Hemodynamic Changes in the Prefrontal Cortex in Smooth and Non-smooth Performance Measured by Near-Infrared Spectroscopy
Year: 2007
Type: article
Abstract: Hemodynamic Changes in the Prefrontal Cortex in Smooth and Non-smooth Performance Measured by Near-Infrared Spectroscopy (NIRS) Shintaro Shinozaki † , Harumi Kobayashi ‡ , and Tetsuya Yasuda ¶ Graduate School of Human-Social Informatics, Tokyo Denki University Hatoyama-cho, Hiki-gun, Saitama 350-0394, Japan Email: [email protected] ‡ Email: [email protected] Email: [email protected] Keywords: attentional demand, mirror drawing, prefrontal cortex, near-infrared spectroscopy Results and Discussion We calculated the Z-scores of oxy-Hb and total-Hb for each channel within a participant. We defined the participant did a smooth performance without hesitation if he continuously manipulated the joystick for 0.5 s or more. A continuous manipulation of less than 0.5 s was a performance with hesitation. If the participant drew a line in the appropriate course for 1 or more than 1 s, it was an “on-course” performance. For 1 or less than 1 s, it was an “off-course” performance. The tracing time of on-course performance increased while off-course performance decreased as the participant repeated the task. The Table 1 shows the number of more activated channels compared with baseline and the means of the Z-scores of oxy-Hb and total-Hb. It was found that 1) in the performance type of on-course with hesitation, fewer channels of prefrontal cortex were activated relative to other performance types, and these channels were activated only in the last two trials. Attention demands in this performance may be different from those of other performance types, 2) activation generally decreased in other performance types, and this decrease seemed to be more evident in the right hemisphere. Introduction Prefrontal cortex is active during new learning of a skill but not active during automatic performance of a learned skill (Jueptner, et al., 1997). Rowe, et al. (2002) showed attention to action increased activity in prefrontal cortex. These results seem to indicate that attention is required early in skill learning, but that attention demands decrease as a person becomes more skilled. Previous studies used sequential movements. In this study, we used computerized mirror drawing task measured by near-infrared spectroscopy to allow our participants relatively free and natural movements. We could also identify the different performance types, specifically, smooth and skilled performance and non-smooth and less skilled performance and clarify the relations between performance types and the activation of the prefrontal cortex. Method Participants The participants were 9 healthy volunteers (age range 23- 25). They are all right-handed. Procedure The participants were asked to control a joystick by their right hand to trace a mirror image of a star-shape (about 12 cm width on the computer monitor) that was drawn by two lines of an inner, smaller star and a surrounding larger star. They were asked to trace the star without touching or crossing the two lines that were 7 mm apart. International 10-20 System was used to determine Fz and overall position of the probes were set in such a way that the activation of the prefrontal cortex could be investigated in each hemisphere. Changes in the concentration of oxy-, deoxy-Hb, and total Hb (sum of oxy- and deoxy-Hb) were measured by near-infrared spectroscopy (NIRS, ETG-4000 system, Hitachi Medical Corporation, Tokyo, Japan) Figure 1. Probe set up There were 4 sets of 40 seconds of mirror drawing task and 80 seconds of rest and 10 seconds of baseline periods. Table 1. The total number of activated channels and means of Z-scores in different performance types Acknowledgments This study was supported by the 21st Century Center of Excellence Program “Human Adaptive Mechatronics,” at Tokyo Denki University. References Jueptner, M., K. M. Stephan, C. D. Frith, D. J. Brooks, R.S.J. Frackowiak, and R. E. Passingham. Anatomy of motor learning. I. Frontal cortex and attention to action. J. Neurophysiol. 77: 1313-1324, 1997. Rowe J, Frackowiak RSJ, Friston K, Passingham RE. Attention to action: specific modulation of cortico-cortical interactions in humans. NeuroImage 17, 988-998, 2002.
Authors: Shintaro Shinozaki, Harumi Kobayashi, T. Yasuda
Institution: Tokyo Denki University
Language: English
Subfield: Radiology, Nuclear Medicine and Imaging
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W2587142950