Neurologic Basis Of Motor Speech - Cns

Front 1

Within the UMN system, what tracts of the Direct Access Pathway are related to speech?

Back 1

1-Corticobulbar Tracts: fibers with connections to brainstem nuclei of CN's V, VII, IX, X, XI, XII
2-Corticospinal Tracts: fibers with connections to spinal nerves for respiratory muscles

*bulbar = midbrain

Front 2

What is included within the Control Circuit system?

Back 2

1-Cerebellum
2-Basal ganglia

Front 3

What are the cortical components of the Direct Activation Pathway (DAP)?

Back 3

1-Primary motor cortex (aka postcentral gyrus, motor strip)
2-Supplementary motor area
3-Primary sensory motor cortex (aka, postcentral gyrus, somatosensory strip)

Front 4

From what nuclei does the primary motor cortex receive impulses from?

Back 4

1-Basal ganglia
2-Cerebellum
3-Thalamus

Front 5

What is the significance of the corona radiata?

Back 5

Nerve fibers converge here to form the internal capsule: contains all afferent and efferent fibers that project to and from the cortex

* lesions can cause widespread motor deficits

Front 6

UMN axons travel down to the level of which brainstem structure?;

What is the point of decussation called?

Back 6

1-medulla
2-medullary pyramids

Front 7

In the corticobulbar tract, describe the points of synapse of axons with the various cranial nerves within the brainstem

Back 7

V-trigeminal: PONS
VII-facial: PONS
X-vagus; MEDULLA
XI-accessory; MEDULLA
XII-hypoglossal; MEDULLA

Front 8

Describe the descention of axons within the corticospinal tract

Back 8

1-descend from cortex
2-through the internal capsule
3-to the brainstem
4-into the spinal cord

Front 9

Describe the effects of UMN unilateral lesions

Back 9

1-mild weakness on opposite side of body
2-minor effects to CN V, IX, X, XI due to bilateral innervation
3-Contralateral lower facial weakness after UUMN lesion
4-Dysarthria: weakness & loss of skilled movement

Front 10

Describe the effects of bilateral UMN lesions in the direct activation pathway

Back 10

1-loss of skilled movement
2-spastic muscle tone

Front 11

Describe the effects of lesions in the indirect activation pathway

Back 11

1-General: musle tone=spasticity; relexes=hyperreflexia
2-Above midbrain & red nucleus: increased extensor tone in legs & flexor tone in arms=decorticate posturing
3-Lesions at midbrain, below red nucleus: excitation of all extensor muscles=decerebrate posturing
3-Below medulla; loss of descending input=flaccidity in muscles innervated by spinal nerves
4-Brainstem lesions of the reticular formation=death

Front 12

Name the two control circuits of the CNS and their functions.

Back 12

1-basal ganglia (nerve knots)
2-cerebellum (little brain)

* Integrate & control diverse activities of many structures & pathways for motor performance

* Contribute to programming of movements
* Do not have direct contact with LMN's

Front 13

What are the functions of the basal ganglia?

Back 13

1-Regulating muscle tone
2-Maintaining normal posture
3-Static muscle contraction for voluntary, skilled movements
4-Regulate amplitude, velocity, and possibly, initiation of movement
5-movement selection & motor learning

Front 14

What are the effects of damage to the basal ganglia?

Back 14

1-Hypokinesia: deficiency of dopamine resulting in increased tone, rigidity, hypokinetic dysarthria

2-Hyperkinesia: excessive activiy in dopaminergic nerve fibers; reduces circuit's damping effect on cortical discharges

Front 15

What is the role of the cerebellum?

Back 15

1-Maintains equilibrium
2-Coordinates muscle action in: a) stereotyped movement (gait); b) non-stereotyped movement (reaching)
3-contributes to synergy of muscle action (muscles acting as a group)
4-ensuring muscles contract at right time
5-Corrects for over/under shooting
6-In speech, allows smooth flow of movement from one articulatory position to next

Front 16

What are effects of lesion to the cerebellum?

Back 16

1-Ataxic dysarthria - person may sound inebriated
2-Difficulty regulating movement; not paralysis
3-Discoordinated gate
4-Hypotonia - low muscle tone