Visual Input & Gene Expression in Mouse Brain Cells

Article: How vision influences gene expression in mouse brain cells
Source: UCLA Health
Published: January 25, 2022

Graphical abstract

Experiences shape the connections and networks that the brain forms as it develops. Scientists at UCLA and UC Berkeley recently discovered that visual input from the retina in early life also influences the types of cells that develop in the visual cortex, in this case whether the cell is tuned to process information from one eye (monocular) or both eyes (binocular). Surprisingly, the study also revealed for the first time how experience interacts with genes at the cellular level to shape neural development. For example, they found that a vision-dependent gene called Igsf9b, which encodes an inhibitory synaptic cell adhesion molecule, is necessary for the development of binocular cells. Using functional imaging of a mouse model, the researchers saw that monocular cells and binocular cells could gain or lose responsiveness and connectivity based on visual experience. Secondly, using single-cell transcriptomics to see what types of genes were expressed at any one point based on the RNA sequence of the resulting protein, the researchers found that mice deprived of visual experience developed different gene expression profiles than mice exposed to light. Furthermore, the researchers discovered that cell types exist along a gradient, documenting around 250 genes that had varying degrees of expression in different cells. In particular, they sequenced three glutamatergic L2/3 cell types. Since around 70% of those genes affect vision, the absence of visual stimuli affects the gradient of gene expression, and consequently the variety of cells that could develop. That experience could independently influence gene expression and the type of neural cell that develops is a novel finding, contrasting with the prior thought that gene expression was only affected by a cell's location as it migrates to different cortical layers during development. The researchers note that neural cells that form first are intrinsically established before eye-opening, while those that form later and migrate to outermost layers of the cortex were the ones that were dependent on visual experience, adding some evolutionary implications to the finding.

My rating of this study: ⭐⭐⭐🌸

Cheng S, Butrus S, Tan L, et al. "Vision-dependent specification of cell types and function in the developing cortex." Cell.  185(2):P311-327.e24. 20 January 2022. https://doi.org/10.1016/j.cell.2021.12.022