#8.4 Basal Ganglia's Pathways + Parkinson's & Huntington's Disease

striatum

part of basal ganglia that is made up of caudate nucleus and putamen

direct

PATHWAYS:

striatium inhibits globus pallidus, which inhibits the thalamus

thalamus is an inhibitor, but since its inihibitted = go pathway

direct

PATHWAYS:

Increases activation of selected movement

direct

PATHWAYS:

Initiates and facilitates movement you want to do

direct

PATHWAYS:

Removes the "break" on the motor cortex - movement starts

indirect

PATHWAYS:

stop/control pathway

indirect

PATHWAYS:

Inhibits competing unwanted movements

indirect

PATHWAYS:

Prevents unwanted or competing movements

indirect

PATHWAYS:

Put more "breaks" on unnecessary muscle activation

direct

PATHWAYS:

damaged in parkinson's disease

indirect

PATHWAYS:

damage in huntington's disease

parkinson's disease

Gradual progressive death of neurons especially in substantia nigra (dopamine)

parkinson's disease

less dopamine = less excitation of cerebral cortex

parkinson's disease

Onset: after age 50, gradual progression

parkinson's disease

symptoms include bradykinesia, muscle rigidity, resting tremor, poor posture and balance, masked face, mild cognitive impairment, depression

bradykinesia

slowness of movement

resting tremor

shaking hands at rest

masked face

Reduced facial expression

parkinson's disease

possibly caused by genetics, exposure to toxins (MPTP), or lifestyle

parkinson's disease

could be treated by L-Dopa treatment, drugs, electrical stimulation (globus pallidus), neutrophins, & cell transplants

neutrophins

Promotes growth of remaining neurons

huntington's disease

Severe neurological and hereditary genetic disorder striking 1 in 10,000

huntington's disease

causes progressive death of neurons especially in the striatum (caudate + putamen) of the basal ganglia

huntington's disease

Trouble inhibiting unnecessary movements → excessive motion

huntington's disease

Symptoms appear in ages 30-50

huntington's disease

symptoms include chorea, coordination loss, difficulty speaking & swallowing, major cognitive decline, irritability, impulsivity, depression, progresses to dementia

huntington's disease

genetics: autosomal dominant (50% chance if parent has it)

huntington's disease

no cure, only symptom management = medications reduce excess movement