THE SIZE OF THE HORIZONTAL CELL RECEPTIVE-FIELDS ADAPTS TO THE STIMULUS IN THE LIGHT-ADAPTED GOLDFISH RETINA

In this study the dynamic properties of goldfish horizontal cell (HC) receptive fields were evaluated. The size of HC receptive fields incre ases up to about 60 msec after stimulus onset, and then reduces to a s maller end value. They can therefore not adequately be described by th e cable equation. Estimates of the length constant of the HC network b ased on the sustained responses are about 43% smaller than those based on the initial part of the response. This difference can be accounted for by feedback connections from HCs to cones because negative feedba ck reduces the receptive field size. The implication is that HCs are s trongly coupled when the retina is stimulated more or less homogeneous ly but that they partly uncouple from the rest of the HC network when they are stimulated differently than the rest of the retina. The HCs t hus generate a feedback signal based on the ''local'' stimulus propert ies. The size of the HC receptive fields depends on the spatial detail of the stimulus. Copyright (C) 1996 Elsevier Science Ltd.