scholarly journals Functional Interactions between Prefrontal and Visual Association Cortex Contribute to Top-Down Modulation of Visual Processing

2007 ◽  
Vol 17 (suppl 1) ◽  
pp. i125-i135 ◽  
Author(s):  
A. Gazzaley ◽  
J. Rissman ◽  
J. Cooney ◽  
A. Rutman ◽  
T. Seibert ◽  
...  
Keyword(s):  
Visual Processing ◽  
Association Cortex ◽  
Top Down ◽  
Functional Interactions ◽  
Visual Association Cortex

scholarly journals The Role of Visual Association Cortex in Associative Memory Formation across Development

2018 ◽  
Vol 30 (3) ◽  
pp. 365-380 ◽  
Author(s):  
Maya L. Rosen ◽  
Margaret A. Sheridan ◽  
Kelly A. Sambrook ◽  
Matthew R. Peverill ◽  
Andrew N. Meltzoff ◽  
...  
Keyword(s):  
Associative Memory ◽  
Visual Processing ◽  
Memory Performance ◽  
Neural Mechanism ◽  
Association Cortex ◽  
Associative Memories ◽  
Associate Learning ◽  
Visual Association Cortex ◽  
Age Related

Associative learning underlies the formation of new episodic memories. Associative memory improves across development, and this age-related improvement is supported by the development of the hippocampus and pFC. Recent work, however, additionally suggests a role for visual association cortex in the formation of associative memories. This study investigated the role of category-preferential visual processing regions in associative memory across development using a paired associate learning task in a sample of 56 youths (age 6–19 years). Participants were asked to bind an emotional face with an object while undergoing fMRI scanning. Outside the scanner, participants completed a memory test. We first investigated age-related changes in neural recruitment and found linear age-related increases in activation in lateral occipital cortex and fusiform gyrus, which are involved in visual processing of objects and faces, respectively. Furthermore, greater activation in these visual processing regions was associated with better subsequent memory for pairs over and above the effect of age and of hippocampal and pFC activation on performance. Recruitment of these visual processing regions mediated the association between age and memory performance, over and above the effects of hippocampal activation. Taken together, these findings extend the existing literature to suggest that greater recruitment of category-preferential visual processing regions during encoding of associative memories is a neural mechanism explaining improved memory across development.

Top-down Enhancement and Suppression of the Magnitude and Speed of Neural Activity

2005 ◽  
Vol 17 (3) ◽  
pp. 507-517 ◽  
Author(s):  
Adam Gazzaley ◽  
Jeffrey W. Cooney ◽  
Kevin McEvoy ◽  
Robert T. Knight ◽  
Mark D'Esposito
Keyword(s):  
Neural Activity ◽  
Memory Performance ◽  
Event Related Potential ◽  
Task Instruction ◽  
Association Cortex ◽  
Neural Processing ◽  
Top Down ◽  
Directed Attention ◽  
Performance Deficits ◽  
Visual Association Cortex

Top-down modulation underlies our ability to selectively attend to relevant stimuli and to ignore irrelevant stimuli. Theories addressing neural mechanisms of top-down modulation are driven by studies that reveal increased magnitude of neural activity in response to directed attention, but are limited by a lack of data reporting modulation of neural processing speed, as well as comparisons with a perceptual (passive view) baseline necessary to evaluate the presence of enhancement and suppression. Utilizing functional MRI (fMRI) and event-related potential recordings (ERPs), we provide converging evidence that both themagnitude of neural activity and thespeed of neural processing are modulated by top-down influences. Furthermore, bothenhancement andsuppression occur relative to a perceptual baseline depending on task instruction. These findings reveal the fine degree of influence that goal-directed attention exerts upon activity within the visual association cortex. We further document capacity limitations in top-down enhancement corresponding with working memory performance deficits.

