PHY2011 Lecture Notes - Lecture 29: Pars Reticulata, Supplementary Motor Area, Midbrain
20 Jun 2018
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Week 11 L1 (T5BL3)-Generating, controlling, refining and learning
(Fine and complex movements)
Control of muscle is not control on muscle
oIt’s control of the α motor neurons that control muscle
oMuscle only receives one input – from the α motor neuron
What are the Upper Motor Neurons that control LMNs for Fine movements?
oMidbrain and Motor cortex (see table above)
oRed nucleus
Sends neurons down to control α motor neurons
Receives input from the motor cortex
- Indirect way for the motor cortex to control α MN
Controls few, large groups of muscles
oFrom the brainstem upwards everything crosses over and controls opposite side
oMotor cortex + surrounding areas (pre-motor cortex and somatosensory cortex etc)
Cortico-spinal tract (CST) and cortico-bulbar tract (CBT) are newer pathways
for fine movement control
Important for control of distal muscles (fingertips and toes)
Size of cortical layers related to role
- L4 (Input) big in somatosensory cortex, small in motor cortex
- L5 (Output) big in motor cortex, small in somatosensory cortex
Where is the plan for fine practised movements located and what triggers this plan?
oInitiation and coordination of muscles in space and time
oSupplementary motor area (SMA)
oProducing already-learned movements (not reflexes)
oPrefrontal cortex -executive part of the brain
Personality and decision making
Triggers SMA
oPosterior Parietal cortex
Sensory input -somatosensory and visual
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Document Summary
Week 11 l1 (t5bl3)-generating, controlling, refining and learning (fine and complex movements) Control of muscle is not control on muscle: it"s control of the motor neurons that control muscle, muscle only receives one input from the motor neuron. What are the upper motor neurons that control lmns for fine movements: midbrain and motor cortex (see table above, red nucleus. Sends neurons down to control motor neurons. Indirect way for the motor cortex to control mn. Controls few, large groups of muscles: from the brainstem upwards everything crosses over and controls opposite side, motor cortex + surrounding areas (pre-motor cortex and somatosensory cortex etc) Cortico-spinal tract (cst) and cortico-bulbar tract (cbt) are newer pathways for fine movement control. Important for control of distal muscles (fingertips and toes) L4 (input) big in somatosensory cortex, small in motor cortex. L5 (output) big in motor cortex, small in somatosensory cortex. Direct: cortex striatum globus pallidus internal (gpi) &
