Using a Split-belt Treadmill to Evaluate Generalization of Human Locomotor Adaptation

Understanding the mechanisms underlying locomotor learning helps researchers and clinicians optimize gait retraining as part of motor rehabilitation. ...

Stony Brook University

Einstein Healthcare Network

New walking patterns can be learned over short time scales (i.e., adapted in minutes) using a split-belt treadmill that controls the speed of each leg independently. This leads to storage of a modified motor pattern that is expressed as an aftereffect in regular walking conditions and must be de-adapted to return to normal. Here we asked whether the nervous system adapts a general walking pattern that is used across many speeds or a specific pattern affecting only the two speeds experienced during split-belt training. In experiment 1, we tested three groups of healthy adult subjects walking at different split-belt speed combinations and then assessed aftereffects at a range of speeds. We found that aftereffects were largest at the slower speed that was used in split-belt training in all three groups, and it decayed gradually for all other speeds. Thus adaptation appeared to be more strongly linked to the slow walking speed. This result suggests a separation in the functional networks used for fast and slow walking. We tested this in experiment 2 by adapting walking to split belts and then determining how much fast regular walking washed out the slow aftereffect and vice versa. We found that 23-38% of the aftereffect remained regardless of which speed was washed out first. This demonstrates that there is only partial overlap in the functional networks coordinating different walking speeds. Taken together, our results suggest that there are some neural networks for controlling locomotion that are recruited specifically for fast versus slow walking in humans, similar to recent findings in other vertebrates.

Split-belt treadmill adaptation shows different functional networks for fast and slow human walking.

&#x513F;&#x7AE5;&#x5728;&#x5B66;&#x4E60;&#x4E2D;&#x7684;&#x8BED;&#x8A00; &#xFF1B; &#x663E;&#x793A;&#x6027;&#x65E9;&#x719F;&#x7684;&#x80FD;&#x529B;&#x8FD9;&#x662F;&#x8FD0;&#x52A8;&#x6280;&#x80FD;&#x5B66;&#x4E60;&#x7684;&#x60C5;&#x51B5;&#x5417;&#xFF1F;&#x6211;&#x4EEC;&#x7528;&#x62C6;&#x5206;&#x5E26;&#x6B65;&#x884C;&#x6765;&#x63A2;&#x6D4B;&#x7535;&#x673A;&#x9002;&#x5E94; &#xFF08;&#x8FD0;&#x52A8;&#x6280;&#x80FD;&#x5B66;&#x4E60;&#x7684;&#x7A97;&#x4F53;&#xFF09; &#x4E2D;&#x7684;&#x513F;&#x7AE5;&#x3002;&#x4ECE; 27 &#x513F;&#x7AE5; (&#x5E74;&#x9F84; 8 36 mo) &#x7684;&#x6570;&#x636E;&#x4F5C;&#x4E86;&#x6BD4;&#x8F83;&#x4E0E;&#x90A3;&#x4E9B;&#x4ECE; 10 &#x540D;&#x6210;&#x4EBA;&#x3002;&#x5B69;&#x5B50;&#x8D70;&#x4E0E;&#x8DD1;&#x6B65;&#x673A;&#x5E26;&#x4EE5;&#x76F8;&#x540C;&#x7684;&#x901F;&#x5EA6; &#xFF08;&#x7CFB;&#x5E26;&#xFF09;&#xFF0C;&#x5176;&#x6B21;&#x662F;&#x884C;&#x8D70;&#x65F6;&#x5E26;&#x79FB;&#x52A8;&#x4EE5;&#x4E0D;&#x540C;&#x7684;&#x901F;&#x5EA6; &#xFF08;&#x62C6;&#x5206;&#x5E26;&#xFF09; 8-10 &#x5206;&#x949F;&#xFF0C;&#x518D;&#x5176;&#x6B21;&#x662F;&#x7CFB;&#x5E26;&#x884C;&#x8D70; (postsplit)&#x3002;&#x6162;&#x6162;&#x5730;&#x51CF;&#x5C11;&#x4E86;&#x521D;&#x59CB;&#x4E0D;&#x5BF9;&#x79F0;&#x8BF1;&#x5BFC;&#x62C6;&#x5206;&#x5E26;&#x6B65;&#x884C;&#x7684;&#x65F6;&#x95F4;&#x534F;&#x8C03; &#xFF08;&#x5373;&#x53CC;&#x91CD;&#x652F;&#x6301;&#x65F6;&#x95F4;&#xFF09;&#xFF0C;&#x4E0E;&#x5927;&#x591A;&#x6570;&#x513F;&#x7AE5;&#x663E;&#x793A; postsplit &#x521D;&#x671F;&#xFF0C;&#x540E;&#x52B2; &#xFF08;&#x5373;&#x521D;&#x59CB;&#x5411;&#x76F8;&#x53CD;&#x7684;&#x65B9;&#x5411;&#x7684;&#x4E0D;&#x5BF9;&#x79F0;&#x6027;) &#x6307;&#x793A;&#x6027;&#x7684;&#x5B66;&#x4E60;&#x3002;&#x76F8;&#x6BD4;&#x4E4B;&#x4E0B;&#xFF0C;&#x5728;&#x62C6;&#x5206;&#x5E26;&#x884C;&#x8D70;&#x4E2D;&#x4FDD;&#x7559;&#x4E86;&#x7A7A;&#x95F4;&#x534F;&#x8C03; &#xFF08;&#x5373;&#x632F;&#x8361;&#x4E2D;&#x5FC3;&#xFF09; &#x7684;&#x4E0D;&#x5BF9;&#x79F0;&#x6027;&#xFF0C;&#x88AB;&#x89C6;&#x4E3A;&#x6CA1;&#x6709;&#x540E;&#x52B2;&#x3002;&#x6B65;&#x957F;&#xFF0C;&#x67D0;&#x79CD;&#x7A0B;&#x5EA6;&#x7684;&#x7A7A;&#x95F4;&#x548C;&#x65F6;&#x95F4;&#x7684;&#x534F;&#x8C03;&#xFF0C;&#x663E;&#x793A;&#x4E2D;&#x95F4;&#x7684;&#x5F71;&#x54CD;&#x3002;&#x65F6;&#x95F4;&#x8BFE;&#x7A0B;&#x5B66;&#x4E60;&#x7684;&#x53CC;&#x91CD;&#x652F;&#x6301;&#x548C;&#x6B65;&#x9AA4;&#x7684;&#x957F;&#x5EA6;&#x662F;&#x513F;&#x7AE5;&#x6BD4;&#x6210;&#x4EBA;&#x8981;&#x6162;&#x3002;&#x6B64;&#x5916;&#xFF0C;&#x8FD8;&#x6709;&#x521D;&#x59CB;&#x4E0D;&#x5BF9;&#x79F0;&#x7684;&#x65E9;&#x671F;&#x62C6;&#x5206;&#x5E26;&#x884C;&#x8D70;&#x671F;&#x95F4; &#xFF08;&#x79F0;&#x4E3A;&#x9519;&#x8BEF;&#xFF09; &#x7684;&#x5927;&#x5C0F;&#x548C;&#x6B65;&#x957F;&#x7684;&#x540E;&#x52B2;&#x663E;&#x8457;&#x8D1F;&#x76F8;&#x5173;&#x6027;&#x3002;&#x56E0;&#x6B64;&#xFF0C;&#x513F;&#x7AE5;&#x53EF;&#x80FD;&#x4F1A;&#x6709;&#x66F4;&#x591A;&#x5B66;&#x4E60;&#x65F6;&#x8BEF;&#x5DEE;&#x5F88;&#x5927;&#x7684;&#x56F0;&#x96BE;&#x3002;&#x8C03;&#x67E5;&#x7ED3;&#x679C;&#x8FDB;&#x4E00;&#x6B65;&#x8868;&#x660E;&#x63A7;&#x5236;&#x65F6;&#x95F4;&#x548C;&#x7A7A;&#x95F4;&#x7684;&#x9002;&#x5E94;&#x673A;&#x5236;&#x662F;&#x5728;&#x4E0D;&#x540C;&#x65F6;&#x95F4;&#x7684;&#x4E0D;&#x540C;&#x548C;&#x6210;&#x719F;&#x3002;

