The most consistently identified brain regions with different imaging techniques include areas of the anterior cingulate, dorsolateral, medial and inferior prefrontal cortex, insula, superior temporal gyrus, basal ganglia and cerebellum.
In short: parts of the frontal and temporal cortex as well as the insula and cerebellum that are hypoactive in depressed subjects and in which there is increase in activity with treatment.
The Superior Temporal Gyrus
The Anterior Cingulate
The Prefrontal Cortex
Basal Ganglia and Cerebellum
How was this done?
Three separate quantitative meta-analytical studies were conducted using the Activation Likelihood Estimation technique. Analysis was performed on three types of studies: (1) those conducted at rest comparing brain activation in patients with depression and controls; (2) those involving brain changes following antidepressant treatment; and (3) those comparing brain activation patterns induced by the induction of positive or negative emotion in patients with depression compared with controls.
In publications with depressed patients and controls a total of eight areas were identified where there was decreased activation in patients compared with controls. There were also areas identified as ‘‘overactive’’ in patients included a series of deeper brain structures.
The researchers identified nine treatment papers (with 11 experiments and 78 foci) reporting areas of decreased activation following treatment and nine papers with 11 experiments and 68 foci for increased activation with treatment.
In regards to studies using happy or positive stimuli to depressed patients some showed increased activity as well as decreased activity in several brain regions for both kind of stimuli.
The researchers analysed overlapping regions leading to the results presented above.
despite the complexity and diversity of the imaging methods studied, there appears to be a pattern of distributed brain regions involved in the pathophysiology of this illness that may be identified and characterised with these techniques
Nevertheless, depression appears to involve a considerable number of diverse cortical and subcortical brain regions and there are significant differences in the way in which differing regions are abnormally active in the disorder.
Tentative, speculative but interesting, what do you think?
Paul B. Fitzgerald, Angela R. Laird, Jerome Maller, Zafiris J. Daskalakis (2008). A meta-analytic study of changes in brain activation in depression Human Brain Mapping, 29 (6), 683-695 DOI: 10.1002/hbm.20426