 overt speech – is associated with a precise, content-specific efference copy, as opposed to a generic and non-specific prediction. Taken together, our results provide support for the contention that inner speech is a special case of overt speech, which does not have an associated motor act. The notion that inner speech generates an IFM in the absence of an overt motor act has been hypothesized previously across several different literatures (Jones and Fernyhough, 2007; Feinberg, 1978; Scott, 2013; Guenther and Hickok, 2015; Ford et al., 2001b; Sams et al., 2005; Kauramäki et al., 2010). However, this hypothesis has been notoriously difficult to test empirically, due to the covert nature of inner speech. Ford et al., (Ford and Mathalon, 2004) played participants repeated sentences over 30 s and asked them to reproduce the same sentences in inner speech. Ford et al., found that the sentences elicited a smaller N1-component when participants engaged in inner speech compared to when they did not, consistent with the results of the present study. More recently, Tian and Poeppel (Tian and Poeppel, 2010) used MEG to show that the auditory cortex was activated immediately following production of an inner phoneme in the absence of auditory feedback, which they took as evidence of an inner-speech-initiated efference copy. In a subsequent study, which was a strong influence on our own, Tian and Poeppel (Tian and Poeppel, 2013) asked participants to produce an inner phoneme within a 2.4 s window. This window was followed by an audible phoneme that could either match or mismatch the content of the inner phoneme. The authors found no difference in the amplitude of the M100 between the match and mismatch conditions, inconsistent with the results of the present study. However, given the width of the temporal window in which participants were asked to produce their inner phoneme (2.4 s), the efference copy and auditory feedback would not necessarily be expected to coincide under these conditions, in which case M100-suppression would not be expected to occur. Tian and Poeppel (Tian and Poeppel, 2015) asked participants to signal their production of an inner phoneme via a button-press, and measured the amplitude of the M100 component evoked by a pre-recorded audible phoneme of their own voice which matched the content of the inner phoneme
overt speech – is associated with a precise, content - specific efference transcript, as oppose to a generic and non - specific prediction. Taken together, our result put up support for the contention that inside speech is a special case of overt address, which does not have an associated motor act. The notion that inside speech generates an IFM in the absence of an overt motor act has been hypothesized previously across several unlike literatures (Jones and Fernyhough, 2007; Feinberg, 1978; Scott, 2013; Guenther and Hickok, 2015; Ford et al. , 2001b; Sams et al. , 2005; Kauramäki et al. , 2010). However, this hypothesis has been notoriously unmanageable to test empirically, due to the covert nature of inside actor's line. Ford et al. , (Ford and Mathalon, 2004) played participants repeated conviction over 30 s and asked them to regurgitate the same conviction in inner actor's line. Ford et al. , found that the sentences elicited a minor N1 - component when participants engaged in inner speech compare to when they did not, consistent with the results of the present study. More recently, Tian and Poeppel (Tian and Poeppel, 2010) used MEG to show that the auditory cortex was activated immediately following production of an inner phoneme in the absence of auditory feedback, which they learn as evidence of an inner - speech - initiate efference transcript. In a subsequent study, which was a strong influence on our own, Tian and Poeppel (Tian and Poeppel, 2013) asked participants to produce an inner phoneme within a 2.4 s window. This windowpane was followed by an audible phoneme that could either match or mismatch the content of the inner phoneme. The authors found no difference in the amplitude of the M100 between the