&#x884C;&#x8D70;&#x5728;&#x5E74;&#x5E7C;&#x513F;&#x7AE5;&#x7684;&#x9A6C;&#x8FBE;&#x9002;&#x5E94;&#x72EC;&#x7279;&#x7684;&#x7279;&#x70B9;&#x3002;

Children show precocious ability in the learning of languages; is this the case with motor learning? We used split-belt walking to probe motor adaptation (a form of motor learning) in children. Data from 27 children (ages 8-36 mo) were compared with those from 10 adults. Children walked with the treadmill belts at the same speed (tied belt), followed by walking with the belts moving at different speeds (split belt) for 8-10 min, followed again by tied-belt walking (postsplit). Initial asymmetries in temporal coordination (i.e., double support time) induced by split-belt walking were slowly reduced, with most children showing an aftereffect (i.e., asymmetry in the opposite direction to the initial) in the early postsplit period, indicative of learning. In contrast, asymmetries in spatial coordination (i.e., center of oscillation) persisted during split-belt walking and no aftereffect was seen. Step length, a measure of both spatial and temporal coordination, showed intermediate effects. The time course of learning in double support and step length was slower in children than in adults. Moreover, there was a significant negative correlation between the size of the initial asymmetry during early split-belt walking (called error) and the aftereffect for step length. Hence, children may have more difficulty learning when the errors are large. The findings further suggest that the mechanisms controlling temporal and spatial adaptation are different and mature at different times.

Unique characteristics of motor adaptation during walking in young children.

