Neural correlates of verbalized cognition: Linking prefrontal activation under stress to the qualitative content of thought during rumination

Understanding how brain activation relates to the content of our thoughts under stress is essential for linking cognitive processes to neural mechanisms. The Think Aloud Paradigm (TAP) offers a unique, real-time method to capture verbalized cognition, enabling researchers to assess the qualitative nature of ruminative thinking. In this study, the TAP was administered prior to and following the Trier Social Stress Test (TSST) to investigate whether verbalized ruminative thought content is associated with prefrontal hypoactivation during stress. Participants' transcripts were rated on four scales: (1) rehashing bad performance, (2) speculating about negative consequences, (3) focus on negative affect, (4) reflection. Dichotomized change scores were used as group-level predictors of neural activation. Results showed that rehashing bad performance and speculating about negative consequences were significantly associated with differential activation patterns in the bilateral Inferior Frontal Gyrus (IFG) and left Dorsolateral Prefrontal Cortex (DLPFC). Interestingly, this association shows opposing patterns for each hemisphere: Specifically, participants who less frequently engage in rehashing bad performance and speculating about negative consequences show increased recruitment of the left IFG and left DLPFC under stress, whereas those who do show prefrontal hypoactivation. In contrast, participants who rehashed their poor performance showed decreased activation in the right IFG over time, while those who did not showed no significant changes. These findings suggest that ruminative thought content, as captured through TAP, is associated with reduced prefrontal engagement during stress. Future research should investigate this relationship in clinical populations to evaluate its potential for diagnostic or intervention purposes.