Reactions of lateral geniculate cells to chemical and electrical excitation of the visual cortex in rabbits.

In anesthetized and paralyzed rabbits unitary discharges of lateral geniculate nucleus (LGN) were studied after cortical excitation by strychnine and following electrical stimulation of the visual cortex (VC). Results showed that local application of strychnine produced a general increase of the spontaneous and evoked activity of geniculate cells. By contrast, cortical depression with KCl led to a differential decrement of one of the evoked responses (on or off). Electrical cortical stimulation paired with on or off stimuli led to a differential increment of on or off responses. The results support the notion that, in rabbits, the corticogeniculate system is center-surround organized. A diagrammatic model is proposed to account for the relationship between the VC and the LGN in rabbits.