Amputees learn impossible movement of their phantom limb

© GL Moseley Interdependence of movement and anatomy persists when amputees learn a physiologically impossible movement of their phantom limb www.bodyinmind.com.au Moseley & Brugger (2009) Proc. Natl Acad. Sci. USA doi:10.1073/pnas.0907151106 (2009)

We measured reaction time (RT) during left/right judgments of pictured hands, when the intact and phantom hands were positioned like this: Resting position www.bodyinmind.com.au © GL Moseley Moseley & Brugger (2009) Proc. Natl Acad. Sci. USA doi:10.1073/pnas.0907151106 (2009)

We measured RT during left/right judgments of pictured hands, when the intact and phantom hands were positioned like this*: *The reason we do Resting this is because the longer it takes to position move between the position the hand is in and the position the We were interested in RT’s for these pictures: hand in the photograph is in, the longer the reaction time to make a Image correct judgment position becomes. www.bodyinmind.com.au See Parsons LM. Integrating cognitive psychology, © GL Moseley neurology and neuroimaging. Acta Psychol (Amst) 2001;107(1-3):155-181 to learn about this. Moseley & Brugger (2009) Proc. Natl Acad. Sci. USA doi:10.1073/pnas.0907151106 (2009)

We grouped RT’s when the resting hand & the pictured hand were in the same position: Resting position Image position www.bodyinmind.com.au © GL Moseley Moseley & Brugger (2009) Proc. Natl Acad. Sci. USA doi:10.1073/pnas.0907151106 (2009)

We grouped RT’s when the resting hand & the pictured hand were in the same position:and the opposite position position Resting position Image position www.bodyinmind.com.au © GL Moseley Moseley & Brugger (2009) Proc. Natl Acad. Sci. USA doi:10.1073/pnas.0907151106 (2009)

A A I A I A I 4 RT (sec) 0 Resting position Image position This shows that, as we would predict, when the hand or phantom hand, was in the same position as the hand in the photograph was, the reaction time is fast. When it is in the opposite position (as far as the impossible movement is concerned) the reaction time is slow. www.bodyinmind.com.au © GL Moseley Moseley & Brugger (2009) Proc. Natl Acad. Sci. USA doi:10.1073/pnas.0907151106 (2009)

The experiment. Participants Days 7 14 21 28 a b c d e www.BodyinMind.com.au f g Moseley & Brugger (2009) Proc. Natl Acad. Sci. USA doi:10.1073/pnas.0907151106 (2009)

Amp. A I A I 4 Intact RT This shows the 4 (sec) subjects who said they * * could do the impossible * * movement with their Pre Post 0 phantom were not lying. That is, it shows that, now they can move from Resting position the resting position to the position shown in Image position the photograph, using a very short trajectory (ie, the impossible way). www.bodyinmind.com.au Successes were quicker when pictured hand was opposite to resting position, but ONLY for the phantom side and ONLY after training. © GL Moseley Moseley & Brugger (2009) Proc. Natl Acad. Sci. USA doi:10.1073/pnas.0907151106 (2009)

On the right: a drawing showing a new phantom hand with an axis through the wrist into the hand. Two participants reported this. In both, it slowed their reaction Axis time to make a left/right judgment, but only if the resting position of the phantom was bent to one side and the image showed a hand bent the other way. This makes sense if you think that their is an axis effectively ‘blocking’ the movement. So, again, they weren’t lying! Two reported a new axis in their phantom. © GL Moseley www.bodyinmind.com.au Moseley & Brugger (2009) Proc. Natl Acad. Sci. USA doi:10.1073/pnas.0907151106 (2009)

On the right: a drawing showing a new phantom hand with an axis through the wrist into the hand. Two participants reported this. In both, it slowed their reaction Axis time to make a left/right judgment, but only if the resting position of the phantom was bent to one side and the image showed a hand bent the other way. This makes sense if you think that their is an axis effectively ‘blocking’ the movement. So, again, they weren’t lying! Pre Post 4 RT (sec) * * 0 Resting position Two reported a new axis in their Image position phantom. © GL Moseley www.bodyinmind.com.au Moseley & Brugger (2009) Proc. Natl Acad. Sci. USA doi:10.1073/pnas.0907151106 (2009)

On the right: a drawing showing a new phantom hand with an axis through the wrist into the hand. Two participants reported this. In both, it slowed their reaction Axis time to make a left/right judgment, but only if the resting position of the phantom was bent to one side and the image showed a hand bent the other way. This makes sense if you think that their is an axis effectively ‘blocking’ the movement. So, again, they weren’t lying! Pre Post 4 This impeded their RT capacity to move (sec) * * their hand sideways. 0 Resting position Two reported a new axis in their Image position phantom. © GL Moseley www.bodyinmind.com.au Moseley & Brugger (2009) Proc. Natl Acad. Sci. USA doi:10.1073/pnas.0907151106 (2009)

So what? The physical characteristics of your body image may affect how your brain works your body. www.bodyinmind.com.au © GL Moseley Moseley & Brugger (2009) Proc. Natl Acad. Sci. USA doi:10.1073/pnas.0907151106 (2009)

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Amputees learn impossible movement of their phantom limb

by BodyIn Mind on Nov 04, 2009

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Amputees learn impossible movement of their phantom limb — Presentation Transcript