Cortical feedback regulation of input to visual cortex: role of intrageniculate interneurons.

摘要

Non-technical summary Neurons in the dorsal lateral geniculate nucleus (dLGN) process and transmit signals from the retina to the visual cortex. Thalamocortical (TC) neurons and intrinsic interneurons receive input from the retina. TC neurons send output to the visual cortex, while interneurons inhibit TC neurons, forming an inhibitory feed-forward loop. Thus, interneurons are involved in tuning of temporal and spatial resolution of the visual information transmitted through the TC neurons. This processing is regulated by cortical excitatory feedback. To gain insights into the dynamics of cortical regulation, we investigated short-term synaptic plasticity at corticogeniculate synapses on both types of neurons in dLGN. We found depression at cortical synapses on interneurons in contrast to facilitation at cortical synapses on TC neurons. The depression and facilitation had distinctly different temporal characteristics. These differences in synaptic plasticity suggest that cortical feedback to dLGN might either attenuate or enhance thalamocortical transmission in a frequency-dependent manner.