Enfants montrent une capacit&eacute; pr&eacute;coce dans l&#39;apprentissage des langues ; est-ce le cas avec l&#39;apprentissage moteur ? Nous avons utilis&eacute; la marche des courroies pour sonder l&#39;adaptation moteur (une forme d&#39;apprentissage moteur) chez les enfants. De 27 enfants (mo &acirc;ges 8-36) ont &eacute;t&eacute; compar&eacute;es avec celles de 10 adultes. Enfants marchaient avec les courroies de tapis roulant &agrave; la m&ecirc;me vitesse (ceinture attach&eacute;e), puis en marchant avec les ceintures se d&eacute;pla&ccedil;ant &agrave; des vitesses diff&eacute;rentes (ceinture de split) pour 8-10 min, suivi encore par ceinture attach&eacute;e &agrave; pied (postsplit). Asym&eacute;tries initiales dans la coordination temporelle (c.-&agrave;-d., support double temps) induite par la marche des courroies diminuait lentement, avec la plupart des enfants montrant un aftereffect (c.-&agrave;-d., l&#39;asym&eacute;trie dans la direction oppos&eacute;e &agrave; l&#39;initiale) dans le d&eacute;but de la p&eacute;riode postsplit, indicative de l&#39;apprentissage. En revanche, les asym&eacute;tries en coordination spatiale (c.-&agrave;-d., le centre d&#39;oscillation) ont persist&eacute; pendant la marche des courroies et aucun aftereffect a &eacute;t&eacute; observ&eacute;e. Longueur de l&#39;&eacute;tape, une certaine coordination spatiale et temporelle, ont montr&eacute; des effets interm&eacute;diaires. L&#39;&eacute;volution temporelle de l&#39;apprentissage en double longueur de prise en charge et l&#39;&eacute;tape a &eacute;t&eacute; plus lente chez les enfants que chez les adultes. En outre, il y avait une corr&eacute;lation n&eacute;gative significative entre la taille de l&#39;asym&eacute;trie initiale pendant d&eacute;but courroies marche (appel&eacute;e erreur) et l&#39;aftereffect pour la longueur de l&#39;&eacute;tape. Par cons&eacute;quent, enfants peuvent avoir plus de difficult&eacute;s apprentissage lorsque les erreurs sont grandes. Les r&eacute;sultats sugg&egrave;rent que les m&eacute;canismes qui contr&ocirc;lent l&#39;adaptation spatiale et temporelle sont matures et diff&eacute;rentes &agrave; des moments diff&eacute;rents.

Caract&eacute;ristiques uniques de l&#39;adaptation moteur pendant la marche chez les jeunes enfants.

Kinder zeigen fr&uuml;hreifen F&auml;higkeit in das Erlernen von Fremdsprachen; ist dies der Fall mit motorischen Lernens? Wir zur Untersuchung der motorischen Anpassung (eine Form des motorischen Lernens) bei Kindern verwendet Split-G&uuml;rtel zu Fu&szlig;. Daten aus 27 Kinder (Alter 8-36 Mo) wurden mit denen von 10 Erwachsenen verglichen. Kinder gingen mit der Laufb&auml;nder mit der gleichen Geschwindigkeit (gebundener G&uuml;rtel), gefolgt von Wandern mit den G&uuml;rteln verschieben mit verschiedenen Geschwindigkeiten (geteilte G&uuml;rtel) 8-10 min, wieder gefolgt von gebunden-G&uuml;rtel zu Fu&szlig; (Postsplit). Anf&auml;ngliche Asymmetrien in zeitlicher Abstimmung (d.h. doppelte Unterst&uuml;tzung Zeit) induziert durch Split-G&uuml;rtel zu Fu&szlig; wurden langsam reduziert, mit den meisten Kindern eine Aftereffect (d. h. Asymmetrie in entgegengesetzter Richtung zum urspr&uuml;nglichen) in der postsplit Zeit, indikative des Lernens zeigen. Im Gegensatz dazu Asymmetrien in r&auml;umliche Koordination (d. h. Mitte der Schwingung) beibehalten beim Split-G&uuml;rtel zu gehen und keine Aftereffect galt. Schrittl&auml;nge, ein gewisses Ma&szlig; an sowohl r&auml;umliche und zeitliche Koordination, zeigte zwischengeschalteten Effekte. Der zeitlichen Verlauf des Lernens in doppelte Unterst&uuml;tzung und Schritt L&auml;nge war langsamer bei Kindern als bei Erwachsenen. Dar&uuml;ber hinaus gab es eine signifikante negative Korrelation zwischen der Gr&ouml;&szlig;e der urspr&uuml;nglichen Asymmetrie w&auml;hrend der fr&uuml;hen Split-G&uuml;rtel zu Fu&szlig; (Fehler genannt) und die Aftereffect f&uuml;r Schrittl&auml;nge. Daher k&ouml;nnen Kinder haben Schwierigkeiten, lernen, wenn die Fehler gro&szlig; sind. Die Ergebnisse weiter deuten, dass die Mechanismen, die zeitliche und r&auml;umliche Anpassung Steuerung unterschiedlich und Reife zu unterschiedlichen Zeiten sind.

Besonderheiten der motorischen Anpassung beim gehen in den jungen Kindern.

I bambini mostrano abilit&agrave; precoce nell&#39;apprendimento delle lingue; &egrave; questo il caso con motore apprendimento? Abbiamo usato split-cintura camminando per sonda adattamento motore (una forma di apprendimento motore) nei bambini. Dati da 27 bambini (mo et&agrave; 8-36) sono stati confrontati con quelli da 10 adulti. Bambini camminato con le cinghie di tapis roulant alla stessa velocit&agrave; (legato cintura), seguita da camminare con le cinghie in movimento a velocit&agrave; diverse (split cintura) per 8-10 min, seguita nuovamente da cintura legata a piedi (postsplit). Asimmetrie iniziali in coordinamento temporale (cio&egrave;, supporto doppio tempo) indotta da Spalato-cintura camminando lentamente sono stati ridotti, con la maggior parte dei bambini mostrando un effetto collaterale (cio&egrave;, asimmetria nella direzione opposta per l&#39;iniziale) del periodo postsplit, indicativo di apprendimento. Al contrario, asimmetrie nel coordinamento spaziale (cio&egrave;, il centro di oscillazione) ha persisto durante la deambulazione split-cintura e nessun effetto collaterale &egrave; stato visto. Lunghezza del passo, una misura di coordinamento spaziale e temporale, hanno mostrato effetti intermedi. Il corso di tempo di apprendimento in doppio appoggio e passo lunghezza era pi&ugrave; lento nei bambini che negli adulti. Inoltre, c&#39;&egrave; stata una significativa correlazione negativa tra la dimensione dell&#39;asimmetria iniziale durante primo split-cintura a piedi (chiamato errore) e l&#39;effetto collaterale per la lunghezza del passo. Quindi, i bambini possono avere pi&ugrave; difficolt&agrave; di apprendimento quando gli errori sono grandi. Ulteriormente i risultati suggeriscono che i meccanismi di controllo di adattamento temporale e spaziale sono differenti e matura in tempi diversi.

