PHYS20008 Lecture Notes - Lecture 9: Microtubule, Skeletal Muscle, Vestibular System
21 Jun 2018
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Lecture 9: Motor control and nerve/muscle integration
There are 3 types of movements:
1) Reflex: An automatic response to a stimulus that does not receive or need conscious
thought; rapid, least complex type of movement
2) Voluntary: Movements that are mainly under conscious control; planned acts that
are executed with a lot more precision and, therefore, is also the most complex-
requiring higher brain centres to execute these.
3) Rhythmic: This is where initiation and termination is voluntary but the actual
movement is more ‘stereotypical’; happening reflexively and is of intermediate
complexity.
Voluntary movement:
Voluntary movements can be divided into 3 phases:
1) Planning
2) Initiation
3) Execution
Different parts of the brain are allocated to these 3 phases:
Basal nuclei: The area responsible for emotional processing, deciding specific
actions; how to execute the movements (PLANNING)
Cortical association areas: These areas process the idea, the ‘what’ (PLANNING)
Motor cortex: This sends the signal to the target area; for example, the legs if
walking (INITIATION)
Cerebellum: Responsible for the fine-tuning of movements, motor control, muscle
memory- stores learned muscle behaviour (EXECUTION)
Essentially, a movement is carried out like this:
Sensory input from receptors Spinal cord Cerebral cortex Cerebellum.
*Signals from the vestibular apparatus go directly to the cerebellum (Postural and spinal reflexes do
not require integration in the cortex)
*Output signals initiate movement without higher input
‘Receptors’ controlling movement (balance, reflexes etc.) should be sensitive to muscle
length and muscle force stimuli. Neuronal convergence and divergence, EPSPs and IPSPs,
EPPs (end plate potentials), action potentials, ionic fluxes, Golgi tendon organs and spindles
are most commonly involved processes/structures in controlling movement within the
neuronal circuits.
Convergence and divergence: Sending and receiving signals
Golgi tendons and spindles: Sensory receptors of the muscles
Synaptic reflexes:
Monosynaptic reflex: Has a single synapse between the afferent and efferent
neurons (reports directly to the alpha motor neuron)
Polysynaptic reflexes: Have 2 or more synapses (reports to afferent, to interneurons
(minimum of 1), then to the alpha motor efferent neuron)
For example, if the sensory afferent is excitatory and the interneuron is inhibitory, increased
activation of the receptor would make the muscle more likely to relax.
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Voluntary movements can be divided into 3 phases: planning. Different parts of the brain are allocated to these 3 phases: Basal nuclei: the area responsible for emotional processing, deciding specific actions; how to execute the movements (planning) Cortical association areas: these areas process the idea, the what" (planning) Motor cortex: this sends the signal to the target area; for example, the legs if walking (initiation) Cerebellum: responsible for the fine-tuning of movements, motor control, muscle memory- stores learned muscle behaviour (execution) Essentially, a movement is carried out like this: Sensory input from receptors spinal cord cerebral cortex cerebellum. *signals from the vestibular apparatus go directly to the cerebellum (postural and spinal reflexes do not require integration in the cortex) Receptors" controlling movement (balance, reflexes etc. ) should be sensitive to muscle length and muscle force stimuli. Epps (end plate potentials), action potentials, ionic fluxes, golgi tendon organs and spindles are most commonly involved processes/structures in controlling movement within the neuronal circuits.
