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Category: Auditory Cortex

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Auditory Cortex EEG / MEG Papers Perception Publications

New paper in press in the Euro­pean Jour­nal of Neu­ro­science: Wöst­mann et al demon­strate that the pow­er of pres­tim­u­lus alpha oscil­la­tions direct­ly relates to con­fi­dence in pitch-discrimination

What is the mech­a­nis­tic rel­e­vance of neur­al alpha oscil­la­tions (~10 Hz) for per­cep­tion? To answer this ques­tion, we analysed EEG data from a task that required par­tic­i­pants to com­pare the pitch of two tones that were, unbe­knownst to par­tic­i­pants, iden­ti­cal. Impor­tant­ly, this task entire­ly removed poten­tial con­founds of vary­ing evi­dence in the stim­u­lus or vary­ing accu­ra­cy. We found that high­er pres­tim­u­lus alpha pow­er cor­re­lat­ed with low­er con­fi­dence in pitch dis­crim­i­na­tion. These results demon­strate that the rela­tion­ship of pres­tim­u­lus alpha pow­er and deci­sion con­fi­dence is direct in nature and, that it shows up in the audi­to­ry modal­i­ty sim­i­lar to what has been shown before in vision and somatosen­sa­tion. Our find­ings sup­port the view that low­er pres­tim­u­lus alpha pow­er enhances neur­al base­line excitability.

The paper is avail­able as preprint here.

Categories
Attention Auditory Cortex Brain stimulation Papers Perception Publications

New paper in press in JASA: Kre­it­e­wolf et al. on the role of voice-fea­ture con­ti­nu­ity for cock­tail-par­ty listening

Oble­ser­lab post­doc Jens Kre­it­e­wolf is in press in The Jour­nal of the Acousti­cal Soci­ety of America!

Togeth­er with our col­leagues, Marc Schön­wies­ner (Montreal/Leipzig), Samuel Math­ias (Yale), and Régis Tra­peau (Montreal/Marseille), we inves­ti­gat­ed the roles of two of the most salient voice fea­tures, glot­tal-pulse rate (GPR) and vocal-tract length (VTL), for per­cep­tu­al group­ing in the cock­tail par­ty. Using care­ful­ly con­trolled stim­uli, we show that lis­ten­ers exploit con­ti­nu­ity in both voice fea­tures to solve the cock­tail-par­ty prob­lem, but that VTL con­ti­nu­ity plays a stronger role for per­cep­tu­al group­ing than GPR con­ti­nu­ity. Our find­ings are in line with the dif­fer­en­tial impor­tance of VTL and GPR for the iden­ti­fi­ca­tion of nat­ur­al talk­ers and have clin­i­cal­ly rel­e­vant impli­ca­tions for cock­tail-par­ty lis­ten­ing in cochlear-implant users.

Data were record­ed using the Dome at BRAMS dur­ing Jens’ ACN Eras­mus Mundus exchange in Montreal.

The paper is avail­able as preprint:

https://www.biorxiv.org/content/early/2018/07/30/379545

 

Categories
Adaptive Control Auditory Cortex Auditory Neuroscience Auditory Working Memory Neural Oscillations Papers Perception Psychology Uncategorized

New paper in The Jour­nal of Neu­ro­science: Wilsch et al.., Tem­po­ral expec­ta­tion mod­u­lates the cor­ti­cal dynam­ics of short-term memory

Con­grat­u­la­tions to Oble­ser­lab alum­na Anna Wilsch, who is – for now – leav­ing acad­e­mia on a true high with her lat­est offer­ing on how tem­po­ral expec­ta­tions (“fore­knowl­edge” about when some­thing is to hap­pen) shape the neur­al make-up of memory!

Record­ed while the Oble­ser­lab was still in Leipzig at the Max Planck, and analysed with great input from our co-authors Mol­ly Hen­ry, Björn Her­rmann as well as Christoph Her­rmann (Old­en­burg), Anna used Mag­ne­toen­cephalog­ra­phy in an intri­cate but ulti­mate­ly very sim­ple sen­so­ry-mem­o­ry paradigm.

 

While sen­so­ry mem­o­ries of the phys­i­cal world fade quick­ly, Anna here shows that this decay of short-term mem­o­ry can be coun­ter­act­ed by tem­po­ral expectation.

Notably, spa­tial­ly dis­trib­uted cor­ti­cal pat­terns of alpha (8−−13 Hz) pow­er showed oppos­ing effects in audi­to­ry vs. visu­al sen­so­ry cor­tices. More­over, alpha-tuned con­nec­tiv­i­ty changes with­in supramodal atten­tion net­works reflect the allo­ca­tion of neur­al resources as short-term mem­o­ry rep­re­sen­ta­tions fade.

