Cortical neurons related to lens accommodation in posterior lateral suprasylvian area in cats

Abstract

Cortical units were sought that discharged in temporal correlation with spontaneously occurring lens accommodation in the area surrounding the middle suprasylvian sulcus, between the stereotaxic coordinates A8.0 and P1.0, while monitoring lens accommodation by using an infrared optometer. Units were tentatively identified as accommodation related if their discharges were modulated before the onset times of lens accommodation. Forty-eight accommodation-related units were found. Modulation of discharges preceded the onset times of accommodation by 360 ms on the average. Most (95%) of these units were related to the increase in the refractive power of the lens. Antidromic activation from the dorsal midbrain was tested in 26 of 48 accommodation-related units. Fourteen (67%) units were antidromically activated from the superior colliculus and/or the pretectum. Nine (64%) of them were also activated antidromically from the lateral posterior nucleus of the thalamus. The location of these units were confirmed by histological reconstruction. They were found in the posterior medial and posterior lateral lateral suprasylvian (PMLS and PLLS) areas and in the transitional zone of PMLS to the suprasylvian gyrus, between stereotaxic coordinates A7.0 and A1.5.