Effects of superior colliculus electrolytic lesion on eye movements evoked through electrical stimulation of the pulvinar-lateralis posterior complex

In 27 encéphale isolé cats, electrical stimulation of the pulvinar-lateralis posterior nucleus complex (P-LP) evoked oblique conjugate saccadic eye movements, with latencies of 60 to 90 ms and stimulus thresholds of 200 to 300 μA. Unilateral superior colliculus electrolytic lesion suppressed the eye movements induced by electrical stimulation of the ipsilateral P-LP, even with stimuli three to four times higher than threshold. The contralateral P-LP maintained its capacity to induce eye movement. A motor deficit was observed in the eye ipsilateral to the damaged superior colliculus. Electrical stimulation with 1 to 2 mA of the cerebral cortex receiving afferent projections from the P-LP induced horizontal eye movements with latencies of 130 to 150 ms. These results confirm the P-LP participation in oculomotility and we postulate that the ocular P-LP signal output travels through the ipsilateral superior colliculus. © 1982