scholarly journals Interhemispheric synchrony in occipital cortex predicts mnemonic precision in working memory

2013 ◽  
Vol 13 (9) ◽  
pp. 16-16
Author(s):  
D. E. Anderson ◽  
E. K. Vogel ◽  
E. Awh
Keyword(s):  
Working Memory ◽  
Occipital Cortex ◽  
Mnemonic Precision

scholarly journals Occipital Cortex of Blind Individuals Is Functionally Coupled with Executive Control Areas of Frontal Cortex

2015 ◽  
Vol 27 (8) ◽  
pp. 1633-1647 ◽  
Author(s):  
Ben Deen ◽  
Rebecca Saxe ◽  
Marina Bedny
Keyword(s):  
Working Memory ◽  
Functional Connectivity ◽  
Sentence Comprehension ◽  
Memory Load ◽  
Memory Task ◽  
Occipital Cortex ◽  
Memory Systems ◽  
Functional Responses ◽  
Congenitally Blind ◽  
Blind Individuals

In congenital blindness, the occipital cortex responds to a range of nonvisual inputs, including tactile, auditory, and linguistic stimuli. Are these changes in functional responses to stimuli accompanied by altered interactions with nonvisual functional networks? To answer this question, we introduce a data-driven method that searches across cortex for functional connectivity differences across groups. Replicating prior work, we find increased fronto-occipital functional connectivity in congenitally blind relative to blindfolded sighted participants. We demonstrate that this heightened connectivity extends over most of occipital cortex but is specific to a subset of regions in the inferior, dorsal, and medial frontal lobe. To assess the functional profile of these frontal areas, we used an n-back working memory task and a sentence comprehension task. We find that, among prefrontal areas with overconnectivity to occipital cortex, one left inferior frontal region responds to language over music. By contrast, the majority of these regions responded to working memory load but not language. These results suggest that in blindness occipital cortex interacts more with working memory systems and raise new questions about the function and mechanism of occipital plasticity.

scholarly journals Delay-period activity in frontal, parietal, and occipital cortex tracks noise and biases in visual working memory

PLoS Biology ◽  
2020 ◽  
Vol 18 (9) ◽  
pp. e3000854 ◽  
Author(s):  
Qing Yu ◽  
Matthew F. Panichello ◽  
Ying Cai ◽  
Bradley R. Postle ◽  
Timothy J. Buschman
Keyword(s):  
Working Memory ◽  
Visual Working Memory ◽  
Occipital Cortex ◽  
Delay Period

Working memory training in congenitally blind individuals results in an integration of occipital cortex in functional networks

2018 ◽  
Vol 348 ◽  
pp. 31-41 ◽  
Author(s):  
Helene Gudi-Mindermann ◽  
Johanna M. Rimmele ◽  
Guido Nolte ◽  
Patrick Bruns ◽  
Andreas K. Engel ◽  
...  
Keyword(s):  
Working Memory ◽  
Occipital Cortex ◽  
Working Memory Training ◽  
Memory Training ◽  
Functional Networks ◽  
Congenitally Blind ◽  
Blind Individuals

Insights into visual working memory precision at the feature- and object-level from a hemispheric encoding manipulation

2020 ◽  
Vol 73 (11) ◽  
pp. 1949-1968
Author(s):  
Elena M Galeano Weber ◽  
Haley Keglovits ◽  
Arin Fisher ◽  
Silvia A Bunge
Keyword(s):  
Working Memory ◽  
Visual Working Memory ◽  
Right Hemisphere ◽  
Single Object ◽  
Mnemonic Precision ◽  
Parallel Feature ◽  
Spatial Size ◽  
Memory Precision ◽  
Distinct Features ◽  
Object Level

Mnemonic precision is an important aspect of visual working memory (WM). Here, we probed mechanisms that affect precision for spatial (size) and non-spatial (colour) features of an object, and whether these features are encoded and/or stored separately in WM. We probed precision at the feature-level—that is, whether different features of a single object are represented separately or together in WM—and the object-level—that is, whether different features across a set of sequentially presented objects are represented in the same or different WM stores. By manipulating whether stimuli were encoded by the left and/or right hemisphere, we gained further insights into how objects are represented in WM. At the feature-level, we tested whether recall fidelity for the two features of an object fluctuated in tandem from trial to trial. We observed no significant coupling under either central or lateralized encoding, supporting the claim of parallel feature channels at encoding. At the level of WM storage of a set of objects, we found asymmetric feature interference under central encoding, whereby an increase in colour load led to a decrease in size precision. When objects were encoded by a single hemisphere, however, we found largely independent feature stores. Precision for size was more resistant to interference from the size of another object under right-hemisphere encoding; by contrast, precision for colour did not differ across hemispheres, suggesting a more distributed WM store. These findings suggest that distinct features of a single object are represented separately but are then partially integrated during maintenance of a set of sequentially presented objects.

