A new study led by researchers at Baylor College of Medicine delved into the brain mechanisms underlying emotion processing bias in individuals with treatment-resistant depression (TRD). The study, published in Nature Mental Health, explored the role of the amygdala and prefrontal cortex in processing emotional stimuli in TRD patients.
According to corresponding author Dr. Kelly Bijanki, the study compared signals in the amygdala and prefrontal cortex between TRD patients and epilepsy patients. The findings suggested that TRD impacts both top-down and bottom-up processing, leading to an imbalance in emotional responses. Dr. Bijanki noted, “In depressed patients, we see increased responsiveness to sad stimuli in the amygdala... We also see decreased amygdala response to happy stimuli corresponding with an increase in inhibitory activity in the orbitofrontal cortex after a processing delay.”
First author Dr. Xiaoxu Fan highlighted the significance of using human intracranial EEG in collecting the data, stating that it provided precise information about the neural dynamics of emotional processing. Dr. Bijanki added, “This allowed unprecedented insight into the precise neural dynamics of emotional processing and provides a nuanced view of the pathophysiological state underlying the disorder.”
The study also observed the effects of deep brain stimulation (DBS) on altering neural responses to emotional stimuli. Dr. Bijanki explained, “Our results show that the altered neural responses to positive information can be relieved by DBS. Additionally, DBS can change negative information processing in a different way, suggesting that DBS treatment may have different effects on positive and negative emotional processing in TRD patients.”
Looking ahead, Dr. Bijanki expressed optimism about the implications of the study for TRD patients, stating, “In the future, we hope this finding can help define the disease entity of depression, and perhaps be used as a marker of effective therapeutic response to treatment.”
The study involved a team of researchers including Madaline Mocchi, Bailey Pascuzzi, Jiayang Xiao, Brian A. Metzger, Raissa K. Mathura, Carl Hacker, Joshua A. Adkinson, Eleonora Bartoli, Salma Elhassa, Andrew J. Watrous, Yue Zhang, Anusha Allawala, Victoria Pirtle, Sanjay Mathew, Wayne Goodman, and Nader Pouratian from various institutions. The research was supported by funding from the United States National Institutes of Health.
