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Christian Lorenzi

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Christian Lorenzi
Christian Lorenzi in 2012
Born (1968-04-15) April 15, 1968 (age 56)
EducationPhD, Université Lyon 2, France, 1995
Scientific career
FieldsAuditory sciences
InstitutionsÉcole Normale Supérieure, Paris, France
Thesis "Codage de la modulation d'amplitude dans le système auditif: expériences psychoacoustiques et modélisation physiologique"  (1995)
Websitelsp.dec.ens.fr/en/member/646/christian-lorenzi

Christian Lorenzi (born April 15, 1968) is Professor of Experimental Psychology at École Normale Supérieure in Paris, France, where he has been Director of the Department of Cognitive Studies and Director of Scientific Studies until.[1] Lorenzi works on auditory perception.

Biography

Lorenzi obtained a PhD in experimental psychology from Université Lyon 2 in 1995[2] for his work on "Codage de la modulation d'amplitude dans le système auditif: expériences psychoacoustiques et modélisation physiologique" (coding of amplitude modulation in the auditory system: psychoacoustical experiments and physiological modelling). He then spent a year as a postdoc at the Applied Psychology Unit in Cambridge, UK, where he worked with Roy D. Patterson on the perception of temporally asymmetric envelopes[3] and click trains.[4] The following year, he moved to the Glasgow branch of the MRC Institute of Hearing Research where he worked with Stuart Gatehouse.[5]

Back in France, he became Lecturer (Maître de Conférences) at the Université Paris Descartes. He obtained his Habilitation à Diriger les Recherches in 2000 and became Professor in 2001.[6] During this period, he is a member of the Laboratoire de Psychologie de la Perception where he worked on the creation of the Équipe Audition which becomes physically located at the ENS.[7] In 2011, his affiliation officially changed to the École Normale Supérieure, where he was Director of Scientific Studies until 2020.

Lorenzi became a fellow of the Acoustical Society of America in 2008.[8]

Research

Sounds such as speech, music and natural soundscapes are decomposed by the peripheral auditory system of humans (the cochlea) into narrow frequency bands. The resulting signals convey information at different time scales to more central auditory structures. A dichotomy between slow "temporal envelope" cues and faster "temporal fine structure" (TFS) cues has been proposed to explore several aspects of auditory perception including speech intelligibility in quiet or against competing sound sources.

Starting from the late nineties, Lorenzi conducted a research program on auditory perception combining signal processing, psychophysical, electrophysiological and computational methods based on this envelope/TFS dichotomy. He examined the role of these two cues in sound discrimination and auditory scene analysis,[9][10] how these cues are processed at each stage of the auditory system, and the effects of peripheral (cochlear)[11] or central damage,[12] development,[13][14] ageing[15] and rehabilitation systems (e.g., hearing aids[16] or cochlear implants[17]) on the perception of these temporal envelope and TFS cues.

His early work on the perception of temporal-envelope information corroborated the existence of tuned (selective) modulation filters at central stages of the human auditory system, consistent with the notion that the auditory system computes some form of modulation spectrum of incoming sounds.[18][19] He then showed that dynamic information in sounds not only is carried by so-called first-order characteristic of sounds (e.g., onset and offset cues, slow amplitude modulations composing the envelope of sounds), but also can be carried by “second-order” characteristics such as variations in the temporal-envelope contrast (modulation depth). His psychophysical conducted on normal-hearing people and patients with cochlear or brain lesions is consistent with the idea that, as in vision, nonlinear mechanisms along the auditory pathway generate an audible distortion component at the 2nd-order AM frequency in the internal modulation spectrum of sounds.[20]

His more recent work on the perception of TFS information suggested that TFS cues convey as much spectro-temporal information as temporal-envelope cues do for complex sounds such as speech.[21] He also showed that TFS cues are less vulnerable than temporal envelope cues when sounds are masked by competing sounds such as noise or presented at high intensities, and may play a role in robust sound coding at the low (brainstem) level.[21][22] His work conducted with people with sensorineural hearing loss and computational models of auditory perception showed how cochlear lesions may alter the neural representation of TFS cues in the early stages of the auditory system, even in regions of the pure-tone audiogram where hearing is clinically considered as normal.[23][24][25][26]

