Diego B. Piza, Western University
Article citation
Piza, D.B., Corrigan, B.W., Gulli, R.A., Do Carmo, S., Cuello, A.C., Muller, L., Martinez-Trujillo, J. Primacy of vision shapes behavioral strategies and neural substrates of spatial navigation in marmoset hippocampus. Nat Commun 15, 4053 (2024). https://doi.org/10.1038/s41467-024-48374-2
Better understanding the role of vision in the brain’s representation of space by studying freely moving primates
The hippocampus is a structure of the mammalian brain that has been implicated in spatial memory and navigation. Its role has been primarily studied in nocturnal mammals, such as rats, that lack many adaptations for daylight vision. Here, Diego B. Piza, working in the laboratory of Julio Martinez-Trujillo at Western University, demonstrates that during 3D navigation, the common marmoset, a New World primate adapted to daylight, uses different exploration–navigation strategies compared to rats. He further shows that maps of space in the marmoset brain depend on vision-related cues and object relationships used as landmarks for navigation. It is likely that similar encoding mechanisms exist in other diurnal mammals, including humans.
To explore their environment, marmosets predominantly use rapid head-gaze shifts for visual exploration while remaining stationary. During active movement, marmosets stabilize their head, in contrast to rats, who use low-speed head movements to scan the environment as they locomote. This work suggests that spatial memory in primates may rely on anchoring sequences of views to specific places, providing a unique mechanism for encoding spatial experiences.
This publication represents a major technical and conceptual achievement in neuroscience. By studying freely navigating primates in a 3D environment, it overcomes the traditional limitations of static, head-fixed paradigms commonly used in primate and human navigation studies. It challenges the popular understanding of the hippocampus as a “GPS” based on rodent studies, where neurons called place cells encode specific physical locations. By studying freely navigating primates such as marmosets, a primacy of vision emerges, showing that hippocampal neurons integrate multiple variables—including spatial view, head direction, and speed—through mixed selectivity. This suggests that spatial memory in primates may rely on anchoring sequences of views to specific places, rather than on coordinate-like maps, providing a unique mechanism for encoding spatial experiences.
The work also sheds light on the foundational circuitry of hippocampal computations, which has significant implications for understanding memory and navigation. Given the hippocampus’s vulnerability in Alzheimer’s disease, these findings could inform future research into early diagnostic tests (e.g. view-centric spatial cognition tasks) or interventions targeting its functional architecture. This study not only advances our understanding of spatial cognition but also offers a broader framework for investigating how ecological adaptations shape brain function across species.
About Diego B. Piza
Diego Fernando Buitrago Piza performed this work as a Ph.D. student in the laboratory of Julio Martinez-Trujillo at Western University. As the first author, he is a main contributor to all aspects of the work reported in this publication, including experimental conception and design, data collection, data analysis, data visualization, as well as manuscript writing and revision.
Source of funding
This work was supported by the Canadian Institutes of Health Research Project Grant (CIHR); Natural Sciences and Engineering Research Council of Canada (NSERC); Provincial Endowed Academic Chair in Autism; Canada Foundation for Innovation (CFI); Western University BrainsCAN award grant, and Healthy Brains, Healthy Lives (HBHL).