Motor Control week 5 Flashcards
What is the main track linked to the motor system and the two parts of that track?
The Pyramidal corticospinal track
Lateral track - controls the hands fingers feet , distant parts of the body
Medial track - originates from the brain and is both contralateral and ipsilateral when it gets to the medulla and cerebellum, controls the trunk, balance turning
WHat does the extrapyramidal tract do?
- Responsilble for executing movements outside of cortical control such as reflexes , spontaneous actions
Such as the tectospinal tract which comes form the superior colliculus (linked to when we hear a noise randomly and we instantly turn our eyes towards it)
how are muscles activated ?
- Activated by motor neurons
- Agonist (tensing ) and antagonist(relaxing)
- Composed by elastic fibres that adjust length and tension
- two types of neurons arr alpha and gamma
what brain structures involved, three parts of the cerebellum
- Vestibulocerbellum - balance and postural stability
Spinocerebellum - Smooth control of movement
Cerebrocerebellum - regulation of highly skilled movement, complex spatial and temporal sequences , links to learning of skilled movement
parts of the basil ganglia and function
- for motor contoles, emotions executive funcrions and behavoiour
- Putamen
- Gloval pallidus
SUbthalamic nuclues - Substantia nigra
Near the cortex and also the cerebellum , helps with planning for movement , helps modulate movmeent but does not cause it
Loops the information , seen as the gatekeeper of action
what are the two pathways with the basal ganglia
- Direct : initiates movement
- Indirect : terminates movement
Primaty motor cortex , talkj about it
- sends signal yo muscle to move
- one to one mapping is innacuate and is more linked, many neurons are related to different muscles rathing than single localisation
Secondary motor area what are they linked to
- Planning motor actions
Increased activity before we see the action take place
1) SMA supplementary motor area ; planning of complex movement , more linked to internally guided actions , such as remebering the sequence of things
2) Premotor cortex - send commands to the primary motor cortex , can easily see this through EEGs as we see when it is active, visually guided actions such as following a yellow light
What do the anterior cingulate cortex and the right inferior frontal corte do?
- ACC - evluate reward of doing a certain actions, do we engage more or less
RIFC - inhibition of motor reponse
role of Parietal cortex
- Intention to move
Performance of complex well learned actions - Integration of sensory info and motor commands
What is the key symptoms of Parkinson’s
Akinesia: lack of movement
- Problems initiating movement
- Reduced amplitude of movements
Bradykinesia: slowness of movement
- Rigidity of limbs- Stooped posture
- Tremor
- “Parkinsonian mask”
where is there a lack of activity in the brain with Parkinsons
- imbalance between the direct and the indirect pathway .
Lack of activity in direct pathway, and over-activity of indirect pathway
Uneven pattern of dopamine loss in the striatum
Loss of dopamine was greater in the posterior putamen than in the anterior putamen and caudate nucleus
What are the main treatments for Parkinsons disease?
- Deep brain stimulation
Stimulation of the STN reduces motor symptoms - L-dopa; precursor that can cross the blood brain barrier
Exercise therapy
- Aerobic exercise
What is apraxia
Apraxia is a condition where patients are unable to execute an action, hey are defined as an inability to perform skilled, sequential, purposeful movement that cannot be accounted for by disruptions in more basic motor processes such as muscle weakness, abnormal posture or tone, or movement disorders.
this is split into
- ideational apraxia - the inability to form the idea of a movement
Ideomotor apraxia - there is an idea of the movement but there is no connection between the idea of the movement and the actual execution of that action
