Elucidating and Modulating the Neural Correlates of Visuospatial Working Memory via Noninvasive Brain Stimulation

2017 ◽  
Vol 26 (2) ◽  
pp. 165-173 ◽  
Author(s):  
Chi-Hung Juan ◽  
Philip Tseng ◽  
Tzu-Yu Hsu
Keyword(s):  
Working Memory ◽  
Brain Stimulation ◽  
Visual Information ◽  
Posterior Parietal Cortex ◽  
Short Term Memory ◽  
Brain Regions ◽  
Visuospatial Working Memory ◽  
Noninvasive Brain Stimulation ◽  
Memory Mechanism ◽  
Posterior Parietal

Visuospatial working memory refers to the short-term memory mechanism that enables humans to remember visual information across visual blackout periods such as eyeblinks or eye movements. In recent years, neuroscientific studies have made great progress in uncovering the brain regions that support visuospatial working memory. In this review, we focus on the role of the posterior parietal cortex in forming and maintaining visual information, and use it as an example to highlight how noninvasive brain-stimulation techniques, particularly transcranial magnetic, direct current, and alternating current stimulation, can shed light on this topic because of their unique strengths in modulating brain activities.

scholarly journals From visual affordances in monkey parietal cortex to hippocampo–parietal interactions underlying rat navigation

1997 ◽  
Vol 352 (1360) ◽  
pp. 1429-1436 ◽  
Author(s):  
Michael A. Arbib
Keyword(s):  
Parietal Cortex ◽  
Visual Information ◽  
Posterior Parietal Cortex ◽  
Visual Motion ◽  
Graph Model ◽  
Brain Regions ◽  
Formal Similarity ◽  
Posterior Parietal ◽  
Level Model ◽  
Saccade Task

This paper explores the hypothesis that various subregions (but by no means all) of the posterior parietal cortex are specialized to process visual information to extract a variety of affordances for behaviour. Two biologically based models of regions of the posterior parietal cortex of the monkey are introduced. The model of the lateral intraparietal area (LIP) emphasizes its roles in dynamic remapping of the representation of targets during a double saccade task, and in combining stored, updated input with current visual input. The model of the anterior intraparietal area (AIP) addresses parietal–premotor interactions involved in grasping, and analyses the interaction between the AIP and premotor area F5. The model represents the role of other intraparietal areas working in concert with the inferotemporal cortex as well as with corollary discharge from F5 to provide and augment the affordance information in the AIP, and suggests how various constraints may resolve the action opportunities provided by multiple affordances. Finally, a systems–level model of hippocampo–parietal interactions underlying rat navigation is developed, motivated by the monkey data used in developing the above two models as well as by data on neurons in the posterior parietal cortex of the monkey that are sensitive to visual motion. The formal similarity between dynamic remapping (primate saccades) and path integration (rat navigation) is noted, and certain available data on rat posterior parietal cortex in terms of affordances for locomotion are explained. The utility of further modelling, linking the World Graph model of cognitive maps for motivated behaviour with hippocampal–parietal interactions involved in navigation, is also suggested. These models demonstrate that posterior parietal cortex is not only itself a network of interacting subsystems, but functions through cooperative computation with many other brain regions.

Neural Correlates of State- and Strength-based Perception

2014 ◽  
Vol 26 (4) ◽  
pp. 792-809 ◽  
Author(s):  
Mariam Aly ◽  
Charan Ranganath ◽  
Andrew P. Yonelinas
Keyword(s):  
Visual Information ◽  
Posterior Parietal Cortex ◽  
Empirical Work ◽  
Brain Regions ◽  
Posterior Cingulate Cortex ◽  
Lateral Occipital Complex ◽  
Information State ◽  
State Strength ◽  
Strength Based ◽  
Posterior Parietal

