Investigating the neural correlates of continuous speech computation with frequency-tagged neuroelectric responses

In order to learn an oral language, humans have to discover words from a continuous signal. Streams of artificial monotonous speech can be readily segmented based on the statistical analysis of the syllables' distribution. This parsing is considerably improved when acoustic cues, such as subliminal pauses, are added suggesting that a different mechanism is involved. Here we used a frequency-tagging approach to explore the neural mechanisms underlying word learning while listening to continuous speech. High-density EEG was recorded in adults listening to a concatenation of either random syllables or tri-syllabic artificial words, with or without subliminal pauses added every three syllables. Peaks in the EEG power spectrum at the frequencies of one and three syllables occurrence were used to tag the perception of a monosyllabic or tri-syllabic structure, respectively. Word streams elicited the suppression of a one-syllable frequency peak, steadily present during random streams, suggesting that syllables are no more perceived as isolated segments but bounded to adjacent syllables. Crucially, three-syllable frequency peaks were only observed during word streams with pauses, and were positively correlated to the explicit recall of the detected words. This result shows that pauses facilitate a fast, explicit and successful extraction of words from continuous speech, and that the frequency-tagging approach is a powerful tool to track brain responses to different hierarchical units of the speech structure.

[1]  Ramesh Srinivasan,et al.  MEG phase follows conscious perception during binocular rivalry induced by visual stream segregation. , 2006, Cerebral cortex.

[2]  Thomas E. Nichols,et al.  Nonparametric permutation tests for functional neuroimaging: A primer with examples , 2002, Human brain mapping.

[3]  J. Mehler,et al.  Do infants perceive word boundaries? An empirical study of the bootstrapping of lexical acquisition. , 1994, The Journal of the Acoustical Society of America.

[4]  Lisa D. Sanders,et al.  An ERP study of continuous speech processing. II. Segmentation, semantics, and syntax in non-native speakers. , 2003, Brain research. Cognitive brain research.

[5]  E. Newport,et al.  WORD SEGMENTATION : THE ROLE OF DISTRIBUTIONAL CUES , 1996 .

[6]  Lisa D. Sanders,et al.  An ERP study of continuous speech processing. I. Segmentation, semantics, and syntax in native speakers. , 2003, Brain research. Cognitive brain research.

[7]  Elissa L. Newport,et al.  The Role of Stress and Position in Determining First Words , 1992 .

[8]  J. Mehler,et al.  Phonological phrase boundaries constrain lexical access II. Infant data , 2004 .

[9]  M. Goldsmith,et al.  Statistical Learning by 8-Month-Old Infants , 1996 .

[10]  David B. Pisoni,et al.  CHAPTER 1 – Speech Perception: Research, Theory, and the Principal Issues* , 1986 .

[11]  D P Phillips,et al.  Auditory gap detection, perceptual channels, and temporal resolution in speech perception. , 1999, Journal of the American Academy of Audiology.

[12]  D. Poeppel,et al.  Phase Patterns of Neuronal Responses Reliably Discriminate Speech in Human Auditory Cortex , 2007, Neuron.

[13]  P. Jusczyk,et al.  Clauses are perceptual units for young infants , 1987, Cognition.

[14]  A. Endress,et al.  Rapid learning of syllable classes from a perceptually continuous speech stream , 2007, Cognition.

[15]  Eric Wanner,et al.  Language acquisition: the state of the art , 1982 .

[16]  J. Mehler,et al.  Syllables as units in infant speech perception , 1981 .

[17]  Robert M. Gonyea,et al.  Learning at a Distance : , 2009 .

[18]  J. Hayes.  Cognition and the development of language , 1970 .

[19]  A. Rodríguez-Fornells,et al.  The effects of stress and statistical cues on continuous speech segmentation: An event-related brain potential study , 2006, Brain Research.

[20]  Emmanuel Dupoux,et al.  Expe: An expandable programming language for on-line psychological experiments , 1997 .

[21]  Robert Pilon,et al.  Segmentation of speech in a foreign language , 1981 .

[22]  R. Oostenveld,et al.  Nonparametric statistical testing of EEG- and MEG-data , 2007, Journal of Neuroscience Methods.

[23]  J. Mehler,et al.  Linguistic Constraints on Statistical Computations , 2005, Psychological science.

[24]  Catharine H. Echols,et al.  The perception of rhythmic units in speech by infants and adults. , 1997 .

[25]  T. Picton,et al.  Human auditory steady-state responses: Respuestas auditivas de estado estable en humanos , 2003, International journal of audiology.

[26]  Elissa L. Newport,et al.  Segmenting nonsense: an event-related potential index of perceived onsets in continuous speech , 2002, Nature Neuroscience.

[27]  Eric Wanner,et al.  A technology anthology. Recent writings and remarks on the state of the state-of-the-art. , 1982, Health systems review.

[28]  Marcela Peña.  Rôle du calcul statistique dans l'acquisition du langage , 2002 .

[29]  E. Newport,et al.  Learning at a distance I. Statistical learning of non-adjacent dependencies , 2004, Cognitive Psychology.

[30]  Arnaud Delorme,et al.  EEGLAB: an open source toolbox for analysis of single-trial EEG dynamics including independent component analysis , 2004, Journal of Neuroscience Methods.

[31]  Anne-Catherine Bachoud-Lévi,et al.  Different Neurophysiological Mechanisms Underlying Word and Rule Extraction from Speech , 2007, PloS one.

[32]  J. Mazziotta,et al.  Cracking the Language Code: Neural Mechanisms Underlying Speech Parsing , 2006, The Journal of Neuroscience.

[33]  A. Rodríguez-Fornells,et al.  Beneficial effects of word final stress in segmenting a new language: evidence from ERPs , 2008, BMC Neuroscience.

[34]  Marina Nespor,et al.  An interaction between prosody and statistics in the segmentation of fluent speech , 2007, Cognitive Psychology.

[35]  Sarah C. Creel,et al.  Distant melodies: statistical learning of nonadjacent dependencies in tone sequences. , 2004, Journal of experimental psychology. Learning, memory, and cognition.

[36]  Guillaume P. Dehaene,et al.  Functional segregation of cortical language areas by sentence repetition , 2006, Human brain mapping.

[37]  Richard S. J. Frackowiak,et al.  Endogenous Cortical Rhythms Determine Cerebral Specialization for Speech Perception and Production , 2007, Neuron.

[38]  Ulrich Hans Frauenfelder,et al.  The syllable's role in speech segmentation , 1981 .

[39]  D. P. Russell,et al.  Investigating neural correlates of conscious perception by frequency-tagged neuromagnetic responses. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[40]  Marina Nespor,et al.  Signal-Driven Computations in Speech Processing , 2002, Science.

[41]  D. Abrams,et al.  Right-Hemisphere Auditory Cortex Is Dominant for Coding Syllable Patterns in Speech , 2008, The Journal of Neuroscience.

[42]  A. Woodward,et al.  Perception of acoustic correlates of major phrasal units by young infants , 1992, Cognitive Psychology.

[43]  A. Christophea,et al.  Phonological phrase boundaries constrain lexical access I . Adult data q , 2003 .

[44]  Catharine H. Echols.  A perceptually-based model of children's earliest productions , 1993, Cognition.

[45]  E Ahissar,et al.  Speech comprehension is correlated with temporal response patterns recorded from auditory cortex , 2001, Proceedings of the National Academy of Sciences of the United States of America.