scholarly journals Higher order image structure enables boundary segmentation in the absence of luminance or contrast cues

2014 ◽  
Vol 14 (4) ◽  
pp. 14-14 ◽  
Author(s):  
E. Zavitz ◽  
C. L. Baker
Keyword(s):  
Higher Order ◽  
Image Structure ◽  
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scholarly journals Laminar differences in responses to naturalistic texture in macaque V1 and V2

2019 ◽  
Author(s):  
Corey M Ziemba ◽  
Richard K Perez ◽  
Julia Pai ◽  
Luke E Hallum ◽  
Christopher Shooner ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Order Statistics ◽  
Higher Order ◽  
Gamma Band ◽  
Single Units ◽  
Higher Order Statistics ◽  
Image Structure ◽  
Gamma Band Activity ◽  
Granular Layers ◽  
Band Activity

AbstractMost single units recorded from macaque V2 respond with higher firing rates to synthetic texture images containing “naturalistic” higher-order statistics than to spectrally matched “noise” images lacking these statistics. In contrast, few single units in V1 show this property. We explored how the strength and dynamics of response vary across the different layers of visual cortex by recording multiunit and gamma band activity evoked by brief presentations of naturalistic and noise images in V1 and V2 of anesthetized macaque monkeys. As previously reported, recordings in V2 showed consistently stronger responses to naturalistic texture than to spectrally matched noise. In contrast to single unit recordings, V1 multiunit activity showed some preference for images with naturalistic statistics, and in gamma band activity this preference was comparable across V1 and V2. Sensitivity to naturalistic image structure was strongest in the supragranular and infragranular layers of V1, but weak in granular layers, suggesting that it might reflect feedback from V2. Response timing was consistent with this idea. Visual responses appeared first in V1, followed by V2. Sensitivity to naturalistic texture emerged first in V2, followed by the supragranular and infragranular layers of V1, and finally in the granular layers of V1. Our results demonstrate laminar differences in the encoding of higher-order statistics of natural texture, and suggest that this sensitivity first arises in V2 and is fed back to modulate activity in V1.Significance StatementThe circuit mechanisms responsible for visual representations of intermediate complexity are largely unknown. We used a well-validated set of synthetic texture stimuli to probe the temporal and laminar profile of sensitivity to the higher-order statistical structure of natural images. We found that this sensitivity emerges first and most strongly in V2 but soon after in V1. However, sensitivity in V1 is higher in the laminae (extragranular) and recording modalities (local field potential) most likely affected by V2 connections, suggesting a feedback origin. Our results show how sensitivity to naturalistic image structure emerges across time and circuitry in the early visual cortex.

scholarly journals A Supervised Learning Approach for Crohn's Disease Detection Using Higher-Order Image Statistics and a Novel Shape Asymmetry Measure

2013 ◽  
Vol 26 (5) ◽  
pp. 920-931 ◽  
Author(s):  
Dwarikanath Mahapatra ◽  
Peter Schueffler ◽  
Jeroen A. W. Tielbeek ◽  
Joachim M. Buhmann ◽  
Franciscus M. Vos
Keyword(s):  
Crohn’S Disease ◽  
Crohn's Disease ◽  
Supervised Learning ◽  
Higher Order ◽  
Disease Detection ◽  
Learning Approach ◽  
Image Statistics ◽  
Asymmetry Measure ◽  
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