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Tag: Scharinger

Categories
EEG / MEG Neural Oscillations Neural Phase Papers Publications

Strauß again — in Jour­nal of Neuroscience

Alum­na Dr. Antje Strauß just got anoth­er paper on:

Alpha Phase Deter­mines Suc­cess­ful Lex­i­cal Deci­sion in Noise

by Antje Strauß, Mol­ly Hen­ry, Math­ias Scharinger, and Jonas Obleser

appeared in Jour­nal of Neu­ro­science. Check the abstract below;

Abstract
Psy­chophys­i­cal tar­get detec­tion has been shown to be mod­u­lat­ed by slow oscil­la­to­ry brain phase. How­ev­er, thus far, only low-lev­el sen­so­ry stim­uli have been used as tar­gets. The cur­rent human elec­troen­cephalog­ra­phy (EEG) study exam­ined the influ­ence of neur­al oscil­la­to­ry phase on a lex­i­cal-deci­sion task per­formed for stim­uli embed­ded in noise. Neur­al phase angles were com­pared for cor­rect ver­sus incor­rect lex­i­cal deci­sions using a phase bifur­ca­tion index (BI), which quan­ti­fies dif­fer­ences in mean phase angles and phase con­cen­tra­tions between cor­rect and incor­rect tri­als. Neur­al phase angles in the alpha fre­quen­cy range (8–12 Hz) over right ante­ri­or sen­sors were approx­i­mate­ly antiphase in a pres­tim­u­lus time win­dow, and thus suc­cess­ful­ly dis­tin­guished between cor­rect and incor­rect lex­i­cal deci­sions. More­over, alpha-band oscil­la­tions were again approx­i­mate­ly antiphase across par­tic­i­pants for cor­rect ver­sus incor­rect tri­als dur­ing a lat­er peri­s­tim­u­lus time win­dow (∼500 ms) at left-cen­tral elec­trodes. Strik­ing­ly, lex­i­cal deci­sion accu­ra­cy was not pre­dict­ed by either event-relat­ed poten­tials (ERPs) or oscil­la­to­ry pow­er mea­sures. We sug­gest that cor­rect lex­i­cal deci­sions depend both on suc­cess­ful sen­so­ry pro­cess­ing, which is made pos­si­ble by the align­ment of stim­u­lus onset with an opti­mal alpha phase, as well as inte­gra­tion and weight­ing of deci­sion­al infor­ma­tion, which is cou­pled to alpha phase imme­di­ate­ly fol­low­ing the crit­i­cal manip­u­la­tion that dif­fer­en­ti­at­ed words from pseu­do­words. The cur­rent study con­sti­tutes a first step toward char­ac­ter­iz­ing the role of dynam­ic oscil­la­to­ry brain states for high­er cog­ni­tive func­tions, such as spo­ken word recognition.
Categories
Degraded Acoustics EEG / MEG Linguistics Neural Oscillations Neural Phase Papers Perception Publications Speech

New paper in press in the Jour­nal of Neu­ro­science: Strauß, Hen­ry, Scharinger, & Obleser

Con­grat­u­la­tions to just-grad­u­at­ed for­mer AC PhD stu­dent and fresh GIPSA/Grenoble Post­doc Antje Strauß, who today had the last data set from her PhD the­sis accept­ed as a paper in The Jour­nal of Neu­ro­science. We are all very happy!

The paper is enti­tled “Alpha phase deter­mines suc­cess­ful lex­i­cal deci­sion in noise” and con­tains arguably the first data set to extend prin­ci­ples of (alpha, 8–12 Hz) pre-stim­u­lus phase depen­dence from low-lev­el psy­chophysics to more com­plex lan­guage or cog­ni­tive process­es, here: lex­i­cal decision.

A big hel­lo to AC friend and col­league Niko Busch, by the way, whose bifur­ca­tion index mea­sure served our pur­pos­es very well here!

We will update accord­ing­ly, but mean­while, here is the abstract and my favourite fig­ure from the paper.

