Brain activation before and after cognitive-behavior therapy in first-episode patients with mild-to-moderate major depressive disorder

Abstract

Objective To explore the neurobiological mechanisms underlying cognitive-behavior therapy（CBT）for major depressive disorder（MDD） by detecting the neural changes of patients following CBT. Methods Thirteen first-episode treatment-naive patients with MDD and 13 matched healthy volunteers underwent fMRI scan. All the patients were treated with 6-week CBT only and scanned again after treatment. A gender recognition task with neutral, positive and negative expressions was performed by all subjects during each scan. The fMRI data was processed by SPM8 to detect the brain activation in negative and positive condition. Results In negative condition, patients showed decrease of activation in right cerebellum and postcentral gyrus compared to the healthy. After treatment, the activation in vermis was still lower in patients than the healthy. The patients exhibited increased activation in left fusiform gyrus, right insula, left caudate, right middle frontal gyrus and inferior parietal lobule after treatment, and reversed activation in left precentral gyrus （Montreal Neurological Institute（x,y,z）: -54，0，21，t=4.67,P＜0.05）, right opercular part of inferior frontal gyrus (Montreal Neurological Institute（x,y,z）: 48，15，15，t=5.10,P＜0.05） and bilateral supramarginal gyrus (right:Montreal Neurological Institute（x,y,z）: 54，-21，27，t=5.19；left: Montreal Neurological Institute（x,y,z）: -60，-24，33，t=4.81；P＜0.05） to positive expressions. Conclusion CBT may work via down-regulation of response inhibition systems and up-regulation of emotional processing and cognitive monitor system. Key words: Cognitive therapy; Magnetic resonance imaging; Depressive disorder; Task-state