Top-down modulations in the visual form pathway revealed with dynamic causal modeling.

ABSTRACT: Perception entails interactions between activated brain visual areas and the records of previous sensations, allowing for processes like figure-ground segregation and object recognition. The aim of this study was to characterize top-down effects that originate in the visual cortex and that are involved in the generation and perception of form. We performed a functional magnetic resonance imaging experiment, where subjects viewed 3 groups of stimuli comprising oriented lines with different levels of recognizable high-order structure (none, collinearity, and meaning). Our results showed that recognizable stimuli cause larger activations in anterior visual and frontal areas. In contrast, when stimuli are random or unrecognizable, activations are greater in posterior visual areas, following a

SUBMITTER: Cardin V 

PROVIDER: S-EPMC3041008 | biostudies-literature | 2011 Mar

REPOSITORIES: biostudies-literature