Neurobiology of mood disorders

Question 1

What is the evolutionary function of anger?

Answer 1

This is a response to competition to attempt to increase threat and overpower

Question 2

What are the 2 choices that all animals have during conflict?

Answer 2

• Try harder, increase threat, overpower
• Back off, retreat, submit

Question 3

What is the function of the defeat response?

Answer 3

If we lose a conflict, we need to have in-built mechanisms to inhibit further challenging behaviour and to signify that we are backing off to prevent harm and aggression towards us

Question 4

What are some changes that occur in the defeat response?

Answer 4

• Running away
• Down-grading expectations
• Signalling to others that we are no longer a threat

Question 5

What are some of the consequences to an individual of activation of the defeat response?

Answer 5

• Reductions in social confidence
• An inhibition of challenging and acquisitive behaviour

Question 6

What condition is possibly liked to higher levels of internal defeat?

Answer 6

Depression

Question 7

What are the 3 parts of the “triune brain”

Answer 7

Core - Reptilian brain
Middle - Paleomammalian brain
Cortex - Neomammalian brain

Question 8

Function of the reptilian (Core) brain?

Answer 8

Basic functions - Eating, moving

Question 9

Function of the paleo mammalian (Middle) brain?

Answer 9

Intermediate functioning

Question 10

Function of the neomammalian (Cortex) brain?

Answer 10

Advanced functioning such as imagination and invention

Question 11

What region of the brain is thought to represent the reptilian brain?

Answer 11

Limbic cortex

Question 12

Which parts of the triune brain are though to be involved in depression?

Answer 12

The psychological aspects of depression such as hopelessness and defeat may be routed in the neocortex brain, but the fundemental, biological aspects seem to be routed in deeper parts of the brain

Question 13

What are the 2 broad systems of the brain?

Answer 13

Appetitive/approach system (Usually +ve)

Aversive/defensive systems (Usually -ve)

Question 14

What is the function of the appetitive/approach systems?

Answer 14

Function is to mediate seeking and approach behaviours, including pleasure

Question 15

What is the function of the aversive/defensive system?

Answer 15

• Function is to promote survival in the event of threat
• This drives anxiety, fear and pain

Question 16

Components of the appetitive/approach systems?

Answer 16

• Ascending dopamine systems
• Ventral striatum (Reward)
• Dorsal striatum (Movement)
• Amygdala (Conditioning, learning)
• Anterior cingulate (Attention, conflict, response selection)
• Orbitofrontal cortex (Relative reward preference, rule learning)

Question 17

Components of the aversive/defensive systems?

Answer 17

• Ascending serotonin systems
• NA/CRF/Peptide transmitters
• Central nucleus of amygdala
• Hippocampus
• Ventroanterior and medial hypothalamus
• Periaqueductal grey

Question 18

How is serotonin expression affected in depression?

Answer 18

In depression, there are abnormalities of distribution of 5-HT1 and 5-HT2 receptors in the brain

There is usually a decrease of 5-HT2 receptors in certain parts of the brain (Especially the cortex) and an increase of 5-HT1 receptors in some parts and a decrease in others

Question 19

What are some brain regions that have been shown to be implicated in mood disorders?

Answer 19

• Orbital frontal cortex
• Ventromedial prefrontal cortex
• Dorsolateral prefrontal cortex
• Hippocampus
• Amygdala
• Anterior cingulate cortex

Question 20

What are some forms of functional imaging of the brain?

Answer 20

• fMRI (Functional)
• PET
• SPECT