Relationship between functional characteristics of cat visual cortex neurons, their response to novelty, and short-term memory

1971 ◽  
Vol 2 (6) ◽  
pp. 462-467
Author(s):  
V. G. Samsonova
Keyword(s):  
Visual Cortex ◽  
Short Term Memory ◽  
Short Term ◽  
Functional Characteristics ◽  
Term Memory ◽  
Cat Visual Cortex ◽  
Visual Cortex Neurons

scholarly journals Short-Term Memory for Figure-Ground Organization in the Visual Cortex

Neuron ◽  
2009 ◽  
Vol 61 (5) ◽  
pp. 801-809 ◽  
Author(s):  
Philip O'Herron ◽  
Rüdiger von der Heydt
Keyword(s):  
Visual Cortex ◽  
Short Term Memory ◽  
Short Term ◽  
Term Memory ◽  
Ground Organization

scholarly journals Sensory Recruitment in Visual Short-Term Memory: A Systematic Review and Meta-Analysis of Sensory Visual Cortex Interference Using Transcranial Magnetic Stimulation

2021 ◽  
Author(s):  
Phivos Phylactou ◽  
Artemis Traikapi ◽  
Marietta Papadatou-Pastou ◽  
Nikos Konstantinou
Keyword(s):  
Visual Cortex ◽  
Visual Information ◽  
Short Term Memory ◽  
Meta Analysis ◽  
Maintenance Phase ◽  
Brain Network ◽  
Effect Sizes ◽  
Short Term ◽  
Term Memory ◽  
Meta Analyses

Visual short-term memory (VSTM) links perception with higher cognitive processes by maintaining visual information that is absent from the environment. Yet, it remains unclear if sensory visual cortex is a necessary component of the brain network that underlies short-term maintenance of visual information. Previous reviews remain inconclusive and open to interpretation. Here, we aimed to systematically identify and review studies that have investigated the role of the sensory visual cortex in VSTM using transcranial magnetic stimulation (TMS), a method that allows exploration of causal relationships, and to quantitatively explore the effect of TMS interference on the sensory visual cortex during VSTM using meta-analytic methodology. Thirteen studies were identified and qualitatively reviewed. Out of those, seven studies provided sufficient statistical data for meta-analysis and yielded a total of 30 effect sizes, which were included in the meta-analyses. Two meta-analyses were conducted, one regarding the encoding phase of VSTM (19 effect sizes), and one regarding the maintenance phase of VSTM (11 effect sizes). The results from the systematic review and the two meta-analyses indicate that the sensory visual cortex is likely involved in both the encoding and maintenance phase of VSTM. In some cases, evidence did not show significant effects of TMS, however, this is suggested to be due to low memory load or low perceptual task demands. Overall, these findings support the idea that sensory visual areas are part of the brain network responsible for successfully maintaining information in short-term memory when no physical stimulus is present in the environment.

Top–Down Modulation from Inferior Frontal Junction to FEFs and Intraparietal Sulcus during Short-term Memory for Visual Features

2013 ◽  
Vol 25 (11) ◽  
pp. 1944-1956 ◽  
Author(s):  
Markus H. Sneve ◽  
Svein Magnussen ◽  
Dag Alnæs ◽  
Tor Endestad ◽  
Mark D'Esposito
Keyword(s):  
Visual Cortex ◽  
Memory Retrieval ◽  
Short Term Memory ◽  
Orientation Discrimination ◽  
Intraparietal Sulcus ◽  
Memory Encoding ◽  
Top Down ◽  
Short Term ◽  
Term Memory ◽  
Inferior Frontal Junction

Visual STM of simple features is achieved through interactions between retinotopic visual cortex and a set of frontal and parietal regions. In the present fMRI study, we investigated effective connectivity between central nodes in this network during the different task epochs of a modified delayed orientation discrimination task. Our univariate analyses demonstrate that the inferior frontal junction (IFJ) is preferentially involved in memory encoding, whereas activity in the putative FEFs and anterior intraparietal sulcus (aIPS) remains elevated throughout periods of memory maintenance. We have earlier reported, using the same task, that areas in visual cortex sustain information about task-relevant stimulus properties during delay intervals [Sneve, M. H., Alnæs, D., Endestad, T., Greenlee, M. W., & Magnussen, S. Visual short-term memory: Activity supporting encoding and maintenance in retinotopic visual cortex. Neuroimage, 63, 166–178, 2012]. To elucidate the temporal dynamics of the IFJ-FEF-aIPS-visual cortex network during memory operations, we estimated Granger causality effects between these regions with fMRI data representing memory encoding/maintenance as well as during memory retrieval. We also investigated a set of control conditions involving active processing of stimuli not associated with a memory task and passive viewing. In line with the developing understanding of IFJ as a region critical for control processes with a possible initiating role in visual STM operations, we observed influence from IFJ to FEF and aIPS during memory encoding. Furthermore, FEF predicted activity in a set of higher-order visual areas during memory retrieval, a finding consistent with its suggested role in top–down biasing of sensory cortex.

