This study, conducted by Barreiros et al., investigates the role of the rostral anterior cingulate cortex (rACC) in treatment-resistant depression through analyzing its functional connectivity under emotional stimuli. 93 subjects were recruited to participate in this study, and among them, they were split into 3 groups - treatment-resistant depression (n = 31), treatment-sensitive depression (n = 35), and healthy controls (n = 37). fMRI data was collected from the subjects as they performed tasks to elicit emotional responses, and the data was analyzed. From the results, it was found that for stimuli above the threshold for consciousness, treatment-resistant depression patients experienced significantly less connectivity between the rACC and the hippocampus than treatment-sensitive depression subjects (p < 0.01) and control subjects (p < 0.05). For subliminal emotional stimuli, it was found that treatment-resistant depression subjects had greater functional connectivity between the rACC and cerebellum compared to the treatment-sensitive depression (p < 0.01) and control (p < 0.05) groups, and treatment-resistant depression subjects had lower functional connectivity between the rACC and temporal fusiform gyrus than the treatment-sensitive depression (p < 0.05) and control (p < 0.01) groups. In terms of rACC - distal anterior cingulate cortex (dACC) connectivity under subliminal stimulus, no significant difference was observed between the depression groups, but both depression groups had greater connectivity between the rACC and the dACC than the control group (r < 0.05).