A functional magnetic resonance imaging study of verbal working memory in young people at increased familial risk of depression.
Mannie ZN., Harmer CJ., Cowen PJ., Norbury R.
BACKGROUND: Patients with depression show abnormalities in the neural circuitry supporting working memory. These abnormalities apparently persist into clinical remission, raising the possibility that they might be trait markers indicating vulnerability to depression. METHODS: We studied 17 young people who had a depressed parent but no personal history of depressive illness (FH) and 15 healthy control subjects with no family history of depression. Participants performed a verbal working memory task of varying cognitive load (n-back) while undergoing functional magnetic resonance imaging scanning. We used multiple regression analyses to assess overall capacity (1-, 2-, 3-back vs. 0-back) as well as linear and quadratic modulation of cognitive demand. RESULTS: Performance accuracy and response latency did not differ between groups, and overall capacity was similar. However, for both linear and quadratic load response activity, FH participants showed greater activation in lateral occipital cortex, superior temporal cortex, and superior parietal cortex. CONCLUSIONS: Our data suggest that, as in depressed patients, maintenance of task performance in FH participants is associated with a significant increase in the load-response activity of the cortical regions involved in working memory. This neural abnormality could form part of the predisposition to develop depressive disorders.