Visual short-term memory: Activity supporting encoding and maintenance in retinotopic visual cortex

NeuroImage ◽  
2012 ◽  
Vol 63 (1) ◽  
pp. 166-178 ◽  
Author(s):  
Markus H. Sneve ◽  
Dag Alnæs ◽  
Tor Endestad ◽  
Mark W. Greenlee ◽  
Svein Magnussen
Keyword(s):  
Visual Cortex ◽  
Short Term Memory ◽  
Short Term ◽  
Term Memory ◽  
Visual Short Term Memory

Direction of Report in Spatial and Verbal Serial Short term Memory

1996 ◽  
Vol 49 (1) ◽  
pp. 140-158 ◽  
Author(s):  
Paul Farrand ◽  
Dylan Jones
Keyword(s):  
Serial Recall ◽  
Short Term Memory ◽  
Forward Direction ◽  
Order Information ◽  
Short Term ◽  
Functional Characteristics ◽  
Term Memory ◽  
Verbal Tasks

Four experiments examined the role played by item and order information in determining the effects of order of report of a sequence from short-term memory. Experiments in which list items were re-presented prior to recall so that only their order had to be reported showed no differences in performance between the forward and backward direction of report. This result was found with lists of auditory-verbal, visual-verbal, and spatial stimuli. When the list items were not re-presented, so that recall of both items and order was required, recall in the backward direction of report was significantly worse than in the forward direction of report, both in spatial and verbal tasks. The results point to the symmetry of inter-item associations, though only equivocally so, but they suggest strongly that the processes of spatial and verbal serial recall share many functional characteristics.

scholarly journals Visual working memory is independent of the cortical spacing between memoranda

2017 ◽  
Author(s):  
William J. Harrison ◽  
Paul M. Bays
Keyword(s):  
Working Memory ◽  
Visual Cortex ◽  
Short Term Memory ◽  
Visual Features ◽  
Short Term ◽  
Term Memory ◽  
Neural Architecture ◽  
Memory Representations ◽  
Stimulus Features ◽  
Cortical Representations

AbstractThe sensory recruitment hypothesis states that visual short term memory is maintained in the same visual cortical areas that initially encode a stimulus’ features. Although it is well established that the distance between features in visual cortex determines their visibility, a limitation known as crowding, it is unknown whether short term memory is similarly constrained by the cortical spacing of memory items. Here we investigated whether the cortical spacing between sequentially presented memoranda affects the fidelity of memory in humans (of both sexes). In a first experiment, we varied cortical spacing by taking advantage of the log-scaling of visual cortex with eccentricity, sequentially presenting memoranda in peripheral vision along either the radial or tangential visual axis with respect to the fovea. In a second experiment, we sequentially presented memoranda either within or beyond the critical spacing of visual crowding, a distance within which visual features cannot be perceptually distinguished due to their nearby cortical representations. In both experiments and across multiple measures, we found strong evidence that the ability to maintain visual features in memory is unaffected by cortical spacing. These results indicate that the neural architecture underpinning working memory has properties inconsistent with the known behaviour of sensory neurons in visual cortex. Instead, the dissociation between perceptual and memory representations supports a role of higher cortical areas, such as posterior parietal or prefrontal regions, or may involve an as yet unspecified mechanism in visual cortex in which stimulus features are bound to their temporal order.Significance StatementAlthough much is known about the resolution with which we can remember visual objects, the cortical representation of items held in short term memory remains contentious. A popular hypothesis suggests that memory of visual features is maintained via the recruitment of the same neural architecture in sensory cortex that encodes stimuli. We investigated this claim by manipulating the spacing in visual cortex between sequentially presented memoranda such that some items shared cortical representations more than others, while preventing perceptual interference between stimuli. We found clear evidence that short term memory is independent of the intra-cortical spacing of memoranda, revealing a dissociation between perceptual and memory representations. Our data indicate that working memory relies on different neural mechanisms from sensory perception.

scholarly journals Causal evidence for the role of the sensory visual cortex in visual short-term memory maintenance

2021 ◽  
Author(s):  
Phivos Phylactou ◽  
Andria Shimi ◽  
Nikos Konstantinou
Keyword(s):  
Visual Cortex ◽  
Right Hemisphere ◽  
Short Term Memory ◽  
Methodological Issues ◽  
Short Term ◽  
Term Memory ◽  
Visual Short Term Memory ◽  
Behavioural Effects ◽  
Visual Hemifield

The role of the sensory visual cortex during visual short-term memory (VSTM) remains controversial. This controversy is possibly due to methodological issues in previous attempts to investigate the effects of transcranial magnetic stimulation (TMS) on VSTM. This study aims to use TMS, while covering previous methodological deficits. Young adults will be recruited to participate in two experiments using a VSTM orientation change-detection under TMS. Monocular vision will be ensured using red-blue goggles combined with red-blue stimuli. Double-pulse TMS will be delivered at different times (Experiment 1: 0ms, 200ms, or 1000ms; Experiment 2: 200ms, 1000ms) during a 2 s retention phase, on one side of the occipital hemisphere (right hemisphere for 50% of the participants). In experiment 2, a sham-TMS condition will be introduced. Behavioural effects in the ipsilateral occipital hemisphere to visual hemifield will indicate a causal involvement of the sensory visual cortex during a specific temporal point in VSTM.

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