisposing factors leading to the development of this traumatic disease. Necessity for computed tomography follow-up is pointed out in order to diagnose delayed posttraumatic hygromas. The recommended surgical approach should include craniotomy centered at the site of the epidural hygroma and obligatory dural elevation by means of traction sutures to eliminate the posttraumatic epidural cavity. PMID:21644408

Kehayov, Ivo I; Batakliev, Ivan V; Kitov, Borislav D; Dichev, Alexander D

2011-01-01

109

Parietal Occipital Edema in Hypertensive Encephalopathy: A Pathogenic Mechanism  

Microsoft Academic Search

Eight patients with hypertensive encephalopathy from diverse etiologies developed cerebral edema in the vertebrobasilar distribution which resolved after blood pressure was lowered. Parietal occipital edema is a recognized feature of hypertensive encephalopathy. The explanation for this regional pathological variation in hypertensive encephalopathy remains undefined. Some evidence suggests that sympathetic innervation of the anterior cerebral vasculature may be protective, and conversely,

Raj D. Sheth; Jack E. Riggs; John B. Bodenstenier; Alvoro R. Gutierrez; Leena M. Ketonen; Orlando A. Ortiz

1996-01-01

110

Refractory headaches treated with bilateral occipital and temporal region stimulation  

PubMed Central

Objectives To describe use of bilateral temporal and occipital stimulator leads for a refractory headache disorder. Materials and methods A 31-year-old female had a 10-year history of chronic, severe occipital and temporal region headaches. The patient underwent permanent implant of an occipital stimulator system that resulted in sustained, compete resolution of her occipital pain. However, she continued to suffer disabling (10/10) temporal region headaches and was bedbound most days of the week. Therefore, bilateral temporal stimulator leads were implanted and tunneled to her internal pulse generator. Results At 12-month follow-up, the patient enjoyed sustained improvement in her pain scores (8/10) and marked increase in her level of functioning. Taking into account increased activity level, she rated her overall improvement at 50%. Unfortunately, infection and erosion of her right temporal lead necessitated temporal stimulator removal. Conclusion Headache disorders may require stimulation of all painful cephalic regions. However, our success in this case must be considered in light of the technical challenges and expense of placing stimulator leads subcutaneously around the head and neck, including the risk of infection, lead breakage, erosion, and migration. PMID:24707189

Zach, Kelly J; Trentman, Terrence L; Zimmerman, Richard S; Dodick, David W

2014-01-01

111

Occipital Transtentorial Approach and Combined Treatments for Pineal Parenchymal Tumors  

Microsoft Academic Search

The deep-seated location of pineal parenchymal tumors (PPTs) and their associations with critical structures make their surgical resection technically challenging; further, the rarity of PPTs and repeated changes in their histopathological diagnostic criteria makes the study of their biological behavior and clinical outcomes difficult. Here, we describe the surgical techniques and results of an occipital transtentorial approach for PPTs together

Itaru Tsumanuma; Ryuichi Tanaka; Yukihiko Fujii

2009-01-01

112

Benign Occipital Epilepsies of Childhood: Clinical Features and Genetics  

ERIC Educational Resources Information Center

The early and late benign occipital epilepsies of childhood (BOEC) are described as two discrete electro-clinical syndromes, eponymously known as Panayiotopoulos and Gastaut syndromes. Our aim was to explore the clinical features, classification and clinical genetics of these syndromes using twin and multiplex family studies to determine whether…

Taylor, Isabella; Berkovic, Samuel F.; Kivity, Sara; Scheffer, Ingrid E.

2008-01-01

113

The mendosal suture of the occipital bone: occurrence in Indian population, embryology and clinical significance  

Microsoft Academic Search

The Occipital occipital bone is ontogenetically and functionally unique when compared to the other bones of the skull in humans\\u000a and other mammalian cousins. The Occipital occipital bone develops from six ossification centers; any defect in the ossification\\u000a process will give rise to mendosal suture (accessory suture) and conditions like posterior plagiocephaly. There is a paucity\\u000a of literature regarding the

Soubhagya R. Nayak; Ashwin Krishnamurthy; S. J. Madhan Kumar; Latha V. Prabhu; P. J. Jiji; Mangala M. Pai; Arunachalam Kumar; Ramakrishna Avadhani

2007-01-01

114

Epi2Loc: an R package to investigate two-locus epistatic models.  

PubMed

Epistasis is a growing area of research in genome-wide studies, but the differences between alternative definitions of epistasis remain a source of confusion for many researchers. One problem is that models for epistasis are presented in a number of formats, some of which have difficult-to-interpret parameters. In addition, the relation between the different models is rarely explained. Existing software for testing epistatic interactions between single-nucleotide polymorphisms (SNPs) does not provide the flexibility to compare the available model parameterizations. For that reason we have developed an R package for investigating epistatic and penetrance models, Epi2Loc, to aid users who wish to easily compare, interpret, and utilize models for two-locus epistatic interactions. Epi2Loc facilitates research on SNP-SNP interactions by allowing the R user to easily convert between common parametric forms for two-locus interactions, generate data for simulation studies, and perform power analyses for the selected model with a continuous or dichotomous phenotype. The usefulness of the package for model interpretation and power analysis is illustrated using data on rheumatoid arthritis. PMID:24983251

Walters, Raymond K; Laurin, Charles; Lubke, Gitta H

2014-08-01

115

Gyrokinetic Simulations of Diluted Plasmas in the LOC regime in Alcator C-Mod  

NASA Astrophysics Data System (ADS)

Previous investigations of ITG and TEM/ETG turbulence using the reduced gyro-landau fluid code TGLF, and gyrokinetic code GYRO have predicted that in the linear ohmic confinement (LOC) regime in Alcator C-Mod the dilution of the main D ion species by low-Z impurities reduces the ion transport to experimentally observed levels. This analysis assumed an average impurity ion charge Zi= 8. Recent spectroscopic measurements of the impurity ion species in the LOC regime in C-Mod have shown that the average Zi is approximately 9, which at the measured Zeff values (2-4) results in a significant dilution (>10%) of the majority D ion species. By puffing in nitrogen while using a cryopump to keep the density constant, new experiments enabled us to lower Zi to values near 8, thus further increasing dilution. To account for the sensitivity of the turbulent transport on the density (Lne) and temperature (LTe) gradient scale lengths, recently we used TGYRO to improve the agreement between theory and the measurements. The results of such simulations will be presented.

Porkolab, M.; Ennever, P.; Reinke, M. L.; Rice, J.; Rost, C.; Tsujii, N.; Davis, E.; Ernst, D.; Fiore, C.; Greenwald, M.; Hubbard, A.; Hughes, J.; Marmar, E.; Candy, J.; Staebler, G. M.; Waltz, R.

2012-10-01

116

Occipital horn syndrome in a woman: skeletal radiological findings  

Microsoft Academic Search

Ehlers–Danlos type IX syndrome, also called occipital horn syndrome (OHS), is a milder and rare form of Menkes disease where\\u000a the patient reaches adulthood. As an X-linked disease, it typically occurs in male subjects, while female subjects are usually\\u000a healthy carriers. OHS is mainly characterized by connective tissue disorders and slightly subnormal intelligence or signs\\u000a of autonomic dysfunction are the

Alberto Bazzocchi; Rayka Femia; Paola Feraco; Giuseppe Battista; Romeo Canini; Giuseppe Guglielmi

117

Cytoarchitectonic mapping of the human dorsal extrastriate cortex.  

PubMed

The dorsal visual stream consists of several functionally specialized areas, but most of their cytoarchitectonic correlates have not yet been identified in the human brain. The cortex adjacent to Brodmann area 18/V2 was therefore analyzed in serial sections of ten human post-mortem brains using morphometrical and multivariate statistical analyses for the definition of areal borders. Two previously unknown cytoarchitectonic areas (hOc3d, hOc4d) were detected. They occupy the medial and, to a smaller extent, lateral surface of the occipital lobe. The larger area, hOc3d, is located dorso-lateral to area V2 in the region of superior and transverse occipital, as well as parieto-occipital sulci. Area hOc4d was identified rostral to hOc3d; it differed from the latter by larger pyramidal cells in lower layer III, thinner layers V and VI, and a sharp cortex-white-matter borderline. The delineated areas were superimposed in the anatomical MNI space, and probabilistic maps were calculated. They show a relatively high intersubject variability in volume and position. Based on their location and neighborhood relationship, areas hOc3d and hOc4d are putative anatomical substrates of functionally defined areas V3d and V3a, a hypothesis that can now be tested by comparing probabilistic cytoarchitectonic maps and activation studies of the living human brain. PMID:22354469

Kujovic, Milenko; Zilles, Karl; Malikovic, Aleksandar; Schleicher, Axel; Mohlberg, Hartmut; Rottschy, Claudia; Eickhoff, Simon B; Amunts, Katrin

2013-01-01

118

iLoc-Euk: A Multi-Label Classifier for Predicting the Subcellular Localization of Singleplex and Multiplex Eukaryotic Proteins  

PubMed Central

Predicting protein subcellular localization is an important and difficult problem, particularly when query proteins may have the multiplex character, i.e., simultaneously exist at, or move between, two or more different subcellular location sites. Most of the existing protein subcellular location predictor can only be used to deal with the single-location or “singleplex” proteins. Actually, multiple-location or “multiplex” proteins should not be ignored because they usually posses some unique biological functions worthy of our special notice. By introducing the “multi-labeled learning” and “accumulation-layer scale”, a new predictor, called iLoc-Euk, has been developed that can be used to deal with the systems containing both singleplex and multiplex proteins. As a demonstration, the jackknife cross-validation was performed with iLoc-Euk on a benchmark dataset of eukaryotic proteins classified into the following 22 location sites: (1) acrosome, (2) cell membrane, (3) cell wall, (4) centriole, (5) chloroplast, (6) cyanelle, (7) cytoplasm, (8) cytoskeleton, (9) endoplasmic reticulum, (10) endosome, (11) extracellular, (12) Golgi apparatus, (13) hydrogenosome, (14) lysosome, (15) melanosome, (16) microsome (17) mitochondrion, (18) nucleus, (19) peroxisome, (20) spindle pole body, (21) synapse, and (22) vacuole, where none of proteins included has pairwise sequence identity to any other in a same subset. The overall success rate thus obtained by iLoc-Euk was 79%, which is significantly higher than that by any of the existing predictors that also have the capacity to deal with such a complicated and stringent system. As a user-friendly web-server, iLoc-Euk is freely accessible to the public at the web-site http://icpr.jci.edu.cn/bioinfo/iLoc-Euk. It is anticipated that iLoc-Euk may become a useful bioinformatics tool for Molecular Cell Biology, Proteomics, System Biology, and Drug Development Also, its novel approach will further stimulate the development of predicting other protein attributes. PMID:21483473

Chou, Kuo-Chen; Wu, Zhi-Cheng; Xiao, Xuan

2011-01-01

119

iLoc-Euk: a multi-label classifier for predicting the subcellular localization of singleplex and multiplex eukaryotic proteins.  

PubMed

Predicting protein subcellular localization is an important and difficult problem, particularly when query proteins may have the multiplex character, i.e., simultaneously exist at, or move between, two or more different subcellular location sites. Most of the existing protein subcellular location predictor can only be used to deal with the single-location or "singleplex" proteins. Actually, multiple-location or "multiplex" proteins should not be ignored because they usually posses some unique biological functions worthy of our special notice. By introducing the "multi-labeled learning" and "accumulation-layer scale", a new predictor, called iLoc-Euk, has been developed that can be used to deal with the systems containing both singleplex and multiplex proteins. As a demonstration, the jackknife cross-validation was performed with iLoc-Euk on a benchmark dataset of eukaryotic proteins classified into the following 22 location sites: (1) acrosome, (2) cell membrane, (3) cell wall, (4) centriole, (5) chloroplast, (6) cyanelle, (7) cytoplasm, (8) cytoskeleton, (9) endoplasmic reticulum, (10) endosome, (11) extracellular, (12) Golgi apparatus, (13) hydrogenosome, (14) lysosome, (15) melanosome, (16) microsome (17) mitochondrion, (18) nucleus, (19) peroxisome, (20) spindle pole body, (21) synapse, and (22) vacuole, where none of proteins included has ?25% pairwise sequence identity to any other in a same subset. The overall success rate thus obtained by iLoc-Euk was 79%, which is significantly higher than that by any of the existing predictors that also have the capacity to deal with such a complicated and stringent system. As a user-friendly web-server, iLoc-Euk is freely accessible to the public at the web-site http://icpr.jci.edu.cn/bioinfo/iLoc-Euk. It is anticipated that iLoc-Euk may become a useful bioinformatics tool for Molecular Cell Biology, Proteomics, System Biology, and Drug Development Also, its novel approach will further stimulate the development of predicting other protein attributes. PMID:21483473

Chou, Kuo-Chen; Wu, Zhi-Cheng; Xiao, Xuan

2011-01-01

120

[Decreased occipital GABA concentrations in patients with first-episode major depressive disorder: a magnetic resonance spectroscopy study].  

PubMed

Gamma amino butyric acid (GABA) is the major inhibitory neurotransmitter in the human brain. Alterations in GABAergic function are associated with a variety of neurological and psychiatric disorders. However, noninvasive in vivo measurement of GABA is difficult because of its low concentration and the presence of overlapping resonances. To study GABA concentration in the occipital cortex in major depressive disorder (MDD), a group of medication-naive, first episode depressed patients (n = 18, HAMD > 17), and a group of healthy controls (n = 23) were investigated using a Point Resolved Spectroscopy (MEGA-PRESS) on a 3.0 T MR scanner. The results showed that occipital GABA levels were significantly lower (P < 0.001) in the patient group than those in the healthy controls, yet the correlations between the severity of MDD (HAMD, BDI) and the GABA concentration is insignificant. Therefore, our data suggest that patients with first episode, unmedicated MDD have changes in cortical concentrations of GABA. This biochemical abnormality may be a marker of a trait vulnerability to mood disorder, and may explain the visual problem of severe MDD patients. PMID:22616164

Song, Zhe; Huang, Peiyu; Qiu, Lihua; Wu, Qizhu; Gong, Qiyong; Zhang, Bida; Heberlein, Keith; Xie, Peng

2012-04-01

121

Peritrigonal and temporo-occipital heterotopia with corpus callosum and cerebellar dysgenesis  

PubMed Central

Objective: To describe a homogeneous subtype of periventricular nodular heterotopia (PNH) as part of a newly defined malformation complex. Methods: Observational study including review of brain MRI and clinical findings of a cohort of 50 patients with PNH in the temporo-occipital horns and trigones, mutation analysis of the FLNA gene, and anatomopathologic study of a fetal brain. Results: There were 28 females and 22 males. All were sporadic with the exception of an affected mother and son. Epilepsy occurred in 62%, cerebellar signs in 56%, cognitive impairment in 56%, and autism in 12%. Seventy percent were referred within the 3rd year of life. Imaging revealed a normal cerebral cortex in 76% and abnormal cortical folding in 24%. In all patients the hippocampi were under-rotated and in 10% they merged with the heterotopia. Cerebellar dysgenesis was observed in 84% and a hypoplastic corpus callosum in 60%. There was no gender bias or uneven gender distribution of clinical and anatomic severity. No mutations of FLNA occurred in 33 individuals examined. Heterotopia in the fetal brain revealed cytoarchitectonic characteristics similar to those associated with FLNA mutations; cortical pathology was not typical of polymicrogyria. Cerebellar involvement was more severe and the hippocampi appeared simple and under-rotated. Conclusions: This series delineates a malformation complex in which PNH in the trigones and occipito-temporal horns is associated with hippocampal, corpus callosum, and cerebellar dysgenesis. This subtype of PNH is distinct from classic PNH caused by FLNA mutations. PMID:22914838

Pisano, Tiziana; Barkovich, A. James; Leventer, Richard J.; Squier, Waney; Scheffer, Ingrid E.; Parrini, Elena; Blaser, Susan; Marini, Carla; Robertson, Stephen; Tortorella, Gaetano; Rosenow, Felix; Thomas, Pierre; McGillivray, George; Andermann, Eva; Andermann, Frederick; Berkovic, Samuel F.; Dobyns, William B.

2012-01-01

122

Longterm stability and developmental changes in spontaneous network burst firing patterns in dissociated rat cerebral cortex cell cultures on  

E-print Network

from dissociated rat occipital cortex cells cultured on planar multi-electrode plates, during their development from isolated neurons into synaptically connected neuronal networks. Activity typically consisted a month in vitro these cultured neuronal networks have developed a degree of excitability that allows

van Pelt, Jaap

123

Differential Sensitivity of Human Visual Cortex to Faces, Letterstrings, and Textures: A Functional Magnetic Resonance Imaging Study  

Microsoft Academic Search

Twelve normal subjects viewed alternating sequences of unfa- miliar faces, unpronounceable nonword letterstrings, and tex- tures while echoplanar functional magnetic resonance images were acquired in seven slices extending from the posterior margin of the splenium to near the occipital pole. These stimuli were chosen to elicit initial category-specific processing in extrastriate cortex while minimizing semantic processing. Over- all, faces evoked

Aina Puce; Truett Allison; Maryam Asgari; John C. Gore; Gregory McCarthy

1996-01-01

124

The human cerebral cortex flattens during adolescence.  

PubMed

The human cerebral cortex appears to shrink during adolescence. To delineate the dynamic morphological changes involved in this process, 52 healthy male and female adolescents (11-17 years old) were neuroimaged twice using magnetic resonance imaging, approximately 2 years apart. Using a novel morphometric analysis procedure combining the FreeSurfer and BrainVisa image software suites, we quantified global and lobar change in cortical thickness, outer surface area, the gyrification index, the average Euclidean distance between opposing sides of the white matter surface (gyral white matter thickness), the convex ("exposed") part of the outer cortical surface (hull surface area), sulcal length, depth, and width. We found that the cortical surface flattens during adolescence. Flattening was strongest in the frontal and occipital cortices, in which significant sulcal widening and decreased sulcal depth co-occurred. Globally, sulcal widening was associated with cortical thinning and, for the frontal cortex, with loss of surface area. For the other cortical lobes, thinning was related to gyral white matter expansion. The overall flattening of the macrostructural three-dimensional architecture of the human cortex during adolescence thus involves changes in gray matter and effects of the maturation of white matter. PMID:24048830

Alemán-Gómez, Yasser; Janssen, Joost; Schnack, Hugo; Balaban, Evan; Pina-Camacho, Laura; Alfaro-Almagro, Fidel; Castro-Fornieles, Josefina; Otero, Soraya; Baeza, Immaculada; Moreno, Dolores; Bargalló, Nuria; Parellada, Mara; Arango, Celso; Desco, Manuel

2013-09-18

125

TECHNICAL NOTE www.rsc.org/loc | Lab on a Chip Neutravidin micropatterning by deep UV irradiation  

E-print Network

TECHNICAL NOTE www.rsc.org/loc | Lab on a Chip Neutravidin micropatterning by deep UV irradiation February 2008, Accepted 16th June 2008 First published as an Advance Article on the web 13th August 2008 by exposure to deep UV irradiation. Neutravidin is physically absorbed onto the glass or quartz substrate

Hancock, William O.

126

PAPER www.rsc.org/loc | Lab on a Chip A platform for assessing chemotactic migration within a spatiotemporally  

E-print Network

PAPER www.rsc.org/loc | Lab on a Chip A platform for assessing chemotactic migration within a spatiotemporally defined 3D microenvironment Vinay V. Abhyankar, Michael W. Toepke, Christa L. Cortesio, Mary A of cell movement within defined biochemical gradients is now possible with microfluidic approaches

Beebe, David J.

127

www.rsc.org/loc Volume8|Number4|April2008|Pages501632 ISSN1473-0197  

E-print Network

www.rsc.org/loc | Lab on a Chip Rapid, continuous purification of proteins in a microfluidic device of an integrated lab-on-a-chip device comprising cell culture, lysis, purification and analysis on a single device, including an inherent ability to process small volumes, precise control Sandia National Laboratories

Singh, Anup

128

Traumatic aneurysm of the occipital artery secondary to paintball injury.  

PubMed

Paintball is an "extreme sport" that has been steadily growing in popularity since the early 1980s. Although this activity is considered recreational, there are a number of inherent dangers associated. Most notably, the number of head and neck injuries due to paintball participation has been increasing in recent years. In this paper we present the first reported case of occipital artery traumatic pseudoaneurysm resulting from a paintball accident. The presentation, diagnosis and intraoperative findings are detailed. A discussion including a review of the literature is also presented. The authors recommend a re-evaluation of guidelines within the paintball sporting industry, including improvements in protective equipment. PMID:18922630

John, Neely; Leach, James L; Rachana, Tyagi; Mangano, Francesco T

2009-01-01

129

The Intramuscular Course of the Greater Occipital Nerve: Novel Findings with Potential Implications for Operative Interventions and Occipital Neuralgia  

PubMed Central

Background: A better understanding of the etiologies of occipital neuralgia would help the clinician treat patients with this debilitating condition. Since few studies have examined the muscular course of the greater occipital nerve (GON), this study was performed. Methods: Thirty adult cadaveric sides underwent dissection of the posterior occiput with special attention to the intramuscular course of the GON. Nerves were typed based on their muscular course. Results: The GON traveled through the trapezius (type I; n = 5, 16.7%) or its aponeurosis (type II; n = 15, 83.3%) to become subcutaneous. Variations in the subtrapezius muscular course were found in 10 (33%) sides. In two (6.7%) sides, the GON traveled through the lower edge of the inferior capitis oblique muscle (subtype a). On five (16.7%) sides, the GON coursed through a tendinous band of the semispinalis capitis, not through its muscular fibers (subtype b). On three (10%) sides the GON bypassed the semispinalis capitis muscle to travel between its most medial fibers and the nuchal ligament (subtype c). For subtypes, eight were type II courses (through the aponeurosis of the trapezius), and two were type I courses (through the trapezius muscle). The authors identified two type IIa courses, four type IIb courses, and two type IIc courses. Type I courses included one type Ib and one type Ic courses. Conclusions: Variations in the muscular course of the GON were common. Future studies correlating these findings with the anatomy in patients with occipital neuralgia may elucidate nerve courses vulnerable to nerve compression. This enhanced classification scheme describes the morphology in this region and allows more specific communications about GON variations.

Tubbs, R. Shane; Watanabe, Koichi; Loukas, Marios; Cohen-Gadol, Aaron A.

2014-01-01

130

Neuropsychological profile of adult patients with nonsymptomatic occipital lobe epilepsies.  

PubMed

To explore the neuropsychological and neurobehavioral profile in adult patients affected by nonsymptomatic (cryptogenic and idiopathic) occipital lobe epilepsy (OLE), with normal intelligence, we enrolled 20 adult patients with nonsymptomatic OLE and 20 age-, sex-, and education-matched healthy subjects. All participants underwent neuropsychiatric assessment scales, and standardized neuropsychological tests tapping memory, executive functions, constructional, visuospatial and visuoperceptual skills. After Bonferroni correction for multiple comparisons, patients performed significantly worse than controls on several tests tapping complex visuospatial skills and frontal lobe functions. The analysis of single patients' performance revealed that a significantly higher number of OLE patients achieved age- and education-adjusted pathological scores on three tests (Benton Judgment of Line Orientation Test, Freehand Copying of Drawings Test, color-word interference task of Stroop test) with respect to controls. Patients did not differ from control subjects on neuropsychiatric aspects. The direct comparison between OLE subtypes showed that cryptogenetic OLE patients tended to achieve lower scores than idiopathic OLE patients on most tests, but no difference between the two groups was fully significant. In summary, patients with nonsymptomatic OLE can be affected by clinically relevant impairments in selected neuropsychological domains: complex visuospatial skills and executive functions. It could be speculated that frontal and visuospatial cognitive deficits might be the result of epileptic activity spreading within a neural network that includes structures far beyond the occipital lobe. PMID:22903808

Bilo, Leonilda; Santangelo, Gabriella; Improta, Ilaria; Vitale, Carmine; Meo, Roberta; Trojano, Luigi

2013-02-01

131

The causal role of the lateral occipital complex in visual mirror symmetry detection and grouping: an fMRI-guided TMS study.  

PubMed

Despite the fact that bilateral mirror symmetry is an important characteristic of the visual world, few studies have investigated its neural basis. Here we addressed this issue by investigating whether the object-selective lateral occipital (LO) cortex, a key brain region in object and shape processing, is causally involved in bilateral symmetry detection. Participants were asked to discriminate between symmetric and asymmetric dot patterns, while fMRI-guided repetitive TMS was delivered online over either the left LO, the right LO or two control sites in the occipital cortex. We found that the application of TMS over both right and left LO impaired symmetry judgments, with disruption being greater following right LO than left LO TMS, indicative of right hemisphere lateralization in symmetry processing. TMS over LO bilaterally also affected a visual contour detection task, with no evidence for hemispheric difference in this task. Overall, our results demonstrates that LO bilaterally plays a causal role in symmetry detection possibly due to symmetry acting as a strong cue in Gestalt processes mediating object recognition. PMID:24360359

Bona, Silvia; Herbert, Andrew; Toneatto, Carlo; Silvanto, Juha; Cattaneo, Zaira

2014-02-01

132

Suture material for flexor tendon repair: 3–0 V-Loc versus 3–0 Stratafix in a biomechanical comparison ex vivo  

PubMed Central

Background Barbed suture material offers the possibility of knotless flexor tendon repair, as suggested in an increasing number of biomechanical studies. There are currently two different absorbable barbed suture products available, V-Loc™ and Stratafix™, and both have not been compared to each other with regard to flexor tendon repair. The purpose of this study was to evaluate both suture materials for primary stability under static and cyclic loading in a biomechanical ex vivo model. Methods Forty fresh porcine flexor digitorum profundus tendons were randomized in two groups. A four-strand modified Kessler suture technique was used to repair the tendon either with a 3–0 V-Loc™ or 3–0 Stratafix™ without a knot. Parameters of interest were mode of failure, 2-mm gap formation force, displacement, stiffness and maximum load under static and cyclic testing. Results The maximum load was 42.3?±?7.2 for the Stratafix™ group and 50.7?±?8.8 N for the V-Loc™ group. Thus, the ultimate tensile strength was significantly higher for V-Loc™ (p?Loc™ group (n.s.). Displacement was 2.65?±?0.56 mm in the V-Loc™ group and 2.71?±?0.59 mm in the Stratafix™ group (n.s.). Stiffness was 4.24?±?0.68 (N/mm) in the V-Loc™ group and 3.85?±?0.55 (N/mm) the Stratafix™ group (n.s.). Those measured differences were not significant. Conclusion V-Loc™ demonstrates a higher maximum load in tendon reconstruction. The differences in 2-mm gap formation force, displacement and stiffness were not significant. Hereby, the V-Loc™ has an advantage when used as unidirectional barbed suture for knotless flexor tendon repair. PMID:25205062

2014-01-01

133

Spheno-occipital synchondrosis fusion in modern Americans.  

PubMed

This study examines spheno-occipital synchondrosis fusion in the modern American population and presents age ranges for forensic use. The sample includes 162 modern individuals aged 5-25 years. The basilar synchondrosis was scored as open, closing, or closed via direct inspection of the ectocranial site of the suture. Transition analysis was used to determine the average ages at which an individual transitions from unfused to fusing and from fusing to fused. The maximum likelihood estimates from the transition analysis indicate that females are most likely to transition from open to closing at 11.4 years and males at 16.5 years. Females transition from closing to closed at 13.7 years and males at 17.4 years. The probability distributions associated with these maximum likelihood estimates were used to derive age ranges for age estimation purposes. These results reflect sexual dimorphism in basilar synchondrosis fusion and agree approximately with average age at pubertal onset. PMID:21361933

Shirley, Natalie R; Jantz, Richard L

2011-05-01

134

Changes in Cerebral Cortex of Children Treated for Medulloblastoma  

SciTech Connect

Purpose: Children with medulloblastoma undergo surgery, radiotherapy, and chemotherapy. After treatment, these children have numerous structural abnormalities. Using high-resolution magnetic resonance imaging, we measured the thickness of the cerebral cortex in a group of medulloblastoma patients and a group of normally developing children. Methods and Materials: We obtained magnetic resonance imaging scans and measured the cortical thickness in 9 children after treatment of medulloblastoma. The measurements from these children were compared with the measurements from age- and gender-matched normally developing children previously scanned. For additional comparison, the pattern of thickness change was compared with the cortical thickness maps from a larger group of 65 normally developing children. Results: In the left hemisphere, relatively thinner cortex was found in the perirolandic region and the parieto-occipital lobe. In the right hemisphere, relatively thinner cortex was found in the parietal lobe, posterior superior temporal gyrus, and lateral temporal lobe. These regions of cortical thinning overlapped with the regions of cortex that undergo normal age-related thinning. Conclusion: The spatial distribution of cortical thinning suggested that the areas of cortex that are undergoing development are more sensitive to the effects of treatment of medulloblastoma. Such quantitative methods may improve our understanding of the biologic effects that treatment has on the cerebral development and their neuropsychological implications.

Liu, Arthur K. [Harvard Combined Radiation Oncology Program, Harvard Medical School, Boston, MA (United States)]. E-mail: aliu1@partners.org; Marcus, Karen J. [Department of Radiation Oncology, Children's Hospital Boston, Harvard Medical School, Boston, MA (United States); Department of Radiation Oncology, Dana Farber Cancer Institute, Harvard Medical School, Boston, MA (United States); Department of Radiation Oncology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA (United States); Fischl, Bruce [Athinoula A. Martinos Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA (United States); Department of Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Division of Health Sciences and Technology, Cambridge, MA (United States); Grant, P. Ellen [Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA (United States); Young Poussaint, Tina [Department of Radiology, Children's Hospital Boston, Harvard Medical School, Boston, MA (United States); Rivkin, Michael J. [Departments of Neurology, Psychiatry, and Radiology, Children's Hospital Boston, Harvard Medical School, Boston, MA (United States); Davis, Peter [Departments of Neurology, Psychiatry, and Radiology, Children's Hospital Boston, Harvard Medical School, Boston, MA (United States); Tarbell, Nancy J. [Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA (United States); Yock, Torunn I. [Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA (United States)

2007-07-15

135

Preferential effect of isoflurane on top-down vs. bottom-up pathways in sensory cortex  

PubMed Central

The mechanism of loss of consciousness (LOC) under anesthesia is unknown. Because consciousness depends on activity in the cortico-thalamic network, anesthetic actions on this network are likely critical for LOC. Competing theories stress the importance of anesthetic actions on bottom-up “core” thalamo-cortical (TC) vs. top-down cortico-cortical (CC) and matrix TC connections. We tested these models using laminar recordings in rat auditory cortex in vivo and murine brain slices. We selectively activated bottom-up vs. top-down afferent pathways using sensory stimuli in vivo and electrical stimulation in brain slices, and compared effects of isoflurane on responses evoked via the two pathways. Auditory stimuli in vivo and core TC afferent stimulation in brain slices evoked short latency current sinks in middle layers, consistent with activation of core TC afferents. By contrast, visual stimuli in vivo and stimulation of CC and matrix TC afferents in brain slices evoked responses mainly in superficial and deep layers, consistent with projection patterns of top-down afferents that carry visual information to auditory cortex. Responses to auditory stimuli in vivo and core TC afferents in brain slices were significantly less affected by isoflurane compared to responses triggered by visual stimuli in vivo and CC/matrix TC afferents in slices. At a just-hypnotic dose in vivo, auditory responses were enhanced by isoflurane, whereas visual responses were dramatically reduced. At a comparable concentration in slices, isoflurane suppressed both core TC and CC/matrix TC responses, but the effect on the latter responses was far greater than on core TC responses, indicating that at least part of the differential effects observed in vivo were due to local actions of isoflurane in auditory cortex. These data support a model in which disruption of top-down connectivity contributes to anesthesia-induced LOC, and have implications for understanding the neural basis of consciousness. PMID:25339873

Raz, Aeyal; Grady, Sean M.; Krause, Bryan M.; Uhlrich, Daniel J.; Manning, Karen A.; Banks, Matthew I.

2014-01-01

136

Combined occipital and supraorbital neurostimulation for the treatment of chronic migraine headaches: Initial experience  

Microsoft Academic Search

A novel approach to the treatment of chronic migraine headaches based on neurostimulation of both occipital and supraorbital nerves was developed and reduced to clinical practice in a series of patients with headaches unresponsive to currently available therapies. Following positive trials, seven patients with chronic migraine and refractory chronic migraine headaches had permanent combined occipital nerve–supraorbital nerve neurostimulation systems implanted.

K L Reed; S B Black; C J Banta; K R Will

2010-01-01

137

Management of hydrocephalus associated with occipital encephalocoele using endoscopic third ventriculostomy: report of two cases  

Microsoft Academic Search

BACKGROUNDOccipital encephalocoele is the most common cranial dysraphism in the western hemisphere and is often complicated by hydrocephalus. Management of hydrocephalus and reducing the CSF pressure is crucial in preventing dehiscence at the site of the encephalocoele repair.METHODSTwo female patients had presented with occipital encephalocoeles. The first patient (aged 42 days) had undergone repair of the occipital encephalocoele and then

Ranjith K Moorthy; Vedantam Rajshekhar

2002-01-01

138

THREE-DIMENSIONAL PROBABILISTIC MAPS OF THE OCCIPITAL SULCI OF THE HUMAN BRAIN IN STANDARDIZED  

E-print Network

THREE-DIMENSIONAL PROBABILISTIC MAPS OF THE OCCIPITAL SULCI OF THE HUMAN BRAIN IN STANDARDIZED University Street, Montreal, Quebec, Canada H3A 2B4 Abstract--Developments in functional neuroimaging in nor mag- netic resonance images to investigate the morphological variation of the human occipital sulci

Iaria, Giuseppe

139

The Effect of Cataract Severity and Morphology on the Reliability of the Lens Opacities Classification System II (LOCS II)  

Microsoft Academic Search

Data collected from 3646 eyes in the Italian-American Natural History Study of Age-Related Cataract were used to investigate whether the reliability of the Lens Opacities Classification System II (LOCS II) by the severity of the opacity that is being graded or is influenced by the presence and severity of coexisting opacities. Reliability was assessed by comparing the slit-lamp gradings of

Giovanni Maraini; Paolo Pasquini; Robert D. Sperduto; Mirca Donacini; MariaParrizia Carrieri; Rosamaria Corona; Paolo Graziosi; MariaCarla Tomba; Sally L. Williams

140

SYNOSTOSIS OF ATLAS WITH OCCIPITAL BONE-OCCURRENCE AND CLINICAL APPLICATION.  

E-print Network

ABSTRACT: Synostosis also known as occipitalization of the atlas is a rare congenital malformation at craniovertebral junction. Atlas, the first cervical vertebra forms the ellipsoidal synovial joints with the condyles of the occipital bone. Rarely it gets occipitalized where the condyles fuse with the lateral masses of the atlas. During the morphometric study of hundred skulls in Department of Anatomy, Sri Guru Ram Das Institute of Medical Sciences and Research, Vallah, two skulls showed the incomplete occipitalization of the atlas vertebrae. The partial or complete assimilation of atlas may have resulted due to the disruption in the separation of caudal part of the first sclerotome from the cranial part of the first sclerotome. Key Words-Synostosis, Occipitalization, Ellipsoidal, Atlas.

Mahajan A

141

Dissociation of object and spatial visual processing pathways in human extrastriate cortex  

SciTech Connect

The existence and neuroanatomical locations of separate extrastriate visual pathways for object recognition and spatial localization were investigated in healthy young men. Regional cerebral blood flow was measured by positron emission tomography and bolus injections of H2(15)O, while subjects performed face matching, dot-location matching, or sensorimotor control tasks. Both visual matching tasks activated lateral occipital cortex. Face discrimination alone activated a region of occipitotemporal cortex that was anterior and inferior to the occipital area activated by both tasks. The spatial location task alone activated a region of lateral superior parietal cortex. Perisylvian and anterior temporal cortices were not activated by either task. These results demonstrate the existence of three functionally dissociable regions of human visual extrastriate cortex. The ventral and dorsal locations of the regions specialized for object recognition and spatial localization, respectively, suggest some homology between human and nonhuman primate extrastriate cortex, with displacement in human brain, possibly related to the evolution of phylogenetically newer cortical areas.

Haxby, J.V.; Grady, C.L.; Horwitz, B.; Ungerleider, L.G.; Mishkin, M.; Carson, R.E.; Herscovitch, P.; Schapiro, M.B.; Rapoport, S.I. (National Institutes of Health, Bethesda, MD (USA))

1991-03-01

142

Bridging the gap: global disparity processing in the human visual cortex  

PubMed Central

The human stereoscopic system is remarkable in its ability to utilize widely separated features as references to support fine depth discrimination. In a search for possible neural substrates of this ability, we recorded high-density EEG and used a distributed inverse technique to estimate population-level disparity responses in five regions of interest (ROIs): V1, V3A, hMT+, V4, and lateral occipital complex (LOC). The stimulus was a central modulating disk surrounded by a correlated “reference” annulus presented in the fixation plane. We varied a gap separating the disk from the annulus parametrically from 0 to 5.5° as a test of long-range disparity integration. In the V1, LOC, and hMT+ ROIs, the responses with gaps >0.5° were equal to those obtained in a control condition where the surround was composed of uncorrelated noise (no reference). By contrast, in the V4 and V3A ROIs, responses with gaps as large as 5.5° were still significantly higher than the control. As a test of the spatial distribution of the disparity reference information, we manipulated the properties of the stimulus by placing noise between the center and the surround or throughout the surround. The V3A ROI was particularly sensitive to disparity noise between the center and annulus regions, suggesting an important contribution of disparity edge detectors in this ROI. PMID:22323636

McKee, Suzanne P.; Norcia, Anthony M.

2012-01-01

143

Facial expression recognition takes longer in the posterior superior temporal sulcus than in the occipital face area.  

PubMed

Neuroimaging studies have identified a face-selective region in the right posterior superior temporal sulcus (rpSTS) that responds more strongly during facial expression recognition tasks than during facial identity recognition tasks, but precisely when the rpSTS begins to causally contribute to expression recognition is unclear. The present study addressed this issue using transcranial magnetic stimulation (TMS). In Experiment 1, repetitive TMS delivered over the rpSTS of human participants, at a frequency of 10 Hz for 500 ms, selectively impaired a facial expression task but had no effect on a matched facial identity task. In Experiment 2, participants performed the expression task only while double-pulse TMS (dTMS) was delivered over the rpSTS or over the right occipital face area (rOFA), a face-selective region in lateral occipital cortex, at different latencies up to 210 ms after stimulus onset. Task performance was selectively impaired when dTMS was delivered over the rpSTS at 60-100 ms and 100-140 ms. dTMS delivered over the rOFA impaired task performance at 60-100 ms only. These results demonstrate that the rpSTS causally contributes to expression recognition and that it does so over a longer time-scale than the rOFA. This difference in the length of the TMS induced impairment between the rpSTS and the rOFA suggests that the neural computations that contribute to facial expression recognition in each region are functionally distinct. PMID:24990937

Pitcher, David

2014-07-01

144

Electrochemical Dissolved Oxygen Removal from Microfluidic Streams for LOC Sample Pretreatment.  

PubMed

Current water quality monitoring for heavy metal contaminants largely results in analytical snapshots at a particular time and place. Therefore, we have been interested in miniaturized and inexpensive sensors suitable for long-term, real-time monitoring of the drinking water distribution grid, industrial wastewater effluents, and even rivers and lakes. Among the biggest challenges for such sensors are the issues of in-field device calibration and sample pretreatment. Previously, we have demonstrated use of coulometric stripping analysis for calibration-free determination of copper and mercury. For more negatively reduced metals, O2 reduction interferes with stripping analysis; hence, most electroanalysis techniques rely on pretreatments to remove dissolved oxygen (DO). Current strategies for portable DO removal offer limited practicality, because of their complexity, and often cause inadvertent sample alterations. Therefore, we have designed an indirect in-line electrochemical DO removal device (EDOR), utilizing a silver cathode to reduce DO in a chamber that is fluidically isolated from the sample stream by an O2-permeable membrane. The resulting concentration gradient supports passive DO diffusion from the sample stream into the deoxygenation chamber. The DO levels in the sample stream were determined by cyclic voltammetry (CV) and amperometry at a custom thin-layer cell (TLC) detector. Results show removal of 98% of the DO in a test sample at flow rates approaching 50 ?L/min and power consumption as low as 165 mW h L(-1) at steady state. Besides our specific stripping application, this device is well-suited for LOC applications where miniaturized DO removal and/or regulation are desirable. PMID:25082792

Marei, Mohamed M; Roussel, Thomas J; Keynton, Robert S; Baldwin, Richard P

2014-09-01

145

Occipital diploic cranial fasciitis after radiotherapy for a cerebellar medulloblastoma.  

