Can. J. Physiol. Pharmacol. Downloaded from www.nrcresearchpress.com by LEHIGH UNIVERSITY on 12/13/14 For personal use only.
The electro~nyugraphicresponse to sudden sbetches of limb muscles in normal lluman subjects1
Keceivetf May '39, 1978
O'R~AHN, sf. n., %%LAIR,R. D. 6.. and ~ ~ I I ; W P H J.Y , T'. 1978. The electronlysgraphic response to suddear atretches of iinah ~niisclesin raornrmal human ~ul>jccfs.Can. J. Physiol. PharmacoI. 56, 73 1-776. The electrom~~ogr:~p%-iic (EMG) actial~tyfollowing a sudderm stretch ~tg?pliedto wrist flexor or extensor nmtascles wa4 i~~vcstigated 114irlg a method which enableti the indikicl~aal r e c r ~ds~ and cumulative se\alIhs o f 30 8s-ials to be obwr ved simrallaneoiasly. The rcsa~lts showed that in each case the spinal reflex F M G burst \;\/as follllowcd by one or t h o additional re1lc.x bursts. 'H'he hecclnd of thew latter lstmr\ts. M hen present, o t c ~ ~ r r eilld one of t\vo distinct latearcy ranges. Thus, threc clistinct Iateacy range5 were observed for rcigcx Iiiarsts following the \pinal reflex burst. A possible cxpTkznatiasn for these rc\ults is that there ai-e three distir~ctlong-loop rcflexb.5, one or two of which may be a c t h e lollohing a muscle 5tretc8-1. 7'Re present les~altstfo not distingujhh whether any or all of these lungloop r-eflcxes arc segmental or sup1aspinal in 631 igin. Q'16141~. 34. D., BLAIR, K. D. G., et M U R P F ~ Y 5 ., %'. 1978. The electrsmyogra1s8nic response to wdden stretches of limb mugcles in ilol-rn:l%hun-aun sr~lpjecls.Can. .I. PBlysioI. Phasmacol. 56, 77 1--776,. On 3 etudi@I'actikilO I:MG qua suit un brusque ktirernent des muscles flichisseurs ou extensews clia poigraet, en u t i l i ~ i ~ niinz t rn6tkodc q ~ permet ~ i d'observer sinlultan61raent des enrepist~enaetlts,individuellement ou de f;lc;csn curna~lative;ces emrcgistrements portent sur 30 essais. 1x5 aisultatb obfcn11~rnontreilt que I'EMG 1an6drallaire riflexe est suivi d a m cllaque cas cl'iine o ~ aclei~xsal\rcs i~dditii~nnelle~. I o r s q ~ i eprisente, la 5cconde de ces salves surclent avcc une Iiatence q ~ upeanl avois- deiax durCes distinctes. On a ainsi observC trois d'iiries distinctes de latente cn ct: qisi concerne Ies salves ns6dnllaires rCflexes. Unc exp1ic:ition possible h eel ri\nltats est qra'il existe trois longues lloa~clesrc3exes d~stmctes.dont une O L cieilx ~ peilvent strc actives en rkponse ri un etirement rnuscular're, kes risultats pr2serrtCs ne peimnettent pa4 dc dssceraer c i l'unc ou la totaliti dc ces b o ~ ~ c l e s rkflexes est d'origirac srgmentaire ou s~rpraspinale, ['Tr:ad~aitpar le journal]
by the authors cited above, and by others, that the h4L EMG responses may be caused by supraspir~a'l reflex loesps. Tatton arsd Lee ( 1975) have shown, using averaged data. that two distinct bursts of activity are somelimes fourad in this hnlL region. Thev used the ntrtation M2 and M3 tea denote these bursts, and h l l to dcraote thc earlier spinal reflex burst. However, an averaging process can sometimes prtsdsace rnsisleading results by masking the detail observed i~m individual responses or by producing an averaged respome which could never A u n ~ ~ v ~ ~ r r o iE111G. f i s : electromyograph ( i ) ~: SL,, short occur ira at1 i~ldividualrecord. Therefore we thought latency; MI-. anediun~ Iatenc) ; I,L, long latcrlcy; I- .C,M.. i t wtruld be of interest to investigate the reflcx EMG flexor carpi radialis: E.C.R.L.. extensor can-pi radialis Ionpi~s; responses on a trial-to-trial basis. .PgTP, rninirntmrn timc interval.
