Neurobiology of Depression - Craviso Flashcards
What are the areas of the brain that are involved in depression?
Hypothalamus Hippocampus Cingulate gyrus Amygdala Prefrontal Cortex Ventral Striatum
What type of scan shows activity dependent changes in blood flow, metabolism or bch activity?
PET
what type of scan shows detailed spatial images of the brain?
MRI
What happens to gray matter volume in the brain in depression?
decreased in all areas, except maybe the amygdala
What happens in cell counts and cell markers in depression
they all go down
t/F: there are a reduced number of synapses and glial cells in depression and reduced neuronal size
true
does blood flow increase or decrease in depression?
INCREASED to the mediodorsal nucleus of the thalamus, orbital and medial prefrontal cortex and to the amygdala
Increased metabolism in what area of the brain is associated with depression severity?
subgenual area of the anterior cingulate cortex
T/F: metabolism in the anterior cingulate cortex decreases with Rx treatment resulting in decreased depression
true
Responders to antidepressant therapy have increased metabolism in what area of the brain?
rostral anterior cingulate cortex
Reserpine inhibits what part of neurotransmission that leads to depression?
inhibits vesicular storage of norepi, dopa, and serotonin, results in depletion
Iproniazid inhibits monamine oxidase resulting in…
elevated mood; basis for the monoamine theory of depression
The monoamine theory of depression involves what two chemical systems?
serotonergic and noradrenergic
can involve dopamine
What are the two nuclei involved in the serotonergic system?
Rostral raphe nuclei
Caudal raphe nuclei
What are the two nuclei involved in the noradrenergic system?
lateral tegmental NA cell system
locus ceruleus
Antidepressant effects are likely due to adaptive changes in the CNS that happen (immediately/over time)
over time
What are the long term enhancement of monoamine transmission?
- desensitization of autoreceptors which then increases monoamine release
- increased activity of post synaptic monoamine receptors
Besides changes in serotonin levels, what changes do antidepressants have on synaptogenesis
slow increase in nerve growth factor expression (BDNF)
BDNF needed for neural plasticity, resilience, and nuerogenesis; aka changes in synaptogenesis
What does the neurotrophic hypothesis state?
- depression is assc’d with loss of nuerotrophic support
2. antidepressant therapy increases neurogenesis and synaptic connectivity
in which cortical area do antidepressants increase synaptic connectivity?
hippocampus
What is the effect of chronic high cortisol on the hippocampus?
atrophy of nuerons
death of neurons with prolonged stress leads to damage of hippocampus
decrease in BDNF
What vet tranquilizer/party drug is an NMDA glutamate receptor agonsit that can alleviate depression by stimulating synaptogenesis?
ketamine
what were the effects on depression of a single dose of ketamine?
a single dose of ketamine delivered via intravenous infusion alleviated depressive symptoms within hours
suicide ideation was decreased
found to be effective for patients who failed to respond to two or more conventional antidepressants (refractory depression)
also effective for bipolar disorder
effects lasted for several days to a week
Ketmaine binds to the NMDA receptor (on the terminal surface/inside the channel)
inside the channel
