▁part ▁is ▁maintained . ▁This ▁phenomen on ▁corresponds ▁with ▁an ▁imp air ment ▁in ▁the ▁prem ot or ▁mechanism ▁manif ested ▁tempor ally ▁by ▁the ▁appearance ▁of ▁the ▁read iness ▁potential ▁record able ▁on ▁the ▁scal p ▁several ▁hundred ▁mill iseconds ▁before ▁the ▁over t ▁appearance ▁of ▁a ▁sp ont aneous ▁w illed ▁movement . ▁Using ▁functional ▁magnetic ▁reson ance ▁imag ing ▁with ▁special ized ▁mult ivari ate ▁anal ys es ▁to ▁study ▁the ▁temporal ▁dimension ▁in ▁the ▁activation ▁of ▁the ▁cort ical ▁network ▁associated ▁with ▁volunt ary ▁movement ▁in ▁human ▁subjects , ▁an ▁anterior - to - post er ior ▁sequ ential ▁activation ▁process ▁beginning ▁in ▁the ▁supp lement ary ▁motor ▁area ▁on ▁the ▁med ial ▁surface ▁of ▁the ▁front al ▁lo be ▁and ▁progress ing ▁to ▁the ▁primary ▁motor ▁cor tex ▁and ▁then ▁to ▁par iet al ▁cor tex ▁has ▁been ▁observed . ▁The ▁sense ▁of ▁ag ency ▁thus ▁appears ▁to ▁normally ▁emer ge ▁in ▁conj unction ▁with ▁this ▁order ly ▁sequ ential ▁network ▁activation ▁incorpor ating ▁prem ot or ▁association ▁cort ices ▁together ▁with ▁primary ▁motor ▁cor tex . ▁In ▁particular , ▁the ▁supp lement ary ▁motor ▁complex ▁on ▁the ▁med ial ▁surface ▁of ▁the ▁front al ▁lo be ▁appears ▁to ▁activ ate ▁prior ▁to ▁primary ▁motor ▁cor tex ▁pres umably ▁in ▁associated ▁with ▁a ▁prepar atory ▁pre - mov ement ▁process . ▁In ▁a ▁recent ▁study ▁using ▁functional ▁magnetic ▁reson ance ▁imag ing , ▁al ien ▁movements ▁were ▁character ized ▁by ▁a ▁relatively ▁isolated ▁activation ▁of ▁the ▁primary ▁motor