title: Feedback enhances feedforward figure-ground segmentation by changing firing mode.
abstract: In the visual cortex, feedback projections are conjectured to be crucial in figure-ground segregation. However, the precise function of feedback herein is unclear. Here we tested a hypothetical model of reentrant feedback. We used a previous developed 2-layered feedforward spiking network that is able to segregate figure from ground and included feedback connections. Our computer model data show that without feedback, neurons respond with regular low-frequency (∼9 Hz) bursting to a figure-ground stimulus. After including feedback the firing pattern changed into a regular (tonic) spiking pattern. In this state, we found an extra enhancement of figure responses and a further suppression of background responses resulting in a stronger figure-ground signal. Such push-pull effect was confirmed by comparing the figure-ground responses with the responses to a homogenous texture. We propose that feedback controls figure-ground segregation by influencing the neural firing patterns of feedforward projecting neurons.
authors: Institute for Brain, Cognition and Behavior (IR3C), Barcelona, Spain. hans.super@icrea.es
authors: Hans
authors: H
authors: Supèr
authors: August
authors: A
authors: Romeo
mesh_terms: D000818:Animals; D003198:Computer Simulation; D006801:Humans; D009474:Neurons / Q000502:physiology; D014793:Visual Cortex / Q000502:physiology*