Introduction A number sf investigators have reportscl that the E M 6 response to a sudden stretch of a limb muscle contains component% which appear. to be meithen. spinal nor purely vsluntrrrg; (Harnl~~ds~ad 1956; MelJones and Watt 1971 ; Tattsra arad Lee 1945). These colaaponents will bc lcrrrned 'ML E M G responses,' to distinguish them fre~nrthe SL EhIG comptrnents which are clearly spiraal, and from the LZ.,, p~rrelq-voluntary components. It Isas heen suggested
'Supported by the Medical Research Ce~uncilof Canada. the Multiple S~lerosisSociety. and the Biskell Foaindatiom. 'Presently with the Department of Research. RehabilitaI-Eexit~nand extension of the hand about the wrist were tion Institute of Montreal, Moratl-eal, P.Q., Canada H3S 2J4. "eprint requests should be Sent to Prof. J. T. hfiarphgi, chosen as thc nnovements to be used in this B'nve~tigation. Department of PhysioIogy, C~ni\~ersity of Toronto, Torontc~. lland mucement(; rare extremely important in primates and nman, asad a large portion sf the brain is devoted to thcir Ont., Canada MSS ZA8.
Can. J. Physiol. Pharmacol. Downloaded from www.nrcresearchpress.com by LEHIGH UNIVERSITY on 12/13/14 For personal use only.
CAN. J. PHYSIOL. PHARMACOL. B'OL. 56, 1978
FIG^ 1. Aniplitude discrimination of the full-wave rectified and integrated EMC's wave form from F.C.R. nauscle. A stretch was applied to the rnuscle at tinae = 0.
control. Tn addition. analsgo~asexperiments o n primates, using wrist movement, are being conducted in parallel in our laboratories. L%'rist flexor or exfenmr muscles were stretched by applying step torques to the subjects' wri4ts using a specially designee! nrn~~nipulandu~ra incorporating a torque motor (rise time tc? araaximun~torque 3 ms). The occurrcnces s f the torques were I-andom with respect to both time and direction (flexion or extension). Prior to and during the torque distrarbrtnses, the subjects were given visuai feedback of hand position by means of a small circle displayed on a teievision monitor. Flexic~nor extension of the hand about the wrist caused the circle to move horizontally on the screen. A vertical line also appeared on the screen, and the ~ubjectswere instructed to saqxrin-apose the circle on the line. and lo return the circle to the line if it was displaced B7y the torque disturbance. The step torqrles were suddenly released either I .5, 2, or 3.5 s following onset, the specific times being chosen randomly. The torque release resulted in a sudden stretch being applied to the antagonist mnscie, thus giving additional data on the stretch reflex. In every case. the agonist and antagonist muscles were relaxed prior to the application of a stretch. This was achieved by asking the subjects to relax and by giving them zero torque prior to the onset of stretch (which avoided co-contraction). The antagonist rrlalscles were relaxed prior to the release of torque due to reciprocal inhibition as a result of the contraction of the agonist n-auscles. It was necessary to use zero initial torqrae loading of the agonists in order to avoid fatigue of individual motor units, and because initial loading prevents the detection of the SB, response. The IEMG activity was measured from F.C.K. and E.C.R.L. rntascles. Bipolar electrodes were used consisting of two ~ t r a n d sof 'Karn-aa' alloy wire 475% Ni, 20% Cr, 2.596 Fe. 2.5% A l ) , 50 ,urn in dianneter. inserted separately 1 cm apart axially along the nauscle. The EM@ signals were ful8-wave rectified and integrated over successive 1.25-111s irmtervds. The wave form of these integrals, ~ l h e nplotted, gave a slightly smoothed version of the original full-wave rectified IEW.I[G. The times of occalrrence of the EMG br~rstswere con-
