Exam 2 - Sensorimotor system Flashcards
Like the sensory systems, the sensorimotor system is
A) hierarchical.
B) parallel.
C) functionally segregated.
D) all of the above
D
The supplementary motor area and the premotor cortex are in the
A) frontal lobe.
B) temporal lobe.
C) parietal lobe.
D) occipital lobe.
A
Electrical stimulation to any part of secondary motor cortex elicits
A) discrete movements of individual muscles.
B) discrete movements of individual joints.
C) complex movements, often involving both sides of the body.
D) loss of equilibrium.
C
Major outputs of both the premotor cortex and the supplementary motor area go to the
A) secondary motor cortex.
B) primary motor cortex.
C) somatosensory cortex.
D) frontal eye fields.
B
It has been estimated that over half the neurons of the brain are in a structure that constitutes only 10% of the brain’s total mass. This structure is the
A) neocortex.
B) cerebellum.
C) hippocampus.
D) brain stem.
B
Posterior parietal association cortex, what information does it receive, what does it output to?
- spatial awareness (position of limbs, external objects)
- receives visual, auditory, and somatosensory information
- outputs to motor cortex
Apraxia, what is it usually due to?
- disorder of voluntary movement, problem only evident when instructed to perform an action
- usually due to damage on the L side due to stroke
Contralateral neglect
- unable to respond to stimuli contralateral to the side of the lesion, usually seen with large lesions on the right
- damage to R side = neglect to L side of body and vice versa
- ex: shaving one side of your face
Dorsolateral prefrontal association cortex, what does it evaluate, what does it output to?
- planning and sequencing
- evaluates external stimuli and initiates voluntary reactions
- output to secondary motor cortex
What does the secondary motor cortex get input from and send output to?
- input from association cortex
- output to primary motor cortex
What are the 8 different areas of the secondary motor cortex?
- 3 supplementary motor areas
- 2 premotor areas
- 3 cingulate motor areas
Mirror neurons
- active when performing an action or watching another perform the same action
- important for empathy and social cognition
Stereognosis
recognizing by touch
Somatotopic
more cortex devoted to body parts which make many movements
Cerebellum, where does it receive input from?
- involved in fine-tuning and motor learning, cognitive response, and coordinating rapid movements
- receives input from primary and secondary motor cortex, and brain stem motor nuclei
Basal ganglia
- part of neural loops that receive cortical input and send output back via the thalamus
- modulate motor output and cognitive functions
- fine tune movements
Descending motor pathways - dorsolateral tracts
- limbs, distal muscles, and fine tune movements
- terminates in one spinal segment
Descending motor pathways - ventromedial tracts
- proximal muscles, posture and whole-body movement (gross motor and trunk movements)
- bilateral innervation
Motor unit
a motor neuron + muscle fibers, all fibers contract when motor neuron fires
Fast muscle fibers
fatigue quickly - like a sprinter
Slow muscle fibers
capable of sustained contraction due to vascularization - like a long distance runner
Flexors
bend or flex a joint
Extensors
straighten or extend
Synergistic muscles
any 2 muscles whose contraction produces the same movements
Antagonistic muscles
any 2 muscles that act in opposition
Golgi tendon organs
detect muscle tension
Muscle spindles
detect length of muscles (stretch)
What is the difference in the stretch and withdrawal reflex?
- stretch is monosynaptic and withdrawal is multisynaptic
Reciprocal innervation
antagonistic muscles interact so that movements are smooth
Response chunking
practice combines the central programs controlling individual response
- getting better with practice
Response shifting
shifts control to lower levels, freeing up higher levels to do more complex tasks
