Brain Lateralization of Emotional Processing in Depression

Abstract

Lateralization is the idea that the two halves of the brain -left and right hemispheres -execute different functions. This study employed small-N design involving 4 male patients (2 anxious) and (2 depressed with left and right hemispheres dominance). In Study1, the emotional processing was done during the PET scan which lasted for 10 minutes. In Study 2, emotional processing was conducted using the Self-Assessment Manikin (SAM). PET brain scan images revealed that both the LHDAP and RHDAP had hyper metabolism in the right sensor motor cortex while LHDDP had hyper metabolism in the left midfrontal cortex and left associative visual cortex and the RHDDP had hyper metabolism in the right primary visual cortex. On the SAM, RHDAP revealed happy emotion with the pleasant picture and felt in control with the unpleasant picture while the LHDAP revealed neither happy nor unhappy with the pleasant picture and dominated with the unpleasant picture. On the other hand both LHDDP and RHDDP revealed quite happy feelings with the pleasant picture and felt dominated with the unpleasant picture. This implied that anxious patients processed emotions in the right hemisphere regardless of valence while depressed patients processed their emotions based on their brain dominance.