Category: Papers

Categories
Neural Oscillations Papers Publications Speech

New paper out: “Don’t be enslaved by the enve­lope” – Com­ment on Giraud & Poep­pel (2012)

Today appears a com­ment / opin­ion arti­cle, with a tad bit of fresh evi­dence from our lab, that is main­ly a reply to Anne-Lise Giraud and David Poeppel’s recent “per­spec­tive” arti­cle on Neur­al oscil­la­tions in speech.

We loved that arti­cle, obvi­ous­ly, but after the ini­tial excite­ment, a few con­cerns stuck with us. In essence, the prob­lems are (i) how to define theta for the pur­pos­es of analysing speech com­pre­hen­sion process­es, (ii) not to over­ly focus on the speech enve­lope (i.e., not to neglect spec­tral / fine-struc­ture aspects of speech), and (iii) the unsolved chicken–egg prob­lem of how neur­al entrain­ment and speech intel­li­gi­bil­i­ty real­ly relate to each other.

But read for your­self (It’s pleas­ant­ly short!).

Ref­er­ences

  • Obleser J, Her­rmann B, Hen­ry MJ. Neur­al Oscil­la­tions in Speech: Don’t be Enslaved by the Enve­lope. Front Hum Neu­rosci. 2012 Aug 31;6:250. PMID: 22969717. [Open with Read]
Categories
EEG / MEG Evoked Activity Linguistics Papers Perception Place of Articulation Features Publications Speech

New paper in press — Scharinger et al., PLOS ONE [Update]

We are hap­py that our paper

A Sparse Neur­al Code for Some Speech Sounds but Not for Others

is sched­uled for pub­li­ca­tion in PLOS ONE on July 16th, 2012.

This is also our first paper in col­lab­o­ra­tion with Alexan­dra Ben­dix­en from the Uni­ver­si­ty of Leipzig.

The research report­ed in this arti­cle pro­vides an exten­sion of the pre­dic­tive cod­ing frame­work onto speech sounds and assumes that audi­to­ry pro­cess­ing uses pre­dic­tions that are not only derived from ongo­ing con­tex­tu­al updates, but also from long-term mem­o­ry rep­re­sen­ta­tions — neur­al codes — of speech sounds. Using the Ger­man min­i­mal pair [lats]/[laks] (bib/salmon) in a pas­sive-odd­ball design, we find the expect­ed Mis­match Neg­a­tiv­i­ty (MMN) asym­me­try that is com­pat­i­ble with a pre­dic­tive cod­ing frame­work, but also with lin­guis­tic under­spec­i­fi­ca­tion theory.

[Update]

Paper is avail­able here.

Ref­er­ences

  • Scharinger M, Ben­dix­en A, Tru­jil­lo-Bar­reto NJ, Obleser J. A sparse neur­al code for some speech sounds but not for oth­ers. PLoS One. 2012;7(7):e40953. PMID: 22815876. [Open with Read]
Categories
Degraded Acoustics fMRI Noise-Vocoded Speech Papers Publications Speech

New paper in press: Erb et al., Neu­ropsy­cholo­gia [Update]

I am very proud to announce our first paper that was entire­ly planned, con­duct­ed, analysed and writ­ten up since our group has been in exis­tence. Julia joined me as the first PhD stu­dent in Decem­ber 2010, and has since been busy doing awe­some work. Check out her first paper!

Audi­to­ry skills and brain mor­phol­o­gy pre­dict indi­vid­ual dif­fer­ences in adap­ta­tion to degrad­ed speech

