Human hippocampal connectivity is stronger in olfaction than other sensory systems

Guangyu Zhou*, Jonas K. Olofsson, Mohamad Z. Koubeissi, Georgios Menelaou, Joshua Rosenow, Stephan U. Schuele, Pengfei Xu, Joel L. Voss, Gregory Lane, Christina Zelano

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


During mammalian evolution, primate neocortex expanded, shifting hippocampal functional networks away from primary sensory cortices, towards association cortices. Reflecting this rerouting, human resting hippocampal functional networks preferentially include higher association cortices, while those in rodents retained primary sensory cortices. Research on human visual, auditory and somatosensory systems shows evidence of this rerouting. Olfaction, however, is unique among sensory systems in its relative structural conservation throughout mammalian evolution, and it is unknown whether human primary olfactory cortex was subject to the same rerouting. We combined functional neuroimaging and intracranial electrophysiology to directly compare hippocampal functional networks across human sensory systems. We show that human primary olfactory cortex—including the anterior olfactory nucleus, olfactory tubercle and piriform cortex—has stronger functional connectivity with hippocampal networks at rest, compared to other sensory systems. This suggests that unlike other sensory systems, olfactory-hippocampal connectivity may have been retained in mammalian evolution. We further show that olfactory-hippocampal connectivity oscillates with nasal breathing. Our findings suggest olfaction might provide insight into how memory and cognition depend on hippocampal interactions.

Original languageEnglish (US)
Article number102027
JournalProgress in Neurobiology
StatePublished - Jun 2021


  • Functional connectivity
  • Hippocampal network
  • Olfactory system
  • fMRI
  • iEEG

ASJC Scopus subject areas

  • Neuroscience(all)


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