title: Dissociating arbitrary stimulus-response mapping from movement planning during preparatory period: evidence from event-related functional magnetic resonance imaging.
abstract: In the present study, we aimed to dissociate the neural correlates of two subprocesses involved in the preparatory period in the context of arbitrary, prelearned stimulus-response (S-R) associations, namely, S-R mapping and movement planning (MP). We teased apart these two subprocesses by comparing three tasks in which the complexity of both S-R mapping and MP were independently manipulated: simple reaction time (SRT) task, go/no-go reaction time (GNGRT) task, and choice reaction time (CRT) task. We found that a more complex S-R mapping, which is the common element differentiating CRT and GNGRT from SRT, was associated with higher brain activation in the left superior parietal lobe (SPL). Conversely, a greater number of planned finger movements, which is the common difference between CRT and both SRT and GNGRT, was associated with higher brain activation in a number of frontal areas, including the left supplementary motor area (SMA), left dorsal premotor cortex (dPM), and left anterior cingulate cortex (ACC). The left-hemisphere dominance for S-R mapping could be related to the fact that arbitrary S-R mapping is often verbally mediated in humans. Overall, these results suggest a clear dissociation in the preparatory-set period between the more abstract role of left SPL in activating the appropriate S-R associations and the more concrete role played by the SMA, dPM, and ACC in preparing the required motor programs.
authors.affiliation: Department of Psychology, University of Western Ontario, London, Ontario, N6A 5C2, Canada. cristiana.cavina-pratesi@durham.ac.uk
authors.forename: Cristiana
authors.initials: C
authors.lastname: Cavina-Pratesi
authors.forename: Kenneth F
authors.initials: KF
authors.lastname: Valyear
authors.forename: Jody C
authors.initials: JC
authors.lastname: Culham
authors.forename: Stefan
authors.initials: S
authors.lastname: Köhler
authors.forename: Sukhvinder S
authors.initials: SS
authors.lastname: Obhi
authors.forename: Carlo Alberto
authors.initials: CA
authors.lastname: Marzi
authors.forename: Melvyn A
authors.initials: MA
authors.lastname: Goodale
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001931:Brain Mapping; D002755:Choice Behavior / Q000502:physiology; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology; D009044:Motor Cortex / Q000033:anatomy & histology / Q000098:blood supply / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D010100:Oxygen / Q000097:blood; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology*; D012016:Reference Values
chemical_list: D010100:Oxygen