Data from: Proprioceptive interaction between the two arms in a single-arm pointing task

Proprioceptive signals coming from both arms are used to determine the
perceived position of one arm in a two-arm matching task. Here, we
examined whether the perceived position of one arm is affected by
proprioceptive signals from the other arm in a one-arm pointing task in
which participants specified the perceived position of an unseen reference
arm with an indicator paddle. Both arms were hidden from the participant’s
view throughout the study. In Experiment 1, with both arms placed in front
of the body, the participants received 70–80 Hz vibration to the elbow
flexors of the reference arm (= right arm) to induce the illusion of elbow
extension. This extension illusion was compared with that when the left
arm elbow flexors were vibrated or not. The degree of the
vibration-induced extension illusion of the right arm was reduced in the
presence of left arm vibration. In Experiment 2, we found that this
kinesthetic interaction between the two arms did not occur when the left
arm was vibrated in an abducted position. In Experiment 3, the
vibration-induced extension illusion of one arm was fully developed when
this arm was placed at an abducted position, indicating that the brain
receives increased proprioceptive input from a vibrated arm even if the
arm was abducted. Our results suggest that proprioceptive interaction
between the two arms occurs in a one-arm pointing task when the two arms
are aligned with one another. The position sense of one arm measured using
a pointer appears to include the influences of incoming information from
the other arm when both arms were placed in front of the body and parallel
to one another.