title: The role of the human ventral premotor cortex in counting successive stimuli.
abstract: Adult humans have the ability to count large numbers of successive stimuli exactly. What brain areas underlie this uniquely human process? To identify the candidate brain areas, we first used functional magnetic resonance imaging, and found that the upper part of the left ventral premotor cortex was preferentially activated during counting of successive sensory stimuli presented 10-22 times, while the area was not activated during small number counting up to 4. We then used transcranial magnetic stimulation to assess the necessity of this area, and found that stimulation of this area preferentially disrupted subjects' exact large number enumeration. Stimulation to the area affected neither subjects' number word perception nor their ability to perform a non-numerical sequential letter task. While further investigation is necessary to determine the precise role of the left ventral premotor cortex, the results suggest that the area is indispensably involved for large number counting of successive stimuli, at least for the types of tasks in this study.
authors.affiliation: Human Motor Control Section, Medical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892-1428, USA. kansakuk@rehab.go.jp
authors.forename: Kenji
authors.initials: K
authors.lastname: Kansaku
authors.forename: Benjamin
authors.initials: B
authors.lastname: Carver
authors.forename: Ari
authors.initials: A
authors.lastname: Johnson
authors.forename: Keiji
authors.initials: K
authors.lastname: Matsuda
authors.forename: Norihiro
authors.initials: N
authors.lastname: Sadato
authors.forename: Mark
authors.initials: M
authors.lastname: Hallett
mesh_terms: D000328:Adult; D016477:Artifacts; D001931:Brain Mapping; D003071:Cognition / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008433:Mathematics; D008568:Memory / Q000502:physiology; D009044:Motor Cortex / Q000033:anatomy & histology / Q000502:physiology*; D010775:Photic Stimulation; D011932:Reading; D050781:Transcranial Magnetic Stimulation; D014705:Verbal Behavior / Q000502:physiology