neuro-biology of depression

Question 1

function of frontal lobe?

Answer 1

(planning + organisation)
primary motor cortex
supplementary motor cortex
executive functions 
broca's area (originates speech)
affect on behaviour in conjunction with the temporal lobe

Question 2

function of parietal lobe?

Answer 2

sensory cortex
Wernicke's area (understanding of language)
orientation
recognition
construction

Question 3

function of temporal lobe?

Answer 3

primary auditory cortex
music recognition
memory
emotion
behaviour

Question 4

function of occipital lobe?

Answer 4

primary and secondary visual cortex

Question 5

what are the areas of the limbic system?

Answer 5

cingulate gyrus
hippocampus
amygdala
hypothalamus
septum
olfactory bundle
dentate gyrus
anterior nucleus of the thalamus
mammillary bodies

Question 6

what are the main functions of the limbic systems?

Answer 6

emotion
motivation
memory

Question 7

function of the amygdala?

Answer 7

critical for conditioning and emotional processing
input from a range of sensory areas
connected to areas that control autonomic function, motor action, neuro-endocrine responses

Question 8

types of imaging done on the brain?

Answer 8

MRI
f MRI
SPECT
PET

Question 9

what do MRI and CT show in patients that are depressed?

Answer 9

white matter changes are related to depression
patients with white matter changes have relatively poor response to treatment
structures in the brain can be measured

Question 10

changes in the size of the hippocampus in depression?

Answer 10

hippocampus has major role in memory functions
in depressed patients, the hippocampal volume is consistently and significantly reduced
reduction in hippocampus correlated with duration of illness

Question 11

functional imaging used to measure relative activity of parts of brain?

Answer 11

fMRI
PET
SPECT

Question 12

describe fMRI

Answer 12

focuses on blood flow
measures the difference between oxygen rich and oxygen poor blood flow
therefore measures neuronal activity in brain areas and spinal cord

Question 13

fMRI in depression (pre and post treatment of amygdala and cingulate gyrus)

Answer 13

amygdala and cingulate gyrus signals are abnormal before CBT treatment and normalise after treatment
pre-treatment decreased reactivity in the cingulate gyrus and increased reactivity in the amygdala are related to better outcomes post treatment

Question 14

what is SPET?

Answer 14

single-photon emission tomography

Question 15

principles of PET and SPET?

Answer 15

gamma emitting radio-isotopes
the isotopes connect to certain structures in the brain
cameras to detect the emitting radiation
computer programmes to quantify
(PET shorter 1/2 life isotopes and more expensive)

Question 16

what can PET and SPET measure?

Answer 16

blood flow
brain activity
receptors

Question 17

mal-function of the prefontal areas in depression

Answer 17

enhanced sensitivity to pain, anxiety, depressive ruminations
psychomotor retardation, apathy and deficits in attention
disconnectivity between the prefrontal areas and the limbic system results in disregulation of emotional control

Question 18

cortisol / HPA axis in depression

Answer 18

cortisol levels found to be consistently high in depression

disregulation in the HPA axis appears to be related to hippocampal atrophy

Question 19

neuroendocrine changes in depression

Answer 19

cortisol
thyroid
(GH)

Question 20

function of cortisol

Answer 20

implicated in responses to stress
exogenous cortisol has an effect on mood
dexamethasone suppression test

Question 21

thyroid abnormality in depression

Answer 21

TSH response to TRH blunted

thyroxin sometimes used in depression

Question 22

cytokines and depression

Answer 22

evidence of over activity of cytokines in depression possibly caused by:
increase in sympathetic tone (caused by HPA axis overactivity and amygdala disregulation)

Question 23

disruption caused by cytokines can result in?

Answer 23

fatigue
loss of appetite
loss of libido
hypersensitivity to pain
also disrupts other hormone systems e.g. blood sugar control
negative effects on neurotransmission and neuro-trophic factors

Question 24

main substance of neuro-trophic factors?

Answer 24

brain derived neuro-trophic factor (BDNF)

Question 25

function of BDNF?

Answer 25

has a role in:

cell maintenance + plasticity in the brain

Question 26

BDNF and depressoin

Answer 26

disregulation of BDNF in chronic stress and depression
levels of BDNF lower in untreated patients
the low levels of BDNF affect structures e.g. limbic system negatively

Question 27

changes in sleep architecture (hypnogram) in depression

Answer 27

the REM latency (reduced in depression)
anti-depressants can restore normal sleep architecture
EMW