PubMed

Radiation-induced cranial fasciitis is a rare complication of radiotherapy, especially in an intradiploic location. The authors report such a case of cranial fasciitis in a 13-year-old girl previously subjected to cranial radiotherapy for a recurrent cerebellar medulloblastoma. The patient had undergone a gross-total removal of a medulloblastoma followed by no radiation therapy at the age of 10 years. The tumor recurred at the original site 2 years later, warranting a repeat operation with a gross-total tumor removal and subsequent radiation therapy. The follow-up MRI sequence demonstrated no abnormal appearance for 1 year, until a new enhancing mass was found within the occipital bone adjacent to the prior bone window. Following its resection, the new lesion was histologically identified as cranial fasciitis. Differential diagnosis of a well-circumscribed bone lesion should include cranial fasciitis, especially in young children with radiotherapy for a previous intracranial malignancy. Radiotherapy should be considered among the inciting factors in the development of cranial fasciitis. The osteolytic lesions of cranial fasciitis, although nontumoral and self-limited in duration, should be eligible candidates for early, total resection to avoid potential intracranial expansion. PMID:24116980

Wu, Bo; Zhu, Hong; Liu, Weidong; Chen, Longyi

2013-12-01

146

Occipital Condyle Fracture With Isolated Unilateral Hypoglossal Nerve Palsy  

PubMed Central

Occipital condyle fractures (OCFs) with selective involvement of the hypoglossal canal are rare. OCFs usually occur after major trauma and combine multiple fractures. We describe a 38-year-old man who presented with neck pain and a tongue deviation to the right side after a traffic accident. Severe limitations were detected during active and passive range of neck motion in all directions. A physical examination revealed a normal gag reflex and normal mobility of the palate, larynx, and shoulder girdle. He had normal taste and general sensation in his tongue. However, he presented with a tongue deviation to the right side on protrusion. A videofluoroscopic swallowing study revealed piecemeal deglutition due to decreased tongue mobility but no aspiration of food. Plain X-ray film findings were negative, but a computed tomography study with coronal reconstruction demonstrated a right OCF involving the hypoglossal canal. An electrodiagnostic study revealed evidence of right hypoglossal nerve palsy. We report a rare case of isolated hypoglossal nerve palsy caused by an OCF. PMID:25379499

Yoon, Jin Won; Lim, Oh Kyung; Park, Ki Deok

2014-01-01

147

Occipital condyle fracture with isolated unilateral hypoglossal nerve palsy.  

PubMed

Occipital condyle fractures (OCFs) with selective involvement of the hypoglossal canal are rare. OCFs usually occur after major trauma and combine multiple fractures. We describe a 38-year-old man who presented with neck pain and a tongue deviation to the right side after a traffic accident. Severe limitations were detected during active and passive range of neck motion in all directions. A physical examination revealed a normal gag reflex and normal mobility of the palate, larynx, and shoulder girdle. He had normal taste and general sensation in his tongue. However, he presented with a tongue deviation to the right side on protrusion. A videofluoroscopic swallowing study revealed piecemeal deglutition due to decreased tongue mobility but no aspiration of food. Plain X-ray film findings were negative, but a computed tomography study with coronal reconstruction demonstrated a right OCF involving the hypoglossal canal. An electrodiagnostic study revealed evidence of right hypoglossal nerve palsy. We report a rare case of isolated hypoglossal nerve palsy caused by an OCF. PMID:25379499

Yoon, Jin Won; Lim, Oh Kyung; Park, Ki Deok; Lee, Ju Kang

2014-10-01

148

Osteomyelitis of the atlanto-occipital region as a sequela to a pharyngeal stick injury.  

PubMed

An eight-year-old female Belgian shepherd dog was referred for investigation of chronic neck pain. The dog had sustained a pharyngeal injury 12 weeks previously while catching a stick. Radiographs of the cervical spine revealed signs consistent with a septic arthritis of the atlanto-occipital joint and osteomyelitis of both occipital condyles and the atlas. A foreign body was identified ultrasonographically in the retropharyngeal soft tissues, and a stick was surgically removed from a site ventral to the right side of the atlanto-occipital joint. The signs of neck pain started to resolve within a week of surgery. PMID:10516953

Pratt, J N; Munro, E A; Kirby, B M

1999-09-01

149

Reading impairment in an adolescent with temporo-occipital epilepsy. Pre- and post-surgical evaluation.  

PubMed

We present a 16 year-old right-handed case who underwent a left temporo-occipital resection to treat intractable epilepsy. Pre- and post-surgical evaluations showed an average intellectual quotient, preserved abilities in language and visuo-spatial functions and increased reading and spelling deficits (difficulties with irregular words, homophones and phonologically valid spelling errors of irregularly spelled words, associated with preserved performances in non-words). This pattern of characteristic lexical route deficits highlights the major role of the temporo-occipital areas in reading acquisition. We discussed the consequences of temporo-occipital dysfunction on reading. PMID:23116198

Grosmaitre, Catherine; Auclair, Laurent; Dorfmuller, Georg; Leunen, Dorothée; Delalande, Olivier; Folhen, Martine; Bulteau, Christine; Jambaqué, Isabelle

2014-01-01

150

iLoc-Gpos: a multi-layer classifier for predicting the subcellular localization of singleplex and multiplex Gram-positive bacterial proteins.  

PubMed

By introducing the "multi-layer scale", as well as hybridizing the information of gene ontology and the sequential evolution information, a novel predictor, called iLoc-Gpos, has been developed for predicting the subcellular localization of Gram positive bacterial proteins with both single-location and multiple-location sites. For facilitating comparison, the same stringent benchmark dataset used to estimate the accuracy of Gpos-mPLoc was adopted to demonstrate the power of iLoc-Gpos. The dataset contains 519 Gram-positive bacterial proteins classified into the following four subcellular locations: (1) cell membrane, (2) cell wall, (3) cytoplasm, and (4) extracell; none of proteins included has ?25% pairwise sequence identity to any other in a same subset (subcellular location). The overall success rate by jackknife test on such a stringent benchmark dataset by iLoc-Gpos was over 93%, which is about 11% higher than that by GposmPLoc. As a user-friendly web-server, iLoc-Gpos is freely accessible to the public at http://icpr.jci.edu.cn/bioinfo/iLoc- Gpos or http://www.jci-bioinfo.cn/iLoc-Gpos. Meanwhile, a step-by-step guide is provided on how to use the web-server to get the desired results. Furthermore, for the user ? s convenience, the iLoc-Gpos web-server also has the function to accept the batch job submission, which is not available in the existing version of Gpos-mPLoc web-server. PMID:21919865

Wu, Zhi-Cheng; Xiao, Xuan; Chou, Kuo-Chen

2012-01-01

151

Comparison of the relative occipital bone volume between Cavalier King Charles spaniels with and without syringohydromyelia and French bulldogs.  

PubMed

Our aim was to determine the relative volume of the occipital bone of Cavalier King Charles spaniels with and without syringohydromyelia and normal French bulldogs to reappraise the role of a possible insufficiency of the paraxial mesoderm in the pathogenesis of the caudal occipital malformation syndrome. Analysis of the occipital bone volume of 43 dogs based on computed tomography datasets was performed. Volume was determined by means of three-dimensional models. Using manual segmentation of the occipital bone in sagittal, transverse, and dorsal images, the volume of the occipital bone and the rest of the skull was calculated. The absolute occipital bone volume was put in relation to the total skull volume, the occipital bone index. For the Cavalier King Charles spaniels without syringomyelia, the median occipital bone index was 0.0681; for Cavalier King Charles spaniels with syringomyelia, it was 0.0646 and for French bulldogs, it was 0.0676. There was no global difference of the occipital bone index between examined groups (P = 0.4331). A reduced volume of the occipital bone was not found in Cavalier King Charles spaniels in general in comparison to French bulldogs, or in Cavalier King Charles spaniels with syringomyelia compared to Cavalier King Charles spaniels without syringomyelia. These results do not support occipital hypoplasia as a cause for syringomyelia development, challenging the paraxial mesoderm insufficiency theory. This also suggests that the term Chiari-like malformation, a term derived from human studies, is not appropriate in the Cavalier King Charles spaniel. PMID:22702890

Schmidt, M J; Kramer, M; Ondreka, N

2012-01-01

152

INTERNATIONAL CONFERENCE ON SEMICONDUCTOR INJECTION LASERS SELCO-87: Far-field pattern of transverse modes in LOC structures  

NASA Astrophysics Data System (ADS)

An investigation was made of the emission from GaAlAs large-optical-cavity (LOC) laser heterostructures with an active layer more than 2 ?m thick. The far-field radiation pattern, representing a superposition of the fundamental and several higher-order transverse modes, had a central maximum. The gain, mirror losses, near- and far-field patterns of each propagation mode, as well as mode competition were analyzed on the basis of a simple model. The far-field pattern of single modes was determined by selecting separate spectral intervals from the total emission spectrum of the laser.

Petrescu-Prahova, I. B.; Lazanu, S.; Lep?a, M.; Mihailovici, P.

1988-11-01

153

Visual sensory-motor gating by serotonin activation in the medial prefrontal and occipital, but not in the rhinal, cortices in rats.  

PubMed

A behavioral reaction to sensory stimulation is a basic mechanism which is pivotal to many complex behavioral responses. In previous studies we found that visual stimulation induces a selective serotonergic and dopaminergic activation in the occipital (OccC), but not temporal (TempC) cortex in freely moving rats. In a behavioral study in rats we demonstrate now that visual stimulation (0, 8, 22, 82, 155 or 440 lux) activates behavioral activity in an intensity-dependent manner. Behavior activating visual stimulation with 82 lux, but not 22 lux or 82 dB white noise, increased extracellular serotonin (5-HT), but not dopamine (DA), in the medial prefrontal cortex (mPFC) in freely moving animals measured by in vivo microdialysis. There was no effect on 5-HT or DA in the entorhinal and perirhinal cortex. Visual stimulation with 82 lux increased extracellular 5-HT in the mPFC and OccC also in anesthetized animals, but had no effect in the TempC. Auditory stimulation reduced 5-HT in the TempC, but had no effect in the mPFC or OccC. Neither visual nor auditory stimulation had a significant effect on DA in all three cortical areas. We conclude that visual stimulation induces behavioral activation by increasing 5-HT activity in the mPFC and OccC. PMID:18378406

Pum, M E; Huston, J P; De Souza Silva, M A; Müller, C P

2008-05-01

154

Connections of the retrosplenial granular b cortex in the rat.  

PubMed

Although the retrosplenial granular b cortex (Rgb) is situated in a critical position between the hippocampal formation and the neocortex, surprisingly few studies have examined its connections carefully. The present experiments use both anterograde and retrograde tracing techniques to characterize the connections of Rgb. The main cortical projections from Rgb are to the caudal part of the anterior cingulate cortex, area 18b, retrosplenial granular a cortex (Rga), and postsubiculum, and less dense terminal fields are present in the prelimbic and caudal occipital cortices. The major subcortical projections are to the anterior thalamic nuclei and the rostral pontine nuclei, and very small terminal fields are present in the caudal dorsomedial part of the striatum, the reuniens and reticular nuclei of the thalamus, and the mammillary bodies. Contralaterally, Rgb primarily projects to itself, i.e., homotypically, and more sparsely projects to Rga and postsubiculum. In general, the axons from Rgb terminate ipsilaterally in cortical layers I and III-V and contralaterally in layer V, with a smaller number of terminals in layers I and VI. Thalamic projections from Rgb target the anteroventral and laterodorsal nuclei of the thalamus, with only a few axons terminating in the anterodorsal nucleus, the reticular nucleus, and the nucleus reuniens of the thalamus. Rgb is innervated by the anterior cingulate cortex, precentral agranular cortex, cortical area 18b, dorsal subiculum, and postsubiculum. Subcortical projections to Rgb originate mainly in the claustrum, the horizontal limb of the diagonal band of Broca, and the anterior thalamic nuclei. These data demonstrate that, in the rat, Rgb is a major nodal point for the integration and subsequent distribution of information to and from the hippocampal formation, the midline limbic and visual cortices, and the thalamus. Thus, similarly to the entorhinal cortex, Rgb in the rat is a prominent gateway for information exchange between the hippocampal formation and other limbic areas of the brain. PMID:12820159

Van Groen, Thomas; Wyss, J Michael

2003-08-25

155

Visuospatial Consciousness and Parieto-occipital Areas: A High-resolution EEG Study  

Microsoft Academic Search

Conscious and unconscious visuo-spatial processes are mainly related to parieto-occipital cortical activation. In this study, the working hypothesis was that a specific pattern of parieto-occipital activation is induced by conscious, as opposed to unconscious, visuo-spatial processes. Electroencephalographic data (128 chan- nels) were recorded in 12 normal adults during a visuo-spatial task. A cue stimulus appeared on the right or the

Claudio Babiloni; Fabrizio Vecchio; Maurizio Miriello; Gian Luca Romani; Paolo Maria Rossini

2005-01-01

156

Contraversive seizures in occipital epilepsy: case report and review of the literature.  

PubMed

We studied a man with repeated seizures characterized by deviation of the head and eyes to the left. A right occipital focus was demonstrated in the EEG. Adversion is usually associated with frontal or temporal lobe seizures; the direction of adversion is equally likely to be ipsilateral as contralateral to the ictal focus. In all reports of occipital epilepsy, the ictal focus has been contralateral to the direction of head turning. PMID:3080697

Rosenbaum, D H; Siegel, M; Rowan, A J

1986-02-01

157

Elevated occipital ?-amyloid deposition is associated with widespread cognitive impairment in logopenic progressive aphasia  

PubMed Central

Background Most subjects with logopenic primary progressive aphasia (lvPPA) have beta-amyloid (A?) deposition on Pittsburgh Compound B PET (PiB-PET), usually affecting prefrontal and temporoparietal cortices, with less occipital involvement. Objectives To assess clinical and imaging features in lvPPA subjects with unusual topographic patterns of A? deposition with highest uptake in occipital lobe. Methods Thirty-three lvPPA subjects with A? deposition on PiB-PET were included in this case-control study. Line-plots of regional PiB uptake were created, including frontal, temporal, parietal and occipital regions, for each subject. Subjects in which the line sloped downwards in occipital lobe (lvPPA-low), representing low uptake, were separated from those where the line sloped upwards in occipital lobe (lvPPA-high), representing unusually high occipital uptake compared to other regions. Clinical variables, atrophy on MRI, hypometabolism on F18-fluorodeoxyglucose PET, and presence and distribution of microbleeds and white matter hyperintensities (WMH) were assessed. Results Seventeen subjects (52%) were classified as lvPPA-high. Mean occipital PiB uptake in lvPPA-high was higher than all other regions, and higher than all regions in lvPPA-low. The lvPPA-high subjects performed more poorly on cognitive testing, including executive and visuospatial testing, but the two groups did not differ in aphasia severity. Proportion of microbleeds and WMH was higher in lvPPA-high than lvPPA-low. Parietal hypometabolism was greater in lvPPA-high than lvPPA-low. Conclusions Unusually high occipital A? deposition is associated with widespread cognitive impairment and different imaging findings in lvPPA. These findings help explain clinical heterogeneity in lvPPA, and suggest that A? influences severity of overall cognitive impairment but not aphasia. PMID:23946416

Whitwell, Jennifer L.; Lowe, Val J.; Duffy, Joseph R.; Strand, Edythe A.; Machulda, Mary M.; Kantarci, Kejal; Wille, Samantha M.; Senjem, Matthew L.; Murphy, Matthew C.; Gunter, Jeffrey L.; Jack, Clifford R.; Josephs, Keith A.

2014-01-01

158

Anatomical determination of a safe entry point for occipital condyle screw using three-dimensional landmarks  

Microsoft Academic Search

The occipital condyle (OC) is an important area in craniovertebral surgery, but neither its anatomical features nor the procedures\\u000a concerning the OC have been detailed yet. The morphological analysis of the structures were made in totally 704 sides of the\\u000a occipital bones of adult skulls by 3D-Doctor Demo version. The length and width of the OC were found to be

Mehmet Asim Ozer; Servet Celik; Figen Govsa; Mahmut Oguz Ulusoy

159

Three Cases with Visual Hallucinations following Combined Ocular and Occipital Damage  

PubMed Central

Charles Bonnet syndrome is an underrecognized disease that involves visual hallucinations in visually impaired patients. We present the cases of three patients who experienced complex visual hallucinations following various pathomechanisms. In two cases, diagnosis showed coexistence of occipital lobe damage with ocular damage, while in the third case it showed occipital lobe damage with retrobulbar optic neuritis. Theories of pathogenesis and the neuroanatomical basis of complex visual hallucinations are discussed and supported by literature review. PMID:24376461

Paradowski, Boguslaw; Kowalczyk, Edyta; Chojdak-Lukasiewicz, Justyna; Sluzewska-Niedzwiedz, Monika

2013-01-01

160

Transient facial nerve palsy after occipital nerve block: a case report.  

PubMed

Occipital nerve blocks are commonly performed to treat a variety of headache syndromes and are generally believed to be safe and well tolerated. We report the case of an otherwise healthy 24-year-old woman with left side-locked occipital, parietal, and temporal pain who was diagnosed with probable occipital neuralgia. She developed complete left facial nerve palsy within minutes of blockade of the left greater and lesser occipital nerves with a solution of bupivicaine and triamcinolone. Magnetic resonance imaging of the brain with gadolinium contrast showed no abnormalities, and symptoms had completely resolved 4-5 hours later. Unintended spread of the anesthetic solution along tissue planes seems the most likely explanation for this adverse event. An aberrant course of the facial nerve or connections between the facial and occipital nerves also might have played a role, along with the patient's prone position and the use of a relatively large injection volume of a potent anesthetic. Clinicians should be aware that temporary facial nerve palsy is a possible complication of occipital nerve block. PMID:24913733

Strauss, Lauren; Loder, Elizabeth; Rizzoli, Paul

2014-11-01

161

Neural Responses in Parietal and Occipital Areas in Response to Visual Events Are Modulated by Prior Multisensory Stimuli  

PubMed Central

The effect of multi-modal vs uni-modal prior stimuli on the subsequent processing of a simple flash stimulus was studied in the context of the audio-visual ‘flash-beep’ illusion, in which the number of flashes a person sees is influenced by accompanying beep stimuli. EEG recordings were made while combinations of simple visual and audio-visual stimuli were presented. The experiments found that the electric field strength related to a flash stimulus was stronger when it was preceded by a multi-modal flash/beep stimulus, compared to when it was preceded by another uni-modal flash stimulus. This difference was found to be significant in two distinct timeframes – an early timeframe, from 130–160 ms, and a late timeframe, from 300–320 ms. Source localisation analysis found that the increased activity in the early interval was localised to an area centred on the inferior and superior parietal lobes, whereas the later increase was associated with stronger activity in an area centred on primary and secondary visual cortex, in the occipital lobe. The results suggest that processing of a visual stimulus can be affected by the presence of an immediately prior multisensory event. Relatively long-lasting interactions generated by the initial auditory and visual stimuli altered the processing of a subsequent visual stimulus. PMID:24391939

Innes-Brown, Hamish; Barutchu, Ayla; Crewther, David P.

2013-01-01

162

Allocentric versus egocentric representation of remembered reach targets in human cortex.  

PubMed

The location of a remembered reach target can be encoded in egocentric and/or allocentric reference frames. Cortical mechanisms for egocentric reach are relatively well described, but the corresponding allocentric representations are essentially unknown. Here, we used an event-related fMRI design to distinguish human brain areas involved in these two types of representation. Our paradigm consisted of three tasks with identical stimulus display but different instructions: egocentric reach (remember absolute target location), allocentric reach (remember target location relative to a visual landmark), and a nonspatial control, color report (report color of target). During the delay phase (when only target location was specified), the egocentric and allocentric tasks elicited widely overlapping regions of cortical activity (relative to the control), but with higher activation in parietofrontal cortex for egocentric task and higher activation in early visual cortex for allocentric tasks. In addition, egocentric directional selectivity (target relative to gaze) was observed in the superior occipital gyrus and the inferior occipital gyrus, whereas allocentric directional selectivity (target relative to a visual landmark) was observed in the inferior temporal gyrus and inferior occipital gyrus. During the response phase (after movement direction had been specified either by reappearance of the visual landmark or a pro-/anti-reach instruction), the parietofrontal network resumed egocentric directional selectivity, showing higher activation for contralateral than ipsilateral reaches. These results show that allocentric and egocentric reach mechanisms use partially overlapping but different cortical substrates and that directional specification is different for target memory versus reach response. PMID:25209289

Chen, Ying; Monaco, Simona; Byrne, Patrick; Yan, Xiaogang; Henriques, Denise Y P; Crawford, J Douglas

2014-09-10

163

Hemodynamic Response to Featural Changes in the Occipital and Inferior Temporal Cortex in Infants: A Preliminary Methodological Exploration  

ERIC Educational Resources Information Center

Over the past 30 years researchers have learned a great deal about the development of object processing in infancy. In contrast, little is understood about the neural mechanisms that underlie this capacity, in large part because there are few techniques available to measure brain functioning in human infants. The present research examined the…

Wilcox, Teresa; Bortfeld, Heather; Woods, Rebecca; Wruck, Eric; Boas, David A.

2008-01-01

164

Abnormal visual field maps in human cortex: a mini-review and a case report.  

PubMed

Human visual cortex contains maps of the visual field. Much research has been dedicated to answering whether and when these visual field maps change if critical components of the visual circuitry are damaged. Here, we first provide a focused mini-review of the functional magnetic resonance imaging (fMRI) studies that have evaluated the human cortical visual field maps in the face of retinal lesions, brain injury, and atypical retinocortical projections. We find that there is a fair body of research that has found abnormal fMRI activity, but also that this abnormal activity does not necessarily stem from cortical remapping. The abnormal fMRI activity can often be explained in terms of task effects and/or the uncovering of normally hidden system dynamics. We then present the case of a 16-year-old patient who lost the entire left cerebral hemisphere at age three for treatment of chronic focal encephalitis (Rasmussen syndrome) and intractable epilepsy. Using an fMRI retinotopic mapping procedure and population receptive field (pRF) modeling, we found that (1) despite the long period since the hemispherectomy, the retinotopic organization of early visual cortex remained unaffected by the removal of an entire cerebral hemisphere, and (2) the intact lateral occipital cortex contained an exceptionally large representation of the center of the visual field. The same method also indicates that the neuronal receptive fields in these lateral occipital brain regions are extraordinarily small. These features are clearly abnormal, but again they do not necessarily stem from cortical remapping. For example, the abnormal features can also be explained by the notion that the hemispherectomy took place during a critical period in the development of the lateral occipital cortex and therefore arrested its normal development. Thus, caution should be exercised when interpreting abnormal fMRI activity as a marker of cortical remapping; there are often other explanations. PMID:23347557

Haak, Koen V; Langers, Dave R M; Renken, Remco; van Dijk, Pim; Borgstein, Johannes; Cornelissen, Frans W

2014-07-01

165

A real-world size organization of object responses in occipito-temporal cortex  

PubMed Central

SUMMARY While there are selective regions of occipito-temporal cortex that respond to faces, letters, and bodies, the large-scale neural organization of most object categories remains unknown. Here we find that object representations can be differentiated along the ventral temporal cortex by their real-world size. In a functional neuroimaging experiment, observers were shown pictures of big and small real-world objects (e.g. table, bathtub; paperclip, cup), presented at the same retinal size. We observed a consistent medial-to-lateral organization of big and small object preferences in the ventral temporal cortex, mirrored along the lateral surface. Regions in the lateral-occipital, infero-temporal, and parahippocampal cortices showed strong peaks of differential real-world size selectivity, and maintained these preferences over changes in retinal size and in mental imagery. These data demonstrate that the real-world size of objects can provide insight into the spatial topography of object representation. PMID:22726840

Konkle, Talia; Oliva, Aude

2012-01-01

166

Forensic age estimation by spheno-occipital synchondrosis fusion degree: computed tomography analysis.  

PubMed

The analysis of ossification points plays a considerable role in forensic age estimation. Although traditional methods are still in use, researchers are working on different age estimation procedures especially within the development of radiologic methods. One of these methods is to define spheno-occipital synchondrosis fusion degree. Spheno-occipital synchondrosis, an important growth point on cranial base, provides noteworthy information about age estimation through its late stage ossification nature. This study aimed to investigate spheno-occipital synchondrosis fusion degree for age estimation in the Turkish population. In our study, 1-mm-sectioned computed tomography images of 638 (399 men and 139 women) subjects within the age of 10 to 25 years were retrospectively examined. It is stated in our study that spheno-occipital syncondrosis fusion begins superiorly and progresses inferiorly until it is completed. Spheno-occipital syncondrosis is known to be totally open at the mean (SD) age of 11.5 (1.5) years in men and 10.7 (0.8) years in women. In addition, fusion degree is known to be increased with age. Fusion starts approximately 2 years earlier in women than in men, and the process of fusion completes at the age of 17 years in both sexes. An analysis of fusion degree between sex groups showed significance at the age of 11 to 15 years, and Spearman rank correlations indicate a significant positive relationship between age and degree of spheno-occipital fusion (P < 0.001; men, ? = 0.714; women, ? = 0.698). Consequently, 5-staged analysis of spheno-occipital synchondrosis fusion degree in use with 1-mm computed tomography images will be helpful for age estimation between 11 and 17 years. PMID:25006899

Can, Ismail Ozgur; Ekizoglu, Oguzhan; Hocaoglu, Elif; Inci, Ercan; Sayin, Ibrahim; Kaya, Kamil Hakan

2014-07-01

167

iLoc-Virus: a multi-label learning classifier for identifying the subcellular localization of virus proteins with both single and multiple sites.  

PubMed

In the last two decades or so, although many computational methods were developed for predicting the subcellular locations of proteins according to their sequence information, it is still remains as a challenging problem, particularly when the system concerned contains both single- and multiple-location proteins. Also, among the existing methods, very few were developed specialized for dealing with viral proteins, those generated by viruses. Actually, knowledge of the subcellular localization of viral proteins in a host cell or virus-infected cell is very important because it is closely related to their destructive tendencies and consequences. In this paper, by introducing the "multi-label scale" and by hybridizing the gene ontology information with the sequential evolution information, a predictor called iLoc-Virus is developed. It can be utilized to identify viral proteins among the following six locations: (1) viral capsid, (2) host cell membrane, (3) host endoplasmic reticulum, (4) host cytoplasm, (5) host nucleus, and (6) secreted. The iLoc-Virus predictor not only can more accurately predict the location sites of viral proteins in a host cell, but also have the capacity to deal with virus proteins having more than one location. As a user-friendly web-server, iLoc-Virus is freely accessible to the public at http://icpr.jci.edu.cn/bioinfo/iLoc-Virus. Meanwhile, a step-by-step guide is provided on how to use the web-server to get the desired results. Furthermore, for the user's convenience, the iLoc-Virus web-server also has the function to accept the batch job submission. It is anticipated that iLoc-Virus may become a useful high throughput tool for both basic research and drug development. PMID:21684290

Xiao, Xuan; Wu, Zhi-Cheng; Chou, Kuo-Chen

2011-09-01

168

Occipital afferent activation of second order neurons in the trigeminocervical complex in rat.  

PubMed

Stimulation of the greater occipital nerve produces excitation of second order neurons in the trigeminocervical complex. Given that neck pain is very common in primary headache disorders, this convergent excitation may play a role in pain referral from cervical structures. While previous studies have demonstrated a physiological model for this convergence, this study sought an anatomical approach to examine the distribution of second order neurons in the trigeminocervical complex receiving greater occipital nerve input. In addition, the role of glutamatergic NMDA receptor activation within the trigeminocervical complex in response to cervical afferents was studied. Noxious stimulation of the occipital muscle in rat using mustard oil and mineral oil produced significantly altered Fos expression in the trigeminocervical complex compared with the surgical control (H(4)=31.3, P<0.001, Kruskal-Wallis). Baseline expression was 11 (median, range 4, 17) fos positive cells in the trigeminocervical complex, occipital muscle treated with mustard oil produced 23 (17, 33) and mineral oil a smaller effect of 19 (15, 25) fos positive cells, respectively (P=0.046). The effects of both mustard and mineral oil were reversed by the NMDA-receptor antagonist MK801. This study introduces a model for examining trigeminocervical complex activity after occipital afferent stimulation in the rat that has good anatomical resolution and demonstrates involvement of glutamatergic NMDA receptors at this important synapse. PMID:16730124

Le Doaré, K; Akerman, S; Holland, P R; Lasalandra, M P; Bergerot, A; Classey, J D; Knight, Y E; Goadsby, P J

2006-07-31

169

When the left brain is not right the right brain may be left: report of personal experience of occipital hemianopia  

PubMed Central

OBJECTIVES—To make a personal report of a hemianopia due to an occipital infarct, sustained by a professor of neurology.?METHODS—Verbatim observation of neurological phenomena recorded during the acute illness.?RESULTS—Hemianopia, visual hallucinations, and non-occipital deficits without extraoccipital lesions on MRI, are described and discussed.?CONCLUSIONS—Hemianopia, due to an occipital infarct, without alexia, is not a disability which precludes a normal professional career. Neurorehabilitation has not been necessary.?? PMID:10406983

Cole, M.

1999-01-01

170

Thrombosed traumatic aneurysm of the occipital artery: a case report and review of the literature  

PubMed Central

Introduction Occipital artery aneurysms are very rare vascular lesions. Most cases reported in the literature have been post-traumatic pseudoaneurysms of the occipital artery. Case presentation We report the case of a 14-year-old Caucasian boy presented with a painless non-pulsatile scalp mass that developed rapidly after minor blunt head trauma. The scalp mass was excised six months after the trauma. A pathologic diagnosis of a thrombosed true aneurysm was made. Our patient has had no recurrence of the mass at 15?months follow-up. Conclusions We present a case of a true aneurysm of the occipital artery following minor head trauma. We review the literature for similar cases and discuss the difficulty of establishing a diagnosis prior to surgical intervention. PMID:22804804

2012-01-01

171

Occipital (V6) and parietal (V6A) areas in the anterior wall of the parieto-occipital sulcus of the macaque: a cytoarchitectonic study  

Microsoft Academic Search

The anterior wall of the parieto-occipital sulcus (POs) of the macaque monkey, classically considered as part of Brodmann's area 19, contains two functionally distinct areas: a ventral, purely visual area, V6, and a dorsal area, V6A, containing visual neurons and neurons related to the control of arm movements. The aim of this study was to establish whether areas V6 and

Giuseppe Luppino; Suliann Ben Hamed; Michela Gamberini; Massimo Matelli; Claudio Galletti

2005-01-01

172

Auditory cortexAuditory cortex Cerebral StructuresCerebral Structures  

E-print Network

SpainSpain #12;· Auditory cortexAuditory cortex #12;Cerebral StructuresCerebral Structures Sup. Temp. gyrus Supra marginal gyrusSupra marginal gyrus Temp. Polep #12;Aud. cortexMGB Brainstem & cerebral auditory tracts Int. capsule, sub lent. Inferior colliculus Dorsal coch. nuc. Ventral coch nuc Lat

Oliver, Douglas L.

173

Endovascular treatment of a pial arteriovenous fistula with occipital remodeling secondary to giant torcular dilation.  

PubMed

Intracranial arteriovenous fistulas are vascular malformations in which clinical suspicion and prompt diagnosis, with a subsequent appropriate therapeutic approach, are crucial to avoid the development of irreversible neurological damage or even patient death because these lesions can be associated with heavy bleeding and high mortality rates. The authors present the case of a direct pial arteriovenous fistula in an infant and its unusual presentation as a large occipital protuberance with hard consistency and an audible murmur that produced bone remodeling. The patient was successfully treated by endovascular therapy, with complete regression of the occipital protuberance during follow-up. PMID:21633103

Aguilar, Marta; González, Alejandro; López, Antonio; Gutiérrez, Isabel; Durand, Fernando; Mayol, Antonio

2011-08-01

174

Giant occipital meningocele in an 8-year-old child with Dandy–Walker malformation  

Microsoft Academic Search

Introduction  The possibility of an association between Dandy–Walker malformation and occipital meningocele is well-known. However, just\\u000a an overall number of about 40 cases have been previously reported. Giant occipital meningocele has been described only in\\u000a three newborns. Incidence, pathology, clinical presentation, and proper management of this association are still poorly defined.\\u000a \\u000a \\u000a \\u000a \\u000a Report of the case  An 8-year-old boy with Dandy–Walker malformation and

Giuseppe Talamonti; Marco Picano; Alberto Debernardi; Moreno Bolzon; Mario Teruzzi; Giuseppe D’Aliberti

2011-01-01

175

Nummular headache in a patient with ipsilateral occipital neuralgia--a case report.  

PubMed

Nummular headache (NH) is a rarely recognized primary headache, the diagnostic criteria of which are contained in the appendix to the 2nd edition of the International Classification of Headache Disorders (code A13.7.1). We present the case of a 61-year-old female who suffers, regardless of NH, from right-sided occipital neuralgia. The applied treatment - gabapentin and mianserin - had no effect. Injection of bupivacaine twice to the right occipital region resulted in neuralgia resolution up to three months, with no effect on NH. This confirms the independence of two above mentioned head pain conditions. PMID:24821641

Iwanowski, Piotr; Kozubski, Wojciech; Losy, Jacek

2014-01-01

176

Benign occipital unicameral bone cyst causing lower cranial nerve palsies complicated by iophendylate arachnoiditis  

PubMed Central

A 20 year old girl presented with a history of neck and occipital pain for six weeks, which was found to be due to a unicameral bone cyst of the left occipital condylar region. The differential diagnosis of bone cysts in the skull is discussed. Six months after the operation, the patient again presented with backache due to adhesive arachnoiditis. The latter was believed to have arisen as a result of a combination of spinal infective meningitis and intrathecal ethyl iodophenyl undecylate (iophendylate, Myodil, Pantopaque). The nature of meningeal reactions to iophendylate and the part played by intrathecal corticosteroids in relieving the arachnoiditis in the present case are discussed. Images

Bradley, W. G.; Kalbag, R. M.; Ramani, P. S.; Tomlinson, B. E.

1974-01-01

177

Fatal Airbag-Mediated Atlanto-Occipital Dislocation in a Child  

PubMed Central

An atlanto-occipital dislocation is a rare airbag-induced injury in trauma patients. We report a case of an atlanto-occipital dislocation in a 6-year-old patient who was an unrestrained passenger in the front seat of a vehicle involved in a low-speed motor vehicle accident. This case illustrates the fatal threat of airbag deployment to the child passenger travelling in the vehicle front seat even in a low-speed collision, and supports the recommendation that children under 12 years of age travelling in vehicles with dual airbag systems should be seated in the back. PMID:22135564

Hassan, Radhiana; Mohd Yusof, Mubarak; Kamarudin, Norie Azilah

2010-01-01

178

PAPER www.rsc.org/loc | Lab on a Chip Programmable assembly of a metabolic pathway enzyme in a pre-packaged  

E-print Network

PAPER www.rsc.org/loc | Lab on a Chip Programmable assembly of a metabolic pathway enzyme in a pre report a biofunctionalization strategy for the assembly of catalytically active enzymes within and temporally defined sites. The enzyme of a bacterial metabolic pathway, S-adenosylhomocysteine nucleosidase

Rubloff, Gary W.

179

COMMUNICATION www.rsc.org/loc | Lab on a Chip Sub-cellular precision on-chip small-animal immobilization, multi-photon  

E-print Network

COMMUNICATION www.rsc.org/loc | Lab on a Chip Sub-cellular precision on-chip small-animal on the web 2nd April 2008 DOI: 10.1039/b804808h Techniques for stable, rapid and repeatable small-animal immobilization are necessary for high-throughput in vivo genetic/drug screens using cellular and sub

Yanik, Mehmet Fatih

180

A case of early-onset benign occipital seizure susceptibility syndrome: decreased cerebral blood flow in the occipital region detected by interictal single photon emission computed tomography, corresponding to the epileptogenic focus  

Microsoft Academic Search

Early-onset benign childhood occipital seizure susceptibility syndrome (EBOSS) recently described by Panayiotopoulos, is an early-onset variant of benign childhood epilepsy with occipital paroxysms. EBOSS is characterized by partial seizures that are predominantly manifested at night and associated with deviation of the eyes, vomiting and impairment of consciousness, but without ictal visual symptoms or postictal headache. The clinical features of our

Masanori Sakagami; Yukihiro Takahashi; Hiroaki Matsuoka; Tohru Hoshida; Kazushi Izaki; Sadao Nouka; Akira Yoshioka

2001-01-01

181

iLoc-Plant: a multi-label classifier for predicting the subcellular localization of plant proteins with both single and multiple sites.  

PubMed

Predicting protein subcellular localization is a challenging problem, particularly when query proteins may simultaneously exist at, or move between, two or more different subcellular location sites. Most of the existing methods can only be used to deal with the single-location proteins. Actually, multiple-location proteins should not be ignored because they usually bear some special functions worthy of our notice. By introducing the "multi-labeled learning" approach, a new predictor, called iLoc-Plant, has been developed that can be used to deal with the systems containing both single- and multiple-location plant proteins. As a demonstration, the jackknife cross-validation was performed with iLoc-Plant on a benchmark dataset of plant proteins classified into the following 12 location sites: (1) cell membrane, (2) cell wall, (3) chloroplast, (4) cytoplasm, (5) endoplasmic reticulum, (6) extracellular, (7) Golgi apparatus, (8) mitochondrion, (9) nucleus, (10) peroxisome, (11) plastid, and (12) vacuole, where some proteins belong to two or three locations but none has ? 25% pairwise sequence identity to any other in a same subset. The overall success rate thus obtained by iLoc-Plant was 71%, which is remarkably higher than those achieved by any existing predictors that also have the capacity to deal with such a stringent and complicated plant protein system. As a user-friendly web-server, iLoc-Plant is freely accessible to the public at the web-site or . Moreover, for the convenience of the vast majority of experimental scientists, a step-by-step guide is provided on how to use the web-server to get the desired results without the need to follow the complicated mathematic equations presented in this paper for its integrity. It is anticipated that iLoc-Plant may become a useful bioinformatics tool for Molecular Cell Biology, Proteomics, Systems Biology, and Drug Development. PMID:21984117

Wu, Zhi-Cheng; Xiao, Xuan; Chou, Kuo-Chen

2011-12-01

182

Supply of the Unilateral Circulation of the Brain by an Occipital Artery AnastomosisA Case Report  

Microsoft Academic Search

The author presents a case of occlusion of the right internal carotid artery in which the vertebral artery, the basilar artery and the entire right-sided anterior and posterior circulations were supplied by the right external carotid artery by way of an occipital-vertebral artery anastomosis. In this case, the usually small muscular branches of the occipital artery developed into collaterals capable

Andrei I. Holodny

2005-01-01

183

Evidence for metaplasticity in the human visual cortex.  

