مفهوم مدلهاي داخلي در مغز ارائه: فاطمه ياوري استاد...

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باسمه تعالي. مفهوم مدلهاي داخلي در مغز ارائه: فاطمه ياوري استاد راهنما: جناب آقاي دکتر توحيدخواه ارديبهشت 91. 1. 2. 3. 4. فهرست مطالب. مقدمه. مدلهاي داخلي، کاربرد آنها و شواهد موجود. مرور برخي از مدلهاي محاسباتي مدولار. محاسبه مدلهاي داخلي در مغز. مقدمه. - PowerPoint PPT Presentation

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Diapositiva 1

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http://www.columbiampl.org/index.htmlhttp://www.cns.atr.jp/~kawato/

http://www.shadmehrlab.org/

http://thorlab.seas.wustl.edu/http://www.icn.ucl.ac.uk/motorcontrol/http://www.cs.washington.edu/homes/todorov/ () ... ...

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7 () . . 7 . . .

21- [Morraso & Mussa-Ivaldi 1982].2- [Schmidt et al. 1979].3- [Feldman 1966]. 1

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14 ( 2-1). [Katayama & Kawato 1993, Kawato & Gomi 1992, Shidara et al. 1993]. . [Wolpert et al. 1995, Mehta & Schaal 2002, Jordan & Rumelhart 1992, Towhidkhah 1996 & 1997]. ================================ : . .

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.Kawato & Gomi 1992

Katayama & Kawato 1993

Shidara et al. 1993

15: . . ( ) ( ) . . . : . . -------------------------------------------------------------------------------------------: ( gain) mpc . ( ) . . gain . . ( ). G/(1+GH) G 1/H . . (feedback linearization) G/(1+GH) G G 1/H . . .

( 2-1). [Katayama & Kawato 1993, Kawato & Gomi 1992, Shidara et al. 1993]. .

15 : ()Towhidkhah 1993 & 1996Wolpert et al. 1995Mehta & Schaal 2002 ().

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[Wolpert et al. 1995, Mehta & Schaal 2002, Jordan & Rumelhart 1992, Towhidkhah 1996 & 1997]. . ================================ : .16 (1999) : . . . : ()3

Bhushan & Shadmehr 1999Kawato 1999Wolpert & Ghahramani 2000 .17 [Bhushan & Shadmehr 1999, Wolpert & Kawato 1998, Kawato 1999, Wolpert & Ghahramani 2000].=============== . . CNS co existence co adaptation .

17 . (Mental Practice). .

18 task EMG . EMG . . .19 lower (16-22 Hz) (9-14 Hz) EEG .

19 task () . . MI 30% .

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2121 (1)22

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22 (2)UCL 23

One study used two robots to trick the brain into reacting to a self-tickle as if it were an external tickle.2 In the left hand, participants held an object attached to the first robot. This was connected to a second robot, attached to which was a piece of foam that delivered a touch stimulus to the palm of the right hand. Movement of the participant's left hand therefore caused movement of the foam, as if by remote control. The robotic interface was used to introduce time delays between the movement of the participant's left hand and the touch sensation on the right palm, and participants were asked to rate the "tickliness" (Figure 3). When there was no time delay, the condition was equivalent to a self-produced tickle because the participant determined the instant delivery of the touch stimulus by movements of the left hand. Greater delay between the causal action and the sensory effect (up to 300 ms) meant participants experienced the touch as more tickly.This suggests that, when there is no time delay, the brain can accurately predict the touch stimulus so that the sensory effect is attenuated. Introducing a time delay increases the likelihood of a discrepancy between the predicted and actual sensory effect. As a result, there is less attenuation of the tickly sensation, which tricks the brain into labeling the stimulus as external. By making the consequences of our own action unpredictable, therefore, the brain treats the self as another.

When you try to tickle yourself, the cerebellum predicts the sensation and this prediction is used to cancel the response of other brain areas to the tickle.

23 (3)Grip Force-Load Force Coupling

24 (4)Nowak et al (2006) 25

Sagittal MRI of H.K.s brain revealed almost complete absence of the cerebellum100ms after the balls impact cerebellar patient, HK, who does not have a cerebellum due to a rare developmental problem (H.K.s brain revealed almost complete absence of the cerebellum)Both groups of subjects showed a similar response in the delay and force. However, when the researcher asked the subjects to drop the ball themselves and again catch the ball in the force transducer, the cerebellar patient and healthy patients showed differences in their response. Healthy subjects made predictions of the impact of the ball and had a profound shortening of the reaction time. Subject HK, however did not seem to make anticipations and had similar response delays as in the first situation in which the experimenter dropped the ball.

Three healthy right-handed female subjects (aged 59, 63 and 65 years) served as a control group25Task I26

Task II27

Results Task II28

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30 . deadapt adapt .

31 ( 1997)32

MOSAIC (Imamizu & Kawato 2009)33

. MOSAIC . : ( F) ( I) MOSAIC . . . context . . .

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35 : 90 . . 90

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40 train . catch trial .41 catch

42train :Tape: (: : ) : * train *

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PD( ) . PD . . PD .2 45 (3) M1 PD PD (M1) Primary Motor Cortex . M1 .

462 PD "" " " .

46 2. : = () . gi . . K K

47 : / . 4848 : . : . : . 49 " " . . [Lackner & DiZio 1994]. . CNS .

49 50