Lecture 1 and 2 Flashcards
Where is the primary motor cortex located?
Precentral gyrus in the frontal lobe.
How is the primary motor cortex organized?
Somototopically
Explain somototopic organization - think homunculus.
The bottom of the frontal lobe sends signals to the head and neck, and the upper portion sends signals to the lower body. More frontal lobe real estate is dedicated to our lips, tongue, and hands.
Where is the somotosensory cortex located?
What is the function?
Postcentral gyrus
Primary receptor of general body sensations
Name the 4 subcortical structures.
1) Diencephalon
2) Basal Ganglia
3) Substantia Nigra
4) Subthalamic Nucleus
Subcortical Structures:
What 4 structures does the Diencephalon include?
1) Thalamus
2) Hypothalamus
3) Epithalamus
4) Subthalamus
Where is the cerebellum located?
Rear of the brain, below the cerebrum
With what is the cerebellum involved?
Coordination
Where is the brainstem located?
Between the subcortical structures and the spinal cord
What does the brainstem consist of?
Midbrain, pons, and medulla
Where do upper motor neurons originate and terminate?
They originate in the cortex and terminate/synapse on lower motor neurons in either the brainstem (corticobulbar tract) or spinal cord (corticospinal tract)
Where do lower motor neurons originate and terminate?
Originate in the brainstem or spinal cord and terminate on the muscles they innervate
Muscles of the limbs only receive what type of innervation?
Unilateral, contralateral
Most muscles of the head and neck receive what type of innervation?
Bilateral
1)There are two pathways that a nerve signal must travel to reach a muscle - what are they?
1) The first is the lower motor neuron pathway and the 2nd is the upper motor neuron
2)
What makes up the pyramidal system and for what is the pyramidal system responsible?
- Corticospinal and corticobulbar tracts
- Responsible for voluntary movement
Where does the corticospinal tract originate?
Where does it cross over?
Where does it terminate?
- Begins in the cerebral cortex at different levels of the spinal cord. (Most axons originate in the primary motor cortex.)
- decussates at the pyramids of the lower medulla
- Terminates in the spinal cord at the level of the individual spinal nerves.
Where does the corticobulbar tract originate?
Where does it cross over?
Where does it terminate?
- Begins in the cerebral cortex
- decussates at the level of the cranial nerve nuclei they innervate
- Terminates at the cranial nerve nuclei located at different levels of the brainstem
For what is the frontal lobe responsible?
Motor planning
What is motor planning?
What area is involved in motor planning?
- Formulating a plan by specifying motor goals. Not muscle specific.
- Supplementary motor areas
Do the control circuits synapse directly on the lower motor neurons?
No
Control circuits have what function?
Do they project to the LMN?
Integrate or help control diverse activities of the structures and pathways involved in motor performance.
No