Caratteristiche uniche di adattamento motore durante il cammino nei bambini piccoli.

&#x5B50;&#x4F9B;&#x306F;&#x3001;&#x8A00;&#x8A9E;&#x306E;&#x5B66;&#x7FD2;&#x306B;&#x65E9;&#x719F;&#x306E;&#x80FD;&#x529B;&#x3092;&#x793A;&#x3059;;&#x3053;&#x308C;&#x304C;&#x904B;&#x52D5;&#x5B66;&#x7FD2;&#x30B1;&#x30FC;&#x30B9;&#x3067;&#x3059;&#x304B;&#xFF1F;&#x6211;&#x3005; &#x30E2;&#x30FC;&#x30BF;&#x30FC;&#x306E;&#x9069;&#x5FDC; (&#x904B;&#x52D5;&#x5B66;&#x7FD2;&#x306E;&#x30D5;&#x30A9;&#x30FC;&#x30E0;) &#x5B50;&#x4F9B;&#x3067;&#x30D7;&#x30ED;&#x30FC;&#x30D6;&#x3092;&#x5206;&#x5272;&#x30D9;&#x30EB;&#x30C8;&#x3092;&#x6B69;&#x3044;&#x3066;&#x4F7F;&#x7528;&#x3002;27 &#x5B50;&#x4F9B; &#xFF08;&#x5E74;&#x9F62; 8-36 &#x30DF;&#x30BA;&#x30FC;&#x30EA;&#x5DDE;&#xFF09; &#x304B;&#x3089;&#x306E;&#x30C7;&#x30FC;&#x30BF; 10 &#x5927;&#x4EBA;&#x304B;&#x3089;&#x3068;&#x6BD4;&#x8F03;&#x3057;&#x307E;&#x3057;&#x305F;&#x3002;&#x5B50;&#x4F9B;&#x306F;&#x3001;&#x30C8;&#x30EC;&#x30C3;&#x30C9;&#x30DF;&#x30EB; &#x30D9;&#x30EB;&#x30C8;&#x306F;&#x79FB;&#x52D5;&#x306B;&#x7570;&#x306A;&#x308B;&#x901F;&#x5EA6; (&#x5206;&#x5272;&#x30D9;&#x30EB;&#x30C8;) 8-10 &#x5206;&#x9593;&#x3001;&#x518D;&#x5EA6;&#x7E1B;&#x3089;&#x30D9;&#x30EB;&#x30C8;&#x6B69;&#x884C;&#x304C;&#x7D9A;&#x304F;&#x30D9;&#x30EB;&#x30C8; (postsplit) &#x3092;&#x5F92;&#x6B69;&#x3067;&#x7D9A;&#x3044;&#x3066;&#x540C;&#x3058;&#x901F;&#x5EA6; (&#x7D50;&#x3070;&#x308C;&#x305F;&#x30D9;&#x30EB;&#x30C8;) &#x3068;&#x6B69;&#x3044;&#x305F;&#x3002;&#x521D;&#x671F;&#x306E;&#x975E;&#x5BFE;&#x79F0;&#x5206;&#x5272;&#x30D9;&#x30EB;&#x30C8;&#x3092;&#x6B69;&#x304F;&#x3053;&#x3068;&#x306B;&#x3088;&#x3063;&#x3066;&#x8A98;&#x8D77;&#x3055;&#x308C;&#x308B;&#x6642;&#x9593;&#x7684;&#x5354;&#x8ABF; &#xFF08;&#x3059;&#x306A;&#x308F;&#x3061;&#x3001;&#x30C0;&#x30D6;&#x30EB; &#x30B5;&#x30DD;&#x30FC;&#x30C8;&#x6642;&#x9593;&#xFF09; &#x3067;&#x3086;&#x3063;&#x304F;&#x308A;&#x3068;&#x307B;&#x3068;&#x3093;&#x3069;&#x306E;&#x5B50;&#x4F9B;&#x306F;&#x6B8B;&#x52B9; (&#x3059;&#x306A;&#x308F;&#x3061;&#x3001;&#x6700;&#x521D;&#x306B;&#x53CD;&#x5BFE;&#x65B9;&#x5411;&#x306B;&#x975E;&#x5BFE;&#x79F0;) postsplit &#x6642;&#x4EE3;&#x521D;&#x671F;&#x306B;&#x5B66;&#x7FD2;&#x306E;&#x6307;&#x6A19;&#x8868;&#x793A;&#x4E2D;&#x6E1B;&#x5C11;&#x3057;&#x307E;&#x3057;&#x305F;&#x3002;&#x5BFE;&#x7167;&#x7684;&#x306B;&#x3001;&#x7A7A;&#x9593;&#x30B3;&#x30FC;&#x30C7;&#x30A3;&#x30CD;&#x30FC;&#x30B7;&#x30E7;&#x30F3; (&#x3059;&#x306A;&#x308F;&#x3061;&#x3001;&#x767A;&#x632F;&#x306E;&#x4E2D;&#x5FC3;) &#x306B;&#x304A;&#x3051;&#x308B;&#x975E;&#x5BFE;&#x79F0;&#x5206;&#x5272;&#x30D9;&#x30EB;&#x30C8;&#x3092;&#x6B69;&#x884C;&#x4E2D;&#x306B;&#x6C38;&#x7D9A;&#x5316;&#x3057;&#x3001;&#x6B8B;&#x52B9;&#x306F;&#x8A8D;&#x3081;&#x3089;&#x308C;&#x306A;&#x304B;&#x3063;&#x305F;&#x3002;&#x7A7A;&#x9593;&#x3068;&#x6642;&#x9593;&#x306E;&#x8ABF;&#x6574;&#x306E;&#x30E1;&#x30B8;&#x30E3;&#x30FC; &#x30B9;&#x30C6;&#x30C3;&#x30D7;&#x9577;&#x4E2D;&#x9593;&#x52B9;&#x679C;&#x3092;&#x793A;&#x3057;&#x305F;&#x3002;&#x5B66;&#x7FD2;&#x306E;&#x30C0;&#x30D6;&#x30EB; &#x30B5;&#x30DD;&#x30FC;&#x30C8;&#x3068;&#x30B9;&#x30C6;&#x30C3;&#x30D7;&#x306E;&#x9577;&#x3055;&#x306E;&#x6642;&#x9593;&#x30B3;&#x30FC;&#x30B9;&#x3067;&#x5927;&#x4EBA;&#x306E;&#x5B50;&#x4F9B;&#x305F;&#x3061;&#x3088;&#x308A;&#x3082;&#x9045;&#x304B;&#x3063;&#x305F;&#x3002;&#x307E;&#x305F;&#x3001;(&#x30A8;&#x30E9;&#x30FC;&#x3068;&#x547C;&#x3070;&#x308C;&#x307E;&#x3059;) &#x30B5;&#x30A4;&#x30BA;&#x521D;&#x671F;&#x306E;&#x30B9;&#x30D7;&#x30EA;&#x30C3;&#x30C8;&#x306E;&#x30D9;&#x30EB;&#x30C8;&#x3092;&#x6B69;&#x884C;&#x4E2D;&#x306E;&#x521D;&#x671F;&#x306E;&#x975E;&#x5BFE;&#x79F0;&#x6027;&#x3068;&#x30B9;&#x30C6;&#x30C3;&#x30D7;&#x9577;&#x306E;&#x6B8B;&#x52B9;&#x306E;&#x9593;&#x306B;&#x8CA0;&#x306E;&#x76F8;&#x95A2;&#x304C;&#x3042;&#x3063;&#x305F;&#x3002;&#x3057;&#x305F;&#x304C;&#x3063;&#x3066;&#x3001;&#x5B50;&#x4F9B;&#x306F;&#x5B66;&#x7FD2;&#x8AA4;&#x5DEE;&#x304C;&#x5927;&#x304D;&#x3044;&#x3088;&#x308A;&#x591A;&#x304F;&#x306E;&#x56F0;&#x96E3;&#x304C;&#x3042;&#x308A;&#x307E;&#x3059;&#x3002;&#x305D;&#x308C;&#x4EE5;&#x4E0A;&#x306E;&#x6240;&#x898B;&#x306F;&#x6642;&#x7A7A;&#x306E;&#x9069;&#x5FDC;&#x5236;&#x5FA1;&#x3059;&#x308B;&#x30E1;&#x30AB;&#x30CB;&#x30BA;&#x30E0;&#x306F;&#x7570;&#x306A;&#x308B;&#x3068;&#x6210;&#x719F;&#x3057;&#x305F;&#x5225;&#x306E;&#x56DE;&#x3067;&#x3067;&#x3059;&#x304A;&#x52E7;&#x3081;&#x3057;&#x307E;&#x3059;&#x3002;

