title: Figure-ground modulation in awake primate thalamus.
abstract: Figure-ground discrimination refers to the perception of an object, the figure, against a nondescript background. Neural mechanisms of figure-ground detection have been associated with feedback interactions between higher centers and primary visual cortex and have been held to index the effect of global analysis on local feature encoding. Here, in recordings from visual thalamus of alert primates, we demonstrate a robust enhancement of neuronal firing when the figure, as opposed to the ground, component of a motion-defined figure-ground stimulus is located over the receptive field. In this paradigm, visual stimulation of the receptive field and its near environs is identical across both conditions, suggesting the response enhancement reflects higher integrative mechanisms. It thus appears that cortical activity generating the higher-order percept of the figure is simultaneously reentered into the lowest level that is anatomically possible (the thalamus), so that the signature of the evolving representation of the figure is imprinted on the input driving it in an iterative process.
authors.affiliation: Department of Visual Neuroscience, University College London Institute of Ophthalmology, London EC1V 9EL, United Kingdom; hjones@ioores.co.uk.
authors.forename: Helen E
authors.initials: HE
authors.lastname: Jones
authors.affiliation: Department of Visual Neuroscience, University College London Institute of Ophthalmology, London EC1V 9EL, United Kingdom;
authors.forename: Ian M
authors.initials: IM
authors.lastname: Andolina
authors.affiliation: Department of Visual Neuroscience, University College London Institute of Ophthalmology, London EC1V 9EL, United Kingdom;
authors.forename: Stewart D
authors.initials: SD
authors.lastname: Shipp
authors.affiliation: Beckman Vision Center, University of California, San Francisco, CA 94143; and.
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Adams
authors.affiliation: Department of Medicine, NEUROcom and Institute of Biomedical Research of A Coruña, Campus de Oza, University of A Coruña, s/n 15006, A Coruña, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Cudeiro
authors.affiliation: Department of Visual Neuroscience, University College London Institute of Ophthalmology, London EC1V 9EL, United Kingdom;
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Salt
authors.affiliation: Department of Visual Neuroscience, University College London Institute of Ophthalmology, London EC1V 9EL, United Kingdom;
authors.forename: Adam M
authors.initials: AM
authors.lastname: Sillito
mesh_terms: D000818:Animals; D004192:Discrimination, Psychological / Q000502:physiology*; D005829:Geniculate Bodies / Q000502:physiology; D008253:Macaca mulatta; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation; D013788:Thalamus / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*
keywords: feedback; figure-ground discrimination; lateral geniculate nucleus; perception; vision