Light deprivation produces distinct morphological orchestrations on RGCs and cortical cells in a depressive-like YFP-H mouse model.

Neural physiological functions and synaptic changes underlying the pathogenesis of depression have obtained great achievements. However, neuronal morphological changes under a depressive state have not been well understood yet. Here a depressive-like YFP-H transgenic mouse model was produced by light deprivation (LD), and morphological changes of retinal ganglion cells (RGCs) and primary visual and auditory cortical layer 5 pyramidal cells (L5PCs) were investigated. Three distinct RGC subtypes were identified based on soma- and dendritic field (DF) size. RGA cells were highlighted by large soma and medium-sized to large DF. RGB cells were characterized by small- to medium-sized soma and small- to medium-sized DF. RGC cells were typical of small- to medium-sized soma and large DF. LD showed cell-type-specific morphological orchestrations on RGCs and predominantly promoted the dendritic growth of RGA cells, leaving no significant effect on RGB and RGC cells. LD produced a consistently suppressed effect on the morphology of primary visual and auditory cortical L5PCs. LD enhanced the dendritic spine density of primary visual cortical L5PCs, implying a compensation mechanism underlying morphological changes in individual cortical L5PCs. The increased morphological complexity of RGA cells and the simplified morphology of cortical L5PCs suggest a broad range of neuronal morphological "cross-modal plasticity" among different brain areas. Our observations in morphological changes of RGCs and cortical L5PCs under a depressive-like state will provide some insights into the pathogenesis of depression at a single neuronal morphological level.