Intro To Neuroanatomy - Lecture 1 Flashcards
Where are the upper motor neurones located?
Cerebral cortex
Motor areas
How do the cerebellum and basal ganglia act upon the cerebral cortex?
Indirectly via the thalamus(the only direct input to the cerebral cortex)
What is the hierarchy of motor control within the brain?
Motor cortex
Cerebellum
Basal ganglia
How does the motor cortex connect to the spinal cord? What occurs with injury of this area?
Motor cortex has direct link with spinal cord via the corticospinal tract (upper motor neurons)
Damage to this area causes spasticity/paralysis
What information does the cerebellum receive and from where?
Afferent information from the spinal cord (spinocerebellum) and also information from the cerebral cortex (cerebrocerebellum) also argument for info from brain stem (vestibulocerebellum)
What occurs with injury at the cerebellum?
Inaccurate / poorly timed movement can be observed (looks like person is drunk)
What occurs with damage to basal ganglia?
Can result in difficulty initiating/terminating movement e.g. Parkinson’s and Huntingtons
What does the gray and white matter of the spinal cord contain?
Gray matter contains all the cell bodies of the neurons(sensory, motor and interneurons)
White matter contains the axonal tracts
The motor neurons exhibit ‘somatotopy’, what does this mean?
The proximal and distal muscles are represented in the proximal and distal spinal cord.
Motor neurones for distal muscles (hand) lay in the dorsolateral part of the spinal gray
Motor neurones for more medial muscles lay at progressively more medial (the ventromedial cell group) parts of the spinal gray
Which side is the dorsal side of the spinal cord, and what is the dorsal side typically associated with?
Dorsal means the back side, and is concerned with the entering of sensory information.
Sensory info from muscles such as spindles or GTO enters via this dorsal route
What are the 2 lateral and 2 medial spinal tracts?
Lateral - corticospinal, rubrospinal
Medial -vestibulospinal, reticulospinal
What are the 4 key spinal descending tracts point of origin?
Corticospinal - originates in the motor cortex
Rubrospinal - originates in the red nucleus (midbrain)
Vestibulospinal - originates in the vestibular nuclei
Reticulospinal - orginates in the reticular formation (pontine+medullary)
Does the CS cord make direct or indirect connections to the motor neurons?
Both, indirect is via the brain stem pathways.
What is pyramidal decussation?
This is where the CS tract crosses over to the other side of the body. 90% of the tract crosses over (lateral CS tract), 8% is the ventral CS tract and 2% does not cross over
How does the number of direct connections to the spinal cord change In species?
Higher animals have more direct connections, which correlates with manual dexterity. However this reliance means humans are less able to cope with spinal damage