PubMed

The threshold and direction of excitability changes induced by low- and high-frequency repetitive transcranial magnetic stimulation (rTMS) in the primary motor cortex can be effectively reverted by a preceding session of transcranial direct current stimulation (tDCS), a phenomenon referred to as "metaplasticity". Here, we used a combined tDCS-rTMS protocol and visual evoked potentials (VEPs) in healthy subjects to provide direct electrophysiological evidence for metaplasticity in the human visual cortex. Specifically, we evaluated changes in VEPs at two different contrasts (90 and 20 %) before and at different time points after the application of anodal or cathodal tDCS to occipital cortex (i.e., priming), followed by an additional conditioning with low- or high-frequency rTMS. Anodal tDCS increased the amplitude of VEPs and this effect was paradoxically reverted by applying high-frequency (5 Hz), conventionally excitatory rTMS (p < 0.0001). Similarly, cathodal tDCS led to a decrease in VEPs amplitude, which was reverted by a subsequent application of conventionally inhibitory, 1 Hz rTMS (p < 0.0001). Similar changes were observed for both the N1 and P1 component of the VEP. There were no significant changes in resting motor threshold values (p > 0.5), confirming the spatial selectivity of our conditioning protocol. Our findings show that preconditioning primary visual area excitability with tDCS can modulate the direction and strength of plasticity induced by subsequent application of 1 or 5 Hz rTMS. These data indicate the presence of mechanisms of metaplasticity that keep synaptic strengths within a functional dynamic range in the human visual cortex. PMID:24162796

Bocci, Tommaso; Caleo, Matteo; Tognazzi, Silvia; Francini, Nikita; Briscese, Lucia; Maffei, Lamberto; Rossi, Simone; Priori, Alberto; Sartucci, Ferdinando

2014-03-01

184

Autism and visual agnosia in a child with right occipital lobectomy  

Microsoft Academic Search

OBJECTIVESAutistic disorder is a developmental handicap with an unknown neurological basis. Current neuropsychological models for autism suggest an abnormal construction of visual perceptual representation or a deficit in executive functions. These models predict cerebral lesions in the temporo-occipital or frontal regions of autistic patients. The present study aimed at studying the presence of symptoms of autism and visual agnosia in

I Jambaqué; L Mottron; G Ponsot; C Chiron

1998-01-01

185

Experienced Mindfulness Meditators Exhibit Higher Parietal-Occipital EEG Gamma Activity during NREM  

E-print Network

Experienced Mindfulness Meditators Exhibit Higher Parietal-Occipital EEG Gamma Activity during NREM meditation practice has gained increasing attention as a non-pharmacological intervention to provide health conditions. However, the effects of meditation training on brain activity still need to be fully

Wisconsin at Madison, University of

186

TGF-? mediated Msx2 expression controls occipital somites-derived caudal region of skull development  

Microsoft Academic Search

Craniofacial development involves cranial neural crest (CNC) and mesoderm-derived cells. TGF-? signaling plays a critical role in instructing CNC cells to form the craniofacial skeleton. However, it is not known how TGF-? signaling regulates the fate of mesoderm-derived cells during craniofacial development. In this study, we show that occipital somites contribute to the caudal region of mammalian skull development. Conditional

Ryoichi Hosokawa; Mark Urata; Jun Han; Armen Zehnaly; Pablo Bringas; Kazuaki Nonaka; Yang Chai

2007-01-01

187

Pax1 in the development of the cervico-occipital transitional zone  

Microsoft Academic Search

The Pax-1 gene has been found to play an important role in the development of the vertebral column. The cervico-occipital transitional zone is a specialized region of the vertebral column, and malformations of this region have frequently been described in humans. The exact embryonic border between head and trunk is a matter of controversy. In order to determine a possible

Jörg Wilting; Cecilia Ebensperger; Thomas S. Müller; Haruhiko Koseki; Johan Wallin; Bodo Christ

1995-01-01

188

Vasoactive intestinal polypeptide (VIP) containing cells in the developing rat occipital hemisphere  

Microsoft Academic Search

Numerous cells were observed to show intense vasoactive intestinal polypeptide (VIP) immunoreactivity from birth to postnatal day 8 in the subventricular zone of the rat occipital hemisphere. This cell population was markedly reduced by postnatal day 8, but isolated clusters of VIP cells persisted into adulthood. In addition, long, L-shaped VIP fibers were seen in the hemispheric wall up to

F. Hajós; K. Zilles; K. Gallatz

1990-01-01

189

Occipital Rhythmic Activity and Other Developmental Measures of Infants from High and Low Socioeconomic Groups.  

ERIC Educational Resources Information Center

This study sought to determine whether differences existed between infants from low socioeconomic status (SES) families and those from high SES families in the occipital rhythmic activity of the brain, as recorded in their electroencephalograms (EEGs), as well as in other developmental measures. Ten low SES white infants and 10 high SES white…

Inselberg, Rachel; And Others

190

Perinatal occipital lobe injury in children: analysis of twenty-one cases.  

PubMed

This study used magnetic resonance imaging to analyze causes and clinical courses of pediatric occipital lobe injury. Patients undergoing magnetic resonance imaging for suspected bilateral occipital lobe injury at our Neurodevelopmental Department between July 2007 and June 2011 were included. We evaluated magnetic resonance imaging characteristics, clinical courses, electroencephalogram monitoring, and Denver Development Screen Test scores. Twenty-one infants were examined. Of these, 10 had been born preterm. Thirteen patients demonstrated hypoglycemia. Perinatal period hypoglycemia comprised the most common cause (71.4%) of occipital brain injury. Visual abnormalities were evident in 18 patients. Seventeen (80.9%) patients manifested epilepsy. Infantile spasms were observed in 13 cases (76.5%). According to Denver Development Screen Test assessment, 17 patients demonstrated delayed motor development. Motor function and language improved in 10 patients after effective control of their seizures. Hypoglycemia constitutes the most common cause of occipital injury in infants. Visual impairment, startle episodes, infantile spasms, and motor developmental delay comprise the most common complications, whereas language function is usually spared. PMID:23127266

Wang, San-Mei; Yang, Chang-Shuan; Hou, Yu; Ma, Xiu-Wei; Feng, Zhi-Chun; Liao, Yu-Zhen

2012-12-01

191

CLOSURE TIME OF SPHENO-OCCIPITAL SUTURE IN THE MALE CADAVERS REFERRED TO LEGAL MEDICINE ORGANIZATION  

Microsoft Academic Search

The identity of dead is an essential part of post-mortem examination. The identification of unknown human remnants begins with the creation of an anthropological profile, which includes sex, biological age, stature and individualizing features. The estimation of age at death is based on the bodily biological changes that occur throughout life. Closure of spheno occipital synchondrosis is one of factors

M. Akhlaghi; B. Valizadeh

192

Dopamine D sub 2 receptors in the cerebral cortex: Distribution and pharmacological characterization with ( sup 3 H)raclopride  

SciTech Connect

An apparent involvement of dopamine in the regulation of cognitive functions and the recognition of a widespread dopaminergic innervation of the cortex have focused attention on the identity of cortical dopamine receptors. However, only the presence and distribution of dopamine D{sub 1} receptors in the cortex have been well documented. Comparable information on cortical D{sub 2} sites is lacking. The authors report here the results of binding studied in the cortex and neostriatum of rat and monkey using the D{sub 2} selective antagonist ({sup 3}H)raclopride. In both structures ({sup 3}H)raclopride bound in a sodium-dependent and saturable manner to a single population of sites with pharmacological profiles of dopamine D{sub 2} receptors. D{sub 2} sites were present in all regions of the cortex, although their density was much lower than in the neostriatum. The density of these sites in both monkey and, to a lesser extent, rat cortex displayed a rostral-caudal gradient with highest concentrations in the prefrontal and lowest concentrations in the occipital cortex, corresponding to dopamine levels in these areas. Thus, the present study established the presence and widespread distribution of dopamine D{sub 2} receptors in the cortex.

Lidow, M.S.; Goldman-Rakic, P.S.; Rakic, P.; Innis, R.B. (Yale Univ., New Haven, CT (USA))

1989-08-01

193

Atypical Retinotopic Organization of Visual Cortex in Patients with Central Brain Damage: Congenital and Adult Onset  

PubMed Central

It remains unclear to what extent retinotopic maps can undergo large-scale plasticity following damage to human visual cortex. The literature has predominately focused on retinotopic changes in patients with retinal pathologies or congenital brain malformations. Yet, damage to the adult visual cortex itself is common in cases such as stroke, tumor, or trauma. To address this issue, we used a unique database of fMRI vision maps in patients with adult-onset (n = 25) and congenital (n = 2) pathology of the visual cortex. We identified atypical retinotopic organization in three patients (two with adult-onset, and one with congenital pathology) consisting of an expanded ipsilateral field representation that was on average 3.2 times greater than healthy controls. The expanded representations were located at the vertical meridian borders between visual areas such as V1/V2. Additionally, two of the three patients had apparently an ectopic (topographically inconsistent) representation of the ipsilateral field within lateral occipital cortex that is normally associated with visual areas V3/V3A (and possibly other areas). Both adult-onset cases had direct damage to early visual cortex itself (rather than to the afferent drive only), resulting in a mostly nonfunctional hemisphere. The congenital case had severe cortical malformation of the visual cortex and was acallosal. Our results are consistent with a competitive model in which unilateral damage to visual cortex or disruption of the transcallosal connections removes interhemispheric suppression from retino-geniculate afferents in intact visual cortex that represent the vertical meridian and ipsilateral visual field. PMID:23926256

Mathis, Jedidiah; Ulmer, John L.; Mueller, Wade; Maciejewski, Mary J.; DeYoe, Edgar A.

2013-01-01

194

Brief communication: timing of spheno-occipital closure in modern Western Australians.  

PubMed

The spheno-occipital synchondrosis is a craniofacial growth centre between the occipital and sphenoid bones-its ossification persists into adolescence, which for the skeletal biologist, means it has potential application for estimating subadult age. Based on previous research the timing of spheno-occipital fusion is widely variable between and within populations, with reports of complete fusion in individuals as young as 11 years of age and nonfusion in adults. The aim of this study is, therefore, to examine this structure in a mixed sex sample of Western Australian individuals that developmentally span late childhood to adulthood. The objective is to develop statistically quantified age estimation standards based on scoring the degree of spheno-occipital fusion. The sample comprises multidetector computed tomography (MDCT) scans of 312 individuals (169 male; 143 female) between 5 and 25 years of age. Each MDCT scan is visualized in a standardized sagittal plane using three-dimensional oblique multiplanar reformatting. Fusion status is scored according to a four-stage system. Transition analysis is used to calculate age ranges for each defined stage and determine the mean age for transition between an unfused, fusing and fused status. The maximum likelihood estimates for the transition from open to fusing in the endocranial half is 14.44 years (male) and 11.42 years (female); transition from fusion in the ectocranial half to complete fusion is 16.16 years (male) and 13.62 years (female). This study affirms the potential value of assessing the degree of fusion in the spheno-occipital synchondrosis as an indicator of skeletal age. PMID:24318947

Franklin, Daniel; Flavel, Ambika

2014-01-01

195

Effects of Visual Cortex Activation on the Nociceptive Blink Reflex in Healthy Subjects  

PubMed Central

Bright light can cause excessive visual discomfort, referred to as photophobia. The precise mechanisms linking luminance to the trigeminal nociceptive system supposed to mediate this discomfort are not known. To address this issue in healthy human subjects we modulated differentially visual cortex activity by repetitive transcranial magnetic stimulation (rTMS) or flash light stimulation, and studied the effect on supraorbital pain thresholds and the nociceptive-specific blink reflex (nBR). Low frequency rTMS that inhibits the underlying cortex, significantly decreased pain thresholds, increased the 1st nBR block ipsi- and contralaterally and potentiated habituation contralaterally. After high frequency or sham rTMS over the visual cortex, and rMS over the right greater occipital nerve we found no significant change. By contrast, excitatory flash light stimulation increased pain thresholds, decreased the 1st nBR block of ipsi- and contralaterally and increased habituation contralaterally. Our data demonstrate in healthy subjects a functional relation between the visual cortex and the trigeminal nociceptive system, as assessed by the nociceptive blink reflex. The results argue in favour of a top-down inhibitory pathway from the visual areas to trigemino-cervical nociceptors. We postulate that in normal conditions this visuo-trigeminal inhibitory pathway may avoid disturbance of vision by too frequent blinking and that hypoactivity of the visual cortex for pathological reasons may promote headache and photophobia. PMID:24936654

Sava, Simona L.; de Pasqua, Victor; Magis, Delphine; Schoenen, Jean

2014-01-01

196

Vestibular function in the temporal and parietal cortex: distinct velocity and inertial processing pathways  

PubMed Central

A number of behavioral and neuroimaging studies have reported converging data in favor of a cortical network for vestibular function, distributed between the temporo-parietal cortex and the prefrontal cortex in the primate. In this review, we focus on the role of the cerebral cortex in visuo-vestibular integration including the motion sensitive temporo-occipital areas i.e., the middle superior temporal area (MST) and the parietal cortex. Indeed, these two neighboring cortical regions, though they both receive combined vestibular and visual information, have distinct implications in vestibular function. In sum, this review of the literature leads to the idea of two separate cortical vestibular sub-systems forming (1) a velocity pathway including MST and direct descending pathways on vestibular nuclei. As it receives well-defined visual and vestibular velocity signals, this pathway is likely involved in heading perception and rapid top-down regulation of eye/head coordination and (2) an inertial processing pathway involving the parietal cortex in connection with the subcortical vestibular nuclei complex responsible for velocity storage integration. This vestibular cortical pathway would be implicated in high-order multimodal integration and cognitive functions, including world space and self-referential processing. PMID:25071481

Ventre-Dominey, Jocelyne

2014-01-01

197

The auditory cortex  

Microsoft Academic Search

The division of the auditory cortex into various fields, functional aspects of these fields, and neuronal coding in the primary\\u000a auditory cortical field (AI) are reviewed with stress on features that may be common to mammals. On the basis of 14 topographies\\u000a and clustered distributions of neuronal response characteristics in the primary auditory cortical field, a hypothesis is developed\\u000a of

G. Ehret

1997-01-01

198

Multifactor Effects and Evidence of Potential Interaction between Complement Factor H Y402H and LOC387715 A69S in Age-Related Macular Degeneration  

PubMed Central

Background Variants in the complement cascade genes and the LOC387715/HTRA1, have been widely reported to associate with age-related macular degeneration (AMD), the most common cause of visual impairment in industrialized countries. Methods/Principal Findings We investigated the association between the LOC387715 A69S and complement component C3 R102G risk alleles in the Finnish case-control material and found a significant association with both variants (OR 2.98, p?=?3.75×10?9; non-AMD controls and OR 2.79, p?=?2.78×10?19, blood donor controls and OR 1.83, p?=?0.008; non-AMD controls and OR 1.39, p?=?0.039; blood donor controls), respectively. Previously, we have shown a strong association between complement factor H (CFH) Y402H and AMD in the Finnish population. A carrier of at least one risk allele in each of the three susceptibility loci (LOC387715, C3, CFH) had an 18-fold risk of AMD when compared to a non-carrier homozygote in all three loci. A tentative gene-gene interaction between the two major AMD-associated loci, LOC387715 and CFH, was found in this study using a multiplicative (logistic regression) model, a synergy index (departure-from-additivity model) and the mutual information method (MI), suggesting that a common causative pathway may exist for these genes. Smoking (ever vs. never) exerted an extra risk for AMD, but somewhat surprisingly, only in connection with other factors such as sex and the C3 genotype. Population attributable risks (PAR) for the CFH, LOC387715 and C3 variants were 58.2%, 51.4% and 5.8%, respectively, the summary PAR for the three variants being 65.4%. Conclusions/Significance Evidence for gene-gene interaction between two major AMD associated loci CFH and LOC387715 was obtained using three methods, logistic regression, a synergy index and the mutual information (MI) index. PMID:19048105

Seitsonen, Sanna P.; Onkamo, Paivi; Peng, Gang; Xiong, Momiao; Tommila, Petri V.; Ranta, Paivi H.; Holopainen, Juha M.; Moilanen, Jukka A.; Palosaari, Tapani; Kaarniranta, Kai; Meri, Seppo; Immonen, Ilkka R.; Jarvela, Irma E.

2008-01-01

199

Structure of a second crystal form of Bence-Jones protein Loc: Strikingly different domain associations in two crystal forms of a single protein  

Microsoft Academic Search

The authors have determined the structure of the immunoglobulin light-chain dimer Loc in a second crystal form that was grown from distilled water. The crystal structure was determined to 2.8-â« resolution; the R factor is 0.22. The two variable domains are related by local 2-fold axes and form an antigen binding pocket. The variable domain-variable domain interaction observed in this

M. Schiffer; C. Ainsworth; Z. B. Xu; W. Carperos; K. Olsen; A. Solomon; F. J. Stevens; C. H. Chang

1989-01-01

200

Evaluation of spheno-occipital synchondrosis: A review of literature and considerations from forensic anthropologic point of view  

PubMed Central

Cranial sutures and synchondrosis have long been studied by forensic scientists, human anatomists, and anthropologists for estimation of age in different population groups. Observation of the closure of spheno-occipital synchondrosis has an important role to play in the estimation of age in the examination of unknown human remains when a skull is brought for examination. The present article reviews the studies conducted on the closure of spheno-occipital synchondrosis and presents a few valuable considerations that would be essential for carrying out research related to closure of spheno-occipital synchondrosis in humans. PMID:24255553

Krishan, Kewal; Kanchan, Tanuj

2013-01-01

201

Neurofibromatosis Type 1: Transcatheter Arterial Embolization for Ruptured Occipital Arterial Aneurysms  

SciTech Connect

Two cases of ruptured aneurysms in the posterior cervical regions associated with type-1 neurofibromatosis treated by transcatheter embolization are reported. Patients presented with acute onset of swelling and pain in the affected areas. Emergently performed contrast-enhanced CT demonstrated aneurysms and large hematomas widespread in the posterior cervical regions. Angiography revealed aneurysms and extravasations of the occipital artery. Patients were successfully treated by percutaneous transcatheter arterial microcoil embolization. Transcatheter arterial embolization therapy was found to be an effective method for treating aneurysmal rupture in the posterior cervical regions occurring in association with type-1 neurofibromatosis. A literature review revealed that rupture of an occipital arterial aneurysm, in the setting of neurofibromatosis type 1, has not been reported previously.

Kanematsu, Masayuki; Kato, Hiroki; Kondo, Hiroshi; Goshima, Satoshi; Tsuge, Yusuke; Kojima, Toshiaki; Watanabe, Haruo [Gifu University Hospital, Department of Radiology (Japan)

2011-02-15

202

Prenatal ultrasound and MRI findings of temporal and occipital lobe dysplasia in a twin with achondroplasia.  

PubMed

Thanatophoric dysplasia, hypochondroplasia and achondroplasia are all caused by FGFR3 (fibroblast growth factor receptor 3) mutations. Neuropathological findings of temporal lobe dysplasia are found in thanatophoric dysplasia, and temporal and occipital lobe abnormalities have been described recently in brain imaging studies of children with hypochondroplasia. We describe twins discordant for achondroplasia, in one of whom the prenatal diagnosis was based on ultrasound and fetal MRI documentation of temporal and occipital lobe abnormalities characteristic of hypochondroplasia, in addition to the finding of short long bones. Despite the intracranial findings suggestive of hypochondroplasia, achondroplasia was confirmed following postnatal clinical and genetic testing. These intracranial abnormalities have not been previously described in a fetus with achondroplasia. PMID:24616001

Pugash, D; Lehman, A M; Langlois, S

2014-09-01

203

Coarse-to-fine categorization of visual scenes in scene-selective cortex.  

PubMed

Neurophysiological, behavioral, and computational data indicate that visual analysis may start with the parallel extraction of different elementary attributes at different spatial frequencies and follows a predominantly coarse-to-fine (CtF) processing sequence (low spatial frequencies [LSF] are extracted first, followed by high spatial frequencies [HSF]). Evidence for CtF processing within scene-selective cortical regions is, however, still lacking. In the present fMRI study, we tested whether such processing occurs in three scene-selective cortical regions: the parahippocampal place area (PPA), the retrosplenial cortex, and the occipital place area. Fourteen participants were subjected to functional scans during which they performed a categorization task of indoor versus outdoor scenes using dynamic scene stimuli. Dynamic scenes were composed of six filtered images of the same scene, from LSF to HSF or from HSF to LSF, allowing us to mimic a CtF or the reverse fine-to-coarse (FtC) sequence. Results showed that only the PPA was more activated for CtF than FtC sequences. Equivalent activations were observed for both sequences in the retrosplenial cortex and occipital place area. This study suggests for the first time that CtF sequence processing constitutes the predominant strategy for scene categorization in the PPA. PMID:24738768

Musel, Benoit; Kauffmann, Louise; Ramanoël, Stephen; Giavarini, Coralie; Guyader, Nathalie; Chauvin, Alan; Peyrin, Carole

2014-10-01

204

Metric sex determination from the basal region of the occipital bone in a documented french sample  

Microsoft Academic Search

\\u000a Abstract  The determination of sex from human skeletal remains is of fundamental importance in both medicolegal and bioarchaeological\\u000a investigations. In the present study, the basal region of the occipital bone in a documented French collection was analyzed\\u000a for sex differences using standard osteometric techniques. The results demonstrated that a low level of sexual dimorphism\\u000a is present in the cranial base of

P. J. Macaluso Jr

2011-01-01

205

Age dependence of fusion of primary occipital sutures: a radiographic study  

Microsoft Academic Search

Purpose  When linear lucency is present in the occipital bone on radiographs throughout childhood, differential diagnosis becomes important because some primary sutures are similar to fractures. The authors here chronicled the normal development of ossification centers, sutures, and synchondroses in the chondrocranium by radiographic examination.Methods  One hundred and twenty-seven children, aged from newborns to 6 years and without any skull base deformities, were

Kuniaki Nakahara; Satoshi Utsuki; Satoru Shimizu; Hideo Iida; Yoshio Miyasaka; Hiroshi Takagi; Hidehiro Oka; Kiyotaka Fujii

2006-01-01

206

Unilateral occipital infarction: evaluation of the risks of developing bilateral loss of vision  

Microsoft Academic Search

Fifty-eight patients with a unilateral infarction in the superficial area supplied by a posterior cerebral artery were followed (mean: 39.6 months). Thirteen (22.4%) developed cortical blindness associated with a delayed contralateral occipital infarction. Advanced age, general vascular risk, a history of strokes, Sylvian border-zone extension of the initial infarct, and an absence of improvement of initial visual field defects were

J Bogousslavsky; F Regli; G van Melle

1983-01-01

207

Metabolic and Molecular Bases of Menkes Disease and Occipital Horn Syndrome  

Microsoft Academic Search

Menkes disease and occipital horn syndrome (OHS) are related disorders of copper transport that involve abnormal neurodevelopment,\\u000a connective tissue problems, and often premature death. Location of the gene responsible for these conditions on the X chromosome\\u000a was indicated by pedigree analysis from the time of these syndromes' earliest descriptions. Characterization of an affected\\u000a female with an X-autosomal translocation was used

1998-01-01

208

Functional asymmetry of human prefrontal cortex in verbal and non-verbal episodic memory as revealed by fMRI.  

PubMed

Functional neuroimaging studies have demonstrated preferential involvement of bilateral prefrontal cortex during episodic memory encoding and retrieval. The aim of the present study is to address the question whether left prefrontal model for encoding holds when highly non-verbal material is used, and which region of the brain is critically related to successful retrieval. To do this, seven normal subjects were investigated using functional magnetic resonance imaging (fMRI) during encoding and retrieval of word and checkerboard pattern. Our results revealed that word encoding activated the left prefrontal cortices and right cerebellum, whereas pattern encoding activated the bilateral middle frontal gyrus, superior parietal lobule, premotor area, and occipital visual cortex. Word-specific activation was found in the ventral prefrontal cortices, and pattern-specific activation located in the right dorsal prefrontal cortex. Conjunction analysis during encoding of word and pattern showed that activity in the left dorsal prefrontal cortex and the right cerebellum might relate to common neural network for encoding regardless of the type of material. Finally, the present study demonstrates strong association between the left ventral prefrontal cortex and retrieval success for word. The evidence, that both encoding and retrieval of words activated the left ventral prefrontal cortex, indicates that this area is involved in active and strategic operation of the mnemonic representation. A lack of the right prefrontal activation during retrieval was interpreted as that activity in this region might relate to retrieval effort rather than success. PMID:10666559

Iidaka, T; Sadato, N; Yamada, H; Yonekura, Y

2000-01-01

209

The Distributed Auditory Cortex  

PubMed Central

A synthesis of cat auditory cortex (AC) organization is presented in which the extrinsic and intrinsic connections interact to derive a unified profile of the auditory stream and use it to direct and modify cortical and subcortical information flow. Thus, the thalamocortical input provides essential sensory information about peripheral stimulus events, which AC redirects locally for feature extraction, and then conveys to parallel auditory, multisensory, premotor, limbic, and cognitive centers for further analysis. The corticofugal output influences areas as remote as the pons and the cochlear nucleus, structures whose effects upon AC are entirely indirect, and has diverse roles in the transmission of information through the medial geniculate body and inferior colliculus. The distributed AC is thus construed as a functional network in which the auditory percept is assembled for subsequent redistribution in sensory, premotor, and cognitive streams contingent on the derived interpretation of the acoustic events. The confluence of auditory and multisensory streams likely precedes cognitive processing of sound. The distributed AC constitutes the largest and arguably the most complete representation of the auditory world. Many facets of this scheme may apply in rodent and primate AC as well. We propose that the distributed auditory cortex contributes to local processing regimes in regions as disparate as the frontal pole and the cochlear nucleus to construct the acoustic percept. PMID:17329049

Winer, Jeffery A.; Lee, Charles C.

2009-01-01

210

Dominant occipital (alpha) rhythm frequency in early stage Alzheimer's disease and depression.  

PubMed

The sinusoidal 8-13 Hz wave form that dominates in the occipital EEG record during relaxed wakefulness is known as alpha rhythm or dominant occipital rhythm. The frequency of this rhythm is known to decrease with normal aging with organic brain diseases. Here we report dominant occipital frequency (DOF) data for 41 early stage AD patients, 50 age-, sex- and health-matched control subjects and 22 subjects with major depressive disorder. DOF was assessed blindly for each subject from 10 or more samples during relaxed wakefulness in an all-night polysomnogram. Mean DOF was significantly lower in the AD (mean +/- S.D. was 8.24 +/- 1.04) than control group (9.48 +/- 0.57; F = 56, P less than 0.001). Mean DOF was also significantly lower in the depressed than control group (9.20 +/- 0.50 vs. 9.48, F = 5.0, P less than 0.05). In discriminant analyses, DOF achieved an overall correct classification rate of 77% for AD vs. control subjects, and 72% for AD vs. depressed subjects. These results indicate that DOF may be useful in identifying early stages of AD in healthy, drug-free populations. PMID:2479521

Prinz, P N; Vitiello, M V

1989-11-01

211

[Transient charles bonnet syndrome after excision of a right occipital meningioma: a case report].  

PubMed

Charles Bonnet syndrome is a condition characterized by visual hallucinations. These simple or complex visual hallucinations are more common in elderly individuals with impaired peripheral vision. The current report describes a case of transient Charles Bonnet syndrome appearing after the removal of a meningioma. The patient was a 61-year-old man who already had impaired visual acuity due to diabetic retinopathy. Brain MRI revealed a cystic tumor severely compressing the right occipital lobe. Starting on day 2 postoperatively, the patient was troubled by recurring visual hallucinations involving people, flowers, pictures, and familiar settings(the train and a coffee shop). These continued for 3.5 months. This period roughly coincided with the time for the occipital lobe to recover from the compression caused by the tumor, a fact that was confirmed by several MRI scans. ¹²³I-IMP SPECT performed 1 month after the surgical operation showed an area of hypoperfusion in the right parieto-occipital lobe. Based on the patient's clinical course and MRI findings, the mechanism of onset of visual hallucinations in this patient was put forward. The release of pressure in the brain by tumor removal and subsequent recovery changed the blood flow to the brain. This triggered visual hallucinations in the patient, who was already predisposed to developing Charles Bonnet syndrome because of diabetic retinopathy. This case is interesting since it indicates that central neurological factors, as well as visual deficits, may induce the appearance of visual hallucinations in Charles Bonnet syndrome. PMID:24807549

Arai, Takao; Hasegawa, Yuzuru; Tanaka, Toshihide; Kato, Naoki; Watanabe, Mitsuyoshi; Nakamura, Aya; Murayama, Yuichi

2014-05-01

212

Neurological and neuropsychological characteristics of occipital, occipito-temporal and occipito-parietal infarction.  

PubMed

Neuropsychological deficits after occipital infarction are most often described in case studies and only a small sample of studies has attempted to exactly correlate the anatomical localization of lesions with associated neuropsychological symptoms. The present study investigated a large number of patients (N = 128) in order to provide an overview of neurological and neuropsychological deficits after occipital, occipito-temporal and occipito-parietal infarction. A particular approach of the study was to define exact anatomical correlates of neuropsychological dysfunction by using voxel-based lesion-symptom mapping (VLSM) in 61 patients. In addition to a visual field defect and phosphenes, patients often reported anomia, difficulties in reading and memory deficits. Visual disorders, such as achromatopsia, akinetopsia or prosopagnosia, were rarely reported by the patients. Memory and visual disorders were diagnosed efficiently using simple clinical screening tests, such as the Rey-Osterrieth Complex Figure Test for immediate recall, the Demtect and the Lang Stereo Test. Visual field defects, reading disorders and the perception of phosphenes were associated primarily with lesions of the calcarine sulcus. Anomia and memory deficits were related to lesions of the occipital inferior gyrus, the lingual gyrus and hippocampus, as well as to lesions of principal white matter tracts. PMID:23206528

Kraft, Antje; Grimsen, Cathleen; Kehrer, Stefanie; Bahnemann, Markus; Spang, Karoline; Prass, Maren; Irlbacher, Kerstin; Köhnlein, Martin; Lipfert, Anika; Brunner, Freimuth; Kastrup, Andreas; Fahle, Manfred; Brandt, Stephan A

2014-07-01

213

iLoc-Hum: using the accumulation-label scale to predict subcellular locations of human proteins with both single and multiple sites.  

PubMed

Although numerous efforts have been made for predicting the subcellular locations of proteins based on their sequence information, it still remains as a challenging problem, particularly when query proteins may have the multiplex character, i.e., they simultaneously exist, or move between, two or more different subcellular location sites. Most of the existing methods were established on the assumption: a protein has one, and only one, subcellular location. Actually, recent evidence has indicated an increasing number of human proteins having multiple subcellular locations. This kind of multiplex proteins should not be ignored because they may bear some special biological functions worthy of our attention. Based on the accumulation-label scale, a new predictor, called iLoc-Hum, was developed for identifying the subcellular localization of human proteins with both single and multiple location sites. As a demonstration, the jackknife cross-validation was performed with iLoc-Hum on a benchmark dataset of human proteins that covers the following 14 location sites: centrosome, cytoplasm, cytoskeleton, endoplasmic reticulum, endosome, extracellular, Golgi apparatus, lysosome, microsome, mitochondrion, nucleus, peroxisome, plasma membrane, and synapse, where some proteins belong to two, three or four locations but none has 25% or higher pairwise sequence identity to any other in the same subset. For such a complicated and stringent system, the overall success rate achieved by iLoc-Hum was 76%, which is remarkably higher than that by any of the existing predictors that also have the capacity to deal with this kind of system. Further comparisons were also made via two independent datasets; all indicated that the success rates by iLoc-Hum were even more significantly higher than its counterparts. As a user-friendly web-server, iLoc-Hum is freely accessible to the public at or . For the convenience of most experimental scientists, a step-by-step guide is provided on how to use the web-server to get the desired results by choosing either a straightforward submission or a batch submission, without the need to follow the complicated mathematical equations involved. PMID:22134333

Chou, Kuo-Chen; Wu, Zhi-Cheng; Xiao, Xuan

2012-02-01

214

Word or word-like? Dissociating orthographic typicality from lexicality in the left occipito-temporal cortex.  

PubMed

Prior lesion and functional imaging studies have highlighted the importance of the left ventral occipito-temporal (LvOT) cortex for visual word recognition. Within this area, there is a posterior-anterior hierarchy of subregions that are specialized for different stages of orthographic processing. The aim of the present fMRI study was to dissociate the effects of subword orthographic typicality (e.g., cider [high] vs. cynic [low]) from the effect of lexicality (e.g., pollen [word] vs. pillen [pseudoword]). We therefore orthogonally manipulated the orthographic typicality of written words and pseudowords (nonwords and pseudohomophones) in a visual lexical decision task. Consistent with previous studies, we identified greater activation for pseudowords than words (i.e., an effect of lexicality) in posterior LvOT cortex. In addition, we revealed higher activation for atypical than typical strings, irrespective of lexicality, in a left inferior occipital region that is posterior to LvOT cortex. When lexical decisions were made more difficult in the context of pseudohomophone foils, left anterior temporal activation also increased for atypical relative to typical strings. The latter finding agrees with the behavior of patients with progressive anterior temporal lobe degeneration, who have particular difficulty recognizing words with atypical orthography. The most novel outcome of this study is that, within a distributed network of regions supporting orthographic processing, we have identified a left inferior occipital region that is particularly sensitive to the typicality of subword orthographic patterns. PMID:20429854

Woollams, Anna M; Silani, Giorgia; Okada, Kayoko; Patterson, Karalyn; Price, Cathy J

2011-04-01

215

Is there a vestibular cortex?  

Microsoft Academic Search

Very different areas of the primate cortex have been labelled as `vestibular'. However, no clear concept has emerged as to where and how the vestibular information is processed in the cerebral cortex. On the basis of data from single-unit recordings and tracer studies, the present article gives statistical evidence of the existence of a well-defined vestibular cortical system. Because the

W. O. Guldin; O. J. Grüsser

1998-01-01

216

Combined direct and indirect reconstructive vascular surgery on the fronto-parieto-occipital region in Moyamoya disease  

Microsoft Academic Search

Between January 1992 and December 1995, eight patients with Moyamoya disease, aged from 2 to 39 years, underwent encephalo-duro-arterio-myo-synangiosis (EDAMS) on the frontal region, superficial temporal artery to middle cerebral artery (STA–MCA) anastomosis combined with encephalo-myo-synangiosis (EMS) on the parietal region and encephaloduro-arterio-synangiosis (EDAS) on the occipital region using the frontal and parietal branch of the STA and the occipital

Dal-Soo Kim; Dae-Kon Kye; Kyoung-Suck Cho; Jin-Un Song; Joon-Ki Kang

1997-01-01

217

Suppression of ponto-geniculo-occipital waves by neurotoxic lesions of pontine caudo-lateral peribrachial cells  

Microsoft Academic Search

Ponto-geniculo-occipital waves precede rapid eye movement sleep and play an important role in triggering and maintaining rapid eye movement sleep. Ponto-geniculo-occipital waves have been implicated in several important functions such as sensorimotor integration, learning, cognition, development of the visual system, visual hallucination, and startle response. Peribrachial area neurons have long been thought to play a key role in the triggering

S. Datta; J. A. Hobson

1995-01-01

218

Hyperfamiliarity for unknown faces after left lateral temporo-occipital venous infarction: a double dissociation with prosopagnosia  

Microsoft Academic Search

Right hemisphere dominance in face processing is well established and unilateral right inferior temporo-occipital damage can result in prosopagnosia. Here, we describe a 21-year-old right-handed woman with acute impairment in face recognition that selectively concerned unfamiliar faces, following a focal left lateral temporo-occipital venous infarct. She was severely impaired in discerning that unknown people seen in everyday life were unfamiliar,

Patrik Vuilleumier; Christine Mohr; Nathalie Valenza; Corinne Wetzel; Theodor Landis

2003-01-01

219

Relationship of Visual Cortex Function and Visual Acuity in Anisometropic Amblyopic Children  

PubMed Central

Purpose: To detect the functional deficit of the visual cortex in anisometropic amblyopia children using functional magnetic resonance imaging (fMRI) technique, and investigate the relationship between visual acuity and visual cortex function. Methods: Blood oxygenation level-dependent fMRI (BOLD-fMRI) was performed in ten monocular anisometropic amblyopia children and ten normal controls. fMRI images were acquired in two runs with visual stimulation delivered separately through the sound and amblyopic eyes. Measurements were performed in cortical activation of striate and extrastriate areas at the occipital lobe. The relationship between cortex function and visual acuity was analyzed by Pearson partial analysis. Results: The activation areas of both the striate and extrastriate cortices in the amblyopic eyes were significantly lower than that of the sound fellow eyes. No relationship was found between the striate and extrastriate cortex activation. No relationship was found between the visual cortical activation of striate, extrastriate areas and visual acuity of anisometropic amblyopes. Conclusions: BOLD-fMRI revealed the independent striate and extrastriate cortical deficits in anisometropic amblyopes. In addition, the visual acuity lesion and the striate and extrastriate cortical deficits were not parallel, and results of fMRI examination have much potential value in the evaluation of amblyopia. PMID:22211099

Li, Chuanming; Cheng, Lin; Yu, Qiongwu; Xie, Bing; Wang, Jian

2012-01-01

220

Motor activity and imagery modulate the body-selective region in the occipital-temporal area: a near-infrared spectroscopy study.  

PubMed

The extrastriate body area (EBA) lies in the occipital-temporal cortex and has been described as a "body-selective" region that responds when viewing other people's bodies. Recently, several studies have reported that EBA is also modulated when the subject moves or imagines moving their own body, even without visual feedback. The present study involved 3 experiments, wherein the first experiment was conducted to examine whether near-infrared spectroscopy (NIRS) could capture any activity in the EBA when viewing images of bodies. The second experiment was designed to elucidate whether this region also responds when the subjects move their own body, and the third to observe whether imagining carrying out a movement would activate EBA. Images of human bodies and chairs were used as the stimuli for the first experiment, simple hand movements carried out by the subject were used for the second and the act of imagining hand movements for the third. Our results confirmed that the region we defined as EBA was clearly activated when the subject viewed images of human bodies, carried out movements of their own body and imagined moving parts of their own body, thus demonstrating the usefulness of NIRS as a new brain imaging method. Moreover, we found a gender-based difference when imagining movement; male subjects showed a greater response than female subjects. This may reflect a gender difference in imagery skills; however, further research is needed to verify this hypothesis. PMID:19733214

Ishizu, Tomohiro; Noguchi, Asuka; Ito, Yoshie; Ayabe, Tomoaki; Kojima, Shozo

2009-11-01

221

Visual cortex in aging and Alzheimer's disease: changes in visual field maps and population receptive fields.  

PubMed

Although several studies have suggested that cortical alterations underlie such age-related visual deficits as decreased acuity, little is known about what changes actually occur in visual cortex during healthy aging. Two recent studies showed changes in primary visual cortex (V1) during normal aging; however, no studies have characterized the effects of aging on visual cortex beyond V1, important measurements both for understanding the aging process and for comparison to changes in age-related diseases. Similarly, there is almost no information about changes in visual cortex in Alzheimer's disease (AD), the most common form of dementia. Because visual deficits are often reported as one of the first symptoms of AD, measurements of such changes in the visual cortex of AD patients might improve our understanding of how the visual system is affected by neurodegeneration as well as aid early detection, accurate diagnosis and timely treatment of AD. Here we use fMRI to first compare the visual field map (VFM) organization and population receptive fields (pRFs) between young adults and healthy aging subjects for occipital VFMs V1, V2, V3, and hV4. Healthy aging subjects do not show major VFM organizational deficits, but do have reduced surface area and increased pRF sizes in the foveal representations of V1, V2, and hV4 relative to healthy young control subjects. These measurements are consistent with behavioral deficits seen in healthy aging. We then demonstrate the feasibility and first characterization of these measurements in two patients with mild AD, which reveal potential changes in visual cortex as part of the pathophysiology of AD. Our data aid in our understanding of the changes in the visual processing pathways in normal aging and provide the foundation for future research into earlier and more definitive detection of AD. PMID:24570669

Brewer, Alyssa A; Barton, Brian

2014-01-01

222

Retrosplenial cortex connectivity in schizophrenia.  

PubMed

In this paper, we build on our previous analysis [Bluhm, R.L., Miller, J., Lanius, R.A., Osuch, E.A., Boksman, K., Neufeld, R.W.J., et al., 2007 Spontaneous low-frequency fluctuations in the BOLD signal in schizophrenic patients: anomalies in the default network. Schizophrenia Bulletin 33, 1004-1012] of resting state connectivity in schizophrenia by examining alterations in connectivity of the retrosplenial cortex. We have previously demonstrated altered connectivity of the posterior cingulate/precuneus, particularly with other regions of the "default network" (which includes the medial prefrontal cortex and bilateral lateral parietal cortex). It was hypothesized that the retrosplenial cortex would show aberrant patterns of connectivity with regions of the default network and regions associated with memory. Patients with schizophrenia (N=17) and healthy controls (N=17) underwent a 5.5-min resting functional magnetic resonance imaging scan. Lower correlations were observed in patients with schizophrenia than in healthy controls between the retrosplenial cortex and both the temporal lobe and regions of the default network. In patients with schizophrenia, activity in the retrosplenial cortex correlated negatively with activity in bilateral anterior cingulate gyrus/medial prefrontal cortex (BA 32/10), despite the fact that these regions, as part of the default network, were expected to show positive correlations in activity. Connectivity of the retrosplenial cortex was greater in patients with more positive symptoms with areas previously associated with hallucinations, particularly the left superior temporal gyrus. These results suggest that spontaneous activity in the retrosplenial cortex during rest is altered in patients with schizophrenia. These alterations may help to explain alterations in self-oriented processing in this patient population. PMID:19783410

Bluhm, Robyn L; Miller, Jodi; Lanius, Ruth A; Osuch, Elizabeth A; Boksman, Kristine; Neufeld, Richard W J; Théberge, Jean; Schaefer, Betsy; Williamson, Peter C

2009-10-30

223

R3P-Loc: a compact multi-label predictor using ridge regression and random projection for protein subcellular localization.  

