A Sparse, Spatially Biased Subtype of Mature Granule Cell Dominates Recruitment in Hippocampal-Associated Behaviors
This week we profile a recent publication in Cell Reports from Sarah Erwin (pictured, fourth from right)
and the laboratory of Dr. Mark Cembrowski (pictured, centre) at the UBC Life Sciences Institute.
Can you provide a brief overview of your lab’s current research focus?
Our lab works to understand the biological changes involved in forming and retrieving memory in the brain. To do this, we use a combination of experimental and computational techniques to examine the mouse brain at a single-molecule and single-cell resolution. With these techniques, we take a specialized “cell types” approach to understanding the brain – roughly akin to a building a neuroscience “periodic table” – wherein we identify the molecular and cellular building blocks of the brain and use this to understand brain function.
What is the significance of the findings in this publication?
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, we used a cell-types perspectives to see whether we could identify specific types of granule cells and relate them to function. In doing so, we discovered a rare granule cell 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 previously unforeseen “hub” for computation in the dentate gyrus.
What are the next steps for this research?
From this published work, 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. 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 the future, we will perform experiments to image these cells in real time and identify whether these functional signatures can be identified.
This work was funded by:
Funding sources: the NSERC Discovery Grant, CIHR Project Grant, CFI John R. Evans Leaders Fund Grant, and the Howard Hughes Medical Institute.