match and mismatch conditions, inconsistent with the results of the present study. However, give the width of the temporal windowpane in which participant were asked to produce their inner phoneme (2.4 s), the efference copy and auditory feedback would not inevitably be expected to coincide under these conditions, in which case M100 - suppression would not be expected to occur. Tian and Poeppel (Tian and Poeppel, 2015) asked participants to bespeak their production of an inside phoneme via a button - press, and measured the amplitude of the M100 component evoked by a pre - recorded audible phoneme of their own articulation which matched the message of the inner phoneme
 ovfrt speech – is associatea with a precisg, xontenv-specifjc efferdnce copy, as opposed to a geierix and non-specific predictiov. Taken tlgether, iur cesults provide support njr tgc conceition that innet speech is d special case ow lvert speech, which does not have an associstfd motor act. Tre npeion nhct inner speech generates an IFJ in tht absence of an ovrrt motor act has been hyplthedized previously afross severql dydferent litefatures (Jones and Fernihough, 2007; Feinberg, 1978; Scott, 2013; Guenthef and Hickok, 2015; Fire eh al., 2001b; Sams xt al., 2005; Kauramäki et al., 2010). Howaver, thos hypothesis mas bxen botoriously difficult to test empiricaljy, due to tke covert nature of ibnwr spgech. Xord wt xl., (Rocd znd Mahhamon, 2004) playes participabts repeated sentenvef over 30 s and zsked ehqm to reproduce the same sentences in itned speech. Ford et al., foubd that the sentences elicited a smaller N1-component when participants engaged it innxr sptegm coopaged to when they did not, consistent with the wssilns of the present study. More rfcrgtly, Tian and Poeppzm (Fian and Poeppel, 2010) ksed MED to whow that the auditory cortex was activared immediatvly dollowing productiln of an inuer phpneme in the absence of audicory fsedback, whifh they tkuk as evidence ow ak itner-speech-initiated efferegce copy. Mn a xubsequdnt xtudy, rhich was w strong influence on oug own, Than and Pofppel (Tian and Poeppel, 2013) asked pecticipants to psodlce an inuer phpneme within w 2.4 s window. Thns windoc was wollowed bj an audiule phoneme ehat could eidjer match or mismatcr thw cobtent ow the inner phomeme. The cbthors foynd no difference ln thg zmplitude of thz N100 between the mstcf agd mmsmatsv conditions, incunskxtent with the rcsuuts pf the present study. Howsver, given the widyh of the jemporal rindow in whivh participants wege asned to ptodoce their inner phoneme (2.4 s), the sfference coiy and auditowy fcedbwck would uot necessarily be expected to coincide nnder these conditions, un which case M100-supptesxion would iot be expected to occur. Tian and Pieppel (Tian and Ppeppel, 2015) asked particilants do sihnal their production of an inner phoneme via a button-press, and measured rhe am'lytude of ths M100 vompoteut zvoked fy a 're-recorded audibke phoneme of their own voice wiich matchad the content of the inner phpndme
overt speech – is associated with a efference as opposed a generic and results support for the that inner speech a special case of overt speech, does not have an associated motor act. The notion that inner speech generates IFM in the absence of an overt motor act has been hypothesized previously several literatures and 2007; Feinberg, 1978; Scott, 2013; Guenther and Hickok, 2015; Ford et al., 2001b; Sams et al., Kauramäki et al., 2010). However, this hypothesis has notoriously difficult to test due to the covert nature inner Ford et (Ford Mathalon, played participants repeated over 30 s and asked them to reproduce the same sentences in inner speech. Ford et al., that the a smaller when engaged inner speech compared they did not, consistent with the present study. More recently, Tian and Poeppel (Tian Poeppel, 2010) MEG to show that the auditory was activated immediately following production of an inner in the absence of auditory feedback, which they took as evidence of an inner-speech-initiated efference a subsequent study, which a strong influence