Exam 2 Flashcards
Which tract fibers cross gradually to the other side
Ipsilateral fibers
Which tract fibers cross immediately
Contralateral fibers
What percentage of corticospinal tract fibers originate from areas behind the central sulcus including the primary somatosensory cortex
40%
What percentage of corticospinal tract fibers originate from the precentral gyrus
60%
Greater than 1/2 of the primary motor cortex is devoted to control of what
Hands and speech
What assumes the least amount of space on the motor homonculous
Axial trunk/ equilibrium
A stroke that lesions the posterior limb internal capsule would be associated with what
Loss of movement
A stroke that lesions the post central gyrus would be associated with what
Loss of sensation
A stroke that lesions the occipital lobe would be associated with what
Loss of vision
If there is a lesion of the high brain stem also known as a decorticit lesion would have what clinical findings
Spasticity
If there is a lesion of the middle brain stem also known as a deceribrit lesion would have what clinical findings
Rigidity
If there is a lesion of the low brain stem also known as a spinal lesion would have what clinical findings
Flaccidity
Which brainstem area that receives stimulation from the vestibular nuclei and transmits excitatory signals to stimulate the axial trunk and extensor muscles that support the body against gravity
Pontine reticular nuclei
What nucleus stimulates extensor tone
Pontine reticular nuclei
What nuclei inhibits extensor tone
Medullary reticular nuclei
With regard to postural control, if descending cortical signals are blocked, what is expected result
Increased extensor tone
What is the function of dynamic signal from pyramidal cells to alpha motor neurons
Initiation of skeletal muscle contraction
What is true about postural reflexes
Impossible to separate from voluntary movements
Maintain body in up-right balanced position
Maintain stable postural background for voluntary movement
Adjustments include both static reflexes and physic reflexes
Can be altered with training
As the neck is rotated to the right what happens
Flexors facilitated on the left, extensors facilitated on the right
At the onset of clockwise rotation what would you expect happens in the VIII cranial nerve on the left side
Decrease in firing rate
After 20 clockwise rotations with the eyes closed on a revolving stool the subject is abruptly stopped and the eyes are opened. What is observed
Lateral nystagmus with the slow component clockwise
When supine head tilt is best detected by what
Saccule
What is used to detect head tilt when the person is upright, sitting or standing
Utricle
Signals from neck proprioceptors typically augment signals from the vestibular apparatus as the head and neck are rotated and have similar effects on limb flexion
False
In backward sway what sequence of contraction of muscles to maintain balance would occur
Tibialis, quadriceps and abdominals
When leaning forwards what is the sequence of muscle contractions
Gastronemius, hamstrings, then paraspinals
What would happen to a repetitive simple stretch reflex if when the muscle contracts it destabilizes posture
It would be inhibited
What are the spinal pathways discussed in class
Spinocerrebellar
Nigralstriatal
Rubrospinal
Which basal ganglia circuit plays a major role in cognitive control of motor activity
Caudate circuit
What circuit is related to muscle memory of learned movement
Putamen circuit
Ones sense of upright is generally a combination of cues that include both visual and vestibular formation
True
What effect does the striatum babe on the substantial nigra
Inhibitory GABA projections
Which area acts As a comparator, comparing intention with actual , motor performance and can effect the cerebellum via climbing fibers
Inferior olivary nucleus
Strong stimulation of one climbing fiber would elicit what
Complex action potential from a few purkinje cells
Spontaneous and continuous writhing movements is associated with a lesion in which are
Globus pallidis
Lesion in what region is related to hemiballism, violent random movments
Subthalamus
Lesion in which region is related to flicking, resting tremor (Parkinsonian tremor)
Putamen
A patient presents with a resting tremor, lead pipe rigidity in the extremities, voluntary movments are accurate but sllow where is the lesion likely found
Basal ganglia
Lesion in which area would be related to loss of control of emotions and rational
Hypothalamus
Lesion in which area is related to loss of control, paralysis
Brain stem