THE PROCESSING AND ENCODING OF INFORMATION IN THE VISUAL-CORTEX

Our knowledge of the response properties of visual cortical neurons ha s increased steadily since the original studies of Hubel and Wiesel in the 1960s. By comparison, an understanding of the neural mechanisms r esponsible for these properties has proved more elusive. Models for th e mechanisms involved in even the most basic responses, such as the or ientation tuning of simple cells in the primary visual cortex of the c at, remain controversial. Recent studies, however, are providing furth er support for a simple model (first suggested by Hubel and Wiesel), i n which it is hypothesized that the response properties of simple cell s in layer 4 of the cortex are dominated by the convergence of highly specific thalamic inputs.