&#x5E7C;&#x5150;&#x306B;&#x304A;&#x3051;&#x308B;&#x6B69;&#x884C;&#x6642;&#x306E;&#x904B;&#x52D5;&#x9069;&#x5FDC;&#x306E;&#x30E6;&#x30CB;&#x30FC;&#x30AF;&#x306A;&#x7279;&#x6027;&#x3002;

&#xC544; &#xC774;&#xB4E4;&#xC740; &#xC5B8;&#xC5B4;; &#xD559;&#xC2B5;&#xC5D0;&#xC11C; &#xC870; &#xC219;&#xD55C; &#xB2A5;&#xB825; &#xD45C;&#xC2DC; &#xC774;&#xAC83;&#xC740; &#xBAA8;&#xD130; &#xD559;&#xC2B5;&#xC758; &#xACBD;&#xC6B0;? &#xC6B0;&#xB9AC; &#xC544;&#xC774; &#xB4E4;&#xC5D0; &#xC788;&#xB294; &#xBAA8;&#xD130; &#xC801;&#xC751; (&#xBAA8;&#xD130; &#xD559;&#xC2B5;&#xC758; &#xD615;&#xD0DC;)&#xB97C; &#xC870;&#xC0AC; &#xD558; &#xBD84;&#xD560; &#xBCA8;&#xD2B8; &#xAC78;&#xC5B4; &#xC0AC;&#xC6A9;. 27 &#xC5B4;&#xB9B0;&#xC774; (8-36 &#xC138; &#xBAA8;)&#xC5D0;&#xC11C; &#xB370;&#xC774;&#xD130; 10 &#xC131;&#xC778;&#xC5D0;&#xC11C; &#xBE44;&#xAD50; &#xB418;&#xC5C8;&#xB2E4;. &#xC544;&#xC774; &#xB4E4; &#xB4A4;&#xC5D0; &#xB2E4;&#xB978; &#xC18D;&#xB3C4; (&#xBD84;&#xD560; &#xBCA8;&#xD2B8;) 8-10 &#xBD84; &#xB4A4;&#xC5D0; &#xB2E4;&#xC2DC; &#xAC78;&#xC5B4; &#xBB36;&#xC5B4; &#xBCA8;&#xD2B8; &#xC774;&#xB3D9; &#xBCA8;&#xD2B8; (postsplit)&#xC640; &#xD568;&#xAED8; &#xAC77;&#xACE0; &#xAC19;&#xC740; &#xC18D;&#xB3C4; (&#xBB36;&#xC778;&#xB41C; &#xBCA8;&#xD2B8;), &#xB514;&#xB51C; &#xBC29; &#xC544; &#xBCA8;&#xD2B8;&#xC640; &#xD568;&#xAED8; &#xAC78;&#xC5B4;. &#xC2DC;&#xAC04; &#xC870;&#xC815; (&#xC989;, &#xC774;&#xC911; &#xC9C0;&#xC6D0; &#xC2DC;&#xAC04;) &#xBD84;&#xD560; &#xBCA8;&#xD2B8; &#xC0B0;&#xCC45;&#xC5D0; &#xC758;&#xD574; &#xC720;&#xB3C4; &#xB41C; &#xCD08;&#xAE30; asymmetries &#xD559;&#xC2B5;&#xC744; &#xB098;&#xD0C0;&#xB0B4;&#xB294; &#xCD08;&#xAE30; postsplit &#xAE30;&#xAC04;&#xC5D0; &#xD6C4;&#xC720;&#xC99D; &#xC138; &#xC8E0; (&#xC989;, &#xCD08;&#xAE30;&#xC5D0; &#xBC18;&#xB300; &#xBC29;&#xD5A5;&#xC73C;&#xB85C; &#xBE44;&#xB300;&#xCE6D;)&#xB97C; &#xBCF4;&#xC5EC;&#xC8FC;&#xB294; &#xB300;&#xBD80;&#xBD84;&#xC758; &#xC544;&#xC774; &#xB4E4;&#xACFC; &#xD568;&#xAED8; &#xCC9C;&#xCC9C;&#xD788; &#xAC10;&#xC18C; &#xB418;&#xC5C8;&#xB2E4;. &#xBC18;&#xBA74;, &#xACF5;&#xAC04; &#xC870;&#xC815; (&#xC989;, &#xC9C4;&#xB3D9;&#xC758; &#xC911;&#xC2EC;)&#xC5D0; asymmetries &#xBD84;&#xD560; &#xBCA8;&#xD2B8; &#xC0B0;&#xCC45; &#xD558;&#xB294; &#xB3D9;&#xC548; &#xC720;&#xC9C0; &#xD558; &#xACE0; &#xC544;&#xBB34; &#xC5EC;&#xD30C; &#xBCF4;&#xC600;&#xB2E4;. &#xB2E8;&#xACC4; &#xAE38;&#xC774;, &#xACF5;&#xAC04; &#xBC0F; &#xC2DC;&#xAC04; &#xC870;&#xC815;&#xC758; &#xC911;&#xAC04; &#xD6A8;&#xACFC; &#xBCF4;&#xC600;&#xB2E4;. &#xC774;&#xC911; &#xC9C0;&#xC6D0; &#xBC0F; &#xB2E8;&#xACC4; &#xAE38;&#xC774; &#xD559;&#xC2B5; &#xC2DC;&#xAC04; &#xACFC;&#xC815;&#xC740; &#xC131;&#xC778; &#xBCF4;&#xB2E4; &#xC544;&#xC774; &#xB4E4;&#xC5D0; &#xC788;&#xB294; &#xB290;&#xB9B0;. &#xB610;&#xD55C;, (&#xC624;&#xB958; &#xB77C;&#xACE0;) &#xCD08;&#xAE30; &#xBD84;&#xD560; &#xBCA8;&#xD2B8;&#xC5D0; &#xC0B0;&#xCC45; &#xD558;&#xB294; &#xB3D9;&#xC548; &#xCD08;&#xAE30; &#xBE44;&#xB300;&#xCE6D;&#xC758; &#xD06C;&#xAE30;&#xC640; &#xC5EC;&#xD30C; &#xB2E8;&#xACC4; &#xAE38;&#xC774; &#xB300; &#xD55C; &#xC911;&#xC694; &#xD55C; &#xBD80;&#xC815;&#xC801;&#xC778; &#xC0C1;&#xAD00; &#xAD00;&#xACC4;&#xB294;. &#xB530;&#xB77C;&#xC11C;, &#xC5B4;&#xB9B0;&#xC774; &#xD559;&#xC2B5; &#xC624;&#xB958;&#xB294; &#xD070; &#xB54C; &#xB354; &#xB9CE;&#xC740; &#xC5B4;&#xB824;&#xC6C0;&#xC744; &#xD560; &#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;. &#xACB0;&#xACFC; &#xCD94;&#xAC00; &#xC2DC;&#xAC04;&#xC801; &#xBC0F; &#xACF5;&#xAC04;&#xC801; &#xC801;&#xC751; &#xC81C;&#xC5B4; &#xBA54;&#xCEE4;&#xB2C8;&#xC998; &#xB2E4;&#xB974;&#xACE0; &#xC131;&#xC219; &#xC11C;&#xB85C; &#xB2E4;&#xB978; &#xC2DC;&#xAC04;&#xC5D0;&#xB294; &#xAC83;&#xC774; &#xC88B;&#xC2B5;&#xB2C8;&#xB2E4;.

