Caffeine differentially alters cortical hemodynamic activity during working memory: a near infrared spectroscopy...

Area of Science:

• Neuroscience
• Cognitive Science
• Pharmacology

Background:

• Caffeine is a common stimulant with known cognitive and vasoconstrictive effects.
• Its impact on the blood oxygenation level-dependent (BOLD) response is of interest in functional neuroimaging.
• Understanding caffeine's effects on cerebral hemodynamics during cognitive tasks is crucial.

Purpose of the Study:

• To investigate how caffeine affects oxy- and deoxyhemoglobin (HbO and HbR) levels during a working memory task.
• To clarify the influence of caffeine on the hemodynamic response using near-infrared spectroscopy (NIRS).

Main Methods:

• A visual 2-back working memory task was employed.
• Near-infrared spectroscopy (NIRS) was used to measure changes in HbO and HbR.
• Participants received a 200 mg dose of caffeine.

Main Results:

• Caffeine did not significantly alter working memory performance but affected reaction times in a simpler task.
• NIRS data revealed caffeine-induced changes in the hemodynamic response course.
• A significant decrease in HbO response and an increase in HbR response were observed in the inferior frontal cortex (IFC).

Conclusions:

• Caffeine's effects on brain vasculature were evident as a reduction in HbO.
• Neuronal effects, indicated by increased HbR in the left hemisphere during a verbal memory task, suggest metabolic influences.
• While behavioral effects on working memory were minimal, caffeine demonstrably impacts cerebral hemodynamics and metabolism.