scholarly journals Working memory representations in visual cortex mediate distraction effects

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Grace E. Hallenbeck ◽  
Thomas C. Sprague ◽  
Masih Rahmati ◽  
Kartik K. Sreenivasan ◽  
Clayton E. Curtis
Keyword(s):  
Working Memory ◽  
Visual Cortex ◽  
Visual Memory ◽  
Neural Representation ◽  
Association Cortex ◽  
Catastrophic Loss ◽  
Visual Tasks ◽  
Early Visual Cortex ◽  
Memory Representations ◽  
The Impact

AbstractAlthough the contents of working memory can be decoded from visual cortex activity, these representations may play a limited role if they are not robust to distraction. We used model-based fMRI to estimate the impact of distracting visual tasks on working memory representations in several visual field maps in visual and frontoparietal association cortex. Here, we show distraction causes the fidelity of working memory representations to briefly dip when both the memorandum and distractor are jointly encoded by the population activities. Distraction induces small biases in memory errors which can be predicted by biases in neural decoding in early visual cortex, but not other regions. Although distraction briefly disrupts working memory representations, the widespread redundancy with which working memory information is encoded may protect against catastrophic loss. In early visual cortex, the neural representation of information in working memory and behavioral performance are intertwined, solidifying its importance in visual memory.

scholarly journals Working Memory Representations in Visual Cortex Mediate the Effects of Distraction

2021 ◽  
Author(s):  
Grace E. Hallenbeck ◽  
Thomas C. Sprague ◽  
Masih Rahmati ◽  
Kartik K. Sreenivasan ◽  
Clayton E. Curtis
Keyword(s):  
Working Memory ◽  
Visual Cortex ◽  
Neural Representation ◽  
Association Cortex ◽  
Neural Decoding ◽  
Memory Errors ◽  
Catastrophic Loss ◽  
Early Visual Cortex ◽  
Memory Representations ◽  
The Impact

SUMMARYAlthough the contents of working memory (WM) can be decoded from activity in visual cortex, these representations may play a limited role if they are not robust to distraction. Here, we used model-based fMRI to estimate the impact that a distracting visual task had on WM representations in several visual field maps in visual and frontoparietal association cortex. Distraction caused the fidelity of WM representations in all maps to briefly dip when both the memorandum and distractor were jointly encoded by the population activities. Moreover, distraction induced small biases in memory errors which were predicted by biases in neural decoding in early visual cortex, but not other regions. Although distraction briefly disrupts WM representations, the widespread redundancy with which WM information is encoded may protect against catastrophic loss. In early visual cortex, nonetheless, the neural representation of information in WM and behavioral performance were intertwined, solidifying its importance in memory.

scholarly journals The Neural Codes Underlying Internally Generated Representations in Visual Working Memory

2021 ◽  
pp. 1-16
Author(s):  
Qing Yu ◽  
Bradley R. Postle
Keyword(s):  
Working Memory ◽  
Visual Cortex ◽  
Visual Working Memory ◽  
Subjective Experience ◽  
Neural Representation ◽  
Delayed Recall ◽  
Early Visual Cortex ◽  
Memory Representations ◽  
Internal Sources ◽  
Scaling Analyses

Abstract Humans can construct rich subjective experience even when no information is available in the external world. Here, we investigated the neural representation of purely internally generated stimulus-like information during visual working memory. Participants performed delayed recall of oriented gratings embedded in noise with varying contrast during fMRI scanning. Their trialwise behavioral responses provided an estimate of their mental representation of the to-be-reported orientation. We used multivariate inverted encoding models to reconstruct the neural representations of orientation in reference to the response. We found that response orientation could be successfully reconstructed from activity in early visual cortex, even on 0% contrast trials when no orientation information was actually presented, suggesting the existence of a purely internally generated neural code in early visual cortex. In addition, cross-generalization and multidimensional scaling analyses demonstrated that information derived from internal sources was represented differently from typical working memory representations, which receive influences from both external and internal sources. Similar results were also observed in intraparietal sulcus, with slightly different cross-generalization patterns. These results suggest a potential mechanism for how externally driven and internally generated information is maintained in working memory.

