title: Motion-sensitive responses in visual area V4 in the absence of primary visual cortex.
abstract: Neurons in cortical ventral-stream area V4 are thought to contribute to important aspects of visual processing by integrating information from primary visual cortex (V1). However, how V4 neurons respond to visual stimulation after V1 injury remains unclear: While electrophysiological investigation of V4 neurons during reversible V1 inactivation suggests that virtually all responses are eliminated (Girard et al., 1991), fMRI in humans and monkeys with permanent lesions shows reliable V1-independent activity (Baseler et al., 1999; Goebel et al., 2001; Schmid et al., 2010). To resolve this apparent discrepancy, we longitudinally assessed neuronal functions of macaque area V4 using chronically implanted electrode arrays before and after creating a permanent aspiration lesion in V1. During the month after lesioning, we observed weak yet significant spiking activity in response to stimuli presented to the lesion-affected part of the visual field. These V1-independent responses showed sensitivity for motion and likely reflect the effect of V1-bypassing geniculate input into extrastriate areas.
authors.affiliation: Ernst Strüngmann Institute for Neuroscience in cooperation with Max Planck Society, 60528 Frankfurt, Germany, University of California San Diego, La Jolla, California 92093-0634, Vanderbilt University, Department of Psychology, Nashville, Tennessee 37240, Laboratory of Neuropsychology, National Institute of Mental Health, Bethesda, Maryland 20892, and Neurophysiology Imaging Facility, National Institute of Mental Health, National Institute of Neurological Disorders and Stroke, and National Eye Institute, Bethesda, Maryland 20892.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Schmid
authors.forename: Joscha T
authors.initials: JT
authors.lastname: Schmiedt
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Peters
authors.forename: Richard C
authors.initials: RC
authors.lastname: Saunders
authors.forename: Alexander
authors.initials: A
authors.lastname: Maier
authors.forename: David A
authors.initials: DA
authors.lastname: Leopold
mesh_terms: D000465:Algorithms; D000818:Animals; D001766:Blindness / Q000523:psychology; D003627:Data Interpretation, Statistical; D055724:Electrophysiological Phenomena; D005133:Eye Movements / Q000502:physiology; D005260:Female; D005403:Fixation, Ocular; D008137:Longitudinal Studies; D008253:Macaca mulatta; D008279:Magnetic Resonance Imaging; D009039:Motion Perception / Q000502:physiology*; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000502:physiology; D012607:Scotoma / Q000503:physiopathology; D013028:Space Perception / Q000502:physiology; D014793:Visual Cortex / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology; D014796:Visual Perception / Q000502:physiology