Schizotypy is associated with reduced mnemonic precision in visual working memory

2018 ◽  
Vol 193 ◽  
pp. 91-97 ◽  
Author(s):  
Weizhen Xie ◽  
Marcus Cappiello ◽  
Hyung-Bum Park ◽  
Patricia Deldin ◽  
Raymond C.K. Chan ◽  
...  
Keyword(s):  
Working Memory ◽  
Visual Working Memory ◽  
Mnemonic Precision

scholarly journals Non-invasive Brain Stimulation Modulates GABAergic Activity in Neurofibromatosis 1

2021 ◽  
Author(s):  
Shruti Garg ◽  
Steve Williams ◽  
JeYoung Jung ◽  
Gorana Pobric ◽  
Tulika Nandi ◽  
...  
Keyword(s):  
Working Memory ◽  
Response Times ◽  
Single Gene ◽  
Occipital Cortex ◽  
Autism Spectrum ◽  
Neurofibromatosis 1 ◽  
Resonance Spectroscopy ◽  
Left Dlpfc ◽  
Promising Therapeutic Approach ◽  
Dorsolateral Prefrontal

Abstract Neurofibromatosis 1 (NF1) is a single-gene disorder associated with cognitive phenotypes common to neurodevelopmental conditions such as Autism Spectrum Disorder (ASD) & Attention Deficit Hyperactivity Disorder (ADHD). GABAergic dysregulation underlies working memory impairments seen in NF1. This mechanistic experimental study investigates whether application of anodal transcranial direct current stimulation (atDCS) can modulate GABA and working memory in NF1. 31 adolescents with NF1 were recruited to this single-blind sham-controlled cross-over randomized trial. Active or sham tDCS was applied to the left Dorsolateral Prefrontal Cortex (DLPFC) and Magnetic Resonance Spectroscopy was collected before and after intervention in the left DLPFC and occipital cortex. Higher baseline GABA in the left DLPFC was associated with faster response times (RT) on baseline working memory measures. AtDCS was seen to significantly reduced GABA as compared to sham stimulation in the left DLPFC. There was no effect of atDCS on Glutamate/glutamine (Glx) in the left DLPFC or on GABA/Glx in the occipital cortex. This first such study in adolescents with NF1, showed that atDCS modulates inhibitory activity in the DLPFC. Given the strong evidence linking GABA abnormalities to cognitive deficits across neurodevelopmental conditions such as ASD, modulation of GABA using atDCS offers a promising therapeutic approach.ClinicalTrials.gov Identifier: NCT0499142. Registered 05/08/2021; retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04991428

SMA Selectively Codes the Active Accumulation of Temporal, Not Spatial, Magnitude

2015 ◽  
Vol 27 (11) ◽  
pp. 2281-2298 ◽  
Author(s):  
Jennifer T. Coull ◽  
Pom Charras ◽  
Maxime Donadieu ◽  
Sylvie Droit-Volet ◽  
Franck Vidal
Keyword(s):  
Working Memory ◽  
Visual Cortex ◽  
Stimulus Duration ◽  
Occipital Cortex ◽  
Line Stimulus ◽  
Temporal Domain ◽  
Stimulus Distance ◽  
Spatial Domains ◽  
Dynamic Trajectory ◽  
Active Accumulation

Estimating duration depends on the sequential integration (accumulation) of temporal information in working memory. Using fMRI, we directly compared the accumulation of information in temporal versus spatial domains. Participants estimated either the duration or distance of the dynamic trajectory of a moving dot or, in a control condition, a static line stimulus. Comparing the duration versus distance of static lines activated an extensive cortico-striatal network. By contrast, comparing the duration versus distance of dynamic trajectories, both of which required sequential integration of information, activated SMA alone. Indeed, activity in SMA, as well as right inferior occipital cortex, increased parametrically as a function of stimulus duration and also correlated with individual differences in the propensity to overestimate stimulus duration. By contrast, activity in primary visual cortex increased parametrically as a function of stimulus distance. Crucially, a direct comparison of the parametric responses to duration versus distance revealed that activity in SMA increased incrementally as a function of stimulus duration but not as a function of stimulus distance. Collectively, our results indicate that SMA responds to the active accumulation of information selectively in the temporal domain.

