Changes in Cerebral Hemodynamics during Complex Motor Learning by Character Entry into Touch-Screen Terminals.
BACKGROUND
Studies of cerebral hemodynamics during motor learning have mostly focused on neurorehabilitation interventions and their effectiveness. However, only a few imaging studies of motor learning and the underlying complex cognitive processes have been performed.


METHODS
We measured cerebral hemodynamics using near-infrared spectroscopy (NIRS) in relation to acquisition patterns of motor skills in healthy subjects using character entry into a touch-screen terminal. Twenty healthy, right-handed subjects who had no previous experience with character entry using a touch-screen terminal participated in this study. They were asked to enter the characters of a randomly formed Japanese syllabary into the touch-screen terminal. All subjects performed the task with their right thumb for 15 s alternating with 25 s of rest for 30 repetitions. Performance was calculated by subtracting the number of incorrect answers from the number of correct answers, and gains in motor skills were evaluated according to the changes in performance across cycles. Behavioral and oxygenated hemoglobin concentration changes across task cycles were analyzed using Spearman's rank correlations.


RESULTS
Performance correlated positively with task cycle, thus confirming motor learning. Hemodynamic activation over the left sensorimotor cortex (SMC) showed a positive correlation with task cycle, whereas activations over the right prefrontal cortex (PFC) and supplementary motor area (SMA) showed negative correlations.


CONCLUSIONS
We suggest that increases in finger momentum with motor learning are reflected in the activity of the left SMC. We further speculate that the right PFC and SMA were activated during the early phases of motor learning, and that this activity was attenuated with learning progress.
Unit of Rehabilitation Sciences, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan; Japanese Red Cross Society Nagasaki Genbaku Hospital, Nagasaki, Japan.
Akira
A
Sagari
Unit of Rehabilitation Sciences, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan; Medical Corporation Tojinkai Miharadai Hospital, Nagasaki, Japan.
Naoki
N
Iso
Unit of Rehabilitation Sciences, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan; Medical Corporation Tojinkai Miharadai Hospital, Nagasaki, Japan.
Takefumi
T
Moriuchi
Faculty of Health and Social Work, School of Rehabilitation, Kanagawa University of Human Services, Kanagawa, Japan.
Kakuya
K
Ogahara
Center for Industry, University and Government Cooperation, Nagasaki University, Nagasaki, Japan.
Eiji
E
Kitajima
Unit of Physical and Occupational Therapy, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
Koji
K
Tanaka
Faculty of Rehabilitation Sciences, Nishikyushu University, Saga, Japan.
Takayuki
T
Tabira
Unit of Rehabilitation Sciences, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
Toshio
T
Higashi
D000328:Adult; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000098:blood supply* / Q000502:physiology; D005260:Female; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D007858:Learning / Q000502:physiology*; D008297:Male; D009048:Motor Skills / Q000502:physiology*; D019265:Spectroscopy, Near-Infrared; D014110:Touch / Q000502:physiology; D055815:Young Adult