There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.
Abstract
The surround suppression of the receptive field is important for basic visual information
processing, such as orientation specificity. To date, the effects of aging on the
strength of surround suppression are not clear. To address this issue, we carried
out extracellular single-unit studies of the receptive field properties of cells in
the primary visual cortex (area V1) in young and old rhesus (Macaca mulatta) monkeys.
When presented with the oriented central stimulus, we found that cells in old animals
showed reduced orientation and direction selectivity compared with those in young
animals. When presented with the oriented central stimulus together with the optimal
surround stimulus, more selective cells {orientation bias (OB) >/=0.1; a bias of 0.1
is significant at the P<0.005 level} in animals of both ages showed reduced orientation
selectivity compared with the experiment that presented only the oriented central
stimulus. When presented with the optimal central stimulus together with the oriented
surround stimulus, cells in old animals showed reduced orientation and direction selectivity
compared with young animals. Moreover, broadly tuned cells (OB<0.1) in old animals
exhibited significantly reduced suppression indices that quantified the strength of
the surround suppression of the receptive field, when compared with those in young
animals. These results suggest that aging may seriously affect the surround suppression
of the receptive field of V1 cells. Thus, the decreased strength of surround suppression
of the receptive field may be one possible reason for the decreased stimulus selectivity
of V1 cells previously found in the senescent brain. This work will contribute to
an understanding of the physiological mechanisms mediating surround suppression of
the receptive field.
Copyright (c) 2010 IBRO. Published by Elsevier Ltd. All rights reserved.