— to be updat­ed as the paper will become avail­able online –

Categories
Auditory Cortex Auditory Perception Auditory Speech Processing Hearing Loss Papers Perception Publications Speech

New paper in Ear and Hear­ing: Erb, Lud­wig, Kunke, Fuchs & Obleser on speech com­pre­hen­sion with a cochlear implant

We are excit­ed to share the results from our col­lab­o­ra­tion with the Cochlea Implant Cen­ter Leipzig: AC post­doc Julia Erb’s new paper on how 4‑Hz mod­u­la­tion sen­si­tiv­i­ty can inform us on 6‑month speech com­pre­hen­sion out­come in cochlear implants.

Erb J, Lud­wig AA, Kunke D, Fuchs M, & Obleser J (2018). Tem­po­ral sen­si­tiv­i­ty mea­sured short­ly after cochlear implan­ta­tion pre­dicts six-month speech recog­ni­tion outcome

Now avail­able online:

https://insights.ovid.com/crossref?an=00003446–900000000-98942

Abstract:

Objec­tives:

Psy­choa­coustic tests assessed short­ly after cochlear implan­ta­tion are use­ful pre­dic­tors of the reha­bil­i­ta­tive speech out­come. While large­ly inde­pen­dent, both spec­tral and tem­po­ral res­o­lu­tion tests are impor­tant to pro­vide an accu­rate pre­dic­tion of speech recog­ni­tion. How­ev­er, rapid tests of tem­po­ral sen­si­tiv­i­ty are cur­rent­ly lack­ing. Here, we pro­pose a sim­ple ampli­tude mod­u­la­tion rate dis­crim­i­na­tion (AMRD) par­a­digm that is val­i­dat­ed by pre­dict­ing future speech recog­ni­tion in adult cochlear implant (CI) patients.

Design:

In 34 new­ly implant­ed patients, we used an adap­tive AMRD par­a­digm, where broad­band noise was mod­u­lat­ed at the speech-rel­e­vant rate of ~4 Hz. In a lon­gi­tu­di­nal study, speech recog­ni­tion in qui­et was assessed using the closed-set Freiburg­er num­ber test short­ly after cochlear implan­ta­tion (t0) as well as the open-set Freiburg­er mono­syl­lab­ic word test 6 months lat­er (t6).

Results:

Both AMRD thresh­olds at t0 (r = –0.51) and speech recog­ni­tion scores at t0 (r = 0.56) pre­dict­ed speech recog­ni­tion scores at t6. How­ev­er, AMRD and speech recog­ni­tion at t0 were uncor­re­lat­ed, sug­gest­ing that those mea­sures cap­ture par­tial­ly dis­tinct per­cep­tu­al abil­i­ties. A mul­ti­ple regres­sion mod­el pre­dict­ing 6‑month speech recog­ni­tion out­come with deaf­ness dura­tion and speech recog­ni­tion at t0 improved from adjust­ed R2 = 0.30 to adjust­ed R2 = 0.44 when AMRD thresh­old was added as a predictor.

Con­clu­sions:

These find­ings iden­ti­fy AMRD thresh­olds as a reli­able, nonre­dun­dant pre­dic­tor above and beyond estab­lished speech tests for CI out­come. This AMRD test could poten­tial­ly be devel­oped into a rapid clin­i­cal tem­po­ral-res­o­lu­tion test to be inte­grat­ed into the post­op­er­a­tive test bat­tery to improve the reli­a­bil­i­ty of speech out­come prognosis.

 

Categories
Auditory Cortex Brain stimulation Papers Psychology Publications

New paper in press at eNeu­ro: Herb­st, Fiedler and Obleser on track­ing tem­po­ral haz­ard in the human EEG

Here, we show that human par­tic­i­pants use implic­it mod­u­la­tions of  tem­po­ral haz­ard, the prob­a­bil­i­ty of an item to occur at a cer­tain moment in time giv­en it has not yet occurred, when per­form­ing a pitch dis­crim­i­na­tion task. Using an encod­ing mod­el approach allows us to iso­late the track­ing of  tem­po­ral haz­ard by the time domain EEG sig­nal, notably by the sup­ple­men­tary motor area, a region known for its impli­ca­tion in timing.

