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Scalp distribution of human frequency-following responses to pitch contours in mandarin tones

Scalp distribution of human frequency-following responses to pitch contours in mandarin tones. Jiong Hu Fall 2008. Introduction -- FFR. A type of sustained brainstem neural activity that reflects the potentials integrated over a population of neural elements

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Scalp distribution of human frequency-following responses to pitch contours in mandarin tones

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  1. Scalp distribution of human frequency-following responses to pitch contours in mandarin tones Jiong Hu Fall 2008

  2. Introduction -- FFR • A type of sustained brainstem neural activity that reflects the potentials integrated over a population of neural elements • Has periodic peaks with intervals that correspond to the periodicity of the stimulus token. • Reveals the phase-locking activity of a population of neural elements that is to the individual cycles of the stimulus waveform and the envelope of periodic stimuli

  3. Introduction -- FFR • Carry information about certain steady-state and time-variant acoustic features of speech sounds • Preserve information about the spectra and pitch of speech sounds • Thus, speech stimuli have been used to study the response characteristics of the FFR

  4. Introduction -- FFR • Besides those studies in FFR to neural representations of both steady-state and time-variant stimuli, voice pitch had undergone substantial researches recently • The human FFR representation of pitch contours (pitch contour following response, PCFR)

  5. Introduction -- PCFR Why Chinese Tones? • Lexical tones have harmonics and pitch trajectories that lie within the range of easily recordable PCFRs • Different directional rising or falling of the contours of those lexical tones permits researchers the possibility of examining complex contours and directional changes in pitch • Those syllables allow people to evaluate the encoding of spectral components as well as voice pitch that are associated with vowels and lexical tones

  6. Introduction -- PCFR Recording Montage • To date, all of the previous studies on human PCFR used only one channel recording • Multiple recording montages were used by previous researchers

  7. Introduction -- PCFR Recording Montage (Inverting - NonInverting - Gnd) • Fz - C7 - Fpz (Krishnan et al., 2002; Krishnan et al., 2004; Krishnan et al., 2005) • Fz - ipsimastoid - Fpz/Fz - ipsimastoid – contramastoid (Swaminathan et al., 2008) • Cz - ipsilateral earlobe - Fpz (Krista et al., 2005) • Cz - posterior midline of the neck - collar bone (Dajani et al., 2005)

  8. Introduction -- PCFR What about the distribution on human scalp? • There are no studies aimed to examine the distribution • The best location to record PCFR? • Where is the “hot spot” on its scalp topography?

  9. What is the scalp distribution of PCFRs in response to Mandarin tones? Research Question

  10. Hypotheses • PCFR has a typical response onset latency of about 6 ms • Phase-locked neural activity primarily arises from neural elements deep inside the brain • Homogeneousdistribution on the scalp ? • Small magnitude differences between recording locations? • A unique pattern on the scalp for acoustically evoked ABR. (Starr et al., 1982; Norrix et al., 1996)

  11. Hypotheses • The scalp distribution of the PCFR will be inhomogeneous with a specific pattern. • The PCFR scalp topography will have the largest response amplitudes located at the temporal area contralateral to the stimulation site.

  12. Specific Aims • To quantify and investigate the topographical distribution of the PCFRs on the scalp. • To determine the most promising location and recording montage to mearsure the Mandarin-tone elicited PCFRs.

  13. Methodology-- Subjects • Twelve native speakers of Mandarin Chinese, ranging in age from 20 to 30 years • Hearing threshold greater than 20 dB HL for octave frequencies between 250 and 8000 Hz • Eyes closed and recline on a comfortable chair in an acoustically and electrically treated sound booth

  14. Methodology-- Stimulus Presentation • A set of monosyllabic Mandarin Chinese syllables will be prepared to contrast the four lexical tones: yi1, yi2, yi3, yi4 • Recorded by a native Mandarin Chinese male speaker, with a sampling rate of 40000 samples/sec • Duration of 250 ms with a rising and falling time of 10 ms. The inter-stimulus-interval will be set to 50 ms.

