PBL - Parkinson's Disease Flashcards
Describe declarative memory
Factual information
Life events
Available to the consciousness
Easily formed and forgotten
Describe non-declarative memory.
Procedural memory
Motor skills
Not available to the consciousness
Less easily formed and forgotten
Describe ballistic movements
Movement based on pre-programmed instructions
Rapid, but at the expense of accuracy
- can’t accommodate unexpected changes
Describe visual feedback movements.
Motor command continually updated according to sensory feedback (e.g. Visual)
Highly accurate - can be modified in progress
Slow
Out of ballistic and visual feedback movements, which is used more often in the body?
A mixture of both
What does stimulation of the primary motor cortex do?
Elicits muscle twitches/movements depending on the amount of stimulation
What is the somatotrophic map?
Certain areas of the motor cortex specifically control certain areas of the body
How is the somatotrophic map distorted?
Face, hands and digits receive larger representation in the primary motor cortex
- due to more through the required for fine control
If there is a stroke or heamatoma in or near the primary motor cortex, what (motor) effect will be had on the body?
Paralysis and loss of sensation on the side contralateral to the pathology
What sensory information is crucial for co-ordinated movements?
Proprioception - feedback from peripheral sensory reports on the positions and movements of limbs
Vision - eyes, visual system, visual cortex
Vestibular - feed back from organ of balance
What are the main non-cortical structures required for movement?
Basal ganglia
Cerebellum
What is the input and output from the basal ganglia?
Input - prefrontal motor cortex (intended movement)
Output - premotor area of the thalamus
What are the functions of the basal ganglia?
Initiation of movement - puts motor plan into action
Planing of complex voluntary movement
What is the input and output for the cerebellum?
Input - sensory cortex
Output - primary motor cortex (via the thalamus)
What are the functions of the cerebellum?
Co-ordination and smooth execution of movements
Motor learning
Error detection
What does damage to the cerebellum do?
Causes cerebellar ataxia - poor co-ordination
What are the lateral descending motor pathways?
Corticospinal and rubrospinal
- pyramidal neurons in primary motor cortex project to the spinal cord (corticospinal) and red nucleus (rubrospinal)
What are the functions of the lateral motor pathways?
Control of voluntary movements
- e.g. Fine control of the hand by distal muscles
What is the function of the vestibulospinal tract?
Balance and posture
What is the function of the reticulospinal tract?
Medial path facilitates voluntary movement and increased muscle tone
Lateral path inhibits voluntary movements and decreases muscle tone
What is the function of the tectospinal tract?
Co-ordinates movements in the head in relation of visual stimuli
What evidence is there for function of the supplementary motor cortex?
Imaging studies show your primary motor cortex, premotor cortex and supplementary motor cortex are involved involved in moving a finger.
However, only the SMA is involved in THINKING about moving the finger (but not actually moving it)
What are the symptoms of Parkinson’s disease?
Tremor Bradykinesia Shuffling gait Rigidity Progression to general cognitive decline
What are the two treatments for Parkinson’s?
Levodopa - and cabidopa to prevent peripheral breakdown
Deep brain stimulation
What is Huntington’s disease?
Suppression of activity in the basal ganglia
What are the symptoms of Huntington’s disease.
Choreas
Difficulty speaking and swallowing
General cognitive decline
How do intrinsic circuits of the spinal cord produce the rhythmic motorneuron activity which drives stepping?
Alternating activity in flexor and extensor muscles co-ordinated across two limbs
Two sets of pattern generating neurons project to flexor and extensor motorneuron pools respectively
Reciprocal inhibitory connections between the two sets of pattern generating neurons help to co-ordinate their activity
- alternating excitement of flexors and extensors
Motorneuron pools of each muscle form columns in the ventral horn, what are they called?
Motornuclei
What is the most important mechanism for grading motor force?
Recruitment of motor neurons
Describe the effect of action potential frequency in motor axons on muscle fibre contraction.
The more action potentials, the stronger the muscle contraction
No rest period means each action potential increases contraction form an already elevated level