PubMed

Locating proteins within cellular contexts is of paramount significance in elucidating their biological functions. Computational methods based on knowledge databases (such as gene ontology annotation (GOA) database) are known to be more efficient than sequence-based methods. However, the predominant scenarios of knowledge-based methods are that (1) knowledge databases typically have enormous size and are growing exponentially, (2) knowledge databases contain redundant information, and (3) the number of extracted features from knowledge databases is much larger than the number of data samples with ground-truth labels. These properties render the extracted features liable to redundant or irrelevant information, causing the prediction systems suffer from overfitting. To address these problems, this paper proposes an efficient multi-label predictor, namely R3P-Loc, which uses two compact databases for feature extraction and applies random projection (RP) to reduce the feature dimensions of an ensemble ridge regression (RR) classifier. Two new compact databases are created from Swiss-Prot and GOA databases. These databases possess almost the same amount of information as their full-size counterparts but with much smaller size. Experimental results on two recent datasets (eukaryote and plant) suggest that R3P-Loc can reduce the dimensions by seven-folds and significantly outperforms state-of-the-art predictors. This paper also demonstrates that the compact databases reduce the memory consumption by 39 times without causing degradation in prediction accuracy. For readers? convenience, the R3P-Loc server is available online at url:http://bioinfo.eie.polyu.edu.hk/R3PLocServer/. PMID:24997236

Wan, Shibiao; Mak, Man-Wai; Kung, Sun-Yuan

2014-11-01

224

Sequence variants in HTRA1 and LOC387715/ARMS2 and phenotype and response to photodynamic therapy in neovascular age-related macular degeneration in populations from Israel  

PubMed Central

Purpose Single nucleotide polymorphisms (SNPs) in the tightly linked LOC387715/ARMS2 and HTRA1 genes have been associated with age-related macular degeneration (AMD). We tested whether these SNPs are associated with AMD in Israeli populations, if they underlie variable phenotype and response to therapy in neovascular AMD (NVAMD), and if HTRA1 expression in vivo is associated with its promoter variant. Methods Genotyping for the rs10490924 SNP in LOC387715/ARMS2 and the rs11200638 SNP in HTRA1 was performed on 255 NVAMD patients and 119 unaffected controls from Ashkenazi and Sephardic Jewish, and from Arab origins which are the main ethnic groups composing the Israeli population. Genotyping was correlated with phenotype and response to therapy among 143 patients who underwent photodynamic therapy (PDT). HTRA1 mRNA levels in white blood cells (WBCs), measured by quantitative PCR, were correlated with genotype in 27 participants. Results Both SNPs were in almost complete linkage disequilibrium (D'=0.96–1). Homozygotes for the T allele of rs10490924 had an odds ratio (OR) of 8.6, with a 95% confidence interval (CI) of 3.5–20.8, and homozygotes for the A allele of rs11200638 had an OR of 10.7, with a 95% CI of 3.2–35.7, for having AMD (p<0.00001). There was no association among these SNPs and phenotype or response to PDT. HTRA1 mRNA levels in WBCs were not associated with rs11200638 genotypes. Conclusions The rs10490924 SNP in LOC387715/ARMS2 and the rs11200638 SNP in HTRA1 are strongly associated with NVAMD in this Israeli population. These variants do not have a major contribution to the variable phenotype and response to PDT which characterize NVAMD. PMID:19065273

Meir, Tal; Lederman, Michal; Goldenberg-Cohen, Nitza; Cohen, Yoram; Banin, Eyal; Averbukh, Edward; Hemo, Itzhak; Pollack, Ayala; Axer-Siegel, Ruth; Weinstein, Orly; Hoh, Josephine; Zack, Donald J.; Galbinur, Tural

2008-01-01

225

Feasibility of Use of a Barbed Suture (V-Loc 180) for Quilting the Donor Site in Latissimus Dorsi Myocutaneous Flap Breast Reconstruction  

PubMed Central

Background Latissimus dorsi (LD) myocutaneous flap is a popular method of breast reconstruction which can be associated with high incidence of seroma formation. Quilting sutures at the harvest site are used to reduce this. Barbed sutures are self anchoring sutures which avoid multiple knotting and can be useful in quilting. Methods A retrospective analysis of prospectively maintained database of patients who underwent LD flap breast reconstruction between January 2009 and January 2011 was carried out. Seroma formation at the harvest site, wound related complications, inpatient stay and duration of surgery were analysed and a comparison was made between two groups where quilting was done with barbed (V-Loc) suture and conventional polydioxanone (PDS) II sutures. Results Fifty-seven patients were included of which 33 had quilting by V-Loc sutures and in 24 patients PDS II suture was used. Median age in the PDS group was 55 years (interquartile range [IQR)], 45 to 61 years) which was comparable to the V-Loc group (53 years [IQR, 48 to 59 years]; P-value 0.948). Sixteen patients (28%) had significant seroma formation and 5 (9%) patients developed superficial wound dehiscence. Incidences of seroma or wound complications were comparable (P-value 0.378 and 1.00, respectively). Secondary outcomes such as total duration of surgery, total inpatient stay, total amount of drain at the donor site were also similar in two groups. Conclusions Use of barbed sutures for quilting the donor site in LD flap reconstruction is a feasible option and the associated seroma formation and wound complications are comparable with conventional sutures. PMID:23532830

Hussain, Tasadooq; Mahapatra, Tapan Kumar; McManus, Penelope Louise; Kneeshaw, Peter John

2013-01-01

226

Right-frontal slow negative potentials evoked by occipital TMS are reduced in NREM sleep.  

PubMed

Occipital transcranial magnetic stimulation applied in a task-free experimental setup leads to enhanced relative negativity of frontally recorded evoked slow potentials under the influence of caffeine (Murd et al., 2010 [26]). We tested whether this increased negativity could be reversed when a similar magnetic stimulation is applied during quiet sleep where consciousness is absent. Consistently with the hypothesis, non-REM sleep led to relative more positive slow brain potentials, compared to wakefulness. This effect was lateralized to the right hemisphere. We conclude that TMS indeed elicits slow negative potentials in higher arousal states, but the effect has hemispheric specificity depending on how arousal is manipulated. PMID:21335058

Stamm, Mihkel; Aru, Jaan; Bachmann, Talis

2011-04-15

227

miR-31 and its host gene lncRNA LOC554202 are regulated by promoter hypermethylation in triple-negative breast cancer  

PubMed Central

Background microRNAs have been established as powerful regulators of gene expression in normal physiological as well as in pathological conditions, including cancer progression and metastasis. Recent studies have demonstrated a key role of miR-31 in the progression and metastasis of breast cancer. Downregulation of miR-31 enhances several steps of the invasion-metastasis cascade in breast cancer, i.e., local invasion, extravasation and survival in the circulation system, and metastatic colonization of distant sites. miR-31 exerts its metastasis-suppressor activity by targeting a cohort of pro-metastatic genes, including RhoA and WAVE3. The molecular mechanisms that lead to the loss of miR-31 and the activation of its pro-metastatic target genes during these specific steps of the invasion-metastasis cascade are however unknown. Results In the present report, we identify promoter hypermethylation as one of the major mechanisms for silencing miR-31 in breast cancer, and in the triple-negative breast cancer (TNBC) cell lines of basal subtype, in particular. miR-31 maps to the intronic sequence of a novel long non-coding (lnc)RNA, LOC554202 and the regulation of its transcriptional activity is under control of LOC554202. Both miR-31 and the host gene LOC554202 are down-regulated in the TNBC cell lines of basal subtype and over-expressed in the luminal counterparts. Treatment of the TNBC cell lines with either a de-methylating agent alone or in combination with a de-acetylating agent resulted in a significant increase of both miR-31 and its host gene, suggesting an epigenetic mechanism for the silencing of these two genes by promoter hypermethylation. Finally, both methylation-specific PCR and sequencing of bisulfite-converted DNA demonstrated that the LOC554202 promoter-associated CpG island is heavily methylated in the TNBC cell lines and hypomethylated in the luminal subtypes. Conclusion Loss of miR-31 expression in TNBC cell lines is attributed to hypermethylation of its promoter-associated CpG island. Together, our results provide the initial evidence for a mechanism by which miR-31, an important determinant of the invasion metastasis cascade, is regulated in breast cancer. PMID:22289355

2012-01-01

228

Inhibition and the right inferior frontal cortex  

Microsoft Academic Search

It is controversial whether different cognitive functions can be mapped to discrete regions of the prefrontal cortex (PFC). The localisationist tradition has associated one cognitive function – inhibition – by turns with dorsolateral prefrontal cortex (DLPFC), inferior frontal cortex (IFC), or orbital frontal cortex (OFC). Inhibition is postulated to be a mechanism by which PFC exerts its effects on subcortical

Adam R. Aron; Trevor W. Robbins; Russell A. Poldrack

2004-01-01

229

Perspective Mapping Behavioral Repertoire onto the Cortex  

E-print Network

of the cerebral cortex is that ``like attracts like.'' The cortex is organized to maximize nearest neighborNeuron Perspective Mapping Behavioral Repertoire onto the Cortex Michael S.A. Graziano1,* and Tyson: graziano@princeton.edu DOI 10.1016/j.neuron.2007.09.013 A traditional view of the motor cortex

Graziano, Michael

230

Seghier et al. Cerebral Cortex (to appear) MOVING ILLUSORY CONTOURS ACTIVATE PRIMARY VISUAL CORTEX  

E-print Network

Seghier et al. Cerebral Cortex (to appear) MOVING ILLUSORY CONTOURS ACTIVATE PRIMARY VISUAL CORTEX2009 Author manuscript, published in "Cerebral Cortex / Cerebral Cortex (Cary) 2000;10(7):663-70" #12;Seghier et al. Cerebral Cortex (to appear) Abstract Identifying the cortical areas activated by illusory

Paris-Sud XI, Université de

231

MRI volumetry of prefrontal cortex  

NASA Astrophysics Data System (ADS)

Prefrontal cortex volumetry by brain magnetic resonance (MR) is required to estimate changes postulated to occur in certain psychiatric and neurologic disorders. A semiautomated method with quantitative characterization of its performance is sought to reliably distinguish small prefrontal cortex volume changes within individuals and between groups. Stereological methods were tested by a blinded comparison of measurements applied to 3D MR scans obtained using an MPRAGE protocol. Fixed grid stereologic methods were used to estimate prefrontal cortex volumes on a graphic workstation, after the images are scaled from 16 to 8 bits using a histogram method. In addition images were resliced into coronal sections perpendicular to the bicommissural plane. Prefrontal cortex volumes were defined as all sections of the frontal lobe anterior to the anterior commissure. Ventricular volumes were excluded. Stereological measurement yielded high repeatability and precision, and was time efficient for the raters. The coefficient of error was cortex boundaries on 3D images was critical to obtaining accurate measurements. MR prefrontal cortex volumetry by stereology can yield accurate and repeatable measurements. Small frontal lobe volume reductions in patients with brain disorders such as depression and schizophrenia can be efficiently assessed using this method.

Sheline, Yvette I.; Black, Kevin J.; Lin, Daniel Y.; Pimmel, Joseph; Wang, Po; Haller, John W.; Csernansky, John G.; Gado, Mokhtar; Walkup, Ronald K.; Brunsden, Barry S.; Vannier, Michael W.

1995-05-01

232

Age estimation of immature human skeletal remains using the post-natal development of the occipital bone.  

PubMed

Whenever age cannot be estimated from dental formation in immature human skeletal remains, other methods are required. In the post-natal period, development of the skeleton provides alternative age indicators, namely, those associated with skeletal maturity of the cranium. This study wishes to document the age at which the various ossification centres in the occipital bone fuse and provide readily available developmental probabilistic information for use in age estimation. A sample of 64 identified immature skeletons between birth and 8 years of age from the Lisbon collection was used (females?=?29, males?=?35). Results show that fusion occurs first in the posterior intra-occipital synchondrosis and between the jugular and condylar limbs of the lateral occipital to form the hypoglossal canal (1-4 years), followed by the anterior intra-occipital (3-7 years). Fusion of the post-natal occipital does not show differences in timing between males and females. Relative to other published sources, this study documents first and last ages of fusion of several ossification centres and the posterior probabilities of age given a certain stage of fusion. Given the least amount of overlap in stages of fusion, the closure of the hypoglossal canal provides the narrowest estimated age with the highest probability of age. PMID:23306521

Cardoso, H F V; Gomes, J; Campanacho, V; Marinho, L

2013-09-01

233

Vascular complications (splenic and hepatic artery aneurysms) in the occipital horn syndrome: report of a patient and review of the literature  

Microsoft Academic Search

We report an 18-year-old boy with occipital horn syndrome who developed aneurysms of the splenic and hepatic arteries. Occipital\\u000a horn syndrome, also called X-linked cutis laxa or Ehlers-Danlos syndrome (EDS) type IX, is characterised by a skeletal dysplasia\\u000a which includes occipital horns, broad clavicles, deformed radii, ulnae and humeri, narrow rib cage, undercalcified long bones\\u000a and coxa valga. Distinctive features

Hans-Joachim Mentzel; Jörg Seidel; Susanna Vogt; Lothar Vogt; Werner A. Kaiser

1999-01-01

234

Hypoplasia of the basioccipital bone and persistance of the spheno-occipital synchondrosis in a patient with transitory supplementary fissure of the basioccipital  

Microsoft Academic Search

The author had the opportunity to observe the progressive development of a special form of basilar impression characterized by transitory supplementary fissure of the basi-occipital bone, persistance of the spheno-occipital synchondrosis and hypoplasia of the basi-occipital. He proposes to dissociate the general concept of basilar impression and to consider anatomo-clinical entities such as the example described in this paper.

A. Wackenheim; Service de Radiologie

1985-01-01

235

Stormy onset with prolonged loss of consciousness in benign childhood epilepsy with occipital paroxysms.  

PubMed Central

In nine of 62 children with benign occipital epilepsy (BOE) the onset was stormy and alarming. The first and often only seizure was characterised by prolonged loss of consciousness lasting up to 12 hours, suggesting an acute cerebral insult. In all but one case there was a tonic aversion either of eyes alone or of both head and eyes which was interpreted as conjugate deviation. The other accompanying ictal motor phenomena were either partial or generalised convulsions. In five patients the seizure was heralded by a headache, and in five cases was accompanied by vomiting. The seizure began with visual symptoms in only one patient. The seizure occurred while awake in seven and during sleep in two. The age at onset was from 3 1/4 to 10 years. Interictal EEGs showed occipital discharges typical of BOE, and the clinical course was benign. In four cases a few partial or complex partial seizures recurred during subsequent anticonvulsant therapy, but in five cases seizures never recurred. Anticonvulsants were discontinued in five patients who remained free from seizures for one to 11 1/2 years after withdrawal of treatment. Sudden coma in a child associated with focal features such as tonic deviation of the head or eyes or both may represent a benign seizure disorder. PMID:1548498

Kivity, S; Lerman, P

1992-01-01

236

Analysis of time of closure of the spheno-occipital synchondrosis using computed tomography.  

PubMed

Current knowledge concerning closure of the spheno-occipital synchondrosis is inadequate for age estimation purposes in that of the few detailed studies conducted, these demonstrate considerable variation concerning the age at which the synchondrosis commences and completes fusion, thus creating uncertainty for forensic investigators who may use this developmental feature for age determinations. The aim of the present study was to determine the sequence and timing of closure of the spheno-occipital synchondrosis for a large sample of a modern Australian population to assess if this age marker is a useful tool for age estimation for individuals around the age of 18 years. The sample consisted of 666 individuals in the age range 15-25 years, who were admitted to the Victorian Institute of Forensic Medicine (VIFM) mortuary and who had undergone routine full body multi-slice CT imaging. Results show that fusion was well underway by the age of 15 years and was complete by 17 years. Fusion begins superiorly and progresses inferiorly. Persistence of a scar at the site of fusion was demonstrated through to age 25 years. After the age of 16 years there was no significant difference in progress of fusion between males and females. The study showed that this age marker is of limited value for age estimations around the age of 18 years in this population. PMID:20451338

Bassed, Richard B; Briggs, C; Drummer, Olaf H

2010-07-15

237

Radiation-induced malignant fibrous histiocytoma of the occipital: a case report.  

PubMed

Malignant fibrous histiocytoma (MFH) is a rare neoplasm exhibiting a propensity for aggressive clinical behavior. Effective treatment modality is surgical resection with wide margins, but its rate of recurrence and metastasis is still high. Early detection and complete excision of the tumor is necessary. A MFH of the occipital developed in a 51-year-old woman eight years after surgery and radiation for medulloblastoma of the cerebellar vermis. The secondary neoplasm arose at the site of tumor resection within the irradiated field, and was resected. The development of sarcomas is a recognized complication of radiation therapy. The final diagnosis after the operation was MFH. Radiation-induced sarcoma (RIS) is well known, but radiation-induced MFH is relatively rare in the head and neck region, especially in the occipital. The imaging findings are not diagnosis specific, but strict follow-up within the radiation field by computerized tomography (CT) and magnetic resonance imaging (MRI) and appreciation of the expected latency period may help in providing the diagnosis of RIS. PMID:24742094

Zhang, Guo-Bin; Li, Jian; Zhang, Peng-Fei; Han, Li-Jiang; Zhang, Jun-Ting

2014-01-01

238

Occipital nerve stimulation for the treatment of intractable chronic migraine headache: ONSTIM feasibility study  

PubMed Central

Background: Medically intractable chronic migraine (CM) is a disabling illness characterized by headache ?15 days per month. Methods: A multicenter, randomized, blinded, controlled feasibility study was conducted to obtain preliminary safety and efficacy data on occipital nerve stimulation (ONS) in CM. Eligible subjects received an occipital nerve block, and responders were randomized to adjustable stimulation (AS), preset stimulation (PS) or medical management (MM) groups. Results: Seventy-five of 110 subjects were assigned to a treatment group; complete diary data were available for 66. A responder was defined as a subject who achieved a 50% or greater reduction in number of headache days per month or a three-point or greater reduction in average overall pain intensity compared with baseline. Three-month responder rates were 39% for AS, 6% for PS and 0% for MM. No unanticipated adverse device events occurred. Lead migration occurred in 12 of 51 (24%) subjects. Conclusion: The results of this feasibility study offer promise and should prompt further controlled studies of ONS in CM. PMID:20861241

Saper, Joel R; Dodick, David W; Silberstein, Stephen D; McCarville, Sally; Sun, Mark; Goadsby, Peter J

2011-01-01

239

Distinctive Menkes disease variant with occipital horns: Delineation of natural history and clinical phenotype  

SciTech Connect

To delineate further the clinical spectrum of Menkes disease, an X-linked recessive disorder of copper transport, we studied 4 related males, ranging in age from 4-38 years, with a unique phenotype that combines manifestations of classical and mild Menkes disease and occipital horn syndrome (OHS). The propositus, an 18-year-old man, was evaluated following an intracerebral hemorrhage at age 15 years and was noted to have marked hypotonia, motor delay with mental retardation, bladder diverticula, failure to thrive, and diarrhea from infancy; seizures from age 3 years; and abnormal hair (pili torti) and face, cutis laxa, and multiple joint dislocations. Radiographic abnormalities included occipital exostoses, tortuous cerebral blood vessels with multiple branch occlusions, and hammer-shaped clavicles. Biochemical studies demonstrated reduced copper and ceruloplasmin levels in serum, and abnormal plasma catecholamine ratios. We reported previously the molecular defect in this family, a splice-site mutation that predicts formation of approximately 20% of the normal Menkes gene product. Here, we detail the clinical course and physical features and radiographic findings in these 4 individuals, and compare their phenotype with classical and mild Menkes and OHS. Unusual Menkes disease variants such as this may escape recognition due to anomalies that appear inconsistent with the diagnosis, particularly prolonged survival and later onset of seizures. Males with mental retardation and connective tissue abnormalities should be evaluated for biochemical evidence of defective copper transport. 28 refs., 8 figs.

Proud, V.K.; Mussell, H.G.; Percy, A.K. [Univ. of Alabama School of Medicine, Birmingham, AL (United States)] [and others] [Univ. of Alabama School of Medicine, Birmingham, AL (United States); and others

1996-10-02

240

Radiation-induced malignant fibrous histiocytoma of the occipital: a case report  

PubMed Central

Malignant fibrous histiocytoma (MFH) is a rare neoplasm exhibiting a propensity for aggressive clinical behavior. Effective treatment modality is surgical resection with wide margins, but its rate of recurrence and metastasis is still high. Early detection and complete excision of the tumor is necessary. A MFH of the occipital developed in a 51-year-old woman eight years after surgery and radiation for medulloblastoma of the cerebellar vermis. The secondary neoplasm arose at the site of tumor resection within the irradiated field, and was resected. The development of sarcomas is a recognized complication of radiation therapy. The final diagnosis after the operation was MFH. Radiation-induced sarcoma (RIS) is well known, but radiation-induced MFH is relatively rare in the head and neck region, especially in the occipital. The imaging findings are not diagnosis specific, but strict follow-up within the radiation field by computerized tomography (CT) and magnetic resonance imaging (MRI) and appreciation of the expected latency period may help in providing the diagnosis of RIS. PMID:24742094

2014-01-01

241

The multifunctional application of microfluidic lab-on-a-chip surface enhanced Raman spectroscopy (LOC-SERS) within the field of bioanalytics  

NASA Astrophysics Data System (ADS)

This contribution will present a variety of applications of lab-on-a-chip surface enhanced Raman spectroscopy in the field of bioanalytic. Beside the quantification and online monitoring of drugs and pharmaceuticals, determination of enzyme activity and discrimination of bacteria are successfully carried out utilizing LOC-SERS. The online-monitoring of drugs using SERS in a microfluidic device is demonstrated for nicotine. The enzyme activity of thiopurine methyltransferase (TPMT) in lysed red blood cells is determined by SERS in a lab-on-a-chip device. To analyse the activity of TPMT the metabolism of 6-mercaptopurine to 6-methylmercaptopurine is investigated. The discrimination of bacteria on strain level is carried out with different E. coli strains. For the investigations, the bacteria are busted by ultra sonic to achieve a high information output. This sample preparation provides the possibility to detect SERS spectra containing information of the bacterial cell walls as well as of the cytoplasm. This contribution demonstrates the great potential of LOC-SERS in the field of bioanalytics.

März, Anne; Mönch, Bettina; Walter, Angela; Bocklitz, Thomas; Schumacher, Wilm; Rösch, Petra; Kiehntopf, Michael; Popp, Jürgen

2011-07-01

242

Reading without the left ventral occipito-temporal cortex  

PubMed Central

The left ventral occipito-temporal cortex (LvOT) is thought to be essential for the rapid parallel letter processing that is required for skilled reading. Here we investigate whether rapid written word identification in skilled readers can be supported by neural pathways that do not involve LvOT. Hypotheses were derived from a stroke patient who acquired dyslexia following extensive LvOT damage. The patient followed a reading trajectory typical of that associated with pure alexia, re-gaining the ability to read aloud many words with declining performance as the length of words increased. Using functional MRI and dynamic causal modelling (DCM), we found that, when short (three to five letter) familiar words were read successfully, visual inputs to the patient’s occipital cortex were connected to left motor and premotor regions via activity in a central part of the left superior temporal sulcus (STS). The patient analysis therefore implied a left hemisphere “reading-without-LvOT” pathway that involved STS. We then investigated whether the same reading-without-LvOT pathway could be identified in 29 skilled readers and whether there was inter-subject variability in the degree to which skilled reading engaged LvOT. We found that functional connectivity in the reading-without-LvOT pathway was strongest in individuals who had the weakest functional connectivity in the LvOT pathway. This observation validates the findings of our patient’s case study. Our findings highlight the contribution of a left hemisphere reading pathway that is activated during the rapid identification of short familiar written words, particularly when LvOT is not involved. Preservation and use of this pathway may explain how patients are still able to read short words accurately when LvOT has been damaged. PMID:23017598

Seghier, Mohamed L.; Neufeld, Nicholas H.; Zeidman, Peter; Leff, Alex P.; Mechelli, Andrea; Nagendran, Arjuna; Riddoch, Jane M.; Humphreys, Glyn W.; Price, Cathy J.

2012-01-01

243

Pulsed radiofrequency to the great occipital nerve for the treatment of intractable postherpetic itch: a case report  

PubMed Central

A patient with intractable postherpetic itch lasting for 1 year was reported. The itch was mainly from the left vertex, frontal and ophthalmic regions and extended to the left neck area. The patient had negative response to the ophthalmic nerve block. Under the initial positive response to the great occipital nerve block, pulsed radiofrequency (PRF) was performed on the position of the great occipital nerve. After 4 months treatment, the itch was completely vanished. This case study demonstrates the effectiveness of PRF for intractable postherpetic itch originating in the head and neck. However, more samples needed to verify this management.

Ding, De-Fang; Li, Rong-Chun; Xiong, Qiu-Ju; Zhou, Ling; Xiang, Hong-Bing

2014-01-01

244

Simultaneous TMS-fMRI of the Visual Cortex Reveals Functional Network, Even in Absence of Phosphene Sensation  

PubMed Central

Phosphene sensation is commonly used to measure cortical excitability during transcranial magnetic stimulation (TMS) of the occipital cortex. However, some individuals lack this perception, and the reason for it is still unknown. In this work, we used functional magnetic resonance imaging (fMRI) to detect brain activation during local TMS of the occipital cortex in twelve healthy subjects. We found that TMS modulated brain activity in areas connected to the stimulation site, even in people unable to see phosphene. However, we observed a trend for a lower blood-oxygenation-level dependent (BOLD) signal, and smaller brain-activation clusters near the stimulated site than in the interconnected brain areas, suggesting that TMS pulse is more effective downstream than at its application site. Furthermore, we noted prominent differences in brain activation/deactivation patterns between subjects who perceived phosphene and those who did not, implying a functional distinction in their neuronal networks that might explain the origin of differences in phosphene generation. PMID:21686319

Caparelli, E.C.; Backus, W.; Telang, F.; Wang, G-J; Maloney, T.; Goldstein, R.Z.; Anschel, D.; Henn, F.

2010-01-01

245

Intradiploic occipital pseudomeningocele in a patient with remote history of surgical treatment of Chiari malformation.  

PubMed

An intradiploic CSF pseudocyst is a rare entity that has been described in association with trauma, as a sequela of untreated hydrocephalus, or occasionally as a congenital finding in older adults. The authors present the case of a woman with a remote history of a posterior fossa intradural procedure, in which she underwent Chiari malformation decompression, Silastic substitute-assisted duraplasty, and occipitocervical fusion; she presented 19 years later with recurrent symptoms of Chiari malformation. She was found to have an occipital intradiploic pseudomeningocele, arising within her dorsal occipitocervical fusion mass and resulting in dorsal hindbrain compression. She underwent a posterior fossa decompression and revision of her failed duraplasty, and she had a good recovery. This case demonstrates intradiploic CSF pseudomeningocele as a rare potential delayed complication of an intradural procedure for the treatment of Chiari malformation with occipitocervical fusion. PMID:25147975

Mahaney, Kelly B; Menezes, Arnold H

2014-11-01

246

Parietal and bi-occipital lobe infarction confounded by ethanol-induced optic neuropathy.  

PubMed

A frequent occurrence in geriatric and chronically ill patients is the exhibition of several simultaneously occurring and confounding health problems. This paper reports the case of a 61-year-old-white male who presented with an extensive history of multiple brain infarcts, hemiparesis, personality changes and varied visual complaints. Tests in the neurooptometric work-up for this patient included static automated perimetry, stereoacuity and optokinetic nystagmus evaluation. The results were suggestive of multiple cerebrovascular accidents which included the right and left occipital lobes as well as the right parietal lobe. This clinical picture was complicated by the presence of nutritional or ethanol-induced optic neuropathy. Emphasis was placed on a detailed sequential history of events and a complete neurological and optometric evaluation to ascertain the multiple foci of cortical infarction. Corroboration of clinical findings was obtained by computerized axial tomography (CT scan). PMID:1813574

Tornatore, C W; Townsend, J C; Selvin, G J

1991-08-01

247

Maxillary changes and occlusal traits in crania with artificial fronto-occipital deformation.  

PubMed

Artificial fronto-occipital deformation of the cranial vault was typical of pre-Columbian cultures in the central Andean coastal regions. We have studied the influence of this deformation on maxillary and mandibular morphology. Measurements were performed on 86 adult Ancon skulls with anteroposterior deformation. Undeformed skulls from the area of Makatampu (n = 52) were used as the control group. To explore the influence of the deformity on occlusion, the skulls were categorized using the Angle classification and the alignment of the interincisor midline. In the group of deformed skulls, there was an increase in lateral growth of the vault and of the base of the skull (P < 0.001), giving rise to a greater interpterygoid width of the maxilla (P < 0.001), and an increase in the transverse diameter of the palatal vault. The mandible presented an increase in the length of the rami (P < 0.001) and in the intercondylar width, with no alteration of mandibular length. The deformed skulls had normal (class I) occlusion, with no displacement of the midline. The difference in the asymmetry index between the two groups was not statistically significant. Artificial fronto-occipital deformation of the cranial vault provoked compensatory lateral expansion of the base that was correlated with the transverse development of the maxilla and mandible. Occlusion and sagittal intermaxillary position were not affected by the cranial deformity. These results provide evidence of the integration between the neurocranium and the viscerocranium in craniofacial development, and support the hypothesis of a compensatory effect of function. PMID:21990029

Jimenez, Publio; Martinez-Insua, Arturo; Franco-Vazquez, Jaime; Otero-Cepeda, Xose Luis; Santana, Urbano

2012-01-01

248

Anatomic study of the occipital condyle and its surgical implications in transcondylar approach  

PubMed Central

Background: Craniovertebral surgeries require the anatomical knowledge of craniovertebral junction. The human occipital condyle (OC) is unique bony structure connecting the cranium and the vertebral column. A lateral approach like transcondylar approach (TA) requires understanding of the relationships between the OC, jugular tubercle, and hypoglossal canal. Hence, the aim of the present study was to analyze the morphological variations in OCs of dry adult human skull. Materials and Methods: The study was carried out on 142 OC of 71 adult human dry skulls (55 males and 16 females). Morphometric parameters such as length, width, thickness, intercondylar distances, and the distances from the OC to the foramen magnum, hypoglossal canal and jugular foramen were measured. In addition, the different locations of the hypoglossal canal orifices in relation to the OC and different shapes of the OC were also noted. Results: The average length, width and height of the OC were found to be 2.2, 1.1 and 0.9 cm. The anterior and posterior intercondylar distances were 2.1 and 3.9 cm, respectively. Maximum and minimum bicondylar distances were 4.5 and 2.6 cm, respectively. The intra-cranial orifice of the hypoglossal canal was found to be present in middle 1/3rd in all skulls (100%), and extra-cranial orifice of the hypoglossal canal was found to be in anterior 1/3rd (98%) in relation to OC. The oval shaped OC (22.5%) was the most predominant type of OC observed in these skulls. Conclusion: Occipital condyle is likely to have variations with respect to shape, length, width and its orientation. Therefore, knowledge of the variations in OC along with careful radiological analysis may help in safe TAs during skull base surgery.

Kalthur, Sneha Guruprasad; Padmashali, Supriya; Gupta, Chandni; Dsouza, Antony S.

2014-01-01

249

Greater occipital nerve injection in primary headache syndromes--prolonged effects from a single injection.  

PubMed

Most patients with primary headache syndromes who have frequent attacks of pain have tenderness in the sub-occipital region. Injection of the greater occipital nerve (GON) with local anesthetic and corticosteroids has been widely used in clinical practice for many years, yet there is no clear understanding of its mechanisms of action. Moreover, there is no current gold-standard of practice regarding GON injections in the management of headache. We audited of our practice to generate hypotheses about the range of primary headaches that might benefit, to determine response rates to power future studies, and to assess whether we should continue to do this procedure. Twenty-six of fifty-seven injections in 54 migraineurs yielded a complete or partial response that lasted for the partial response a median of 30 days. For cluster headache 13 of 22 injections yielded a complete or partial response lasting for a median of 21 days for the partial response. Tenderness over the GON was strongly predictive of outcome, although local anesthesia after the injection was not. The presence or absence of medication overuse did not predict outcome. Apart from two patients with a small patch of alopecia the injection was well tolerated. GON injection is a useful tool in some patients that provides interim relief while other approaches are explored. It is remarkable that in all conditions in which an effect is observed the response time so much exceeds the local anesthetic effect that the mechanism of action may well be through changes in brain nociceptive pathways. PMID:16527404

Afridi, S K; Shields, K G; Bhola, R; Goadsby, P J

2006-05-01

250

Quantitative assessment of diffuse optical tomography sensitivity to the cerebral cortex using a whole-head probe  

NASA Astrophysics Data System (ADS)

We quantify the variability in diffuse optical tomography (DOT) sensitivity over the cortical surface in eight young adult subjects. We use the 10/5 electroencephalography system as a basis for our whole-head optical high-density probe design. The contrast-to-noise ratio (CNR) is calculated along with the percentage of the cortex that is above a CNR = 0 dB threshold. We also quantify the effect of including vasculature on the forward model and list our assumptions that allow us to estimate light penetration depth in the head. We show that using the 10/5 system for the optical probe design allows for the measurement of 37% of the cortical surface on average, with a mean CNR in the visible region of 5.5 dB. Certain anatomical regions, such as the lateral occipital cortex, had a very high percentage above the CNR threshold, while other regions such as the cingulate cortex were not measurable. Vasculature blocked optical sensitivity over 1% of the cortex. Cortical coverage was positively correlated with intracranial volume and relative cerebrospinal fluid volume, and negatively correlated with relative scalp volume and skull volume. These contributions allow experimenters to understand how anatomical variation in a subject population may impact DOT or functional near-infrared spectroscopy measurements.

Perdue, Katherine L.; Fang, Qianqian; Diamond, Solomon G.

2012-05-01

251

Retinotopic and lateralized processing of spatial frequencies in human visual cortex during scene categorization.  

PubMed

Using large natural scenes filtered in spatial frequencies, we aimed to demonstrate that spatial frequency processing could not only be retinotopically mapped but could also be lateralized in both hemispheres. For this purpose, participants performed a categorization task using large black and white photographs of natural scenes (indoors vs. outdoors, with a visual angle of 24° × 18°) filtered in low spatial frequencies (LSF), high spatial frequencies (HSF), and nonfiltered scenes, in block-designed fMRI recording sessions. At the group level, the comparison between the spatial frequency content of scenes revealed first that, compared with HSF, LSF scene categorization elicited activation in the anterior half of the calcarine fissures linked to the peripheral visual field, whereas, compared with LSF, HSF scene categorization elicited activation in the posterior part of the occipital lobes, which are linked to the fovea, according to the retinotopic property of visual areas. At the individual level, functional activations projected on retinotopic maps revealed that LSF processing was mapped in the anterior part of V1, whereas HSF processing was mapped in the posterior and ventral part of V2, V3, and V4. Moreover, at the group level, direct interhemispheric comparisons performed on the same fMRI data highlighted a right-sided occipito-temporal predominance for LSF processing and a left-sided temporal cortex predominance for HSF processing, in accordance with hemispheric specialization theories. By using suitable method of analysis on the same data, our results enabled us to demonstrate for the first time that spatial frequencies processing is mapped retinotopically and lateralized in human occipital cortex. PMID:23574583

Musel, Benoit; Bordier, Cécile; Dojat, Michel; Pichat, Cédric; Chokron, Sylvie; Le Bas, Jean-François; Peyrin, Carole

2013-08-01

252

Benign Nocturnal Childhood Occipital Epilepsy: A New Syndrome with Nocturnal Seizures, Tonic Deviation of the Eyes, and Vomiting  

Microsoft Academic Search

An epileptic syndrome of benign nocturnal childhood occipital epilepsy with excellent prognosis is described. The syndrome is characterized by a clinical ictal triad of nocturnal seizures, tonic deviation of the eyes, and vomiting. There may be marching to involve the head and limbs, ending with a generalized tonic-clonic seizure. Consciousness is usually, but not invariably, disturbed. Infrequent daytime fits may

Chrysostomos P. Panayiotopoulos; Jean Aicardi

1989-01-01

253

Where are inion and endinion? Variations of the exo- and endocranial morphology of the occipital bone during hominin evolution  

Microsoft Academic Search

The occipital bone is frequently investigated in paleoanthropological studies because it has several features that help to differentiate various fossil hominin species. Among these features is the separation between inion and endinion, which has been proposed to be an autapomorphic trait in (Asian) Homo erectus. Methodologies are developed here to quantify for the first time the location of these anatomical

Antoine Balzeau; Dominique Grimaud-Hervé; Emmanuel Gilissen

2011-01-01

254

AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 87:167-171 (1992) Effects of F:ronto-OccipitalCranial Reshaping  

E-print Network

AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 87:167-171 (1992) Effects of F:ronto-OccipitalCranial University, Chicago, Illinois 60611 (J.E.M.) KEY WORDS Cranial growth Artificial deformation, mandible, Peruvian Ancon, ABSTTUCT Cultural reshaping (artificialdeformationor modification)of the neurocranial vault

Cheverud, James M.

255

The insular cortex: a review.  

PubMed

The human insular cortex forms a distinct, but entirely hidden lobe, situated in the depth of the Sylvian fissure. Here, we first review the recent literature on the connectivity and the functions of this structure. It appears that this small lobe, taking up less than 2% of the total cortical surface area, receives afferents from some sensory thalamic nuclei, is (mostly reciprocally) connected with the amygdala and with many limbic and association cortical areas, and is implicated in an astonishingly large number of widely different functions, ranging from pain perception and speech production to the processing of social emotions. Next, we embark on a long, adventurous journey through the voluminous literature on the structural organization of the insular cortex. This journey yielded the following take-home messages: (1) The meticulous, but mostly neglected publications of Rose (1928) and Brockhaus (1940) are still invaluable for our understanding of the architecture of the mammalian insular cortex. (2) The relation of the insular cortex to the adjacent claustrum is neither ontogenetical nor functional, but purely topographical. (3) The insular cortex has passed through a spectacular progressive differentiation during hominoid evolution, but the assumption of Craig (2009) that the human anterior insula has no homologue in the rhesus monkey is untenable. (4) The concept of Mesulam and Mufson (1985), that the primate insula is essentially composed of three concentrically arranged zones, agranular, dysgranular, and granular, is presumably correct, but there is at present much confusion concerning the more detailed architecture of the anterior insular cortex. (5) The large spindle-shaped cells in the fifth layer of the insular cortex, currently known as von Economo neurons (VENs), are not only confined to large-brained mammals, such as whales, elephants, apes, and humans, but also occur in monkeys and prosimians, as well as in the pygmy hippopotamus, the Atlantic walrus, and Florida manatee. Finally, we point out that the human insula presents a unique opportunity for performing an in-depth comparative analysis of the relations between structure and function in a typical sensory and a typical cognitive cortical domain. PMID:22230626

Nieuwenhuys, Rudolf

2012-01-01

256

The Functions of the Orbitofrontal Cortex  

ERIC Educational Resources Information Center

The orbitofrontal cortex contains the secondary taste cortex, in which the reward value of taste is represented. It also contains the secondary and tertiary olfactory cortical areas, in which information about the identity and also about the reward value of odours is represented. The orbitofrontal cortex also receives information about the sight…

Rolls, Edmund T.

2004-01-01

257

Photoacoustic tomography of a rat cerebral cortex  

E-print Network

Photoacoustic tomography of a rat cerebral cortex with a ring-based ultrasonic virtual point Engineering, Optical Imaging Laboratory, Saint Louis, Missouri 63130 Abstract. We image a rat cerebral cortex. In this work, we apply the virtual point detector to PAT of a rat cerebral cortex and show its advantages over a

Wang, Lihong

258

Motor Cortex Reflexes Associated with Learned Movement  

Microsoft Academic Search

In primates, sensory input can generate reflex motor cortex output in association with learned movement when the sensory input has a strong and direct connection to the motor cortex-for example, when a stimulus calling for repositioning of the hand consists of a perturbation of hand position. This finding supports the proposal that neurons of primate motor cortex may function in

Edward V. Evarts

1973-01-01

259

Multiple-time-scale analysis of nonlinear modes in ferroelectric LiNbO3 A. K. Bandyopadhyay,1,* P. C. Ray,2, Loc Vu-Quoc,3, and Arthur R. McGurn4,  

E-print Network

of Mathematics, Govt. College of Engineering & Leather Technology, LB Block, Sector III, Salt Lake, Calcutta. C. Ray,2, Loc Vu-Quoc,3, and Arthur R. McGurn4,§ 1Govt. College of Engineering & Ceramic Technology, Florida 32611, USA 4 Department of Physics, Western Michigan University, Kalamazoo, Michigan 49008

Vu-Quoc, Loc

260

Probabilistic and single-subject retinotopic maps reveal the topographic organization of face patches in the macaque cortex.  

