Chapter 6 (lectures 8-10) Flashcards
Frontal Lobe
decision making and critical thought
Central sulcus
separating the parietal lobe from the frontal lobe and the primary motor cortex from the primary somatosensory cortex
Parietal lobe
Integrates visual signals
Wernicke’s area
speech understanding
Temporal lobe
Auditory cortex
Broca’s area
Speech production
Divisions of the nervous system
1) central NS: nervous tissue within the brain and spinal cord
2) periphral NS: nerve tissue outside the brain and spinal cord
Functional types of neruons
1) sensory (afferent) neurons: send signals from the senses to the CNS
2) motor (efferent) neurons: carry signals from the brain or spinal cord to the periphery
Motor Unit
- a motor neuron and all of the muscle fibers it innervates
- generally, the fewer fibers in the motor unit, the more precise the moment
How can we increase force output?
1) Recruitment: simply recruit, or activate a greater number of motor units, usually activated and deactivated in sequence (size principle)
2) rate coding: to vary force by means of altering the frequency of motor unit firing , muscle force increases when the frequency of firing increases
Cerebellum
- receives afferent input from muscles, tendons, joints
- responsible for the regulation of force, range, and rate of movement
- associated problems” ataxia, gait disturbances
Basal ganglia
- involved in:
- retrieval and activation of movement plans
- scaling the amplitude of movement
- perceptual motor integration
- more recent evidence that the BG involved in cognitive processes such as memory and attention
- associated problems: huntington’s disease, parkinson’s disease
Motor cortex (primary)
- a band that stretches across the top of the cerebral cortex
- was the first place that localized brain function was found (penfield and rasmussen, 1950)
- appears to be a trigger for movement (one of the last areas to be active prior to movement)
Pre-motor cortex
- shown to send efferent signals to the proximal musculature
- helps with preplanning and stability
Supplementary motor cortex
- important in planning movements
- shown to be active before the premotor area
is practing with a weighted bat a good idea?
no, the player mentally feels like they hit better but they actually do not.
the brain adjusts for a different scenario than game scenarios
control system for open loop control
sensory system
-learned movements are translated into open loop control
How do we learn tasks that require open loop control?
start with closed loop control and feedback, and it is translated into open control
how does the executive know which muscles to activate
- timing
- force
The executive
-has a package of instructions called the program that gets sent to the effector
the effector
carries out the instructions sent from the executive
Response chaining hypothesis
- variant of open-loop control
- each subsequent movement was thought to be automatically triggered by response-produced afferent information from the muscles.
deafferentation
-disrupting the flow of sensory information into the body
Ian Waterman and proprioception
- 19yr old who contracted flu
- when he woke up he could not feel his body
- virus destroyed the dorsal nerves that carry sensory information
Central control of rapid movements
-triple burst EMG; burst of agonist muscle, then the agonist is turned off and the antagonist is turned on (bringing the limb to a stop)
Degrees of freedom problems
-concern is that the system has too many independent states that must be controlled at the same time
Motor Program
- a set of muscle commands that are structured before a movement sequence begins, and that allows the sequence to be carried out uninfluenced by peripheral feedback
Motor program evidence
- Slater-hammel (1960)
- clocked swept around and finger had to be lifted at right time
- on random trials the sweep was stopped before and then the next time it was stopped after
Point of no return
- the inability to sometimes inhibit programmed action
- point of no return in motor program
Function of motor program
- structure and issue movement commands
- organize the many components of the motor system into a single functional unit in order to produce desired action
Storage problem of motor control
where are all the motor programs stored?
the novelty problem of motor control
how do we do things when we are just learning them?
The generalized motor program
- proposed by schmidt
- accounts for the ability to adapt to motor programs to adapt to different situations or environmental factors
- contains invariant features and flexible features
Invariant features
- unique to individual
- sequence of movements
- amount of force used
- relative timing
Parameters (flexible features)
- change from situation to situation
- defines how the GMP is executed
- ex. time to carry out the task
- ex. the size of the movement
GMP and Schemas
- when you perform a skill/movement 4 main things are evaluated by the CNS
1. initial conditions
2. response specification
3. sensory consequences of the movement
4. end result of the movement - development of schemas allows for the comparator to function
GMP summary
- learner decides what movement to execute in a given situation by subconsciously retrieving the program from memory based on the existing schema and parameters
- desired movement is organized and carried out
- motor program can be carried out using open or closed loop control
Schema theory
- variability will enhance learning
- two types
1. recall
2. recognition
Recall schema
organizing the motor program so it can initiate the movement and control movement
it updates the system
recognition schema
- assess and compare the outcome using sensory information
- it revises the system
Errors in motor programs
Selection errors: choosing the wrong motor program
Execution errors: executed by the wrong motor skill
Other motor control theories
- internal models
- information processing theory
- equilibrium point hypothesis
- optimal control