Abstract
Psy­chophys­i­cal tar­get detec­tion has been shown to be mod­u­lat­ed by slow oscil­la­to­ry brain phase. How­ev­er, thus far, only low-lev­el sen­so­ry stim­uli have been used as tar­gets. The cur­rent human elec­troen­cephalog­ra­phy study exam­ined the influ­ence of neur­al oscil­la­to­ry phase on a lex­i­cal-deci­sion task per­formed for stim­uli embed­ded in noise. Neur­al phase angles were com­pared for cor­rect ver­sus incor­rect lex­i­cal deci­sions using a phase bifur­ca­tion index, which quan­ti­fies dif­fer­ences in mean phase angles and phase con­cen­tra­tions between cor­rect and incor­rect tri­als. Neur­al phase angles in the alpha fre­quen­cy range (8–12 Hz) over right ante­ri­or sen­sors were approx­i­mate­ly anti-phase in a pre-stim­u­lus time win­dow, and thus suc­cess­ful­ly dis­tin­guished between cor­rect and incor­rect lex­i­cal deci­sions. More­over, alpha-band oscil­la­tions were again approx­i­mate­ly anti-phase across par­tic­i­pants for cor­rect ver­sus incor­rect tri­als dur­ing a lat­er peri-stim­u­lus time-win­dow (around 500 ms) at left-cen­tral elec­trodes. Strik­ing­ly, lex­i­cal deci­sion accu­ra­cy was not pre­dict­ed by either ERPs or oscil­la­to­ry pow­er mea­sures. We sug­gest that cor­rect lex­i­cal deci­sions depend both on suc­cess­ful sen­so­ry pro­cess­ing, which is made pos­si­ble by the align­ment of stim­u­lus onset with an opti­mal alpha phase, as well as inte­gra­tion and weight­ing of deci­sion­al infor­ma­tion, which is cou­pled to alpha phase imme­di­ate­ly fol­low­ing the crit­i­cal manip­u­la­tion that dif­fer­en­ti­at­ed words from pseu­do­words. The cur­rent study con­sti­tutes a first step towards char­ac­ter­iz­ing the role of dynam­ic oscil­la­to­ry brain states for high­er cog­ni­tive func­tions such as spo­ken word recognition.

Untitled copy

Categories
fMRI Linguistics Papers Publications Speech

New paper in Neu­roIm­age by Scharinger, Hen­ry, & Obleser [UPDATED]

A new paper is about to appear in Neu­roim­age on

Acoustic cue selec­tion and dis­crim­i­na­tion under degra­da­tion: Dif­fer­en­tial con­tri­bu­tions of the infe­ri­or pari­etal and pos­te­ri­or tem­po­ral cortices

by Math­ias Scharinger, Mol­ly J. Hen­ry, Jonas Obleser

Abstract
Cat­e­go­riz­ing sounds is vital for adap­tive human behav­ior. Accord­ing­ly, chang­ing lis­ten­ing sit­u­a­tions (exter­nal noise or periph­er­al hear­ing loss in aging) that may be accom­pa­nied by changes in dis­crim­inabil­i­ty, require lis­ten­ers to flex­i­bly adjust their cat­e­go­riza­tion strate­gies, some­times by changes in uti­liz­ing avail­able acoustic cues.
In this func­tion­al Mag­net­ic Res­o­nance Imag­ing (fMRI) study, we inves­ti­gate the cat­e­go­riza­tion of nov­el, non-speech audi­to­ry stim­uli that var­ied in over­all dis­crim­inabil­i­ty. More­over, we manip­u­late the rel­a­tive infor­ma­tive­ness of a dura­tion ver­sus a spec­tral-peak cue by adding spec­tral degra­da­tion in the mid­dle of the exper­i­ment. The results demon­strate dif­fer­ent roles of tem­po­ral and pari­etal brain areas for audi­to­ry cat­e­go­riza­tion: Tem­po­ral cor­tex acti­va­tion, in par­tic­u­lar in pos­te­ri­or parts of the right supe­ri­or tem­po­ral gyrus, scaled with dis­crim­inabil­i­ty, while left pari­etal cor­tex acti­va­tion was asso­ci­at­ed with changes in cue uti­liza­tion after the appli­ca­tion of spec­tral degradation.
This work extends pre­vi­ous research on audi­to­ry cat­e­go­riza­tion. Impor­tant­ly, the involve­ment of the left infe­ri­or pari­etal lob­ule in changes of cue uti­liza­tion sup­ports its role in domain-gen­er­al process­es that sup­port cat­e­go­riza­tion. Fur­ther, the sen­si­tiv­i­ty of the right pos­te­ri­or supe­ri­or tem­po­ral gyrus to stim­u­lus dis­crim­inabil­i­ty adds to pre­vi­ous find­ings regard­ing its role in audi­to­ry processing. 
[UPDATE] Link added.