PubMed

Face perception is crucial to survival among social primates. It has been suggested that a group of extrastriate cortical regions responding more strongly to faces than to nonface objects is critical for face processing in primates. It is generally assumed that these regions are not retinotopically organized, as with human face-processing areas, showing foveal bias but lacking any organization with respect to polar angle. Despite many electrophysiological studies targeting monkey face patches, the retinotopic organization of these patches remains largely unclear. We have examined the relationship between cortical face patches and the topographic organization of extrastriate cortex using biologically relevant, phase-encoded retinotopic mapping stimuli in macaques. Single-subject fMRI results indicated a gradual shift from highly retinotopic to no topographic organization from posterior to anterior face patches in inferotemporal cortex. We also constructed a probabilistic retinotopic atlas of occipital and ventral extrastriate visual cortex. By comparing this probabilistic map to the locations of face patches at the group level, we showed that a previously identified posterior lateral temporal face patch (PL) is located within the posterior inferotemporal dorsal (PITd) retinotopic area. Furthermore, we identified a novel face patch posterior PL, which is located in retinotopically organized transitional area V4 (V4t). Previously published coordinates of human PITd coincide with the group-level occipital face area (OFA), according to a probabilistic map derived from a large population, implying a potential correspondence between monkey PL/PITd and human OFA/PITd. Furthermore, the monkey middle lateral temporal face patch (ML) shows consistent foveal biases but no obvious polar-angle structure. In contrast, middle fundus temporal (MF), anterior temporal and prefrontal monkey face patches lacked topographic organization. PMID:25080579

Janssens, Thomas; Zhu, Qi; Popivanov, Ivo D; Vanduffel, Wim

2014-07-30

261

The prefrontal cortex in sleep  

Microsoft Academic Search

Experimental data indicate a role for the prefrontal cortex in mediating normal sleep physiology, dreaming and sleep-deprivation phenomena. During nonrandom-eye-movement (NREM) sleep, frontal cortical activity is characterized by the highest voltage and the slowest brain waves compared to other cortical regions. The differences between the self-awareness experienced in waking and its diminution in dreaming can be explained by deactivation of

Amir Muzur; Edward F. Pace-Schott; J. Allan Hobson

2002-01-01

262

Occipital Artery Function during the Development of 2-Kidney, 1-Clip Hypertension in Rats  

PubMed Central

This study compared the contractile responses elicited by angiotensin II (AII), arginine vasopressin (AVP), and 5-hydroxytryptamine (5-HT) in isolated occipital arteries (OAs) from sham-operated (SHAM) and 2-kidney, 1-clip (2K-1C) hypertensive rats. OAs were isolated and bisected into proximal segments (closer to the common carotid artery) and distal segments (closer to the nodose ganglion) and mounted separately on myographs. On day 9, 2K-1C rats had higher mean arterial blood pressures, heart rates, and plasma renin concentrations than SHAM rats. The contractile responses to AII were markedly diminished in both proximal and distal segments of OAs from 2K-1C rats as compared to those from SHAM rats. The responses elicited by AVP were substantially greater in distal than in proximal segments of OAs from SHAM rats and that AVP elicited similar responses in OA segments from 2K-1C rats. The responses elicited by 5-HT were similar in proximal and distal segments from SHAM and 2K-1C rats. These results demonstrate that continued exposure to circulating AII and AVP in 2K-1C rats reduces the contractile efficacy of AII but not AVP or 5-HT. The diminished responsiveness to AII may alter the physiological status of OAs in vivo. PMID:25140254

Chelko, Stephen P.; Schmiedt, Chad W.; Lewis, Tristan H.; Robertson, Tom P.; Lewis, Stephen J.

2014-01-01

263

Tonic inhibition and ponto-geniculo-occipital-related activities shape abducens motoneuron discharge during REM sleep  

PubMed Central

Eye movements, ponto-geniculo-occipital (PGO) waves, muscular atonia and desynchronized cortical activity are the main characteristics of rapid eye movement (REM) sleep. Although eye movements designate this phase, little is known about the activity of the oculomotor system during REM sleep. In this work, we recorded binocular eye movements by the scleral search-coil technique and the activity of identified abducens (ABD) motoneurons along the sleep–wake cycle in behaving cats. The activity of ABD motoneurons during REM sleep was characterized by a tonic decrease of their mean firing rate throughout this period, and short bursts and pauses coinciding with the occurrence of PGO waves. We demonstrate that the decrease in the mean firing discharge was due to an active inhibition of ABD motoneurons, and that the occurrence of primary and secondary PGO waves induced a pattern of simultaneous but opposed phasic activation and inhibition on each ABD nucleus. With regard to eye movements, during REM sleep ABD motoneurons failed to codify eye position as during alertness, but continued to codify eye velocity. The pattern of tonic inhibition and the phasic activations and inhibitions shown by ABD motoneurons coincide with those reported in other non-oculomotor motoneurons, indicating that the oculomotor system – contrary to what has been accepted until now – is not different from other motor systems during REM sleep, and that all motor systems are receiving similar command signals during this period. PMID:18499728

Escudero, Miguel; Marquez-Ruiz, Javier

2008-01-01

264

Atypical Balance between Occipital and Fronto-Parietal Activation for Visual Shape Extraction in Dyslexia  

PubMed Central

Reading requires the extraction of letter shapes from a complex background of text, and an impairment in visual shape extraction would cause difficulty in reading. To investigate the neural mechanisms of visual shape extraction in dyslexia, we used functional magnetic resonance imaging (fMRI) to examine brain activation while adults with or without dyslexia responded to the change of an arrow’s direction in a complex, relative to a simple, visual background. In comparison to adults with typical reading ability, adults with dyslexia exhibited opposite patterns of atypical activation: decreased activation in occipital visual areas associated with visual perception, and increased activation in frontal and parietal regions associated with visual attention. These findings indicate that dyslexia involves atypical brain organization for fundamental processes of visual shape extraction even when reading is not involved. Overengagement in higher-order association cortices, required to compensate for underengagment in lower-order visual cortices, may result in competition for top-down attentional resources helpful for fluent reading. PMID:23825653

Zhang, Ying; Whitfield-Gabrieli, Susan; Christodoulou, Joanna A.; Gabrieli, John D. E.

2013-01-01

265

Occipital nerve stimulation for intractable chronic cluster headache: new hope for a dreadful disease?  

PubMed

Chronic cluster headache (CCH) is one of the most painful primary headaches. A small percentage of CCH become intractable (iCCH) and is refractory to the majority of preventing drugs. Various invasive and sometimes destructive procedures have been tempted to help these patients, but none gave satisfactory results for the long term. Hypothalamic deep-brain stimulation (hDBS) has recently raised expectations with an average improvement of 50 to 70%, but is not a riskless procedure. Harmless methods were therefore warranted, and in this perspective occipital nerve stimulation (ONS) trials were undertaken. Up to now, nearly 38 iCCH patients benefited from ONS in the available literature and the technique appears to give results similar to hDBS, having the advantage to have much milder side effects. The mechanism by which ONS is efficient in iCCH remains unknown but preliminary results of neurophysiological and imaging studies suggest ONS is just a symptomatic treatment which does not act on the disease generator. We would however advocate ONS as first choice alternative therapy in iCCH. PMID:21510228

Magis, Delphine; Schoenen, Jean

2011-03-01

266

[Transient homonymous hemianopsia due to thrombosis of the confluence of sinuses after occipital transtentorial removal of pineal region tumor].  

PubMed

The authors report a case of 74-year-old woman suffering thrombosis of the confluence of sinuses after the left occipital transtentorial removal of a pineal region epidermoid cyst. Four days after the operation, the patient developed left homonymous hemianopsia. Magnetic resonance imaging revealed a venous infarct in the right occipital lobe and magnetic resonance venography disclosed a signal defect of the posterior part of the confluence of sinuses. The patients' neurological symptom recovered soon after anticoagulation treatment, and magnetic resonance venography after the sixth week showed recanalization of the confluence of sinuses. Although it might be rare, thrombosis of the dural sinus should be recognized as a complication of craniotomy. PMID:21041894

Meguro, Toshinari; Sasaki, Tatsuya; Haruma, Jun; Tanabe, Tomoyuki; Muraoka, Kenichiro; Terada, Kinya; Hirotsune, Nobuyuki; Nishino, Shigeki

2010-10-01

267

Osteoradionecrosis of the cervical vertebrae and occipital bone: A case report and brief review of the literature  

Microsoft Academic Search

Osteoradionecrosis (ORN) is a common complication of radiation therapy. We present the first case reported in the literature of ORN involving the first and second cervical vertebrae and occipital bone in a patient who was treated with surgery and radiation therapy 9 years prior for a TxN3M0 squamous cell carcinoma of the left neck arising from an unknown primary origin.

Alan A. Tan Lim; Daniel W. Karakla; Dale V. Watkins

1999-01-01

268

Modified C1 lateral mass screw insertion using a high entry point to avoid postoperative occipital neuralgia.  

PubMed

For the past decade, a screw-rod construct has been used commonly to stabilize the atlantoaxial joint, but the insertion of the screw through the C1 lateral mass (LM) can cause several complications. We evaluated whether using a higher screw entry point for C1 lateral mass (LM) fixation than in the standard procedure could prevent screw-induced occipital neuralgia. We enrolled 12 consecutive patients who underwent bilateral C1 LM fixation, with the modified screw insertion point at the junction of the C1 posterior arch and the midpoint of the posterior inferior portion of the C1 LM. We measured postoperative clinical and radiological parameters and recorded intraoperative complications, postoperative neurological deficits and the occurrence of occipital neuralgia. Postoperative plain radiographs were used to check for malpositioning of the screw or failure of the construct. Four patients underwent atlantoaxial stabilization for a transverse ligament injury or a C1 or C2 fracture, six patients for os odontoideum, and two patients for C2 metastasis. No patient experienced vertebral artery injury or cerebrospinal fluid leak, and all had minimal blood loss. No patient suffered significant occipital neuralgia, although one patient developed mild, transient unilateral neuralgia. There was also no radiographic evidence of construct failure. Twenty screws were positioned correctly through the intended entry points, but three screws were placed inferiorly (that is, below the arch), and one screw was inserted too medially. When performing C1-C2 fixation using the standard (Harms) construct, surgeons should be aware of the possible development of occipital neuralgia. A higher entry point may prevent this complication; therefore, we recommend that the screw should be inserted into the arch of C1 if it can be accommodated. PMID:23117140

Lee, Sun-Ho; Kim, Eun-Sang; Eoh, Whan

2013-01-01

269

Posterior cranial fossa tumors: Results and prognostic factors in a consecutive series of 14 operated patients by occipital transtentorial approach  

PubMed Central

Background: The objective of our study was to determine the safety and usefulness of performing surgery via occipital transtentorial approach to treat posterior cranial fossa tumors, which is well known as an approach to the pineal region (Poppen's approach). Methods: Fourteen patients with posterior cranial fossa tumors were successfully treated using occipital transtentorial approach between 2007 and 2012. The lesions included five meningiomas, three astrocytomas, two metastases, two hemangioblastomas, one cavernoma, and one dysgerminoma. Results: Lesions were <3 cm in 12 cases and ?3 cm in two cases. Average Karnofsky Performance Status (KPS) scoring at admission was 88.5. Eleven patients scored ?70 and seven patients <70. Average age was 43.1 years. All patients underwent surgical treatment by the same surgical team. All tumors were completely removed surgically without any injury to the venous complex and the adjoining structures. There was no incidence of mortality or morbidity in all patients, and all functional outcomes were good to excellent postoperatively. Postoperative computed tomography (CT) imaging revealed that none of the patients had suffered brain damage or infarction around the cerebellum, brainstem, or occipital lobe. Conclusions: We found that the use of occipital transtentorial approach is strongly supported by the successful removal of posterior cranial fossa tumors without serious complications. Open microneurosurgery is probably still the most effective therapy in improving survival and KPS in patients with posterior cranial fossa tumors, given that the proper surgical technique is used and complications do not occur. This case study has strongly suggested that this approach is very useful, safe, and accurate for removing the tumors of posterior fossa and evaluating the surrounding anatomy, as well as for determining operative strategy. PMID:23050200

Maselli, Giuliano; De Paulis, Danilo; Ricci, Alessandro; Galzio, Renato J.

2012-01-01

270

Neurotransmitters in the cerebral cortex.  

PubMed

This article surveys the conventional neurotransmitters and modulatory neuropeptides that are found in the cerebral cortex and attempts to place them into the perspective of both intracortical circuitry and cortical disease. The distribution of these substances is related, where possible, to particular types of cortical neuron or to afferent or efferent fibers. Their physiological actions, where known, on cortical neurons are surveyed, and their potential roles in disease states such as the dementias, epilepsy, and stroke are assessed. Conventional transmitters that occur in afferent fibers to the cortex from brain-stem and basal forebrain sites are: serotonin, noradrenaline, dopamine, and acetylcholine. All of these except dopamine are distributed to all cortical areas: dopamine is distributed to frontal and cingulate areas only. The transmitter in thalamic afferent systems is unknown. Gamma aminobutyric acid (GABA) is the transmitter used by the majority of cortical interneurons and has a profound effect upon the shaping of receptive field properties. The vast majority of the known cortical peptides are found in GABAergic neurons, and the possibility exists that they may act as trophic substances for other neurons. Levels of certain neuropeptides decline in cases of dementia of cortical origin. Acetylcholine is the only other known transmitter of cortical neurons. It, too, is contained in neurons that also contain a neuropeptide. The transmitter(s) used by excitatory cortical interneurons and by the efferent pyramidal cells is unknown, but it may be glutamate or aspartate. It is possible that excitotoxins released in anoxic disease of the cortex may produce damage by acting on receptors for these or related transmitter agents. PMID:2873211

Jones, E G

1986-08-01

271

Premature closure of the spheno-occipital synchondrosis in Pfeiffer syndrome: a link to midface hypoplasia.  

PubMed

The spheno-occipital synchondrosis (SOS) is a critical component of midfacial and cranial base growth. Premature closure has been associated with midface hypoplasia in animal models and syndromic craniosynostosis subpopulations with Apert and Muenke syndromes. To link premature SOS closure and midface hypoplasia in patients with Pfeiffer syndrome, a retrospective case-control study was performed in patients treated at a large craniofacial center between 1982 and 2012 diagnosed with Pfeiffer syndrome. At least 1 computed tomography (CT) scan was required to assess SOS patency. Age-/sex-matched control CT scans were also assessed for SOS patency. Three independent reviewers with high interrater reliability (? = 0.88) graded SOS patency as open, partially closed, or completely closed. Wilcoxon rank sum test compared the Pfeiffer patients with control subjects. A total of 63 CT scans in 16 patients with Pfeiffer syndrome, all with midface hypoplasia, and 63 age-/sex-matched control scans, none of whom had midface hypoplasia, met inclusion criteria. Earliest partial SOS closure in patients with Pfeiffer syndrome was seen at 5 days compared with control subjects at 7.07 years. Earliest age at complete fusion was 2.76 years in the Pfeiffer cohort and 12.74 years in control subjects. Average age at partial closure was significantly younger (4.99 ± 3.33 years; n = 31 scans) in patients with Pfeiffer syndrome compared with control subjects (10.92 ± 3.53 years) (P = 0.0005), whereas average age at complete closure (11.90 ± 7.04 years) was not significantly different than that in control subjects (16.07 ± 3.39 years). Although definitive causality cannot be concluded, a strong correlation exists between midface hypoplasia and premature SOS closure in Pfeiffer syndrome. PMID:24406578

Paliga, James Thomas; Goldstein, Jesse A; Vossough, Arastoo; Bartlett, Scott P; Taylor, Jesse Adam

2014-01-01

272

Flood risk analysis and adaptive strategy in context of uncertainties: a case study of Nhieu Loc Thi Nghe Basin, Ho Chi Minh City  

NASA Astrophysics Data System (ADS)

The Nhieu Loc - Thi Nghe basin is the most important administrative and business area of Ho Chi Minh City. Due to system complexity of the basin such as the increasing trend of rainfall intensity, (tidal) water level and land subsidence, the simulation of hydrological, hydraulic variables for flooding prediction seems rather not adequate in practical projects. The basin is still highly vulnerable despite of multi-million USD investment for urban drainage improvement projects since the last decade. In this paper, an integrated system analysis in both spatial and temporal aspects based on statistical, GIS and modelling approaches has been conducted in order to: (1) Analyse risks before and after projects, (2) Foresee water-related risk under uncertainties of unfavourable driving factors and (3) Develop a sustainable flood risk management strategy for the basin. The results show that given the framework of risk analysis and adaptive strategy, certain urban developing plans in the basin must be carefully revised and/or checked in order to reduce the highly unexpected loss in the future

Ho, Long-Phi; Chau, Nguyen-Xuan-Quang; Nguyen, Hong-Quan

2013-04-01

273

Increased Amygdala and Visual Cortex Activity and Functional Connectivity towards Stimulus Novelty Is Associated with State Anxiety  

PubMed Central

Novel stimuli often require a rapid reallocation of sensory processing resources to determine the significance of the event, and the appropriate behavioral response. Both the amygdala and the visual cortex are central elements of the neural circuitry responding to novelty, demonstrating increased activity to new as compared to highly familiarized stimuli. Further, these brain areas are intimately connected, and thus the amygdala may be a key region for directing sensory processing resources to novel events. Although knowledge regarding the neurocircuit of novelty detection is gradually increasing, we still lack a basic understanding of the conditions that are necessary and sufficient for novelty-specific responses in human amygdala and the visual cortices, and if these brain areas interact during detection of novelty. In the present study, we investigated the response of amygdala and the visual cortex to novelty, by comparing functional MRI activity between 1st and 2nd time presentation of a series of emotional faces in an event-related task. We observed a significant decrease in amygdala and visual cortex activity already after a single stimulus exposure. Interestingly, this decrease in responsiveness was less for subjects with a high score on state anxiety. Further, novel faces stimuli were associated with a relative increase in the functional coupling between the amygdala and the inferior occipital gyrus (BA 18). Thus, we suggest that amygdala is involved in fast sensory boosting that may be important for attention reallocation to novel events, and that the strength of this response depends on individual state anxiety. PMID:24755617

Ousdal, Olga T.; Andreassen, Ole A.; Server, Andres; Jensen, Jimmy

2014-01-01

274

A model of cerebral cortex formation during fetal development using reaction-diffusion-convection equations with Turing space parameters.  

PubMed

The cerebral cortex is a gray lamina formed by bodies of neurons covering the cerebral hemispheres, varying in thickness from 1.25 mm in the occipital lobe to 4mm in the anterior lobe. The brain's surface is about 30 times greater that of the skull because of its many folds; such folds form the gyri, sulci and fissures and mark out areas having specific functions, divided into five lobes. Convolution formation may vary between individuals and is an important feature of brain formation; such patterns can be mathematically represented as Turing patterns. This article describes how a phenomenological model was developed by describing the formation pattern for the gyri occurring in the cerebral cortex by reaction diffusion equations with Turing space parameters. Numerical examples for simplified geometries of a brain were solved to study pattern formation. The finite element method was used for the numerical solution, in conjunction with the Newton-Raphson method. The numerical examples showed that the model can represent cerebral cortex fold formation and reproduce pathologies related to gyri formation, such as polymicrogyria and lissencephaly. PMID:21784547

Garzón-Alvarado, Diego Alexander; Martinez, Angelica Maria Ramirez; Segrera, Dorian Luis Linero

2011-12-01

275

Linkage to chromosome 2q36.1 in autosomal dominant Dandy-Walker malformation with occipital cephalocele and evidence for genetic heterogeneity  

Microsoft Academic Search

We previously reported a Vietnamese-American family with isolated autosomal dominant occipital cephalocele. Upon further neuroimaging\\u000a studies, we have recharacterized this condition as autosomal dominant Dandy-Walker with occipital cephalocele (ADDWOC). A\\u000a similar ADDWOC family from Brazil was also recently described. To determine the genetic etiology of ADDWOC, we performed genome-wide\\u000a linkage analysis on members of the Vietnamese-American and Brazilian pedigrees. Linkage

Ali Jalali; Kimberly A. Aldinger; Ajit Chary; David G. Mclone; Robin M. Bowman; Luan Cong Le; Phillip Jardine; Ruth Newbury-Ecob; Andrew Mallick; Nadereh Jafari; Eric J. Russell; John Curran; Pam Nguyen; Karim Ouahchi; Charles Lee; William B. Dobyns; Kathleen J. Millen; Joao M. Pina-Neto; John A. Kessler; Alexander G. Bassuk

2008-01-01

276

DARPP-32, a phosphoprotein enriched in dopaminoceptive neurons bearing dopamine D1 receptors: distribution in the cerebral cortex of the newborn and adult rhesus monkey.  

PubMed

DARPP-32, a dopamine (DA) and cAMP-regulated phosphoprotein, is associated with dopaminoceptive neurons bearing D-1 receptors in the basal ganglia. The present study addressed the distribution of DARPP-32 in the primate cerebral cortex and its putative association with D-1 receptor laden cells in this structure. DARPP-32-like immunoreactive (LIR) neurons were examined in the cerebral cortex of 3-day-old (P3), 6-week-old (P42), and adult rhesus monkeys. In the younger cases, a large number of DARPP-32 positive neurons, with the morphological characteristics of pyramidal cells, were observed throughout the cortex, in layers V-VI, and to a lesser extent in layer II and uppermost layer III. In the parietal, insular, temporal, and occipital cortices, DARPP-32 positive neurons were arranged in a monolayer in layer Va. They were often clustered in small groups with a bundling of their dendrites. In the primary motor cortex, Betz cells were among the labeled population. In the association and somatosensory areas, the basal dendrites of DARPP-32 positive neurons and the prominent tufting of their apical dendrites in layer I contributed to an essential bilaminar pattern resembling the distribution reported for DA afferents and D-1 receptors in these areas. The prominence and widespread distribution of DARPP-32 positive neurons in layer V may be a specialization of primate cortex since such cells are found only in restricted locations in rodents. The literature on the connections of the cerebral cortex suggests that a large number of the DARPP-32 positive neurons in layer VI and perhaps even in layer Va may be corticothalamic neurons. An important developmental observation was the presence of DARPP-32-LIR neurons in the white matter. They were prominent in the neonates but could not be seen in the adult. Their location as well as their type and shape were reminiscent of interstitial neurons. In the adult monkeys, the distribution of DARPP-32-LIR neurons was more circumscribed: they were numerous in the ventral temporal gyrus and in areas related to the limbic system: caudal orbitofrontal cortex, insula, temporal pole, entorhinal, and anterior cingulate cortex. Weak labeling was detected in layer Va of the superior temporal and parietal cortex, in some prefrontal areas (10, 13, and medial 9), and in the premotor and supplementary motor cortex; in adults, unlike neonates, few DARPP-32-LIR neurons were present in the dorsolateral prefrontal cortex, the primary motor or the primary visual or prestriate cortices.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:2229482

Berger, B; Febvret, A; Greengard, P; Goldman-Rakic, P S

1990-09-15

277

Abnormal Anatomical Connectivity between the Amygdala and Orbitofrontal Cortex in Conduct Disorder  

PubMed Central

Objective Previous research suggested that structural and functional abnormalities within the amygdala and orbitofrontal cortex contribute to the pathophysiology of Conduct Disorder (CD). Here, we investigated whether the integrity of the white-matter pathways connecting these regions is abnormal and thus may represent a putative neurobiological marker for CD. Methods Diffusion Tensor Imaging (DTI) was used to investigate white-matter microstructural integrity in male adolescents with childhood-onset CD, compared with healthy controls matched in age, sex, intelligence, and socioeconomic status. Two approaches were employed to analyze DTI data: voxel-based morphometry of fractional anisotropy (FA), an index of white-matter integrity, and virtual dissection of white-matter pathways using tractography. Results Adolescents with CD displayed higher FA within the right external capsule relative to controls (T?=?6.08, P<0.05, Family-Wise Error, whole-brain correction). Tractography analyses showed that FA values within the uncinate fascicle (connecting the amygdala and orbitofrontal cortex) were abnormally increased in individuals with CD relative to controls. This was in contrast with the inferior frontal-occipital fascicle, which showed no significant group differences in FA. The finding of increased FA in the uncinate fascicle remained significant when factoring out the contribution of attention-deficit/hyperactivity disorder symptoms. There were no group differences in the number of streamlines in either of these anatomical tracts. Conclusions These results provide evidence that CD is associated with white-matter microstructural abnormalities in the anatomical tract that connects the amygdala and orbitofrontal cortex, the uncinate fascicle. These results implicate abnormal maturation of white-matter pathways which are fundamental in the regulation of emotional behavior in CD. PMID:23144970

Passamonti, Luca; Fairchild, Graeme; Fornito, Alex; Goodyer, Ian M.; Nimmo-Smith, Ian; Hagan, Cindy C.; Calder, Andrew J.

2012-01-01

278

The selective role of premotor cortex in speech perception: a contribution to phoneme judgements but not speech comprehension.  

PubMed

Several accounts of speech perception propose that the areas involved in producing language are also involved in perceiving it. In line with this view, neuroimaging studies show activation of premotor cortex (PMC) during phoneme judgment tasks; however, there is debate about whether speech perception necessarily involves motor processes, across all task contexts, or whether the contribution of PMC is restricted to tasks requiring explicit phoneme awareness. Some aspects of speech processing, such as mapping sounds onto meaning, may proceed without the involvement of motor speech areas if PMC specifically contributes to the manipulation and categorical perception of phonemes. We applied TMS to three sites-PMC, posterior superior temporal gyrus, and occipital pole-and for the first time within the TMS literature, directly contrasted two speech perception tasks that required explicit phoneme decisions and mapping of speech sounds onto semantic categories, respectively. TMS to PMC disrupted explicit phonological judgments but not access to meaning for the same speech stimuli. TMS to two further sites confirmed that this pattern was site specific and did not reflect a generic difference in the susceptibility of our experimental tasks to TMS: stimulation of pSTG, a site involved in auditory processing, disrupted performance in both language tasks, whereas stimulation of occipital pole had no effect on performance in either task. These findings demonstrate that, although PMC is important for explicit phonological judgments, crucially, PMC is not necessary for mapping speech onto meanings. PMID:23937689

Krieger-Redwood, Katya; Gaskell, M Gareth; Lindsay, Shane; Jefferies, Elizabeth

2013-12-01

279

Attention: control in the visual cortex.  

PubMed

A recent study in which the human visual cortex was directly stimulated to create visual percepts has shown that visual spatial attention can act directly on neural activity in sensory cortex without involving attentional modulation of subcortical visual inputs. PMID:17339016

Mangun, George R; Fannon, Sean P

2007-03-01

280

Functional Organization of Ferret Auditory Cortex  

Microsoft Academic Search

We characterized the functional organization of different fields within the auditory cortex of anaesthetized ferrets. As previously reported, the primary auditory cortex, A1, and the anterior auditory field, AAF, are located on the middle ectosylvian gyrus. These areas exhibited a similar tonotopic organization, with high frequencies represented at the dorsal tip of the gyrus and low frequencies more ventrally, but

Jennifer K. Bizley; Fernando R. Nodal; Israel Nelken; Andrew J. King

2005-01-01

281

Divergent Plasticity of Prefrontal Cortex Networks  

Microsoft Academic Search

The ‘executive’ regions of the prefrontal cortex (PFC) such as the dorsolateral PFC (dlPFC) and its rodent equivalent medial PFC (mPFC) are thought to respond in concert with the ‘limbic’ regions of the PFC such as the orbitofrontal (OFC) cortex to orchestrate behavior that is consistent with context and expected outcome. Both groups of regions have been implicated in behavioral

Bita Moghaddam; Houman Homayoun

2008-01-01

282

Attention modulates spatial priority maps in the human occipital, parietal and frontal cortices  

PubMed Central

Computational theories propose that attention modulates the topographical landscape of spatial ‘priority’ maps in regions of visual cortex so that the location of an important object is associated with higher activation levels. While single-unit recording studies have demonstrated attention-related increases in the gain of neural responses and changes in the size of spatial receptive fields, the net effect of these modulations on the topography of region-level priority maps has not been investigated. Here, we used fMRI and a multivariate encoding model to reconstruct spatial representations of attended and ignored stimuli using activation patterns across entire visual areas. These reconstructed spatial representations reveal the influence of attention on the amplitude and size of stimulus representations within putative priority maps across the visual hierarchy. Our results suggest that attention increases the amplitude of stimulus representations in these spatial maps, particularly in higher visual areas, but does not substantively change their size. PMID:24212672

Sprague, Thomas C.; Serences, John T.

2014-01-01

283

Investigating Representations of Facial Identity in Human Ventral Visual Cortex with Transcranial Magnetic Stimulation  

PubMed Central

The occipital face area (OFA) is face-selective. This enhanced activation to faces could reflect either generic face and shape-related processing or high-level conceptual processing of identity. Here we examined these two possibilities using a state-dependent transcranial magnetic stimulation (TMS) paradigm. The lateral occipital (LO) cortex which is activated non-selectively by various types of objects served as a control site. We localized OFA and LO on a per-participant basis using functional MRI. We then examined whether TMS applied to either of these regions affected the ability of participants to decide whether two successively presented and physically different face images were of the same famous person or different famous people. TMS was applied during the delay between first and second face presentations to investigate whether neuronal populations in these regions played a causal role in mediating the behavioral effects of identity repetition. Behaviorally we found a robust identity repetition effect, with shorter reaction times (RTs) when identity was repeated, regardless of the fact that the pictures were physically different. Surprisingly, TMS applied over LO (but not OFA) modulated overall RTs, compared to the No-TMS condition. But critically, we found no effects of TMS to either area that were modulated by identity repetition. Thus, we found no evidence to suggest that OFA or LO contain neuronal representations selective for the identity of famous faces which play a causal role in identity processing. Instead, these brain regions may be involved in the processing of more generic features of their preferred stimulus categories. PMID:20631842

Gilaie-Dotan, Sharon; Silvanto, Juha; Schwarzkopf, Dietrich S.; Rees, Geraint

2010-01-01

284

Casagrande, V.A. and J.H. Kaas The afferent, intrinsic, and efferent of visual cortex primates. In: Cerebral Cortex, 10, Primary VisualCortex A. Peters  

E-print Network

: Cerebral Cortex, 10, Primary VisualCortex A. Peters and K. Rockland, Eds. Plenum Press, N.Y., pp. 201, Vanderbilt Univer- sity, Nashville, Tennessee 37232. Cerebral Cortex, Volume 10, edited by Alan PetersCasagrande, V.A. and J.H. Kaas The afferent, intrinsic, and efferent of visual cortex primates. In

Casagrande, Vivien

285

Addiction and the adrenal cortex  

PubMed Central

Substantial evidence shows that the hypophyseal–pituitary–adrenal (HPA) axis and corticosteroids are involved in the process of addiction to a variety of agents, and the adrenal cortex has a key role. In general, plasma concentrations of cortisol (or corticosterone in rats or mice) increase on drug withdrawal in a manner that suggests correlation with the behavioural and symptomatic sequelae both in man and in experimental animals. Corticosteroid levels fall back to normal values in resumption of drug intake. The possible interactions between brain corticotrophin releasing hormone (CRH) and proopiomelanocortin (POMC) products and the systemic HPA, and additionally with the local CRH–POMC system in the adrenal gland itself, are complex. Nevertheless, the evidence increasingly suggests that all may be interlinked and that CRH in the brain and brain POMC products interact with the blood-borne HPA directly or indirectly. Corticosteroids themselves are known to affect mood profoundly and may themselves be addictive. Additionally, there is a heightened susceptibility for addicted subjects to relapse in conditions that are associated with change in HPA activity, such as in stress, or at different times of the day. Recent studies give compelling evidence that a significant part of the array of addictive symptoms is directly attributable to the secretory activity of the adrenal cortex and the actions of corticosteroids. Additionally, sex differences in addiction may also be attributable to adrenocortical function: in humans, males may be protected through higher secretion of DHEA (and DHEAS), and in rats, females may be more susceptible because of higher corticosterone secretion. PMID:23825159

Vinson, Gavin P; Brennan, Caroline H

2013-01-01

286

Sensory-specific anomic aphasia following left occipital lesions: Data from free oral descriptions of concrete word meanings  

PubMed Central

The present study investigated hierarchical lexical semantic structure in oral descriptions of concrete word meanings produced by a subject (ZZ) diagnosed with anomic aphasia due to left occipital lesions. The focus of the analysis was production of a) nouns at different levels of semantic specificity (e.g., “robin”–“bird”–“animal”) and b) words describing sensory or motor experiences (e.g., “blue,” “soft,” “fly”). Results show that in contrast to healthy and aphasic controls, who produced words at all levels of specificity and mainly vision-related sensory information, ZZ produced almost exclusively nouns at the most non-specific levels and words associated with sound and movement. PMID:23425233

Martensson, F.; Roll, M.; Lindgren, M.; Apt, P.; Horne, M.

2013-01-01

287

Medial perirhinal cortex disambiguates confusable objects  

PubMed Central

Our brain disambiguates the objects in our cluttered visual world seemingly effortlessly, enabling us to understand their significance and to act appropriately. The role of anteromedial temporal structures in this process, particularly the perirhinal cortex, is highly controversial. In some accounts, the perirhinal cortex is necessary for differentiating between perceptually and semantically confusable objects. Other models claim that the perirhinal cortex neither disambiguates perceptually confusable objects nor plays a unique role in semantic processing. One major hurdle to resolving this central debate is the fact that brain damage in human patients typically encompasses large portions of the anteromedial temporal lobe, such that the identification of individual substructures and precise neuroanatomical locus of the functional impairments has been difficult. We tested these competing accounts in patients with Alzheimer’s disease with varying degrees of atrophy in anteromedial structures, including the perirhinal cortex. To assess the functional contribution of each anteromedial temporal region separately, we used a detailed region of interest approach. From each participant, we obtained magnetic resonance imaging scans and behavioural data from a picture naming task that contrasted naming performance with living and non-living things as a way of manipulating perceptual and semantic confusability; living things are more similar to one another than non-living things, which have more distinctive features. We manually traced neuroanatomical regions of interest on native-space cortical surface reconstructions to obtain mean thickness estimates for the lateral and medial perirhinal cortex and entorhinal cortex. Mean cortical thickness in each region of interest, and hippocampal volume, were submitted to regression analyses predicting naming performance. Importantly, atrophy of the medial perirhinal cortex, but not lateral perirhinal cortex, entorhinal cortex or hippocampus, significantly predicted naming performance on living relative to non-living things. These findings indicate that one specific anteromedial temporal lobe region—the medial perirhinal cortex—is necessary for the disambiguation of perceptually and semantically confusable objects. Taken together, these results support a hierarchical account of object processing, whereby the perirhinal cortex at the apex of the ventral object processing system is required to bind properties of not just perceptually, but also semantically confusable objects together, enabling their disambiguation from other similar objects and thus comprehension. Significantly, this model combining a hierarchical object processing architecture with a semantic feature statistic account explains why category-specific semantic impairments for living things are associated with anteromedial temporal lobe damage, and pinpoints the root of this syndrome to perirhinal cortex damage. PMID:23250887

Tyler, Lorraine K.; Monsch, Andreas U.; Taylor, Kirsten I.

2012-01-01

288

Cerebral Cortex doi:10.1093/cercor/bhp121  

E-print Network

, either due to lesion or aging (as well as children, in whom the frontal lobe has not yet fully developed and occipital regions were found to increase activity when multiple relations had to be integrated in order

Poldrack, Russ

289

Multiple EDAS (encephalo-duro-arterio-synangiosis)Additional EDAS using the frontal branch of the superficial temporal artery (STA) and the occipital artery for pediatric moyamoya patients in whom EDAS using the parietal branch of STA was insufficient  

Microsoft Academic Search

Although parietal EDAS or STA-MCA anastomosis are effective in pediatric moyamoya disease, they do not adequately prevent\\u000a ischemia in the frontal and occipital lobes. Some additional methods that can prevent ischemia in the frontal and occipital\\u000a lobes are sometimes needed. We investigated whether EDAS using a frontal branch of the superficial temporal artery (frontal\\u000a EDAS) or EDAS using the occipital

Hiroshi Tenjin; Satoshi Ueda

1997-01-01

290

Decreased white matter integrity in fronto-occipital fasciculus bundles: relation to visual information processing in alcohol-dependent subjects.  

PubMed

Chronic alcohol abuse is characterized by impaired cognitive abilities with a more severe deficit in visual than in verbal functions. Neuropathologically, it is associated with widespread brain structural compromise marked by gray matter shrinkage, ventricular enlargement, and white matter degradation. The present study sought to increase current understanding of the impairment of visual processing abilities in alcohol-dependent subjects, and its correlation with white matter microstructural alterations, using diffusion tensor imaging (DTI). To that end, a DTI study was carried out on 35 alcohol-dependent subjects and 30 healthy male control subjects. Neuropsychological tests were assessed for visual processing skills and deficits were reported as raw dysfunction scores (rDyS). Reduced FA (fractional anisotropy) and increased MD (mean diffusivity) were observed bilaterally in inferior and superior fronto-occipital fasciculus (FOF) fiber bundles. A significant inverse correlation in rDyS and FA values was observed in these fiber tracts whereas a positive correlation of these scores was found with the MD values. Our results suggest that FOF fiber bundles linking the frontal lobe to occipital lobe might be related to visual processing skills. This is the first report of an alteration of the white matter microstructure of FOF fiber bundles that might have functional consequences for visual processing in alcohol-dependent subjects who exhibit no neurological complications. PMID:24388377

Bagga, Deepika; Sharma, Aakansha; Kumari, Archana; Kaur, Prabhjot; Bhattacharya, Debajyoti; Garg, Mohan Lal; Khushu, Subash; Singh, Namita

2014-02-01

291

Elastic instabilities in a layered cerebral cortex: A revised axonal tension model for cortex folding  

E-print Network

We model the viscoelasticity of the cerebral cortex as a layered material with bending energy along the layers and elastic energy between them in both planar and polar geometries. The cortex is also subjected to axons pulling from the underlying white matter. Above a critical threshold force, a "flat" cortex configuration becomes unstable and periodic unduluations emerge, i.e. a buckling instability occurs. These undulations may indeed initiate folds in the cortex. We identify analytically the critical force and the critical wavelength of the undulations. Both quantities are physiologically relevant values. Our model is a revised version of the axonal tension model for cortex folding, with the initial version invoking circumferential axon pulling, which is not necessarily in keeping with observations. Moreover, our model draws a connection with another competing model for cortex folding, namely the differential growth-induced buckling model. For the polar geometry, we study the relationship between brain size...

Manyuhina, O V; Schwarz, J M

2014-01-01

292

Surface-Based and Probabilistic Atlases of Primate Cerebral Cortex  

E-print Network

Neuron Primer Surface-Based and Probabilistic Atlases of Primate Cerebral Cortex David C. Van Essen. For studies of cerebral cortex there is particular utility in hybrid atlases that capitalize focuses on surface-based atlases of cerebral cortex in primates, especially humans. Cerebral cortex

Van Essen, David

293

Prefrontal Cortex Activity during Flexible Categorization  

E-print Network

Items are categorized differently depending on the behavioral context. For instance, a lion can be categorized as an African animal or a type of cat. We recorded lateral prefrontal cortex (PFC) neural activity while monkeys ...

Roy, Jefferson

294

Suppression without inhibition in visual cortex.  

PubMed

Neurons in primary visual cortex (V1) are thought to receive inhibition from other V1 neurons selective for a variety of orientations. Evidence for this inhibition is commonly found in cross-orientation suppression: responses of a V1 neuron to optimally oriented bars are suppressed by superimposed mask bars of different orientation. We show, however, that suppression is unlikely to result from intracortical inhibition. First, suppression can be obtained with masks drifting too rapidly to elicit much of a response in cortex. Second, suppression is immune to hyperpolarization (through visual adaptation) of cortical neurons responding to the mask. Signals mediating suppression might originate in thalamus, rather than in cortex. Thalamic neurons exhibit some suppression; additional suppression might arise from depression at thalamocortical synapses. The mechanisms of suppression are subcortical and possibly include the very first synapse into cortex. PMID:12194874

Freeman, Tobe C B; Durand, Séverine; Kiper, Daniel C; Carandini, Matteo

2002-08-15

295

Decreased entorhinal cortex volumes in schizophrenia  

Microsoft Academic Search

BackgroundThe entorhinal cortex is located in the medial temporal lobe and is involved in memory and learning. Previous MRI studies reported conflicting findings in schizophrenia, showing normal or reduced entorhinal size.

Monica Baiano; Cinzia Perlini; Gianluca Rambaldelli; Roberto Cerini; Nicola Dusi; Marcella Bellani; Giorgia Spezzapria; Amelia Versace; Matteo Balestrieri; Roberto Pozzi Mucelli; Michele Tansella; Paolo Brambilla

2008-01-01

296

Layered Network Model of Sensory Cortex.  

National Technical Information Service (NTIS)

An integrated computational approach to modeling sensory systems which couples realistic layered neural models of sensory cortex and midbrain nuclei to detailed models of the sense organs (e.g., retina or cochlea) is described. The approach is applied to ...

B. J. Travis

1986-01-01

297

Multisensory maps in parietal cortex?  

