scholarly journals Dissociated mean and functional connectivity BOLD signals in visual cortex during eyes closed and fixation

2012 ◽  
Vol 108 (9) ◽  
pp. 2363-2372 ◽  
Author(s):  
Mark McAvoy ◽  
Linda Larson-Prior ◽  
Marek Ludwikow ◽  
Dongyang Zhang ◽  
Abraham Z. Snyder ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Functional Connectivity ◽  
Primary Visual Cortex ◽  
Blood Oxygen Level Dependent ◽  
Extrastriate Cortex ◽  
Connected Components ◽  
Bold Signal ◽  
Thalamic Nuclei ◽  
Eyes Closed ◽  
Visual Areas

We investigated the effects of resting state type on blood oxygen level-dependent (BOLD) signal and functional connectivity in two paradigms: participants either alternated between fixation and eyes closed or maintained fixation or eyes closed throughout each scan. The BOLD signal and functional connectivity of lower and higher tiers of the visual cortical hierarchy were found to be differentially modulated during eyes closed versus fixation. Fixation was associated with greater mean BOLD signals in primary visual cortex and lower mean BOLD signals in extrastriate visual areas than periods of eyes closed. In addition, analysis of thalamocortical functional connectivity during scans in which participants maintained fixation showed synchronized BOLD fluctuations between those thalamic nuclei whose mean BOLD signal was systematically modulated during alternating epochs of eyes closed and fixation, primary visual cortex and the attention network, while during eyes closed negatively correlated fluctuations were seen between the same thalamic nuclei and extrastriate visual areas. Finally, in all visual areas the amplitude of spontaneous BOLD fluctuations was greater during eyes closed than during fixation. The dissociation between early and late tiers of visual cortex, which characterizes both mean and functionally connected components of the BOLD signal, may depend on the reorganization of thalamocortical networks. Since dissociated changes in local blood flow also characterize transitions between different stages of sleep and wakefulness (Braun AR, Balkin TJ, Wesenten NJ, Gwadry F, Carson RE, Varga M, Baldwin P, Belenky G, Herscovitch P. Science 279: 91–95, 1998), our results suggest that dissociated endogenous neural activity in primary and extrastriate cortex may represent a general aspect of brain function.

scholarly journals Altered functional connectivity of primary visual cortex in late blindness

2018 ◽  
Vol Volume 14 ◽  
pp. 3317-3327 ◽  
Author(s):  
Zhi Wen ◽  
Fu-Qing Zhou ◽  
Xin Huang ◽  
Han Dong Dan ◽  
Bao-Jun Xie ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Functional Connectivity ◽  
Primary Visual Cortex

scholarly journals Voxel-Wise Linearity Analysis of Increments and Decrements in BOLD Responses in Human Visual Cortex Using a Contrast Adaptation Paradigm

2021 ◽  
Vol 15 ◽  
Author(s):  
Yun Lin ◽  
Xi Zhou ◽  
Yuji Naya ◽  
Justin L. Gardner ◽  
Pei Sun
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Bold Signal ◽  
Transient Responses ◽  
Bold Fmri ◽  
Human Visual Cortex ◽  
Contrast Adaptation ◽  
Bold Responses

The linearity of BOLD responses is a fundamental presumption in most analysis procedures for BOLD fMRI studies. Previous studies have examined the linearity of BOLD signal increments, but less is known about the linearity of BOLD signal decrements. The present study assessed the linearity of both BOLD signal increments and decrements in the human primary visual cortex using a contrast adaptation paradigm. Results showed that both BOLD signal increments and decrements kept linearity to long stimuli (e.g., 3 s, 6 s), yet, deviated from linearity to transient stimuli (e.g., 1 s). Furthermore, a voxel-wise analysis showed that the deviation patterns were different for BOLD signal increments and decrements: while the BOLD signal increments demonstrated a consistent overestimation pattern, the patterns for BOLD signal decrements varied from overestimation to underestimation. Our results suggested that corrections to deviations from linearity of transient responses should consider the different effects of BOLD signal increments and decrements.

scholarly journals Unique spatial integration in mouse primary visual cortex and higher visual areas