Ref­er­ences

  • Scharinger M1, Hen­ry MJ2, Obleser J2. Acoustic cue selec­tion and dis­crim­i­na­tion under degra­da­tion: Dif­fer­en­tial con­tri­bu­tions of the infe­ri­or pari­etal and pos­te­ri­or tem­po­ral cor­tices. Neu­roim­age. 2015 Feb 1;106:373–81. PMID: 25481793. [Open with Read]
Categories
Auditory Neuroscience Auditory Perception Auditory Speech Processing Clinical relevance Degraded Acoustics Gyrus Angularis Linguistics Noise-Vocoded Speech Papers Perception Psychology Speech

New paper in press: Hartwigsen, Golombek, & Obleser in Cor­tex [UPDATED]

In a col­lab­o­ra­tion with the Uni­ver­si­ty Clin­ic of Leipzig and Prof Dr Gesa Hartwigsen (now Uni­ver­si­ty of Kiel), a new paper is to appear in “Cor­tex”, in the forth­com­ing spe­cial issue on Pre­dic­tion in Speech and Lan­guage, edit­ed by Alessan­dro Tavano and AC alum­nus Math­ias Scharinger.

Repet­i­tive tran­scra­nial mag­net­ic stim­u­la­tion over left angu­lar gyrus mod­u­lates the pre­dictabil­i­ty gain in degrad­ed speech comprehension

Hartwigsen G, Golombek T, & Obleser J.

See abstract
Increased neur­al activ­i­ty in left angu­lar gyrus (AG) accom­pa­nies suc­cess­ful com­pre­hen­sion of acousti­cal­ly degrad­ed but high­ly pre­dictable sen­tences, as pre­vi­ous func­tion­al imag­ing stud­ies have shown. How­ev­er, it remains unclear whether the left AG is causal­ly rel­e­vant for the com­pre­hen­sion of degrad­ed speech. Here, we applied tran­sient vir­tu­al lesions to either the left AG or supe­ri­or pari­etal lobe (SPL, as a con­trol area) with repet­i­tive tran­scra­nial mag­net­ic stim­u­la­tion (rTMS) while healthy vol­un­teers lis­tened to and repeat­ed sen­tences with high- vs. low-pre­dictable end­ings and dif­fer­ent noise vocod­ing lev­els. We expect­ed that rTMS of AG should selec­tive­ly mod­u­late the pre­dictabil­i­ty gain (i.e., the com­pre­hen­sion ben­e­fit from sen­tences with high-pre­dictable end­ings) at a medi­um degra­da­tion lev­el. We found that rTMS of AG indeed reduced the pre­dictabil­i­ty gain at a medi­um degra­da­tion lev­el of 4‑band noise vocod­ing (rel­a­tive to con­trol rTMS of SPL). In con­trast, the behav­ioral per­tur­ba­tion induced by rTMS reversed with increased sig­nal qual­i­ty. Hence, at 8‑band noise vocod­ing, rTMS over AG vs. SPL increased the over­all pre­dictabil­i­ty gain. Togeth­er, these results show that the degree of the rTMS inter­fer­ence depend­ed joint­ly on sig­nal qual­i­ty and pre­dictabil­i­ty. Our results pro­vide the first causal evi­dence that the left AG is a crit­i­cal node for facil­i­tat­ing speech com­pre­hen­sion in chal­leng­ing lis­ten­ing conditions.