our Tian Poeppel and Poeppel, asked participants to produce an inner phoneme within a 2.4 s This window was followed by an audible phoneme that could or the content of inner phoneme. The authors no in the amplitude of between match inconsistent the of the present study. given the width of the window in which participants inner phoneme (2.4 s), the efference copy and feedback would not necessarily be expected to under these conditions, in which case M100-suppression would not be expected to Tian and and Poeppel, 2015) asked participants to signal their of an inner phoneme a button-press, and measured the amplitude of the M100 evoked a pre-recorded phoneme of their voice which matched content of the
 overt speech – is associated wiTh a precise, ConteNt-sPecIfIc efFereNce copy, as opposED to a Generic and non-specific pRedicTiON. TakEN tOgethEr, our reSUlTS ProViDe SupPoRT fOr the ConTention That inner sPeeCh Is a special caSE oF overt speeCh, wHich does not hAve An assoCiAteD Motor Act. the noTion thAT inner Speech genErATes an Ifm in the aBSEnCe of An overt motor act haS BeEN hypothesized pReviouSlY AcROSs sEveRal differeNt LiterATures (JoNEs AND ferNYhough, 2007; FeinberG, 1978; Scott, 2013; GuentHEr aNd HickOk, 2015; forD Et al., 2001b; SAms et Al., 2005; kAurAmäki et al., 2010). HoWeveR, this hypoThesis HAs been nOToriousLy diffIcuLt tO tesT EmPiRicAlLY, duE To The COveRt nature Of InNer spEech. fORD Et al., (forD and mathaLon, 2004) played partIciPantS RepEated SenteNces OvEr 30 s anD asked Them tO rEproduce the same SentEnces in inNer SpEecH. FOrd et AL., found ThaT thE sentenCes elicITed A sMALLeR N1-component when parTiCIPaNts engagEd in inNEr SpEEch compaReD to When THEy did Not, cONsIstent wiTh the rESuLtS of the pReSent stUdY. MoRe rEcentLY, TiaN and PoEppel (TiaN and POEppel, 2010) used MEG to SHow that the audIToRY CoRTex wAs aCtivated immEdiaTEly fOlloWInG prODuctiOn of aN iNNeR Phoneme in the absence Of AuditoRy feeDback, which theY took as eviDENCe of an inNer-sPEeCH-initiated effeRence Copy. In a subSEquent stUdy, whIch was a sTrong inflUENce on our Own, tiaN anD PoEPPeL (Tian and PoeppEL, 2013) AskeD pArticipAntS to prodUce An iNneR phOnEme within A 2.4 s window. thIs WiNdOw wAs folLOwed by an AuDibLe PhoNeme tHAt coulD eithEr maTcH oR MisMatch thE CoNTEnt oF tHe InneR phOnEme. ThE autHOrs Found no DifferencE in THe amPlItUde of thE M100 between the mAtCh and mismaTcH coNditioNS, InconsisTent with the results of the PResent sTudY. HoweVer, gIven the wiDth Of the tEmpORal winDow in wHich pArTicIPAnts wERE aSkeD tO produce thEIR inNer phOnEme (2.4 s), The effeRence copy and auditoRY feEdback would noT neCessARIlY be EXpECteD tO CoiNCIde under these coNditions, in WhICh Case M100-supprESsiOn Would noT be expeCted tO Occur. TiAn and PoepPel (Tian anD POeppEL, 2015) AskEd participAnts to siGnal their PRoducTIoN of an InnEr phonEmE viA a butTon-preSS, anD measUred thE aMplituDe of tHe m100 componeNt evoked by a pre-recorded aUdible PhoneMe oF their own VoiCE whIch matcheD the Content of tHe iNneR phonEme
 overt speech – is associa ted with a  prec ise , c on tent -spe cific efferenc e  cop y, as opposed to a gen erican d  non - sp ecifi c predi c ti o n . T ak en  to ge t he r, ou r r esultsprovide su ppo rt  for the con t en tion thatinn er speech is  aspecia lcas e  of o ver t spe ech, w h ich do es not ha ve an ass o ciatedm o to r ac t. The notion tha t  i n ner speech gen erates  a n  I F M  in  th e absenceof  an o v ert mot o ra c t  ha s  been hypothe sized previ o usl y acro ss  se v eral d iffer en t  li teratures ( Jone s and Fer nyhoug h , 2007; Feinber g, 197 8;Sco tt,2 01 3;  Gu en t her an d H i cko k, 2015;  F or d etal., 2 0 0 1b;Sam s et  al.,  2005; Kauram äki  eta l.,  2010 ). Ho weve r,  this  hypot hesis  h as been notorio usly  difficul t t otes tempir i cally,  du e t o the c overt n a tur eo f in ner speech. Ford e ta l .,  (Ford a nd Mat h al on ,  2004) p la yed  par t i cipan ts r e pe ated sen tences ov er  30 s a nd  asked  t hem  to  repr o duce  the s ame sent ences in inner speec h . Ford et al. ,  f o u nd that  th e sentences  eli c ited  a s m al ler N1-co mpone nt wh e n participants enga ge d in i nnerspeech compar ed to when t h ey did n ot,c on s istent with th e res ults of th e  present  stud y. Morerecently, T ian andPoe ppe l ( Tia n an d Poeppel, 20 1 0 ) us ed  MEG to  sh ow that  th e a udi tor ycortex wa s activa te dim me dia telyf ollowing  p rod uc tio n ofa n inne r pho neme  i nt heabsence of a udit or yfeed bac k,  whic h th e y t ook asevidenceofa n in ne r- speech- initiated eff er ence copy.  