The electro~nyugraphicresponse to sudden sbetches of limb muscles in normal lluman subjects1
Keceivetf May '39, 1978
O'R~AHN, sf. n., %%LAIR,R. D. 6.. and ~ ~ I I ; W P H J.Y , T'. 1978. The electronlysgraphic response to suddear atretches of iinah ~niisclesin raornrmal human ~ul>jccfs.Can. J. Physiol. PharmacoI. 56, 73 1-776. The electrom~~ogr:~p%-iic (EMG) actial~tyfollowing a sudderm stretch ~tg?pliedto wrist flexor or extensor nmtascles wa4 i~~vcstigated 114irlg a method which enableti the indikicl~aal r e c r ~ds~ and cumulative se\alIhs o f 30 8s-ials to be obwr ved simrallaneoiasly. The rcsa~lts showed that in each case the spinal reflex F M G burst \;\/as follllowcd by one or t h o additional re1lc.x bursts. 'H'he hecclnd of thew latter lstmr\ts. M hen present, o t c ~ ~ r r eilld one of t\vo distinct latearcy ranges. Thus, threc clistinct Iateacy range5 were observed for rcigcx Iiiarsts following the \pinal reflex burst. A possible cxpTkznatiasn for these rc\ults is that there ai-e three distir~ctlong-loop rcflexb.5, one or two of which may be a c t h e lollohing a muscle 5tretc8-1. 7'Re present les~altstfo not distingujhh whether any or all of these lungloop r-eflcxes arc segmental or sup1aspinal in 631 igin. Q'16141~. 34. D., BLAIR, K. D. G., et M U R P F ~ Y 5 ., %'. 1978. The electrsmyogra1s8nic response to wdden stretches of limb mugcles in ilol-rn:l%hun-aun sr~lpjecls.Can. .I. PBlysioI. Phasmacol. 56, 77 1--776,. On 3 etudi@I'actikilO I:MG qua suit un brusque ktirernent des muscles flichisseurs ou extensews clia poigraet, en u t i l i ~ i ~ niinz t rn6tkodc q ~ permet ~ i d'observer sinlultan61raent des enrepist~enaetlts,individuellement ou de f;lc;csn curna~lative;ces emrcgistrements portent sur 30 essais. 1x5 aisultatb obfcn11~rnontreilt que I'EMG 1an6drallaire riflexe est suivi d a m cllaque cas cl'iine o ~ aclei~xsal\rcs i~dditii~nnelle~. I o r s q ~ i eprisente, la 5cconde de ces salves surclent avcc une Iiatence q ~ upeanl avois- deiax durCes distinctes. On a ainsi observC trois d'iiries distinctes de latente cn ct: qisi concerne Ies salves ns6dnllaires rCflexes. Unc exp1ic:ition possible h eel ri\nltats est qra'il existe trois longues lloa~clesrc3exes d~stmctes.dont une O L cieilx ~ peilvent strc actives en rkponse ri un etirement rnuscular're, kes risultats pr2serrtCs ne peimnettent pa4 dc dssceraer c i l'unc ou la totaliti dc ces b o ~ ~ c l e s rkflexes est d'origirac srgmentaire ou s~rpraspinale, ['Tr:ad~aitpar le journal]
by the authors cited above, and by others, that the h4L EMG responses may be caused by supraspir~a'l reflex loesps. Tatton arsd Lee ( 1975) have shown, using averaged data. that two distinct bursts of activity are somelimes fourad in this hnlL region. Thev used the ntrtation M2 and M3 tea denote these bursts, and h l l to dcraote thc earlier spinal reflex burst. However, an averaging process can sometimes prtsdsace rnsisleading results by masking the detail observed i~m individual responses or by producing an averaged respome which could never A u n ~ ~ v ~ ~ r r o iE111G. f i s : electromyograph ( i ) ~: SL,, short occur ira at1 i~ldividualrecord. Therefore we thought latency; MI-. anediun~ Iatenc) ; I,L, long latcrlcy; I- .C,M.. i t wtruld be of interest to investigate the reflcx EMG flexor carpi radialis: E.C.R.L.. extensor can-pi radialis Ionpi~s; responses on a trial-to-trial basis. .PgTP, rninirntmrn timc interval.
