Neuroimaging in Depression

Major depressive disorder also knows as clinical depression is a mood disorder that causes a persistent feeling of sadness and loss of interest associated with a dysregulation of brain regions including the prefrontal cortex and limbic system. The structural and functional relation between the abnormalities in these regions are far from understood in depressed patients. The symptoms are assumed arise from changes caused by both regions. 

Research Professor Scott Langenecker from the University of Illinois, Chicago provided a meta analysis of a fMRI study on how emotional valence modulates brain functional abnormalities in depression. His research entails The riddle of Depression: Failing to Learn and take Advantage of Optimized opportunity. It is critical to consider models of emotional dysfunction in depression, and therefore emotional valence is an important moderator when understanding neural abnormalities in depression.

At the Academic Medical Center in Amsterdam Dr. Bart de Kwaasteniet and his colleagues used a multimodal neuroimaging approach to further investigate this relationship between structural and functional abnormalities in these brain regions in depressed patients. In the meta analysis presented by Langenecker, the neuroimaging study conducted by Groenewold al et. in emotional process in depression patients was not consist with the model that describes neural association with biased emotion processing. Kwaasteniet’s and his colleagues conduced multiple neuroimagining scans of patients healthy and those with depression. They focus on the two regions that are connected by the uncinate fascicles which are know to be involved in the region of emotion.  The two regions consisted of the subgenual anterior cingulate cortex and the medial temporal lobes, which have been focused on increased activation in models describing the neural correlates of biased emotion processing in depression patients. 

This meta-analysis preformed by Groenewold al et. integrates these findings and examines whether emotional valence modulates such abnormalities since they are initially inconsistent with the model. According to their results Depressed subjects also showed reduced activity in left dorsolateral prefrontal cortex for negative stimuli and increased activity in orbitofrontal cortex for positive stimuli.

Kwaasteniet’s results from the neuroimaging scans lead him into developing a new hypothesis that  brain structure abnormalities  lead to differences in connectivity between brain areas in depressive disorder, which may have been why the meta-analysis preformed by Groenewold al et. was inconsistent with the model of neural association of biased emotion processing in depression patients. 

Elsevier. (2013, July 8). Brain structural deficits may contribute to increased functional connections 

between brain regions implicated in depression. ScienceDaily. Retrieved December 1, 2014 from 

www.sciencedaily.com/ releases/2013/07/130708103156.htm

Groenewold, N. A., Opmeer, E. M., de Jonge, P., Aleman, A., & Costafreda, S. G. (2013). Emotional 

valence modulates brain functional abnormalities in depression: evidence from a meta-analysis of 

fMRI studies. Neuroscience and Biobehavioral Reviews, 37(2), 152-63. 

10.1016/j.neubiorev.2012.11.015