2019 ◽  
Author(s):  
Kevin A. Murgas ◽  
Ashley M. Wilson ◽  
Valerie Michael ◽  
Lindsey L. Glickfeld
Keyword(s):  
Visual Cortex ◽  
Visual System ◽  
Primary Visual Cortex ◽  
Spatial Information ◽  
Spatial Scales ◽  
Spatial Integration ◽  
Global Features ◽  
Wide Range ◽  
Visual Areas ◽  
Higher Visual Areas

AbstractNeurons in the visual system integrate over a wide range of spatial scales. This diversity is thought to enable both local and global computations. To understand how spatial information is encoded across the mouse visual system, we use two-photon imaging to measure receptive fields in primary visual cortex (V1) and three downstream higher visual areas (HVAs): LM (lateromedial), AL (anterolateral) and PM (posteromedial). We find significantly larger receptive field sizes and less surround suppression in PM than in V1 or the other HVAs. Unlike other visual features studied in this system, specialization of spatial integration in PM cannot be explained by specific projections from V1 to the HVAs. Instead, our data suggests that distinct connectivity within PM may support the area’s unique ability to encode global features of the visual scene, whereas V1, LM and AL may be more specialized for processing local features.

scholarly journals Beta Oscillation Dynamics in Extrastriate Cortex after Removal of Primary Visual Cortex

2014 ◽  
Vol 34 (35) ◽  
pp. 11857-11864 ◽  
Author(s):  
J. T. Schmiedt ◽  
A. Maier ◽  
P. Fries ◽  
R. C. Saunders ◽  
D. A. Leopold ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Extrastriate Cortex ◽  
Oscillation Dynamics ◽  
Beta Oscillation

scholarly journals Rewarding Feedback After Correct Visual Discriminations Has Both General and Specific Influences on Visual Cortex

2010 ◽  
Vol 104 (3) ◽  
pp. 1746-1757 ◽  
Author(s):  
R. S. Weil ◽  
N. Furl ◽  
C. C. Ruff ◽  
M. Symmonds ◽  
G. Flandin ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Visual Stimuli ◽  
Blood Oxygen Level Dependent ◽  
Blood Oxygen Level ◽  
Neural Basis ◽  
Correct Performance ◽  
Visual Events ◽  
Visual Areas ◽  
Improved Performance ◽  
Time Point

Reward can influence visual performance, but the neural basis of this effect remains poorly understood. Here we used functional magnetic resonance imaging to investigate how rewarding feedback affected activity in distinct areas of human visual cortex, separating rewarding feedback events after correct performance from preceding visual events. Participants discriminated oriented gratings in either hemifield, receiving auditory feedback at trial end that signaled financial reward after correct performance. Greater rewards improved performance for all but the most difficult trials. Rewarding feedback increased blood-oxygen-level-dependent (BOLD) signals in striatum and orbitofrontal cortex. It also increased BOLD signals in visual areas beyond retinotopic cortex, but not in primary visual cortex representing the judged stimuli. These modulations were seen at a time point in which no visual stimuli were presented or expected, demonstrating a novel type of activity change in visual cortex that cannot reflect modulation of response to incoming or anticipated visual stimuli. Rewarded trials led on the next trial to improved performance and enhanced visual activity contralateral to the judged stimulus, for retinotopic representations of the judged visual stimuli in V1. Our findings distinguish general effects in nonretinotopic visual cortex when receiving rewarding feedback after correct performance from consequences of reward for spatially specific responses in V1.

scholarly journals Running reduces firing but improves coding in rodent higher-order visual cortex

2017 ◽  
Author(s):  
Amelia J. Christensen ◽  
Jonathan W. Pillow
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Single Neuron ◽  
Higher Order ◽  
Visual Responses ◽  
Cortical Layers ◽  
Response Properties ◽  
Stimulus Response ◽  
Allen Brain ◽  
Visual Areas

Running profoundly alters stimulus-response properties in mouse primary visual cortex (V1), but its effects in higher-order visual cortex remain unknown. Here we systematically investigated how locomotion modulates visual responses across six visual areas and three cortical layers using a massive dataset from the Allen Brain Institute. Although running has been shown to increase firing in V1, we found that it suppressed firing in higher-order visual areas. Despite this reduction in gain, visual responses during running could be decoded more accurately than visual responses during stationary periods. We show that this effect was not attributable to changes in noise correlations, and propose that it instead arises from increased reliability of single neuron responses during running.

