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

## TL;DR

This study shows that human LGN neurons behave similarly to those in monkeys and that eye closure affects the activity of specific neurons.

## Contribution

The study provides the first direct recordings of human LGN neurons and reveals how eye closure modulates their activity.

## Key findings

- Human LGN neurons respond to visual stimuli with high-frequency bursts and have receptive-field properties similar to monkeys.
- Eye closure decreases activity in broad-spiking neurons and increases it in narrow-spiking neurons, suggesting inhibitory neuron involvement.
- Responses are largely monocular, with distinct preferences for eye input and temporal frequencies in different LGN layers.

## Abstract

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.

The LGN is a critical stage between the retina and visual cortex, but the properties of human LGN neurons are not fully understood. Here the authors report that they closely resemble those in monkeys and that closure of one eye increases the activity of putative inhibitory neurons connected to that eye.