Activation of the prefrontal cortex during the Trail‐Making Test detected with multichannel near‐infrared spectroscopy

TLDR

The Trail‑Making Test (TMT) evaluates executive function, with Part B probing complex processes such as cognitive set shifting, which are thought to involve the prefrontal cortex. The study aimed to investigate prefrontal cortex activation during TMT Parts A and B using multichannel near‑infrared spectroscopy. Forty‑one healthy right‑handed volunteers were scanned with a 22‑channel NIRS system to record prefrontal hemodynamic changes while performing the TMT. NIRS revealed a greater increase in oxygenated hemoglobin in the prefrontal cortex during TMT Part B compared to Part A, with 27 of 41 subjects showing bilateral activation, indicating that PFC activity reflects executive functions such as set shifting.

Abstract

Abstract The Trail‐Making Test (TMT) is a neuropsychological test for evaluating executive function, and the TMT Part B reflects more complex cognitive processes including cognitive set shifting. The prefrontal cortex (PFC) is thought to be involved in these cognitive processes. The purpose of the present paper was to investigate PFC activation during performance of the TMT Part A and Part B using multichannel near‐infrared spectroscopy (NIRS). Subjects were 41 healthy right‐handed volunteers. The hemodynamic changes in the PFC during the TMT were measured on a 22‐channel NIRS machine. The subjects had a greater increase of oxygenated hemoglobin ([oxyHb]) during the TMT Part B than during Part A in the PFC. Twenty‐seven out of the 41 subjects had a bilateral increase of [oxyHb] in the PFC during Part B according to laterality index. NIRS detected activation in the PFC during the performance of the TMT Part B and this PFC activation may reflect executive functions including cognitive set shifting involved in the TMT Part B.