Tiny Neuron Plays Big Role in Navigation

Ellen K .W. Brennan and Omar J. Ahmed

The image above is the second-place winner in the 2026 Brain Initiative Photo & Video Contest and highlights a small but mighty type of neuron. The tiny mouse neuron pictured in white (between the two larger neurons above and below it) plays an outsized role in supporting navigation. 

Located solely in the retrosplenial cortex — a cortical brain region linked to spatial orientation and memory, among other functions — this neuron belongs to a particularly excitable subcategory of brain cells defined by their ability to rapidly fire off communications to other cells, University of Michigan neuroscientist Omar Ahmed told BrainFacts.

The gleaming blue strip running down the image highlights axons from the thalamus, a region tasked with communicating important sensory and motor information to other brain areas. Unlike the two larger neurons, the smaller one's dendrites intersect with this layer. This physical connection gives it the specialized ability to process information related to a mouse’s orientation in the external world. 

Accessing areas the little neuron doesn’t quite reach, the two larger neurons connect with axons stemming from the claustrum — a brain structure located beneath the cortex supporting higher-level functions — pictured in magenta. All other neurons in the tissue sample show up in yellow.

Ahmed, who was lead author of the 2021 study linked to this image, told Michigan News he believes the tiny neuron type evolved to assist with spatial navigation, influencing how quickly and in which direction animals turn their heads. Today, Ahmed and his colleagues are working to understand how these little neurons in mice, and other animals like rats and tree shrews, compare to those in the human retrosplenial cortex.

About the Author

Bella Isaacs-Thomas

Bella is the Staff Writer and Editor for BrainFacts. She previously worked as a digital science reporter at PBS NewsHour, where she was named a fellow in the 2022-2023 class of the National Science-Health-Environment Reporting Fellowships (SHERF) and earned a 2021 D.C. Science Writers Association Newsbrief Award for writing. She graduated from the University of Michigan with a bachelor's degree in 2018.