Higgins Chapter 21 Review

Question 1

What are the three main arguments against the monoamine hypothesis as the only cause of depression?

Answer 1

• Medications take 6 to 10 weeks to reach full effectiveness
• Studies have failed to find consistent deficiencies in neurotransmitter levels
• Genome-wide association studies have not identified monoamine genes as culprits

Question 2

What is the relationship between the frontal cortex and symptoms of depression?

Answer 2

Dysfunctional communication between the frontal cortex and subcortical regions

Question 3

What imaging technique studies the synchronicity of different brain regions?

Answer 3

Functional connectivity

Question 4

What is the default mode network?

Answer 4

A network that becomes active during rest or daydreaming

Question 5

What is the effect of chronic stress on the hypothalamic–pituitary–adrenal (HPA) axis in depression?

Answer 5

Inability to turn down the HPA axis leading to excessive cortisol in the body which can overtime shrink the hippocampus.

Question 6

What is the outcome of the dexamethasone suppression test in depressed patients?

Answer 6

They fail to suppress cortisol levels

Question 7

What does increased cortisol from the adrenal gland cause in depression?

Answer 7

Hippocampal damage

Question 8

What role does the nucleus accumbens (NAc) play in reward dysfunction related to depression?

Answer 8

Mediates the drive for rewards

Question 9

Fill in the blank: Depression appears to result in the breakdown of the normal relationship between the _______ and the HPA axis.

Answer 9

hippocampus

Question 10

What is neurogenesis?

Answer 10

The process by which undeveloped stem cells in the brain migrate and mature into neurons or glial cells.

Question 11

What is the role of Brain-Derived Neurotrophic Factor (BDNF)?

Answer 11

Regulates the differentiation and survival of neurons.

Question 12

What structural changes are observed in the brains of depressed patients?

Answer 12

Subtle volumetric loss, including smaller hippocampus, PFC, cingulate gyrus, and cerebellum.

Question 13

What is one possible explanation for volume loss in depression?

Answer 13

HPA axis activation being neurotoxic to the brain.

Question 14

What is a key factor linked to shrinkage of the brain in depression?

Answer 14

Failure of neurogenesis and growth factor proteins like BDNF.

Question 15

What happens to BDNF levels in suicide subjects compared to controls?

Answer 15

Marked decrease in BDNF in the PFC and hippocampus.

Question 16

Which interventions have been shown to increase BDNF in rats?

Answer 16

• Antidepressants
• Lithium
• Stimulation treatments (ECT, TMS, VNS)
• Estrogen
• Exercise

Question 17

How do antidepressants affect BDNF levels in humans?

Answer 17

Increase serum BDNF levels significantly after treatment.

Question 18

What is the relationship between BDNF and neurogenesis?

Answer 18

Increased BDNF leads to increased neurogenesis.

Question 19

What effect does chronic stress have on BDNF mRNA in animal models?

Answer 19

Greatly reduces BDNF mRNA levels.

Question 20

What does excessive methylation of histones do to DNA access?

Answer 20

Limits access to the DNA, affecting gene expression.

Question 21

What is the proposed mechanism of depression according to recent studies?

Answer 21

Stress and genetic vulnerability decrease growth factor proteins due to DNA clogging.

Question 22

What unexpected finding has been observed in postmortem studies of depressed patients?

Answer 22

Reduced number and density of glial cells in the PFC.

Question 23

What is the rapid effect of ketamine in treating depression?

Answer 23

Can induce a robust antidepressant response within 2 hours.

Question 24

What receptor does ketamine block?

Answer 24

N-methyl-d-aspartate (NMDA) receptor.

Question 25

What is Deep Brain Stimulation (DBS) compared to?

Answer 25

A cardiac pacemaker for the brain.

Question 26

What is a major challenge in using DBS for treating depression?

Answer 26

Lack of understanding of the pathology of depression.

Question 27

What factors contribute to the development of depression according to the general consensus?

Answer 27

Interaction of dubious genes and difficult environmental events

Question 28

What gene did Avshalom Caspi's 2003 study focus on regarding depression?

Answer 28

Serotonin transporter gene

Question 29

What are the two versions of the serotonin transporter gene?

Answer 29

Short allele and long allele

Question 30

Individuals with which allele are predisposed to develop major depression when facing stressful events?

Answer 30

Short allele

Question 31

What did a meta-analysis six years after Caspi's study conclude about the serotonin transporter genotype?

Answer 31

No evidence of association with elevated risk of depression

Question 32

What is a distinctive feature of bipolar disorder?

Answer 32

Episodes of mania

Question 33

What has been a challenge in understanding the neuroscience of bipolar disorder?

Answer 33

Distinguishing differences from unipolar depression and healthy controls

Question 34

What imaging technique has shown disrupted functional connectivity in manic patients?

Answer 34

fMRI

Question 35

In manic patients, which two brain regions showed altered connectivity?

Answer 35

Amygdala and anterior cingulate cortex

Question 36

What has been found regarding gray matter volume in bipolar patients after lithium treatment?

Answer 36

Significant increases in total gray matter volume

Question 37

What do studies suggest about the relationship between the PFC and subcortical regions in bipolar disorder?

Answer 37

Abnormal interactions may be involved