Measurement of brain function during procedural memory tasks using near-infrared optical topography

• Project/Area Number: 16500368
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Rehabilitation science/Welfare engineering
• Research Institution: University of Occupational and Environmental Health, Japan
• Principal Investigator: OKAZAKI Tetsuya University of Occupational and Environmental Health, Japan, School of Medicine, Assistant Professor, 医学部, 講師 (40352314)
• Co-Investigator(Kenkyū-buntansha): HACHISUKA Kenji University of Occupational and Environmental Health, Japan, School of Medicine, Professor, 医学部, 教授 (00129602)
• Project Period (FY): 2004 – 2005
• Project Status: Completed (Fiscal Year 2005)
• Budget Amount: ¥1,900,000 (Direct Cost: ¥1,900,000); Fiscal Year 2005: ¥900,000 (Direct Cost: ¥900,000); Fiscal Year 2004: ¥1,000,000 (Direct Cost: ¥1,000,000)
• Keywords: Near-infrared spectroscopy / Optical topography / Procedural memory / Frontal lobe / 光トポグラフィ

Research Abstract

1.Objectives : The present study aimed to investigate brain activation during procedural memory tasks using optical topography
2.Subjects : Subjects were 9 healthy adult persons (5 males, 4 females ; 24.6±3.4 years old). They had never experienced after-mentioned procedural memory tasks.
3.Methods : (1)Procedural memory tasks : procedural memory was assessed by following three tasks ; mirror reading, mirror drawing, and tower of Toronto puzzle. Each task consisted of sessions 1 to 3 performed on three consecutive days, and each session included 3 trials. (2)Optical topography : Optical topography measurement was performed using ETG-100, a 24-channel near-infrared spectroscopy (NIRS) system (Hitachi Medical Corporation, Tokyo, Japan). We placed plastic holder with 15 probes on a subject's forehead. As a control task for each procedural memory task, we adopted normal image reading, direct sight drawing, and disc transfer in an orderly way. Optical topography measurement was performed on da y 1 (before sessions 1) and day 3 (after session 3).
4.Results and Discussion : (1)procedural memory : In each subject, each three task performance improved by the day. (2)Optical topography : On day 1, increase of concentration change of oxy-hemoglobin was found in prefrontal cortex during each three procedural memory tasks. On day 3, increase of concentration change of oxy-hemoglobin was fewer than on day1 during each three procedural memory task.
About difference of oxy-hemoglobin change pattern among three procedural memory tasks and between before and after skill learning, we need the careful interpretation
5.Conclusins : The present study showed that optical topography could demonstrate prefrontal activation during procedural memory tasks that we employ in clinical setting. This methodology has not much limitation in measurement place, subject's posture and body movement. Considering the above advantages, optical topography is assumed to be useful tool for complementary approach with conventional neuropsychological study and another brain imaging study.