·To analyze the whole-brain inputs to the projection neurons in the lateral dorsal nucleus (LD) of thalamus innervating primary visual cortex (V1) in mice.

·The adeno-associated virus (AAV) vectors expressing the fusion protein of wheat germ agglutinin and Cre recombinase (Cre) were injected into V1 of C57BL/6J male mice, and the AAV vectors with Cre-inducible expression of avian sarcoma/leukosis virus envelope glycoprotein receptor TVA and rabies glycoprotein were injected into LD, respectively. Twenty-eight days later, the pseudotyped rabies virus (RV) was injected into V1. After the full expression of RV-mediated green fluorescent protein in the infected input neurons of LD, i.e., 7 d later, brain samples were collected and frozen sections were made. The whole-brain distribution of RV-labeled neurons were observed under fluorescence microscope, and quantitative analysis was performed by using high-throughput anatomical data analysis software.

·Through fluorescence microscope and quantitative analysis, the whole-brain map showed that the inputs of LD neurons innervating V1 mainly came from cortex, middle brain and inter brain, accounting for (58.1±4.8)%, (23.2±0.9)% and (15.3±4.0)% of the total number of GFP-labeled neurons in the whole brain, respectively. In the cortex, the areas with the most input neurons were somatomotor area, visual area and somatosensory area. A large number of input neurons were also distributed in prefrontal cortex and medial commissural cortex. In the sensory cortex, the cell bodies of the inputs were mainly distributed in the fifth and sixth layers.

·The direct inputs of LD neuron subgroups innervating V1 in mice are widely distributed throughout the brain, most of which are located in the cortex.