title: Motion standstill leads to activation of inferior parietal lobe.
abstract: Previous studies on motion perception revealed motion-processing brain areas sensitive to changes in luminance and texture (low-level) and changes in salience (high-level). The present functional magnetic resonance imaging (fMRI) study focused on motion standstill. This phenomenon, occurring at fast presentation frequencies of visual moving objects that are perceived as static, has not been previously explored by neuroimaging techniques. Thirteen subjects were investigated while perceiving apparent motion at 4 Hz, at 30 Hz (motion standstill), isoluminant static and flickering stimuli, fixation cross, and blank screen, presented randomly and balanced for rapid event-related fMRI design. Blood oxygenation level-dependent (BOLD) signal in the occipito-temporal brain region MT/V5 increased during apparent motion perception. Here we could demonstrate that brain areas like the posterior part of the right inferior parietal lobule (IPL) demonstrated higher BOLD-signal during motion standstill. These findings suggest that the activation of higher-order motion areas is elicited by apparent motion at high presentation rates (motion standstill). We interpret this observation as a manifestation of an orienting reaction in IPL towards stimulus motion that might be detected but not resolved by other motion-processing areas (i.e., MT/V5).
authors.affiliation: Department of Psychiatric Neurophysiology, University Hospital of Clinical Psychiatry, Bern, Switzerland. federspiel@puk.unibe.ch
authors.forename: Andrea
authors.initials: A
authors.lastname: Federspiel
authors.forename: Umberto
authors.initials: U
authors.lastname: Volpe
authors.forename: Helge
authors.initials: H
authors.lastname: Horn
authors.forename: Thomas
authors.initials: T
authors.lastname: Dierks
authors.forename: Anders
authors.initials: A
authors.lastname: Franck
authors.forename: Patrizia
authors.initials: P
authors.lastname: Vannini
authors.forename: Lars-Olof
authors.initials: LO
authors.lastname: Wahlund
authors.forename: Silvana
authors.initials: S
authors.lastname: Galderisi
authors.forename: Mario
authors.initials: M
authors.lastname: Maj
mesh_terms: D000328:Adult; D001931:Brain Mapping; D002560:Cerebrovascular Circulation / Q000502:physiology; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D009415:Nerve Net / Q000033:anatomy & histology / Q000502:physiology; D010296:Parietal Lobe / Q000033:anatomy & histology / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation; D014793:Visual Cortex / Q000033:anatomy & histology / Q000502:physiology; D014795:Visual Pathways / Q000033:anatomy & histology / Q000502:physiology*