Perturbation-induced fast drifts in finger enslaving

The Nature of Finger Enslaving: New Results and Their Implications

“…When all the fingers of the hand were lifted or lowered (by 1 cm over 0.5 s), the finger forces changed toward higher or lower magnitudes, respectively (see also Martin et al, 2011;Wilhelm et al, 2013). This was associated with much faster drifts in enslaving toward higher magnitudes, over 1-2 s, with the general pattern and magnitude of drifts being similar to those observed during spontaneous drifts (Ricotta et al, 2021).…”

“…In stark contrast to this assumption, a series of recent studies have demonstrated unintentional (and unperceived!) drifts in enslaving that happen over very brief time intervals (Abolins et al, 2020b;Hirose et al, 2020;Ricotta et al, 2021). These observations have documented a large increase in indices of enslaving highly consistent across conditions and subjects.…”

“…Such drifts can reach very large magnitude, up to 40% of the initial force level, with the subject being unaware of the force change. In recent studies (Abolins et al, 2020b;Cuadra et al, 2021;Hirose et al, 2020;Ricotta et al, 2021) with force production by a subset of fingers of a hand, showing visual feedback on the force produced by the instructed fingers (master fingers) led to a drift in the force produced by the enslaved fingers toward higher magnitudes. In contrast, when visual feedback on the enslaved finger force was provided (the subjects were unaware of the feedback manipulations due to adjustments in the feedback gain), the master finger force drifted to lower magnitudes.…”