Lecture 12: Basal Nuclei Control of Motor Function

Question 1

where do basal nuclei receive most of their input from

Answer 1

the cerebral cortex and return most of their output to the cerebral cortex

Question 2

list the paired nuclei that are in the basal nuclei

Answer 2

striatum
globus pallidus
substantia nigra
sub thalamic nucleus

Question 3

what are the two major basal nuclei circuits

Answer 3

putamen circuit (direct)
caudate nucleus circuit (indirect)

Question 4

lesions in the globus pallidus result in…

Answer 4

the inability to maintain postural support

or in continuous writhing movements

Question 5

lesions in the sub thalamic nuclei result in…

Answer 5

the release of inhibition on the contralateral side

or sudden flailing movements of an entire limb

Question 6

lesions in the striatum result in…

Answer 6

the release of inhibition or flicking movements in hands, face, or elsewhere
occurs in huntington’s patients

Question 7

lesions in the substantia nigra result in…

Answer 7

rigidity, akinesia, and tremors

occurs in parkinson’s patients

Question 8

define athetosis

Answer 8

Continuous spontaneous writing movements of a hand, arm, neck or face
Results from lesions in the globus pallidus

Question 9

define hemiballismus

Answer 9

Sudden, flailing movements of an entire limb

Results from lesions in the subthalamic nuclei

Question 10

define chorea

Answer 10

Flicking movements in hands, face or elsewhere

Results from lesions in the striatum

Question 11

define parkinson’s

Answer 11

Results from widespread destruction of pars compacta of substantia nigra that sends dopaminergic fibers to caudate nucleus and putamen
Rigidity of much of body musculature
Involuntary tremors of involved areas even at rest at a fixed rate
Serious difficulty in initiating movement
Postural instability
Dysphagia, speech disorders, gait disturbances, fatigue

Question 12

define huntington’s

Answer 12

Abnormal movements probably caused by loss of most cell bodies of GABA secreting neurons of caudate nucleus ad putamen and of Ach neurons in other parts of the brain
Flicking movements of individual muscles
Progressive severe distortional movements of entire body
Severe dementia
Motor dysfunctions

Question 13

What is agnosia? With what lesion is it associated?

Answer 13

Lesions of the posterior parietal cortex produce an inability to perceive objects through normally functioning sensory mechanisms

Question 14

What are the most important functions of the basal nuclei (ganglia)?

Answer 14

Plan and execute motor command in concert with the cerebral cortex; help cerebral cortex execute subconscious but learned pattern
Help plan multiple parallel sequential patterns
Control complex patterns of motor activity