The nucleus of the optic tract of the opossum.
This paper reviews anatomical and electrophysiological data on the nucleus of the optic tract (NOT) of the opossum, a nucleus in the afferent branch of the horizontal optokinetic reflex. It is proposed that subcortical routes are essential for responses from the two eyes: a direct retinal projection from the contralateral eye and a commissural pathway between the two NOTs for the ipsolateral eye. In the latter case there's evidence that the commisural axons have a relay on inhibitory neurones. This circuit accounts for the differences in response pattern under monocular condition: temporo-nasal motion of the visual stimulus elicits excitation in the contralateral NOT, resulting in inhibition of the ipsolateral nucleus, while naso-temporal motion promotes inhibition in the contralateral nucleus, releasing the ipsolateral nucleus from the commissural input.
Volchan
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E
Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Brasil.
Pereira Júnior
A
A
Vargas
C D
CD
Rocha-Miranda
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CE
D000818:Animals; D017120:Nystagmus, Optokinetic / Q000502:physiology*; D009893:Opossums / Q000502:physiology*