Change in transfer function of joint receptor output

Shifts in kinesthesis through time and after active and passive movement

The position sense of a stationary arm was investigated subsequent to an horizontally adductive movement with axis the shoulder joint. The right arm was the treated arm: it reached a test position actively, using minimal voluntary effort, or passively from each of 10 starting positons. The blind-folded S localized the index finger of the treated arm by attempting to touch it with the index finger of his left hand. The results indicate that subsequent to active movement the final position of a limb is more accurately known than a position resulting from passive movement. A second finding is that concomitant with both forms of limb placement there is a unidirectional drift of perceived limb position over trials.

Adaptive changes of opposite sign in the oculomotor systems of the two eyes

Subjects inspected their feet via base-out prisms for 3 min. Using binocular vision, subsequent reaching without prisms showed significant overestimation of distance. Monocular testing showed a lateral shift in pointing to targets in opposite directions for each eye. This indicates that registered, as opposed to actual, convergence is a factor in near distance perception, and that opposite adaptation occurs within the motor control system for each eye.

Adaptation to prisms: do proprioceptive changes mediate adapted behaviour with ballistic arm movements?

In Experiment I subjects pointed repeatedly at a target viewed through laterally displacing prisms and received terminal visual feedback. In one task the pointing movements were slow (proprioceptively controlled), and in the other they were fast (pre-programmed). In both tasks adaptation proceeded at the same rate and to the same level of performance. Following fast pointing with prisms a large amount of arm-body adaptation was found with slow and fast test movements, while following slow pointing with prisms a large amount of arm-body adaptation was found with slow test movements, but only a small amount with fast test movements. The result suggests that adapted behaviour with preprogrammed movements is not mediated by a proprioceptive change. In Experiment II pointing movements were passive. No arm-body adaptation was found with fast test movements, and, contrary to expectation, only a small amount with slow test movements.