NEUROBEHAVIORAL MECHANISMS OF HUMAN OLFACTORY NAVIGATION
Degree type
Graduate group
Discipline
Neuroscience and Neurobiology
Subject
fMRI
grid cells
landmarks
odor coding
spatial cognition
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Abstract
Olfaction is arguably the least valued among the sensory systems, and its significance for human behavior is often neglected. Spatial navigation is no exception to the rule: humans are often characterized as purely visual navigators, a view that undermines the contribution of olfactory cues. Accordingly, research investigating whether and how humans use olfaction to navigate space is rare. This dissertation combines virtual reality software, olfactometry methods, and neuroimaging techniques to examine the capacity of the human olfactory system to support spatial navigation. Chapter 2 draws ethological comparisons between human and non-human species to argue that mammalian species – including humans – can exploit odor cues for the purpose of spatial orientation and navigation. The study presented in Chapter 3 shows that human participants can integrate odor landmarks into a coherent cognitive map and are able to use this mental representation to efficiently navigate a virtual space. The data further reveal that this behavior is associated with grid-like responses in entorhinal and piriform cortices, and that neural representations in these two brain areas are attuned to the same grid orientation, suggesting the existence of a specialized olfactory grid network. Chapter 4 directly compares behavioral performance observed for navigation based on olfactory and visual landmarks, with results indicating that both types of sensory cues are equally effective in orienting human participants. Taken together, this dissertation argues that humans can use olfactory landmarks for spatial behaviors thereby challenging the long-held claim that the human olfactory system is intrinsically unfit to aid complex cognitive tasks.