title: Functional diversity along the transverse axis of hippocampal area CA1.
abstract: Decades of neuroscience research have shed light on the hippocampus as a key structure for the formation of episodic memory. The hippocampus is divided into distinct subfields - CA1, CA2 and CA3. While accumulating evidence points to cellular and synaptic heterogeneity within each subfield, this heterogeneity has not received much attention in computational and behavioural studies and subfields have until recently been considered functionally uniform. However, a couple of recent studies have demonstrated prominent functional differences along the proximodistal axis of the CA1 subfield. Here, we review anatomical and physiological differences that might give rise to heterogeneity along the proximodistal axis of CA1 as well as the functional implications of such heterogeneity. We suggest that such heterogeneity in CA1 operates dynamically in the sense that the CA1 network alternates, on a subsecond scale, between a state where the network is primarily responsive to functionally segregated direct inputs from entorhinal cortex and a state where cells predominantly are controlled by more integrated inputs from CA3.
authors.affiliation: Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Olav Kyrres Gate 9, MTFS, 7491 Trondheim, Norway. Electronic address: kei.igarashi@ntnu.no.
authors.forename: Kei M
authors.initials: KM
authors.lastname: Igarashi
authors.affiliation: Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Olav Kyrres Gate 9, MTFS, 7491 Trondheim, Norway.
authors.forename: Hiroshi T
authors.initials: HT
authors.lastname: Ito
authors.affiliation: Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Olav Kyrres Gate 9, MTFS, 7491 Trondheim, Norway.
authors.forename: Edvard I
authors.initials: EI
authors.lastname: Moser
authors.affiliation: Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Olav Kyrres Gate 9, MTFS, 7491 Trondheim, Norway.
authors.forename: May-Britt
authors.initials: MB
authors.lastname: Moser
mesh_terms: D000818:Animals; D001369:Axons / Q000502:physiology; D056547:CA1 Region, Hippocampal / Q000166:cytology / Q000502:physiology*; D018728:Entorhinal Cortex / Q000166:cytology / Q000502:physiology*; D006801:Humans; D008959:Models, Neurological; D009434:Neural Pathways / Q000502:physiology
keywords: CA1; Direct pathway; Entorhinal cortex; Hippocampus; Transverse axis