Ch 5: Clinical Correlates pg 149-154

Question 1

what is dopamine’s effect on the basal ganglia direct motor pathway?

Answer 1

excites the direct pathway which excite UMNs in motor cortex

Question 2

what is dopamine’s effect on basal ganglia indirect motor pathway?

Answer 2

inhibits indirect pathway, reducing its suppression of motor cortex activity and direct basal ganglia pathway

Question 3

what is the cholinergic neuron’s effect on basal ganglia indirect motor pathway?

Answer 3

enhances effects of indirect pathway

*inhibits VA and VL thalamic nuclei to reduce activity of motor cortex and direct basal ganglia pathway

Question 4

dyskinesia and an involuntary tremor (rest tremor) associated with lesion where?

Answer 4

direct motor basal ganglia pathway

Question 5

Parkinson’s disease is caused by what?

Answer 5

degeneration of dopaminergic neurons in substantia nigra

–>inhibits direct motor basal ganglia pathway and suppresses motor cortex

Question 6

problems initiating movements, reduced velocity and amplitude of movements, pill-rolling tremor at rest in fingers, skeletal muscles in upper limbs with cogwheel/lead pipe rigidity (increased muscle tone), stooped posture, shuffling gait, expressionless face all are symptoms associated with…

Answer 6

Parkinson’s

Question 7

hyperkinetic disturbances, overactive motor cortex, and pronounced involuntary movements (chorea, athetosis, dystonia, tics, hemiballismus) are all associated with lesions/diseases where?

Answer 7

indirect pathway of basal ganglia

Question 8

what is chorea?

Answer 8

involuntary movements that are purposeless, quick jerks that may be superimposed by voluntary movements

Question 9

what diseases are associated with chorea?

Answer 9

Huntington’s (degeneration of indirect pathway GABA neurons and AEh heurons in striatum/head of caudate nucleus)

Sydenham’s (possible transient complication in children with rheumatic fever)

Question 10

what is athetosis?

Answer 10

slow writhing, involuntary movements that are most evident in fingers and hands

*frequently seen in Huntington’s patients

Question 11

what do blepharospasms, spasmodic torticollis, and writer’s cramp all have in common?

Answer 11

forms of dystonia

• blepharospasms- contractions of orbicularis oculi muscles–>eyes close
• spasmodic torticollis- head pulled toward shoulder
• writer’s cramp- contraction of arm and hand muscles on attempting to write

Question 12

what is dystonia?

Answer 12

slow, prolonged movements

Question 13

what is hemiballismus? and what is it caused by?

Answer 13

violent ballistic movements of a limb

contralateral lesion of subthalamic nuclei

ex. lacunar stroke of a thalamoperforating branch of a posterior cerebral artery

Question 14

facial and vocal tics that progress to jerking movements of the limbs; may have involuntary explosive, vulgar language … this is associated with what syndrome?

Answer 14

Tourette’s

Question 15

personality changes, dystonia, a “wing-beating” tremor, Kayser-Flesicher (thin, brown ring around outer cornea) is associated with what disease? what is it caused by?

Answer 15

Wilson’s disease

abnormality of copper metabolism–>accumulation of copper in liver

Question 16

what four direct pathways is the basal ganglia involved in?

Answer 16

motor, cognitive, oculomotor, limbic

Question 17

Huntington’s disease can affect the cognitive and limbic basal ganglia pathways and result in what symptoms?

Answer 17

changes in mood or character in form of irritability or impulsive behavior

*due to loss of GABA neurons in cognitive pathway

Question 18

changes in the activity of the mesolimbic and mesocortical dopamine projections in the cognitive and limbic pathways may be associated with what psychologic disease?

Answer 18

schizophrenia

Question 19

what symptoms characterize schizophrenia?

Answer 19

• positive symptoms: delusions, disordered thoughts with incoherence, loss of touch with reality, hallucinations
• overactive mesolimbic dopaminergic pathway
• negative symptoms: social withdrawal, lack of motivation, poor attention span, slowed speech, lack of emotional arousal
• decreased mesocortical dopaminergic pathway

Question 20

how do antipsychotic drugs treat schizophrenia?

Answer 20

antipsychotic drugs have affinity for D2 dopamine receptors–>decrease dopamine transmission and reduce overactive mesolimbic system and positive symptoms

Question 21

what is a potential side effect of antipsychotic drugs?

Answer 21

tardive dyskinesia- involuntary movements of the tongue and face and cogwheel rigidity

*similar to PD

Question 22

hyperactivity of GABA neurons in the head of the caudate nucleus may be associated with what disorder?

Answer 22

obsessive-cumpulsive disorder

Question 23

how do cocaine, amphetamine, morphine and nicotine affect dopamine?

Answer 23

enhance dopamine effect in mesolimbic projection to nucleus accubens

• cocaine, amphetamine, and morphine increase time dopamine remains in synapatic cleft
• nicotine enhances release of dopamine