PubMed Central

Parietal cortex has long been known to be a site of sensorimotor integration. Recent findings in humans have shown that it is divided up into a number of small areas somewhat specialized for eye movements, reaching, and hand movements, but also face-related movements (avoidance, eating), lower body movements, and movements coordinating multiple body parts. The majority of these areas contain rough sensory (receptotopic) maps, including a substantial multisensory representation of the lower body and lower visual field immediately medial to face VIP. There is strong evidence for retinotopic remapping in LIP and face-centered remapping in VIP, and weaker evidence for hand-centered remapping. The larger size of the functionally distinct inferior parietal default mode network in humans compared to monkeys results in a superior and medial displacement of middle parietal areas (e.g., the saccade-related LIP's). Multisensory superior parietal areas located anterior to the angular gyrus such as AIP and VIP are less medially displaced relative to macaque monkeys, so that human LIP paradoxically ends up medial to human VIP. PMID:24492077

Sereno, Martin I; Huang, Ruey-Song

2014-01-01

298

Redundancy gains in retinotopic cortex  

PubMed Central

It is widely claimed that interactions among simultaneously presented visual stimuli are suppressive and that these interactions primarily occur when stimuli fall within the same receptive field (Desimone and Duncan 1995). Here, we show evidence for a novel form of interaction between simultaneously presented but distant stimuli that does not fit either pattern. To examine interactions between simultaneously presented stimuli, we measure the response to a single stimulus as a function of whether or not other stimuli are also presented simultaneously, and we further ask how the response to a given stimulus is affected by whether the simultaneously present stimuli are identical or different from each other. Our method reveals a new phenomenon of “redundancy gain:” the visual response to a stimulus is higher when accompanied by identical stimuli than when that stimulus is presented alone, even though the stimuli are displayed in separate visual quadrants. This pattern is observed throughout the visual hierarchy, including V1 and V2, and we show that it is distinct from the well-known simultaneous suppression effect (Kastner et al. 1998). We propose that the redundancy gain in early retinotopic cortex results from feedback from higher visual areas and may underlie perceptual averaging and other ensemble coding phenomena observed behaviorally. PMID:23904496

Jiang, Yuhong V.; Kanwisher, Nancy

2013-01-01

299

Variations in ncRNA gene LOC284889 and MIF-794CATT repeats are associated with malaria susceptibility in Indian populations  

PubMed Central

Background There are increasing evidences on the role of non-coding RNA (ncRNA) as key regulator of cellular homeostasis. LOC284889 is an uncharacterized ncRNA gene on reverse strand to MIF mapped to 22q11.23. MIF, a lymphokine, regulates innate immune response by up-regulating the expression of TLR4, suppressing the p53 activity and has been shown to be involved in malaria pathogenesis. Methods In this study, the possible effect of MIF variations on malaria susceptibility was investigated by re-sequencing the complete MIF gene along with 1 kb each of 5? and 3? region in 425 individuals from malaria endemic regions of the Orissa and Chhattisgarh states of India. The subjects comprised of 160 cases of severe malaria, 101 of mild malaria and 164 ethnically matched asymptomatic controls. Data were statistically compared between cases and controls for their possible association with Plasmodium falciparum malarial outcome. Results It is the first study, which shows that the allele A (rs34383331T?>?A) in ncRNA is significantly associated with increased risk to P. falciparum malaria [severe: OR?=?2.08, p?=?0.002 and mild: OR?=?2.09, P?=?0.005]. In addition, it has been observed that the higher MIF-794CATT repeats (>5) increases malaria risk (OR?=?1.61, p?=?0.01). Further, diplotype (MIF-794CATT and rs34383331T?>?A) 5 T confers protection to severe malaria (OR?=?0.55, p?=?0.002) while 6A (OR?=?3.07, p?=?0.001) increases malaria risk. Conclusions These findings support the involvement of ncRNA in malarial pathogenesis and further emphasize the complex genetic regulation of malaria outcome. In addition, the study shows that the higher MIF-794CATT repeats (>5) is a risk factor for severe malaria. The study would help in identifying people who are at higher risk to malaria and adapt strategies for prevention and treatment. PMID:24066864

2013-01-01

300

Behavioral planning in the prefrontal cortex  

Microsoft Academic Search

Recent studies have presented evidence that the prefrontal cortex plays a crucial role in every aspect of the cognitive processes necessary for behavioral planning: processing and integration of perceived or memorized information, associative learning, reward-based behavioral control, behavioral selection\\/decision-making and behavioral guidance. We propose that the creation of novel information is the means by which the prefrontal cortex operates to

Jun Tanji; Eiji Hoshi

2001-01-01

301

Premotor cortex mediates perceptual performance.  

PubMed

Articulatory goals have long been proposed to mediate perception. Examples include direct realist and constructivist (analysis by synthesis) theories of speech perception. Although the activity in brain regions involved with action production has been shown to be present during action observation (Mirror Neuron System), the relationship of this activity to perceptual performance has not been clearly demonstrated at the event level. To this end we used functional magnetic resonance imaging fMRI and magnetoencephalography MEG to measure brain activity for correct and incorrect trials of an auditory phonetic identification in noise task. FMRI analysis revealed activity in the premotor cortex including the neighboring frontal opercular part of Broca's area (PMC/Broca's) for both perception and production tasks involving the same phonetic stimuli (potential mirror system site) that was significantly greater for correct over incorrect perceptual identification trials. Time-frequency analysis of single trials conducted over MEG current localized to PMC/Broca's using a hierarchical variational Bayesian source analysis technique revealed significantly greater event-related synchronization ERS and desynchronization ERD for correct over incorrect trials in the alpha, beta, and gamma frequency range prior to and after stimulus presentation. Together, these fMRI and MEG results are consistent with the hypothesis that articulatory processes serve to facilitate perceptual performance, while further dispelling concerns that activity found in ventral PMC/Broca's (mirror system) is merely a product of covert production of the perceived action. The finding of performance predictive activity prior to stimulus onset as well as activity related to task difficulty instead of information available in stimulation are consistent with constructivist and contrary to direct realist theories of perception. PMID:20184959

Callan, Daniel; Callan, Akiko; Gamez, Mario; Sato, Masa-aki; Kawato, Mitsuo

2010-06-01

302

Single-trial discrimination for integrating simultaneous EEG and fMRI: Identifying cortical areas contributing to trial-to-trial variability in the auditory oddball task  

E-print Network

Max Planck Institute for Human Development, Neurocognition of Decision Making Group, Lentzeallee 94 is the strong activation of the lateral occipital complex (LOC). The LOC was not seen when using traditional

Sajda, Paul

303

Training Transfers the Limits on Perception from Parietal to Ventral Cortex  

PubMed Central

Summary Visually guided behavior depends on (1) extracting and (2) discriminating signals from complex retinal inputs, and these perceptual skills improve with practice [1]. For instance, training on aerial reconnaissance facilitated World War II Allied military operations [2]; analysts pored over stereoscopic photographs, becoming expert at (1) segmenting pictures into meaningful items to break camouflage from (noisy) backgrounds, and (2) discriminating fine details to distinguish V-weapons from innocuous pylons. Training is understood to optimize neural circuits that process scene features (e.g., orientation) for particular purposes (e.g., judging position) [3–6]. Yet learning is most beneficial when it generalizes to other settings [7, 8] and is critical in recovery after adversity [9], challenging understanding of the circuitry involved. Here we used repetitive transcranial magnetic stimulation (rTMS) to infer the functional organization supporting learning generalization in the human brain. First, we show dissociable contributions of the posterior parietal cortex (PPC) versus lateral occipital (LO) circuits: extracting targets from noise is disrupted by PPC stimulation, in contrast to judging feature differences, which is affected by LO rTMS. Then, we demonstrate that training causes striking changes in this circuit: after feature training, identifying a target in noise is not disrupted by PPC stimulation but instead by LO stimulation. This indicates that training shifts the limits on perception from parietal to ventral brain regions and identifies a critical neural circuit for visual learning. We suggest that generalization is implemented by supplanting dynamic processing conducted in the PPC with specific feature templates stored in the ventral cortex. PMID:25283780

Chang, Dorita H.F.; Mevorach, Carmel; Kourtzi, Zoe; Welchman, Andrew E.

2014-01-01

304

The cerebral cortex of Albert Einstein: a description and preliminary analysis of unpublished photographs  

PubMed Central

Upon his death in 1955, Albert Einstein’s brain was removed, fixed and photographed from multiple angles. It was then sectioned into 240 blocks, and histological slides were prepared. At the time, a roadmap was drawn that illustrates the location within the brain of each block and its associated slides. Here we describe the external gross neuroanatomy of Einstein’s entire cerebral cortex from 14 recently discovered photographs, most of which were taken from unconventional angles. Two of the photographs reveal sulcal patterns of the medial surfaces of the hemispheres, and another shows the neuroanatomy of the right (exposed) insula. Most of Einstein’s sulci are identified, and sulcal patterns in various parts of the brain are compared with those of 85 human brains that have been described in the literature. To the extent currently possible, unusual features of Einstein’s brain are tentatively interpreted in light of what is known about the evolution of higher cognitive processes in humans. As an aid to future investigators, these (and other) features are correlated with blocks on the roadmap (and therefore histological slides). Einstein’s brain has an extraordinary prefrontal cortex, which may have contributed to the neurological substrates for some of his remarkable cognitive abilities. The primary somatosensory and motor cortices near the regions that typically represent face and tongue are greatly expanded in the left hemisphere. Einstein’s parietal lobes are also unusual and may have provided some of the neurological underpinnings for his visuospatial and mathematical skills, as others have hypothesized. Einstein’s brain has typical frontal and occipital shape asymmetries (petalias) and grossly asymmetrical inferior and superior parietal lobules. Contrary to the literature, Einstein’s brain is not spherical, does not lack parietal opercula and has non-confluent Sylvian and inferior postcentral sulci. PMID:23161163

Lepore, Frederick E.; Noe, Adrianne

2013-01-01

305

Clutter modulates the representation of target objects in the human occipitotemporal cortex.  

PubMed

Target objects required for goal-directed behavior are typically embedded within multiple irrelevant objects that may interfere with their encoding. Most neuroimaging studies of high-level visual cortex have examined the representation of isolated objects, and therefore, little is known about how surrounding objects influence the neural representation of target objects. To investigate the effect of different types of clutter on the distributed responses to target objects in high-level visual areas, we used fMRI and manipulated the type of clutter. Specifically, target objects (i.e., a face and a house) were presented either in isolation, in the presence of a homogeneous (identical objects from another category) clutter ("pop-out" display), or in the presence of a heterogeneous (different objects) clutter, while participants performed a target identification task. Using multivoxel pattern analysis (MVPA) we found that in the posterior fusiform object area a heterogeneous but not homogeneous clutter interfered with decoding of the target objects. Furthermore, multivoxel patterns evoked by isolated objects were more similar to multivoxel patterns evoked by homogenous compared with heterogeneous clutter in the lateral occipital and posterior fusiform object areas. Interestingly, there was no effect of clutter on the neural representation of the target objects in their category-selective areas, such as the fusiform face area and the parahippocampal place area. Our findings show that the variation among irrelevant surrounding objects influences the neural representation of target objects in the object general area, but not in object category-selective cortex, where the representation of target objects is invariant to their surroundings. PMID:24144245

Erez, Yaara; Yovel, Galit

2014-03-01

306

Prenatal diagnosis of occipital encephalocele, mega-cisterna magna, mesomelic shortening, and clubfeet associated with pure tetrasomy 20p.  

PubMed

We present the first case of a fetus with pure tetrasomy 20p proven by cord-blood sampling at 24 weeks of gestation. This case was diagnosed in utero with multiple congenital anomalies including occipital encephalocele, mega-cisterna magna, mesomelic shortening, and clubfeet. An analysis of GTG-banded chromosomes of 20 metaphase cells was performed. Female karyotype [47,XX, +i(20)(p10)] was revealed in all cells. Pure tetrasomy 20p was confirmed using fluorescent in situ hybridization (FISH) with a telomere probe for chromosome 20p in all seven metaphase cells. The pregnancy was terminated because of associated multiple anomalies and severe oligohydramnios. The postmortem examination confirmed the prenatal diagnosis. PMID:12575018

Wu, Yi-Cheng; Fang, Jye Siung; Lee, Kuei-Fang; Estipona, Judy; Yang, Man-Li; Yuan, Chiou-Chung

2003-02-01

307

Parathyroid adenoma diagnosed on the basis of a giant cell tumor of parieto-occipital region and multifocal bone injuries.  

PubMed

Brown tumors are rare skeletal manifestations of hyperparathyroidism (HPT) that may mimic cancer metastases. Histopathologically, they are difficult to differentiate from other giant cell lesions. A case is presented of 41-year-old woman with giant cell tumor in parieto-occipital region with injury of external bone lamina, growing into the skull cavity. The mass was suspected of being neoplastic. Numerous osteolytic lesions in the skull skeleton and multifocal bone injuries were observed, also. Elevation in calcium (5.91 mEq/L) and parathormone (1188 ng/mL) concentrations and hypercalciuria (52 mEq/24 h) suggested the diagnosis of HPT initially manifesting as a brown tumor of the skull. Further exploration confirmed the existence of parathyroid adenoma as a cause of the disease. The key treatment for the condition was surgical excision of the adenoma followed by the normalization of parathyroid function and significant reduction in size of skull tumor and other lesions. PMID:24464010

Bohdanowicz-Pawlak, Anna; Szymczak, Jadwiga; Jakubowska, Joanna; Jedrzejuk, Diana; Pawlak, Andrzej; Lukienczuk, Tadeusz; Bolanowski, Marek

2013-01-01

308

Maturation of Extinction Behavior in Infant Rats: Large-Scale Regional Interactions with Medial Prefrontal Cortex, Orbitofrontal Cortex, and Anterior Cingulate Cortex  

Microsoft Academic Search

The ability to express a behavior during the postnatal period may be related to developmental changes in the recruitment of particular neural systems. Here, we show that developmental changes in the functional interactions involving three cortical regions (the medial prefrontal cortex, orbitofrontal cortex, and anterior cingulate cortex) are associated with maturation of extinction behavior in infant rats. Postnatal day 17

Hemanth P. Nair; Jason D. Berndt; Douglas Barrett; F. Gonzalez-Lima

2001-01-01

309

Motor Cortex Neuroplasticity Following Brachial Plexus Transfer  

PubMed Central

In the past decade, research has demonstrated that cortical plasticity, once thought only to exist in the early stages of life, does indeed continue on into adulthood. Brain plasticity is now acknowledged as a core principle of brain function and describes the ability of the central nervous system to adapt and modify its structural organization and function as an adaptive response to functional demand. In this clinical case study we describe how we used neuroimaging techniques to observe the functional topographical expansion of a patch of cortex along the sensorimotor cortex of a 27-year-old woman following brachial plexus transfer surgery to re-innervate her left arm. We found bilateral activations present in the thalamus, caudate, insula as well as across the sensorimotor cortex during an elbow flex motor task. In contrast we found less activity in the sensorimotor cortex for a finger tap motor task in addition to activations lateralized to the left inferior frontal gyrus and thalamus and bilaterally for the insula. From a pain perspective the patient who had experienced extensive phantom limb pain (PLP) before surgery found these sensations were markedly reduced following transfer of the right brachial plexus to the intact left arm. Within the context of this clinical case the results suggest that functional improvements in limb mobility are associated with increased activation in the sensorimotor cortex as well as reduced PLP. PMID:23966938

Dimou, Stefan; Biggs, Michael; Tonkin, Michael; Hickie, Ian B.; Lagopoulos, Jim

2013-01-01

310

Supplement to Vol. 19, 2000 ACTA ANTHROPOLOGICA SINICA 37-46 Thickness Mapping of the Occipital Bone on CT-data  

E-print Network

Bone on CT-data ­- a New Approach Applied on OH 9 Gerhard W. WEBER1 , Johann KIM2 , Arnold NEUMAIER2 University College of Health Science, P.O. Box 65453, Dar-es Salaam, TANZANIA; 4. Dept. of Radiology II for the analysis of cranial bone thickness is introduced. The study focuses on the occipital bone of modern humans

Neumaier, Arnold

311

Sexual differentiation of mammalian frontal cortex  

SciTech Connect

The pattern of distribution of the progesterone binding sites was examined in selected nuclei of the brain of male and female rat. In female rats the frontal cortex resulted to be the region with the highest concentration of /sup 3/H R5020 biding sites. However, in male rats the same region showed very little progestin binding activity. When female rats were androgenized via neonatal exposure to testosterone, the progestin binding activity of the frontal cortex became similar to that observed in male rats. The present investigation indicates that sexual differentiation of the rat brain may include also brain regions not clearly involved in sex related functions like the frontal cortex. 30 references, 2 figures, 1 table.

Maggi, A.; Zucchi, I.

1987-03-23

312

The Age of Human Cerebral Cortex Neurons  

SciTech Connect

The traditional static view of the adult mammalian brain has been challenged by the realization of continuous generation of neurons from stem cells. Based mainly on studies in experimental animals, adult neurogenesis may contribute to recovery after brain insults and decreased neurogenesis has been implicated in the pathogenesis of neurological and psychiatric diseases in man. The extent of neurogenesis in the adult human brain has, however, been difficult to establish. We have taken advantage of the integration of {sup 14}C, generated by nuclear bomb tests during the Cold War, in DNA to establish the age of neurons in the major areas of the human cerebral cortex. Together with the analysis of the cortex from patients who received BrdU, which integrates in the DNA of dividing cells, our results demonstrate that whereas non-neuronal cells turn over, neurons in the human cerebral cortex are not generated postnatally at detectable levels, but are as old as the individual.

Bhardwaj, R D; Curtis, M A; Spalding, K L; Buchholz, B A; Fink, D; Bjork-Eriksson, T; Nordborg, C; Gage, F H; Druid, H; Eriksson, P S; Frisen, J

2006-04-06

313

Spatial updating in human parietal cortex  

NASA Technical Reports Server (NTRS)

Single neurons in monkey parietal cortex update visual information in conjunction with eye movements. This remapping of stimulus representations is thought to contribute to spatial constancy. We hypothesized that a similar process occurs in human parietal cortex and that we could visualize it with functional MRI. We scanned subjects during a task that involved remapping of visual signals across hemifields. We observed an initial response in the hemisphere contralateral to the visual stimulus, followed by a remapped response in the hemisphere ipsilateral to the stimulus. We ruled out the possibility that this remapped response resulted from either eye movements or visual stimuli alone. Our results demonstrate that updating of visual information occurs in human parietal cortex.

Merriam, Elisha P.; Genovese, Christopher R.; Colby, Carol L.

2003-01-01

314

Feedforward and feedback projections of caudal belt and parabelt areas of auditory cortex: refining the hierarchical model.  

PubMed

Our working model of the primate auditory cortex recognizes three major regions (core, belt, parabelt), subdivided into thirteen areas. The connections between areas are topographically ordered in a manner consistent with information flow along two major anatomical axes: core-belt-parabelt and caudal-rostral. Remarkably, most of the connections supporting this model were revealed using retrograde tracing techniques. Little is known about laminar circuitry, as anterograde tracing of axon terminations has rarely been used. The purpose of the present study was to examine the laminar projections of three areas of auditory cortex, pursuant to analysis of all areas. The selected areas were: middle lateral belt (ML); caudomedial belt (CM); and caudal parabelt (CPB). Injections of anterograde tracers yielded data consistent with major features of our model, and also new findings that compel modifications. Results supporting the model were: (1) feedforward projection from ML and CM terminated in CPB; (2) feedforward projections from ML and CPB terminated in rostral areas of the belt and parabelt; and (3) feedback projections typified inputs to the core region from belt and parabelt. At odds with the model was the convergence of feedforward inputs into rostral medial belt from ML and CPB. This was unexpected since CPB is at a higher stage of the processing hierarchy, with mainly feedback projections to all other belt areas. Lastly, extending the model, feedforward projections from CM, ML, and CPB overlapped in the temporal parietal occipital area (TPO) in the superior temporal sulcus, indicating significant auditory influence on sensory processing in this region. The combined results refine our working model and highlight the need to complete studies of the laminar inputs to all areas of auditory cortex. Their documentation is essential for developing informed hypotheses about the neurophysiological influences of inputs to each layer and area. PMID:24795550

Hackett, Troy A; de la Mothe, Lisa A; Camalier, Corrie R; Falchier, Arnaud; Lakatos, Peter; Kajikawa, Yoshinao; Schroeder, Charles E

2014-01-01

315

Elastic instabilities in a layered cerebral cortex: A revised axonal tension model for cortex folding  

E-print Network

We model the viscoelasticity of the cerebral cortex as a layered material with bending energy along the layers and elastic energy between them in both planar and polar geometries. The cortex is also subjected to axons pulling from the underlying white matter. Above a critical threshold force, a "flat" cortex configuration becomes unstable and periodic unduluations emerge, i.e. a buckling instability occurs. These undulations may indeed initiate folds in the cortex. We identify analytically the critical force and the critical wavelength of the undulations. Both quantities are physiologically relevant values. Our model is a revised version of the axonal tension model for cortex folding, with the initial version invoking circumferential axon pulling, which is not necessarily in keeping with observations. Moreover, our model draws a connection with another competing model for cortex folding, namely the differential growth-induced buckling model. For the polar geometry, we study the relationship between brain size and the critical force and wavelength to understand why small mice brains exhibit no folds, while larger human brains do, for example. Finally, an estimate of the bending rigidity constant for the cortex can be made based on the critical wavelength.

O. V. Manyuhina; David Mayett; J. M. Schwarz

2014-07-14

316

Keynote Address: Revaluing the Orbital Prefrontal Cortex  

PubMed Central

The importance of orbitofrontal cortex (OFC) in human behavioral regulation is no longer a matter of dispute, though its precise role remains a matter of ongoing investigation. It is ironic that this revaluation of OFC required a major departure from a historical nadir, during which it was viewed as redundant or “silent cortex,” a situation that prevailed even up to the latter half of the 20th century. The increasing wealth of data from diverse fields within neuroscience now provides an unambiguous testament to the importance of this cortical region in behavioral regulation and cognition in general. PMID:17846153

DOLAN, R. J.

2010-01-01

317

Measuring the dynamic longitudinal cortex development in infants by reconstruction of temporally consistent cortical surfaces.  

PubMed

Quantitative measurement of the dynamic longitudinal cortex development during early postnatal stages is of great importance to understand the early cortical structural and functional development. Conventional methods usually reconstruct the cortical surfaces of longitudinal images from the same subject independently, which often generate longitudinally-inconsistent cortical surfaces and thus lead to inaccurate measurement of cortical changes, especially for vertex-wise mapping of cortical development. This paper aims to address this problem by presenting a method to reconstruct temporally-consistent cortical surfaces from longitudinal infant brain MR images, for accurate and consistent measurement of the dynamic cortex development in infants. Specifically, the longitudinal development of the inner cortical surface is first modeled by a deformable growth sheet with elasto-plasticity property to establish longitudinally smooth correspondences of the inner cortical surfaces. Then, the modeled longitudinal inner cortical surfaces are jointly deformed to locate both inner and outer cortical surfaces with a spatial-temporal deformable surface method. The method has been applied to 13 healthy infants, each with 6 serial MR scans acquired at 2 weeks, 3 months, 6 months, 9 months, 12 months and 18 months of age. Experimental results showed that our method with the incorporated longitudinal constraints can reconstruct the longitudinally-dynamic cortical surfaces from serial infant MR images more consistently and accurately than the previously published methods. By using our method, for the first time, we can characterize the vertex-wise longitudinal cortical thickness development trajectory at multiple time points in the first 18 months of life. Specifically, we found the highly age-related and regionally-heterogeneous developmental trajectories of the cortical thickness during this period, with the cortical thickness increased most from 3 to 6 months (16.2%) and least from 9 to 12 months (less than 0.1%). Specifically, the central sulcus only underwent significant increase of cortical thickness from 6 to 9 months and the occipital cortex underwent significant increase from 0 to 9 months, while the frontal, temporal and parietal cortices grew continuously in this first 18 months of life. The adult-like spatial patterns of cortical thickness were generally present at 18 months of age. These results provided detailed insights into the dynamic trajectory of the cortical thickness development in infants. PMID:24374075

Li, Gang; Nie, Jingxin; Wang, Li; Shi, Feng; Gilmore, John H; Lin, Weili; Shen, Dinggang

2014-04-15

318

Enhanced occipital and anterior cingulate activation in men but not in women during exposure to angry and fearful male faces  

Microsoft Academic Search

Blood-oxygenation-level-dependent signal was measured with functional magnetic resonance imaging in 24 healthy young subjects\\u000a (12 men and 12 women) during viewing of angry, fearful, and neutral male and female face pictures. Exposure to angry male\\u000a as opposed to angry female faces activated the visual cortex and the anterior cingulate gyrus significantly more in men than\\u000a in women. A similar sex-differential

Håkan Fischer; Peter Fransson; Christopher I. Wright; Lars Bäckman

2004-01-01

319

Ventromedial Prefrontal Cortex Lesions and Motivational Internalism  

Microsoft Academic Search

This article discusses the argument by Roskies to the effect that ventromedial prefrontal cortex (VMPFC) patients are a living counterexample to motivational internalism. Motivational internalism is a philosophical position according to which moral judgments are accompanied by a particular motivational force that induces agents to act accordingly. Roskies takes into account a very strong version of motivational internalism and claims

Tommaso Bruni

2012-01-01

320

The neuropsychological impact of insular cortex lesions  

Microsoft Academic Search

Influential models based on an increasing body of neuroimaging evidence propose that insular cortex integrates cognitive, affective, sensory and autonomic information to create a consciously perceived, ‘feeling state.’ To appraise these models and evaluate interpretations of neuroimaging findings, the authors review evidence pertaining to the psychological and behavioural consequences of insula lesions. The authors focus on the emotional, perceptual, sensorimotor

Catherine L Jones; Jamie Ward; Hugo D Critchley

2010-01-01

321

Cerebellar Cortex: Computation by Extrasynaptic Inhibition?  

E-print Network

cortex, inhibitory inputs to granule cells exhibit prominent tonic and spillover compo- nents resulting the discovery that it has a strong tonic component [2,3]. This tonic GABA current is much larger than. If the tonic current is indeed caused by GABA spillover, then one would expected it to be blocked

De Schutter, Erik

322

Neurodevelopmental trajectories of the human cerebral cortex.  

PubMed

Understanding the organization of the cerebral cortex remains a central focus of neuroscience. Cortical maps have relied almost exclusively on the examination of postmortem tissue to construct structural, architectonic maps. These maps have invariably distinguished between areas with fewer discernable layers, which have a less complex overall pattern of lamination and lack an internal granular layer, and those with more complex laminar architecture. The former includes several agranular limbic areas, and the latter includes the homotypical and granular areas of association and sensory cortex. Here, we relate these traditional maps to developmental data from noninvasive neuroimaging. Changes in cortical thickness were determined in vivo from 764 neuroanatomic magnetic resonance images acquired longitudinally from 375 typically developing children and young adults. We find differing levels of complexity of cortical growth across the cerebrum, which align closely with established architectonic maps. Cortical regions with simple laminar architecture, including most limbic areas, predominantly show simpler growth trajectories. These areas have clearly identified homologues in all mammalian brains and thus likely evolved in early mammals. In contrast, polysensory and high-order association areas of cortex, the most complex areas in terms of their laminar architecture, also have the most complex developmental trajectories. Some of these areas are unique to, or dramatically expanded in primates, lending an evolutionary significance to the findings. Furthermore, by mapping a key characteristic of these development trajectories (the age of attaining peak cortical thickness) we document the dynamic, heterochronous maturation of the cerebral cortex through time lapse sequences ("movies"). PMID:18385317

Shaw, Philip; Kabani, Noor J; Lerch, Jason P; Eckstrand, Kristen; Lenroot, Rhoshel; Gogtay, Nitin; Greenstein, Deanna; Clasen, Liv; Evans, Alan; Rapoport, Judith L; Giedd, Jay N; Wise, Steve P

2008-04-01

323

Cognitive Neuroscience Phylogeny of the cortex  

E-print Network

reaches more than 2 mm in full development. #12;Neurons proliferate and migrate within radial columnarCognitive Neuroscience Section 2 Phylogeny of the cortex The neocortex of mammals developed out with evolution in comparison to the rest of the brain. The process by which the neocortex becomes larger

Bressler, Steven L.

324

Microglia in the Cerebral Cortex in Autism  

ERIC Educational Resources Information Center

We immunocytochemically identified microglia in fronto-insular (FI) and visual cortex (VC) in autopsy brains of well-phenotyped subjects with autism and matched controls, and stereologically quantified the microglial densities. Densities were determined blind to phenotype using an optical fractionator probe. In FI, individuals with autism had…

Tetreault, Nicole A.; Hakeem, Atiya Y.; Jiang, Sue; Williams, Brian A.; Allman, Elizabeth; Wold, Barbara J.; Allman, John M.

2012-01-01

325

The chronoarchitecture of the cerebral cortex  

Microsoft Academic Search

We review here a new approach to mapping the human cerebral cortex into distinct subdivisions. Unlike cytoarchitecture or traditional functional imaging, it does not rely on specific anatomical markers or functional hypotheses. Instead, we propose that the unique activity time course (ATC) of each cortical subdivision, elicited during natural conditions, acts as a temporal fingerprint that can be used to

Andreas Bartels; Semir Zeki

2005-01-01

326

The insular cortex: a comparative perspective.  

PubMed

The human insular cortex is involved in a variety of viscerosensory, visceromotor, and interoceptive functions, and plays a role in complex processes such as emotions, music, and language. Across mammals, the insula has considerable morphologic variability. We review the structure and connectivity of the insula in laboratory animals (mouse, domestic cat, macaque monkey), and we present original data on the morphology and cytoarchitecture of insular cortex in less common species including a large carnivore (the Atlantic walrus, Odobenus rosmarus), two artiodactyls (the pigmy hippopotamus, Hexaprotodon liberiensis, and the Western bongo, Tragelaphus eurycerus), two cetaceans (the beluga whale, Delphinapterus leucas, and the minke whale, Balaenoptera acutorostrata), and a sirenian (the Florida manatee, Trichechus manatus latirostris). The insula shows substantial variability in shape, extent, and gyral and sulcal patterns, as well as differences in laminar organization, cellular specialization, and structural association with the claustrum. Our observations reveal that the insular cortex is extremely variable among mammals. These differences could be related to the role exerted by specific and selective pressures on cortical structure during evolution. We conclude that it is not possible to identify a general model of organization for the mammalian insular cortex. PMID:20512368

Butti, Camilla; Hof, Patrick R

2010-06-01

327

Microcolumns in the cerebral cortex Edward G. Jones  

E-print Network

Microcolumns in the cerebral cortex Edward G. Jones doi:10.1073/pnas.97.10.5019 2000 Microcolumns in the cerebral cortex Edward G. Jones* Center for Neuroscience, University of California, Davis, CA 95616 Neuroanatomists from Cajal on (1) have searched in the cerebral cortex for units

Stanley, H. Eugene

328

Cerebral Cortex doi:10.1093/cercor/bhm256  

E-print Network

Cerebral Cortex doi:10.1093/cercor/bhm256 V1 Projection Zone Signals in Human Macular Degeneration, plasticity, retinal degeneration, visual cortex Introduction During visual development abnormal retinal cortex, for example, congenital retinal disease transforms the visual field map in human primary visual

Wandell, Brian A.

329

INTRODUCTION During embryogenesis, neurons of the cerebral cortex are  

E-print Network

INTRODUCTION During embryogenesis, neurons of the cerebral cortex are generated in the ventricular in the cerebral cortex employed glia as their sole substratum and consequently followed strictly radial pathways., 1988; Turner and Cepko, 1987; Wetts and Fraser, 1988), clones in the cerebral cortex spread

McConnell, Susan

330

Cell Counts in Cerebral Cortex of an Autistic Patient.  

ERIC Educational Resources Information Center

Numbers of neurons and glia were counted in the cerebral cortex of one case of autism and two age- and sex-matched controls. Cell counts were made in primary auditory cortex, Broca's speech area, and auditory association cortex. No consistent differences in cell density were found between brains of autistic and control patients. (Author/CL)

Coleman, Paul D.; And Others

1985-01-01

331

Computerized Mappings of the Cerebral Cortex: A Multiresolution Flattening Method  

E-print Network

Computerized Mappings of the Cerebral Cortex: A Multiresolution Flattening Method and a Surface two-dimensionnl maps of the cerebral cortex. Our computerized,two-stageflat- tening method takes finer resolution maps.We demonstr;ite INTRODUCTION The extensive convolutions of the cerebral cortex

Van Essen, David

332

Global optimization of cerebral cortex layout Christopher Cherniak*  

E-print Network

Global optimization of cerebral cortex layout Christopher Cherniak* , Zekeria Mokhtarzada*, Raul cerebral cortex seem positioned to minimize costs of their interconnections, down to a best-in-a- billion layout of sensory areas of macaque and cat cerebral cortex. The areas appear to be positioned

Cherniak, Christopher

333

ORIGINAL ARTICLE Quantitative trait loci linked to thalamus and cortex  

E-print Network

ORIGINAL ARTICLE Quantitative trait loci linked to thalamus and cortex gray matter volumes in BXD there are separate or shared genetic influences on the development of the thalamus and cerebral cortex, we identified of the entire thalamus and cortex gray matter using point counting and Cavalieri's rule. Heritability

Cheverud, James M.

334

Stimulus context modulates competition in human extrastriate cortex  

E-print Network

multiple stimuli are eliminated in extrastriate cortex when they are presented in the context of pop items differ from each other. The pop-out effects seemed to originate in early visual cortex and were in the visual cortex in single-cell physiology and functional brain imaging studies, showing that multiple

Kastner, Sabine

335

Cell counts in cerebral cortex of an autistic patient  

Microsoft Academic Search

Numbers of neurons and glia were counted in the cerebral cortex of one well-documented case of autism and two age and sexmatched controls. Areas in which cell counts were made were primary auditory cortex, Broca's speech area, and auditory association cortex. No consistent differences in cell density were found between the brains of the autistic patient and the control patients.

Paul D. Coleman; John Romano; Lowell Lapham; William Simon

1985-01-01

336

Cerebral Cortex Structure in Prodromal Huntington Disease  

PubMed Central

Neuroimaging studies of subjects who are gene-expanded for Huntington Disease, but not yet diagnosed (termed prodromal HD), report that the cortex is “spared,” despite the decrement in striatal and cerebral white-matter volume. Measurement of whole-cortex volume can mask more subtle, but potentially clinically relevant regional changes in volume, thinning, or surface area. The current study addressed this limitation by evaluating cortical morphology of 523 prodromal HD subjects. Participants included 693 individuals enrolled in the PREDICT-HD protocol. Of these participants, 523 carried the HD gene mutation (prodromal HD group); the remaining 170 were non gene-expanded and served as the comparison group. Based on age and CAG repeat length, gene-expanded subjects were categorized as “Far from onset,” “Midway to onset,” “Near onset,” and “already diagnosed.” MRI scans were processed using FreeSurfer. Cortical volume, thickness, and surface area were not significantly different between the Far from onset group and controls. However, beginning in the Midway to onset group, the cortex showed significant volume decrement, affecting most the posterior and superior cerebral regions. This pattern progressed when evaluating the groups further into the disease process. Areas that remained mostly unaffected included ventral and medial regions of the frontal and temporal cortex. Morphologic changes were mostly in thinning as surface area did not substantially change in most regions. Early in the course of HD, the cortex shows changes that are manifest as cortical thinning and are most robust in the posterior and superior regions of the cerebrum. PMID:20688164

Nopoulos, Peggy C.; Aylward, Elizabeth H.; Ross, Christopher A.; Johnson, Hans J.; Magnotta, Vincent A.; Juhl, Andrew R.; Pierson, Ronald K.; Mills, James; Langbehn, Douglas R.; Paulsen, Jane S.

2010-01-01

337

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

PubMed

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

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

2014-03-01

338

Effect of Visual Feedback on the Occipital-Parietal-Motor Network in Parkinson's Disease with Freezing of Gait  

PubMed Central

Freezing of gait (FOG) is an elusive phenomenon that debilitates a large number of Parkinson’s disease (PD) patients regardless of stage of disease, medication status, or deep brain stimulation implantation. Sensory feedback cues, especially visual feedback cues, have been shown to alleviate FOG episodes or even prevent episodes from occurring. Here, we examine cortical information flow between occipital, parietal, and motor areas during the pre-movement stage of gait in a PD-with-FOG patient that had a strong positive behavioral response to visual cues, one PD-with-FOG patient without any behavioral response to visual cues, and age-matched healthy controls, before and after training with visual feedback. Results for this case study show differences in cortical information flow between the responding PD-with-FOG patient and the other two subject types, notably, an increased information flow in the beta range. Tentatively suggesting the formation of an alternative cortical sensory-motor pathway during training with visual feedback, these results are proposed as subject for further verification employing larger cohorts of patients. PMID:24409167

Velu, Priya D.; Mullen, Tim; Noh, Eunho; Valdivia, Matthew C.; Poizner, Howard; Baram, Yoram; de Sa, Virginia R.

2014-01-01

339

Novel method of knotless vesicourethral anastomosis during robot-assisted radical prostatectomy: feasibility study and early outcomes in 30 patients using the interlocked barbed unidirectional V-LOC180 suture  

PubMed Central

Purpose: Our purpose was to describe the safety and feasibility of a running posterior reconstruction (PR) integrated with continuous vesicourethral anastomosis (VUA) using a novel self-cinching unidirectional barbed suture in robot-assisted radical prostatectomy (RARP). Methods: Between March and October 2010, 30 consecutive patients with organ-confined prostate cancer underwent RARP by an experienced single surgeon (KCZ). Upon completion of radical prostatectomy, urinary reconstruction was carried out using 2 knotless, interlocked 6-inches 3-0 V-Loc-180 suture. The left tail of the suture was initially used for PR (starting at 5-o’clock and ran to re-approximate the retrotrigonal layer to the rectourethralis) followed by left-sided VUA (from 6- to 12-o’clock), while the right-sided suture completed the right-sided VUA. Assurance of watertight closure with an intraoperative 300 cc saline visual cystogram was performed in all cases prior to case completion. Perioperative outcomes and 30-day complications were recorded. Results: All anastamoses were performed without assistance and without knot tying. Median time for nurse setup and urinary reconstruction was 40 seconds (interquartile range [IQR] 25–60) and 14.6 min (IQR 10–18), respectively. The need to readjust suture tension or place Lapra-Ty clips (Ethicon Endo-Surgery, Cincinnati, OH) to establish watertight closure was observed in 2 cases (7%). No patient had clinical urinary leak and there was no urinary retention after catheter removal on mean postoperative day 5 (IQR 4–6). Conclusions: Our clinical experience with a novel technique using the interlocked V-Loc suture during RARP for both PR and anastomosis appears to be safe and efficient. Using the barbed suture prevents slippage and eliminates the need for bedside assistance to maintain suture tension or knot tying, thus assuring watertight tissue closure. PMID:21672482

Zorn, Kevin C.; Widmer, Hugues; Lattouf, Jean-Baptiste; Liberman, Dan; Bhojani, Naeem; Trinh, Quoc-Dien; Sun, Maxine; Karakiewicz, Pierre I.; Denis, Ronald; El-Hakim, Assaad

2011-01-01

340

The role of the premotor cortex and the primary motor cortex in action verb comprehension: evidence from Granger causality analysis.  

