What are the functions of basal nuclei?
- execute motor commands with cerebral cortex
- plan multiple sequential patterns
- control patterns of motor activity
What paired nuclei help form the basal nuclei?
- striatum
- globus pallidus
- substantia nigra
- subthalamic nucleus
What is the principal role of basal nuclei?
- modulate thalamic output to motor cortex to plan and execute smooth movements
What are the major basal nuclei circuits?
- putamen
2. caudate nucleus circuit
What is the putamen circuit used for?
subconscious execution of learned pattern movement
Is the putamen circuit excitatory or inhibitory?
excitatory, cause increased motoractivity
What is the pathway of the putamen circuit?
- cerebral cortex
- putamen
- globus pallidus
- thalamic relay nuclei
- primary motor cortex
What are the actions of the D1 and D2 dopamine receptors?
D1: excitatory
D2: inhibitory
What will a lesion to the globus pallidus cause?
- athetosis
- continuous writhing of hand, arm, neck, face
What will a lesion to the subthalamic nuclei cause?
- hemiballismus
- sudden flailing of entire limb
What will a lesion to the striatum result in?
- chorea
- flicking of hand, face, neck
A lesion to the substantia nigra will cause what?
- rigidity, akinesia, and tremors known as Parkinson’s disease
What is the caudate circuit used for?
- cognitive planning of sequential and parallel movements
2. overall inhibitory
Where is dopamine most commonly found?
substantia nigra to caudate nucleus/putamen
Where is GABA generally found?
caudate nucleus/putamen to globus pallidus/substantia nigra
Where is Acetylcholine generally found?
cortex to caudate nucleus/putamen
What best describes symptoms of Parkinson’s Disease?
- rigidity of body muscles
- involuntary tremors during rest
- akinesia
- unstable posture
- dysphagia, gait disturbance, fatigue
What causes Parkinson’s Disease?
- destruciton of substantia nigra pars compacta
- -causes loss of inhibitory and excitatory input
How can Hutington’s disease best be described?
- 30-40y/o
- individual muscle flicking
- distorted movements of body
- dementia
- motor dysfunction
What is the most probably cause for the abnormal body movements?
- loss of GABE secreting neurons in caudate nucleus/putamen,
- loss of Ach neurons in other brain portions