Neural Correlates of Identity Judgments in the Prefrontal Cortex: An Optical Brain Imaging (fNIRS) Study

The prefrontal cortex is one of the important brain regions involved during human reasoning and decision-making processes. Neuroimaging studies have indicated that conflicting situations cause higher activation in the prefrontal as well as in the anterior cingulate cortex (ACC) (Botvinick et al., 2004; Kerns et al., 2004). The current study focuses on prefrontal activity in participants' reasoning processes when judging propositions related to identity, e.g., "A piece of paper bent over three times is the same/different" on a 5-point Likert-scale. The obtained optical brain imaging (fNIRS) results indicate that participants experience higher levels of conflict for propositions they strongly disagree with as opposed to propositions they strongly agree with. Moreover, indeterminate responses were observed to cause higher levels of activation in prefrontal regions. Additionally, the behavioral data relying on reaction times of the participants imply that there are significant differences related to the content of the responses.