title: Distinct fMRI Responses to Self-Induced versus Stimulus Motion during Free Viewing in the Macaque.
abstract: Visual motion responses in the brain are shaped by two distinct sources: the physical movement of objects in the environment and motion resulting from one's own actions. The latter source, termed visual reafference, stems from movements of the head and body, and in primates from the frequent saccadic eye movements that mark natural vision. To study the relative contribution of reafferent and stimulus motion during natural vision, we measured fMRI activity in the brains of two macaques as they freely viewed >50 hours of naturalistic video footage depicting dynamic social interactions. We used eye movements obtained during scanning to estimate the level of reafferent retinal motion at each moment in time. We also estimated the net stimulus motion by analyzing the video content during the same time periods. Mapping the responses to these distinct sources of retinal motion, we found a striking dissociation in the distribution of visual responses throughout the brain. Reafferent motion drove fMRI activity in the early retinotopic areas V1, V2, V3, and V4, particularly in their central visual field representations, as well as lateral aspects of the caudal inferotemporal cortex (area TEO). However, stimulus motion dominated fMRI responses in the superior temporal sulcus, including areas MT, MST, and FST as well as more rostral areas. We discuss this pronounced separation of motion processing in the context of natural vision, saccadic suppression, and the brain's utilization of corollary discharge signals.
  
  
  
  Visual motion arises not only from events in the external world, but also from the movements of the observer. For example, even if objects are stationary in the world, the act of walking through a room or shifting one's eyes causes motion on the retina. This "reafferent" motion propagates into the brain as signals that must be interpreted in the context of real object motion. The delineation of whole-brain responses to stimulus versus self-generated retinal motion signals is critical for understanding visual perception and is of pragmatic importance given the increasing use of naturalistic viewing paradigms. The present study uses fMRI to demonstrate that the brain exhibits a fundamentally different pattern of responses to these two sources of retinal motion.
authors.affiliation: Laboratory of Neuropsychology, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, russbe@mail.nih.gov.
authors.forename: Brian E
authors.identifier: 0000-0003-0320-1257
authors.initials: BE
authors.lastname: Russ
authors.affiliation: RIKEN Brain Science Institute, Wako, Saitama 351-0198 Japan, and.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Kaneko
authors.affiliation: Laboratory of Neuropsychology, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: Kadharbatcha S
authors.initials: KS
authors.lastname: Saleem
authors.affiliation: Laboratory of Neuropsychology, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Berman
authors.affiliation: Laboratory of Neuropsychology, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, Neurophysiology Imaging Facility, National Institute of Mental Health, National Institute of Neurological Disorders and Stroke, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: David A
authors.identifier: 0000-0002-1345-6360
authors.initials: DA
authors.lastname: Leopold
mesh_terms: D000818:Animals; D001921:Brain / Q000000981:diagnostic imaging* / Q000502:physiology; D001931:Brain Mapping; D005133:Eye Movements / Q000502:physiology*; D005260:Female; D007091:Image Processing, Computer-Assisted; D008253:Macaca mulatta; D008279:Magnetic Resonance Imaging; D008954:Models, Biological; D009038:Motion; D009039:Motion Perception / Q000502:physiology*; D017711:Nonlinear Dynamics; D010100:Oxygen / Q000097:blood; D010775:Photic Stimulation; D014795:Visual Pathways / Q000000981:diagnostic imaging* / Q000502:physiology
chemical_list: D010100:Oxygen
keywords: MT; V1; free viewing; macaque; reafference; stimulus motion