Functional clusters in the prefrontal cortex during mental arithmetic

Functional clustering is used to identify strongly interacting regions in the brain. In this study, functional clustering approach is applied to near infrared spectroscopy (NIRS) signals obtained during mental arithmetic task. Being a stress inducing task, mental arithmetic is known to cause a right lateral activation in the brain. We hypothesized that functional clusters would be more localized in the right prefrontal cortex. NIRS data were collected from normal healthy subjects. We found that number of functional clusters increases during task periods compared with rest and clusters are prominently located in the right prefrontal cortex. This study supports the suggestion that information theoretic approaches may be fruitful for investigating the activation patterns in the brain using NIRS.