title: Inhibitory motor control in response stopping and response switching.
abstract: While much is known about the neural regions recruited in the human brain when a dominant motor response becomes inappropriate and must be stopped, less is known about the regions that support switching to a new, appropriate, response. Using functional magnetic resonance imaging with two variants of the stop-signal paradigm that require either stopping altogether or switching to a different response, we examined the brain systems involved in these two forms of executive control. Both stopping trials and switching trials showed common recruitment of the right inferior frontal gyrus, presupplementary motor area, and midbrain. Contrasting switching trials with stopping trials showed activation similar to that observed on response trials (where the initial response remains appropriate and no control is invoked), whereas there were no regions that showed significantly greater activity for stopping trials compared with switching trials. These results show that response switching can be supported by the same neural systems as response inhibition, and suggest that the same mechanism of rapid, nonselective response inhibition that is thought to support speeded response stopping can also support speeded response switching when paired with execution of the new, appropriate, response.
authors.affiliation: Department of Psychology, University of California, Los Angeles, Los Angeles, California 90095-1563, USA. nmk@ucla.edu
authors.forename: Naomi M
authors.initials: NM
authors.lastname: Kenner
authors.forename: Jeanette A
authors.initials: JA
authors.lastname: Mumford
authors.forename: Rebecca E
authors.initials: RE
authors.lastname: Hommer
authors.forename: Martha
authors.initials: M
authors.lastname: Skup
authors.forename: Ellen
authors.initials: E
authors.lastname: Leibenluft
authors.forename: Russell A
authors.initials: RA
authors.lastname: Poldrack
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology; D001931:Brain Mapping; D056344:Executive Function / Q000502:physiology*; D005260:Female; D005625:Frontal Lobe / Q000502:physiology*; D006801:Humans; D007266:Inhibition, Psychological; D008279:Magnetic Resonance Imaging; D008297:Male; D008636:Mesencephalon / Q000502:physiology*; D009044:Motor Cortex / Q000502:physiology*; D009433:Neural Inhibition / Q000502:physiology; D009434:Neural Pathways / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology