The hippocampus has been known for decades to be essential for memory, spatial navigation, and emotion. The first cellular layer of processing in the hippocampus occurs at granule cells of the dentate gyrus. How precisely these cells contribution to hippocampal function is poorly understood.
To try and decipher these contributions, the Cembrowski lab took a “cell types” approach to understanding these granule cells, looking to see whether we could identify specific types of granule cells and relate them to function in a publication today in Cell Reports.
Such “cell types” work is roughly akin to a building a neuroscience “periodic table”, says senior author, Dr. Mark Cembrowski, identifying the cellular building blocks of the brain to deconstruct and interpret brain function. “In doing so, we discovered a rare type that strikingly appeared to be selectively active across behavioral paradigms involving memory, spatial navigation, and emotion. This cell type varied from the “textbook” depiction of granule cells, having a variety of atypical features including specialized cell structure, gene expression, and electrical activity.”
In collection, this rare atypical granule cell type appeared to be a “hub” for computation in the dentate gyrus. “We hypothesize that these cells are important for providing a “gestalt” of the external environment; that is, rapidly conveying critical features that are important for survival and well-being,” says Dr. Cembrowski.
“We also hypothesize that more classical textbook granule cells are involved in conveying more subtle information about the environmental, involved in the fine-tuning of cognition and behaviour. In total, our work reveals different cellular layers of processing within a critical brain region, and suggests that these layers facilitate differentially subserve for fast responses and slow adaptation.”
Read Erwin, S., Sun, W., Copeland M., Lindo, S., Spruston N, and Cembrowski, M.S. A Sparse, Spatially Biased Subtype of Mature Granule Cell Dominates Recruitment in Hippocampal-Associated Behaviors. Cell Reports 31:4. 2020 Apr 28. doi: 10.1016/j.celrep.2020.107551. [Epub ahead of print]