Lecture 6 - Voluntary Movement Flashcards
What is a simple model of motor control?
Sensory input -> processing -> motor response
What does the function of the brain in the nervous system?
It is the control center of the nervous system
What are the functions of the brain?
Memory, language, attention, emotions, movement
How has the brain evolved?
deep regions are responsible for more basic functions (breathing), further regions are responsible for simple functions (basic thought), furthest regions are more responsible for most complex functions (sensory info)
What is the function of the frontal cortex?
To receive information from the many brain areas and process it. Makes decisions/plans for movement
What is the most densely connected part of the brain?
The frontal cortex
What part of the brain is larger in humans than other animals?
The frontal cortex
What is reaction time?
A reflection of the amount of planning necessary to make movement. It is a base measure of how good you are at processing information
What is Fitts Law?
Movement time is directly related to target distance and inversely related to target size
Who was Wilder Penfield?
A neurophysiologist in the 1950’s who mapped out the motor cortex by using electrical stimulation to cause muscle contraction
What does an fMRI estimate?
The metabolism in neurons.
What is an fRMI used for?
To map blood flow in the brain and look at structure.
What is transcranial magnetic stimulation (TMS)?
A coiled figure 8 with a vertex that fires APs to produce movement
What is the function of the motor cortex?
To specify details of the movement such as direction, speed, and magnitude
What are the divisions of the motor cortex?
Premotor, supplementary motor, and primary motor.
What is the function of the premotor cortex?
Planning
What is the function of the supplementary cortex?
Help during complicated movement to give more processing power
What is the function of the primary motor cortex?
Plans direction, how far, and how fast
What is the motor homunculus?
Representation of how various parts of the body are represented in the motor cortex. Hands and mouth are the largest
Where is the cerebellum located?
Directly behind the brainstem, below the visual cortex
What is the cerebellum responsible for?
Coordination, balance, posture, and maintaining equilibrium
What is the basal ganglia?
Series of motor nuclei deep in the brain
What is the basal ganglia responsible for?
Movement regulation and skill learning
What is the left hemisphere responsible for?
Verbal, specification of force, the right side of the body
What is the right hemisphere responsible for?
Tactile discrimination, spatial discrimination, and the left side of the body
How do the left and right hemisphere communicate?
Through the corpus callosum
What is a callosotomy?
Cut of the corpus callosum to stop excessive electrical spread
What is a callosotomy used to treat?
Epilepsy
What is the function of the spinal chord?
“Information highway,” serves as a link between brain and PNS/muscles, does some information processing
What does the spinal chord consist of?
White matter and gray matter
What is white matter?
Myelinated axon fibers
Which region of the spinal chord can white matter be found?
In the ascending and descending tracts
What does gray matter consist of?
Cell bodies and unmyelinated fibers
Which region of the spinal chord can gray matter be found?
The H shape central region
Which root brings information to the spinal chord (afferent)?
Dorsal root
Which root brings information away from the spinal chord (efferent)?
Ventral root
Which side of the spinal chord can the dorsal root be found?
The back side
Which side of the spinal chord can the ventral root be found?
The front side
What does a motor unit consist of?
Motor neurons and all the muscle fibers it innervates
How many motor units are in a muscle?
The number of units varies based on function
How do motor units function?
All fibers contract simultaneously
What is recruitment?
The addition of motor units to increase force
How are motor units recruited?
Small first and then increasingly large (size principle)
What is firing frequency?
The increase in the firing rate of the neuron to increase the force
What is firing frequency known as?
“rate coding”
How can can muscle force be scaled?
Recruitment and firing frequency
