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ABERRANT FUNCTIONAL CONNECTIVITY OF DL PFC AND CINGULATE NETWORKS IN PATIENTS WITH MDD DURING WORKING MEMORY PROCESSING. By Sharleen Yuan Special Topics-Affective Disorders 10.2.09. Depression affects 5% of the total population. www.cdc.gov/nchs. Depression Symptoms (more than 2 weeks).
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ABERRANT FUNCTIONAL CONNECTIVITY OF DL PFC AND CINGULATE NETWORKS IN PATIENTS WITH MDD DURING WORKING MEMORY PROCESSING By Sharleen Yuan Special Topics-Affective Disorders 10.2.09
Depression affects 5% of the total population www.cdc.gov/nchs
Depression Symptoms (more than 2 weeks) • Agitation, restlessness, and irritability • Dramatic change in appetite, often with weight gain or loss • Extreme difficulty concentrating • Fatigue and lack of energy • Feelings of hopelessness and helplessness • Feelings of worthlessness, self-hate, and inappropriate guilt • Inactivity and withdrawal from usual activities, a loss of interest or pleasure in activities that were once enjoyed (such as sex) • Thoughts of death or suicide • Trouble sleeping or excessive sleeping
Different mechanisms and systems are now being examined • Genetics • BDNF • HPA axis • Stress • Structural changes • Abnormal brain activation • DLPFC activation (main focus)
PFC anatomy and orientation Image: Caltech/Todd Hare
PFC: What does it do? • Weighs consequences of future actions • Plans and organizes those action • Integration of motor and sensory information • Executive functions • Planning and regulating behavior • Problem solver!
PFC: What else does it do? • Concerned with sequencing of behavior over time • ST “working” memory • DLPFC: Densely interconnected association regions • Projects to numerous cortical and subcortical regions
People with MDD had an increase in left DLPFC activation Matsuo, K. et al. (2007). Molecular Psychiatry, Vol 12.
Depression and DLPFC • DLPFC-striatum-thalamus circuit and frontolimbic-subcoritcal circuit • Involved in control of cognitive and executive function (DLPFC primary center) • Debate b/twn hypoactivity and hyperactivity (more now showing hyperactivity)
Depression and DLPFC • Hyperactivity of the DLPFC • Seen also in schizophrenia • Could be due to DA abnormalities • DA important in modulating prefrontal activation dur working memory • Underlie issue of abnormal function of frontolimbic network in frontolimbic circuit
Depression and DLPFC • Why is there hyperactivity? • Could be a compensatory mechanism increase WM-related activation is needed • But also found abnormalities in the ACC
Depression and ACC • Anterior cingulate cortex • Contributes to executive functions • Attention, inhibition, cognitive conflicts • Key role in emotional expression, affect regulation, and cognitive processing • Significant activation in MDD
Depression and ACC • Activated during low cognitive demand or neutral baseline • Is activation due to the cognitive task or reflect an aberrant TID? • Functional connectivity and relationship of lateral PFC and ACC not determined
Hypothesis • In MDD patients: • Abberant functional connectivity pattern in DLPFC increased TIA • Aberrant functional connectivity pattern in the ACC decreased TID
Methods • 8 males, 6 females with MDD • DSM-IV diagnosed w/o any other Axis I disorder • Pts treated w/ AD (different types) • Psychopathology rated through the BPRS, the HAMD-21, and the CGI • 7 males, 7 females in Control grp
Discussion • Two main findings: • 1. connectivity abnormalities in the DLPF/parietal network ( + correlation w the delay period of WM task) • 2. connectivity abnormalities in the VLPF/cingulate network
Discussion • Increased DLPFC suggests a compensatory recruitment • Increasing cognitive demand requires greater recruitment to maintain task performance
Discussion • Increased ACC contributes to a failure of deactivation in MDD patients • MDD patients with more deactivation of ACC showed greater clinical improvement increased activation cld represent a neg prognostic regarding clinical recovery