Exam 1: Corticospinal and other descending pathways Flashcards
Identify the cortex or functional area represented by red line
![](https://s3.amazonaws.com/brainscape-prod/system/cm/176/859/857/q_image_thumb.png?1453350210)
Primary motor cortex
![](https://s3.amazonaws.com/brainscape-prod/system/cm/176/859/857/a_image_thumb.png?1453350491)
Identify the cortex or functional area represented by red line
![](https://s3.amazonaws.com/brainscape-prod/system/cm/176/860/292/q_image_thumb.png?1453350605)
Somatosensory cortex
![](https://s3.amazonaws.com/brainscape-prod/system/cm/176/860/292/a_image_thumb.png?1453350513)
Identify the cortex or functional area represented by red line
![](https://s3.amazonaws.com/brainscape-prod/system/cm/176/860/297/q_image_thumb.png?1453350623)
Premotor cortex
![](https://s3.amazonaws.com/brainscape-prod/system/cm/176/860/297/a_image_thumb.png?1453350526)
Identify the cortex or functional area represented by red line
![](https://s3.amazonaws.com/brainscape-prod/system/cm/176/860/370/q_image_thumb.png?1453350643)
Supplementary motor cortex
![](https://s3.amazonaws.com/brainscape-prod/system/cm/176/860/370/a_image_thumb.png?1453350536)
Identify the cortex or functional area represented by red line
![](https://s3.amazonaws.com/brainscape-prod/system/cm/176/860/373/q_image_thumb.png?1453350580)
posterior parietal cortex
![](https://s3.amazonaws.com/brainscape-prod/system/cm/176/860/373/a_image_thumb.png?1453350547)
Pathway - Cortex:
• ___-___ neuron system that starts in the cortex and ends at various level of the spinal cord on _____ _____ neurons
Pathway - Cortex:
• 2-3 neuron system that starts in the cortex and ends at various level of the spinal cord on lower motor neurons
Pathway - Cortex:
• Cell bodies of upper motor neurons are located in layer _____ if the cerebral cortex
Pathway - Cortex:
• Cell bodies of upper motor neurons are located in layer 5 of the cerebral cortex
Pathway - Cortex:
- Betz cells (_____ cells) – heavy _____ neurons that are _____ than other neurons from layer V of the cortex
- Betz cells end directlyon _____ _____ neurons in the _____hornof thespinal cord
- Other neurons from layer V synapse on _____ cells in the _____ horn of the spinal cord. Axons from the _____ cells end on _____ _____ neurons
Pathway - Cortex:
• Betz cells (pyramidal cells) – heavy myelinated* neurons that are bigger* than other neurons from layer V of the cortex.
*Carries the signals faster and more powerfully!
- Betz cells end directly on lower motor neurons in the ventral horn of the spinal cord
- Other neurons from layer V synapse on intermediate cells in the central horn of the spinal cord. Axons from the intermediate cells end on lower motor neurons
![](https://s3.amazonaws.com/brainscape-prod/system/cm/176/862/543/a_image_thumb.png?1453351183)
Upper Motor Neurons:
- are found at what levels?
- Dysfunction at these levels causes what?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/176/862/664/q_image_thumb.png?1453352007)
Upper Motor Neurons:
- Cortical, subcortical, or spinal levels
- Dysfunction at these levels can cause weakness, increased or pathologic reflexes, and increased tone and spasticity
![](https://s3.amazonaws.com/brainscape-prod/system/cm/176/862/664/a_image_thumb.png?1453351987)
Lower Motor Neurons:
- are found at what levels?
- Dysfunction at these levels causes what?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/176/863/349/q_image_thumb.png?1453352012)
Lower Motor Neurons:
- anterior horn cell, motor nerve root, plexus, peripheral nerve, or neuromuscular junction
- Dysfunction at these levels can cause weakness, atrophy, fasciculations, decreased reflexes
![](https://s3.amazonaws.com/brainscape-prod/system/cm/176/863/349/a_image_thumb.png?1453352013)
Pathway - Cortex:
Name the two corticospinal tracts and what they are involved in
Pathway - Cortex:
Both are descending corticospinal tracts!
- Lateral corticospinal tract – involved in limb muscle contraction
- Anterior corticospinal tract – involved in axial muscle contraction
![](https://s3.amazonaws.com/brainscape-prod/system/cm/176/863/553/a_image_thumb.png?1453352398)
Pathway - Cortex:
The descending corticospinal tract gives off co-lateral fibers to:
- Adjacent _____ cells
- The _____ nuclei, _____ nucleus, _____ nuclei, and _____ nucleus
- To the _____ formation
Pathway - Cortex:
The descending corticospinal tract gives off co-lateral fibers to:
- Adjacent cortical cells
- The basal nuclei, red nucleus, vestibular nuclei, and olivary nucleus
- To the reticular formation
![](https://s3.amazonaws.com/brainscape-prod/system/cm/176/863/750/a_image_thumb.png?1453352515)
Pathway - Cortex:
Contribution of cortical motor fibers from the cortex:
• ~___% of nerve fibers come from the primary motor cortex, ~___% come from the premotor and supplementary motor areas, ~___% come from the sensory cortex
Pathway - Cortex:
Contribution of cortical motor fibers from the cortex:
• ~30% of nerve fibers come from the primary motor cortex, ~30% come from the premotor and supplementary motor areas, ~40% come from the sensory* cortex
*sensory cortex fibers allow quick decisions (like if skin is burning, reflex to move it back)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/176/863/948/a_image_thumb.png?1453352743)
Cortex:
Understand the terms Homunculus and Somatotopic Arrangement
Cortex:
- Homunculus: Scale model of human body illustrating physiological, psychological or other characteristics
- Somatotopic Arrangement: Point to point correspondence of an area of the body to a specific point on the central nervous system
![](https://s3.amazonaws.com/brainscape-prod/system/cm/176/863/974/a_image_thumb.png?1453352940)
Which tracks deal with voluntary limb movement?
Lateral corticospinal
Anterior corticospinal
Rubrospinal