14C]deoxyglucose uptake of the rat visual centres under monocular optokinetic stimulation

Monocular optokinetic stimulation ( OKS ) in Long-Evans rats enhances the uptake of [14C]2-deoxy-D-glucose (2-DG) in the pretectal nucleus of the optic tract (NOT) and superior colliculus (SC) contralaterally to the open eye regardless of the movement direction. Metabolic increases in NOT and SC are therefore found to be unrelated to the ocular nystagmus that in monocularly viewing rats follows only to OKS nasalward for the seeing eye. Since the oculomotor asymmetry has been attributed to the directional selective properties of NOT neurons responding to nasalward movement in the contralateral visual field but being inhibited by opposite ( temporalward ) movement, the enhanced 2-DG uptakes observed in the present experiments seem to represent the NOT excitatory metabolic work in the case of nasalward movement and the NOT inhibitory metabolic expenditure in the case of temporalward movement.