Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
28 Cards in this Set
- Front
- Back
What is required for successful movement?
|
1. feedback, 2. control of muscle contraction, 3. coordination of muscle activity, 4. motor system should calibrate based on learning
|
|
What are the actions of the motor system?
|
Basic reflex
Central reflex Voluntary movements |
|
How does the nervous system perform motor actions?
|
Feedback and Feed-forward
|
|
What is feedback used for?
|
Slow movements and to maintain posture.
|
|
What is feedforward used for?
|
to perform anticipatory actions and allows for rapid movements
|
|
what are the three levels of suprasegmental control?
|
The spinal cord, brainstem, and forebrain
|
|
where are motoneurons controlling axial muscles?
|
In the ventromedial horn
|
|
Which two tracts innervate primarily medial motor neurons?
|
Reticulospinal and Vestibulospinal tracts
|
|
Which spinal tract innvervates primarily lateral motor neurons in animals?
|
The rubrospinal tract (from the red nucleus to the spinal cord)
|
|
What has replaced the rubrospinal tract in humans?
|
the corticospinal tract
|
|
Neurons in the ___________ give rise to the ventral corticospinal pathway and innvervate primarily medial neurons in the spinal cord bilaterally, as well as neurons in the reticular and vestibular nuclei
|
Premotor cortex and neck and trunk regions
|
|
The lateral corticospinal tract originates where?
|
In the primary motor cortex, as well as from somatosensory cortices.
|
|
Three quarters of the axons (in humans) cross the midline in the _____.
|
Pyramidal decussation
|
|
Lesions of the suprasegmental motor system produces what symptoms?
|
Weakness, loss of voluntary strength, slowing of musclar contraction and loss of fractionation.
|
|
What are the characteristics of spasticity?
|
Increased muscle tone, hyperactive stretch reflexes, and clonus (oscillatory muscle responses to muscle stretching).
|
|
Where is spasticity more marked?
|
In antigravity muscles
|
|
Describe decerebrate rigidity.
|
Condition in which there is increased muscle tone in the extensors of the arms and legs. (Loss of descending inhibition)
|
|
What reduces spasticity and what does this suggest?
|
lesioning the dorsal root afferents reduces spasticity and this suggests that it results from an increased gain in the spinal reflexes
|
|
Give the example used to describe the production of reflexes that are normally suppressed.
|
Babinski reflex
|
|
What is the result of lesions that involve pathways that control upper limb muscles?
|
Loss of the ability to control fine finger movements.
|
|
In Parkinson's disease, why are the reflexes not affected?
|
Becauses the disease affects a extrapyramidal motor system (the basal ganglia in this case), so the corticospinal tract is not involved.
|
|
What are the three classes of sensory inputs for postural responses?
|
Proprioceptors, vestibular receptors, and anticipatory postural reflexes
|
|
Transection where can produce decerebrate rigidity?
|
Above the vestibular nuceli and below the red nucleus
|
|
Walking movements :
|
1. are generated in the spine, 2. do not require suprasegmental inputs, 3. do not require sensory input, but 4. can have individual component movemets that are graded by afferent inputs.
|
|
Name the region of the brain that will stimulate walking on a treadmill
|
Mesencephalon Locomotor Region (MLR)
|
|
How does visual information affect locomotion?
|
It affects it by modulating the output of the motor cortex.
|
|
What is the fundamental influence driving locomotion?
|
A type of nueronal circuit called a central pattern generator.
|
|
Where are the central pattern generating neurons thought to reside?
|
In the intermediate gray matter of the spinal cord.
|