Top-Down Processing and Visual Reorientation Illusions in a Virtual Reality Environment

2004 ◽  
Vol 63 (3) ◽  
pp. 143-149 ◽  
Author(s):  
Fred W. Mast ◽  
Charles M. Oman
Keyword(s):  
Virtual Reality ◽  
Visual Processing ◽  
Line Length ◽  
Perceptual Cues ◽  
Virtual Reality Environment ◽  
Top Down ◽  
Test Conditions ◽  
The Subject ◽  
Processing Mechanisms

The role of top-down processing on the horizontal-vertical line length illusion was examined by means of an ambiguous room with dual visual verticals. In one of the test conditions, the subjects were cued to one of the two verticals and were instructed to cognitively reassign the apparent vertical to the cued orientation. When they have mentally adjusted their perception, two lines in a plus sign configuration appeared and the subjects had to evaluate which line was longer. The results showed that the line length appeared longer when it was aligned with the direction of the vertical currently perceived by the subject. This study provides a demonstration that top-down processing influences lower level visual processing mechanisms. In another test condition, the subjects had all perceptual cues available and the influence was even stronger.

scholarly journals Neuronal Correlates of Multiple Top–Down Signals during Covert Tracking of Moving Objects in Macaque Prefrontal Cortex

2012 ◽  
Vol 24 (10) ◽  
pp. 2043-2056 ◽  
Author(s):  
Ayano Matsushima ◽  
Masaki Tanaka
Keyword(s):  
Prefrontal Cortex ◽  
Object Tracking ◽  
Visual Processing ◽  
Moving Objects ◽  
Top Down ◽  
Selective Suppression ◽  
Internal Object ◽  
Object Segregation ◽  
Task Irrelevant ◽  
The Brain

Resistance to distraction is a key component of executive functions and is strongly linked to the prefrontal cortex. Recent evidence suggests that neural mechanisms exist for selective suppression of task-irrelevant information. However, neuronal signals related to selective suppression have not yet been identified, whereas nonselective surround suppression, which results from attentional enhancement for relevant stimuli, has been well documented. This study examined single neuron activities in the lateral PFC when monkeys covertly tracked one of randomly moving objects. Although many neurons responded to the target, we also found a group of neurons that exhibited a selective response to the distractor that was visually identical to the target. Because most neurons were insensitive to an additional distractor that explicitly differed in color from the target, the brain seemed to monitor the distractor only when necessary to maintain internal object segregation. Our results suggest that the lateral PFC might provide at least two top–down signals during covert object tracking: one for enhancement of visual processing for the target and the other for selective suppression of visual processing for the distractor. These signals might work together to discriminate objects, thereby regulating both the sensitivity and specificity of target choice during covert object tracking.

Functional Architecture of Eye Position Gain Fields in Visual Association Cortex of Behaving Monkey

2003 ◽  
Vol 90 (2) ◽  
pp. 1279-1294 ◽  
Author(s):  
Ralph M. Siegel ◽  
Milena Raffi ◽  
Raymond E. Phinney ◽  
Jessica A. Turner ◽  
Gábor Jandó
Keyword(s):  
Cortical Neurons ◽  
Visual Information ◽  
Parietal Lobe ◽  
Association Cortex ◽  
Eye Position ◽  
Visual Response ◽  
Topographic Map ◽  
Functional Architecture ◽  
Visual Association Cortex ◽  
Area 7A

In the behaving monkey, inferior parietal lobe cortical neurons combine visual information with eye position signals. However, an organized topographic map of these neurons' properties has never been demonstrated. Intrinsic optical imaging revealed a functional architecture for the effect of eye position on the visual response to radial optic flow. The map was distributed across two subdivisions of the inferior parietal lobule, area 7a and the dorsal prelunate area, DP. Area 7a contains a representation of the lower eye position gain fields while area DP represents the upper eye position gain fields. Horizontal eye position is represented orthogonal to the vertical eye position across the medial lateral extents of the cortices. Similar topographies were found in three hemispheres of two monkeys; the horizontal and vertical gain field representations were not isotropic with a greater modulation found with the vertical. Monte Carlo methods demonstrated the significance of the maps, and they were verified in part using multiunit recordings. The novel topographic organization of this association cortex area provides a substrate for constructing representations of surrounding space for perception and the guidance of motor behaviors.

scholarly journals Ocular fixations and presaccadic potentials to explain pareidolias in Parkinson’s disease

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Gajanan S Revankar ◽  
Noriaki Hattori ◽  
Yuta Kajiyama ◽  
Tomohito Nakano ◽  
Masahito Mihara ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Eye Tracking ◽  
Eye Movement ◽  
Visual Processing ◽  
Top Down ◽  
Scalp Eeg ◽  
Wide Range ◽  
Saccade Size ◽  
Global And Local