Noise-vocod­ed speech is a spec­tral­ly high­ly degrad­ed sig­nal, but it pre­serves the tem­po­ral enve­lope of speech. Lis­ten­ers vary con­sid­er­ably in their abil­i­ty to adapt to this degrad­ed speech sig­nal. Here, we hypoth­e­sized that indi­vid­ual dif­fer­ences in adap­ta­tion to vocod­ed speech should be pre­dictable by non-speech audi­to­ry, cog­ni­tive, and neu­roanatom­i­cal fac­tors. We test­ed eigh­teen nor­mal-hear­ing par­tic­i­pants in a short-term vocod­ed speech-learn­ing par­a­digm (lis­ten­ing to 100 4- band-vocod­ed sen­tences). Non-speech audi­to­ry skills were assessed using ampli­tude mod­u­la­tion (AM) rate dis­crim­i­na­tion, where mod­u­la­tion rates were cen­tered on the speech-rel­e­vant rate of 4 Hz. Work­ing mem­o­ry capac­i­ties were eval­u­at­ed, and struc­tur­al MRI scans were exam­ined for anatom­i­cal pre­dic­tors of vocod­ed speech learn­ing using vox­el-based mor­phom­e­try. Lis­ten­ers who learned faster to under­stand degrad­ed speech showed small­er thresh­olds in the AM dis­crim­i­na­tion task. Anatom­i­cal brain scans revealed that faster learn­ers had increased vol­ume in the left thal­a­mus (pul­v­inar). These results sug­gest that adap­ta­tion to vocod­ed speech ben­e­fits from indi­vid­ual AM dis­crim­i­na­tion skills. This abil­i­ty to adjust to degrad­ed speech is fur­ther­more reflect­ed anatom­i­cal­ly in an increased vol­ume in an area of the thal­a­mus, which is strong­ly con­nect­ed to the audi­to­ry and pre­frontal cor­tex. Thus, indi­vid­ual audi­to­ry skills that are not speech-spe­cif­ic and left thal­a­mus gray mat­ter vol­ume can pre­dict how quick­ly a lis­ten­er adapts to degrad­ed speech. Please be in touch with Julia Erb if you are inter­est­ed in a preprint as soon as we get hold of the final, type­set manuscript.

[Update#1]: Julia has also pub­lished a blog post on her work.

[Update#2] Paper is avail­able here.

Ref­er­ences

  • Erb J, Hen­ry MJ, Eis­ner F, Obleser J. Audi­to­ry skills and brain mor­phol­o­gy pre­dict indi­vid­ual dif­fer­ences in adap­ta­tion to degrad­ed speech. Neu­ropsy­cholo­gia. 2012 Jul;50(9):2154–64. PMID: 22609577. [Open with Read]
Categories
Auditory Cortex Auditory Speech Processing fMRI Papers Publications Speech

New paper out: McGet­ti­gan et al., Neuropsychologia


Last years’s lab guest and long-time col­lab­o­ra­tor Car­olyn McGet­ti­gan has put out anoth­er one:

Speech com­pre­hen­sion aid­ed by mul­ti­ple modal­i­ties: Behav­iour­al and neur­al interactions

I had the plea­sure to be involved ini­tial­ly, when Car­olyn con­ceived a lot of this, and when things came togeth­er in the end. Car­olyn nice­ly demon­strates how vary­ing audio and visu­al clar­i­ty comes togeth­er with the seman­tic ben­e­fits a lis­ten­er can get from the famous Kalikow SPIN (speech in noise) sen­tences. The data high­light pos­te­ri­or STS and the fusiform gyrus as sites for con­ver­gence of audi­to­ry, visu­al and lin­guis­tic information.

Check it out!

Ref­er­ences

  • McGet­ti­gan C, Faulkn­er A, Altarel­li I, Obleser J, Baver­stock H, Scott SK. Speech com­pre­hen­sion aid­ed by mul­ti­ple modal­i­ties: behav­iour­al and neur­al inter­ac­tions. Neu­ropsy­cholo­gia. 2012 Apr;50(5):762–76. PMID: 22266262. [Open with Read]
Categories
Auditory Perception Auditory Speech Processing EEG / MEG Evoked Activity Linguistics Papers Place of Articulation Features Publications Speech

New paper out in Jour­nal of Speech, Lan­guage, & Hear­ing Research [Update]

