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What influences the hypothalamus?
- neural influences
- hormonal influences
What are the functions of the hypothalamus?
- ANS regulation from descending pathways
- hormone production
- endocrine regulation from pituitary gland
- circadian rythym regulation relays thru hypothalamus to visual systems then project back to pineal gland creating light/dark cycles
- limbic system variation
- other various things: temp regulation/feeding
What can disorders of the hypothalamus cause?
- temp regulation problems
- sleep disturbances
- genital hypoplasia
- effect optic/visual system
What does the limbic system control?
- emotional, behavioral type of center of the brain
- preservation of species (securing food, defense mechanisms, sexual behavior)
- affective behavior
Where is the limbic system located?
deep and close to the midline
What are different components of the limbic system?
- cingulate gyrus
- parahippocampal gyrus
- mamillary body
- anterior thalamic nucleus
- septal nucleus
- dorsomedial thalmic nuclei
What is the circuit of papez?
- describes structural standpoint connections in the limbic system
- starts in hippocampus --> through fornix to mammilary body --> to anterior thalamic nucleus --> to cingulate gyrus and back through cingulum to hippocampus again
Where is the amygdala located?
- deep to uncus
- rostral to hippocampal formation
- near tail of caudate
- rostral part of lateral ventricle inf. horn
What is the function of the amygdala?
- lip smacking
- autonomic responses
What did the Kluver-Bucy monkey study reveal?
- Kluver-Bucy syndrome
- placidity (mellow)
- visual agnosia (wouldn't be scared of snakes)
- oral tendencies
What can cause Kluver-Bucy syndrome?
- chronic alcohol abuse
- deep brain injuries
What are other names for thalamic pain syndrome?
- central pain syndrome
- Dejenne-Roussy syndrome
- posterior thalamic pain
- retrolenticular stroke
What can cause thalamic pain syndrome?
- direct injury to thalamus
- suprathalamic cortical lesion
- brainstem infarct
- primary or secondary tumors
What are signs/symptoms of thalamic pain syndrome?
- pain is continous and excrutitating after it starts
- allodynia: pain elicited by non-noxious stimlui (shaving, make up)
- hyperalgesia: exaggerated pain response to noxious stimuli
- dysthesia: abnormal pain sensations (dante-esque pain- dante's inferno)
What is central sensitization in thalamic pain syndrome?
- ectopic discharge: cells associated with pain create it at cortical and thalamic levels
- reorganization of mechanoreceptor input: DC/ML; receptors go to bad places of the thalamus
- inappropriate connections w/ nocioceptive pathways
- reduced nocioceptive threshold
- increased receptive field size causing mulitple neurons to dishcharge with a small stimulation on the skin so the receptive fields overlap
- loss of descending inhibitory control over pain pathways in the thalamus, so the ascending pathways go wild