There is some scientific research that has found changes in brain structure and function in individuals with depression. Specifically, changes in the communication between brain regions known to be involved in emotional expression. There is some discrepancy within the field as to whether these brain changes cause depression or vice versa.
particularly Functional Magnetic Resonance Imaging (fMRI) has been used in some neurological research to try and establish how the brains of depressed patients react to negative situations in comparison to non-depressed brains.
Some research has examined the connections between the pre-frontal cortex (pFC) of the brain and the amygdala. The former is an area of the brain thought to be involved in the regulation of emotions and the latter, a small almond shaped part of the brain, believed to be directly involved in the processing of emotions and instigator of subsequent physiological-emotional responses.
The majority of findings suggest that individuals diagnosed with depression have abnormal emotional processing between these two regions in the brain. However, it remains an area of scientific argument as to whether the brain structural and functional changes cause depression episodes or arise as a result of suffering from depression.