Categories
Attention Memory Papers

New Paper in Sci­en­tif­ic Reports by Lui&Wöstmann

A tick­ing clock in the liv­ing room; an ambi­ent music in the café; the foot­steps of a passers­by on the street – We are sur­round­ed by a pletho­ra of dis­tract­ing events with reg­u­lar tem­po­ral struc­tures in dai­ly life. Can we ignore these dis­trac­tors better?

Tro­by Ka-Yan Lui and Malte Wöst­mann recent­ly pub­lished a study on the effect of tem­po­ral­ly reg­u­lar ver­sus irreg­u­lar dis­trac­tors on the abil­i­ty to main­tain items in mem­o­ry. Sur­pris­ing­ly, they found that the tem­po­ral reg­u­lar­i­ty of dis­trac­tors did not have an effect on participant’s mem­o­ry per­for­mance. Instead, they found an effect of the tem­po­ral reg­u­lar­i­ty of dis­trac­tors on response behav­iour – par­tic­i­pants were faster and more biased in respond­ing whether the cur­rent num­ber matched with the num­ber in memory.

These results have the­o­ret­i­cal impli­ca­tions: exter­nal dis­trac­tion may have a more per­va­sive influ­ence on dif­fer­ent aspects of cog­ni­tive process­es than mem­o­ry main­te­nance. The arti­cle will soon be avail­able in Sci­en­tif­ic Reports.

Categories
Attention fMRI Memory Papers

New paper in Neu­roIm­age, Lim et al.

Atten­tion lets us focus our lim­it­ed cog­ni­tive resources on behav­ioral­ly impor­tant infor­ma­tion. Less obvi­ous is that atten­tion also helps us to hold infor­ma­tion in mem­o­ry with high pre­ci­sion. But how does the brain imple­ment this direct­ed atten­tion to mem­o­ry, and what behav­iour­al ben­e­fits does it yield for us humans?

For­mer post­doc Sung-Joo Lim (now at Bing­ham­ton Uni­ver­si­ty), Jonas Obleser, and a team of col­lab­o­ra­tors from Old­en­burg (Chris­tiane Thiel) and Leipzig (Bern­hard Sehm, Lorenz Deser­no, and Jöran Lep­sien) have now a new arti­cle on this old prob­lem, to appear in NeuroImage.

Using the changes in brain blood oxy­gena­tion as mea­sured with fMRI, this study demon­strates that atten­tion enables mem­o­ry main­te­nance of speech sound infor­ma­tion across mul­ti­ple brain regions. A speech-sen­si­tive brain region in the tem­po­ral lobe (the left supe­ri­or tem­po­ral sul­cus) con­tributes the most in pre­dict­ing the indi­vid­ual gain in recall pre­ci­sion of audi­to­ry objects from mem­o­ry. This study high­lights that func­tion­al­ly dis­crete brain regions work togeth­er in main­tain­ing and atten­tion­al­ly enhanc­ing work­ing mem­o­ry infor­ma­tion, but they exert dif­ferental influ­ences depend­ing on their func­tion­al specializations.

The full arti­cle is now avail­able here.

Categories
Adaptive Control Attention EEG / MEG Neural dynamics Papers Uncategorized

New paper in eLife, Waschke et al.

For­mer Oble­ser­lab PhD stu­dent Leo Waschke is now out in eLife with an inge­nious demon­stra­tion how both endoge­nous and exoge­nous­ly-dri­ven changes in the steep­ness of the brain-elec­tric 1/f pow­er spec­trum (in part linked direct­ly to local excitation:inhibiton, E:I, ratio) in neur­al pop­u­la­tions can affect behav­iour in com­plex, mul­ti-sen­so­ry envi­ron­ments: “Modal­i­ty-spe­cif­ic track­ing of atten­tion and sen­so­ry sta­tis­tics in the human elec­tro­phys­i­o­log­i­cal spec­tral expo­nent”

The results draw heav­i­ly on the recent spec­tral-slope expo­nent work by our col­lab­o­ra­tors at Uni­ver­si­ty of Cal­i­for­nia San Diego in the lab of Bradley Voytek, and have come togeth­er in a three-lab col­labo of Lübeck, San Diego, and Leo’s cur­rent sci­en­tif­ic home, the Dou­glas Gar­rett lab at the MPIB.

 
Con­grat­u­la­tions, Leo!

Categories
Attention Auditory Neuroscience EEG / MEG Papers Publications Speech Tracking Unilateral Vocoding

New Paper in Trends in Hear­ing by Kraus et al.

Frauke Kraus, Sarah Tune, Anna Ruhe, Jonas Obleser & Malte Wöst­mann demon­strate that uni­lat­er­al acoustic degra­da­tion delays atten­tion­al sep­a­ra­tion of com­pet­ing speech.

