Cerebral functional imaging using near-infrared spectroscopy during repeated performances of motor rehabilitation tasks tested on healthy subjects

• Published in: Frontiers in human neuroscience Vol. 8; p. 292
• Main Authors: Ishikuro, Koji, Urakawa, Susumu, Takamoto, Kouich, Ishikawa, Akihiro, Ono, Taketoshi, Nishijo, Hisao
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Research Foundation 13.05.2014; Frontiers Media S.A
• Subjects: Akihiro Ishikawa; Blood; Cortex (frontal); Electrical stimulation of the brain; ESB; Experiments; frontal pole; Hemoglobin; Infrared spectroscopy; Medical research; motor skill; Motor skill learning; Motor task performance; Neuroimaging; Neuroscience; NIRS; NMR; Nuclear magnetic resonance; Pharmaceutical sciences; Prefrontal cortex; Probes; Rehabilitation; Scalp; Sensorimotor system; Spectrum analysis; Studies; tDCS; Japan; NIRS; frontal pole; rehabilitation; motor skill; tDCS
• ISSN: 1662-5161; 1662-5161
• DOI: 10.3389/fnhum.2014.00292

To investigate the relationship between the frontal and sensorimotor cortices and motor learning, hemodynamic responses were recorded from the frontal and sensorimotor cortices using functional near infrared spectroscopy (NIRS) while healthy subjects performed motor learning tasks used in rehabilitation medicine. Whole-head NIRS recordings indicated that response latencies in the anterior dorsomedial prefrontal cortex (aDMPFC) were shorter than in other frontal and parietal areas. Furthermore, the increment rate of the hemodynamic responses in the aDMPFC across the eight repeated trials significantly correlated with those in the other areas, as well as with the improvement rate of task performance across the 8 repeated trials. In the second experiment, to dissociate scalp- and brain-derived hemodynamic responses, hemodynamic responses were recorded from the head over the aDMPFC using a multi-distance probe arrangement. Six probes (a single source probe and 5 detectors) were linearly placed 6 mm apart from each of the neighboring probes. Using independent component analyses of hemodynamic signals from the 5 source-detector pairs, we dissociated scalp- and brain-derived components of the hemodynamic responses. Hemodynamic responses corrected for scalp-derived responses over the aDMPFC significantly increased across the 8 trials and correlated with task performance. In the third experiment, subjects were required to perform the same task with and without transcranial direct current stimulation (tDCS) of the aDMPFC before the task. The tDCS significantly improved task performance. These results indicate that the aDMPFC is crucial for improved performance in repetitive motor learning.