scholarly journals Early Visual Cortex Stimulation Modifies Well-Consolidated Perceptual Gains

2020 ◽  
Vol 31 (1) ◽  
pp. 138-146
Author(s):  
Dean Shmuel ◽  
Sebastian M Frank ◽  
Haggai Sharon ◽  
Yuka Sasaki ◽  
Takeo Watanabe ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Perceptual Learning ◽  
Visual Memory ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Low Frequency ◽  
Daily Practice ◽  
Neural Mechanisms ◽  
Resting State Functional Connectivity ◽  
Visual Tasks ◽  
Early Visual Cortex

Abstract Perception thresholds can improve through repeated practice with visual tasks. Can an already acquired and well-consolidated perceptual skill be noninvasively neuromodulated, unfolding the neural mechanisms involved? Here, leveraging the susceptibility of reactivated memories ranging from synaptic to systems levels across learning and memory domains and animal models, we used noninvasive brain stimulation to neuromodulate well-consolidated reactivated visual perceptual learning and reveal the underlying neural mechanisms. Subjects first encoded and consolidated the visual skill memory by performing daily practice sessions with the task. On a separate day, the consolidated visual memory was briefly reactivated, followed by low-frequency, inhibitory 1 Hz repetitive transcranial magnetic stimulation over early visual cortex, which was individually localized using functional magnetic resonance imaging. Poststimulation perceptual thresholds were measured on the final session. The results show modulation of perceptual thresholds following early visual cortex stimulation, relative to control stimulation. Consistently, resting state functional connectivity between trained and untrained parts of early visual cortex prior to training predicted the magnitude of perceptual threshold modulation. Together, these results indicate that even previously consolidated human perceptual memories are susceptible to neuromodulation, involving early visual cortical processing. Moreover, the opportunity to noninvasively neuromodulate reactivated perceptual learning may have important clinical implications.

scholarly journals Different states of priority recruit different neural codes in visual working memory

2018 ◽  
Author(s):  
Qing Yu ◽  
Bradley R. Postle
Keyword(s):  
Working Memory ◽  
Visual Cortex ◽  
Brain Regions ◽  
Focus Of Attention ◽  
Neural Representation ◽  
Stimulus Information ◽  
Brain Areas ◽  
Early Visual Cortex ◽  
A Site ◽  
Different Levels

AbstractWe tracked the neural representation of the orientation and the location of stimuli held in working memory at different levels of priority (“attended” and “unattended” memory items -- AMI and UMI), using multivariate inverted encoding models of human fMRI. Although representation of the orientation of the AMI and of the UMI could be reconstructed in several brain regions, including in early visual and parietal regions, the identity of the UMI was actively represented in early visual cortex in a distinct “reversed” code, suggesting this region as a site of the focus of attention to nonspatial stimulus information. The location of stimuli was also broadly represented, although only in parietal cortex was the location of the UMI represented in a reversed code. Our results suggest that a common recoding operation may be engaged, across stimulus dimensions and brain areas, to retain information in working memory while outside the focus of attention.

scholarly journals Anatomy of early visual cortex predicts visual working memory capacity

2013 ◽  
Vol 13 (9) ◽  
pp. 1349-1349
Author(s):  
J. Bergmann ◽  
E. Genc ◽  
A. Kohler ◽  
W. Singer ◽  
J. Pearson
Keyword(s):  
Working Memory ◽  
Visual Cortex ◽  
Visual Working Memory ◽  
Working Memory Capacity ◽  
Memory Capacity ◽  
Early Visual Cortex

scholarly journals Concurrent feature-specific reactivation within the hippocampus and neocortex facilitates episodic memory retrieval

2021 ◽  
Author(s):  
Michael B. Bone ◽  
Bradley R. Buchsbaum
Keyword(s):  
Visual Cortex ◽  
Memory Retrieval ◽  
Visual Memory ◽  
Recognition Accuracy ◽  
Memory Task ◽  
Large Individual ◽  
Storage And Retrieval ◽  
Specific Index ◽  
Early Visual Cortex ◽  
Episodic Memories