See also

References

  1. ^ "Rencontre avec les directeurs d'études de l'École normale – ENS". www.ens.psl.eu. Retrieved 14 July 2020.
  2. ^ "Atelier National de Reproduction des Thèses". Retrieved 10 March 2018.
  3. ^ Lorenzi, C.; Gallégo, S.; Patterson, R. D. (July 1997). "Discrimination of temporal asymmetry in cochlear implantees". The Journal of the Acoustical Society of America. 102 (1): 482–485. Bibcode:1997ASAJ..102..482L. doi:10.1121/1.419721. ISSN 0001-4966. PMID 9228811.
  4. ^ Tsuzaki, M.; Patterson, R. D.; Lorenzi, C. (1996). "Detecting time and amplitude jitter in a click train". The Journal of the Acoustical Society of America. 100 (4): 2681. Bibcode:1996ASAJ..100.2681T. doi:10.1121/1.416966.
  5. ^ Lorenzi, C.; Gatehouse, S.; Lever, C. (1997). "Sound localization in noise in hearing‐impaired listeners". The Journal of the Acoustical Society of America. 101 (5): 3104–3105. doi:10.1121/1.418860.
  6. ^ "Collège de France" (PDF). Retrieved 10 March 2018.
  7. ^ "Laboratoire de Psychologie de la Perception". Archived from the original on 2006-06-21. Retrieved 2019-07-01.
  8. ^ "Fellows". Acoustical Society of America. Retrieved 10 March 2018.
  9. ^ Varnet, Léo; Ortiz-Barajas, Maria Clemencia; Erra, Ramón Guevara; Gervain, Judit; Lorenzi, Christian (October 2017). "A cross-linguistic study of speech modulation spectra". The Journal of the Acoustical Society of America. 142 (4): 1976. Bibcode:2017ASAJ..142.1976V. doi:10.1121/1.5006179. ISSN 1520-8524. PMID 29092595. S2CID 25269485.
  10. ^ Thoret, Etienne; Varnet, Léo; Boubenec, Yves; Férriere, Régis; Le Tourneau, François-Michel; Krause, Bernie; Lorenzi, Christian (May 2020). "Characterizing amplitude and frequency modulation cues in natural soundscapes: A pilot study on four habitats of a biosphere reserve". The Journal of the Acoustical Society of America. 147 (5): 3260–3274. Bibcode:2020ASAJ..147.3260T. doi:10.1121/10.0001174. ISSN 0001-4966. PMID 32486802. S2CID 218925444.
  11. ^ Füllgrabe, Christian; Meyer, Bernard; Lorenzi, Christian (2003-04-01). "Effect of cochlear damage on the detection of complex temporal envelopes". Hearing Research. 178 (1): 35–43. doi:10.1016/S0378-5955(03)00027-3. ISSN 0378-5955. PMID 12684175. S2CID 40456502.
  12. ^ Lorenzi, Christian; Wable, Jocelyne; Moroni, Christine; Derobert, Christophe; Frachet, Bruno; Belin, Catherine (2000-05-01). "Auditory temporal envelope processing in a patient with left-hemisphere damage". Neurocase. 6 (3): 231–244. doi:10.1080/13554790008402773. ISSN 1355-4794. S2CID 143441282.
  13. ^ Bertoncini, Josiane; Nazzi, Thierry; Cabrera, Laurianne; Lorenzi, Christian (May 2011). "Six-month-old infants discriminate voicing on the basis of temporal envelope cues (L)". Journal of the Acoustical Society of America. 129 (5): 2761–2764. Bibcode:2011ASAJ..129.2761J. doi:10.1121/1.3571424. PMID 21568380. S2CID 25412515.
  14. ^ Cabrera, Laurianne; Varnet, Léo; Buss, Emily; Rosen, Stuart; Lorenzi, Christian (October 2019). "Development of temporal auditory processing in childhood: Changes in efficiency rather than temporal-modulation selectivity". Journal of the Acoustical Society of America. 146 (4): 2415–2429. Bibcode:2019ASAJ..146.2415C. doi:10.1121/1.5128324. PMID 31672005. S2CID 204957873.
  15. ^ Wallaert, Nicolas; Moore, Brian C. J.; Lorenzi, Christian (June 2016). "Comparing the effects of age on amplitude modulation and frequency modulation detection". The Journal of the Acoustical Society of America. 139 (6): 3088. Bibcode:2016ASAJ..139.3088W. doi:10.1121/1.4953019. ISSN 1520-8524. PMID 27369130.