scholarly journals The Role of Location-Context Binding in Nonspatial Visual Working Memory

2018 ◽  
Author(s):  
Ying Cai ◽  
Qing Yu ◽  
Andrew D. Sheldon ◽  
Bradley R. Postle
Keyword(s):  
Working Memory ◽  
Spatial Attention ◽  
Visual Working Memory ◽  
Parietal Cortex ◽  
Memory Load ◽  
Occipital Cortex ◽  
Delay Period ◽  
Fmri Signal ◽  
Associated Representation ◽  
Unique Context

AbstractSuccessful retrieval of an item from visual working memory (VWM) often requires an associated representation of the trial-unique context in which that item was presented. We dissociated the effects on fMRI signal of memory load versus context binding by comparing nonspatial VWM for one oriented bar vs. three bars individuated by their location on the screen vs. three items drawn from different categories (orientation, color, and luminance), for which location context was superfluous. Delay-period fMRI signal in frontal and parietal cortex was sensitive to stimulus homogeneity rather than to memory load per se. Behavioral performance revealed a broad range in swap errors, an index of the efficacy of context binding, and subjects were classified as high swap error or low swap error. During the delay period, the strength of the representation of stimulus location in parietal cortex predicted individual differences in swap errors. During recall, activity in occipital cortex revealed two dissociable neural correlates of context binding: high swap-error subjects allocated less spatial attention to the location of the probed item and more spatial attention the location of non-probed items; high swap-error subjects also represented the orientation of the probed item more weakly and the orientation of nonprobed items more strongly. Our results suggest context binding is a computation that influences all stages of VWM processing.Significance StatementAlthough we often think of the contents of visual working memory (VWM) as representations of the items that need to be remembered, each item’s trial-unique context is also critical for successful performance. For example, if one observes a red, then a black, then a blue car passing through an intersection, vivid memory for the colors, alone, wouldn’t allow one to execute the instruction “Follow the first of the three cars that just drove by.” Although manipulating load is commonly assumed to isolate storage functions, requiring memory for multiple items drawn from the same category also increases demands on the context binding needed to individuate these items. This experiment tracked the influence of context binding on VWM stimulus processing.

Functional MRI in twins discordant for schizophrenia during a working memory task: Preliminary results from the eutwinss study

2011 ◽  
Vol 26 (S2) ◽  
pp. 938-938
Author(s):  
K. Langbein ◽  
M. Dietzek ◽  
G. Mingoia ◽  
R. Maitra ◽  
M. Weisbrod ◽  
...  
Keyword(s):  
Working Memory ◽  
Functional Mri ◽  
Collaborative Study ◽  
Genetic Load ◽  
Memory Task ◽  
Genetic Effect ◽  
Occipital Cortex ◽  
Anterior Cingulate ◽  
Mri Scans ◽  
The Right

IntroductionWorking memory deficits are considered a core feature of disturbed cognition in schizophrenia. Recent neuropsychological studies in twins suggest that there are shared genetic factors between schizophrenia and executive processes.AimWe used a co-twin control design to test the hypothesis that prefrontal activation during a working memory task is seen both in affected as well as unaffected twins discordant for schizophrenia, thus reflecting genetic load on this putative endophenotype.MethodsAs part of EUTwinsS, a multi-centre collaborative study on twins with schizophrenia, we obtained functional MRI scans during a Sternberg working memory task (with one maintenance and one manipulation variations) of twins discordant for schizophrenia (5 monozygotic pairs, 7 dizygotic pairs) and compared them to 10/4 healthy MZ/DZ twins, matched for age and gender.ResultsComparing the overall task-related effects (p < 0.001, uncorrected), we found stronger activation in control twins compared to either Sz-affected or unaffected twins in the right middle frontal gyrus and medial fronto-orbital cortex, and compared to Sz-affected twins also in the left cerebellum and right inferior occipital cortex. Comparing the manipulation vs. maintenance trials, healthy controls showed stronger activation than Sz-affected twins in the left hippocampus, but smaller in right caudate and anterior cingulate, while unaffected co-twins showed diminished right middle and left superior and middle frontal gyri compared to either group.ConclusionsWhile diminished prefrontal activation in unaffected co-twins might indicate compensatory processes during executive control, the overall activation deficits are consistent with a genetic effect on prefrontal cortical efficiency.

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