1 / 8

The problem

The problem. 1.1 Background What is a voice for the brain? Source/filter theory of voice production: two independent components: larynx (f0) / vocal tract (F) How/where in the brain are these two independent cues processed?

mdupont
Download Presentation

The problem

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The problem • 1.1 Background • What is a voice for the brain? • Source/filter theory of voice production: two independent components: larynx (f0) / vocal tract (F) • How/where in the brain are these two independent cues processed? • Recent advances in voice analysis/synthesis allow an independent manipulation of these two parameters • 1.2 Hypothesis • Manipulating the repetition of f0 vs. F in a series of voices should induce adaptation effects in different parts of auditory cortex. Pitch centre vs. temporal voice areas (TVA)? • Natural vs. unnatural f0/F pairings should lead to different activations in AC, in particular in the TVA • 1.3 Why is it important • Never been investigated; no idea based on what acoustic parameters is voice processed in the brain. Some data on f0, nothing on voice timbre. Better understand the network involved in voice processing • 1.4. Envisaged publication? • Not Science/Nature material, but PLOS/ cerebral cortex?

  2. Experimental Design • Stimulation paradigm: • Pairs of voices uttering “had”: first voice unmodified (adaptor), second with modifications • 3 x 3 (x2) factorial design: • f0= -25%, 0, + 25% (to be piloted) • F= -15%, 0, +15% • Male/female voices • 18 types of pairs. X 20 different voices. 360 stimuli. SOA=4.1 sec. 25% null events as baseline. 33 min . • Task: forced-choice gender decision • Software: MCF (Media Control Function, Digivox, Montreal) • Hardware: Electrostatic headphones (NNL), response buttons • Volunteers: 20 normal volunteers with normal audition (self report ) • Post scanning behavioral data: naturalness & genderness ratings of each stimulus. • MRI parameters: • Rapid event-related design, ‘history controlled’ + ‘efficiency optimized’ order • Independent Voice localizer (10-min optimized bloc design) • Sequences : EPI. Moco (PACE?) • Spatial coverage: small number of slices to cover auditory cortex while allowing a 1-sec silent gap between volumes (to be optimized) • Timing: TR 2s, 270 volumes per run, 4 runs, overall duration: 42 min EPI + 8 min anatomical. About 1 hr15 per participant.

  3. Analysis • Analysis package: BVX • Voxelwise approach (auditory cortex) + Functional localizer: Temporal Voice Area as a functional ROI • Fixed (within subject)+ Random effects design • Pre-processing details: standard pipeline • Analysis strategy: General Linear Model • Level of confidence: new to BV

  4. Expected Results • Expected results, e.g.: • f0 and F : 240 vs. 120 stimuli per subject • Different regions of auditory cortex involved; overlap in TVA? • Natural vs. unnatural pairings: either 80 vs. 80 images per subject, AND/OR regression with naturalness scores • Regression with gender • Strategy, e.g.: • a) optimal result : adaptation to f0 vs F in single pairs • b) fallback options or additional cool result (higher risk): effect of naturalness

  5. Summary of requested CCNi resources • 5.1 Stimulation • Auditory stimulation (NNL) • 5.2 Response • Response pad • 5.3 Number of scanning hours • 20 x 1.30 = 30h • 5.4 Analysis tools • BVX • 5.5 GRID use? • No (until BV is available on the grid) • 5.6 Storage space • Raw : 20 Gb • Analyse ??

  6. Source Larynx, vocal folds => glottal pulses Filter Vocal tract => formants Voice production Fitch. (2000) Trends Cogn Sci

  7. 1,1 F 0,9 f0 0,8 1,2

  8. NATURALNESS GENDER MALE VOICES f0 F F f0 FEMALE VOICES F f0 F f0

More Related