Perceptual Grouping and Object-Based Attention by the Laminar Circuits of Visual Cortex

[Stephen Grossberg]

The following article can be read at
http://www.cns.bu.edu/Profiles/Grossberg/


S. Grossberg and R. D. S. Raizada (1999) Contrast-sensitive perceptual
grouping and object-based attention in the laminar circuits of primary
visual cortex. Vision Research, in press.

ABSTRACT

Recent neurophysiological studies have shown that primary visual cortex, or
V1, does more than passively process image features using the feedforward
filters suggested by Hubel and Wiesel. It also uses horizontal interactions
to group features preattentively into object representations, and feedback
interactions to selectively attend to these groupings. All neocortical
areas, including V1, are organized
into layered circuits. We present a neural model showing how the layered
circuits in areas V1 and V2 enable feedforward, horizontal, and feedback
interactions to complete perceptual groupings over
positions that do not receive contrastive visual inputs, even while
attention can only modulate or prime positions that do not receive such
inputs.  Recent neurophysiological data about how grouping and
attention occur and interact in V1 are simulated and explained, and
testable predictions are made. These simulations show how attention can
selectively propagate along an object grouping and protect it from
competitive masking, and how contextual stimuli can enhance or suppress
groupings in a contrast-sensitive manner.

Preliminary version appears as Boston University Technical Report,
CAS/CNS-TR-99-008.  Available in PDF and gzip'ed postscript.