&#xC5B4;&#xB9B0; &#xC544;&#xC774; &#xB4E4;&#xC5D0; &#xC788;&#xB294; &#xC0B0;&#xCC45; &#xD558;&#xB294; &#xB3D9;&#xC548; &#xBAA8;&#xD130; &#xC801;&#xC751;&#xC758; &#xACE0;&#xC720; &#xD2B9;&#xC131;.

Los ni&ntilde;os muestran capacidad precoz en el aprendizaje de idiomas; &iquest;es este el caso de aprendizaje motor? Sol&iacute;amos caminar split-correa sonda motor adaptaci&oacute;n (una forma de aprendizaje motor) en ni&ntilde;os. Datos de 27 ni&ntilde;os (mo de edades 8-36) se compararon con los de 10 adultos. Los ni&ntilde;os caminaron con las correas de cinta de correr a la misma velocidad (cintur&oacute;n atado), seguido por caminar con los cinturones m&oacute;viles a diferentes velocidades (split correa) durante 8-10 minutos, seguido nuevamente por correa atada a pie (postsplit). Asimetr&iacute;as iniciales en coordinaci&oacute;n temporal (es decir, tiempo de doble apoyo) inducida por split-correa caminando lentamente se redujeron, con la mayor&iacute;a de los ni&ntilde;os que muestran un efecto secundario (es decir, la asimetr&iacute;a en la direcci&oacute;n opuesta a la inicial) en el per&iacute;odo temprano de la postsplit, indicativo de aprendizaje. En contraste, las asimetr&iacute;as en la coordinaci&oacute;n espacial (es decir, centro de oscilaci&oacute;n) persistieron durante la marcha de split-correa y se observ&oacute; ning&uacute;n efecto secundario. Longitud de paso, una medida de coordinaci&oacute;n tanto espacial como temporal, mostr&oacute; efectos intermedios. El curso del aprendizaje de doble apoyo y paso largo tiempo era m&aacute;s lento en ni&ntilde;os que en adultos. Adem&aacute;s, hubo una correlaci&oacute;n negativa significativa entre el tama&ntilde;o de la asimetr&iacute;a inicial durante la temprana partida-correa caminando (llamado error) y el efecto secundario para el paso de largo. Por lo tanto, los ni&ntilde;os pueden tener m&aacute;s dificultades para aprender cuando los errores son grandes. Los resultados m&aacute;s futuros sugieren que los mecanismos que controlan la adaptaci&oacute;n temporal y espacial son diferentes y madura en diferentes momentos.

Caracter&iacute;sticas &uacute;nicas de la adaptaci&oacute;n de motor durante la marcha en ni&ntilde;os peque&ntilde;os.

New walking patterns can be learned over short timescales (i.e., adapted in minutes) using a split-belt treadmill that controls the speed of each leg independently. This leads to storage of a modified spatial and temporal motor pattern that is expressed as an aftereffect in regular walking conditions. Because split-belt walking is a novel task for adults and children alike, we used it to investigate how motor adaptation matures during human development. We also asked whether the immature pattern resembles that of people with cerebellar dysfunction, because we know that this adaptation depends on cerebellar integrity. Healthy children (3-18 years old) and adults, and individuals with cerebellar damage were adapted while walking on split belts (1:2 speed ratio). Adaptation and de-adaptation rates were quantified separately for temporal and spatial parameters. All healthy children and adults tested could learn the new timing at the same rate and showed significant aftereffects. However, children younger than 6 years old were unable to learn the new spatial coordination. Furthermore, children as old as age 11 years old showed slower rates of adaptation and de-adaptation of spatial parameters of walking. Young children showed patterns similar to cerebellar patients, with greater deficits in spatial versus temporal adaptation. Thus, although walking is a well-practiced, refined motor skill by late childhood (i.e., 11 years of age), the processes underlying learning new spatial relationships between the legs are still developing. The maturation of locomotor adaptation follows at least two time courses, which we propose is determined by the developmental state of the cerebellum.

Younger is not always better: development of locomotor adaptation from childhood to adulthood.

