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Study reveals new brain ‘corner’ cells that encode environmental geometry

Posted: 2024-03-06

Source: UCI School of Medicine
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Spatial firing rate maps of geometric coding cell types in the subiculum of the brain. The color scale codes the level of neural firing activity (red for high, blue for low). From left to right, concave, convex and straight environmental features are respectively encoded by corner cells (concave or convex) and boundary vector cells.

UC Irvine, Stanford University and UC San Diego team up for breakthrough research in the brain’s spatial mapping system

Irvine, Calif., March. 06, 2024 — A research team co-led by the University of California, Irvine, Stanford University and the University of California, San Diego has discovered that there are special neurons dedicated to representing the convex and concave features of environments (commonly referred to as “corners”) in their study of the brain’s spatial mapping system. 

The study titled “Subicular neurons encode concave and convex geometries” is published today online in the journal Nature. The discovery was made possible by extensive and close collaboration among Drs. Yanjun Sun (Stanford), Douglas A. Nitz (UCSD), Xu Xiangmin (UCI) and Lisa Giocomo (Stanford). Their findings have implications in understanding how our abilities of spatial navigation and environmental explorations are affected in aging and Alzheimer’s disease.

Our brain cells make up the biological equivalent of a GPS system for navigation and exploring the outside world. In addition to the “place” and “grid” cells, which were discovered by 2014 Nobel Prize winners, it has been known that the brain has neurons dedicated to representing environmental boundaries. While the neural substrates underlying the detection of geometric shapes defined by convex and concave features (“corners”) at the junctures between lines have remained elusive, the research team recently discovered that there are special neurons dedicated to representing these convex and concave features of shapes in the brain spatial mapping system. These new findings fill in a significant gap in our understanding of what distinct geometric features are encoded at the single-cell level in the navigation system and further establish that the hippocampal formation region provides the necessary building blocks for representing the complex geometries of naturalistic environments.

“The findings are highly significant. Our work sets the stage for future work aimed at understanding whether such geometric neural representations are adaptive, for example, firing at higher rates for a corner associated with a positive reward such as food or safety versus a neutral association,” said Lisa Giocomo, PhD, professor of neurobiology at Stanford University School of Medicine.   

“Our work also has important implications in the research of Alzheimer’s disease and other learning and memory disorders. We will understand how the ‘corner’ cells are affected in aging and brain disorders including Alzheimer’s disease,” said Xu, PhD, Chancellor’s Professor of anatomy and neurobiology, and director for the Center for Neural Circuit Mapping (CNCM) at the UCI School of Medicine.  

Leveraging the broad collaborative infrastructure and resources of the CNCM, this work was supported by National Institutes of Health grants R01NS104897, RF1AG065675, R01MH126904, R01MH130452, U19NS118284, and K01DA058743.

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