Measuring prefrontal brain activity during verbal fluency tasks using functional near infrared spectroscopy

Area of Science:

• Neuroscience
• Cognitive Psychology
• Neuroimaging

Background:

• Verbal fluency (VF) tasks assess executive function, language, and processing speed.
• Letter fluency (LF) and semantic fluency (SF) tap distinct cognitive processes and neural correlates.
• LF is linked to executive functions, while SF is associated with linguistic abilities.

Purpose of the Study:

• Compare prefrontal cortex (PFC) activation during LF and SF tasks.
• Investigate the relevance of both VF tasks to frontal systems.
• Explore clinical applications of combining VF tasks with neuroimaging.

Main Methods:

• Utilized functional near-infrared spectroscopy (fNIRS) to measure cortical hemodynamic changes.
• Twenty-six English-speaking undergraduates participated in the study.
• Participants completed three LF and three SF tasks, with activation compared to baseline.

Main Results:

• LF tasks showed greater activation in anterior PFC regions.
• SF tasks demonstrated increased activation in left posterior PFC regions.
• Both LF and SF tasks resulted in diffuse PFC activation compared to baseline.

Conclusions:

• PFC activation is evident during both LF and SF tasks.
• Findings suggest distinct PFC engagement patterns for different verbal fluency types.
• Combining fNIRS with cognitive tests like VF holds potential for clinical assessment.