The paper is avail­able as preprint:

https://www.biorxiv.org/content/early/2017/12/14/233551

Herb­st SK, Fiedler L & Obleser J (2018), Track­ing tem­po­ral haz­ard in the human elec­troen­cephalo­gram using a for­ward encod­ing mod­el. eNeu­ro (in press). 

Categories
Attention Auditory Cortex Auditory Perception Brain stimulation Papers Psychology Publications Speech

New paper in press in Brain Stim­u­la­tion: Wöst­mann, Vosskuhl, Obleser, and Her­rmann demon­strate that exter­nal­ly ampli­fied oscil­la­tions affect audi­to­ry spa­tial attention

In a fine col­lab­o­ra­tion we com­bine exper­tise on audi­to­ry cog­ni­tion (Malte Wöst­mann & Jonas Obleser, Uni­ver­si­ty of Lübeck) and brain stim­u­la­tion (Johannes Vosskuhl and Christoph S Her­rmann, Uni­ver­si­ty of Old­en­burg) to show that exter­nal­ly stim­u­lat­ed alpha and gam­ma oscil­la­tions dif­fer­en­tial­ly affect spa­tial atten­tion to speech. Our par­tic­i­pants per­formed a dichot­ic lis­ten­ing task while being stim­u­lat­ed using tran­scra­nial alter­nat­ing cur­rent stim­u­la­tion (tACS) at alpha or gam­ma fre­quen­cy (vs sham) on the left hemi­sphere. Alpha-tACS rel­a­tive­ly decreased recall of tar­gets con­tralat­er­al to stim­u­la­tion, while gam­ma-tACS reversed this effect. These results sug­gest that exter­nal­ly ampli­fied oscil­la­tions are func­tion­al­ly rel­e­vant to spa­tial attention.

Wöst­mann, M., Vosskuhl, J., Obleser, J., & Her­rmann, C.S. (2018). Oppo­site effects of lat­er­alised tran­scra­nial alpha ver­sus gam­ma stim­u­la­tion on audi­to­ry spa­tial attention.

Now avail­able online:

https://www.sciencedirect.com/science/article/pii/S1935861X18301074

Abstract:

Back­ground: Spa­tial atten­tion rel­a­tive­ly increas­es the pow­er of neur­al 10-Hz alpha oscil­la­tions in the hemi­sphere ipsi­lat­er­al to atten­tion, and decreas­es alpha pow­er in the con­tralat­er­al hemi­sphere. For gam­ma oscil­la­tions (>40 Hz), the oppo­site effect has been observed. The func­tion­al roles of lat­er­alised oscil­la­tions for atten­tion are cur­rent­ly unclear.

Hypoth­e­sis: If lat­er­alised oscil­la­tions are func­tion­al­ly rel­e­vant for atten­tion, tran­scra­nial stim­u­la­tion of alpha ver­sus gam­ma oscil­la­tions in one hemi­sphere should dif­fer­en­tial­ly mod­u­late the accu­ra­cy of spa­tial atten­tion to the ipsi-ver­sus con­tralat­er­al side.

Meth­ods: 20 human par­tic­i­pants per­formed a dichot­ic lis­ten­ing task under con­tin­u­ous tran­scra­nial alter­nat­ing cur­rent stim­u­la­tion (tACS, vs sham) at alpha (10 Hz) or gam­ma (47 Hz) fre­quen­cy. On each tri­al, par­tic­i­pants attend­ed to four spo­ken num­bers on the left or right ear, while ignor­ing num­bers on the oth­er ear. In order to stim­u­late a left tem­poro-pari­etal cor­tex region, which is known to show marked mod­u­la­tions of alpha pow­er dur­ing audi­to­ry spa­tial atten­tion, tACS (1 mA peak-to-peak ampli­tude) was applied at elec­trode posi­tions TP7 and FC5 over the left hemisphere.

Results: As pre­dict­ed, uni­hemi­spher­ic alpha-tACS rel­a­tive­ly decreased the recall of tar­gets con­tralat­er­al to stim­u­la­tion, but increased recall of ipsi­lat­er­al tar­gets. Impor­tant­ly, this spa­tial pat­tern of results was reversed for gamma-tACS.

Con­clu­sions: Results pro­vide a proof of con­cept that tran­scra­nial­ly stim­u­lat­ed oscil­la­tions can enhance spa­tial atten­tion and facil­i­tate atten­tion­al selec­tion of speech. Fur­ther­more, oppo­site effects of alpha ver­sus gam­ma stim­u­la­tion sup­port the view that states of high alpha are incom­men­su­rate with active neur­al pro­cess­ing as reflect­ed by states of high gamma.

