Abnormal hippocampal activation in patients with extensive history of major depression: an fMRI study

Brain activation induced by chronic psychosocial stress in mice

“…In patients with MDD the vHP is less active during a memory task 8 , but more active at rest 7 compared to healthy controls, while the PFC exhibits decreased activity at rest 6 . Both regions are activated in humans during an acutely stressful task 44,45 .…”

“…Stress-related mental disorders like major depressive disorder (MDD) and anxiety disorders are associated with altered activation of specific brain regions. For example, neuroimaging has revealed that resting-state activity is reduced in the prefrontal cortex (PFC) 6 and increased in the hippocampus 7 while task-related reactivity is decreased in the hippocampus 8 and nucleus accumbens 9 of MDD patients. Interpretation of the human imaging findings is difficult as activation patterns in tasks carried out during brain imaging may differ from those occurring during naturalistic chronic stress exposure.…”

Systematic review of the neural basis of social cognition in patients with mood disorders

“…47,62,163,164 They may stem from different emotional processing paradigms and from differences in the clinical status of patients in terms of medication use, illness burden, comorbidity and depression severity. For example, Scheuerecker and colleagues 69 recruited a heterogeneous sample of patients experiencing first-episode and recurrent depression and failed to find differences from controls in patterns of neural activation in response to emotional faces; given earlier behavioural and neuroimaging findings that cognitive processing is more vulnerable to disruption in patients with recurrent mood disorders than in first-episode patients (for example, see MacQueen and colleagues, 165 Basso and Bornstein, 166 Lebowitz and colleagues, 167 Milne and colleagues 168 and vanGorp and colleagues this null finding stemmed from the inclusion of first-episode patients in the mood disorders group. Actively depressed patients also show increased neural responses to positive and negative facial expressions in the subgenual portion of the anterior cingulate cortex, a region involved in the physiologic response of emotional processing.…”

Cognitive impairment in major depression and the mGlu2 receptor as a therapeutic target

“…A strong relationship between hippocampal activation and encoding success is expected in healthy subjects. In MDD patients, failure of hippocampal activation occurs during the encoding phase in non-emotional memory task (Bremner et al, 2004) and during impaired recollection performance in subjects with repeated episodes of MDD (Milne et al, 2012), but not in firstepisode MDD patients (van Eijndhoven et al, 2012). A single dedicated study in MDD patients designed to test memory deficits driven by hippocampal dysfunction found changes in activity specific to the hippocampus, which did not result from overall network deficits or motivational disparities between MDD and control populations (Fairhall et al, 2010).…”