The lateral spread of light adaptation in cat horizontal cell responses

Vision Res. 1993 Jun;33(9):1173-84. doi: 10.1016/0042-6989(93)90206-c.


To investigate the sites of light adaptation processes in the mammalian distal retina, we studied the lateral spread of adaptation signals in cone-driven cat horizontal (H-) cell responses. The size of the adaptation pool is compared to the receptive field for H-cell responses. H-cell activity was recorded intracellularly in the optically intact, in vivo eye. It is demonstrated that light adaptation as measured in H-cells is not a strictly local process. Background light falling outside a central test region effectively modulates the responses to a small test light, flashed on the receptive field center. The integration area for adaptation signals was quantitatively compared to the H-cell receptive field size by measuring the desensitizing effect of background light on the responses to a small centered test spot, as a function of background spot size. The area-adaptation function is comparable to the area-response function but has a slightly smaller length constant. Light adaptation in H-cell responses, therefore, reveals spread of adaptation over a large distance and is probably mediated through lateral interactions in the H-cell network rather than in the cones.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Ocular / physiology*
  • Animals
  • Cats
  • Light
  • Models, Biological
  • Photic Stimulation
  • Photoreceptor Cells / physiology
  • Retina / cytology
  • Retina / physiology*