Neurobiologi och fysiologi Flashcards
How do Schmidt and Lee (2005) define a motor program?
“A motor program is an abstract representation of movement that centrally organizes and controls the many degrees of freedom involved in performing an action”
Which three pieces of evidence for the existience of motor programs do Schmidt and Lee (2005) emphasize?
- Processing of afferent information (feedback) is too slow for on-going regulation of rapid movements.
- Reaction time (time between “go” signal and movement initiation) increases with movement complexity, suggesting that movements are planned in advance.
- Movement is possible even without feedback from the moving limb.
Describe William James’ (1890) theory of response chaining
The response-chaining, or reflex-chaining hypothesis, was one of the earliest descriptions of movement control. This open-loop hypothesis postulated that movements required attention only for initiation of the first action. As such, each subsequent movement was thought be automatically triggered by response-produced afferent information from the muscles.
What was the name of William James’ theory of movement control?
The “response-chaining” or “reflex-chaining” hypothesis
Who proposed the schema theory for motor control?
Richard Schmidt (1975)
How can the schema theory for motor control be briefly summarized?
A motor program containing general rules can be applied to different environmental or situational contexts via the involvement of open-loop control process and generalized motor programs.
What is a generalized motor program?
A GMP is thought to contain an abstract representation for a class of movements with invariant features pertaining to the order of events, the relative timing of events and the relative force with which events are produced. In order to determine how a particular movement should be performed, parameters such as overall movement duration, overall force of contractions and the muscles involved are specified to the GMP. This revision of the motor program concept allows many different movements to be produced with the same motor program as well as the production of novel movements by specifying new parameters.
According to Schmidt (1975), which four things are stored in memory after an individual generates a movement?
- The initial conditions of the movement, such as the proprioceptive information of the limbs and body.
- The response specifications for the motor programs, which are the parameters used in the generalized motor program, such as speed and force.
- The sensory consequences of the response, which contain information about how the movement felt, looked and sounded.
- The outcome of that movement, which contains information of the actual outcome of the movement with knowledge of results (KR).
What is a central pattern generator (CPG)?
Central pattern generators (CPGs) are neural networks that produce rhythmic patterned outputs without sensory feedback. They play an important role in respiration, swallowing, locomotion, etc. CPGs have been shown to produce rhythmic outputs resembling normal “rhythmic motor pattern production” even in isolation from motor and sensory feedback from limbs and other muscle targets.
Where are CPGs found?
Although anatomical details of CPGs are specifically known in only a few cases, they have been shown to originate from the spinal cords of various vertebrates and to depend on relatively small and autonomous neural networks (rather than the entire nervous system) to generate rhythmic patterns.
Var i hjärnan sker “rörelsens förberedelse”?
Laterala premotorcortex
Var i hjärnan sker “rörelsens utförande”?
Primära motorcortex
Var sker “selektionsprocessen” i utförandet av ett motoriskt program?
I basala ganglierna, som inhiberar och fungerar som ett slags “filter” för motoriska impulser
What are the the Rexed laminae?
The Rexed laminae comprise a system of ten layers of grey matter (I-X), identified in the early 1950s by Bror Rexed to label portions of the spinal cord.
