title: Modular Representation of Luminance Polarity in the Superficial Layers of Primary Visual Cortex.
abstract: The spatial arrangement of luminance increments (ON) and decrements (OFF) falling on the retina provides a wealth of information used by central visual pathways to construct coherent representations of visual scenes. But how the polarity of luminance change is represented in the activity of cortical circuits remains unclear. Using wide-field epifluorescence and two-photon imaging we demonstrate a robust modular representation of luminance polarity (ON or OFF) in the superficial layers of ferret primary visual cortex. Polarity-specific domains are found with both uniform changes in luminance and single light/dark edges, and include neurons selective for orientation and direction of motion. The integration of orientation and polarity preference is evident in the selectivity and discrimination capabilities of most layer 2/3 neurons. We conclude that polarity selectivity is an integral feature of layer 2/3 neurons, ensuring that the distinction between light and dark stimuli is available for further processing in downstream extrastriate areas.
authors.affiliation: Department of Functional Architecture and Development of Cerebral Cortex, Max Planck Florida Institute for Neuroscience, Jupiter, FL 33458, USA.
authors.forename: Gordon B
authors.initials: GB
authors.lastname: Smith
authors.affiliation: Department of Functional Architecture and Development of Cerebral Cortex, Max Planck Florida Institute for Neuroscience, Jupiter, FL 33458, USA.
authors.forename: David E
authors.initials: DE
authors.lastname: Whitney
authors.affiliation: Department of Functional Architecture and Development of Cerebral Cortex, Max Planck Florida Institute for Neuroscience, Jupiter, FL 33458, USA. Electronic address: david.fitzpatrick@mpfi.org.
authors.forename: David
authors.initials: D
authors.lastname: Fitzpatrick
mesh_terms: D000818:Animals; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005289:Ferrets; D005829:Geniculate Bodies; D008856:Microscopy, Fluorescence; D009039:Motion Perception / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D010775:Photic Stimulation; D012160:Retina / Q000502:physiology; D013028:Space Perception / Q000502:physiology; D014793:Visual Cortex / Q000166:cytology / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*