Perceptual judgments can be based on two kinds of information: state-based perception of specific, detailed visual information, or strength-based perception of global or relational information. State-based perception is discrete in the sense that it either occurs or fails, whereas strength-based perception is continuously graded from weak to strong. The functional characteristics of these types of perception have been examined in some detail, but whether state- and strength-based perception are supported by different brain regions has been largely unexplored. A consideration of empirical work and recent theoretical proposals suggests that parietal and occipito-temporal regions may be differentially associated with state- and strength-based signals, respectively. We tested this parietal/occipito-temporal state/strength hypothesis using fMRI and a visual perception task that allows separation of state- and strength-based perception. Participants made same/different judgments on pairs of faces and scenes using a 6-point confidence scale where “6” responses indicated a state of perceiving specific details that had changed, and “1” to “5” responses indicated judgments based on varying strength of relational match/mismatch. Regions in the lateral and medial posterior parietal cortex (supramarginal gyrus, posterior cingulate cortex, and precuneus) were sensitive to state-based perception and were not modulated by varying levels of strength-based perception. In contrast, bilateral fusiform gyrus activation was increased for strength-based “different” responses compared with misses and did not show state-based effects. Finally, the lateral occipital complex showed increased activation for state-based responses and additionally showed graded activation across levels of strength-based perception. These results offer support for a state/strength distinction between parietal and temporal regions, with the lateral occipital complex at the intersection of state- and strength-based processing.

scholarly journals An Information-Driven 2-Pathway Characterization of Occipitotemporal and Posterior Parietal Visual Object Representations

2018 ◽  
Vol 29 (5) ◽  
pp. 2034-2050 ◽  
Author(s):  
Maryam Vaziri-Pashkam ◽  
Yaoda Xu
Keyword(s):  
Visual Information ◽  
Neural Coding ◽  
Posterior Parietal Cortex ◽  
Visual Representations ◽  
Brain Regions ◽  
Visual Object ◽  
Object Category ◽  
Representational Space ◽  
Posterior Parietal

Abstract Recent studies have demonstrated the existence of rich visual representations in both occipitotemporal cortex (OTC) and posterior parietal cortex (PPC). Using fMRI decoding and a bottom-up data-driven approach, we showed that although robust object category representations exist in both OTC and PPC, there is an information-driven 2-pathway separation among these regions in the representational space, with occipitotemporal regions arranging hierarchically along 1 pathway and posterior parietal regions along another pathway. We obtained 10 independent replications of this 2-pathway distinction, accounting for 58–81% of the total variance of the region-wise differences in visual representation. The separation of the PPC regions from higher occipitotemporal regions was not driven by a difference in tolerance to changes in low-level visual features, did not rely on the presence of special object categories, and was present whether or not object category was task relevant. Our information-driven 2-pathway structure differs from the well-known ventral-what and dorsal-where/how characterization of posterior brain regions. Here both pathways contain rich nonspatial visual representations. The separation we see likely reflects a difference in neural coding scheme used by PPC to represent visual information compared with that of OTC.

scholarly journals Does perceptual grouping improve visuospatial working memory? Optimized processing or encoding bias

2021 ◽  
Author(s):  
Antonio Prieto ◽  
Vanesa Peinado ◽  
Julia Mayas
Keyword(s):  
Working Memory ◽  
Change Detection ◽  
Visual Working Memory ◽  
Visual Information ◽  
Detection Accuracy ◽  
Visuospatial Working Memory ◽  
Gestalt Grouping ◽  
Color Similarity ◽  
Automatic Encoding ◽  
Change Detection Performance

AbstractVisual working memory has been defined as a system of limited capacity that enables the maintenance and manipulation of visual information. However, some perceptual features like Gestalt grouping could improve visual working memory effectiveness. In two different experiments, we aimed to explore how the presence of elements grouped by color similarity affects the change detection performance of both, grouped and non-grouped items. We combined a change detection task with a retrocue paradigm in which a six item array had to be remembered. An always valid, variable-delay retrocue appeared in some trials during the retention interval, either after 100 ms (iconic-trace period) or 1400 ms (working memory period), signaling the location of the probe. The results indicated that similarity grouping biased the information entered into the visual working memory, improving change detection accuracy only for previously grouped probes, but hindering change detection for non-grouped probes in certain conditions (Exp. 1). However, this bottom-up automatic encoding bias was overridden when participants were explicitly instructed to ignore grouped items as they were irrelevant for the task (Exp. 2).

