Exam 4: Affective Disorders Pt 2 Flashcards

1
Q

characteristics of depression- circadian rhythms

A

altered in depressed individuals

-these are controlled by the molecular biological clock in the suprachiasmatic nucleus of the hypothalamus

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2
Q

what systems do circadian rhythms control

A

NE, 5-HT, DA systems - may be the basis for mood dysfunction

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3
Q

depression and circadian rhythms

A

abnormal circadian rhythm in cortisol secretion

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4
Q

many depressed people fail to respond to ____

A

dexamethasone

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5
Q

dexamethasone

A

a synthetic glucocorticoid that should act as a negative feedback to suppress release of CRF and ACTH resulting in lower cortisol levels

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6
Q

the most consistent neuroendocrine abnormality in depressed individuals is an abnormal secretion of

A

cortisol
-many depressed patients have elevated cortisol levels in response to greater than normal release of ACTH and CRF

-hypersecretion most likely due to abnormal regulation of CRF by hypothalamus

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7
Q

early life traumas alter the set point for what

A

the HPA axis

  • becomes permanently over responsive
  • inc risk for depression, anxiety disorders, alcohol abuse
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8
Q

Sleep changes in MDD

A

-altered sleep is most common and persistent symptom
-onset of sleep is delayed
onset of REM sleep occurs earlier
dec i slow wave or deep sleep with repeated awakenings during the night

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9
Q

sleep changes in bipolar disorder

A

during depressive episodes: sleep resembles unipolar depression
during mania sleep is greatly reduced or absent with no loss of energy

-when manic patients are treated with a sleep inducing benzo manic symptoms subside

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10
Q

PET scans of blood flow in depressed patients show inc activity where

A

orbitofrontal cortex and amygdala

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11
Q

inc metabolic activity in amygdala correlated with

A

severity of depression and returns to normal after antidepressant drug treatment

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12
Q

corticolimbic changes in MDD amygdala and ACC

A

amygdala: at rest and in response to danger
ACC: emotional conflict-should I be happy or sad about this

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13
Q

corticolimbic changes in MDD

hyperactivity in dorsomedial PFC

A

dmPFC: judgement and decision making-tells amygdala we are fine
weakened connectivity between dmPFC and amygdala in depressed individuals
-failure to properly regulate amygdala response in depressed individuals

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14
Q

insula in MDD

A

hyperactive, more aware of body states, inc HR bc nervous, pit in stomach

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15
Q

thalamus (PVN) in MDD

A

visual relay of thalamus activated when viewing emotional faces
-good at picking up on emotions of others - why they think so many people upset with them

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16
Q

depression is associated with lack of cortical control over what

A

the limbic system

  • resting state fMRI shows successful treatment is associated with inc connectivity btw PFC and limbic areas
  • antidepressants inc connectivity
17
Q

glucocorticoid hypothesis

A

focuses on stress-related neuroendocrine abnormalities of depression
-depressed patients have abnormally high CRH secretion from HPA axis

18
Q

HPA axis

A

amygdala stimulates HPA axis activity

hippocampus has inhibitory control

19
Q

hippocampus and depression

A

-involved in shutting down activity of HPA axis - overrides and shuts down amygdala induced HPA activity to limit duration of stress response

20
Q

when stress is prolonged and intense, glucocorticoid levels remain high and what happens

A

hippocampal neurons are damaged
-can no longer regulate stress response

damage: dec dendritic branches and spines in PFC and hipocampus
formation of new hippocampal cells is inhibited
-dec neurogenesis and dec BDNF

21
Q

antidepressants have what actions involvig hippocampus and depression

A

reduce CRH levels and reverse loss of hippocampal dendrites in animal studies

22
Q

Hippocampal BDNF and depression

A

BDNF is low in hippocampus and PFC
dec BDNF due to genetic polymorphisms associated with depression
chronic stress dec BDNF in hippocampus
chronic antidepressant treatment inc BDNF
antidepressants prevent stress induced reduction in BDNF and neuronal atrophy - protect brai from stress

23
Q

changes in brain with bipolar disorder - mania

A
  • PET scans show inc brain activity in manic episodes
  • some similarities with schizophrenia like enlarged ventricles (meaning tissue death)
  • altered corticolimbic activity (connectivity reduced)
24
Q

changes in amygdala function throughout bipolar stages

A

hyperactivity in resonse to emotional faces in mania - euphoria, insomnia, inattention, distractibility

  • dec amygdala function during depressive episodes
  • dec activity in ventrolateral PFC in all stages (less contorl of amygdala in bipolar patients)

functional connectivity btw vlPFC and amygdala - poor reguation in Bipolar patiens