Dynamic response of human muscle spindle afferents to stretch during voluntary contraction

摘要: 1. The response of twenty-eight human muscle spindle afferents from m. extensor carpi radialis brevis to large amplitude ramp stretch and release at the wrist joint was recorded. dynamic index calculated as difference in firing rate between that just before end during subsequent static phase stretch. value steady voluntary contraction compared with relaxation. 2. In twenty-three primary afferents, increased eleven decreased twelve a range -8 +25 impulses s-1. five secondary change less than 2 3. abruptly stopped when released relaxed muscle. This cessation prevented seventeen afferents. 4. results suggest presence fusimotor actions on spindles contraction.