scholarly journals Temporal Properties of Posterior Parietal Neuron Discharges During Working Memory and Passive Viewing

2007 ◽  
Vol 97 (3) ◽  
pp. 2254-2266 ◽  
Author(s):  
Frederik C. Joelving ◽  
Albert Compte ◽  
Christos Constantinidis
Keyword(s):  
Working Memory ◽  
Posterior Parietal Cortex ◽  
Memory Task ◽  
Power Spectra ◽  
Low Frequency ◽  
Spatial Location ◽  
Spike Trains ◽  
Memory Condition ◽  
Temporal Properties ◽  
Posterior Parietal

Working memory is mediated by the discharges of neurons in a distributed network of brain areas. It was recently suggested that enhanced rhythmicity in neuronal activity may be critical for sustaining remembered information. To test whether working memory is characterized by unique temporal discharge patterns, we analyzed the autocorrelograms and power spectra of spike trains recorded from the posterior parietal cortex of monkeys performing a visuospatial working-memory task. We compared the intervals of active memory maintenance and fixation and repeated the same analysis in spike trains from monkeys never trained to perform any kind of memory task. The most salient effect we observed was a decrease of power in the 5- to 10-Hz frequency range during the presentation of visual stimuli. This pattern was observed both in the working-memory condition and the control condition, although it was more prominent in the former, where it persisted after cue presentation when the monkeys actively remembered the spatial location of the stimulus. Low-frequency power suppression resulted from relative refractory periods that were significantly longer in the working-memory condition and presumably emerged from local-circuit inhibition. We also detected a spectral peak in the 15- to 20-Hz range, although this was more prominent during fixation than during the stimulus and working-memory periods. Our results are in line with previous reports in prefrontal cortex and indicate that unique temporal patterns of single-neuron firing characterize persistent delay activity, although these do not involve the appearance of enhanced oscillations.

Dual-mode Noninvasive Brain Stimulation over Prefrontal Cortices on Working Memory in Stroke Patients

2015 ◽  
Vol 8 (2) ◽  
pp. 359
Author(s):  
Ahee Lee ◽  
Won Hyuk Chang ◽  
Min Ji Lee ◽  
Min-Su Kim ◽  
Yun-Hee Kim
Keyword(s):  
Working Memory ◽  
Brain Stimulation ◽  
Stroke Patients ◽  
Dual Mode ◽  
Noninvasive Brain Stimulation ◽  
Prefrontal Cortices

Neural substrate and underlying mechanisms of working memory: insights from brain stimulation studies

2021 ◽  
Author(s):  
Zakia Z Haque ◽  
Ranshikha Samandra ◽  
Farshad Alizadeh Mansouri
Keyword(s):  
Working Memory ◽  
Brain Stimulation ◽  
Cognitive Functions ◽  
Cognitive Abilities ◽  
Relevant Information ◽  
Brain Regions ◽  
Electrophysiological Recording ◽  
Great Opportunity ◽  
Neural Substrate ◽  
Underlying Mechanisms

The concept of working memory refers to a collection of cognitive abilities and processes involved in the short-term storage of task-relevant information to guide the ongoing and upcoming behaviour and therefore describes an important aspect of executive control of behaviour for achieving goals. Deficits in working memory and related cognitive abilities have been observed in patients with brain damage or neuropsychological disorders and therefore it is important to better understand neural substrate and underlying mechanisms of working memory. Working memory relies on neural mechanisms that enable encoding, maintenance and manipulation of stored information as well as integrating them with ongoing and future goals. Recently, a surge in brain stimulation studies have led to development of various non-invasive techniques for localized stimulation of prefrontal and other cortical regions in humans. These brain stimulation techniques can potentially be tailored to influence neural activities in particular brain regions and modulate cognitive functions and behaviour. Combined use of brain stimulation with neuroimaging and electrophysiological recording have provided a great opportunity to monitor neural activity in various brain regions and non-invasively intervene and modulate cognitive functions in cognitive tasks. These studies have shed more light on the neural substrate and underlying mechanisms of working memory in humans. Here, we review findings and insight from these brain stimulation studies about the contribution of brain regions, and particularly prefrontal cortex, to working memory.

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