Abstract In Parkinson’s disease, a precursor phenomenon to visual hallucinations presents as ‘pareidolias’ which make ambiguous forms appear meaningful. To evoke and detect pareidolias in patients, a noise pareidolia test was recently developed, although its task-dependent mechanisms are yet to be revealed. When subjected to this test, we hypothesized that patients exhibiting pareidolias would show altered top-down influence of visual processing allowing us to demonstrate the influence of pareidolic illusionary behaviour in Parkinson’s disease patients. To that end, we evaluated eye-movement strategies and fixation-related presaccadic activity on scalp EEG when participants performed the test. Twelve healthy controls and 21 Parkinson’s disease patients, evaluated for cognitive, visuo-spatial and executive functions, took a modified computer-based version of the noise pareidolia test in a free-viewing EEG eye-tracking experiment. Eye-tracking metrics (fixation-related durations and counts) documented the eye movement behaviour employed in correct responses (face/noise) and misperceptions (pareidolia/missed) during early and late visual search conditions. Simultaneously, EEG recorded the presaccadic activity in frontal and parietal areas of the brain. Based on the noise pareidolia test scores, we found certain Parkinson’s disease patients exhibited pareidolias whereas others did not. ANOVA on eye-tracking data showed that patients dwelled significantly longer to detect faces and pareidolias which affected both global and local search dynamics depending on their visuo-perceptual status. Presaccadic activity in parietal electrodes for the groups was positive for faces and pareidolias, and negative for noise, though these results depended mainly on saccade size. However, patients sensitive to pareidolias showed a significantly higher presaccadic potential on frontal electrodes independent of saccade sizes, suggesting a stronger frontal activation for pareidolic stimuli. We concluded with the following interpretations (i) the noise pareidolia test specifically characterizes visuo-perceptual inadequacies in patients despite their wide range of cognitive scores, (ii) Parkinson’s disease patients dwell longer to converge attention to pareidolic stimuli due to abnormal saccade generation proportional to their visuo-perceptual deficit during early search, and during late search, due to time-independent alteration of visual attentional network and (iii) patients with pareidolias show increased frontal activation reflecting the allocation of attention to irrelevant targets that express the pareidolic phenomenon. While the disease per se alters the visuo-perceptual and oculomotor dynamics, pareidolias occur in Parkinson’s disease due to an abnormal top-down modulation of visual processing that affects visual attention and guidance to ambiguous stimuli.

scholarly journals Top-down influences on visual processing

2013 ◽  
Vol 14 (5) ◽  
pp. 350-363 ◽  
Author(s):  
Charles D. Gilbert ◽  
Wu Li
Keyword(s):  
Visual Processing ◽  
Top Down

scholarly journals Early Top–Down Control of Visual Processing Predicts Working Memory Performance

2010 ◽  
Vol 22 (6) ◽  
pp. 1224-1234 ◽  
Author(s):  
Aaron M. Rutman ◽  
Wesley C. Clapp ◽  
James Z. Chadick ◽  
Adam Gazzaley
Keyword(s):  
Working Memory ◽  
Selective Attention ◽  
Visual Processing ◽  
Temporal Dynamics ◽  
Memory Performance ◽  
Event Related Potential ◽  
Natural Scenes ◽  
Attention And Memory ◽  
Top Down ◽  
Sensory Neural

Selective attention confers a behavioral benefit on both perceptual and working memory (WM) performance, often attributed to top–down modulation of sensory neural processing. However, the direct relationship between early activity modulation in sensory cortices during selective encoding and subsequent WM performance has not been established. To explore the influence of selective attention on WM recognition, we used electroencephalography to study the temporal dynamics of top–down modulation in a selective, delayed-recognition paradigm. Participants were presented with overlapped, “double-exposed” images of faces and natural scenes, and were instructed to either remember the face or the scene while simultaneously ignoring the other stimulus. Here, we present evidence that the degree to which participants modulate the early P100 (97–129 msec) event-related potential during selective stimulus encoding significantly correlates with their subsequent WM recognition. These results contribute to our evolving understanding of the mechanistic overlap between attention and memory.

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