Contains report on one research project.National Institutes of Health (Grant 5 ROl NB-04985-05)U.S. Navy Office of Naval Research (Grant Nonr(G)-00063-65

Douglass, E.

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XVIII. NEUROPHYSIOLOGYAcademic and Research StaffDr. W. S. McCullochProf. J. Y. LettvinProf. M. BlumProf. J. E. BrownProf. B. PomeranzDr.Dr.Dr.Dr.Dr.Dr.T. O. BinfordS-H. ChungE. DouglassDora Jassik- GerschenfeldK. KornackerA. NatapoffT. E. BurkeB. HowlandDiane MajorW. H. PittsJ. R. SeitzGraduate StudentsR. J. BobrowR. E. GreenblattC. D. JonesJ. E. LismanM. LurieK. J. MullerG. P. NelsonJ. F. NolteS. A. RaymondJ. I. SimpsonA. CORTICAL ACTIVITY PRECEDING SPEECHIn 1966, Gilden, Vaughan, and Costal reported time-locked cortical activity pre-ceding foot dorsiflexion and fist clenching. In 1967, Ertl and Schafer 2 corroboratedthese findings but also demonstrated nonrandom cerebral activity preceding speech. InEEG: F7-T5 (10-20 system)J voice activityI I I125 0 TIME (msec) -500Fig. XVIII-1. Average of 100 EEG, EMG, and voice-activity samples precedingand 125 msec following spoken onset of letter "T". Similaritybetween summated EEG and EMG waveforms demonstrates low-frequency myogenic contamination of cortical activity precedingvoice onset indicated by arrow.This work was supported in part by the National Institutes of Health (Grant5 ROl NB-04985-05) and in part by the U.S. Navy Office of Naval Research (GrantNonr(G)- 00063-65).QPR No. 91 251(XVIII. NEUROPHYSIOLOGY)1968, the present writer criticized the study for adopting the criterion of phonation orvocalization as being the true initiation of speech because most speech sounds are, infact, preceded by lip or labial preformation. In collaboration with Ertl and under theguidance of W. S. McCulloch, a series of experiments were performed, and it wasdemonstrated that potentials of myogenic origin invaded the EEG recordings. Conse-quently, an erratum has been submitted for publication by Ertl and Schafer. 3 See alsoFig. XVIII- 1.We do not feel that our study has disproved the existence of cerebral componentsprior to speech. As a matter of fact, it seems logical to assume that such phenomenamust exist.In view of the foregoing, it appears necessary to devise a new experimental designthat would make it possible to eliminate such artefact problems because it is clear thatthe sequencing of neural events occurs at the same time as the muscle activity precedingthe sound of human speech. Previous research by the writer 4 ' 5 in the field of speechand language pathology seems to provide a methodology whereby EEG activity precedinglanguage expression can be studied without contamination from the muscles of speechproximal to the scalp. Such investigations are now in progress and a report of findingswill be submitted as soon as possible.E. DouglassReferences1. L. Gilden, H. G. Vaughan, and L. B. Costa, "Summated Human EEG Potentialswith Voluntary Movements," EEG Clin. Neurophysiol. 20, 433 (1966).2. J. P. Ertl and E. W. P. Schafer, "Cortical Activity Preceding Speech," Life Sci. 6,473-479 (1967).3. J. P. Ertl and E. W. P. Schafer, "Cortical Activity Preceding Speech," in ErratumLife Sci., Vol. 6, pp. 473-479, 1967 (submitted for publication). The text readsas follows:In the course of continued research on cortical activity preceding speech itwas noted that low frequency myogenic or movement artefacts originating fromupper lip musculature contaminated the EEG preceding speech (Fig. 1). Ourearlier findings in which time locked cortical activity preceding speech wasidentified are therefore equivocal. The prediction that specific changes in theelectrical activity of the human brain must precede speech remains unchanged.We have continued to search for this phenomenon by examining the region pre-ceding the earliest onset of EMG activity and by attempting to instrumentallyremove the contributions of EMG from the EEG.4. E. Douglass and J. C. Richardson, "Aphasia in a Congenital Deaf Mute," Brain,Vol. 82, Part 1, pp. 68-80, 1959.5. E. Douglass, "The Development of Stuttering and Its Diagnosis," Can. Med. J. 71,366-371 (1954).QPR No. 91 252

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