web analytics

Category: Neural Oscillations

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.
Categories
Attention Auditory Neuroscience EEG / MEG Evoked Activity Neural Oscillations Neural Phase Papers Perception Psychology Uncategorized

New paper in Plos Biol­o­gy: Com­ment by Obleser, Hen­ry, & Lakatos

My col­leagues and col­lab­o­ra­tor Peter Lakatos and Mol­ly Hen­ry and I took to our desks and Mat­lab con­soles, when Assaf Bres­ka and Leon Deouell came out ear­li­er this year with their paper in Plos Biology.

We had a few things to say about what we then per­ceived as a rather pes­simistic assess­ment of neur­al entrain­ment. How­ev­er, since then a great and quite fru­ti­ful dis­cus­sion has emerged, now pub­lished in Plos Biology:

Obleser J, Hen­ry, MJ, & Lakatos, P. What do we talk about when we talk about rhythm?, Plos Biol­o­gy 2017

Mean­while, Bres­ka and Deouell added some more behav­iour­al data and replied to us (now also pub­lished).

— Enjoy!

 

Categories
Adaptive Control Ageing Auditory Cortex Auditory Neuroscience EEG / MEG Evoked Activity Executive Functions Neural Oscillations Neural Phase Papers Perception Publications

New paper in press: Hen­ry et al., Nature Communications

Here comes a new paper in Nature Com­mu­ni­ca­tions by for­mer AC post­doc Mol­ly Hen­ry, with for­mer fel­low post­doc AC alum­nus Björn Her­rmann, our tire­less lab man­ag­er, Dun­ja Kunke, and myself! It is a late (to us quite impor­tant) result from our lab’s tenure at the Max Planck in Leipzig, 

Hen­ry, M.J., Her­rmann, B., Kunke, D., Obleser, J. (In press). Aging affects the bal­ance of neur­al entrain­ment and top-down neur­al mod­u­la­tion in the lis­ten­ing brain. Nature Communications. 

—Con­grat­u­la­tions, Molly!

Categories
Adaptive Control Attention Auditory Cortex Auditory Neuroscience Auditory Perception Auditory Speech Processing Degraded Acoustics EEG / MEG Evoked Activity Executive Functions Neural Oscillations Noise-Vocoded Speech Papers Perception Psychology Publications Speech

New paper in press in Cere­bral Cor­tex: Wöst­mann et al. on ignor­ing degrad­ed speech

Audi­to­ry Cognition’s own Malte Wöst­mann is in press in Cere­bral Cor­tex with his lat­est offer­ing on how atten­tion­al con­trol man­i­fests in alpha pow­er changes: Ignor­ing speech can be ben­e­fi­cial (if com­pre­hend­ing speech poten­tial­ly detracts from anoth­er task), and we here show how this change in lis­ten­ing goals turns around the pat­tern of alpha-pow­er changes with chang­ing speech degra­da­tion. (We will update as the paper becomes avail­able online.)

Wöst­mann, M., Lim, S.J., & Obleser, J. (2017). The human neur­al alpha response to speech is a proxy of atten­tion­al con­trol. Cere­bral Cor­tex. In press.

 

Abstract
Human alpha (~10 Hz) oscil­la­to­ry pow­er is a promi­nent neur­al mark­er of cog­ni­tive effort. When lis­ten­ers attempt to process and retain acousti­cal­ly degrad­ed speech, alpha pow­er enhances. It is unclear whether these alpha mod­u­la­tions reflect the degree of acoustic degra­da­tion per se or the degra­da­tion-dri­ven demand to a listener’s atten­tion­al con­trol. Using an irrel­e­vant-speech par­a­digm in elec­troen­cephalog­ra­phy (EEG), the cur­rent exper­i­ment demon­strates that the neur­al alpha response to speech is a sur­pris­ing­ly clear proxy of top-down con­trol, entire­ly dri­ven by the lis­ten­ing goals of attend­ing ver­sus ignor­ing degrad­ed speech. While (n=23) lis­ten­ers retained the ser­i­al order of 9 to-be-recalled dig­its, one to-be-ignored sen­tence was pre­sent­ed. Dis­tractibil­i­ty of the to-be-ignored sen­tence para­met­ri­cal­ly var­ied in acoustic detail (noise-vocod­ing), with more acoustic detail of dis­tract­ing speech increas­ing­ly dis­rupt­ing lis­ten­ers’ ser­i­al mem­o­ry recall. Where pre­vi­ous stud­ies had observed decreas­es in pari­etal and audi­to­ry alpha pow­er with more acoustic detail (of tar­get speech), alpha pow­er here showed the oppo­site pat­tern and increased with more acoustic detail in the speech dis­trac­tor. In sum, the neur­al alpha response reflects almost exclu­sive­ly a listener’s exer­tion of atten­tion­al con­trol, which is deci­sive for whether more acoustic detail facil­i­tates com­pre­hen­sion (of attend­ed speech) or enhances dis­trac­tion (of ignored speech).
Categories
EEG / MEG Neural Oscillations Papers Perception Publications

