Simply moving one\u2019s own body, for instance by directing a hand toward a coffee cup, requires the orga\u00adni\u00adza\u00adtion of var\u00adious phys\u00adi\u00ado\u00adlog\u00adical sys\u00adtems including the cen\u00adtral and periph\u00aderal ner\u00advous sys\u00adtems and the mus\u00adcu\u00adloskeletal system.<\/p>\n Once the hand grasps and picks up the cup, the ques\u00adtions become even more com\u00adpli\u00adcated. What if the cup is filled with liquid? At this point, the com\u00adplexity of the con\u00adtrol problem bal\u00adloons \u2014 the pres\u00adence of the liquid intro\u00adduces non\u00adlinear fluid dynamics with the risk of a spill because of the inherent vari\u00adability in one\u2019s movement<\/strong>.<\/p>\n Sternad, a pro\u00adfessor of biology, elec\u00adtrical and com\u00adputer engi\u00adneering and\u00a0physics and post\u00addoc\u00adtoral researcher C.J. Hasson are inter\u00adested in how we adapt our move\u00adment strate\u00adgies when inter\u00adacting with dynamic objects in the environment.<\/p>\n In a recent paper pub\u00adlished in the Journal of Neu\u00adro\u00adphys\u00adi\u00adology<\/em>, Hasson and Sternad explored the ques\u00adtion by looking at the everyday task of manip\u00adu\u00adlating a cup of coffee. They show that how we adapt our move\u00adment strate\u00adgies is directly related to the amount of vari\u00adability and reli\u00ada\u00adbility in our sur\u00adround\u00adings and ourselves<\/strong>.<\/p>\n \u201cBecause we\u2019re humans and not machines, we\u2019re noisy and vari\u00adable,\u201d said Hasson. \u201cWe can\u2019t expect that a move\u00adment will unfold exactly as we planned\u00a0it.\u201d<\/p>\n For the study, 18 healthy par\u00adtic\u00adi\u00adpants vis\u00adited the Action Lab to play a video game, wherein they attempted to move a vir\u00adtual cup filled with vir\u00adtual liquid across a large video screen. Instead of a normal video-game con\u00adtroller, sub\u00adjects moved the vir\u00adtual cup by grasping a manip\u00adu\u00adlandum \u2014 a large robotic arm. Sim\u00adilar to the real-life sce\u00adnario, the robot sim\u00adu\u00adlated the forces one would feel from the weight of the object and the sloshing of the liquid in the\u00a0cup.<\/p>\n They asked par\u00adtic\u00adi\u00adpants to move the cup across the screen within a com\u00adfort\u00adable time of two sec\u00adonds, a task for which there is an infi\u00adnite number of pos\u00adsi\u00adbil\u00adi\u00adties. You could move fast for one second and slow for one second, slow for a half second and then fast for one and a half sec\u00adonds. The team hypoth\u00ade\u00adsized that par\u00adtic\u00adi\u00adpants would nat\u00adu\u00adrally adapt a safe move\u00adment strategy with prac\u00adtice \u2014 and they\u00a0did.<\/p>\n But the most intriguing result, said Hasson, was that the size of each participant\u2019s safety margin<\/strong> \u2014or how close they let the liquid get to the edge of the cup \u2014 could be pre\u00addicted by how vari\u00adable they were in their move\u00adments<\/strong>. Those with more vari\u00adability tended to adapt a \u201csafer\u201d strategy with a larger safety\u00a0margin.<\/p>\n \u201cIf you have a large safety margin and I move with a small margin, the ques\u00adtion is, \u2018Why am I more risky than you?\u2019\u201d Hasson said. \u201cWell, you may find that I am much more con\u00adsis\u00adtent in my move\u00adments, so I don\u2019t need a big safety margin. If you\u2019re more vari\u00adable, you need a larger safety\u00a0margin.\u201d<\/p>\n The results have impli\u00adca\u00adtions in assessing elderly patients and patients of motor dis\u00ador\u00adders such as cere\u00adbral palsy. \u201cIf vari\u00adability deter\u00admines the move\u00adments that you do, maybe that\u2019s an inter\u00adven\u00adtion point,\u201d said\u00a0Sternad.<\/p>\n Hasson will join Northeastern\u2019s physical-therapy fac\u00adulty in the fall. In his new role, he will look at learning and con\u00adtrol among older adults. \u201cIncreased vari\u00adability is a fun\u00adda\u00admental prop\u00aderty of older adults\u2019 neu\u00adro\u00admus\u00adcular sys\u00adtems, and as we\u2019ve estab\u00adlished, that will shape their move\u00adment strategies.\u201d<\/p><\/blockquote>\n","protected":false},"excerpt":{"rendered":" From the Northeastern University press release: Object manip\u00adu\u00adla\u00adtion or tool use is almost a uniquely human trait, said Dagmar Sternad, director of Northeastern\u2019s Action Lab, a research group inter\u00adested in… Read more »<\/a><\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[6],"tags":[42,18,12],"_links":{"self":[{"href":"https:\/\/therapytoronto.ca\/news\/wp-json\/wp\/v2\/posts\/3805"}],"collection":[{"href":"https:\/\/therapytoronto.ca\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/therapytoronto.ca\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/therapytoronto.ca\/news\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/therapytoronto.ca\/news\/wp-json\/wp\/v2\/comments?post=3805"}],"version-history":[{"count":3,"href":"https:\/\/therapytoronto.ca\/news\/wp-json\/wp\/v2\/posts\/3805\/revisions"}],"predecessor-version":[{"id":3840,"href":"https:\/\/therapytoronto.ca\/news\/wp-json\/wp\/v2\/posts\/3805\/revisions\/3840"}],"wp:attachment":[{"href":"https:\/\/therapytoronto.ca\/news\/wp-json\/wp\/v2\/media?parent=3805"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/therapytoronto.ca\/news\/wp-json\/wp\/v2\/categories?post=3805"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/therapytoronto.ca\/news\/wp-json\/wp\/v2\/tags?post=3805"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"\"](\"http:\/\/therapytoronto.ca\/images\/blogpics\/WomanHoldingMug.jpg\" "\\"holding")
Object manip\u00adu\u00adla\u00adtion or tool use is almost a uniquely human trait<\/strong>, said Dagmar Sternad, director of Northeastern\u2019s Action Lab, a research group inter\u00adested in move\u00adment coor\u00addi\u00adna\u00adtion. \u201cNot only does it require cer\u00adtain cog\u00adni\u00adtive abil\u00adi\u00adties but also dis\u00adtinct motor abilities<\/strong>.\u201d<\/p>\n