title: Neural substrates underlying the passive observation and active control of translational egomotion.
abstract: Moving or static obstacles often get in the way while walking in daily life. Avoiding obstacles involves both perceptual processing of motion information and controlling appropriate defensive movements. Several higher-level motion areas, including the ventral intraparietal area (VIP), medial superior temporal area, parieto-insular vestibular cortex (PIVC), areas V6 and V6A, and cingulate sulcus visual area, have been identified in humans by passive viewing of optic flow patterns that simulate egomotion and object motion. However, the roles of these areas in the active control of egomotion in the real world remain unclear. Here, we used functional magnetic resonance imaging (fMRI) to map the neural substrates underlying the passive observation and active control of translational egomotion in humans. A wide-field virtual reality environment simulated a daily scenario where doors randomly swing outward while walking in a hallway. The stimuli of door-dodging events were essentially the same in two event-related fMRI experiments, which compared passive and active dodges in response to swinging doors. Passive dodges were controlled by a computer program, while active dodges were controlled by the subject. Passive dodges activated several higher-level areas distributed across three dorsal motion streams in the temporal, parietal, and cingulate cortex. Active dodges most strongly activated the temporal-vestibular stream, with peak activation located in the right PIVC. Other higher-level motion areas including VIP showed weaker to no activation in active dodges. These results suggest that PIVC plays an active role in sensing and guiding translational egomotion that moves an observer aside from impending obstacles.
authors.affiliation: Institute for Neural Computation and rhuang@ucsd.edu.
authors.forename: Ruey-Song
authors.initials: RS
authors.lastname: Huang
authors.affiliation: Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093.
authors.forename: Ching-Fu
authors.initials: CF
authors.lastname: Chen
authors.affiliation: Cognitive, Perceptual, and Brain Sciences, University College London, London WC1E 7HX, United Kingdom, and Department of Psychological Sciences, Birkbeck-UCL Centre for NeuroImaging, Birkbeck College, University of London, London WC1H 0AP, United Kingdom.
authors.forename: Martin I
authors.identifier: http://orcid.org/0000-0002-7598-7829
authors.initials: MI
authors.lastname: Sereno
mesh_terms: D001921:Brain; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000098:blood supply / Q000502:physiology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D019370:Observation; D010100:Oxygen / Q000097:blood; D010775:Photic Stimulation; D011930:Reaction Time / Q000502:physiology; D014584:User-Computer Interface; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: avoidance; dodge; dorsal motion streams; self-motion; vestibular cortex