Exploring the role of primary and supplementary motor areas in simple motor tasks with fNIRS.
Studies employing functional magnetic resonance imaging (fMRI) have highlighted a covariation between the amplitude of hemodynamic responses recorded in primary and supplementary motor areas (M1 and SMA) and the duration of a motor task. A subset of these studies have hinted to a possible functional dissociation between processing carried out in these areas, with SMA primarily involved in action preparation, while M1 involved in action execution. This proposed functional dissociation was explored in the present study using a different technique--functional near-infrared spectroscopy--which enabled a finer-grained monitoring of the temporal characteristics of the hemodynamic response compared to fMRI. Here, hemodynamic responses in M1 and SMA were recorded in 7 participants during a right-finger-tapping task of short (1 s) or long (3 s) duration. Hemodynamic responses of larger amplitude were recorded from both contralateral M1 and SMA during long-duration than short-duration tapping. Furthermore, the analysis of the temporal profiles of these responses revealed a more sustained and prolonged activity for long-duration versus short-duration tapping in M1, but not in SMA. Rather than functionally dissociable areas, the present results are more compatible with the hypothesis that M1 and SMA subserve different, though strongly interacting, functional subroutines subtended in motor task preparation and execution.
Department of Developmental Psychology, University of Padova, Padova, Italy.
Sabrina
S
Brigadoi
Simone
S
Cutini
Fabio
F
Scarpa
Pietro
P
Scatturin
Roberto
R
Dell'Acqua
D000328:Adult; D000704:Analysis of Variance; D001931:Brain Mapping; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009044:Motor Cortex / Q000378:metabolism* / Q000502:physiology; D009068:Movement / Q000502:physiology*; D010108:Oxyhemoglobins / Q000378:metabolism; D010775:Photic Stimulation; D019265:Spectroscopy, Near-Infrared; D013997:Time Factors; D055815:Young Adult
D006454:Hemoglobins; D010108:Oxyhemoglobins; C100003:deoxyhemoglobin