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Tag: Frontiers in Human Neuroscience

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Degraded Acoustics EEG / MEG fMRI Linguistics Papers Publications

New paper out: Simul­ta­ne­ous fMRI–EEG in audi­to­ry cat­e­go­riza­tion by Scharinger et al.

Con­grat­u­la­tions to Obleser lab alum­nus Math­ias Scharinger who this week pub­lished our joint work on simul­ta­ne­ous fMRI–EEG in Fron­tiers in Human Neuroscience!

Simul­ta­ne­ous EEG-fMRI brain sig­na­tures of audi­to­ry cue utilization

by Scharinger, Her­rmann, Nier­haus, & Obleser

See abstract
Opti­mal uti­liza­tion of acoustic cues dur­ing audi­to­ry cat­e­go­riza­tion is a vital skill, par­tic­u­lar­ly when infor­ma­tive cues become occlud­ed or degrad­ed. Con­se­quent­ly, the acoustic envi­ron­ment requires flex­i­ble choos­ing and switch­ing amongst avail­able cues. The present study tar­gets the brain func­tions under­ly­ing such changes in cue uti­liza­tion. Par­tic­i­pants per­formed a cat­e­go­riza­tion task with imme­di­ate feed­back on acoustic stim­uli from two cat­e­gories that var­ied in dura­tion and spec­tral prop­er­ties, while we simul­ta­ne­ous­ly record­ed Blood Oxy­gena­tion Lev­el Depen­dent (BOLD) respons­es in fMRI and elec­troen­cephalo­grams (EEGs). In the first half of the exper­i­ment, cat­e­gories could be best dis­crim­i­nat­ed by spec­tral prop­er­ties. Halfway through the exper­i­ment, spec­tral degra­da­tion ren­dered the stim­u­lus dura­tion the more infor­ma­tive cue. Behav­ioral­ly, degra­da­tion decreased the like­li­hood of uti­liz­ing spec­tral cues. Spec­tral­ly degrad­ing the acoustic sig­nal led to increased alpha pow­er com­pared to non­de­grad­ed stim­uli. The EEG-informed fMRI analy­ses revealed that alpha pow­er cor­re­lat­ed with BOLD changes in infe­ri­or pari­etal cor­tex and right pos­te­ri­or supe­ri­or tem­po­ral gyrus (includ­ing planum tem­po­rale). In both areas, spec­tral degra­da­tion led to a weak­er cou­pling of BOLD response to behav­ioral uti­liza­tion of the spec­tral cue. These data pro­vide con­verg­ing evi­dence from behav­ioral mod­el­ing, elec­tro­phys­i­ol­o­gy, and hemo­dy­nam­ics that (a) increased alpha pow­er medi­ates the inhi­bi­tion of unin­for­ma­tive (here spec­tral) stim­u­lus fea­tures, and that (b) the pari­etal atten­tion net­work sup­ports opti­mal cue uti­liza­tion in audi­to­ry cat­e­go­riza­tion. The results high­light the com­plex cor­ti­cal pro­cess­ing of audi­to­ry cat­e­go­riza­tion under real­is­tic lis­ten­ing chal­lenges.

Ref­er­ences

  • Scharinger M1, Her­rmann B1, Nier­haus T2, Obleser J1. Simul­ta­ne­ous EEG-fMRI brain sig­na­tures of audi­to­ry cue uti­liza­tion. Front Neu­rosci. 2014 Jun 4;8:137. PMID: 24926232. [Open with Read]
Categories
Ageing Auditory Perception Degraded Acoustics EEG / MEG Hearing Loss Neural Oscillations Papers Perception Publications Speech

Strauß strikes again — fron­tiers in Human Neuroscience

It’s only a week ago that we updat­ed you about Antje’s lat­est pub­li­ca­tion at Neu­roIm­age. Today, there is a anoth­er one com­ing in; Antje’s, Mal­te’s & Jonas’ per­spec­tive arti­cle on cor­ti­cal alpha oscil­la­tions is in press at fron­tiers in HUMAN NEUROSCIENCE.

Cor­ti­cal alpha oscil­la­tions as a tool for audi­to­ry selec­tive inhibition

— Strauß, Wöst­mann & Obleser

See abstract
Lis­ten­ing to speech is often demand­ing because of sig­nal degra­da­tions and the pres­ence of dis­tract­ing sounds (i.e., “noise”). The ques­tion how the brain achieves the task of extract­ing only rel­e­vant infor­ma­tion from the mix­ture of sounds reach­ing the ear (i.e., “cock­tail par­ty prob­lem”) is still open. In anal­o­gy to recent find­ings in vision, we pro­pose cor­ti­cal alpha (~10 Hz) oscil­la­tions mea­sur­able using M/EEG as a piv­otal mech­a­nism to selec­tive­ly inhib­it the pro­cess­ing of noise to improve audi­to­ry selec­tive atten­tion to task-rel­e­vant sig­nals. We review ini­tial evi­dence of enhanced alpha activ­i­ty in selec­tive lis­ten­ing tasks, sug­gest­ing a sig­nif­i­cant role of alpha-mod­u­lat­ed noise sup­pres­sion in speech. We dis­cuss the impor­tance of dis­so­ci­at­ing between noise inter­fer­ence in the audi­to­ry periph­ery (i.e., ener­getic mask­ing) and noise inter­fer­ence with more cen­tral cog­ni­tive aspects of speech pro­cess­ing (i.e., infor­ma­tion­al mask­ing). Final­ly, we point out the adverse effects of age-relat­ed hear­ing loss and/or cog­ni­tive decline on audi­to­ry selec­tive inhi­bi­tion. With this per­spec­tive arti­cle, we set the stage for future stud­ies on the inhibito­ry role of alpha oscil­la­tions for speech pro­cess­ing in chal­leng­ing lis­ten­ing situations.

Ref­er­ences

  • Strauß A1, Wöst­mann M2, Obleser J1. Cor­ti­cal alpha oscil­la­tions as a tool for audi­to­ry selec­tive inhi­bi­tion. Front Hum Neu­rosci. 2014 May 28;8:350. PMID: 24904385. [Open with Read]
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]