@inproceedings{Ellmer_ANCMC_2010,
  title = {Are reaching movements planned in kinematic or dynamic coordinates?},
  booktitle = {Abstracts of Neural Control of Movement Conference (NCM 2010)},
  abstract = {Whether human reaching movements are planned and optimized in kinematic
  (task space) or dynamic (joint or muscle space) coordinates is still an
  issue of debate. The first hypothesis implies that a planner produces a
  desired end-effector position at each point in time during the reaching
  movement, whereas the latter hypothesis includes the dynamics of the
  muscular-skeletal control system to produce a continuous end-effector
  trajectory.
  
  Previous work by Wolpert et al (1995) showed that when subjects were
  led to believe that their straight reaching paths corresponded to curved
  paths as shown on a computer screen, participants adapted the true path
  of their hand such that they would visually perceive a straight line 
  in visual space, despite that they actually produced a curved path.
  These results were interpreted as supporting the stance that reaching
  trajectories are planned in kinematic coordinates. However, this
  experiment could only demonstrate that adaptation to altered paths, i.e.
  the position of the end-effector, did occur, but not that the precise
  timing of end-effector position was equally planned, i.e., the trajectory. 
  Our current experiment aims at filling this gap by explicitly testing whether
  position over time, i.e. velocity, is a property of reaching movements
  that is planned in kinematic coordinates. 
  
  In the current experiment, the velocity profiles of cursor movements
  corresponding to the participant's hand motions were skewed either to
  the left or to the right; the path itself was left unaltered. 
  
  We developed an adaptation paradigm, where the skew of the velocity profile was
  introduced gradually and participants reported no awareness of any
  manipulation.
  Preliminary results indicate that the true hand motion of participants
  did not alter, i.e. there was no adaptation so as to counterbalance the
  introduced skew. However, for some participants, peak hand velocities
  were lowered for higher skews, which suggests that participants
  interpreted the manipulation as mere noise due to variance in their own
  movement.
  
  In summary, for a visuomotor transformation task, the hypothesis of a
  planned continuous end-effector trajectory predicts adaptation to a
  modified velocity profile. The current experiment found no systematic adaptation
  under such transformation, but did demonstrate an effect that is more in
  accordance that subjects could not perceive the manipulation and rather
  interpreted as an increase of noise.
  
  },
  address = {Naples, Florida, 2010},
  year = {2010},
  note = {clmc},
  slug = {ellmer_ancmc_2010},
  author = {Ellmer, A. and Schaal, S.},
  crossref = {p10422}
}