Document Detail

Visual latency and brightness: an interpretation based on the responses of rods and ganglion cells in the frog retina.
MedLine Citation:
PMID:  2487090     Owner:  NLM     Status:  MEDLINE    
Rod and cone photoresponses in a variety of species have been accurately described with linear multistage filter models. In this study, the response latency and initial coding of intensity at two higher levels of visual processing are related to such photoreceptor responses. One level is the retinal output (spiking discharges from frog ganglion cells, based on experimental data reported here), the other is the perceptual level in humans (psychophysical latency and brightness functions, based on data from the literature). Photoreceptor responses are described with the "independent activation" model of Baylor et al. (1974). The intensity dependence of the early ganglion cell discharge, its latency and initial impulse frequency, is shown to follow from such a waveform, assuming that 1) latency L = l + D, where l is the time it takes for the rod response linearly summed over the ganglion cell's receptive field to reach a criterion amplitude, and D is a constant delay; and 2) the initial frequency (below saturation) is proportional to the steepness of rise of the summed rod response at time l. It is shown that the intensity dependences of 1) human visual latency and 2) brightness sensation, including effects of stimulus area and duration, are accounted for by the same model. The predicted functions are not power functions of intensity, but approximate such over wide ranges. Thus, a large body of psychophysical data is explained simply by the waveform of photoreceptor responses.
K Donner
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Visual neuroscience     Volume:  3     ISSN:  0952-5238     ISO Abbreviation:  Vis. Neurosci.     Publication Date:  1989 Jul 
Date Detail:
Created Date:  1991-03-13     Completed Date:  1991-03-13     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  8809466     Medline TA:  Vis Neurosci     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  39-51     Citation Subset:  IM    
Department of Zoology, University of Helsinki, Finland.
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MeSH Terms
Action Potentials
Aspartic Acid / diagnostic use
Models, Neurological
Photic Stimulation
Photoreceptor Cells / physiology*
Rana temporaria
Retinal Ganglion Cells / physiology*
Vision, Ocular / physiology*
Visual Perception / physiology
Reg. No./Substance:
56-84-8/Aspartic Acid

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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