We are hap­py to announce that our paper “Asym­me­tries in the pro­cess­ing of vow­el height” will be appear­ing in the Jour­nal of Speech, Lan­guage, & Hear­ing Research, authored by Philip Mon­a­han, William Idsar­di and Math­ias Scharinger. A short sum­ma­ry is giv­en below:

Pur­pose: Speech per­cep­tion can be described as the trans­for­ma­tion of con­tin­u­ous acoustic infor­ma­tion into dis­crete mem­o­ry rep­re­sen­ta­tions. There­fore, research on neur­al rep­re­sen­ta­tions of speech sounds is par­tic­u­lar­ly impor­tant for a bet­ter under­stand­ing of this trans­for­ma­tion. Speech per­cep­tion mod­els make spe­cif­ic assump­tions regard­ing the rep­re­sen­ta­tion of mid vow­els (e.g., [{varepsilon}]) that are artic­u­lat­ed with a neu­tral posi­tion in regard to height. One hypoth­e­sis is that their rep­re­sen­ta­tion is less spe­cif­ic than the rep­re­sen­ta­tion of vow­els with a more spe­cif­ic posi­tion (e.g., [æ]).

Method: In a mag­ne­toen­cephalog­ra­phy study, we test­ed the under­spec­i­fi­ca­tion of mid vow­el in Amer­i­can Eng­lish. Using a mis­match neg­a­tiv­i­ty (MMN) par­a­digm, mid and low lax vow­els ([{varepsilon}]/[æ]), and high and low lax vow­els ([I]/[æ]), were opposed, and M100/N1 dipole source para­me­ters as well as MMN laten­cy and ampli­tude were examined.

Results: Larg­er MMNs occurred when the mid vow­el [{varepsilon}] was a deviant to the stan­dard [æ], a result con­sis­tent with less spe­cif­ic rep­re­sen­ta­tions for mid vow­els. MMNs of equal mag­ni­tude were elicit­ed in the high–low com­par­i­son, con­sis­tent with more spe­cif­ic rep­re­sen­ta­tions for both high and low vow­els. M100 dipole loca­tions sup­port ear­ly vow­el cat­e­go­riza­tion on the basis of lin­guis­ti­cal­ly rel­e­vant acoustic–phonetic features.

Con­clu­sion: We take our results to reflect an abstract long-term rep­re­sen­ta­tion of vow­els that do not include redun­dant spec­i­fi­ca­tions at very ear­ly stages of pro­cess­ing the speech sig­nal. More­over, the dipole loca­tions indi­cate extrac­tion of dis­tinc­tive fea­tures and their map­ping onto rep­re­sen­ta­tion­al­ly faith­ful cor­ti­cal loca­tions (i.e., a fea­ture map).

[Update]

The paper is avail­able here.

Ref­er­ences

  • Scharinger M, Mon­a­han PJ, Idsar­di WJ. Asym­me­tries in the pro­cess­ing of vow­el height. J Speech Lang Hear Res. 2012 Jun;55(3):903–18. PMID: 22232394. [Open with Read]
Categories
Auditory Speech Processing Degraded Acoustics EEG / MEG Neural Oscillations Noise-Vocoded Speech Papers Publications Speech

New paper accept­ed in Cere­bral Cor­tex [Update]

Obleser, J., Weisz, N. (in press) Sup­pressed alpha oscil­la­tions pre­dict intel­li­gi­bil­i­ty of speech and its acoustic details. Cere­bral Cortex.

[Update]

Paper is avail­able here.

Ref­er­ences

  • Obleser J, Weisz N. Sup­pressed alpha oscil­la­tions pre­dict intel­li­gi­bil­i­ty of speech and its acoustic details. Cereb Cor­tex. 2012 Nov;22(11):2466–77. PMID: 22100354. [Open with Read]
Categories
Auditory Cortex EEG / MEG Evoked Activity Linguistics Papers Publications

New Paper out: HELLO? in press (Neu­roIm­age)

Pho­net­ic cues instan­ta­neous­ly mapped onto dialec­tal cat­e­gories appear to be extract­ed at ear­ly moments in audi­to­ry speech per­cep­tion, as we try to show in our paper

You had me at “Hel­lo”: Rapid extrac­tion of dialect infor­ma­tion from spo­ken words

to appear in Neu­roIm­age (Math­ias Scharinger, Philip Mon­a­han, William Idsardi).