Categories
Ageing Auditory Cortex Events Perception Psychology

Sym­po­sium at PuG 2018

Dur­ing the upcom­ing meet­ing of “Psy­chol­o­gy and the Brain 2018”, PhD stu­dent Leo Waschke will be host­ing a sym­po­sium on states and traits of neur­al activ­i­ty and their func­tion­al rel­e­vance for per­cep­tion and age­ing. Togeth­er with Lin­da Geerligs (Don­ders Insti­tute, NL), Marieke Schölvinck (ESI, Frank­furt) and Niels Kloost­er­man (MPIB, Berlin) he will be address­ing fluc­tu­a­tions in brain activ­i­ty on a host of timescales from mil­lisec­onds to min­utes. We are look­ing for­ward to meet­ing you in Giessen.

Categories
Auditory Cortex Auditory Neuroscience Brain stimulation Clinical relevance Degraded Acoustics Hearing Loss Neural Oscillations Neural Phase Papers Psychology Speech

New paper in press with the Old­en­burg brain-stim­u­la­tion crew!

AC alum­na Anna Wilsch has a new paper in press in Neu­roim­age, with Toralf Neul­ing, Jonas Obleser, and Christoph Her­rmann: “Tran­scra­nial alter­nat­ing cur­rent stim­u­la­tion with speech envelopes mod­u­lates speech com­pre­hen­sion”. In this proof-of-concept–like paper, we demon­strate that using the speech enve­lope as a “pilot sig­nal” for elec­tri­cal­ly stim­u­lat­ing the human brain, while a lis­ten­er tries to com­pre­hend that speech sig­nal buried in noise, does mod­u­late the listener’s speech–in–noise com­pre­hen­sion abilities.

The Preprint is here, … 

… while the abstract goes like this:
Cor­ti­cal entrain­ment of the audi­to­ry cor­tex to the broad­band tem­po­ral enve­lope of a speech sig­nal is cru­cial for speech com­pre­hen­sion. Entrain­ment results in phas­es of high and low neur­al excitabil­i­ty, which struc­ture and decode the incom­ing speech sig­nal. Entrain­ment to speech is strongest in the theta fre­quen­cy range (4−8 Hz), the aver­age fre­quen­cy of the speech enve­lope. If a speech sig­nal is degrad­ed, entrain­ment to the speech enve­lope is weak­er and speech intel­li­gi­bil­i­ty declines. Besides per­cep­tu­al­ly evoked cor­ti­cal entrain­ment, tran­scra­nial alter­nat­ing cur­rent stim­u­la­tion (tACS) entrains neur­al oscil­la­tions by apply­ing an elec­tric sig­nal to the brain. Accord­ing­ly, tACS-induced entrain­ment in audi­to­ry cor­tex has been shown to improve audi­to­ry per­cep­tion. The aim of the cur­rent study was to mod­u­late speech intel­li­gi­bil­i­ty exter­nal­ly by means of tACS such that the elec­tric cur­rent cor­re­sponds to the enve­lope of the pre­sent­ed speech stream (i.e., enve­lope-tACS). Par­tic­i­pants per­formed the Old­en­burg sen­tence test with sen­tences pre­sent­ed in noise in com­bi­na­tion with enve­lope-tACS. Crit­i­cal­ly, tACS was induced at time lags of 0 to 250 ms in 50-ms steps rel­a­tive to sen­tence onset (audi­to­ry stim­uli were simul­ta­ne­ous to or pre­ced­ed tACS). We per­formed sin­gle- sub­ject sinu­soidal, lin­ear, and qua­drat­ic fits to the sen­tence com­pre­hen­sion per­for­mance across the time lags. We could show that the sinu­soidal fit described the mod­u­la­tion of sen­tence com­pre­hen­sion best. Impor­tant­ly, the aver­age fre­quen­cy of the sinu­soidal fit was 5.12 Hz, cor­re­spond­ing to the peaks of the ampli­tude spec­trum of the stim­u­lat­ed envelopes. This find­ing was sup­port­ed by a sig­nif­i­cant 5‑Hz peak in the aver­age pow­er spec­trum of indi­vid­ual per­for­mance time series. Alto­geth­er, enve­lope tACS mod­u­lates intel­li­gi­bil­i­ty of speech in noise, pre­sum­ably by enhanc­ing and dis­rupt­ing (time lag with in- or out-of-phase stim­u­la­tion, respec­tive­ly) cor­ti­cal entrain­ment to the speech enve­lope in audi­to­ry cortex.