title: Relational associative learning induces cross-modal plasticity in early visual cortex.
abstract: Neurobiological theories of memory posit that the neocortex is a storage site of declarative memories, a hallmark of which is the association of two arbitrary neutral stimuli. Early sensory cortices, once assumed uninvolved in memory storage, recently have been implicated in associations between neutral stimuli and reward or punishment. We asked whether links between neutral stimuli also could be formed in early visual or auditory cortices. Rats were presented with a tone paired with a light using a sensory preconditioning paradigm that enabled later evaluation of successful association. Subjects that acquired this association developed enhanced sound evoked potentials in their primary and secondary visual cortices. Laminar recordings localized this potential to cortical Layers 5 and 6. A similar pattern of activation was elicited by microstimulation of primary auditory cortex in the same subjects, consistent with a cortico-cortical substrate of association. Thus, early sensory cortex has the capability to form neutral stimulus associations. This plasticity may constitute a declarative memory trace between sensory cortices.
authors.affiliation: Center for the Neurobiology of Learning and Memory, Department of Neurobiology and Behavior, University of California, Irvine, CA 92697-3800, USA.
authors.forename: Drew B
authors.initials: DB
authors.lastname: Headley
authors.affiliation: Center for the Neurobiology of Learning and Memory, Department of Neurobiology and Behavior, University of California, Irvine, CA 92697-3800, USA.
authors.forename: Norman M
authors.initials: NM
authors.lastname: Weinberger
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D000818:Animals; D001245:Association Learning / Q000502:physiology*; D001303:Auditory Cortex / Q000502:physiology*; D001307:Auditory Perception / Q000502:physiology; D003214:Conditioning, Classical / Q000502:physiology; D005071:Evoked Potentials / Q000502:physiology; D008027:Light; D008297:Male; D009473:Neuronal Plasticity / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014793:Visual Cortex / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology
keywords: auditory cortex; cross-modal; plasticity; sensory preconditioning; visual cortex