PubMed

Although numerous studies find the premotor cortex and the primary motor cortex are involved in action language comprehension, so far the nature of these motor effects is still in controversy. Some researchers suggest that the motor effects reflect that the premotor cortex and the primary motor cortex make functional contributions to the semantic access of action verbs, while other authors argue that the motor effects are caused by comprehension. In the current study, we used Granger causality analysis to investigate the roles of the premotor cortex and the primary motor cortex in processing of manual-action verbs. Regions of interest were selected in the primary motor cortex (M1) and the premotor cortex based on a hand motion task, and in the left posterior middle temporal gyrus (lexical semantic area) based on the reading task effect. We found that (1) the left posterior middle temporal gyrus had a causal influence on the left M1; and (2) the left posterior middle temporal gyrus and the left premotor cortex had bidirectional causal relations. These results suggest that the premotor cortex and the primary motor cortex play different roles in manual verb comprehension. The premotor cortex may be involved in motor simulation that contributes to action language processing, while the primary motor cortex may be engaged in a processing stage influenced by the meaning access of manual-action verbs. Further investigation combining effective connectivity analysis and technique with high temporal resolution is necessary for better clarification of the roles of the premotor cortex and the primary motor cortex in action language comprehension. PMID:22524996

Yang, Jie; Shu, Hua

2012-08-01

341

Age estimation using CT imaging of the third molar tooth, the medial clavicular epiphysis, and the spheno-occipital synchondrosis: A multifactorial approach  

Microsoft Academic Search

A multi-factorial method for estimating age was devised based on the development of the 3rd molar tooth, the medial clavicular epiphysis, and the spheno-occipital synchondrosis, using multiple regression as the means to construct age estimation formulae and CT scanning as the imaging modality. The sample consisted of approximately 600 individuals from a contemporary Australian population, between the ages of 15

Richard B. Bassed; Christopher Briggs; Olaf H. Drummer

2011-01-01

342

Social Distance Evaluation in Human Parietal Cortex  

PubMed Central

Across cultures, social relationships are often thought of, described, and acted out in terms of physical space (e.g. “close friends” “high lord”). Does this cognitive mapping of social concepts arise from shared brain resources for processing social and physical relationships? Using fMRI, we found that the tasks of evaluating social compatibility and of evaluating physical distances engage a common brain substrate in the parietal cortex. The present study shows the possibility of an analytic brain mechanism to process and represent complex networks of social relationships. Given parietal cortex's known role in constructing egocentric maps of physical space, our present findings may help to explain the linguistic, psychological and behavioural links between social and physical space. PMID:19204791

Yamakawa, Yoshinori; Kanai, Ryota; Matsumura, Michikazu; Naito, Eiichi

2009-01-01

343

Anterior Insular Cortex and Emotional Awareness  

PubMed Central

This paper reviews the foundation for a role of the human anterior insular cortex (AIC) in emotional awareness, defined as the conscious experience of emotions. We first introduce the neuroanatomical features of AIC and existing findings on emotional awareness. Using empathy, the awareness and understanding of other people’s emotional states, as a test case, we then present evidence to demonstrate: 1) AIC and anterior cingulate cortex (ACC) are commonly coactivated as revealed by a meta-analysis, 2) AIC is functionally dissociable from ACC, 3) AIC integrates stimulus-driven and top-down information, and 4) AIC is necessary for emotional awareness. We propose a model in which AIC serves two major functions: integrating bottom-up interoceptive signals with top-down predictions to generate a current awareness state and providing descending predictions to visceral systems that provide a point of reference for autonomic reflexes. We argue that AIC is critical and necessary for emotional awareness. PMID:23749500

Gu, Xiaosi; Hof, Patrick R.; Friston, Karl J.; Fan, Jin

2014-01-01

344

Social distance evaluation in human parietal cortex.  

PubMed

Across cultures, social relationships are often thought of, described, and acted out in terms of physical space (e.g. "close friends" "high lord"). Does this cognitive mapping of social concepts arise from shared brain resources for processing social and physical relationships? Using fMRI, we found that the tasks of evaluating social compatibility and of evaluating physical distances engage a common brain substrate in the parietal cortex. The present study shows the possibility of an analytic brain mechanism to process and represent complex networks of social relationships. Given parietal cortex's known role in constructing egocentric maps of physical space, our present findings may help to explain the linguistic, psychological and behavioural links between social and physical space. PMID:19204791

Yamakawa, Yoshinori; Kanai, Ryota; Matsumura, Michikazu; Naito, Eiichi

2009-01-01

345

Monkey cortex through fMRI glasses.  

PubMed

In 1998 several groups reported the feasibility of fMRI experiments in monkeys, with the goal to bridge the gap between invasive nonhuman primate studies and human functional imaging. These studies yielded critical insights in the neuronal underpinnings of the BOLD signal. Furthermore, the technology has been successful in guiding electrophysiological recordings and identifying focal perturbation targets. Finally, invaluable information was obtained concerning human brain evolution. We here provide a comprehensive overview of awake monkey fMRI studies mainly confined to the visual system. We review the latest insights about the topographic organization of monkey visual cortex and discuss the spatial relationships between retinotopy and category- and feature-selective clusters. We briefly discuss the functional layout of parietal and frontal cortex and continue with a summary of some fascinating functional and effective connectivity studies. Finally, we review recent comparative fMRI experiments and speculate about the future of nonhuman primate imaging. PMID:25102559

Vanduffel, Wim; Zhu, Qi; Orban, Guy A

2014-08-01

346

The prefrontal cortex: categories, concepts and cognition  

Microsoft Academic Search

The ability to generalize behaviour-guiding principles and concepts from experience is key to intelligent, goal-directed behaviour. It allows us to deal efé ciently with a complex world and to adapt readily to novel situations. We review evidence that the prefrontal cortex—the cortical area that reaches its greatest elaboration in primates—plays a central part in acquiring and representing this information. The

Earl K. Miller; David J. Freedman; Jonathan D. Wallis

2002-01-01

347

Hue maps in primate striate cortex  

Microsoft Academic Search

The macaque striate cortex (V1) contains neurons that respond preferentially to various hues. The properties of these hue-selective neurons have been studied extensively at the single-unit level, but it is unclear how stimulus hue is represented by the distribution of activity across neuronal populations in V1. Here we use the intrinsic optical signal to image V1 responses to spatially uniform

Youping Xiao; Alexander Casti; Jun Xiao; Ehud Kaplan

2007-01-01

348

Role of visual cortex in interocular alignment.  

PubMed

The role which the visual cortex plays in the development of interocular alignment in the cat was examined by removing this structure bilaterally in 4 groups of subjects. These included (1) kittens 10 to 14 days of age, (2) 10- to 14-day-old kittens in which one eyelid was sutured shut at the same time, (3) normally reared adult cats, and (4) cats dark-reared until 4 months of age. If the cortex is removed in young kittens, interocular alignment appears to develop normally until the kittens are 60 to 80 days of age. At this time, an abrupt change in alignment resulting in incyclotorsion of the optic axes is observed. If binocular vision is prevented in kittens with neonatal visual cortex lesions by suturing one eyelid shut, convergent strabismus and/or incyclotorsion are frequently observed. This characteristic incyclotorsion does not develop if similar lesions are made in adult cats; no significant alterations of eye alignment occur in these animals even after postoperative survival times of more than 6 months. Incyclotorsion characterizes dark-reared cats when they are first brought into the light, but this diminishes with time and may even be replaced by excyclotorsion after the animals spend a few weeks in the light. If dark-reared cats are decorticated on being brought into the light, these changes are largely prevented. Such animals remain permanently incyclotorted relative to normal cats. The results indicate that the visual cortex plays an important role in the development of torsional alignment of the eyes. PMID:447472

Cynader, M

1979-07-01

349

Motor cortex stimulation for neuropathic pain  

Microsoft Academic Search

Since the initial publication of Tsubokawa in 1991, epidural motor cortex stimulation (MCS) is increasingly reported as an\\u000a effective surgical option for the treatment of refractory neuropathic pain although its mechanism of action remains poorly\\u000a understood. The authors review the extensive literature published over the last 15 years on central and neuropathic pain.\\u000a Optimal patient selection remains difficult and the

Yves Lazorthes; J. C. Sol; S. Fowo; F. E. Roux; J. C. Verdié

350

Auditory motion processing after early blindness.  

PubMed

Studies showing that occipital cortex responds to auditory and tactile stimuli after early blindness are often interpreted as demonstrating that early blind subjects "see" auditory and tactile stimuli. However, it is not clear whether these occipital responses directly mediate the perception of auditory/tactile stimuli, or simply modulate or augment responses within other sensory areas. We used fMRI pattern classification to categorize the perceived direction of motion for both coherent and ambiguous auditory motion stimuli. In sighted individuals, perceived motion direction was accurately categorized based on neural responses within the planum temporale (PT) and right lateral occipital cortex (LOC). Within early blind individuals, auditory motion decisions for both stimuli were successfully categorized from responses within the human middle temporal complex (hMT+), but not the PT or right LOC. These findings suggest that early blind responses within hMT+ are associated with the perception of auditory motion, and that these responses in hMT+ may usurp some of the functions of nondeprived PT. Thus, our results provide further evidence that blind individuals do indeed "see" auditory motion. PMID:25378368

Jiang, Fang; Stecker, G Christopher; Fine, Ione

2014-01-01

351

Auditory motion processing after early blindness  

PubMed Central

Studies showing that occipital cortex responds to auditory and tactile stimuli after early blindness are often interpreted as demonstrating that early blind subjects “see” auditory and tactile stimuli. However, it is not clear whether these occipital responses directly mediate the perception of auditory/tactile stimuli, or simply modulate or augment responses within other sensory areas. We used fMRI pattern classification to categorize the perceived direction of motion for both coherent and ambiguous auditory motion stimuli. In sighted individuals, perceived motion direction was accurately categorized based on neural responses within the planum temporale (PT) and right lateral occipital cortex (LOC). Within early blind individuals, auditory motion decisions for both stimuli were successfully categorized from responses within the human middle temporal complex (hMT+), but not the PT or right LOC. These findings suggest that early blind responses within hMT+ are associated with the perception of auditory motion, and that these responses in hMT+ may usurp some of the functions of nondeprived PT. Thus, our results provide further evidence that blind individuals do indeed “see” auditory motion. PMID:25378368

Jiang, Fang; Stecker, G. Christopher; Fine, Ione

2014-01-01

352

Amodal Processing in Human Prefrontal Cortex  

PubMed Central

Information enters the cortex via modality-specific sensory regions, whereas actions are produced by modality-specific motor regions. Intervening central stages of information processing map sensation to behavior. Humans perform this central processing in a flexible, abstract manner such that sensory information in any modality can lead to response via any motor system. Cognitive theories account for such flexible behavior by positing amodal central information processing (e.g., “central executive,” Baddeley and Hitch, 1974; “supervisory attentional system,” Norman and Shallice, 1986; “response selection bottleneck,” Pashler, 1994). However, the extent to which brain regions embodying central mechanisms of information processing are amodal remains unclear. Here we apply multivariate pattern analysis to functional magnetic resonance imaging (fMRI) data to compare response selection, a cognitive process widely believed to recruit an amodal central resource across sensory and motor modalities. We show that most frontal and parietal cortical areas known to activate across a wide variety of tasks code modality, casting doubt on the notion that these regions embody a central processor devoid of modality representation. Importantly, regions of anterior insula and dorsolateral prefrontal cortex consistently failed to code modality across four experiments. However, these areas code at least one other task dimension, process (instantiated as response selection vs response execution), ensuring that failure to find coding of modality is not driven by insensitivity of multivariate pattern analysis in these regions. We conclude that abstract encoding of information modality is primarily a property of subregions of the prefrontal cortex. PMID:23843526

Dux, Paul E.; Tombu, Michael N.; Asplund, Christopher L.; Marois, Rene

2013-01-01

353

The basic nonuniformity of the cerebral cortex  

PubMed Central

Evolutionary changes in the size of the cerebral cortex, a columnar structure, often occur through the addition or subtraction of columnar modules with the same number of neurons underneath a unit area of cortical surface. This view is based on the work of Rockel et al. [Rockel AJ, Hiorns RW, Powell TP (1980) The basic uniformity in structure of the neocortex. Brain 103:221–244], who found a steady number of approximately 110 neurons underneath a surface area of 750 ?m2 (147,000 underneath 1 mm2) of the cerebral cortex of five species from different mammalian orders. These results have since been either corroborated or disputed by different groups. Here, we show that the number of neurons underneath 1 mm2 of the cerebral cortical surface of nine primate species and the closely related Tupaia sp. is not constant and varies by three times across species. We found that cortical thickness is not inversely proportional to neuronal density across species and that total cortical surface area increases more slowly than, rather than linearly with, the number of neurons underneath it. The number of neurons beneath a unit area of cortical surface varies linearly with neuronal density, a parameter that is neither related to cortical size nor total number of neurons. Our finding of a variable number of neurons underneath a unit area of the cerebral cortex across primate species indicates that models of cortical organization cannot assume that cortical columns in different primates consist of invariant numbers of neurons. PMID:18689685

Herculano-Houzel, Suzana; Collins, Christine E.; Wong, Peiyan; Kaas, Jon H.; Lent, Roberto

2008-01-01

354

Binocular form deprivation influences the visual cortex?  

PubMed Central

?-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors are considered to play a crucial role in synaptic plasticity in the developing visual cortex. In this study, we established a rat model of binocular form deprivation by suturing the rat binocular eyelids before eye-opening at postnatal day 14. During development, the decay time of excitatory postsynaptic currents mediated by ?-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors of normal rats became longer after eye-opening; however, the decay time did not change significantly in binocular form deprivation rats. The peak value in the normal group became gradually larger with age, but there was no significant change in the binocular form deprivation group. These findings indicate that binocular form deprivation influences the properties of excitatory postsynaptic currents mediated by ?-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors in the rat visual cortex around the end of the critical period, indicating that form stimulation is associated with the experience-dependent modification of neuronal synapses in the visual cortex. PMID:25337118

Liu, Mingming; Weng, Chuanhuang; Xie, Hanping; Qin, Wei

2012-01-01

355

Secure Surgical Method for Catheter Placement via the Occipital Artery to Achieve Retrograde Superselective Intra-Arterial Chemotherapy for Advanced Oral Cancer: Alternative to Approach via the Superficial Temporal Artery.  

PubMed

We describe secure surgical method for catheter placement using ultrasonic scalpel via the occipital artery to achieve retrograde superselective intra-arterial chemotherapy for advanced oral cancer, as alternative to approach via the superficial temporal artery. PMID:24822164

Iwai, Toshinori; Fuwa, Nobukazu; Hirota, Makoto; Mitsudo, Kenji; Tohnai, Iwai

2014-06-01

356

Neural Substrates of Visual Spatial Coding and Visual Feedback Control for Hand Movements in Allocentric and Target-Directed Tasks  

PubMed Central

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 movements. PMID:21941474

Thaler, Lore; Goodale, Melvyn A.

2011-01-01

357

Selectivity for large nonmanipulable objects in scene-selective visual cortex does not require visual experience  

E-print Network

objects was additionally observed in the retrosplenial complex (RSC) and the transverse occipital sulcus representations in VTC can develop, at least partly, without visual experience. © 2013 Elsevier Inc. All rights additional regions in the retrosplenial com- plex (RSC) and the transverse occipital sulcus (TOS) (e

Caramazza, Alfonso

358

Psychostimulant treatment and the developing cortex in Attention-Deficit/Hyperactivity Disorder  

PubMed Central

Objective While there has been considerable concern over possible adverse effects of psychostimulants on brain development, no prospective study has examined this issue. We determined whether psychostimulant drug treatment for Attention-deficit/Hyperactivity Disorder (ADHD) was associated with differences in the development of the cerebral cortex during adolescence. Method Change in cortical thickness was estimated from two neuroanatomic magnetic resonance images on 43 subjects with DSM-IV ADHD (mean age at first scan 12.5 years (SD 2.1); second scan 16.4 (SD2.4). Nineteen subjects not treated with psychostimulants between the scans were compared with an age matched group of 24 subjects who received psychostimulants. Further comparison was made against a template derived from 620 scans on 294 typically developing children. Results Treatment defined ADHD groups differed in rate of change of cortical thickness of the right motor strip, the left middle/inferior frontal gyrus; and the right parieto-occipital region (t(41)=2.8, p=0.009) The group difference was due to more rapid cortical thinning in the group ‘off’ psychostimulants (mean cortical thinning of 0.16mm/year, SD 0.17) compared to the ‘on’ group (thinning of 0.03 mm/year, SD 0.11). Comparison against a typically developing cohort showed the cortical thinning in the ‘off’ psychostimulants group was in excess of age appropriate rates. Treatment groups did not differ however in clinical outcome. Conclusions There was no evidence that psychostimulants were associated with ‘slowing’ of overall growth of the cortical mantle. PMID:18794206

Shaw, Philip; Sharp, Wendy; Morrison, Meaghan; Eckstrand, Kristen; Greenstein, Deanna; Clasen, Liv; Evans, Alan; Rapoport, Judith L.

2009-01-01

359

FMRI analysis of contrast polarity processing in face-selective cortex in humans and monkeys  

PubMed Central

Recognition is strongly impaired when the normal contrast polarity of faces is reversed. For instance, otherwise-familiar faces become very difficult to recognize when viewed as photographic negatives. Here, we used fMRI to demonstrate related properties in visual cortex: 1) fMRI responses in the human Fusiform Face Area (FFA) decreased strongly (26%) to contrast-reversed faces across a wide range of contrast levels (5.3-100% RMS contrast), in all subjects tested. In a whole brain analysis, this contrast polarity bias was largely confined to the Fusiform Face Area (FFA; p < 0.0001), with possible involvement of a left occipital face-selective region. 2) It is known that reversing facial contrast affects three image properties in parallel (absorbance, shading, and specular reflection). Here, comparison of FFA responses to those in V1 suggests that the contrast polarity bias is produced in FFA only when all three component properties were reversed simultaneously, which suggests a prominent non-linearity in FFA processing. 3) Across a wide range (180°) of illumination source angles, 3D face shapes without texture produced response constancy in FFA, without a contrast polarity bias. 4) Consistent with psychophysics, analogous fMRI biases for normal contrast polarity were not produced by non-face objects, with image statistics similar to the face stimuli. 5) Using fMRI, we also demonstrated a contrast polarity bias in awake behaving macaque monkeys, in the cortical region considered homologous to human FFA. Thus common cortical mechanisms may underlie facial contrast processing across ~ 25 million years of primate evolution. PMID:23518007

Yue, Xiaomin; Nasr, Shahin; Devaney, Kathryn J.; Holt, Daphne J.; Tootell, Roger B.H.

2013-01-01

360

Involvement of the superior temporal cortex in action execution and action observation.  

PubMed

The role of the superior temporal sulcus (STs) in action execution and action observation remains unsettled. In an attempt to shed more light on the matter, we used the quantitative method of (14)C-deoxyglucose to reveal changes in activity, in the cortex of STs and adjacent inferior and superior temporal convexities of monkeys, elicited by reaching-to-grasp in the light or in the dark and by observation of the same action executed by an external agent. We found that observation of reaching-to-grasp activated the components of the superior temporal polysensory area [STP; including temporo-parieto-occipital association area (TPO), PGa, and IPa], the motion complex [including medial superior temporal area (MST), fundus of superior temporal area (FST), and dorsal and ventral parts of the middle temporal area (MTd and MTv, respectively)], and area TS2. A significant part of most of these activations was associated with observation of the goal-directed action, and a smaller part with the perception of arm-motion. Execution of reaching-to-grasp in the light-activated areas TS2, STP partially and marginally, and MT compared with the fixation but not to the arm-motion control. Consequently, MT-activation is associated with the arm-motion and not with the purposeful action. Finally, reaching-to-grasp in complete darkness activated all components of the motion complex. Conclusively, lack of visibility of our own actions involves the motion complex, whereas observation of others' actions engages area STP and the motion complex. Our previous and present findings together suggest that sensory effects are interweaved with motor commands in integrated action codes, and observation of an action or its execution in complete darkness triggers the retrieval of the visual representation of the action. PMID:24990920

Kilintari, Marina; Raos, Vassilis; Savaki, Helen E

2014-07-01

361

Stimulatory G-protein alpha-subunit mRNA levels are not increased in autopsied cerebral cortex from patients with bipolar disorder.  

PubMed

Increased alpha-subunit (alpha s) levels of both the 45- and 52-kDa isoforms of the stimulatory guanine nucleotide binding protein (G-protein), have been found in postmortem brain and mononuclear leukocytes from patients with bipolar disorder (BD). The pathophysiological mechanism responsible for increased alpha s protein levels is unknown, however, it may involve increased expression of the gene encoding this protein. To assess this possibility, alpha s mRNA levels were determined by RT-PCR in postmortem brain from 10 subjects with an antemortem diagnosis of BD and age- and sex-matched control subjects in whom we had previously reported increased alpha s protein levels. There were no significant differences in alpha s mRNA levels in frontal, temporal, or occipital cortex between BD and control subjects. Cerebral cortex alpha s mRNA levels did not correlate with age or postmortem interval. These findings do not support the notion that higher alpha s levels found in BD postmortem brain are a result of increased gene expression. PMID:8915579

Young, L T; Asghari, V; Li, P P; Kish, S J; Fahnestock, M; Warsh, J J

1996-11-01

362

Reduced Visual Cortex Gray Matter Volume and Thickness in Young Adults Who Witnessed Domestic Violence during Childhood  

PubMed Central

Exposure to interparental violence is associated with negative outcomes, such as depression, post-traumatic stress disorder and reduced cognitive abilities. However, little is known about the potential effects of witnessing domestic violence during childhood on gray matter volume (GMV) or cortical thickness. High-resolution 3.0 T volumetric scans (Siemens Trio Scanner) were obtained on 52 subjects (18–25 years) including 22 (6 males/16 females) with a history of visually witnessing episodes of domestic violence, and 30 (8 males/22 females) unexposed control subjects, with neither a current nor past DSM-IV Axis I or II disorder. Potential confounding effects of age, gender, level of parental verbal aggression, parental education, financial stress, full scale IQ, and total GMV, or average thickness were modeled using voxel based morphometry and FreeSurfer. Witnessing domestic violence subjects had a 6.1% GMV reduction in the right lingual gyrus (BA18) (P?=?0.029, False Discovery Rate corrected peak level). Thickness in this region was also reduced, as was thickness in V2 bilaterally and left occipital pole. Theses regions were maximally sensitive to exposure to witnessing domestic violence between 11–13 years of age. Regional reductions in GMV and thickness were observed in both susceptible and resilient witnessing domestic violence subjects. Results in subjects witnessing domestic violence were similar to previously reported results in subjects with childhood sexual abuse, as the primary region affected was visual cortex. Brain regions that process and convey the adverse sensory input of the abuse may be specifically modified by this experience, particularly in subjects exposed to a single type of maltreatment. Exposure to multiple types of maltreatment is more commonly associated with morphological alterations in corticolimbic regions. These findings fit with preclinical studies showing that visual cortex is a highly plastic structure. PMID:23300699

Tomoda, Akemi; Polcari, Ann; Anderson, Carl M.; Teicher, Martin H.

2012-01-01

363

Functional connectivity of the cortex of term and preterm infants and infants with Down's syndrome.  

PubMed

Near-infrared spectroscopy (NIRS) imaging studies have revealed the functional development of the human brain in early infancy. By measuring spontaneous fluctuations in cerebral blood oxygenation with NIRS, we can examine the developmental status of the functional connectivity of networks in the cortex. However, it has not been clarified whether premature delivery and/or chromosomal abnormalities affect the development of the functional connectivity of the cortex. In the current study, we investigated the spontaneous brain activity of sleeping infants who were admitted to a neonatal intensive care unit at term age. We classified them into the 3 following infant groups: (i) term-or-late-preterm, (ii) early-preterm, and (iii) Down's syndrome (DS). We used multichannel NIRS to measure the spontaneous changes in oxygenated hemoglobin (oxy-Hb) and deoxygenated hemoglobin (deoxy-Hb) at 10 measurement channels, which covered the frontal, temporal, and occipital regions. In order to reveal the functional connectivity of the cortical networks, we calculated the temporal correlations of the time-course signals among all of the pairs of measurement channels. The functional connectivity was classified into the 4 following types: (i) short-range, (ii) contralateral-transverse, (iii) ipsilateral-longitudinal, and (iv) control. In order to examine whether the local properties of hemodynamics reflected any pathological conditions, we calculated the phase differences between the oxy- and deoxy-Hb time-course signals in the 3 groups. The statistical analyses of the functional connectivity data showed main effects of group and the types of connectivity. For the group effect, the mean functional connectivity of the infants in the term-or-late-preterm group did not differ from that in the early-preterm group, and the mean functional connectivity of the infants in the DS group was lower than that in the other 2 groups. For the effect of types of connectivity, short-range connectivity was highest compared to any of the other types of connectivity, and the second highest connectivity was the contralateral-transverse one. The phase differences between the oxy- and deoxy-Hb changes showed that there were significant differences between the DS group and the other 2 groups. Our findings suggested that the development of the functional connectivity of cortical networks did not differ between term-or-late-preterm infants and early-preterm infants around term-equivalent ages, while DS infants had alterations in their functional connectivity development and local hemodynamics at term age. The highest short-range connectivity and the second highest contralateral-transverse connectivity suggested that the precursors for the basic cortical networks of functional connectivity were present at term age. PMID:23631984

Imai, Makiko; Watanabe, Hama; Yasui, Kojiro; Kimura, Yuki; Shitara, Yoshihiko; Tsuchida, Shinya; Takahashi, Naoto; Taga, Gentaro

2014-01-15

364

Long-Term Potentiation in the Motor Cortex  

NASA Astrophysics Data System (ADS)

Long-term potentiation (LTP) is a model for learning and memory processes. Tetanic stimulation of the sensory cortex produces LTP in motor cortical neurons, whereas tetanization of the ventrolateral nucleus of the thalamus, which also projects to the motor cortex, does not. However, after simultaneous high-frequency stimulation of both the sensory cortex and the ventrolateral nucleus of the thalamus, LTP of thalamic input to motor cortical neurons is induced. This associative LTP occurs only in neurons in the superficial layers of the motor cortex that receive monosynaptic input from both the sensory cortex and the ventrolateral nucleus of the thalamus. Associative LTP in the motor cortex may constitute a basis for the retention of motor skills.

Iriki, Atsushi; Pavlides, Constantine; Keller, Asaf; Asanuma, Hiroshi

1989-09-01

365

Neural Pathways Conveying Novisual Information to the Visual Cortex  

PubMed Central

The visual cortex has been traditionally considered as a stimulus-driven, unimodal system with a hierarchical organization. However, recent animal and human studies have shown that the visual cortex responds to non-visual stimuli, especially in individuals with visual deprivation congenitally, indicating the supramodal nature of the functional representation in the visual cortex. To understand the neural substrates of the cross-modal processing of the non-visual signals in the visual cortex, we firstly showed the supramodal nature of the visual cortex. We then reviewed how the nonvisual signals reach the visual cortex. Moreover, we discussed if these non-visual pathways are reshaped by early visual deprivation. Finally, the open question about the nature (stimulus-driven or top-down) of non-visual signals is also discussed. PMID:23840972

2013-01-01

366

The Hyper-Cortex of Human Collective-Intelligence Systems  

Microsoft Academic Search

Individual-intelligence research, from a neurological perspective, describes the cortex as a medium for performing conceptual abstraction and specification. This idea has been used to explain how motor-cortex regions responsible for different behavioral modalities such as writing and speaking can express the same general concept represented in the cortex. For example, the concept of a dog, abstractly represented in the higher-layers

Marko A. Rodriguez

2005-01-01

367

Role of the dorsal premotor cortex in rhythmic auditory-motor entrainment: a perturbational approach by rTMS.  

PubMed

Synchronization of body movements to an external beat is a universal human ability, which has also been recently documented in nonhuman species. The neural substrates of this rhythmic motor entrainment are still under investigation. Correlational neuroimaging data suggest an involvement of the dorsal premotor cortex (dPMC) and the supplementary motor area (SMA). In 14 healthy volunteers, we more specifically investigated the neural network underlying this phenomenon using a causal approach by an established 1-Hz repetitive transcranial magnetic stimulation (rTMS) protocol, which produces a focal suppression of cortical excitability outlasting the stimulation period. Synchronization accuracy between rhythmic cues and right index finger tapping, as measured by the mean time lag (asynchrony) between motor and auditory events, was significantly affected when the right dPMC function was transiently perturbed by "off-line" focal rTMS, whereas the reproduction of the rhythmic sequence per se (inter-tap-interval) was spared. This approach affected metrical rhythms of different complexity, but not non-metrical or isochronous sequences. Conversely, no change in auditory-motor synchronization was observed with rTMS of the SMA, of the left dPMC or over a control site (midline occipital area). Our data strongly support the view that the right dPMC is crucial for rhythmic auditory-motor synchronization in humans. PMID:23236203

Giovannelli, Fabio; Innocenti, Iglis; Rossi, Simone; Borgheresi, Alessandra; Ragazzoni, Aldo; Zaccara, Gaetano; Viggiano, Maria Pia; Cincotta, Massimo

2014-04-01

368

Apraxia, pantomime and the parietal cortex  

PubMed Central

Apraxia, a disorder of higher motor cognition, is a frequent and outcome-relevant sequel of left hemispheric stroke. Deficient pantomiming of object use constitutes a key symptom of apraxia and is assessed when testing for apraxia. To date the neural basis of pantomime remains controversial. We here review the literature and perform a meta-analysis of the relevant structural and functional imaging (fMRI/PET) studies. Based on a systematic literature search, 10 structural and 12 functional imaging studies were selected. Structural lesion studies associated pantomiming deficits with left frontal, parietal and temporal lesions. In contrast, functional imaging studies associate pantomimes with left parietal activations, with or without concurrent frontal or temporal activations. Functional imaging studies that selectively activated parietal cortex adopted the most stringent controls. In contrast to previous suggestions, current analyses show that both lesion and functional studies support the notion of a left-hemispheric fronto-(temporal)-parietal network underlying pantomiming object use. Furthermore, our review demonstrates that the left parietal cortex plays a key role in pantomime-related processes. More specifically, stringently controlled fMRI-studies suggest that in addition to storing motor schemas, left parietal cortex is also involved in activating these motor schemas in the context of pantomiming object use. In addition to inherent differences between structural and functional imaging studies and consistent with the dedifferentiation hypothesis, the age difference between young healthy subjects (typically included in functional imaging studies) and elderly neurological patients (typically included in structural lesion studies) may well contribute to the finding of a more distributed representation of pantomiming within the motor-dominant left hemisphere in the elderly. PMID:24967158

Niessen, E.; Fink, G.R.; Weiss, P.H.

2014-01-01

369

An integrator circuit in cerebellar cortex.  

PubMed

The brain builds dynamic models of the body and the outside world to predict the consequences of actions and stimuli. A well-known example is the oculomotor integrator, which anticipates the position-dependent elasticity forces acting on the eye ball by mathematically integrating over time oculomotor velocity commands. Many models of neural integration have been proposed, based on feedback excitation, lateral inhibition or intrinsic neuronal nonlinearities. We report here that a computational model of the cerebellar cortex, a structure thought to implement dynamic models, reveals a hitherto unrecognized integrator circuit. In this model, comprising Purkinje cells, molecular layer interneurons and parallel fibres, Purkinje cells were able to generate responses lasting more than 10 s, to which both neuronal and network mechanisms contributed. Activation of the somatic fast sodium current by subthreshold voltage fluctuations was able to maintain pulse-evoked graded persistent activity, whereas lateral inhibition among Purkinje cells via recurrent axon collaterals further prolonged the responses to step and sine wave stimulation. The responses of Purkinje cells decayed with a time-constant whose value depended on their baseline spike rate, with integration vanishing at low (< 1 per s) and high rates (> 30 per s). The model predicts that the apparently fast circuit of the cerebellar cortex may control the timing of slow processes without having to rely on sensory feedback. Thus, the cerebellar cortex may contain an adaptive temporal integrator, with the sensitivity of integration to the baseline spike rate offering a potential mechanism of plasticity of the response time-constant. PMID:23731348

Maex, Reinoud; Steuber, Volker

2013-09-01

370

Role of radial glial cells in cerebral cortex folding.  

PubMed

Radial glial cells play key roles during cerebral cortex development, as primary stem and progenitor cells giving rise-directly or indirectly-to neurons and glia, but also acting as scaffold for the cerebral cortex architecture and migrating neurons. Recent work led to the discovery of novel types of radial glial cells with key roles in gyrification, the folding of the mammalian cerebral cortex in phylogeny and ontogeny. Here we summarize the cellular and molecular basis of this fascinating process allowing the expansion of the mammalian cerebral cortex with all its functional consequences. PMID:24632307

Borrell, Víctor; Götz, Magdalena

2014-08-01

371

Modality maps within primate somatosensory cortex Robert M. Friedman*  

E-print Network

during the identification and manipulation of tactile objects. Vibrotactile information is carried stage of primary somatosensory cortex (SI) processing, evidence indicates the presence of segregated mo

Roe, Anna Wang

372

Representation of Multiple, Independent Categories in the Primate Prefrontal Cortex  

E-print Network

Neural correlates of visual categories have been previously identified in the prefrontal cortex (PFC). However, whether individual neurons can represent multiple categories is unknown. Varying degrees of generalization ...

Cromer, Jason A.

373

Modeling spatial patterns in the visual cortex  

NASA Astrophysics Data System (ADS)

We propose a model for the formation of patterns in the visual cortex. The dynamical units of the model are Kuramoto phase oscillators that interact through a complex network structure embedded in two dimensions. In this way the strength of the interactions takes into account the geographical distance between units. We show that for different parameters, clustered or striped patterns emerge. Using the structure factor as an order parameter we are able to quantitatively characterize these patterns and present a phase diagram. Finally, we show that the model is able to reproduce patterns with cardinal preference, as observed in ferrets.

Daza C., Yudy Carolina; Tauro, Carolina B.; Tamarit, Francisco A.; Gleiser, Pablo M.

2014-10-01

374

Prefrontal cortex activity during flexible categorization.  

PubMed

Items are categorized differently depending on the behavioral context. For instance, a lion can be categorized as an African animal or a type of cat. We recorded lateral prefrontal cortex (PFC) neural activity while monkeys switched between categorizing the same image set along two different category schemes with orthogonal boundaries. We found that each category scheme was largely represented by independent PFC neuronal populations and that activity reflecting a category distinction was weaker, but not absent, when that category was irrelevant. We suggest that the PFC represents competing category representations independently to reduce interference between them. PMID:20573899

Roy, Jefferson E; Riesenhuber, Maximilian; Poggio, Tomaso; Miller, Earl K

2010-06-23

375

Somatic sensory cortex of llama (Lama glama).  

PubMed

The somatic sensory cortex (SI and SII) was mapped in llamas using microelectrode mapping methods developed earlier in a study of SI of the slow loris. Projections to SI from the llama's prehensile browsing lips were differentially enlarged when compared to those reported for sheep. In llama, SII was reversed in its mediolatreal pattern from that reported for SII in most other mammals. Fissural landmarks reliably demarcated different projections within SI, between SI and SII and between SI or SII and other surrounding nonsensory areas. The use of microelectrode mapping methods in different mammals to determine gyral and fissural homologies is discussed. PMID:990910

Welker, W I; Adrian, H O; Lifshitz, W; Kaulen, R; Caviedes, E; Gutman, W

1976-01-01

376

Measurements of evoked electroencephalograph by transcranial magnetic stimulation applied to motor cortex and posterior parietal cortex  

NASA Astrophysics Data System (ADS)

To investigate the functional connectivity, the evoked potentials by stimulating at the motor cortex, the posterior parietal cortex, and the cerebellum by transcranial magnetic stimulation (TMS) were measured. It is difficult to measure the evoked electroencephalograph (EEG) by the magnetic stimulation because of the large artifact induced by the magnetic pulse. We used an EEG measurement system with sample-and-hold circuit and an independent component analysis to eliminate the electromagnetic interaction emitted from TMS. It was possible to measure EEG signals from all electrodes over the head within 10 ms after applying the TMS. When the motor area was stimulated by TMS, the spread of evoked electrical activity to the contralateral hemisphere was observed at 20 ms after stimulation. However, when the posterior parietal cortex was stimulated, the evoked electrical activity to the contralateral hemisphere was not observed. When the cerebellum was stimulated, the cortical activity propagated from the stimulated point to the frontal area and the contralateral hemisphere at around 20 ms after stimulation. These results suggest that the motor area has a strong interhemispheric connection and the posterior parietal cortex has no interhemispheric connection.

Iwahashi, Masakuni; Koyama, Yohei; Hyodo, Akira; Hayami, Takehito; Ueno, Shoogo; Iramina, Keiji

2009-04-01

377

Med. Image Comp. and Comp. Asst. Int. (MICCAI), Oct., 1998 Segmentation and Measurement of the Cortex  

E-print Network

been focused on the cerebral cortex. The cerebral cortex is the outermost layer of gray matter]). In the quantitative analysis of these features of the cortex, segmentation is the first step. The cerebral cortex of the Cortex from 3D MR Images Xiaolan Zeng1 , Lawrence H. Staib1 , Robert T. Schultz2 , and James S. Duncan1 1

Duncan, James S.

378

Med. Image Comp. and Comp. Asst. Int. (MICCAI), Oct., 1998 Segmentation and Measurement of the Cortex  

E-print Network

focused on the cerebral cortex. The cerebral cortex is the outermost layer of gray matter in the brain of these features of the cortex, segmentation is the rst step. The cerebral cortex is characterized by its of the Cortex from 3D MR Images Xiaolan Zeng1, Lawrence H. Staib1, Robert T. Schultz2, and James S. Duncan1 1

Duncan, James S.

379

Distinctive Neural Mechanisms Supporting Visual Object Individuation and Identification  

E-print Network

four objects via their spatial locations, the superior IPS and the lateral occipital com- plex (LOC between object individuation and identification has also been noted and it is argued that the development intraparietal sulcus (IPS) and the lateral occipital complex (LOC). These three brain areas were chosen

Xu, Yaoda

380

Haptic shape processing in visual cortex.  

PubMed

Humans typically rely upon vision to identify object shape, but we can also recognize shape via touch (haptics). Our haptic shape recognition ability raises an intriguing question: To what extent do visual cortical shape recognition mechanisms support haptic object recognition? We addressed this question using a haptic fMRI repetition design, which allowed us to identify neuronal populations sensitive to the shape of objects that were touched but not seen. In addition to the expected shape-selective fMRI responses in dorsal frontoparietal areas, we observed widespread shape-selective responses in the ventral visual cortical pathway, including primary visual cortex. Our results indicate that shape processing via touch engages many of the same neural mechanisms as visual object recognition. The shape-specific repetition effects we observed in primary visual cortex show that visual sensory areas are engaged during the haptic exploration of object shape, even in the absence of concurrent shape-related visual input. Our results complement related findings in visually deprived individuals and highlight the fundamental role of the visual system in the processing of object shape. PMID:24345179

Snow, Jacqueline C; Strother, Lars; Humphreys, Glyn W

2014-05-01

381

Vibrissae motor cortex unit activity during whisking  

PubMed Central

Rats generate stereotyped exploratory (5–12 Hz) vibrissa movements when navigating through their environment. Like other rhythmic behaviors, the production of whisking relies on a subcortical pattern generator. However, the relatively large vibrissae representation in motor cortex (vMCx) suggests that cortex also contributes to the control of whisker movements. The goal of this study was to examine the relationship between neuronal activity in vMCx and the kinematics of vibrissae movements. We recorded multiunit activity (MUA) and single units in the rhythmic region of vMCx while measuring vibrissa position in awake, head-restrained rats. The rats were engaged in one of two behavioral tasks where they were rewarded for either 1) producing noncontact whisking epochs that met specified criteria (epochs ?4 Hz, whisks >5 mm) or 2) whisking to contact an object. There was significant coherence between the frequency of MUA and vibrissae movements during free-air whisking but not when animals were using their vibrissae to contact an object. Spike rate in vMCx was most frequently correlated with the amplitude of vibrissa movements; correlations with movement frequency did not exceed chance levels. These findings suggest that the specific parameter under cortical control may be the amplitude of whisker movements. PMID:21994257

Friedman, Wendy A.; Zeigler, H. Philip

2012-01-01

382

Contour extracting networks in early extrastriate cortex.  

PubMed

Neurons in the visual cortex process a local region of visual space, but in order to adequately analyze natural images, neurons need to interact. The notion of an ‘‘association field’’ proposes that neurons interact to extract extended contours. Here, we identify the site and properties of contour integration mechanisms. We used functional magnetic resonance imaging (fMRI) and population receptive field (pRF) analyses. We devised pRF mapping stimuli consisting of contours. We isolated the contribution of contour integration mechanisms to the pRF by manipulating the contour content. This stimulus manipulation led to systematic changes in pRF size. Whereas a bank of Gabor filters quantitatively explains pRF size changes in V1, only V2/V3 pRF sizes match the predictions of the association field. pRF size changes in later visual field maps, hV4, LO-1, and LO-2 do not follow either prediction and are probably driven by distinct classical receptive field properties or other extraclassical integration mechanisms. These pRF changes do not follow conventional fMRI signal strength measures. Therefore, analyses of pRF changes provide a novel computational neuroimaging approach to investigating neural interactions. We interpreted these results as evidence for neural interactions along cooriented, cocircular receptive fields in the early extrastriate visual cortex (V2/V3), consistent with the notion of a contour association field. PMID:24879865

Dumoulin, Serge O; Hess, Robert F; May, Keith A; Harvey, Ben M; Rokers, Bas; Barendregt, Martijn

2014-01-01

383

Retrosplenial Cortex Codes for Permanent Landmarks  

PubMed Central

Landmarks are critical components of our internal representation of the environment, yet their specific properties are rarely studied, and little is known about how they are processed in the brain. Here we characterised a large set of landmarks along a range of features that included size, visual salience, navigational utility, and permanence. When human participants viewed images of these single landmarks during functional magnetic resonance imaging (fMRI), parahippocampal cortex (PHC) and retrosplenial cortex (RSC) were both engaged by landmark features, but in different ways. PHC responded to a range of landmark attributes, while RSC was engaged by only the most permanent landmarks. Furthermore, when participants were divided into good and poor navigators, the latter were significantly less reliable at identifying the most permanent landmarks, and had reduced responses in RSC and anterodorsal thalamus when viewing such landmarks. The RSC has been widely implicated in navigation but its precise role remains uncertain. Our findings suggest that a primary function of the RSC may be to process the most stable features in an environment, and this could be a prerequisite for successful navigation. PMID:22912894

Auger, Stephen D.; Mullally, Sinead L.; Maguire, Eleanor A.

