7. Motor Systems - 1 Motor Systems I Dr. Leonard Goals: To...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Motor Systems I Dr. Leonard Goals: • To introduce the central motor system • To understand some basic features of posture control and some roles of the brainstem in that process. To understand some roles of the cerebellum in the control of movement. I. Overview of the Central Motor Systems The perfectly executed spin of a dancer or the fade-away jump shot of a basketball player requires a complex and precisely coordinated sequence of muscle contractions working around numerous joints. These spectacular athletic feats and our own agility and dexterity all result from the remarkable ability of our motor system. Even in mundane behaviors like driving a car or in simple movements like raising your arm, we rely on the coordinated action of several muscle groups working around several joints. Perhaps most amazing is the fact that we don’t even have to consciously know “how” to make these movements - the sequence of muscle activation and their resulting forces are chosen “automatically” by our central motor system. The ability of our motor system to hide the true complexity of movement is partly revealed when we learn a new complex movement like playing an instrument. At the beginning, we need to carefully think about each finger movement, the precise placement, the precise orientation of our limbs and the precise duration the position is held. With practice the movements become successively more accurate and “easy” until they occur smoothly with little conscious effort (driving and riding a bicycle are other good examples). The control of motor behavior The movements of which our motor system are capable can roughly be divided into 3 classes: Voluntary movements Reading, playing the piano, driving etc. Are 1) purposeful and goal directed; 2) usually learned, improve with practice and as improve require less conscious effort; 3) They can be initiated in response to particular sensory experience or can be initiated at will. Reflex movements Knee jerk, coughing, withdrawal of hand from hot object, eyeblink in response to air puff. These are the 1) simplest behaviors and are under the least amount of voluntary control; 2) are rapid; 3) involuntary and usually controlled in a graded way by the eliciting stimulus. Rhythmic motor patterns Walking , Running, Chewing. These behaviors combine elements of reflex and voluntary control. Typically only the initiation and termination are controlled voluntarily. Once initiated these types of movements proceed almost automatically in a reflex-like fashion.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 Movements occur around joints Joints are lubricated contact points between bones. Muscles can only pull so actions around joints are controlled by agonist and antagonist muscles which pull from opposite sides of the joint. In each movement the primary mover (agonist muscle) is counterbalanced by the action of the antagonist muscle. This helps to stabilize and decelerate the movement. The motor system must take into account several tasks in orchestrating even simple
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/18/2008 for the course PHYS 1010 taught by Professor Thompson during the Fall '07 term at New York Medical College.

Page1 / 22

7. Motor Systems - 1 Motor Systems I Dr. Leonard Goals: To...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online