motor disorders

Question 1

symptoms of motor cortex damage

Answer 1

• poor coordination
• weakness of voluntary movement
• upper motor neuron syndrome

Question 2

cerebral palsy

Answer 2

• result of damage to motor cortex
• often pre/peri-natally (50%-premature birth)
• stiffness/weakness of muscles
• poor coordination
• affects upper motor neurons
• 2/1000 births

Question 3

stroke

Answer 3

• interruption of blood supply that supplied the motor cortex
• upper motor neurons affected

Question 4

agency of action

Answer 4

=knowing it was you that did something in the world

• violations of AOA–>when you expect something to happen and it doesn’t–>perceptual shock
• connections between frontal areas (develop motor plans for voluntary action) and parietal (association/sensory processing) areas that monitor outcomes play key part

Question 5

basal ganglia

Answer 5

-group of nuclei lying deep in cerebral hemispheres
-dysfunction–>many disorders
-resolves competition between different motives - selection device
-receives excitatory input from many areas of cortex
-output goes back to cortex via thalamus
-usually inhibitory output (GABA)
5 nuclei: substantia nigra, caudate + putamen, globus pallidus, subthalamic nucleus

Question 6

the selection problem

Answer 6

• can’t do more than one thing at once so how is competition resolved?
• at rest: globus pallidus tonically active + lots of inhibition sent to thalamus that inhibits motor cortex, tuning down loop
• when action needed: bursts of excitation (dopamine) in striatum, globus pallidus isn’t inhibited for brief moments, thalamus excitable, increased excitation in motor cortex

Question 7

parkinson’s disease

Answer 7

3/1000 people
~50% more males
-excitatory input from cortex and dopaminergic input from substantia nigra is gone so can’t excite striatum - stuck in inhibition mode
-dopaminergic cells die
-monogenic PD: due to mutations of several genes

Question 8

treatment of parkinson’s disease

Answer 8

• increase level of dopamine with drugs
• deep brain stimulation: reduces activity in globus pallidus–>excitation flow through system. basal ganglia more sensitive to tiny signals

Question 9

the cerebellum

Answer 9

• knows what current motor command is + position of body and projects to motor cortex
• contains half total no. of CNS neurons
• projects most of upper motor neurons
• damage–>impaired movement (ataxia)
• voluntary movement loses fluidity –> mechanical

Question 10

ataxia

Answer 10

• damage to cerebellum
• 2 types: disturbances of posture/gait, no movement
• can appear like drunkeness

Question 11

upper motor neuron disease

Answer 11

• damage to cerebellum

- indicator is toes spreading wrong way instead of curling when foot stroked

Question 12

motor neuron disease

Answer 12

• motor neuron degeneration and muscle wasting due to non-stim of muscles
• ALS is a form of it
• stephen hawking
• 5,000 people in UK
• 2-5 years to live
• altered cognitive function, ability to communicate and affective changes
• complications due to impaired respiratory is often cause of death

Question 13

motor neuron disease treatment

Answer 13

• identify biomarkers (early diagnosis)
• identify risk factors
• novel neuroprotective drugs
• gene therapies
• drug to cure, slow progression
• clinical and technological interventions