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Changes in regional cerebral blood volume in frontal cortex during mental work with and without caffeine intake: functional monitoring using near-infrared spectroscopy

2004; SPIE; Volume: 9; Issue: 4 Linguagem: Inglês

10.1117/1.1755233

1560-2281

Terumasa Higashi, Yukari Sone, Kanta Ogawa, Yuri Kitamura, Kayoko Saiki, S Sagawa, Toshio Yanagida, Akitoshi Seiyama,

Blood Pressure and Hypertension Studies

Near-infrared spectroscopy (NIRS) was used to measure frontal regional cerebral blood volume (rCBV) in a person whose brain was under the influence of pharmacological agents while the person was performing a complex task. Fourteen healthy participants were administered Uchida-Kraepelin psychodiagnostic (UKP) tests before and after caffeine intake, and the concentration of caffeine in the urine was measured. The average number of answers and the average number of correct answers given by the participants improved significantly following caffeine intake. During the UKP testing, changes in the rCBV in the inferior frontal cortex were continuously measured using NIRS. The volume during the rest periods decreased as a result of caffeine-induced constriction of the cerebral arteriola. The volume increased during the mental work, but the degree of the increase was the same before and after caffeine intake. Although the performance of the mental work improved following caffeine intake, the improvement was not reflected in the rCBV in the inferior frontal cerebral cortex. These results suggest that caffeine helps to protect the brain from excessive hyperemia in addition to activating the neurons in the prefrontal cortex.