Directional effect of inactivation of the nucleus of the optic tract on optokinetic nystagmus in the cat.
K.-P. Hoffmann & W.H. Fischer
Vision Research, 41: 3389-3398, 2001
- The goal of the present investigation was to elucidate the role of the
nucleus of the optic tract and the dorsal terminal nucleus of theaccessory optic system (NOT-DTN) for slow eye
movements other than horizontal. Retinal slip neurons in the NOT-DTN in the awake behaving cat respond direction
selectively to the ipsiversive omponent of horizontal and oblique image motion. They are, however, influenced neither
by pure vertical stimulus movement nor by eye movements in the dark. Electrical stimulation of the NOT-DTN leads
to pure horizontal optokinetic nystagmus with ipsiversive slow phases and does not influence vertical eye position.
In addition, unilateral reversible inactivation of the NOT-DTN with
muscimol elicits spontaneous contraversive horizontal nystagmus without vertical component. During oblique optokinetic
stimulation, the ipsiversive OKN component is significantly decreased in all directions. After bilateral NOT-DTN
inactivation, OKN can only be elicited in a narrow range of upward directions. These data indicate that the NOT-DTN
is the only source to drive the horizontal omponent of OKN.
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