Screen Shot 2014-09-11 at 21.19.17

Check it out soon!

Ref­er­ences

  • Hartwigsen G1, Golombek T2, Obleser J3. Repet­i­tive tran­scra­nial mag­net­ic stim­u­la­tion over left angu­lar gyrus mod­u­lates the pre­dictabil­i­ty gain in degrad­ed speech com­pre­hen­sion. Cor­tex. 2014 Sep 18. PMID: 25444577. [Open with Read]
Categories
fMRI Papers Perception Publications

New paper in press: Her­rmann et al in NeuroImage

Dr Björn Her­rmann did it again, and is in press at Neu­roIm­age with Her­rmann, Hen­ry, Scharinger, & Obleser on

Sup­ple­men­tary motor area acti­va­tions pre­dict indi­vid­ual dif­fer­ences in tem­po­ral-change sen­si­tiv­i­ty and its illu­so­ry distortions

See abstract
Per­cep­tion of time and tem­po­ral change are crit­i­cal for human cog­ni­tion. Yet, per­cep­tion of tem­po­ral change is sus­cep­ti­ble to con­tex­tu­al influ­ences such as changes of a sound’s pitch. Using func­tion­al mag­net­ic res­o­nance imag­ing (fMRI), the cur­rent study aimed to inves­ti­gate per­cep­tion of tem­po­ral rate change and pitch-induced illu­so­ry dis­tor­tions. In a 6 × 6 design, human par­tic­i­pants (N=19) lis­tened to fre­quen­cy-mod­u­lat­ed sounds (~4 Hz) that var­ied over time in both mod­u­la­tion rate and pitch. Par­tic­i­pants judged the direc­tion of rate change (‘speed­ing up’ vs. ‘slow­ing down’), while ignor­ing changes in pitch. Behav­ioral­ly, rate judg­ments were strong­ly biased by pitch changes: Par­tic­i­pants per­ceived rate to slow down when pitch decreased and to speed up when pitch increased (‘rate-change illu­sion’). The fMRI data revealed acti­va­tion increas­es with increas­ing task dif­fi­cul­ty in pre-SMA, left puta­men, and right IFG/insula. Impor­tant­ly, acti­va­tion in pre-SMA was linked to the per­cep­tu­al sen­si­tiv­i­ty to dis­crim­i­nate rate changes and, togeth­er with the left puta­men, to rel­a­tive reduc­tions in sus­cep­ti­bil­i­ty to pitch-induced illu­so­ry dis­tor­tions. Right IFG/insula acti­va­tions, how­ev­er, only scaled with task dif­fi­cul­ty. These data offer a dis­tinc­tion between regions whose acti­va­tions scale with per­cep­tu­al sen­si­tiv­i­ty to fea­tures of time (pre-SMA) and those that more gen­er­al­ly sup­port behav­ing in dif­fi­cult lis­ten­ing con­di­tions (IFG/insula). Hence, the data under­score that indi­vid­ual dif­fer­ences in time per­cep­tion can be relat­ed to dif­fer­ent pat­terns of neu­ro­func­tion­al activation.

Ref­er­ences

  • Her­rmann B1, Hen­ry MJ2, Scharinger M2, Obleser J2. Sup­ple­men­tary motor area acti­va­tions pre­dict indi­vid­ual dif­fer­ences in tem­po­ral-change sen­si­tiv­i­ty and its illu­so­ry dis­tor­tions. Neu­roim­age. 2014 Jul 23;101C:370–379. PMID: 25064666. [Open with Read]
Categories
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
EEG / MEG Linguistics Neural Oscillations Papers Publications

New paper out: Dis­so­ci­a­tion of alpha and theta oscil­la­tions Strauß, Kotz, Scharinger, Obleser

We are very hap­py to announce that PhD stu­dent Antje Strauß got her paper

Alpha and theta brain oscil­la­tions index dis­so­cia­ble process­es in spo­ken word recognition

accept­ed at Neu­roIm­age. Con­grat­u­la­tions! Find her paper here.