AbstractThe hippocampus is a key brain region for the storage and retrieval of episodic memories, but how it performs this function is unresolved. According to the hippocampal indexing theory, the hippocampus stores an event-specific index of the pattern of neocortical activity that occurred during perception. During retrieval, reactivation of the index by a partial cue facilitates the reactivation of the associated neocortical pattern. Therefore, event-specific retrieval requires joint reactivation of the hippocampal index and the associated neocortical networks. To test this theory, we examine the relation between performance on a recognition memory task requiring retrieval of image-specific visual details and feature-specific reactivation within the hippocampus and neocortex. We show that trial-by-trial recognition accuracy correlates with neural reactivation of low-level features (e.g. luminosity and edges) within the posterior hippocampus and early visual cortex for participants with high recognition lure accuracy. As predicted, the two regions interact, such that recognition accuracy correlates with hippocampal reactivation only when reactivation co-occurs within the early visual cortex (and vice-versa). In addition to supporting the hippocampal indexing theory, our findings show large individual differences in the features underlying visual memory and suggest that the anterior and posterior hippocampus represents gist-like and detailed features, respectively.

scholarly journals The limited contribution of early visual cortex in visual working memory for surface roughness

2020 ◽  
Author(s):  
Munendo Fujimichi ◽  
Hiroki Yamamoto ◽  
Jun Saiki
Keyword(s):  
Working Memory ◽  
Visual Cortex ◽  
Visual Working Memory ◽  
Brain Activity ◽  
Visual Representations ◽  
Brain Regions ◽  
Daily Lives ◽  
Early Visual Cortex ◽  
Roughness Discrimination ◽  
Visual Properties

Are visual representations in the human early visual cortex necessary for visual working memory (VWM)? Previous studies suggest that VWM is underpinned by distributed representations across several brain regions, including the early visual cortex. Notably, in these studies, participants had to memorize images under consistent visual conditions. However, in our daily lives, we must retain the essential visual properties of objects despite changes in illumination or viewpoint. The role of brain regions—particularly the early visual cortices—in these situations remains unclear. The present study investigated whether the early visual cortex was essential for achieving stable VWM. Focusing on VWM for object surface properties, we conducted fMRI experiments while male and female participants performed a delayed roughness discrimination task in which sample and probe spheres were presented under varying illumination. By applying multi-voxel pattern analysis to brain activity in regions of interest, we found that the ventral visual cortex and intraparietal sulcus were involved in roughness VWM under changing illumination conditions. In contrast, VWM was not supported as robustly by the early visual cortex. These findings show that visual representations in the early visual cortex alone are insufficient for the robust roughness VWM representation required during changes in illumination.

scholarly journals Defining the Units of Competition: Influences of Perceptual Organization on Competitive Interactions in Human Visual Cortex

2010 ◽  
Vol 22 (11) ◽  
pp. 2417-2426 ◽  
Author(s):  
Stephanie A. McMains ◽  
Sabine Kastner
Keyword(s):  
Visual Cortex ◽  
Perceptual Organization ◽  
Visual Processing ◽  
Perceptual Grouping ◽  
Neural Representation ◽  
Competitive Interactions ◽  
Illusory Figure ◽  
Processing Stream ◽  
Neural Processes ◽  
Early Visual Cortex

Multiple stimuli that are present simultaneously in the visual field compete for neural representation. At the same time, however, multiple stimuli in cluttered scenes also undergo perceptual organization according to certain rules originally defined by the Gestalt psychologists such as similarity or proximity, thereby segmenting scenes into candidate objects. How can these two seemingly orthogonal neural processes that occur early in the visual processing stream be reconciled? One possibility is that competition occurs among perceptual groups rather than at the level of elements within a group. We probed this idea using fMRI by assessing competitive interactions across visual cortex in displays containing varying degrees of perceptual organization or perceptual grouping (Grp). In strong Grp displays, elements were arranged such that either an illusory figure or a group of collinear elements were present, whereas in weak Grp displays the same elements were arranged randomly. Competitive interactions among stimuli were overcome throughout early visual cortex and V4, when elements were grouped regardless of Grp type. Our findings suggest that context-dependent grouping mechanisms and competitive interactions are linked to provide a bottom–up bias toward candidate objects in cluttered scenes.

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