Chapter 11 Flashcards
neuroprosthetics
computer assisted devices replace lost biological function
computer brain interface (CBI)
employs electrical signals from a computer to instruct the brain
brain computer brain interface (BCBI)
combine the BCI and CBI approaches
brain computer inferface
employs electrical signals from the brain to direct computer controlled devices
Major components of the motor system?
cerebrum (forebrain); brainstem; spinal cord
cerebrum
contributes to our conscious control of movement
Brainstem & Spinal cord
perform our more automatic movements
what happens if the brainstem or spinal cord is impaired?
the forebrain can imagine move- ments but can no longer produce them
Visual systems role in picking up object
relays this information through somatosensory regions of the neocortex to the motor regions of the neocortex that plan and initiate the movement.
basal ganglia’s role in picking up object
produces appropriate amount of force when picking up an object
brain stem & cerebellum’s role in picking up object
helps to regulate the timing and accuracy of the movement.
8 steps to pick up object
1 Visual information required to locate the target.
2 Frontal-lobe motor areas plan the reach and command the movement.
3 Spinal cord carries information to the hand
4 Motor neurons carry message to muscles of the hand and forearm
5 Sensory receptors on the fingers send message to sensory cortex saying that the cup has been grasped
6 Spinal cord carries sensory information to the brain.
7 Basal ganglia judge grasp forces, and cerebellum corrects movement errors.
8 Sensory cortex receives message that the cup has been grasped.
Afferent
somatosensory information travels from the body inward via the somatic nervous system
efferent
movement information travels out of the central nervous system
cross section of spinal cord: Outer part
consists of white matter; dorsal tracts are sensory and ventral tracts are motor
cross section of spinal cord: inner part
gray matter; shaped like a butterfly;
tracts
bundles of nerve fibers in the CNS
nerves
bundles of nerve fibers in the PNS
dermatomes
cervical, thoracic, lumbar, sacral, coccygeal
Nervous system organization
hypothesized to be organized in a number of levels, Successively higher levels control more complex aspects of behavior by acting through the lower levels. The three major levels: forebrain, brainstem, and spinal cord. Proposed that further levels of organization exist within these divisions,
Do higher levels replace lower levels?
no, they act by controlling them
Motor sequence
Movement modules preprogrammed by the brain and produced as a unit.
Mirror Neuron
cell in the primate premotor cortex that fires when an individual observes a specific action taken by another individual
frontal lobe
responsible for planning and initiating motor sequences
Prefrontal Cortex
plans complex behavior; specifies the goal not the specific movements
Where does the prefrontal cortex send instructions?
premotor cortex
premotor cortex
which produces the appropriate complex movement se- quences.
Primary Motor Cortex
produces specific movements
Movement Hierarchy
After the prefrontal cortex has for- mulated a plan of action, it instructs the premotor cortex to organize the appropriate sequence of behaviors, and the primary motor cortex executes the movements
What does the brainstem control?
species typical behaviors (actions displayed by every member of a species); also produce complex patterns of adaptive behavior. These patterns include movements used in eat- ing and drinking and in sexual behavior)
effect of context
how the neural site stimulated interacts both with the object presented and with the stimulation’s duration.
How do we know that the brainstem is involved in species typical behavior?
Stimulation of some brainstem sites produces behavior that depends on context, suggesting that an important function of the brainstem is to produce appropriate species-typical behavior.
locked-in syndrome
patient is aware and awake but cannot move or communicate verbally due to complete paralysis of nearly all voluntary muscles except the muscles of the eyes.
cerebral palsy
a disorder primarily of motor function: voluntary movements become difficult to make whereas conscious behavior controlled by the cortex may remain intact.
anoxia
lack of oxygen
cerebral palsy
group of brain disorders that result from brain damage acquired perinatally (at or near birth).
quadriplegia
paralysis of the legs and arms due to spinal-cord injury.
paraplegia
paralysis of the legs due to spinal- cord injury.
scratch reflex
automatic response in which an animal’s hind limb reaches to remove a stimulus from the surface of the body.
severed spinal cord
spinal reflexes still function, even though the spinal cord is cut off from communication with the brain. As a result, the paralyzed limbs may display spontaneous movements or spasms.
Homunculus
representation of the human body in the sensory or motor cortex; also any topographical representation of the body by a neural area.
Is there 1 or 2 motor cortex?
2; one on each side of body
motor cortex control movement on contralateral or ipsilateral part of body?
contalateral
Topographic Organization
Neural spatial representation of the body or areas of the sensory world perceived by a sensory organ; functional layout of the primary motor cortex
What does the motor cortex represent
the motor cortex represents not muscles but rather a repertoire of fundamental movement categories.
what does the motor cortex encode?
motor cortex maps appear to represent basic “types” of movement that learning and practice can modify. In other words, the motor cortex encodes not muscle twitches but a “lexicon,” or dictionary, of movements that is not large
Motor cortex neurons
take part in planning the movement as well as initiating