ISSN:
1432-1106
Keywords:
Optic tract
;
Latencies
;
Centre-excitation
;
Centre-inhibition
;
Cat
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary Excitatory and inhibitory responses of on- and off-centre neurones were elicited by stimuli restricted to the receptive field centres of optic tract units. The latencies of these responses were measured for various stimulus intensities and durations. Latencies depend upon: 1. the total effective luminance, including stimulus and background; 2. the luminance of the test spot relative to threshold luminance: latency changes for a particular light increment near threshold are larger than in the higher supra-threshold range; 3. the latencies of inhibitory responses are further influenced by the activity of the neurone before the onset of inhibition. A comparison of the latencies of excitatory and inhibitory responses showed that, following incremental light stimuli, the off-centre neurones became inhibited before the on-centre neurones were excited. The actual latency difference was a function of stimulus intensity and previous neuronal activity. Following light-off inhibitory responses were again faster, but the difference in time between the inhibition of on-centre neurones and the excitation of off-centre neurones was smaller than for the corresponding on-responses. It is suggested that the earlier onset of inhibitory responses is important for the release of reciprocal inhibition between on- and off-centre neurones in the lateral geniculate body.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00233374
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