GE CLST 73B Lecture Notes - Lecture 8: Central Pattern Generator, Muscle Spindle, Withdrawal Reflex
29 Oct 2018
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Document Summary
Why are muscle spindles important in motor control. During any movement the brain initiates alpha-gamma motoneuron activation. Gamma moto neurons only synapse on spindle intra fusil fiber. they make sure that the muscle spindles remain sensitive because to have immediate reflexes we need it to be sensitive. Muslce spindles relay limb position information to higher centers. Muscle spindle activity from contracting muscle doesn"t relay much position information normally. Muscle spindle activity and passive length change from antagonist does relay joint angle position. If you stretch a muscle, you can dissect out the 1a afferent which shows spindles outputs are proportional to the lengthening. Spindles are good length detectors but you"re going to get joint angle information via the antagonist. Reflexes of muscle origin are different from withdrawal reflexes. Fras innervate the receptor organs mediate pain. When you step on a tack it is dysynaptic. Does not have direct access to the motor neuron.