Introduction A number sf investigators have reportscl that the E M 6 response to a sudden stretch of a limb muscle contains component% which appear. to be meithen. spinal nor purely vsluntrrrg; (Harnl~~ds~ad 1956; MelJones and Watt 1971 ; Tattsra arad Lee 1945). These colaaponents will bc lcrrrned 'ML E M G responses,' to distinguish them fre~nrthe SL EhIG comptrnents which are clearly spiraal, and from the LZ.,, p~rrelq-voluntary components. It Isas heen suggested
'Supported by the Medical Research Ce~uncilof Canada. the Multiple S~lerosisSociety. and the Biskell Foaindatiom. 'Presently with the Department of Research. RehabilitaI-Eexit~nand extension of the hand about the wrist were tion Institute of Montreal, Moratl-eal, P.Q., Canada H3S 2J4. "eprint requests should be Sent to Prof. J. T. hfiarphgi, chosen as thc nnovements to be used in this B'nve~tigation. Department of PhysioIogy, C~ni\~ersity of Toronto, Torontc~. lland mucement(; rare extremely important in primates and nman, asad a large portion sf the brain is devoted to thcir Ont., Canada MSS ZA8.
Can. J. Physiol. Pharmacol. Downloaded from www.nrcresearchpress.com by LEHIGH UNIVERSITY on 12/13/14 For personal use only.
CAN. J. PHYSIOL. PHARMACOL. B'OL. 56, 1978
FIG^ 1. Aniplitude discrimination of the full-wave rectified and integrated EMC's wave form from F.C.R. nauscle. A stretch was applied to the rnuscle at tinae = 0.
control. Tn addition. analsgo~asexperiments o n primates, using wrist movement, are being conducted in parallel in our laboratories. L%'rist flexor or exfenmr muscles were stretched by applying step torques to the subjects' wri4ts using a specially designee! nrn~~nipulandu~ra incorporating a torque motor (rise time tc? araaximun~torque 3 ms). The occurrcnces s f the torques were I-andom with respect to both time and direction (flexion or extension). Prior to and during the torque distrarbrtnses, the subjects were given visuai feedback of hand position by means of a small circle displayed on a teievision monitor. Flexic~nor extension of the hand about the wrist caused the circle to move horizontally on the screen. A vertical line also appeared on the screen, and the ~ubjectswere instructed to saqxrin-apose the circle on the line. and lo return the circle to the line if it was displaced B7y the torque disturbance. The step torqrles were suddenly released either I .5, 2, or 3.5 s following onset, the specific times being chosen randomly. The torque release resulted in a sudden stretch being applied to the antagonist mnscie, thus giving additional data on the stretch reflex. In every case. the agonist and antagonist muscles were relaxed prior to the application of a stretch. This was achieved by asking the subjects to relax and by giving them zero torque prior to the onset of stretch (which avoided co-contraction). The antagonist rrlalscles were relaxed prior to the release of torque due to reciprocal inhibition as a result of the contraction of the agonist n-auscles. It was necessary to use zero initial torqrae loading of the agonists in order to avoid fatigue of individual motor units, and because initial loading prevents the detection of the SB, response. The IEMG activity was measured from F.C.K. and E.C.R.L. rntascles. Bipolar electrodes were used consisting of two ~ t r a n d sof 'Karn-aa' alloy wire 475% Ni, 20% Cr, 2.596 Fe. 2.5% A l ) , 50 ,urn in dianneter. inserted separately 1 cm apart axially along the nauscle. The EM@ signals were ful8-wave rectified and integrated over successive 1.25-111s irmtervds. The wave form of these integrals, ~ l h e nplotted, gave a slightly smoothed version of the original full-wave rectified IEW.I[G. The times of occalrrence of the EMG br~rstswere con-