  15. Methodology-- Stimulus Presentation • LabView software written in National Instrument, delivers a trigger pulse synchronized to the onset of each stimulus token • PCI 6221 Input-output card, sampling rate of 40 kHz • Wavetek low-pass filter, TDT PA4, TDT HB6 • Custom-built electromagnetically-shielded insert earphone (Etymotics, ER-3A) • Presented monaurally to the right ear at 55 dB SPL • Two trials of 1100 repetitions for each token

  16. Methodology-- Recording System • Fourteen electrodes will be placed on the scalp based on the modified international 10-20 recording system • Cz, Fz, C3, C4, T3, T4, F3, F4, P3, P4, O1, O2, M1, M2

  17. Methodology-- Recording System • Mid-place between Cz and Cpz serves as non-inverting • low-forehead (Fpz) serves as the Ground • impedances will be maintained below • Amplified through NeuroScan SynAmp2 (24 bit resolution, least significant bit: 0.15 nV) • Recorded using the NeruoScan ACQUIRE 4.3 software, bandpass filtered at 0.05–3500 Hz (6 dB/octave)

  18. Methodology-- Data Analysis • MatLab (2007b) and EEGLab (6.0.1b) • 100-3000 Hz band-pass filter; Segmented 0 to 30 ms • Artifact rejection criteria: • After averaging, carry out a periodicity detection short-term autocorrelation algorithm (Boersma, 1993) on both the stimulus and recordings • Find the major maxima in the autocorrelation function of both the stimulus and response, calculate the corresponding pitch strength • Determine the relative pitch strength between them • Plot a relative pitch strength (PCFR topography) on the scalp

  19. Preliminary Examination • Figure 1: Spectrogram of the stimulus and response

  20. Preliminary Examination • Figure 2: Autocorrelation function, Autocorrelogram, Spectrogram and Power spectral density of the response.

  21. Reference • Boersma P: Accurate short-term analysis of the fundamental frequency and the harmonics-to-noise ratio of a sampled sound. Proc Inst Phon Sci 1993;17:97-110. • Cariani PA, Delgutte B: Neural correlates of the pitch of complex tones: I. Pitch and pitch salience. J Neurophysiol 1996; 76:1698-1716. • Greenberg S, Marsh JT, Brown WS, Smith JC: Neural temporal coding of low pitch: I. Human frequency-following responses to complex tones. Hear Res 1987; 25:91-114. • Dajani HR, Purcell D, Wong W, Kunov H, Picton TW: Recording human evoked potentials that follow the pitch contour of a natural vowel. IEEE Trans Biomed Eng 2005;52:1614-1618 • Johnson KL, Nicol TG., Kraus N: Brain Stem Response to Speech: A Biological Marker of Auditory Processing. Ear & Hearing 2005;26(5):424-434. • Krishanan A: Human frequency-following response to two-tone approximations of steady-state vowels. Audiol Neurootol 1999; 4:95-103. • Krishnan A: Human frequency-following responses: Representation of steady-state synthetic vowels. Hear Res 2002; 166(1-2): 192-201 • Krishnan A, Xu Y, Gandour JT, Cariani PA: Human frequency-following responses: Representation of pitch contours in Chinese tones. Hear Res 2004; 189 (1-2):1-12. • Krishnan A, Xu Y, Gandour JT, Cariani P: Encoding of pitch in the human brainstem is sensitive to language experience. Cogn Brain Res 2005;25:161-168.

  22. Reference • Marsh JT, Brown WS, Smith JC: Differential brainstem pathways for the conduction of auditory frequency-following responses. Electroencephalogr Clin Neurophysiol 1973;36:415-424 • Moushegian G., Rupert AL, Stillman RD: Scalp recorded early responses in man to frequencies in the speech range. Electroencephalogr Clin Neurophysiol 1973;35: 665-667. • Plyer PN, Ananthanarayan AK: Human frequency following Responses: Representation of second formant transitions in normal-hearing and hearing-impaired listeners. J Am Acad Audiol 2001;12: 423-533. • Norrix LW, Glattke TJ: Multichannel waveforms and topographic mapping of the auditory brainstem response under common stimulus and recording conditions. J Commun Disord 1996; 29(3):157-82. • Starr A, Achor J: Auditory brain stem responses in neurological disease. Arch Neurol 1975;32(11):761–768. • Swaminathan J, Krishnan A, Gandour JT: Pitch encoding in speech and nonspeech contexts in the human auditory brainstem. Neuroreport 2008;19(11):1163-1167

  23. Thank you

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