I n a  subse q u ent stud y, which was a strong i n fluence  on  ourown,  Tian and  Po eppel(Ti a n andPoeppe l, 20 13 ) a s k ed pa r t ic ipa nt s to produ c e  an  inne rphon eme wit hin a 2.4 s window .  Th is window was  fo llow e d  b y a n  a u dib le pho n e me that could e ither matc ho rmismatch t h e c on tent of  the in ner p h oneme.The autho rs foundno  dif f e ren ce in theamplitud e of theM 100 b e tw een t hematchan d m ismat ch con d iti ons,incons is tent w ith t he  results  of the present study.Howeve r, gi ven  the widt h o f  th e tempora l wi ndow in wh ich  pa rtici pan t s wer e as k ed  to produ ce t h eir inner ph one m e  ( 2.4 s), the e f fer encecop y  and a udit ory feedback woul d  not necessari ly b e exp ect e d to  c oincide underthe se c ondition s,  in which c ase M100 -s u ppres sion w ould n ot be e x p ec t ed tooccu r.Tian andPoe pp e l (Tian  a nd Poeppe l, 2 01 5) ask ed par t icip a n ts to signal the ir pr o d uctio n  of  an i nn er phon e me v ia a butto n-press, an d meas ured  theamplitu de  of th e M 10 0 componen t  evoked b y a p re-reco rd ed a udi ble ph onem e of th eirow n v oice whic h ma t ch ed the  con tentof  the  inner ph o neme
 overt_speech –_is associated with a_precise, content-specific_efference_copy, as_opposed_to a generic_and non-specific prediction._Taken together, our results_provide support for_the_contention that inner speech is a special case of overt speech, which does not_have_an associated_motor_act._The notion that inner speech_generates an IFM in the_absence of_an overt motor act has been hypothesized previously_across_several different literatures_(Jones and Fernyhough, 2007; Feinberg, 1978; Scott, 2013; Guenther_and Hickok, 2015; Ford et al.,_2001b; Sams et_al.,_2005;_Kauramäki et al., 2010)._However, this hypothesis has been notoriously_difficult to test empirically, due to_the covert nature of inner speech. Ford_et al., (Ford and Mathalon, 2004)_played participants repeated sentences over_30 s_and asked them to reproduce_the same sentences_in inner_speech. Ford et_al., found that the sentences elicited_a smaller N1-component_when participants engaged in inner speech_compared_to when they_did_not,_consistent with_the results of_the_present study._More_recently, Tian and Poeppel (Tian and_Poeppel,_2010) used MEG to show that the_auditory cortex was activated_immediately_following production of an_inner phoneme in the absence_of auditory feedback, which they took_as evidence_of an_inner-speech-initiated efference copy. In a subsequent study, which was a strong_influence on our own, Tian and_Poeppel (Tian and Poeppel,_2013) asked_participants_to produce an_inner_phoneme within_a 2.4 s window. This window was_followed by_an audible phoneme that could either_match or mismatch the_content_of the inner phoneme. The authors_found no difference in the amplitude_of the M100 between the_match_and_mismatch conditions, inconsistent with the_results of the present study. However,_given the width_of the temporal window in which participants_were_asked to produce their inner phoneme_(2.4_s), the efference copy and auditory_feedback_would_not necessarily be expected to_coincide under these conditions, in which_case M100-suppression would not be expected to occur. Tian_and Poeppel (Tian_and Poeppel, 2015) asked participants_to_signal_their production of an inner phoneme via a button-press, and_measured the_amplitude of the_M100 component evoked by a pre-recorded audible phoneme of their_own voice which matched the content of_the inner phoneme