scholarly journals Spatial modulation of visual signals arises in cortex with active navigation

2019 ◽  
Author(s):  
E. Mika Diamanti ◽  
Charu Bai Reddy ◽  
Sylvia Schröder ◽  
Tomaso Muzzu ◽  
Kenneth D. Harris ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Spatial Position ◽  
Visual Signals ◽  
Spatial Modulation ◽  
Visual Responses ◽  
Active Behavior ◽  
Visual Areas ◽  
Familiar Environment ◽  
Higher Visual Areas

During navigation, the visual responses of neurons in primary visual cortex (V1) are modulated by the animal’s spatial position. Here we show that this spatial modulation is similarly present across multiple higher visual areas but largely absent in the main thalamic pathway into V1. Similar to hippocampus, spatial modulation in visual cortex strengthens with experience and requires engagement in active behavior. Active navigation in a familiar environment, therefore, determines spatial modulation of visual signals starting in the cortex.

scholarly journals Widespread correlation patterns of fMRI signal across visual cortex reflect eccentricity organization

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Michael J Arcaro ◽  
Christopher J Honey ◽  
Ryan EB Mruczek ◽  
Sabine Kastner ◽  
Uri Hasson
Keyword(s):  
Visual Cortex ◽  
Visual System ◽  
Visual Space ◽  
Fundamental Question ◽  
Bold Signal ◽  
Topographic Map ◽  
Correlation Pattern ◽  
Visual Areas ◽  
Field Organization ◽  
Receptive Field Organization

The human visual system can be divided into over two-dozen distinct areas, each of which contains a topographic map of the visual field. A fundamental question in vision neuroscience is how the visual system integrates information from the environment across different areas. Using neuroimaging, we investigated the spatial pattern of correlated BOLD signal across eight visual areas on data collected during rest conditions and during naturalistic movie viewing. The correlation pattern between areas reflected the underlying receptive field organization with higher correlations between cortical sites containing overlapping representations of visual space. In addition, the correlation pattern reflected the underlying widespread eccentricity organization of visual cortex, in which the highest correlations were observed for cortical sites with iso-eccentricity representations including regions with non-overlapping representations of visual space. This eccentricity-based correlation pattern appears to be part of an intrinsic functional architecture that supports the integration of information across functionally specialized visual areas.

scholarly journals Increased region of surround stimulation enhances contextual feedback and feedforward processing in human V1

2021 ◽  
Author(s):  
Yulia Revina ◽  
Lucy S Petro ◽  
Cristina B Denk-Florea ◽  
Isa S Rao ◽  
Lars Muckli
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Contextual Information ◽  
Receptive Fields ◽  
Cortical Processing ◽  
Feedback Information ◽  
V1 Neurons ◽  
Visual Areas ◽  
Feedforward Processing ◽  
Higher Visual Areas

The majority of synaptic inputs to the primary visual cortex (V1) are non-feedforward, instead originating from local and anatomical feedback connections. Animal electrophysiology experiments show that feedback signals originating from higher visual areas with larger receptive fields modulate the surround receptive fields of V1 neurons. Theories of cortical processing propose various roles for feedback and feedforward processing, but systematically investigating their independent contributions to cortical processing is challenging because feedback and feedforward processes coexist even in single neurons. Capitalising on the larger receptive fields of higher visual areas compared to primary visual cortex (V1), we used an occlusion paradigm that isolates top-down influences from feedforward processing. We utilised functional magnetic resonance imaging (fMRI) and multi-voxel pattern analysis methods in humans viewing natural scene images. We parametrically measured how the availability of contextual information determines the presence of detectable feedback information in non-stimulated V1, and how feedback information interacts with feedforward processing. We show that increasing the visibility of the contextual surround increases scene-specific feedback information, and that this contextual feedback enhances feedforward information. Our findings are in line with theories that cortical feedback signals transmit internal models of predicted inputs.

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