docSpecificity of Visuomotor Adaptation to Movement Dynamics. Society
download 
Report Transcription
Specificity of Visuomotor Adaptation to Movement Dynamics. Society
Specificity of Visuomotor Adaptation to Movement Dynamics Matthew J. Crossley Jiang Lan Fan Richard B. Ivry Hand Baseline Rotation Washout Trial CCW CW Hand Angle Movement Speed Time (ms) Trial 2-Target Pause - Compensation for opposing rotations: Yes - Gradual washout: No - Adaptation is modestly attenuated for shared start locations Trial 2-Target Static - Compensation for opposing rotations: Yes - Gradual washout: No - Marked increase/decrease in RT at onset/offset of rotation (not shown) References Herzfeld, D. J., Vaswani P. A., Marko, M. K., & Shadmehr, R. (2014). A memory of errors in sensorimotor learning. Science 345, 1349-1353. Howard, I. S., Ingram, J. N., Franklin, D. W., & Wolpert, D. M. (2012). Gone in 0.6 seconds: the encoding of motor memories depends on recent sensorimotor states. The Journal of Neuroscience, 32(37), 12756-12768. Howard, I. S., Wolpert, D. M., & Franklin, D. W. (2013). The effect of contextual cues on the encoding of motor memories. Journal of neurophysiology, 109(10), 2632-2644. Morehead, R. M., Crossley, M. J., & Ivry, R. B. (in prep). Savings upon re-aiming in visuomotor adaptation. CCW CW CW CCW CCW CW No Rotation CCW Rotation Movement Speed Time (ms) Rotation 1 Washout Rotation 2 Rotation 1 Rotation 2 CCW Time (ms) Retention via dynamic cues observed with gradual perturbation 4-Target Dyno - Compensation for opposing rotations: Yes - Gradual washout: Yes Gradual Trial Hand Angle CW Example Trial Rotation 2 Trial AAB - Re-adaptation may proceed slightly faster than adaptation - Memory for errors (Herzfeld et al., 2014)? - Explicit awareness due to novel rotation direction + novel context? Dynamic cue facilitation extends to multiple dynamic cues Hand Angle Movement Speed CCW Rotation Rotation 1 Baseline CCW Example Trial Rotation direction cued by visual landmark CCW Rotation Rotation 2 Trial ABA - Re-adaptation begins approximately where original adaptation finished - Retention is near perfect with different washout context Hand Angle CW 1 Sec Dwell Washout CW Trial No Rotation Rotation 1 CW CW Example Trial Opposing VM rotations prevent motor adaptation Baseline Dynamic cue facilitation is prevented by1s pause in movement CCW Rotation 2 Trial AAA - Re-adaptation proceeds at the same pace as original adaptation - Consistent with prior observation of no savings after complete washout of a 15 degree rotation (Morehead, Crossley, Ivry, in prep) 2-Target Dyno - Compensation for opposing rotations: Yes - Gradual washout: Yes - Adaptation is modestly attenuated for shared start locations Target - Participants move a cursor by moving a digital pen on a digitizing tablet - Vision of hand is occluded - Baseline & Washout phase: Cursor position is mapped veridically to hand position - Rotation phases: Cursor position is rotated relative to hand position - Adaptation indicated by: 1. Successful compensation for the rotated cursor during the adaptation phase 2. Gradual "washout" when the rotation is turned off Hand Angle Time (ms) Rotation 1 Gradual-Dwell Hand Angle Cursor Rotation 2 CCW Example Trial CCW Rotation Washout CW CW No Rotation Rotation 1 Hand Angle Gradual washout Hand Angle Compensation for rotation Baseline Hand Angle Visuomotor adaptation gradually tunes motor commands to reduce experienced errors CCW Adaptation via dynamic cues is acquired and retained independently Hand Angle Trial-by-trial switching between opposing sensorimotor perturbations impairs adaptation. However, opposing force fields can be learned if field direction is signaled by unique start locations (Howard et al., J Neurophysiology 2012). We show: 1. Opposing visuomotor rotations can also be adapted to if they are signaled by unique start locations (henceforth called "dynamic cues" or simply ”contexts”, following Howard et al.) 2. Adaptation via dynamic cues exhibits marked within-session retention 3. Retention via dynamic cues also observed with gradual perturbations Dynamic cues facilitate adaptation to opposing VM rotations Movement Speed Introduction Trial Adaptation to gradual rotation: 1. Prevented by a 1s pause 2. Retained with little decay Trial