New paper in press: Alavash et al. in Net­work Neuroscience

We are proud to pub­lish our recent study on how net­work dynam­ics of beta-band oscil­la­tions in the human brain medi­ate response speed in audi­to­ry per­cep­tu­al deci­sion-mak­ing. This work will appear soon in the first vol­ume of the promis­ing jour­nal Net­work Neu­ro­science.

Pre-print link http://biorxiv.org/content/early/2016/12/19/095356

Abstract
Per­cep­tu­al deci­sions vary in the speed at which we make them. Evi­dence sug­gests that trans­lat­ing sen­so­ry infor­ma­tion into behav­ioral deci­sions relies on dis­trib­uted inter­act­ing neur­al pop­u­la­tions, with deci­sion speed hing­ing on pow­er mod­u­la­tions of neur­al oscil­la­tions. Yet, the depen­dence of per­cep­tu­al deci­sions on the large-scale net­work orga­ni­za­tion of cou­pled neur­al oscil­la­tions has remained elu­sive. We mea­sured mag­ne­toen­cephalog­ra­phy sig­nals in human lis­ten­ers who judged acoustic stim­uli made of care­ful­ly titrat­ed clouds of tone sweeps. These stim­uli were used under two task con­texts where the par­tic­i­pants judged the over­all pitch or direc­tion of the tone sweeps. We traced the large-scale net­work dynam­ics of source-pro­ject­ed neur­al oscil­la­tions on a tri­al-by-tri­al basis using pow­er enve­lope cor­re­la­tions and graph-the­o­ret­i­cal net­work dis­cov­ery. Under both tasks, faster deci­sions were pre­dict­ed by high­er seg­re­ga­tion and low­er inte­gra­tion of cou­pled beta-band (~16–28 Hz) oscil­la­tions. We also uncov­ered brain net­work states that pro­mot­ed faster deci­sions and emerged from low­er-order audi­to­ry and high­er-order con­trol brain areas. Specif­i­cal­ly, deci­sion speed in judg­ing tone-sweep direc­tion crit­i­cal­ly relied on nodal net­work con­fig­u­ra­tions of ante­ri­or tem­po­ral, cin­gu­late and mid­dle frontal cor­tices. Our find­ings sug­gest that glob­al net­work com­mu­ni­ca­tion dur­ing per­cep­tu­al deci­sion-mak­ing is imple­ment­ed in the human brain by large-scale cou­plings between beta-band neur­al oscillations.
Categories
Auditory Cortex Auditory Neuroscience Editorial Notes Neural Oscillations Papers Psychology

Sto­ry time: Hen­ry & Obleser (2012) revisited

Sto­ry time: Some time in ear­ly 2011, I sat down with an Amer­i­can, fresh PhD grad­u­ate who had just joined my new lab, in a Leipzig bar (Café Can­tona; if you are inter­est­ed you can find this great 24⁄7 bar with exquis­ite food also in the acknowl­edg­ments of, e.g., Obleser & Eis­ner, Trends Cogn Sci, 2009).
To the day, I could still point you to the table she and I sat down at, and the wall I faced (which is notable because we actu­al­ly spent an unhealthy amount of time and mon­ey there over the years). Soon there­after, we grabbed a beer mat and start­ed scrib­bling waves and marked where we would place so-called tar­gets (psy­chol­o­gist lin­go) and talked a lot of gib­ber­ish about fre­quen­cy mod­u­la­tion. I remem­ber vidid­ly that I had just read an insane­ly long review paper on neur­al oscil­la­tions by Wolf­gang Klimesch (that, more in pass­ing, cit­ed old-school tales of Schmitt fil­ters by the late great Francesco Varela or pio­neers  sound­ing like record pro­duc­ers, Dust­man & Beck, 1965), while the young Amer­i­can oppo­site me turned out to be an—if adventurous—die-hard expert on audi­to­ry psychophysics.

