Abstract
Convergence eye movements are evoked by approaching visual target and feed-back controlled with its retinal slip. Prediction of target motion improves convergence phase lag in human. In cat, conditionally learned or predicted convergence eye movements are found before the onset of target motion after training with combination of alart signal and target motion. The lateral supurasylvian area (LS) is one of extrastriate visual corteces in cat. Neurons sensitive to a visual target moving in depth are found in LS. Microstimulation in LS elicites convergence eye movement. LS cortical lesions decrease occurance of predicted and amplitude of visually-guided convergence. Amplitude of visually-guided convergence was decreased after injection of muscimol into LS central visual area while predicted convergence was not affected. To investigate the role of LS in these two sort of convergences, we recorded 67 approach neurons in alert cats (n=6). Necessory surgical procedures were done under Nembutal anaesthesia, movement of both eyes were recorded with magnetic coil method, a tungsten-in-glass microelectrode was used for microstimulation and unit recording. Activity of 9 neurons preceeded the predicted convergence and were related to dynamic parametres of convergence. 7 out of 9 neurons were also related to visually-guided convergence. Focusing on these convergence related neurons, we will discuss the role of the LS in controlling visually guided or programmed convergence eye movements. [Jpn J Physiol 54 Suppl:S179 (2004)]
