Neuro 9 - Motor control

planning. initiating, modifying and refining movement; neuromuscular junctions; motor units; reflex and voluntary responses

parts of brain involved in planning movement

prefrontal cortex and premotor cortex

parts of brain involved in initiating movement

primary motor cortex

planning movement

determining desired outcome and how to achieve

initiating movement

concentric, eccentric and isometric contraction of muscles

refining movement

choosing correct neurons and altering their sensitivity (enhancing activity) and inhibiting wrong neurons.

part of brain involved in refining movement

basal nuclei

part of brain involved in modifying/storing movement

cerebellum

storing/modifying movement — coordination

stores motor programs
compares real movement to planned movement
modifies ongoing activity through organisation of muscle contractions

Neuromuscular junction synapse

large

neuron-neuron synapse

small

one muscle fibre receives input from

one pre-synaptic neuron

one postsynaptic neuron recieves input from

multiple pre-synaptic neurons

what is a motor unit

a single lower motor neuron and all the muscle fibres it is connected to

small motor units

less power, more precision

large motor units

more power, less precision

neurotransmitter(s) used in NMJ and type of resultant local potentials

only Ach — therefore only excitatory potentials

which junction does NOT require summation and why?

NMJ, because there are no inhibitory potentials — therefore one pre-synaptic AP likely to bring fibre to threshold

function of voluntary response

enables interaction with environment

function of reflex response

protective: prevents injury

reflex response pathway

shorter — sensory receptors to spinal cord to muscle

voluntary pathway

longer — in through sensory receptors up to brain out through motor neurons

reflex latency

shorter, more consistent

voluntary latency

longer, highly variable

which response (reflex/voluntary) is trainable

voluntary