title: Environmental novelty elicits a later theta phase of firing in CA1 but not subiculum.
abstract: The mechanism supporting the role of the hippocampal formation in novelty detection remains controversial. A comparator function has been variously ascribed to CA1 or subiculum, whereas the theta rhythm has been suggested to separate neural firing into encoding and retrieval phases. We investigated theta phase of firing in principal cells in subiculum and CA1 as rats foraged in familiar and novel environments. We found that the preferred theta phase of firing in CA1, but not subiculum, was shifted to a later phase of the theta cycle during environmental novelty. Furthermore, the amount of phase shift elicited by environmental change correlated with the extent of place cell remapping in CA1. Our results support a relationship between theta phase and novelty-induced plasticity in CA1.
authors.affiliation: Behavioural Neuroscience Lab, Institute of Psychological Sciences, University of Leeds, Leeds, United Kingdom. c.lever@leeds.ac.uk
authors.forename: Colin
authors.initials: C
authors.lastname: Lever
authors.forename: Stephen
authors.initials: S
authors.lastname: Burton
authors.forename: Ali
authors.initials: A
authors.lastname: Jeewajee
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Wills
authors.forename: Francesca
authors.initials: F
authors.lastname: Cacucci
authors.forename: Neil
authors.initials: N
authors.lastname: Burgess
authors.forename: John
authors.initials: J
authors.lastname: O'Keefe
mesh_terms: D000200:Action Potentials; D000704:Analysis of Variance; D000818:Animals; D056547:CA1 Region, Hippocampal / Q000502:physiology*; D004569:Electroencephalography; D004777:Environment; D006624:Hippocampus / Q000502:physiology*; D009474:Neurons / Q000502:physiology; D051381:Rats; D013028:Space Perception / Q000502:physiology*; D013826:Theta Rhythm