title: Functional specialization in rat occipital and temporal visual cortex.
abstract: Recent studies have revealed a surprising degree of functional specialization in rodent visual cortex. Anatomically, suggestions have been made about the existence of hierarchical pathways with similarities to the ventral and dorsal pathways in primates. Here we aimed to characterize some important functional properties in part of the supposed "ventral" pathway in rats. We investigated the functional properties along a progression of five visual areas in awake rats, from primary visual cortex (V1) over lateromedial (LM), latero-intermediate (LI), and laterolateral (LL) areas up to the newly found lateral occipito-temporal cortex (TO). Response latency increased >20 ms from areas V1/LM/LI to areas LL and TO. Orientation and direction selectivity for the used grating patterns increased gradually from V1 to TO. Overall responsiveness and selectivity to shape stimuli decreased from V1 to TO and was increasingly dependent upon shape motion. Neural similarity for shapes could be accounted for by a simple computational model in V1, but not in the other areas. Across areas, we find a gradual change in which stimulus pairs are most discriminable. Finally, tolerance to position changes increased toward TO. These findings provide unique information about possible commonalities and differences between rodents and primates in hierarchical cortical processing.
authors.affiliation: Laboratory of Biological Psychology, KU Leuven, Leuven, Belgium; and.
authors.forename: Ben
authors.initials: B
authors.lastname: Vermaercke
authors.affiliation: Laboratory of Biological Psychology, KU Leuven, Leuven, Belgium; and.
authors.forename: Florian J
authors.initials: FJ
authors.lastname: Gerich
authors.affiliation: Laboratory of Neuroplasticity and Neuroproteomics, KU Leuven, Leuven, Belgium.
authors.forename: Ellen
authors.initials: E
authors.lastname: Ytebrouck
authors.affiliation: Laboratory of Neuroplasticity and Neuroproteomics, KU Leuven, Leuven, Belgium.
authors.forename: Lutgarde
authors.initials: L
authors.lastname: Arckens
authors.affiliation: Laboratory of Biological Psychology, KU Leuven, Leuven, Belgium; and hans.opdebeeck@ppw.kuleuven.be.
authors.forename: Hans P
authors.initials: HP
authors.lastname: Op de Beeck
authors.affiliation: Laboratory of Biological Psychology, KU Leuven, Leuven, Belgium; and.
authors.forename: Gert
authors.initials: G
authors.lastname: Van den Bergh
mesh_terms: D000818:Animals; D009474:Neurons / Q000502:physiology*; D009778:Occipital Lobe / Q000502:physiology*; D010775:Photic Stimulation; D051381:Rats; D014793:Visual Cortex / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*
keywords: high-level vision; population coding; position tolerance; rodent research; single-unit recordings