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Sensitization and centre‐surround antagonism in Necturus retina
Author(s) -
Burkhardt Dwight A.
Publication year - 1974
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1974.sp010454
Subject(s) - sensitization , necturus , retina , chemistry , neuroscience , biophysics , tonic (physiology) , intracellular , biology , biochemistry
1. The impulse discharge of ganglion cells and the proximal negative response were recorded with extracellular micro‐electrodes in Necturus retina and spatial influences of background illumination studied. 2. When a steady background of constant illuminance was extended in diameter from 0·25 to 1 mm, the response to a small concentrically placed test flash was enhanced (sensitization). 3. This sensitization was tonic, showed marked spatial summation, was also found by surrounding a central background with an annulus, and when quantified by threshold measurements, closely resembled the sensitization effect found psychophysically in human vision. 4. Sensitization was prominent in intracellular recordings from bipolar cells and usually apparent in horizontal cells. In bipolar cells, a background change which produced sensitization evoked a large but predominantly transient potential whose polarity was opposite to that evoked by a central flash. 5. The tonicity and large spatial extent of the sensitization effect strongly suggest that it is mediated by horizontal cells. They might do this by either acting upon receptors, bipolar cells, or both.