Neuro III Flashcards
limbic system functions
Famous 5 F's Feeding Fleeing Fighting Feeling (emotion) Fucking *long-term memory + olfaction + behavior modulation + ANS function.
Structures of limbic system…
hippocampus + amygdala + fornix + mammillary bodies + cingulate gyrus
mesocortical symptoms
1) decreased activity leads to negative symptoms (flat affect, limited speech).
antipsychotic drugs and mesocortical pathway
Limited affect
Mesolimbic pathway symptoms…
Increased activity leads to positive symptoms (delusions, hallucinations)
Primary target of antipsychotic drugs?
Mesolimbic pathway
nigrostriatal pathway symptoms
Decreased activity leads to extrapyramidal symptoms (dystonia, akathisia, parkinsonism, tardive dyskinesia)
Major dopaminergic pathway in brain?
Nigrostriatal.
tuberoinfundibular pathway
Decreased activity leads to increased prolactin leading to decreased libido/sex dysfunction/galactorrhea/gynecomastia.
Input to cerebellum
1) contralateral cortex via middle cerebellar peduncle.
2) Ipsilateral proprioceptive information via inferior cerebellar peduncle from spinal cord.
Cerebellar output
1) Contralateral cortex to modulate movement.
2) Deep nuclei
Lateral –> medial cerebellar nuclei
Don’t Eat Greasy Foods
Dentate, emboliform, globose, fastigial
Output nerves of cerebellum involved in modulation of movement…
Purkinje cells –> deep nuclei of cerebellum –> contralateral cortex via superior cerebellar peduncle.
Affect of lateral lesion to cerebellum?
Impaired voluntary movement of extremities.
How do you tell side of cerebellar lesion?
Propensity to fall toward injured (ipsilateral) side.
Medial structures of cerebellum
Vermal cortex, fastigial nuclei.
What does damage to medial cerebellar structures cause?
1) truncal ataxia + nystagmus + head tilting.
2) generally result in bilateral motor deficits affecting axial and proximal limb musculature.
What does damage to flocculonodular lobe cause?
1) truncal ataxia + nystagmus + head tilting.
2) generally result in bilateral motor deficits affecting axial and proximal limb musculature.
bruxism
excessive teeth grinding and jaw clenching
Basal ganglia functions
1) voluntary movement
2) postural adjustments
How does basal ganglia modulate movement?
negative feedback to cortex
striatum components
putamen + caudate
putamen functions
motor
caudate functiosns
cognitive
Lentiform components
putamen + globus pallidus
Direct pathway receptor
D1 (d1rect pathway)
Indirect pathway receptor
D2
direct vs. indirect pathway function in basal ganglia
Direct is stimulatory.
Indirect inhibitory.
Excitatory/direct pathway
Cortical inputs stimulate the striatum, stimulating the release of GABA, which inhibits GABA release from the GPi, disinhibiting the thalamus via the GPi (increasing motion).
Inhibitory pathway
Cortical inputs stimulate the striatum, releasing GABA that disinhibits STN via GPe inhibition, and STN stimulates GPi to inhibit the thalamus (decreasing motion)
Dopamine affects
Binds to D1 –> stimulating excitatory pathways.
**Binding to D2 inhibits inhibitory pathway, leading to increased motion.
Athetosis due to lesion in…
basal ganglia
Chorea due to lesion in…
basal ganglia
Area commonly damaged in HD…
basal ganglia
What is dystonia?
Sustained, involuntary muscle contractions.
Examples of dystonia?
1) writer’s cramp
2) blepharospasm
ET treatment
1) nonselective beta-blockers (propranolol)
2) primidone
what is hemiballismus?
Sudden wild flailing of 1 arm +/- ipsilateral leg
hemiballismus due to damage to…
CONTRALATERAL sub thalamic nucleus
When is hemiballismus commonly seen?
lacunar strokes
intention tremor due to..
cerebellar dysfunction
What is myoclonus?
Sudden, brief, uncontrolled muscle contraction.
Examples of myoclonus?
1) jerks
2) hiccups
When does myoclonus often occur?
Metabolic abnormalities such as renal or liver failure.
What is alpha-synuclein?
Intracellular eosinophilic inclusions
How does neuronal death occur in HD?
via NMDA-R binding and glutamate excitotoxicity.
HD presentation on imaging
Atrophy of caudate and putamen with hydrocephalus ex vacuo.
Location of limbic association area…
FA 462
Location of sylvian fissure…
FA 462
Location of somatosensory association cortex…
FA 462
location of primary auditory cortex…
FA 462
Location of frontal eye field…
FA 462
Aphasia vs dysarthria
Aphasia – higher-order language deficit. Can refer to speaking, understanding, reading, or writing
Dysarthria – motor inability stop speak (movement deficit)
