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 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.

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 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.

Reduced Cognitive Control Demands after Practice of Saccade Tasks in a Trial Type Probability Manipulation

2017 ◽  
Vol 29 (2) ◽  
pp. 368-381 ◽  
Author(s):  
Jordan E. Pierce ◽  
Jennifer E. McDowell
Keyword(s):  
Cognitive Control ◽  
Parietal Cortex ◽  
Trial Type ◽  
Posterior Parietal Cortex ◽  
Brain Regions ◽  
Mirror Image ◽  
Stimulus Response ◽  
Practice Group ◽  
Task Practice ◽  
Posterior Parietal

Cognitive control is engaged to facilitate stimulus–response mappings for novel, complex tasks and supervise performance in unfamiliar, challenging contexts—processes supported by pFC, ACC, and posterior parietal cortex. With repeated task practice, however, the appropriate task set can be selected in a more automatic fashion with less need for top–down cognitive control and weaker activation in these brain regions. One model system for investigating cognitive control is the ocular motor circuitry underlying saccade production, with basic prosaccade trials (look toward a stimulus) and complex antisaccade trials (look to the mirror image location) representing low and high levels of cognitive control, respectively. Previous studies have shown behavioral improvements on saccade tasks after practice with contradictory results regarding the direction of functional MRI BOLD signal change. The current study presented healthy young adults with prosaccade and antisaccade trials in five mixed blocks with varying probability of each trial type (0%, 25%, 50%, 75%, or 100% anti vs. pro) at baseline and posttest MRI sessions. Between the scans, participants practiced either the specific probability blocks used during testing or only a general 100% antisaccade block. Results indicated an overall reduction in BOLD activation within pFC, ACC, and posterior parietal cortex and across saccade circuitry for antisaccade trials. The specific practice group showed additional regions including ACC, insula, and thalamus with an activation decrease after practice, whereas the general practice group showed a little change from baseline in those clusters. These findings demonstrate that cognitive control regions recruited to support novel task behaviors were engaged less after practice, especially with exposure to mixed task contexts rather than a novel task in isolation.

Reaching-related Neurons in Superior Parietal Area 5: Influence of the Target Visibility

2016 ◽  
Vol 28 (11) ◽  
pp. 1828-1837 ◽  
Author(s):  
Emiliano Brunamonti ◽  
Aldo Genovesio ◽  
Pierpaolo Pani ◽  
Roberto Caminiti ◽  
Stefano Ferraina
Keyword(s):  
Visual Information ◽  
Posterior Parietal Cortex ◽  
Hand Movement ◽  
Visual Signals ◽  
Hand Position ◽  
Movement Initiation ◽  
Starting Position ◽  
Area 5 ◽  
Posterior Parietal ◽  
Target Visibility

Reaching movements require the integration of both somatic and visual information. These signals can have different relevance, depending on whether reaches are performed toward visual or memorized targets. We tested the hypothesis that under such conditions, therefore depending on target visibility, posterior parietal neurons integrate differently somatic and visual signals. Monkeys were trained to execute both types of reaches from different hand resting positions and in total darkness. Neural activity was recorded in Area 5 (PE) and analyzed by focusing on the preparatory epoch, that is, before movement initiation. Many neurons were influenced by the initial hand position, and most of them were further modulated by the target visibility. For the same starting position, we found a prevalence of neurons with activity that differed depending on whether hand movement was performed toward memorized or visual targets. This result suggests that posterior parietal cortex integrates available signals in a flexible way based on contextual demands.

Memory Engrams in the Neocortex

2020 ◽  
pp. 107385842094152
Author(s):  
Svenja Brodt ◽  
Steffen Gais
Keyword(s):  
Posterior Parietal Cortex ◽  
Brain Regions ◽  
Loss Of Function ◽  
Noninvasive Methods ◽  
New Era ◽  
Parallel Memory ◽  
Memory Representations ◽  
Posterior Parietal ◽  
Magnetic Resonance Imaging Mri ◽  
The Brain

While in the past much of our knowledge about memory representations in the brain has relied on loss-of-function studies in which whole brain regions were temporarily inactivated or permanently lesioned, the recent development of new methods has ushered in a new era of downright “engram excitement.” Animal research is now able to specifically label, track, and manipulate engram cells in the brain. While early studies have mostly focused on single brain regions like the hippocampus, recently more and more evidence for brain-wide distributed engram networks is emerging. Memory research in humans has also picked up pace, fueled by promising magnetic resonance imaging (MRI)-based methods like diffusion-weighted MRI (DW-MRI) and brain decoding. In this review, we will outline recent advancements in engram research, with a focus on human data and neocortical representations. We will illustrate the available noninvasive methods for the detection of engrams in different neocortical regions like the medial prefrontal cortex and the posterior parietal cortex and discuss evidence for systems consolidation and parallel memory encoding. Finally, we will explore how reactivation and prior knowledge can lead to and enhance engram formation in the neocortex.

