Temporal properties of the short-wavelength cone mechanism: comparison of receptor and postreceptor signals in the ground squirrel.
Temporal properties of the short-wavelength cone mechanism of the California ground squirrel (Spermophilus beecheyi), a dichromat, were explored with single light pulses and pulse trains. Both the electroretinogram (ERG) and the isolated PIII component of the retinal gross response were recorded under chromatic adaptation conditions that favored the detection of test lights by either the middle-wavelength mechanism or the short-wavelength mechanism. The ERG b-wave generated by the short-wavelength mechanism was significantly slower than that of the middle-wavelength mechanism, but there was no such difference in the PIII components of the two mechanisms. Analysis of PIII revealed that both cone types respond equally well to flicker at rates at least as high as 46 Hz. Differences in the temporal response properties of these two cone mechanisms must arise largely from post-receptoral interactions.
Crognale
M
M
Department of Psychology, University of California, Santa Barbara 93106.
Jacobs
G H
GH
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001224:Aspartic Acid / Q000494:pharmacology; D004596:Electroretinography; D008027:Light; D010786:Photoreceptor Cells / Q000502:physiology*; D012589:Sciuridae / Q000502:physiology*; D013997:Time Factors
D001224:Aspartic Acid