Session 2 Flashcards
investigating which areas are involved:
ØLesions inflicted on animals
Appetite, weight, forced swimming test, tail suspension test
ØBrain operations
ØImaging
ØRabies virus affects limbic cortex - personality changes
ØLesions to certain areas in humans
Amygdala lesions lead to loss of spontaneous aggression
areas implicated?
ØStriatum - basal ganglia
ØNeocortex - prefrontal cortex
ØLimbic system (motivation, emotion, memory)
Parts of the limbic system?
cingulate gryus (part of temporal lobe)
hippocampus - motivation, emotion, memory
amygdala - conditioning, emotional processing, input from sensory areas, and connected to areas the control autonomic function, motor function, & neuro-endocrine responses
hypothalamus
MRI & CT changes in depression?
white matter changes = poor response to treatment
may be decreased size of hippocampus - correlates with duration of illness
fMRI changes in depression?
fMRI measures difference between oxygen rich and oxygen poor blood flow - measures neuronal activity in brain
in depression: amygdala and cingulate gyrus signals are abnormal before CBT, normalised after
pre-treatment decreased reactivity in cingulate gyrus & increased in amygdala related to better post-treatment outcomes
SPET & PET changes?
gamma emitting isotopes connect to certain structure in the brain
can measure blood flow, brain activity, receptors
brain activity decreased during depression
Functions of the 3 prefrontal areas:
Ventro-medial prefrontal cortex (VMPFC) - pain, aggression, sexual function, eating
- Hyperactivity in VMPFC - enhanced sensitivity to pain, anxiety, depressive ruminations
Lateral orbital prefrontal cortex (LOPFC) - assesses risk, regulates affective states
Dorso lateral prefrontal cortex (DLPFR) - executive function & attention/concentration
- Hypo-activity - psychomotor retardation, apathy deficits in attention
- Disconnectivity between prefrontal areas and limbic system results in dysregulation of emotional control*
Cortisol/HPA changes?
cortisol high
dysregulation of HPA axis appears to be related to hippocampal atropy
Growth hormone changes?
blunted response to GHRF
thyroid hormone changes?
incipient hypothyroidism
TSH response to TRH blunted
thyroxine sometimes used in depression
role of dysruption of cytokines in depression?
over activity in depression, possibly caused by increase in sympathetic tone (caused by HPA axis overactivity and amygdala dysregulation)
disruption caused by cytokines can result in:
- fatigue
- loss of apetite
- loss of libido
- hypersensitivity to pain
- also disrupts other hormone systems e.g. blood sugar
- negative effects on neurotransmission and neuro-trophic factors
brain derivd neuro-trophic factor role and affect in depression?
role in cell maintenance and plasticity of the brain
dysregulation in depression and chronic stress
low levels in untreated patients - affects limbic system negatively
sleep pattern changes?
awake - REM - NREM
REM - psychological therapy
NREM - recovery of muscles
In depression, REM latency is reduced from 35 mins to 18 mins
early morning wakening also