Who would have thought that this very night would car­ry me towards tenure in three years’ time, and her around the globe as an esteemed young colleague.
When I nowa­days check Google schol­ar, I am amazed to see that already more than 100 oth­er papers have cit­ed what direct­ly grew out of that beer mat one and a half years later—not count­ing the many more papers this said post­doc, Mol­ly Hen­ry, has pro­duced since.

Here is the link to how excit­ed we were when the paper appeared in PNAS in 2012, and a link to the lit­tle movie a ger­man sci­ence pro­gram kind­ly pro­duced on all of this in 2013.

Categories
Auditory Cortex Auditory Perception Cross-Modal Integration EEG / MEG Neural Oscillations Perception

New paper out: Plöchl, Gas­ton, Mer­ma­gen, König & Hair­ston, Sci­en­tif­ic Reports

An arti­cle by our new AC group mem­ber Michael Plöchl from his PhD project in Osnabrück has been accept­ed for pub­li­ca­tion in Sci­en­tif­ic Reports. In their study, Plöchl, Gas­ton, Mer­ma­gen, König and Hair­ston demon­strate that “Oscil­la­to­ry activ­i­ty in audi­to­ry cor­tex reflects the per­cep­tu­al lev­el of audio-tac­tile integration”.

oscillatory_activity

Abstract
Cross-modal inter­ac­tions between sen­so­ry chan­nels have been shown to depend on both the spa­tial dis­par­i­ty and the per­cep­tu­al sim­i­lar­i­ty between the pre­sent­ed stim­uli. Here we inves­ti­gate the behav­ioral and neur­al inte­gra­tion of audi­to­ry and tac­tile stim­u­lus pairs at dif­fer­ent lev­els of spa­tial dis­par­i­ty. Addi­tion­al­ly, we mod­u­lat­ed the ampli­tudes of both stim­uli in either a coher­ent or non-coher­ent man­ner. We found that both audi­to­ry and tac­tile local­iza­tion per­for­mance was biased towards the stim­u­lus in the respec­tive oth­er modal­i­ty. This bias lin­ear­ly increas­es with stim­u­lus dis­par­i­ty and is more pro­nounced for coher­ent­ly mod­u­lat­ed stim­u­lus pairs. Analy­ses of elec­troen­cephalo­graph­ic (EEG) activ­i­ty at temporal–cortical sources revealed enhanced event-relat­ed poten­tials (ERPs) as well as decreased alpha and beta pow­er dur­ing bimodal as com­pared to uni­modal stim­u­la­tion. How­ev­er, while the observed ERP dif­fer­ences are sim­i­lar for all stim­u­lus com­bi­na­tions, the extent of oscil­la­to­ry desyn­chro­niza­tion varies with stim­u­lus dis­par­i­ty. More­over, when both stim­uli were sub­jec­tive­ly per­ceived as orig­i­nat­ing from the same direc­tion, the reduc­tion in alpha and beta pow­er was sig­nif­i­cant­ly stronger. These obser­va­tions sug­gest that in the EEG the lev­el of per­cep­tu­al inte­gra­tion is main­ly reflect­ed by changes in ongo­ing oscil­la­to­ry activity.
Categories
Auditory Cortex Auditory Perception Media Neural Oscillations Papers Publications Uncategorized

New fea­turette in eLife: Tell me some­thing I don’t know

For those inter­est­ed in audi­to­ry cor­tex and how a regime of pre­dic­tions, pre­dic­tion updates and sur­prise (a ver­sion of “pre­dic­tion error”) might be imple­ment­ed there, I con­tributed a brief fea­turette (“insight”, they call it) to eLife on a recent paper by Will Sed­ley, Tim Grif­fiths, and oth­ers. Check it out.
Obleser-elife-Figure

[For those not so famil­iar with it, “eLife”, despite its aes­thet­i­cal­ly ques­tion­able name, pos­es an inter­est­ing and rel­a­tive­ly new, high-pro­file, open-access pub­lish­ing effort by nobel-prize-win­ning Randy Schek­man, for­mer SfN pres­i­dent Eve Marder and others.]