Lesson 6 Flashcards
3 principles of sensorimotor function
- hierarchically organized
- guided by sensory input.
- learning can change the nature and the locus of sensorimotor control.
company president (highest levels)
association cortex
company workers (lowest levels)
muscles
The tendency to be composed of different units
functional segregation
Similarity of Sensory and Sensorimotor Systems
Both have a parallel, functionally segregated, hierarchical system
Information flows down through the hierarchy
sensorimotor system
Information flows up through the hierarchy
sensory system
monitored responses of the body to stimuli that are fed back into the sensorimotor circuits
sensory feedback
importance of sensory feedback
directs the continuation of the responses that produced the feedback
Brief, all-or-none, high-speed movements that are not normally influenced by sensory feedback
ballistic movements
initial stages of motor learning
Each individual response is performed under conscious control
examples of acquired sensorimotor skills
- typing
- swimming
- knitting
- basketball playing
- dancing
- piano playing
At the top of the sensorimotor hierarchy
association cortex
2 major areas of association cortex
- posterior parietal association cortex
- dorsolateral prefrontal association cortex
plays an important role in:
1. integrating these two kinds of information
2. directing behavior by providing spatial information
3. directing attention
posterior parietal association cortex
posterior parietal association cortex is classified as association cortex since it receives input from more than one sensory system such as:
- visual system
- auditory system
- somatosensory system
A small area of prefrontal cortex that controls both eye movements and shifts in attention
frontal eye field
a disorder of voluntary movement that is not attributable to a simple motor deficit/to any deficit in comprehension or motivation
apraxia
involves a deficit in attention paid to one side of the visual field, usually the side that is contralateral/opposite to the damage
contralateral neglect
contralateral neglect affects the ____ region while apraxia affects the _____ region
- right
- left
unable to perform tasks or movements when asked but can readily perform under natural conditions (or when they are not thinking about what they are doing)
apraxia
often behave as if their world’s left side does not exist; often fail to recognize that they have a problem
contralateral neglect
2 contralateral neglects
- egocentric left
- object-based contralateral neglect
Failure to respond to the left side of objects (e.g., the left hand of the statue) even when the objects are presented horizontally or upside down
object-based contralateral neglect
deficits in responding occur for stimuli to the left of their own bodies,
egocentric left
sends projections to areas of secondary motor cortex, to primary motor cortex, and to the frontal eye field
dorsolateral prefrontal association cortex
dorsolateral prefrontal association cortex receives projections from the ______
posterior parietal cortex
receives much of their input from association cortex (PPAC & DPAC)
secondary motor cortex
secondary motor cortex sends much of their output to ____-
primary motor cortex
2 areas of secondary motor cortex
- supplementary motor area
- premotor cortex
selects and plans complex movements involving both sides of the body based on internal cues, such as thoughts or memory
supplementary motor area
process which typically elicits complex movements, often involving both sides of the body
electrical stimulation
anticipates and plans movements based on external sensory cues, such as responses to events that are seen or heard
premotor cortex
neurons that fire when an individual performs a particular goal-directed movement or when they observe the same goal directed movement performed by another
mirror neurons
major point of convergence of cortical sensorimotor signals
primary motor cortex
primary motor cortex directs _____ and executes the plans of the _______
- control of movements
- prefrontal cortex
primary motor cortex receives information from
- premotor cortex
- supplementary motor cortex
- somatosensory cortex
somatotopic map of the human primary motor cortex
motor homunculus
- tactile recognition
- perception of material qualities of an object by handling or lifting it
stereognosis
interact with different levels of the sensorimotor hierarchy; coordinate and modulate its activities
cerebellum and basal ganglia
important for habit formation, timing, attention, and coordination of movements
cerebellum
plays an important role in learning from one’s errors and in the prediction of errors.
cerebellar function
a complex heterogenous collection of interconnected nuclei
basal ganglia
influences motor cortex via a pathway through the thalamus
function of basal ganglia
the control of the speed and amplitude of movement based on motivational factors
movement vigor
_____ different pathways carry neural information from the primary motor cortex to the spinal cord’s motor neurons
4
2 (kinds of) pathways
- dorsolateral motor pathways
- ventromedial motor pathways
smallest units of motor activity
motor units
comprises hundreds of thousands of threadlike muscle fibers bound together in a tough membrane and attached to a bone by a tendon
skeletal muscle
released by motor neurons at neuromuscular junctions, activates the motor endplate on each muscle fiber and causes the fiber to contract
acetylcholine
motor neurons that innervate the fibers of a single muscle
motor pool
2 basic types of skeletal muscle fibers
- fast muscle fibers
- slow muscle fibers
contract and relax quickly; fatigue quickly because they are poorly vascularized
fast muscle fibers
capable of more sustained contraction because they are more richly vascularized
slow muscle fibers
2 categories of skeletal muscles
- flexators
- extensors
act to bend or flex a joint
flexators
act to straighten or extend
extensors
any two muscles whose contraction produces the same movement, be it flexion or extension
synergistic muscles
those that act in opposition (Ex: biceps and the triceps)
antagonistic muscles
2 types of muscle contraction
- isometric contraction
- dynamic contraction
a muscle contraction without a motion
isometric contraction
muscle contraction with a fixed amount of weight
dynamic contraction
2 types of receptors
- golgi tendon organs
- muscle spindles
embedded in the tendons
golgi tendon organs
embedded in the muscle tissue itself
muscle spindles
a reflex elicited by a sudden external stretching force on a muscle
stretch reflexes
patella =
knee
occurs when abrupt change arises in muscle length
patellar tendon reflex
an automatic response enacted to withdraw a limb from a painful stimulus
withdrawal reflexes
refers to the fact that antagonistic muscles are innervated in a way that permits a smooth, unimpeded motor response
reciprocal innervation
simultaneous activation of muscles on opposite sides of a joint
co-contraction
a negative feedback system that prevents rapid, repeated firing of the same motor neuron.
recurrent collateral inhibition
characteristics of central sensorimotor programs
- central sensorimotor programs are capable of motor equivalence
- sensory information that controls central sensorimotor programs is not necessarily conscious
- central sensorimotor programs can develop without practice
- practice can create central sensorimotor programs
