Lecture 13 Flashcards
Explain:
Beating Heart Illusion
- Cortical magnification reduced in V1 for peripheral vision
- Peripheral vision has low spatial awareness
- Brain updates the contours of the blurry heart constantly, makes heart appear larger and smaller
Describe:
Ventral-visual pathway
- Projects to the temporal lobe
- A visual pathway that can be tricked
What is the relationship between auditory cues and reaction times?
The louder the tone, the faster the reaction time
What does the reaction of clenching the teeth show?
Motor plans can come from subcortical structures
What is unique about subcortical responses?
Results from being startled, and below conscious threshold, meaning you cannot control it
What are the two components of the pyramidal tracts?
- Corticobulbar tract
- Corticospinal tract
Describe:
Upper motor neuron
- Cell body must be in cortex, and axon projects to spinal cord
- Contains over a million in the pyramidal tract
- Contains over a million axons of which most are myelinated - thus is fast
What does myelin support?
Speed of neural conduction
Where do the pyramidal tracts originate and what do they innervate?
- Originate in M1, SMA, PMA, parietal cortex, and some other cortical areas
- Primarily goes on to innervate alpha motor neurons, controlling muscles
What motor actions does the pyramidal tracts control?
Facial, axial (back and stomach, involved in posture), and intrinsic musculature (muscles of the hand and feet associated with fine digit control)
What allows for fast conduction of upper motor neurons? How fast?
- Size of the axons (diameter, length etc.)
- Myelination
- 100 m/s
What are the corticospinal tracts split into?
Ventral and lateral corticospinal tracts
Describe:
Corticobulbar tract
Contains upper motor nuerons that project in a region of the brain stem known as the “bulb”
What do upper motor neurons of the corticobulbar tract innervate?
Lower motor neurons that control facial muscles
What are lower motor neurons also known as?
Alpha motor neurons
Where does the corticobulbar tract extend from and to?
- Extends from M1
- Goes to the ‘bulb’
What is the ‘bulb’?
Brain stem