2012-01-01

384

Inactivating anterior insular cortex reduces risk taking.  

PubMed

We often have to make risky decisions between alternatives with outcomes that can be better or worse than the outcomes of safer alternatives. Although previous studies have implicated various brain regions in risky decision making, it remains unknown which regions are crucial for balancing whether to take a risk or play it safe. Here, we focused on the anterior insular cortex (AIC), the causal involvement of which in risky decision making is still unclear, although human imaging studies have reported AIC activation in various gambling tasks. We investigated the effects of temporarily inactivating the AIC on rats' risk preference in two types of gambling tasks, one in which risk arose in reward amount and one in which it arose in reward delay. As a control within the same subjects, we inactivated the adjacent orbitofrontal cortex (OFC), which is well known to affect risk preference. In both gambling tasks, AIC inactivation decreased risk preference whereas OFC inactivation increased it. In risk-free control situations, AIC and OFC inactivations did not affect decision making. These results suggest that the AIC is causally involved in risky decision making and promotes risk taking. The AIC and OFC may be crucial for the opposing motives of whether to take a risk or avoid it. PMID:23136439

Ishii, Hironori; Ohara, Shinya; Tobler, Philippe N; Tsutsui, Ken-Ichiro; Iijima, Toshio

2012-11-01

385

[Risk taking and the insular cortex].  

PubMed

Risk taking can lead to ruin, but sometimes, it can also provide great success. How does our brain make a decision on whether to take a risk or to play it safe? Recent studies have revealed the neural basis of risky decision making. In this review, we focus on the role of the anterior insular cortex (AIC) in risky decision making. Although human imaging studies have shown activations of the AIC in various gambling tasks, the causal involvement of the AIC in risky decision making was still unclear. Recently, we demonstrated a causality of the AIC in risky decision making by using a pharmacological approach in behaving rats-temporary inactivation of the AIC decreased the risk preference in gambling tasks, whereas temporary inactivation of the adjacent orbitofrontal cortex (OFC) increased the risk preference. The latter finding is consistent with a previous finding that patients with damage to the OFC take abnormally risky decisions in the Iowa gambling task. On the basis of these observations, we hypothesize that the intact AIC promotes risk-seeking behavior, and that the AIC and OFC are crucial for balancing the opposing motives of whether to take a risk or avoid it. However, the functional relationship between the AIC and OFC remains unclear. Future combinations of inactivation and electrophysiological studies may promote further understanding of risky decision making. PMID:23917499

Ishii, Hironori; Tsutsui, Ken-Ichiro; Iijima, Toshio

2013-08-01

386

Probabilistic functional tractography of the human cortex.  

PubMed

Single-pulse direct electrical stimulation of cortical regions in patients suffering from focal drug-resistant epilepsy who are explored using intracranial electrodes induces cortico-cortical potentials that can be used to infer functional and anatomical connectivity. Here, we describe a neuroimaging framework that allows development of a new probabilistic atlas of functional tractography of the human cortex from those responses. This atlas is unique because it allows inference in vivo of the directionality and latency of cortico-cortical connectivity, which are still largely unknown at the human brain level. In this technical note, we include 1535 stimulation runs performed in 35 adult patients. We use a case of frontal lobe epilepsy to illustrate the asymmetrical connectivity between the posterior hippocampal gyrus and the orbitofrontal cortex. In addition, as a proof of concept for group studies, we study the probabilistic functional tractography between the posterior superior temporal gyrus and the inferior frontal gyrus. In the near future, the atlas database will be continuously increased, and the methods will be improved in parallel, for more accurate estimation of features of interest. Generated probabilistic maps will be freely distributed to the community because they provide critical information for further understanding and modelling of large-scale brain networks. PMID:23707583

David, Olivier; Job, Anne-Sophie; De Palma, Luca; Hoffmann, Dominique; Minotti, Lorella; Kahane, Philippe

2013-10-15

387

Community-acquired methicillin-resistant Staphylococcus aureus skull base osteomyelitis with occipital condylar cerebrospinal fluid leak in an immunocompetent patient.  

PubMed

Community acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is emerging as an important pathogen in paranasal sinus disease. However, sinonasal CA-MRSA has not been reported as a source of central skull base osteomyelitis. We report an unusual case of a previously healthy and immunocompetent adult who developed meningitis, central skull base osteomyelitis, and occipital condylar cerebrospinal fluid rhinorrhea from CA-MRSA sphenoid sinusitis requiring endoscopic surgical repair. This case clearly demonstrates the expanding spectrum of severe infections caused by CA-MRSA, which requires prompt diagnosis, a high level of suspicion, and appropriate medical and/or surgical management. PMID:22447436

Tomovic, Senja; Friedel, Mark E; Liu, James K; Eloy, Jean Anderson

2012-05-01

388

Reconstruction of a large posterior scalp defect using occipital artery based pedicled island v-y advancement flap: a case report.  

PubMed

Repair of scalp defects using local hair bearing scalp is technically challenging. Transposition or rotation of local flaps to close the defect has its own disadvantages. Reconstruction of a large posterior scalp defect using occipital artery based pedicled V-Y advancement flap following the excision of a recurrent fibrolipoma of epicranial aponeurosis is reported here. It is possible to reconstruct the defect with hair bearing scalp in a single stage along with primary closure of the donor site using this technique. PMID:22942599

Sharma, Rohit; Sirohi, Deepika; Sinha, Ramen; Menon, P Suresh

2011-09-01

389

Preprint version of the paper published on Cortex, doi: 10.1016/j.cortex.2013.01.013 The anatomy of cerebral achromatopsia  

E-print Network

Preprint version of the paper published on Cortex, doi: 10.1016/j.cortex.2013.01.013 The anatomy of cerebral achromatopsia: A reappraisal and comparison of two case reports Paolo Bartolomeo1-3 , Anne-23Mar2013 Author manuscript, published in "Cortex 2013;:epub ahead of print" DOI : 10.1016/j.cortex.2013

Paris-Sud XI, Université de

390

GABA transporters in the mammalian cerebral cortex: localization, development and pathological implications  

E-print Network

Review GABA transporters in the mammalian cerebral cortex: localization, development-aminobutyric acid (GABA), the main inhibitory neurotransmitter in the mammalian cerebral cortex, are regulated-1 and -3 are expressed in the cerebral cortex. Studies of the cortical distribution, cellular

Sandini, Giulio

391

Insular Cortex Is Involved in Consolidation of Object Recognition Memory  

ERIC Educational Resources Information Center

Extensive evidence indicates that the insular cortex (IC), also termed gustatory cortex, is critically involved in conditioned taste aversion and taste recognition memory. Although most studies of the involvement of the IC in memory have investigated taste, there is some evidence that the IC is involved in memory that is not based on taste. In…

Bermudez-Rattoni, Federico; Okuda, Shoki; Roozendaal, Benno; McGaugh, James L.

2005-01-01

392

Cerebral Cortex doi:10.1093/cercor/bhm220  

E-print Network

Cerebral Cortex doi:10.1093/cercor/bhm220 Common Neural Substrates for Inhibition of Spoken of California, San Diego, CA 92093, USA The inhibition of speech acts is a critical aspect of human executive frontal cortex (IFC: Broca's area). Successful inhibition of speech (naming of letters or pseudo- words

Aron, Adam

393

Perception and Action Selection Dissociate Human Ventral and Dorsal Cortex  

E-print Network

Perception and Action Selection Dissociate Human Ventral and Dorsal Cortex Akiko Ikkai, Trenton A cortex by correlating brain activity with demands on per- ception versus action selection. Subjects covertly searched for a target among an array of 4, 8, or 12 items (perceptual manipula- tion) and then

Curtis, Clayton

394

Mapping the Structural Core of Human Cerebral Cortex  

Microsoft Academic Search

Structurally segregated and functionally specialized regions of the human cerebral cortex are interconnected by a dense network of cortico-cortical axonal pathways. By using diffusion spectrum imaging, we noninvasively mapped these pathways within and across cortical hemispheres in individual human participants. An analysis of the resulting large-scale structural brain networks reveals a structural core within posterior medial and parietal cerebral cortex,

Patric Hagmann; Leila Cammoun; Xavier Gigandet; Reto Meuli; Christopher J. Honey; Van J. Wedeen; Olaf Sporns

2008-01-01

395

Mapping Striate and Extrastriate Visual Areas in Human Cerebral Cortex  

Microsoft Academic Search

Functional magnetic resonance imaging (fMRI) was used to identify and map the representation of the visual field in seven areas of human cerebral cortex and to identify at least two additional visually responsive regions. The cortical locations of neurons responding to stimulation along the vertical or horizontal visual field meridia were charted on three-dimensional models of the cortex and on

Edgar A. Deyoe; George J. Carman; Peter Bandettini; Seth Glickman; Jon Wieser; Robert Cox; David Miller; Jay Neitz

1996-01-01

396

Electrophysiological indices of sleep in the cerebral cortex  

NASA Technical Reports Server (NTRS)

An electrophysiological investigation of the nerve structures in which sleep inhibition develops is discussed. Twenty-four points of the cat's brain were selected for recordings. It was found that the anterior cortex produced delta waves in the initial period of sleep. The waves subsequently spread over the entire cortex. Subsequent investigation reveals similar facts pertinent to other waves in subsequent stages.

Kogan, A. B.; Feldman, G. L.

1973-01-01

397

Cerebral Cortex doi:10.1093/cercor/bhr228  

E-print Network

of Motor Cortex in Squirrels Dylan F. Cooke1 , Jeffrey Padberg2 , Tony Zahner1,3 and Leah Krubitzer1,3 1 squirrel (Sciurus carolinensis) and cortical connec- tions of motor cortex in the California ground squirrel (Spermophi- lus beecheyi). We distinguish a primary motor area, M1, based on intracortical

Krubitzer, Leah A.

398

Motor Cortex Andrew B. Schwartz and Steven P. Wise  

E-print Network

a major input from the ventrolateral thalamus, which relays information from the cerebellum and basal cerebellar nuclei, particularly the dentate and interpositus nuclei (via the thalamus), the internal segment of the globus pallidus (also via the thalamus), the somatosensory cortex, part of the posterior parietal cortex

Schwartz, Andrew

399

Cerebral Cortex doi:10.1093/cercor/bhs068  

E-print Network

, hypnosis, memory systems, prefrontal cortex, sequence learning, striatum Introduction Human learningCerebral Cortex doi:10.1093/cercor/bhs068 Boosting Human Learning by Hypnosis Dezso Nemeth1 6722, Hungary. Email: nemethd@edpsy.u-szeged.hu. Human learning and memory depend on multiple cognitive

Nemeth, Dezso

400

Discourse Production Following Injury to the Dorsolateral Prefrontal Cortex  

ERIC Educational Resources Information Center

Individuals with damage to the prefrontal cortex, and the dorsolateral prefrontal cortex (DLPFC) in particular, often demonstrate difficulties with the formulation of complex language not attributable to aphasia. The present study employed a discourse analysis procedure to characterize the language of individuals with left (L) or right (R) DLPFC…

Coelho, Carl; Le, Karen; Mozeiko, Jennifer; Krueger, Frank; Grafman, Jordan

2012-01-01

401

Abnormal Asymmetry in Language Association Cortex in Autism  

E-print Network

Abnormal Asymmetry in Language Association Cortex in Autism Martha R. Herbert, MD, PhD,1 Gordon J Masanori Takeoka, MD,7 Helen Tager-Flusberg, PhD,4 and Verne S. Caviness, Jr., MD1 Autism- related cortex in autistic and control subjects. Subjects included 16 boys with autism (aged 7­11 years

Chabris, Christopher F.

402

Activity in Prelimbic Cortex Subserves Fear Memory Reconsolidation over Time  

ERIC Educational Resources Information Center

The prelimbic cortex has been implicated in the consolidation of previously learned fear. Herein, we report that temporarily inactivating this medial prefrontal cortex subregion with the GABA [subscript A] agonist muscimol (4.0 nmol in 0.2 µL per hemisphere) was able to equally disrupt 1-, 7-, and 21-d-old contextual fear memories after their…

Stern, Cristina A. J.; Gazarini, Lucas; Vanvossen, Ana C.; Hames, Mayara S.; Bertoglio, Leandro J.

2014-01-01

403

Medial Prefrontal Cortex Lesions Abolish Contextual Control of Competing Responses  

ERIC Educational Resources Information Center

There is much debate as to the extent and nature of functional specialization within the different subregions of the prefrontal cortex. The current study was undertaken to investigate the effect of damage to medial prefrontal cortex subregions in the rat. Rats were trained on two biconditional discrimination tasks, one auditory and one visual, in…

Haddon, J. E.; Killcross, A. S.

2005-01-01

404

Chronic Stress Alters Dendritic Morphology in Rat Medial Prefrontal Cortex  

E-print Network

Chronic Stress Alters Dendritic Morphology in Rat Medial Prefrontal Cortex Susan C. Cook,1 Cara L ABSTRACT: Chronic stress produces deficits in cognition accompanied by alterations in neural chemis- try and morphology. Medial prefrontal cortex is a target for glucocorticoids involved in the stress response. We have

Wellman, Cara

405

The Hyper-Cortex of Human Collective-Intelligence Systems  

Microsoft Academic Search

Individual-intelligence research, from a neurological perspective, discusses the hierarchical layers of the cortex as a structure that performs conceptual abstraction and specification. This theory has been used to explain how motor-cortex regions responsible for different behavioral modalities such as writing and speaking can be utilized to express the same general concept represented higher in the cortical hierarchy. For example, the

Marko A. Rodriguez

2005-01-01

406

Selective Attention Gates Visual Processing in the Extrastriate Cortex  

Microsoft Academic Search

Single cells were recorded in the visual cortex of monkeys trained to attend to stimuli at one location in the visual field and ignore stimuli at another. When both locations were within the receptive field of a cell in prestriate area V4 or the inferior temporal cortex, the response to the unattended stimulus was dramatically reduced. Cells in the striate

Jeffrey Moran; Robert Desimone

1985-01-01

407

Target Motion Discrimination with Model Retina and Cortex  

E-print Network

. . . . . . . . . .. . . Target Motion Discrimination with Model Retina and Cortex Maha. A. P Masters of Science in Mathematics - Thesis DefenseTarget Motion Discrimination with Model Retina of Science in Mathematics - Thesis DefenseTarget Motion Discrimination with Model Retina and Cortex #12

Ghosh, Bijoy K.

408

Metaphorically Feeling: Comprehending Textural Metaphors Activates Somatosensory Cortex  

ERIC Educational Resources Information Center

Conceptual metaphor theory suggests that knowledge is structured around metaphorical mappings derived from physical experience. Segregated processing of object properties in sensory cortex allows testing of the hypothesis that metaphor processing recruits activity in domain-specific sensory cortex. Using functional magnetic resonance imaging…

Lacey, Simon; Stilla, Randall; Sathian, K.

2012-01-01

409

Stimulus rate dependence of regional cerebral blood flow in human striate cortex, demonstrated by positron emission tomography  

SciTech Connect

The purpose of this investigation was to determine the relationship between the repetition rate of a simple sensory stimulus and regional cerebral blood flow (rCBF) in the human brain. Positron emission tomography (PET), using intravenously administered H/sub 2/(/sup 15/)O as the diffusible blood-flow tracer, was employed for all CBF measurements. The use of H/sub 2/(/sup 15/)O with PET allowed eight CBF measurements to be made in rapid sequence under multiple stimulation conditions without removing the subject from the tomograph. Nine normal volunteers each underwent a series of eight H2(/sup 15/)O PET measurements of CBF. Initial and final scans were made during visual deprivation. The six intervening scans were made during visual activation with patterned-flash stimuli given in random order at 1.0-, 3.9-, 7.8-, 15.5-, 33.1-, and 61-Hz repetition rates. The region of greatest rCBF increase was determined. Within this region the rCBF was determined for every test condition and then expressed as the percentage change from the value of the initial unstimulated scan (rCBF% delta). In every subject, striate cortex rCBF% delta varied systematically with stimulus rate. Between 0 and 7.8 Hz, rCBF% delta was a linear function of stimulus repetition rate. The rCBF response peaked at 7.8 Hz and then declined. The rCBF% delta during visual stimulation was significantly greater than that during visual deprivation for every stimulus rate except 1.0 Hz. The anatomical localization of the region of peak rCBF response was determined for every subject to be the mesial occipital lobes along the calcarine fissure, primary visual cortex. Stimulus rate is a significant determinant of rCBF response in the visual cortex. Investigators of brain responses to selective activation procedures should be aware of the potential effects of stimulus rate on rCBF and other measurements of cerebral metabolism.

Fox, P.T.; Raichle, M.E.

1984-05-01

410

Functional and structural correlates of the aging brain: Relating visual cortex (V1) gamma band responses to age-related structural change  

PubMed Central

The gamma band response is thought to be a key neural signature of information processing in the mammalian brain, yet little is known about how age-related maturation influences the gamma-band response. Recent MRI based studies have shown that brain maturation is accompanied by clear structural changes in both grey and white matter, yet the correspondence of these changes to brain function is unclear. The objective of this study was to relate visual cortex (V1) gamma-band responses to age-related structural change. We evaluated MEG measured gamma-band responses to contrast gratings stimuli and structural MRIs from participants observed from 2 separate research centers (MEG lab at CUBRIC, Cardiff University, UK, and the Lurie Family Foundations MEG Imaging Center, (CHOP) at the Children’s Hospital of Philadelphia). Pooled participant data (N=59) ranged in age from 8.7 to 45.3 yrs. We assessed linear associations between age and MEG gamma-band frequency and amplitude, as well as between age and MRI volumetric parameters of the occipital lobe. Our MEG findings revealed a significant negative correlation for gamma band frequency vs. age. Volumetric brain analysis from the occipital lobe also revealed significant negative correlations between age and the cortical thickness of pericalcarine and cuneus areas. Our functional MEG and structural MRI findings shows regionally specific changes due to maturation and may thus be informative for understanding physiological processes of neural development, maturation, and age-related decline. In addition, this study represents (to our knowledge), the first published demonstration of multi-centre data sharing across MEG centers. PMID:21769992

Gaetz, W.; Roberts, T.P.L.; Singh, K. D.; Muthukumaraswamy, S.D.

2011-01-01

411

Mimicking the mechanical properties of the cell cortex by the self-assembly of an actin cortex in vesicles  

E-print Network

Mimicking the mechanical properties of the cell cortex by the self-assembly of an actin cortex Table of Contents: http://scitation.aip.org/content/aip/journal/apl/104/15?ver=pdfcov Published.1116/1.2167979 This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http

Robinson, Douglas N.

412

Effects of unilateral deactivations of dorsolateral prefrontal cortex and anterior cingulate cortex on saccadic eye movements.  

PubMed

The dorsolateral prefrontal cortex (dlPFC) and anterior cingulate cortex (ACC) have both been implicated in the cognitive control of saccadic eye movements by single neuron recording studies in nonhuman primates and functional imaging studies in humans, but their relative roles remain unclear. Here, we reversibly deactivated either dlPFC or ACC subregions in macaque monkeys while the animals performed randomly interleaved pro- and antisaccades. In addition, we explored the whole-brain functional connectivity of these two regions by applying a seed-based resting-state functional MRI analysis in a separate cohort of monkeys. We found that unilateral dlPFC deactivation had stronger behavioral effects on saccades than unilateral ACC deactivation, and that the dlPFC displayed stronger functional connectivity with frontoparietal areas than the ACC. We suggest that the dlPFC plays a more prominent role in the preparation of pro- and antisaccades than the ACC. PMID:24285866

Koval, Michael J; Hutchison, R Matthew; Lomber, Stephen G; Everling, Stefan

2014-02-01

413

Cerebral blood flow modeling in primate cortex  

PubMed Central

We report new results on blood flow modeling over large volumes of cortical gray matter of primate brain. We propose a network method for computing the blood flow, which handles realistic boundary conditions, complex vessel shapes, and complex nonlinear blood rheology. From a detailed comparison of the available models for the blood flow rheology and the phase separation effect, we are able to derive important new results on the impact of network structure on blood pressure, hematocrit, and flow distributions. Our findings show that the network geometry (vessel shapes and diameters), the boundary conditions associated with the arterial inputs and venous outputs, and the effective viscosity of the blood are essential components in the flow distribution. In contrast, we show that the phase separation effect has a minor function in the global microvascular hemodynamic behavior. The behavior of the pressure, hematocrit, and blood flow distributions within the network are described through the depth of the primate cerebral cortex and are discussed. PMID:20648040

Guibert, Romain; Fonta, Caroline; Plouraboue, Franck

2010-01-01

414

Contrast Gain Control in Auditory Cortex  

PubMed Central

Summary The auditory system must represent sounds with a wide range of statistical properties. One important property is the spectrotemporal contrast in the acoustic environment: the variation in sound pressure in each frequency band, relative to the mean pressure. We show that neurons in ferret auditory cortex rescale their gain to partially compensate for the spectrotemporal contrast of recent stimulation. When contrast is low, neurons increase their gain, becoming more sensitive to small changes in the stimulus, although the effectiveness of contrast gain control is reduced at low mean levels. Gain is primarily determined by contrast near each neuron's preferred frequency, but there is also a contribution from contrast in more distant frequency bands. Neural responses are modulated by contrast over timescales of ?100 ms. By using contrast gain control to expand or compress the representation of its inputs, the auditory system may be seeking an efficient coding of natural sounds. PMID:21689603

Rabinowitz, Neil C.; Willmore, Ben D.B.; Schnupp, Jan W.H.; King, Andrew J.

2011-01-01

415

Diffeomorphic Sulcal Shape Analysis on the Cortex  

PubMed Central

We present a diffeomorphic approach for constructing intrinsic shape atlases of sulci on the human cortex. Sulci are represented as square-root velocity functions of continuous open curves in ?3, and their shapes are studied as functional representations of an infinite-dimensional sphere. This spherical manifold has some advantageous properties – it is equipped with a Riemannian metric on the tangent space and facilitates computational analyses and correspondences between sulcal shapes. Sulcal shape mapping is achieved by computing geodesics in the quotient space of shapes modulo scales, translations, rigid rotations and reparameterizations. The resulting sulcal shape atlas preserves important local geometry inherently present in the sample population. The sulcal shape atlas is integrated in a cortical registration framework and exhibits better geometric matching compared to the conventional euclidean method. We demonstrate experimental results for sulcal shape mapping, cortical surface registration, and sulcal classification for two different surface extraction protocols for separate subject populations. PMID:22328177

Joshi, Shantanu H.; Cabeen, Ryan P.; Joshi, Anand A.; Sun, Bo; Dinov, Ivo; Narr, Katherine L.; Toga, Arthur W.; Woods, Roger P.

2014-01-01

416

Lateral prefrontal cortex contributes to maladaptive decisions  

PubMed Central

Humans consistently make suboptimal decisions involving random events, yet the underlying neural mechanisms remain elusive. Using functional MRI and a matching pennies game that captured subjects’ increasing tendency to predict the break of a streak as it continued [i.e., the “gambler's fallacy” (GF)], we found that a strong blood oxygen level-dependent response in the left lateral prefrontal cortex (LPFC) to the current outcome preceded the use of the GF strategy 10 s later. Furthermore, anodal transcranial direct current stimulation over the left LPFC, which enhances neuronal firing rates and cerebral excitability, increased the use of the GF strategy, and made the decisions more “sticky.” These results reveal a causal role of the LPFC in implementing suboptimal decision strategy guided by false world models, especially when such strategy requires great resources for cognitive control. PMID:22393013

Xue, Gui; Juan, Chi-Hung; Chang, Chi-Fu; Lu, Zhong-Lin; Dong, Qi

2012-01-01

417

Social error monitoring in macaque frontal cortex.  

PubMed

Although much learning occurs through direct experience of errors, humans and other animals can learn from the errors of other individuals. The medial frontal cortex (MFC) processes self-generated errors, but the neuronal architecture and mechanisms underlying the monitoring of others' errors are poorly understood. Exploring such mechanisms is important, as they underlie observational learning and allow adaptive behavior in uncertain social environments. Using two paired monkeys that monitored each other's action for their own action selection, we identified a group of neurons in the MFC that exhibited a substantial activity increase that was associated with another's errors. Nearly half of these neurons showed activity changes consistent with general reward-omission signals, whereas the remaining neurons specifically responded to another's erroneous actions. These findings indicate that the MFC contains a dedicated circuit for monitoring others' mistakes during social interactions. PMID:22864610

Yoshida, Kyoko; Saito, Nobuhito; Iriki, Atsushi; Isoda, Masaki

2012-09-01

418

A new method for automated high-dimensional lesion segmentation evaluated in vascular injury and applied to the human occipital lobe.  

PubMed

Making robust inferences about the functional neuroanatomy of the brain is critically dependent on experimental techniques that examine the consequences of focal loss of brain function. Unfortunately, the use of the most comprehensive such technique-lesion-function mapping-is complicated by the need for time-consuming and subjective manual delineation of the lesions, greatly limiting the practicability of the approach. Here we exploit a recently-described general measure of statistical anomaly, zeta, to devise a fully-automated, high-dimensional algorithm for identifying the parameters of lesions within a brain image given a reference set of normal brain images. We proceed to evaluate such an algorithm in the context of diffusion-weighted imaging of the commonest type of lesion used in neuroanatomical research: ischaemic damage. Summary performance metrics exceed those previously published for diffusion-weighted imaging and approach the current gold standard-manual segmentation-sufficiently closely for fully-automated lesion-mapping studies to become a possibility. We apply the new method to 435 unselected images of patients with ischaemic stroke to derive a probabilistic map of the pattern of damage in lesions involving the occipital lobe, demonstrating the variation of anatomical resolvability of occipital areas so as to guide future lesion-function studies of the region. PMID:23347558

Mah, Yee-Haur; Jager, Rolf; Kennard, Christopher; Husain, Masud; Nachev, Parashkev

2014-07-01

419

The post-occipital spinal venous sinus of the Nile crocodile Crocodylus niloticus: its anatomy and use for blood sample collection and intravenous infusions.  

PubMed

The post-occipital sinus of the spinal vein is often used for the collection of blood samples from crocodilians. Although this sampling method has been reported for several crocodilian species, the technique and associated anatomy has not been described in detail in any crocodilian, including the Nile crocodile (Crocodylus niloticus). The anatomy of the cranial neck region was investigated macroscopically, microscopically, radiographically and by means of computed tomography. Latex was injected into the spinal vein and spinal venous sinus of crocodiles to visualise the regional vasculature. The spinal vein ran within the vertebral canal, dorsal to and closely associated with the spinal cord and changed into a venous sinus cranially in the post-occipital region. For blood collection, the spinal venous sinus was accessed through the interarcuate space between the atlas and axis (C1 and C2) by inserting a needle angled just off the perpendicular in the midline through the craniodorsal cervical skin, just cranial to the cranial borders of the first cervical osteoderms. The most convenient method of blood collection was with a syringe and hypodermic needle. In addition, the suitability of the spinal venous sinus for intravenous injections and infusions in live crocodiles was evaluated. The internal diameter of the commercial human epidural catheters used during these investigations was relatively small, resulting in very slow infusion rates. Care should be taken not to puncture the spinal cord or to lacerate the blood vessel wall using this route for blood collection or intravenous infusions. PMID:24831995

Myburgh, Jan G; Kirberger, Robert M; Steyl, Johan C A; Soley, John T; Booyse, Dirk G; Huchzermeyer, Fritz W; Lowers, Russel H; Guillette, Louis J

2014-01-01

420

Age estimation using CT imaging of the third molar tooth, the medial clavicular epiphysis, and the spheno-occipital synchondrosis: a multifactorial approach.  

PubMed

A multi-factorial method for estimating age was devised based on the development of the 3rd molar tooth, the medial clavicular epiphysis, and the spheno-occipital synchondrosis, using multiple regression as the means to construct age estimation formulae and CT scanning as the imaging modality. The sample consisted of approximately 600 individuals from a contemporary Australian population, between the ages of 15 and 25 years, who were admitted to the Victorian Institute of Forensic Medicine, Melbourne, Australia, for the purposes of medico-legal death investigation. Results show that the spheno-occipital synchondrosis does not contribute to the age estimation model for this age cohort. The regression computation for the 3rd molar tooth and medial clavicle, when combined into a single multiple regression calculation, provides a robust model with tighter age ranges at the 95% confidence interval (CI) than when each age marker is used individually. This research provides a method to estimate age for unknown age Australian individuals in the problematic age group of 15-25 years with greater precision than previously possible. PMID:21723055

Bassed, Richard B; Briggs, Christopher; Drummer, Olaf H

2011-10-10

421

A new method for automated high-dimensional lesion segmentation evaluated in vascular injury and applied to the human occipital lobe  

PubMed Central

Making robust inferences about the functional neuroanatomy of the brain is critically dependent on experimental techniques that examine the consequences of focal loss of brain function. Unfortunately, the use of the most comprehensive such technique—lesion-function mapping—is complicated by the need for time-consuming and subjective manual delineation of the lesions, greatly limiting the practicability of the approach. Here we exploit a recently-described general measure of statistical anomaly, zeta, to devise a fully-automated, high-dimensional algorithm for identifying the parameters of lesions within a brain image given a reference set of normal brain images. We proceed to evaluate such an algorithm in the context of diffusion-weighted imaging of the commonest type of lesion used in neuroanatomical research: ischaemic damage. Summary performance metrics exceed those previously published for diffusion-weighted imaging and approach the current gold standard—manual segmentation—sufficiently closely for fully-automated lesion-mapping studies to become a possibility. We apply the new method to 435 unselected images of patients with ischaemic stroke to derive a probabilistic map of the pattern of damage in lesions involving the occipital lobe, demonstrating the variation of anatomical resolvability of occipital areas so as to guide future lesion-function studies of the region. PMID:23347558

Mah, Yee-Haur; Jager, Rolf; Kennard, Christopher; Husain, Masud; Nachev, Parashkev

2014-01-01

422

TMS-induced neural noise in sensory cortex interferes with short-term memory storage in prefrontal cortex  

PubMed Central

In a previous study, Harris et al. (2002) found disruption of vibrotactile short-term memory after applying single-pulse transcranial magnetic stimulation (TMS) to primary somatosensory cortex (SI) early in the maintenance period, and suggested that this demonstrated a role for SI in vibrotactile memory storage. While such a role is compatible with recent suggestions that sensory cortex is the storage substrate for working memory, it stands in contrast to a relatively large body of evidence from human EEG and single-cell recording in primates that instead points to prefrontal cortex as the storage substrate for vibrotactile memory. In the present study, we use computational methods to demonstrate how Harris et al.'s results can be reproduced by TMS-induced activity in sensory cortex and subsequent feedforward interference with memory traces stored in prefrontal cortex, thereby reconciling discordant findings in the tactile memory literature. PMID:24634653

Bancroft, Tyler D.; Hogeveen, Jeremy; Hockley, William E.; Servos, Philip

2014-01-01

423

METAPHORICALLY FEELING: COMPREHENDING TEXTURAL METAPHORS ACTIVATES SOMATOSENSORY CORTEX  

PubMed Central

Conceptual metaphor theory suggests that knowledge is structured around metaphorical mappings derived from physical experience. Segregated processing of object properties in sensory cortex allows testing of the hypothesis that metaphor processing recruits activity in domain-specific sensory cortex. Using functional magnetic resonance imaging (fMRI) we show that texture-selective somatosensory cortex in the parietal operculum is activated when processing sentences containing textural metaphors, compared to literal sentences matched for meaning. This finding supports the idea that comprehension of metaphors is perceptually grounded. PMID:22305051

Lacey, Simon; Stilla, Randall; Sathian, K.

2012-01-01

424

The myeloarchitectonic studies on the human cerebral cortex of the Vogt-Vogt school, and their significance for the interpretation of functional neuroimaging data.  

PubMed

The human cerebral cortex contains numerous myelinated fibres, many of which are concentrated in tangentially organized layers and radially oriented bundles. The spatial organization of these fibres is by no means homogeneous throughout the cortex. Local differences in the thickness and compactness of the fibre layers, and in the length and strength of the radial bundles renders it possible to recognize areas with a different myeloarchitecture. The neuroanatomical subdiscipline aimed at the identification and delineation of such areas is known as myeloarchitectonics. There is another, closely related neuroanatomical subdiscipline, named cytoarchitectonics. The aims and scope of this subdiscipline are the same as those of myeloarchitectonics, viz. parcellation. However, this subdiscipline focuses, as its name implies, on the size, shape and arrangement of the neuronal cell bodies in the cortex, rather than on the myelinated fibres. At the beginning of the twentieth century, two young investigators, Oskar and Cécile Vogt founded a centre for brain research, aimed to be devoted to the study of the (cyto + myelo) architecture of the cerebral cortex. The study of the cytoarchitecture was entrusted to their collaborator Korbinian Brodmann, who gained great fame with the creation of a cytoarchitectonic map of the human cerebral cortex. Here, we focus on the myeloarchitectonic studies on the cerebral cortex of the Vogt-Vogt school, because these studies are nearly forgotten in the present attempts to localize functional activations and to interprete findings in modern neuroimaging studies. Following introductory sections on the principles of myeloarchitectonics, and on the achievements of three myeloarchitectonic pioneers who did not belong to the Vogt-Vogt school, the pertinent literature is reviewed in some detail. These studies allow the conclusion that the human neocortex contains about 185 myeloarchitectonic areas, 70 frontal, 6 insular, 30 parietal, 19 occipital, and 60 temporal. It is emphasized that the data available, render it possible to compose a myeloarchitectonic map of the human neocortex, which is at least as reliable as any of the classic architectonic maps. During the realization of their myeloarchitectonic research program, in which numerous able collaborators were involved, the Vogts gradually developed a general concept of the organization of the cerebral cortex. The essence of this concept is that this structure is composed of about 200 distinct, juxtaposed 'Rindenfelder' or 'topistische Einheiten', which represent fundamental structural as well as functional entities. The second main part of this article is devoted to a discussion and evaluation of this 'Vogt-Vogt concept'. It is concluded that there is converging quantitative cytoarchitectonic, receptor architectonic, myeloarchitectonic, hodological, and functional evidence, indicating that this concept is essentially correct. The third, and final part of this article deals with the problem of relating particular cortical functions, as determined with neuroimaging techniques, to particular cortical structures. At present, these 'translation' operations are generally based on adapted, three-dimensional versions of Brodmann's famous map. However, it has become increasingly clear that these maps do not provide the neuroanatomical precision to match the considerable degree of functional segregation, suggested by neuroimaging studies. Therefore, we strongly recommend an attempt at combining and synthesizing the results of Brodmann's cytoarchitectonic analysis, with those of the detailed myeloarchitectonic studies of the Vogt-Vogt school. These studies may also be of interest for the interpretation of the myeloarchitectonic features, visualized in modern in vivo mappings of the human cortex. PMID:23076375

Nieuwenhuys, Rudolf

2013-03-01

425

A systems approach to orbitofrontal cortex function: recordings in rat orbitofrontal cortex reveal interactions with different learning systems.  

PubMed

The recognition that certain aspects of prefrontal function can be effectively modeled in rats has led to a slow expansion of interest in rat prefrontal cortex over the past decade. One of the most promising of these model systems is the orbitofrontal cortex of the rat. Rat orbitofrontal cortex is anatomically similar to the orbital prefrontal region in primates, and this similarity is borne out by behavioral and neurophysiological findings. Here we will present data on orbitofrontal cortex function from a number of parallel studies from our laboratories that employed single unit recording techniques to probe neural encoding in rat orbitofrontal cortex and related parts of the amygdala and the hippocampal memory systems. Together, these reports and associated behavioral studies suggest that the orbitofrontal region, in both rats and primates, is specialized to integrate concrete and abstract sensory constructs with information regarding the incentive value of associated outcomes to guide or modulate behavior. To the extent that monkey prefrontal function can model certain aspects of human prefrontal function, we argue that this model can now be extended to the rat orbitofrontal cortex. In addition, we argue that the function of orbitofrontal cortex needs to be considered in terms of its interactions with other brain systems. PMID:14643456

Schoenbaum, Geoffrey; Setlow, Barry; Ramus, Seth J

2003-11-30

426

The spatiotopic 'visual' cortex of the blind  

NASA Astrophysics Data System (ADS)

Visual cortex activity in the blind has been shown in sensory tasks. Can it be activated in memory tasks? If so, are inherent features of its organization meaningfully employed? Our recent results in short-term blindfolded subjects imply that human primary visual cortex (V1) may operate as a modality-independent 'sketchpad' for working memory (Likova, 2010a). Interestingly, the spread of the V1 activation approximately corresponded to the spatial extent of the images in terms of their angle of projection to the subject. We now raise the questions of whether under long-term visual deprivation V1 is also employed in non-visual memory task, in particular in congenitally blind individuals, who have never had visual stimulation to guide the development of the visual area organization, and whether such spatial organization is still valid for the same paradigm that was used in blindfolded individuals. The outcome has implications for an emerging reconceptualization of the principles of brain architecture and its reorganization under sensory deprivation. Methods: We used a novel fMRI drawing paradigm in congenitally and late-onset blind, compared with sighted and blindfolded subjects in three conditions of 20s duration, separated by 20s rest-intervals, (i) Tactile Exploration: raised-line images explored and memorized; (ii) Tactile Memory Drawing: drawing the explored image from memory; (iii) Scribble: mindless drawing movements with no memory component. Results and Conclusions: V1 was strongly activated for Tactile Memory Drawing and Tactile Exploration in these totally blind subjects. Remarkably, after training, even in the memory task, the mapping of V1 activation largely corresponded to the angular projection of the tactile stimuli relative to the ego-center (i.e., the effective visual angle at the head); beyond this projective boundary, peripheral V1 signals were dramatically reduced or even suppressed. The matching extent of the activation in the congenitally blind rules out vision-based explanatory mechanisms, and supports the more radical idea of V1 as a modality-independent 'projection screen' or a 'sketchpad', whose mapping scales to the projective dimensions of objects explored in the peri-personal space.

Likova, Lora

2012-03-01

427

Evolution of the cerebellar cortex: The selective expansion of prefrontal-projecting cerebellar lobules  

Microsoft Academic Search

It has been suggested that interconnected brain areas evolve in tandem because evolutionary pressures act on complete functional systems rather than on individual brain areas. The cerebellar cortex has reciprocal connections with both the prefrontal cortex and motor cortex, forming independent loops with each. Specifically, in capuchin monkeys cerebellar cortical lobules Crus I and Crus II connect with prefrontal cortex,

J. H. Balsters; E. Cussans; J. Diedrichsen; K. A. Phillips; T. M. Preuss; J. K. Rilling; N. Ramnani

2010-01-01

428

Cerebral Cortex August 2011;21:1935--1940 doi:10.1093/cercor/bhq270  

E-print Network

Cerebral Cortex August 2011;21:1935--1940 doi:10.1093/cercor/bhq270 Advance Access publication January 12, 2011 Misconceptions about Mirror-Induced Motor Cortex Activation Peter Praamstra1,2 , Laura, was recently reported to induce ipsilateral motor cortex activation, that is, motor cortex activation

Miall, Chris

429

Adaptation of the Generalized Carnot Cycle to Describe Thermodynamics of Cerebral Cortex  

E-print Network

Adaptation of the Generalized Carnot Cycle to Describe Thermodynamics of Cerebral Cortex Freeman to describe thermodynamics of cerebral cortex. Proc IEEE World Congr Comp Intell WCCI sensory cortex condenses from a gas-like state to a liquid-like state. It ends with return of the cortex

Freeman, Walter J.

430

Models of Networks of Neurons Neurons are organized in large networks. A typical neuron is cortex  

E-print Network

cell. These are the primary excitatory neurons of the cerebral cortex. Pyramidal cell axons branch. Purkinje cell axons transmit the output of the cerebellar cortex. C) A stellate cell of the cerebral cortex) A stellate cell of the cerebral cortex. Stellate cells are one of a large class of cells that provide

Seriès, Peggy

431

Cerebral Cortex July 2008;18:1549--1559 doi:10.1093/cercor/bhm185  

E-print Network

Cerebral Cortex July 2008;18:1549--1559 doi:10.1093/cercor/bhm185 Advance Access publication) in the orbitofrontal cortex were modulated by word-level descriptors. Affect-related activations to taste were modulated in a region that receives from the orbitofrontal c