The EffĘcts of In Partial 3ėĄLfil1n€nt of Tle B€qüireûents for Eh ...

voluntary u¡skil-I€d movenênts .der€ ini-tiateú by thê
associatíoa cort€x vhÍclì ¡'Je.rë first tra¡sfêrêd tÕ the
motor cort€x a¡d tber throìlgà tle pyrani4al tract do1rn tÐ
the spinal notoE cent€rs. f¡e finã1 cutcoûe '{as chsc.ked
by ttìe assÕciaticå corter ria the seEsory paf-h¡rays, ?his
systen of ccntrol is ã 'larg€ negativ€ feedback loop
ttforned Èhraugh the eaternal. sorld'r {fto,1970). During
the learning phase, tb€ c€rebral cortex is continuously
araf,e cf Èhe systenrs performance aÃd adjustment are Baðe
as required. r,iith suf fic̀nt traini.ng, the perf,ormance
cf the CArs b€come refiÈ€d vÕl-untary skill-ed rnovements.
The large negatis€ fê€dback J,oop via lhe extêrnaL íor1ä
is reFlace¡l by an intêrnal oÌìe trpassing tbrough the
cerebellun lih:ch ¡rcald s€ q€ as a ûoàel of thê conbina-
tion cf tbe spinal motor systên,th€ êxternal r¡orld and
th+ ,sensory pêth*ays[, Yhus the oxj.gj"na]- legative feed-
back system j.s corì v€rted by learai*g into a feedford
systå¡D flhlch no longer dep€nd on a stEaig¡tford negatj-ve
feedback lcop frou the output to the i¡put. Àilditional
j.!ìput path{ays to th€ ce¡ebell-ì¡û s€ry€s to adjlrst t}re
internal norl€Ì as requ.ir€d in a ser eonech ani sn- li ke
syst êm "
fn tbe contêxt ot ItÐrs a nal ysis, cerebel lar ilysn€tria
a¡d int€ntionai- tr€aor rere vi-e¡,e d. as a result of
loss or :uFairnert of th€ irternal qodel. The iepair ê¡t
Hould na!:it€st itselt in the oterall perf ori¡ance of a
system {hj.cb ¡ltilized a .largê ¡egative feerlþack loop vith
a ccn.p1€x t¡ansfer functicr. As is shoun in the metho(l
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