In a mod­i­fied pas­sive odd­ball design, we com­pare the Mis­match Neg­a­tiv­i­ty (MMN) to deviants in one Amer­i­can Eng­lish dialect (Stan­dard Amer­i­can Eng­lish or African-Amer­i­can Ver­nac­u­lar Eng­lish) to the stan­dards of the respec­tive oth­er dialect. In a con­trol con­di­tion, deviants with­in the same dialects have the same aver­aged acoustic dis­tance to their stan­dards than the cross-dialec­tal aver­aged acoustic dis­tance. Stan­dards and deviants were always spo­ken exem­plars of ‘Hel­lo’ in both dialects (ca. 500 ms). MMN effects are sig­nif­i­cant in the cross-dialec­tal con­di­tion only, imply­ing that a pure acoustic stan­dard-deviant dis­tance is not suf­fi­cient to elic­it sub­stan­tial mis­match effects. We inter­pret these find­ings, togeth­er with N1m source local­iza­tion data, as evi­dence for a rapid extrac­tion of dialect infor­ma­tion via salient acoustic-pho­net­ic cues. From the loca­tion and ori­en­ta­tion of the N1m source activ­i­ty, we can infer that dialect switch­es from stan­dards to deviants engage areas in supe­ri­or tem­po­ral sulcus/gyrus.

Ref­er­ences

  • Scharinger M, Mon­a­han PJ, Idsar­di WJ. You had me at “Hel­lo”: Rapid extrac­tion of dialect infor­ma­tion from spo­ken words. Neu­roim­age. 2011 Jun 15;56(4):2329–38. PMID: 21511041. [Open with Read]
Categories
Auditory Cortex EEG / MEG Evoked Activity Papers Place of Articulation Features Publications

New Paper out: Com­pre­hen­sive map of a language’s vow­el space

We are glad to announce that our paper (Math­ias Scharinger, Saman­tha Poe, & William Idsar­di) on cor­ti­cal rep­re­sen­ta­tions of Turk­ish vow­els is in press in Jour­nal of Cog­ni­tive Neu­ro­science. In this paper, we extend pre­vi­ous meth­ods of obtain­ing cen­ters of cor­ti­cal activ­i­ty evoked by vow­el exem­plars (e.g. Obleser et al., 2003, on Ger­man) and pro­vide an N1m ECD (Equiv­a­lent Cur­rent Dipole) map of the entire vow­el space of Turk­ish. Intrigu­ing­ly, ECD loca­tions mapped near­ly per­fect to loca­tions in F2/F1 space, although our mod­el com­par­i­son sug­gest­ed that inclu­sion of dis­crete fea­ture based pre­dic­tors for both loca­tions as well as col­lo­ca­tions of vow­els in audi­to­ry cor­tex improves the mod­el fits sub­stan­tial­ly. We dis­cuss the find­ings on the back­ground of neur­al cod­ing schemes for speech-relat­ed audi­to­ry categories.

Fig­ure 1: Loca­tions of Turk­ish vow­el stim­uli in acoustic space (F1,F2, top pan­el) and N1m ECD loca­tions in cor­ti­cal space (lat­er­al-medi­al/an­te­ri­or-pos­te­ri­or/in­fe­ri­or-supe­ri­or, bot­tom panel).

UPDATE: Paper is avail­able here.

Ref­er­ences

  • Scharinger M, Idsar­di WJ, Poe S. A com­pre­hen­sive three-dimen­sion­al cor­ti­cal map of vow­el space. J Cogn Neu­rosci. 2011 Dec;23(12):3972–82. PMID: 21568638. [Open with Read]