Representation of Eye Position in the Human Parietal Cortex

2010 ◽  
Vol 104 (4) ◽  
pp. 2169-2177 ◽  
Author(s):  
Adrian L. Williams ◽  
Andrew T. Smith
Keyword(s):  
Parietal Cortex ◽  
Cortical Neurons ◽  
Posterior Parietal Cortex ◽  
Visual Stimulation ◽  
Block Design ◽  
Occipital Cortex ◽  
Brain Regions ◽  
Eye Position ◽  
Posterior Aspect ◽  
Posterior Parietal

Neurons that signal eye position are thought to make a vital contribution to distinguishing real world motion from retinal motion caused by eye movements, but relatively little is known about such neurons in the human brain. Here we present data from functional MRI experiments that are consistent with the existence of neurons sensitive to eye position in darkness in the human posterior parietal cortex. We used the enhanced sensitivity of multivoxel pattern analysis (MVPA) techniques, combined with a searchlight paradigm, to isolate brain regions sensitive to direction of gaze. During data acquisition, participants were cued to direct their gaze to the left or right for sustained periods as part of a block-design paradigm. Following the exclusion of saccade-related activity from the data, the multivariate analysis showed sensitivity to tonic eye position in two localized posterior parietal regions, namely the dorsal precuneus and, more weakly, the posterior aspect of the intraparietal sulcus. Sensitivity to eye position was also seen in anterior portions of the occipital cortex. The observed sensitivity of visual cortical neurons to eye position, even in the total absence of visual stimulation, is possibly a result of feedback from posterior parietal regions that receive eye position signals and explicitly encode direction of gaze.

scholarly journals Analysis of haptic information in the cerebral cortex

2016 ◽  
Vol 116 (4) ◽  
pp. 1795-1806 ◽  
Author(s):  
K. Sathian
Keyword(s):  
Cerebral Cortex ◽  
Somatosensory Cortex ◽  
Visual Information ◽  
Occipital Cortex ◽  
Brain Regions ◽  
Primary Somatosensory Cortex ◽  
Intraparietal Sulcus ◽  
Haptic Information ◽  
Lateral Occipital Complex ◽  
Shape Processing

Haptic sensing of objects acquires information about a number of properties. This review summarizes current understanding about how these properties are processed in the cerebral cortex of macaques and humans. Nonnoxious somatosensory inputs, after initial processing in primary somatosensory cortex, are partially segregated into different pathways. A ventrally directed pathway carries information about surface texture into parietal opercular cortex and thence to medial occipital cortex. A dorsally directed pathway transmits information regarding the location of features on objects to the intraparietal sulcus and frontal eye fields. Shape processing occurs mainly in the intraparietal sulcus and lateral occipital complex, while orientation processing is distributed across primary somatosensory cortex, the parietal operculum, the anterior intraparietal sulcus, and a parieto-occipital region. For each of these properties, the respective areas outside primary somatosensory cortex also process corresponding visual information and are thus multisensory. Consistent with the distributed neural processing of haptic object properties, tactile spatial acuity depends on interaction between bottom-up tactile inputs and top-down attentional signals in a distributed neural network. Future work should clarify the roles of the various brain regions and how they interact at the network level.

scholarly journals Neural correlates of visual aesthetic appreciation: insights from non-invasive brain stimulation

2019 ◽  
Vol 238 (1) ◽  
pp. 1-16
Author(s):  
Zaira Cattaneo
Keyword(s):  
Brain Stimulation ◽  
Statistical Power ◽  
Posterior Parietal Cortex ◽  
Brain Regions ◽  
Aesthetic Appreciation ◽  
Lateral Occipital Complex ◽  
Non Invasive ◽  
Extrastriate Body Area ◽  
Dorsolateral Prefrontal ◽  
Cortical Regions

AbstractDuring the last decade, non-invasive brain stimulation techniques have been increasingly employed in the field of neuroaesthetics research to shed light on the possible causal role of different brain regions contributing to aesthetic appreciation. Here, I review studies that have employed transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) to investigate neurocognitive mechanisms mediating visual aesthetic appreciation for different stimuli categories (faces, bodies, paintings). The review first considers studies that have assessed the possible causal contribution of cortical regions in mediating aesthetic appreciation along the visual ventral and dorsal pathways (i.e., the extrastriate body area, the motion-sensitive region V5/MT+ , the lateral occipital complex and the posterior parietal cortex). It then considers TMS and tDCS studies that have targeted premotor and motor regions, as well as other areas involved in body and facial expression processing (such as the superior temporal sulcus and the somatosensory cortex) to assess their role in aesthetic evaluation. Finally, it discusses studies that have targeted medial and dorsolateral prefrontal regions leading to significant changes in aesthetic appreciation for both biological stimuli (faces and bodies) and artworks. Possible mechanisms mediating stimulation effects on aesthetic judgments are discussed. A final section considers both methodological limitations of the reviewed studies (including levels of statistical power and the need for further replication) and the future potential for non-invasive brain stimulation to significantly contribute to the understanding of the neural bases of visual aesthetic experiences.

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