See the Abstract
Slow neur­al oscil­la­tions (∼ 1–15 Hz) are thought to orches­trate the neur­al process­es of spo­ken lan­guage com­pre­hen­sion. How­ev­er, func­tion­al sub­di­vi­sions with­in this broad range of fre­quen­cies are dis­put­ed, with most stud­ies hypoth­e­siz­ing only about sin­gle fre­quen­cy bands. The present study uti­lizes an estab­lished par­a­digm of spo­ken word recog­ni­tion (lex­i­cal deci­sion) to test the hypoth­e­sis that with­in the slow neur­al oscil­la­to­ry fre­quen­cy range, dis­tinct func­tion­al sig­na­tures and cor­ti­cal net­works can be iden­ti­fied at least for theta- (∼ 3–7 Hz) and alpha-fre­quen­cies (∼ 8–12 Hz). Lis­ten­ers per­formed an audi­to­ry lex­i­cal deci­sion task on a set of items that formed a word–pseudoword con­tin­u­um: rang­ing from (1) real words over (2) ambigu­ous pseu­do­words (devi­at­ing from real words only in one vow­el; com­pa­ra­ble to nat­ur­al mis­pro­nun­ci­a­tions in speech) to (3) pseu­do­words (clear­ly devi­at­ing from real words by ran­dom­ized syl­la­bles). By means of time–frequency analy­sis and spa­tial fil­ter­ing, we observed a dis­so­ci­a­tion into dis­tinct but simul­ta­ne­ous pat­terns of alpha pow­er sup­pres­sion and theta pow­er enhance­ment. Alpha exhib­it­ed a para­met­ric sup­pres­sion as items increas­ing­ly matched real words,in line with low­ered func­tion­al inhi­bi­tion in a left-dom­i­nant lex­i­cal pro­cess­ing net­work for more word-like input. Simul­ta­ne­ous­ly, theta pow­er in a bilat­er­al fron­to-tem­po­ral net­work was selec­tive­ly enhanced for ambigu­ous pseu­do­words only. Thus, enhanced alpha pow­er can neu­ral­ly “gate” lex­i­cal inte­gra­tion, while enhanced theta pow­er might index func­tion­al­ly more spe­cif­ic ambi­gu­i­ty-res­o­lu­tion process­es. To this end, a joint analy­sis of both fre­quen­cy bands pro­vides neur­al evi­dence for par­al­lel process­es in achiev­ing spo­ken word recognition.

Ref­er­ences

  • Strauβ A1, Kotz SA2, Scharinger M3, Obleser J3. Alpha and theta brain oscil­la­tions index dis­so­cia­ble process­es in spo­ken word recog­ni­tion. Neu­roim­age. 2014 Apr 18. PMID: 24747736. [Open with Read]
Categories
Editorial Notes Events Media Publications

SNAP sum­ma­ry and impressions

The SNAP work­shop (Sig­nal and Noise along the Audi­to­ry Path­way) is behind us.

It is safe to say that it has been a great suc­cess. We will care­ful­ly look into the eval­u­a­tion forms you pro­vid­ed, and we will inform here in due course whether and when a 2nd SNAP (poten­tial­ly 2015) is in the making.

Let us thank all of you who made SNAP hap­pen. It turned a fun and suc­cess­ful sci­en­tif­ic year 2013 into an even greater one. Thank you! We hope to see you soon again, somewhere.

Now, here are some impres­sions of SNAP 2013:

P.S. Here you find Jonas’ clos­ing sum­ma­ry notes:

SNAP 2013 ad hoc sum­ma­ry — Jonas Obleser