Visual deprivation modifies glutamate receptor expression in visual and auditory centers.

Changes in the electrical activities of visual and auditory thalamic-cortical regions account for the cross-modal enhancement of auditory perception following visual deprivation, but the molecular regulatory factors mediating these changes remain elusive. In this study, we showed that the expression patterns of five glutamate receptor (GluR) subunits which involved in regulating the synaptic plasticity in mouse primary visual (V1) cortex and primary auditory (A1) cortex undergone elaborate modification with layer-specificity after visual deprivation using dark-exposure (DE). The expression levels of NR1 and NR2B were increased, and those of GluR1 and NR2B in the V1 cortex were decreased after DE. In the A1 cortex, the expression levels of NR1, NR2A and NR2B were increased, and the expression levels of GluR1 and GluR2 were decreased after DE. The altered expression levels of GluR subunits selectively happened in the different layers of V1 and A1 cortices. In addition, the expression level of GluR2 in lateral geniculate nucleus (LGN) was decreased. These results provide novel molecular clues for the plastic neural activity in visual and auditory centers in the absence of visual input, and hint the extensive refinement of intracortical circuits and thalamocortical feedback circuits underlying the multisensory cross-modal plasticity.