Effects of eye closure on the spiking activity of human lateral geniculate neurons.

The lateral geniculate nucleus (LGN) of the thalamus is a key link between the retina and visual cortex but our understanding of the properties of neurons in the human LGN is based on recordings in animal models. Here we recorded spiking activity of cells in the LGN of two patients who had electrodes implanted in the LGN as part of their treatment for epilepsy. Human LGN cells responded to strong visual stimulation with high-frequency bursts of spikes. The cells had receptive-field properties resembling those of monkeys with circular ON-OFF sub-fields, red-green opponency in the dorsal layers and preferences for high temporal frequencies in the ventral layers. Responses were largely monocular and the closure of one eye decreased the spontaneous activity of broad-spiking neurons preferring this eye while increasing the activity of neurons with narrower spikes, suggesting that interneurons might gate LGN activity during eye closure.