Mood Disorders & Emotion Circuits

Question 1

After receiving contextual information from the brain and sensory inputs from the body, where does the hypothalamus control outputs?

Answer 1

Autonomic Nervous System & Pituitary Gland (HPA axis)

Question 2

What kind of influence does the cortex exert on the hypothalamus? What does this mean?

Answer 2

The cortex exerts an inhibiting influence on the hypothalamus which means that the subjective expression of emotion requires the cortex, while the visceral expression of emotional behaviors involves descending pathways from the hypothalamus.

Question 3

Parasympathetics have long _______ with ganglia near the _______ _______. Sympathetics have long _______ with ganglia near the ______ _____.

Answer 3

Parasympathetics have long pre-ganglionics with ganglia near the target organ.
Sympathetics have long post-ganglionics with ganglia near the spinal cord.

Question 4

What NT do all pre-ganglionics use?

Answer 4

Cholinergic

Question 5

What NT do post-ganglionics have?

Answer 5

Parasympathetic: Cholinergic
Sympathetic: Adregneric

Question 6

What is the hypothalamic-pituitary-adrenal axis? (HPA)

Answer 6

The hypothalamus stimulates release of NT from the anterior pituitary which stimulates the adrenal cortex to produce glucocorticoids which activates the body’s stress response.

Question 7

What are the limbic areas involved in emotion and mood?

Answer 7

Cingulate gyrus, ventral striatum=nucleus accumbens, hypothalamus, amygdala, hippocampus

Question 8

What is the overall effect of fear circuits?

Answer 8

Overall effect = arousal, vigilance - enhanced memories (so that we remember what situation caused the danger)

Question 9

What is the cue versus context?

Answer 9

snake –> amygdala triggers fear response

zoo –> cortex & hippocampus dampens down the fear

Question 10

What area of the brain makes dopamine?

Answer 10

Substantia nigra & ventral tegmental area

Question 11

What part of the brain makes norepinephrine?

Answer 11

Locus Coeruleus

Question 12

What part of the brain make serotonin?

Answer 12

Raphe Nuclei

Question 13

What are the reuptake enzymes?

Answer 13

DAT= dopamine transporter 
NET= norepinephrine transporter
SERT= serotonin transporter

Question 14

What is MAO?

Answer 14

monoamine oxidase for enzymatic degradation on intracellular presynaptic cell or synaptic cleft

Question 15

What is COMT?

Answer 15

degrades catecholamines in synaptic cleft and pre- and post- synaptic cells

Question 16

What are treatments for anxiety?

Answer 16

Non-drug
1. CBT
2. eye movement desensitization & reprocessing 
Drugs that Act on GABA pathways
Antidepressants 
Beta-blockers

Question 17

What is the diagnostic criteria for Bipolar Disorder?

Answer 17

Depression symptoms + mania symptoms

Question 18

What are the structural changes seen in depression?

Answer 18

Decreased gray matter volume & functioning in the prefrontal cortex and hippocampus. Pyramidal neurons are smaller and loss of GABAergic interneurons. Hippocampal atrophy, increased activity in amygdala (bigger cell bodies & more dendritic branching). The Anterior cingulate cortex may be activated

Question 19

What does lithium do in depression?

Answer 19

Lithium strengthens both pre- and post- synaptic activity of CA1 neurons. Pre-synaptically Li+ enhances BDNF release which enhances LTP and post-synaptically Li+ prolongs the opening of AMPA receptors

Question 20

Why is the HPA axis over-stimulated in stress?

Answer 20

Under normal conditions, the hippocampus exerts an inhibitory effects on the hypothalamus, but chronically elevated glucocorticoids and severe traumatic stress can cause hippocampal atrophy. Therefore this allows excessive hypothalamic activation of the HPA axis

Question 21

What is the genetic basis of depression?

Answer 21

We know that there is a genetic link, but we don’t know exactly what it is.

Question 22

What are the treatments for depression?

Answer 22

1. MAOI
2. SSRIs
3. Psychotherapy
4. Ketamine

Question 23

How does ketamine work to treat depression?

Answer 23

Increases Glu in cortex by blocking NMDA receptors on interneurons so decreasing GABA

Question 24

Why are anti-seizure meds prescribed to patients with bipolar depression?

Answer 24

Bipolar is like epilepsy in that over time it results in increased frequency and increased severity of episodes. Drugs that increase GABA prevent these gradual events in the CNS by increasing inhibition overall.

Question 25

What pathway does Li+ work on?

Answer 25

Lithium may act on GSK3 (synthase kinase 3 that is part of Wnt signaling pathway)