Abstract
The convergence eye movement is known as a disjunctive eye movement in which, typically, both eyes adduct symmetrically in the same time. But asymmetrical convergence also found in the natural condition. These asymmetrical convergence may reflect asymmetries of central control of convergence eye movement. The lateral suprasylvian (LS) areas are extrastriate cortices which receive visual information from V1. The LS has contralateral dominant receptive fields. The cat has convergence-related areas in the LS of both hemispheres. From the short latency regions of convergence-related area, symmetrical convergence was evoked but from convergence eye movements evoked from the long latency regions were asymmetrical. The convergence-related areas have neurons respond to approaching movement of a visual target. Cats (n=7) were trained to start convergence by an alarm signal (buzzer sound or combination of buzz and blinking of LED), preceding target movement by 4s. After training, ocular convergence was elicited by the alarm signal before target movement (predictive open-loop convergence) in 60% of trials. In two cats, we used training with obliquely approaching target. After training, asymmetrical anticipatory eye movements were observed. Based on these findings, related LS neuronal activities and results from lesion study, we will discuss the role of LS in asymmetry of anticipatory and visually-evoked convergence eye movement. [J Physiol Sci. 2006;56 Suppl:S188]
