The emotional counting Stroop paradigm: a functional magnetic resonance imaging probe of the anterior cingulate affective division.

The emotional counting Stroop (ecStroop) functional magnetic resonance imaging (fMRI) activation paradigm was designed to recruit the anterior cingulate affective division (ACad). Nine normal, healthy male and female subjects (mean age 24.2 years) reported via button press the number of neutral and negative words that appeared on a screen while reaction time and fMRI data were acquired. We observed a) greater ACad activation for negative versus neutral words during initial presentation blocks; b) lower overall ACad signal intensity during task performance (i.e., both negative and neutral words) compared to the baseline fixation condition; and c) no reaction time increase to negative versus neutral words. In a companion study of a cognitive version of the counting Stroop (Bush et al 1998), these same 9 subjects a) activated the more dorsal anterior cingulate cognitive division; b) also showed the overall decrease in ACad signal intensity; and c) demonstrated a reliable reaction time effect. Taken together, these data offer a within-group spatial dissociation of AC function based upon information content (i.e., cognitive vs. emotional) and/or presence of behavioral interference. We propose that the ecStroop will be a useful fMRI probe of ACad function in anxiety disorders.