  16. ^ Ives, D. Timothy; Calcus, Axelle; Kalluri, Sridhar; Strelcyk, Olaf; Sheft, Stanley; Lorenzi, Christian (February 2013). "Effects of Noise Reduction on AM and FM Perception". JARO: Journal of the Association for Research in Otolaryngology. 14 (1): 149–157. doi:10.1007/s10162-012-0358-8. ISSN 1525-3961. PMC 3540276. PMID 23180229.
  17. ^ Gnansia, Dan; Lazard, Diane S.; Léger, Agnès C.; Fugain, Claude; Lancelin, Denis; Meyer, Bernard; Lorenzi, Christian (2014-01-01). "Role of slow temporal modulations in speech identification for cochlear implant users". International Journal of Audiology. 53 (1): 48–54. doi:10.3109/14992027.2013.844367. ISSN 1499-2027. PMID 24195655. S2CID 35754090.
  18. ^ Giraud, Anne-Lise; Lorenzi, Christian; Ashburner, John; Wable, Jocelyne; Johnsrude, Ingrid; Frackowiak, Richard; Kleinschmidt, Andreas (September 2000). "Representation of the Temporal Envelope of Sounds in the Human Brain". Journal of Neurophysiology. 84 (3): 1588–1598. doi:10.1152/jn.2000.84.3.1588. PMID 10980029. S2CID 9020690.
  19. ^ Liegeois-Chauvel, C.; Lorenzi, C.; Trébuchon, A.; Régis, J.; Chauvel, P. (28 March 2004). "Temporal Envelope Processing in the Human Left and Right Auditory Cortices". Cerebral Cortex. 14 (7): 731–740. doi:10.1093/cercor/bhh033. PMID 15054052.
  20. ^ Lorenzi, Christian; Soares, Catherine; Vonner, Thomas (August 2001). "Second-order temporal modulation transfer functions". The Journal of the Acoustical Society of America. 110 (2): 1030–1038. Bibcode:2001ASAJ..110.1030L. doi:10.1121/1.1383295. PMID 11519571.
  21. ^ a b Shamma, Shihab; Lorenzi, Christian (May 2013). "On the balance of envelope and temporal fine structure in the encoding of speech in the early auditory system". The Journal of the Acoustical Society of America. 133 (5): 2818–2833. Bibcode:2013ASAJ..133.2818S. doi:10.1121/1.4795783. PMC 3663870. PMID 23654388.
  22. ^ Paraouty, Nihaad; Stasiak, Arkadiusz; Lorenzi, Christian; Varnet, Léo; Winter, Ian M. (25 April 2018). "Dual Coding of Frequency Modulation in the Ventral Cochlear Nucleus". The Journal of Neuroscience. 38 (17): 4123–4137. doi:10.1523/JNEUROSCI.2107-17.2018. PMC 6596033. PMID 29599389.
  23. ^ Lorenzi, Christian; Debruille, Louis; Garnier, Stéphane; Fleuriot, Pierre; Moore, Brian C. J. (January 2009). "Abnormal processing of temporal fine structure in speech for frequencies where absolute thresholds are normal". The Journal of the Acoustical Society of America. 125 (1): 27–30. Bibcode:2009ASAJ..125...27L. doi:10.1121/1.2939125. PMID 19173391.
  24. ^ Wallaert, Nicolas; Varnet, Léo; Moore, Brian C. J.; Lorenzi, Christian (August 2018). "Sensorineural hearing loss impairs sensitivity but spares temporal integration for detection of frequency modulation" (PDF). The Journal of the Acoustical Society of America. 144 (2): 720–733. Bibcode:2018ASAJ..144..720W. doi:10.1121/1.5049364. PMID 30180712. S2CID 52156063.
  25. ^ Léger, Agnès C.; Lorenzi, Christian; Moore, Brian C. J. (2015-12-15). "Beyond the audiogram: Influence of supra-threshold deficits associated with hearing loss and age on speech intelligibility". Proceedings of the International Symposium on Auditory and Audiological Research. 5: 11–22. ISSN 2596-5522.
  26. ^ Léger, Agnès C.; Moore, Brian C. J.; Gnansia, Dan; Lorenzi, Christian (May 2012). "Effects of spectral smearing on the identification of speech in noise filtered into low- and mid-frequency regions". The Journal of the Acoustical Society of America. 131 (5): 4114–4123. Bibcode:2012ASAJ..131.4114L. doi:10.1121/1.3699265. ISSN 0001-4966. PMID 22559383.
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