%0 Journal Article %A Rochelle Ackerley %A LĂ©onard Samain-Aupic %A Edith Ribot-Ciscar %T Passive proprioceptive training alters the sensitivity of muscle spindles to imposed movements %D 2022 %R 10.1523/ENEURO.0249-21.2021 %J eneuro %P ENEURO.0249-21.2021 %X Humans rely on precise proprioceptive feedback from our muscles to perform daily activities, which is important in both the acquisition and execution of movements. Somatosensory input from the body shapes motor learning through central processes, as demonstrated for tasks using the arm, under active (self-generated) and passive conditions. Presently, we investigated whether passive movement training of the ankle increased proprioceptive acuity (psychophysical experiment) and whether it changed the peripheral proprioceptive afferent signal (microneurography experiment). In the psychophysical experiment, the ankle of 32 healthy human participants was moved passively using pairs of ramp-and-hold movements in different directions. In a pre-training test, participants made judgements about the movement direction in a two-alternative forced choice paradigm. Participants then underwent passive movement training, but only half were cued for learning, where a reference position was signaled by a sound and the participant had to learn to recognize this position; they then completed a post-training test. In a paradigm using the same setup, 9 healthy participants underwent microneurography recordings of Ia muscle afferents from the peroneal nerve, where all were cued during training. In the psychophysical experiment, proprioceptive acuity improved with training only in the cued group. In the microneurography experiment, we found that muscle afferent firing was modulated, via an increase in the dynamic index, after training. We suggest that changes in muscle afferent input from the periphery can contribute to and support central perceptual and motor learning, as shown under passive conditions using ankle movements, which may be exploited for movement rehabilitation.Significance StatementWhen you train your body to execute a movement, from walking to a complex sequence of movements required in sport, you develop your sense of movement (i.e. proprioception), to provide accurate feedback for precise control. This can be acquired actively or passively, through the modification of central processes. Here, we show that training induced through passive ankle movements can increase perceptual proprioceptive acuity and that these changes are, at least in part, signaled in the periphery, directly from muscle afferent firing. This has potential implications in movement rehabilitation, especially concerning the leg and foot, and for those who have difficulties in self-generating movements. %U https://www.eneuro.org/content/eneuro/early/2022/01/10/ENEURO.0249-21.2021.full.pdf