Upright stance has allowed for substantial flexibility in how the upper limbs interact with each other: the arms can be coordinated in alternating, synchronous, or asymmetric patterns. While synchronization is thought to be the default mode of coordination during bimanual movement, there is little evidence for any bilateral coupling during locomotor-like arm cycling movements. Multi-frequency tasks have been used to reveal bilateral coupling during bimanual movements, thus here we used a multi-frequency task to determine whether the arms are coupled during arm cycling. It was hypothesized that bilateral coupling would be revealed as changes in background EMG and cutaneous reflexes when temporal coordination was altered. Twelve subjects performed arm cycling at 1 and 2 Hz with one arm while the contralateral arm was either at rest, cycling at the same frequency, or cycling at a different frequency (i.e., multi-frequency cycling with one arm at 1 Hz and the other at 2 Hz). To evoke reflexes, the superficial radial nerve was stimulated at the wrist. EMG was collected continuously from muscles of both arms. Results showed that background EMG in the lower frequency arm was amplified while reflex amplitudes were unaltered during multi-frequency cycling. We propose that neural coupling between the arms aids in equalizing muscle activity during asymmetric tasks to permit stable movement. Conversely, such interactions between the arms would likely be unnecessary in determining a reflexive response to a perturbation of one arm. Therefore, bilateral coupling was expressed when it was relevant to symmetry.

Multi-frequency arm cycling reveals bilateral locomotor coupling to increase movement symmetry.

Adaptation is an error-driven motor learning process that can account for predictable changes in the environment (e.g., walking on ice) or in ourselves (e.g., injury). Our ability to recall and build upon adapted motor patterns across days is essential to this learning process. We investigated how different training paradigms affect the day-to-day memory of an adapted walking pattern. Healthy human adults walked on a split-belt treadmill, and returned the following day to assess recall, relearning rate, and performance. In the first experiment, one group adapted and de-adapted (i.e., washed-out the learning) several times on day 1 to practice the initial stage of learning where errors are large; another group adapted only one time and then practiced in the adapted ("learned") state where errors were small. On day 2, they performed washout trials before readapting. The group that repeatedly practiced the initial portion of adaptation where errors are large showed the fastest relearning on the second day. In fact, the memory was nearly as strong as that of a third group that was left overnight in the adapted state and was not washed-out before reexposure on the second day. This demonstrates that alternating exposures to early adaptation and washout can enhance readaptation. In the second experiment, we tested whether the opposite split-belt pattern interferes with day 2 relearning. Surprisingly, it did not, and instead was similar to practicing in the adapted state. These results show that the structure of the initial phase of learning influences the ease of motor relearning.

Motor adaptation training for faster relearning.

Human locomotor adaptation is necessary to maintain flexibility of walking. Several lines of research suggest that the cerebellum plays a critical role in motor adaptation. In this study we investigated the effects of noninvasive stimulation of the cerebellum to enhance locomotor adaptation. We found that anodal cerebellar transcranial direct current stimulation (tDCS) applied during adaptation expedited the adaptive process while cathodal cerebellar tDCS slowed it down, without affecting the rate of de-adaptation of the new locomotor pattern. Interestingly, cerebellar tDCS affected the adaptation rate of spatial but not temporal elements of walking. It may be that spatial and temporal control mechanisms are accessible through different neural circuits. Our results suggest that tDCS could be used as a tool to modulate locomotor training in neurological patients with gait impairments.

Modulating locomotor adaptation with cerebellar stimulation.

One step backwards, two steps ahead: amplifying movement errors to improve walking post-stroke.

Locomotor adaptation is a form of short-term learning that enables gait modifications and reduces movement errors when the environment changes. This adaptation is critical for community ambulation for example, when walking on different surfaces. While many individuals with traumatic brain injury (TBI) recover basic ambulation, less is known about recovery of more complex locomotor skills, like adaptation. The purpose of this study was to investigate how TBI affects locomotor adaptation.

Effects of traumatic brain injury on locomotor adaptation.

Movements learned in one set of conditions may not generalize to other conditions. For example, practicing walking on a split-belt treadmill subsequently changes coordination between the legs during normal ("tied-belt") treadmill walking; however, there is limited generalization of these aftereffects to natural walking over the ground. We hypothesized that generalization of split-belt treadmill adaptation to over-ground walking would be improved by maintaining consistency in other task variables, specifically gait speed. This hypothesis was based on our previous finding that treadmill aftereffect size was sensitive to gait speed: Aftereffects were largest when tested on tied-belts running at the same speed as the slower belt during split-belt adaptation. In the present study, healthy adults were assigned to a "slow" or "fast" over-ground walking group. Both groups adapted to split-belts (0.7:1.4 m/s), and treadmill aftereffects were tested on tied-belts at the slow (0.7 m/s) and fast (1.4 m/s) speeds. All participants were subsequently transferred to the over-ground environment. The slow and fast groups walked over-ground at 0.7 and 1.4 m/s, respectively. As in previous work, we found that the size of aftereffects during treadmill walking was speed-dependent, with larger aftereffects occurring at 0.7 m/s compared with 1.4 m/s. However, over-ground walking aftereffects were less sensitive to changes in gait speed. We also found that aftereffects in spatial coordination generalized more to over-ground walking than aftereffects in temporal coordination across all speeds of walking. This suggests that different factors influence aftereffect size in different walking environments and for different measures of coordination.

Erin V.L. Vasudevan

Physical Therapy,
School of Health Technology and Management,
Physical Therapy, School of Health Technology and Management

Stony Brook University

Using a Split-belt Treadmill to Evaluate Generalization of Human Locomotor Adaptation

Erin V.L. Vasudevan

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Physical Therapy,School of Health Technology and Management,Physical Therapy, School of Health Technology and Management

Stony Brook University

Using a Split-belt Treadmill to Evaluate Generalization of Human Locomotor Adaptation

Physical Therapy,
School of Health Technology and Management,
Physical Therapy, School of Health Technology and Management