The Corticolimbic Circuit: Disorder Flashcards
how we approach learning about disorders
(image of blind scientists trying to identify the elephant, while they touch different parts) “it’s a wall, it’s a spear, etc.” Each are right to an extent, but don’t have an understanding of the whole
lumper or splitter?
lumper, these things don’t happen in isolation
externalizing disorders
untreated distress, usually manifests itself as disruptive behavior
internalizing disorders
inward directed distress (depression, PTSD, etc.)
thought disorder
can’t keep track of information, distanced from world/ reality
how is the amygdala associated with disorders of the corticolimbic system?
usually greater amygdala activity at rest is correlated with severity of depression
major depressive disorder
a mood disorder, a sustained disturbance in predominant internal emotional experience
major depressive disorder and amygdala activity
greater amygdala activity at rest is correlated with severity of depression
what else is activated during MDD?
- greater activity in the anterior insula
- greater activity in the dorsal anterior singulate cortex
- greater activity in the pulvinar
- dACC hyperactivity
why hyperactivity in insula in MDD?
greater subjective awareness of the physiological changes
why hyperactivity in dACC in MDD?
may reflect emotional conflict in patients struggling to maintain normal relationship in face of depressive mood
- conflict monitoring
MDD and hyperactivity of the PFC
- lower vmPFC activity
- higher activity in dmPFC
failure of vmPFC to integrate signal of amygdala leads to over-attempts to regulate by the dmPFC (creates futile attempts and poor communication)
correlation between the strength of amygdala and the mPFC
less functional connectivity between amygdala and mPFC leads to a greater severity of depression (negative correlation)
treatment of amygdala
- therapy and pharmacology
SSRI treatment
proven to lower amygdala activity and thus increase functional connectivity
CBT treatment
(cognitive behavioral therapy)
greater amygdala activation to hearing negative words, but have a lesser response to them after treatment
DBS treatment
(deep brain stimulation)
- last resort treatment
electrodes are implanted deep in patients brains and targets the medial PFC
- sometimes stimulation can normalize functioning of the circuit
- but if you turn off the therapy, people will usually experience symptoms again
predictor of depression
family history of depression, high childhood anxiety
why hyperactivity of amygdala in depression?
usually anxious early in life, so a big part of neuroticism is anxiety, which makes people have a greater sensitivity to stressful life experiences
amygdala activity in GAD, MDD and both
MDD: high
GAD: elevated
both: slightly elevated