Abstract
Coordination of brain activity, in the form of modulation of feedforward activity by stored information and expectations, occurs across domains of perception and cognition. A reliable and compelling example of this is size contrast in vision. This paper builds on a prior study to show that in healthy humans, the spread of activation in striate and extrastriate visual cortex during a context-modulated size perception task is dependent on the perceived size of the target image, not on the physical size of the retinal image. These data provide further evidence that early regions in visual cortex are modulated by top-down influences, and provide a framework for investigating visual context processing in psychiatric disorders where reduced sensitivity to visual contextual effects has been demonstrated in behavioral tasks.
Highlights
While neuroscience has made significant advances towards understanding the functions and firing properties of individual neurons and brain regions, the topic of their coordinated activity has received far less attention
We have shown that activation of early visual cortex is dependent on the relative perceived size of objects as opposed to their actual size
It has been shown that schizophrenia patients tend to demonstrate more veridical perception when viewing stimuli that normally creates visual illusions and that involves contextual integration, including those where size contrast (Silverstein et al, 2013) and depth perception (Keane, Silverstein, Wang, & Papathomas, 2013) are involved
Summary
While neuroscience has made significant advances towards understanding the functions and firing properties of individual neurons and brain regions, the topic of their coordinated activity has received far less attention. This concept is well established in vision, where the influence of visual stimuli outside of the classical receptive field on primary visual cortex neurons has been convincingly demonstrated (Freeman, Sagi, & Driver, 2001; Zhang & Von der Heydt, 2010; Zhu & Rozell, 2013). Less work has been done on the neural effects of higher cognitive influences on perception, many behavioral studies have demonstrated the effects of emotional state (Damaraju, Huang, Barrett, & Pessoa, 2009; Hu, Padmala, & Pessoa, 2013; Keil et al, 2010), focus of attention (Fang, Boyaci, Kersten, & Murray, 2008; Gilbert, Ito, Kapadia, & Westheimer, 2000), stored information (learning and memory) (Doherty, Campbell, Tsuji, & Phillips, 2010; Doherty, Tsuji, & Phillips, 2008; Li, Piech, & Gilbert, 2008; Papathomas & Bono, 2004), expectations (Silverstein et al, 2006; Silverstein & Keane, 2009; Silverstein et al, 1996; Vetter & Newen, 2014), and social context (Kret & de Gelder, 2010) on visual processing
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
