TABLE OF CONTENTS
Avant-propos……….……...……3
Fundings……….……..5
Remerciements……….………..6
Résumé……….………..……….……….8
Abstract………..………..…....9
Table of contents …..……….………10
Abbreviations………14
A. INTRODUCTION: ………...16
I. Sound, Ear, Hearing, Speech processing and Speech-in-noise………..17
I.1 Sound: from tuning fork to speech signal……..……….…………..………..17
I.2 Auditory ascending and descending pathways ………..19
I.2.1: peripheral auditory system………..…..19
I.2.2: central auditory system……….……...22
I.2.3: auditory descending pathways……….24
I.3 Hearing: from sound to meaning………..24
I.3.1: auditory cortex: the building of auditory object……….…...24
I.3.2: when sound become speech: cortical networks subserving language comprehension ………..26
I.4 Speech-in-noise: Cocktail party at a glance………....30
I.4.1 The physical and perceptual “cocktail party” ……….…..30
I.4.2 The behavioral “cocktail party” ………....36
I.4.3 Physiological and pathological situations of altered processing of Speech-in-noise ……….…37
I.4.3.1 SiN perception in children: a developmental “cocktail party” syndrome……….….…..37
I.4.3.2 Impaired speech perception in noise: the clinical “cocktail party” ………...37
II. Electrophysiological investigation and functional neuroimaging of central auditory pathways ……….…....…..39
II.1 Cellular Basis of brain functional imaging……….……….……...39
II.1.1 Brain cells……….………….…....…39
II.1.2 Electrical and metabolic properties of neurons …….………..…….…40
II.1.2.1 Action potentials……….………..…….41
II.1.2.2 Post synaptic potentials……….…..………..…...41
II.1.2.3 Neuronal metabolic activity……….………..………….42
II.2 Functional neuroimaging of auditory and language processing...……..….……...42
II.2.1 Physiological bases of functional neuroimaging techniques...………..42
II.2.2 Choice of techniques ……….……44
II.2.2.1 Temporal vs spatial resolution……….……….…..44
II.2.2.2 fMRI scanner noise……….…….45
II.3 Magnetoencephalography……….………...47
II.3.1 Instrumentation……….………….……...47
II.3.2 Source reconstruction……….……...48
II.3.3 Auditory magnetic evoked and induced activity……….……..50
II.3.3.1 Auditory magnetic evoked activity……….………51
II.3.3.2 Auditory magnetic induced activity………...53
B. OBJECTIVES ………..…………57
C. EXPERIMENTS ……….…….………..…60
I. Cortical tracking of speech in a cocktail-party auditory scene ...……….………60
I.1 Rationale ……….………60
I.2 Material and Methods ...………..60
I.2.1 Subjects………...60
I.2.2 Experimental paradigm ………...60
I.2.3 Data acquisition ……….……. ………...63
I.2.4 Data preprocessing and coherence analysis……….……….…...63
1.2.4.1 Coherence analysis in sensor space……...………..………...64
1.2.4.2 Coherence analysis in source space……….………...65
1.2.4.3 Group-level analysis in source space………..65
I.2.5 Statistical analyses………..………66
I.3 Results ………...………...69
I.3.1 Differences in the number of artifact-free epochs between listening
conditions………..……….…...…69
I.3.2 Effect of SNR on the intelligibility of attended speech stream…………69
I.3.3 Corticovocal coherence in the absence of multitalker background….69 I.3.4 Corticovocal coherence in SiN conditions……… 70 I.3.5 Cortical processing of the auditory scene in SiN conditions……….76
I.3.6 Effect of SNR in speech-in-noise conditions………. …..76
I.3.7 Correlation between intelligibility of the attended stream and the coherence levels………..…...77
I.4 Discussion ……….…………..…… 77 II. Cortical tracking of speech in noise in children ………..……...82
II.1 Rationale ………....82
II.2 Methods………...………...82
II.2.1 Participants ………..82
II.2.2 Experimental paradigm ..………. ……….83
II.2.3 Data acquisition ……….85
II.2.4 Data preprocessing and coherence analysis……….85
II.2.4.1 Coherence analysis in sensor space………86
II.2.4.2 Coherence analysis in source space………87
II.2.4.3 Group-level analyses in source space………..…….….87
II.2.5 Experimental design and statistical analyses……….………. ….88 II.3 Results………...………..91
II.3.1 Comparison of SiN perception in adults vs. children…….……….91
II.3.2 Effect of SNR on the comprehension and the intelligibility of the Attended stream……….92
II.3.3 Cortical tracking of speech in the Noiseless condition………..93
II.3.4 Cortical tracking of speech in SiN conditions………..98
II.3.5 Cortical processing of the auditory scene in SiN conditions…………..99
II.3.6 Effect of age group, SNR, and hemispheric lateralization on cortical tracking of speech……… 101 II.4 Discussion ………..………104
III. Cortical tracking of speech in noise in iSPin………...…108
III.1 Rationale ………...……108
III.2 Methods ……….……108
III.2.1 Participants………...108
III.2.2 Experimental paradigm……….……… 109 III.2.3 Data acquisition ………...109
III.2.4 Data preprocessing, coherence analysis and functional connectivity mapping………110
III.2.4.1 Cortical tracking of speech streams in sensor space….…..111
III.2.4.2 Cortical tracking of speech streams in source space…..….111
III.2.4.3 Seed-based FC mapping in source space………..…….. ….112 III.2.4.4 Group averaging……….………112
III.2.5 Statistical analyses……….………..113
III.3 Results ………..………..…116
III.3.1 Comparison of auditory perception and attention between groups of participants………..………..…116
III.3.2 Effect of listening conditions on intelligibility ratings and comprehension scores………..…………..….116
III.3.3 Significance of individual cortical tracking of speech …………..…….118
III.3.4 Group-level cortical tracking of speech………..…....119
III.3.5 Significance of selective cortical tracking of the attended speech.119 III.3.6 Group comparison of cortical tracking of the attended speech…...119
III.3.7 Effect of group, listening condition, and hemispheric lateralization on cortical tracking of speech……….………..……..119
III.3.8 Comparison of seed-based functional connectivity between groups of participants……….………..…126 III.4 Discussion ………129
D. GENERAL DISCUSSION……….
……...133
E. REFERENCES………...………..…….143 F. ARTICLES………...…………..….166
