Exam 4: Affective Disorders Pt 2

Question 1

characteristics of depression- circadian rhythms

Answer 1

altered in depressed individuals

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

Question 2

what systems do circadian rhythms control

Answer 2

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

Question 3

depression and circadian rhythms

Answer 3

abnormal circadian rhythm in cortisol secretion

Question 4

many depressed people fail to respond to ____

Answer 4

dexamethasone

Question 5

dexamethasone

Answer 5

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

Question 6

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

Answer 6

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

Question 7

early life traumas alter the set point for what

Answer 7

the HPA axis

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

Question 8

Sleep changes in MDD

Answer 8

-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

Question 9

sleep changes in bipolar disorder

Answer 9

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

Question 10

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

Answer 10

orbitofrontal cortex and amygdala

Question 11

inc metabolic activity in amygdala correlated with

Answer 11

severity of depression and returns to normal after antidepressant drug treatment

Question 12

corticolimbic changes in MDD amygdala and ACC

Answer 12

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

Question 13

corticolimbic changes in MDD

hyperactivity in dorsomedial PFC

Answer 13

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

Question 14

insula in MDD

Answer 14

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

Question 15

thalamus (PVN) in MDD

Answer 15

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

Question 16

depression is associated with lack of cortical control over what

Answer 16

the limbic system

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

Question 17

glucocorticoid hypothesis

Answer 17

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

Question 18

HPA axis

Answer 18

amygdala stimulates HPA axis activity

hippocampus has inhibitory control

Question 19

hippocampus and depression

Answer 19

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

Question 20

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

Answer 20

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

Question 21

antidepressants have what actions involvig hippocampus and depression

Answer 21

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

Question 22

Hippocampal BDNF and depression

Answer 22

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

Question 23

changes in brain with bipolar disorder - mania

Answer 23

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

Question 24

changes in amygdala function throughout bipolar stages

Answer 24

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