Uni­lat­er­al cochlear implant (CI) users have to inte­grate acousti­cal­ly intact speech on one ear and acousti­cal­ly degrad­ed speech on the oth­er ear. How inter­act uni­lat­er­al acoustic degra­da­tion and spa­tial atten­tion in a mul­titalk­er situation?
N = 22 par­tic­i­pants took part in a com­pet­ing lis­ten­ing exper­i­ment while lis­ten­ing to an intact audio­book under dis­trac­tion of an acousti­cal­ly degrad­ed audio­book and vice ver­sa. Speech track­ing revealed not per se reduced atten­tion­al sep­a­ra­tion of acousti­cal­ly degrad­ed speech but instead a delay in time com­pared to intact speech. These find­ings might explain lis­ten­ing chal­lenges expe­ri­enced by uni­lat­er­al CI users.

To learn more, the paper is avail­able here.

Categories
Attention Auditory Neuroscience Neural Oscillations Papers Psychology Uncategorized

New paper in press in the Jour­nal of Neuroscience

Wöst­mann, Alavash and Obleser demon­strate that alpha oscil­la­tions in the human brain imple­ment dis­trac­tor sup­pres­sion inde­pen­dent of tar­get selection.

In the­o­ry, the abil­i­ty to selec­tive­ly focus on rel­e­vant objects in our envi­ron­ment bases on selec­tion of tar­gets and sup­pres­sion of dis­trac­tion. As it is unclear whether tar­get selec­tion and dis­trac­tor sup­pres­sion are inde­pen­dent, we designed an Elec­troen­cephalog­ra­phy (EEG) study to direct­ly con­trast these two processes.

Par­tic­i­pants per­formed a pitch dis­crim­i­na­tion task on a tone sequence pre­sent­ed at one loud­speak­er loca­tion while a dis­tract­ing tone sequence was pre­sent­ed at anoth­er loca­tion. When the dis­trac­tor was fixed in the front, atten­tion to upcom­ing tar­gets on the left ver­sus right side induced hemi­spher­ic lat­er­al­i­sa­tion of alpha pow­er with rel­a­tive­ly high­er pow­er ipsi- ver­sus con­tralat­er­al to the side of attention.

Crit­i­cal­ly, when the tar­get was fixed in front, sup­pres­sion of upcom­ing dis­trac­tors reversed the pat­tern of alpha lat­er­al­i­sa­tion, that is, alpha pow­er increased con­tralat­er­al to the dis­trac­tor and decreased ipsi­lat­er­al­ly. Since the two lat­er­al­ized alpha respons­es were uncor­re­lat­ed across par­tic­i­pants, they can be con­sid­ered large­ly inde­pen­dent cog­ni­tive mechanisms.

This was fur­ther sup­port­ed by the fact that alpha lat­er­al­i­sa­tion in response to dis­trac­tor sup­pres­sion orig­i­nat­ed in more ante­ri­or, frontal cor­ti­cal regions com­pared with tar­get selec­tion (see figure).

The paper is also avail­able as preprint here.

 

Categories
Adaptive Control Attention fMRI Grants Hearing Loss Uncategorized

New DFG project led by Mohsen Alavash on the Net­work Neu­ro­science of Spa­tial Attention

Con­grat­u­la­tions to our cur­rent­ly ERC-fund­ed lab mem­ber and post­doc Mohsen Alavash who has just secured 3‑year fund­ing (~380,000 €) by the Deutsche Forschungs­ge­mein­schaft (DFG) for an ambi­tious project: Mohsen wants to get clos­er to a net­work/­graph-the­o­ret­i­cal descrip­tion of how spa­tial atten­tion in the lis­ten­ing brain is organ­ised. In a lat­er stage of the project, Mohsen also plans on study­ing how the net­work organ­i­sa­tion of spa­tial atten­tion may be altered in hear­ing-impaired listeners.

We are glad that Mohsen plans on run­ning this project with­in the Obleser lab, here at the Uni­ver­si­ty of Lübeck.

Also, make sure to check out Mohsen’s lat­est pub­li­ca­tion on the topic.

Categories
Attention Auditory Cortex Auditory Speech Processing EEG / MEG Psychology Speech

AC post­doc Malte Wöst­mann scores DFG grant to study the tem­po­ral dynam­ics of the audi­to­ry atten­tion­al filter

In this three-year project, we will use the audi­to­ry modal­i­ty as a test case to inves­ti­gate how the sup­pres­sion of dis­tract­ing infor­ma­tion (i.e., “fil­ter­ing”) is neu­ral­ly imple­ment­ed. While it is known that the atten­tion­al sam­pling of tar­gets (a) is rhyth­mic, (b) can be entrained, and © is mod­u­lat­ed by top-down pre­dic­tions, the exis­tence and neur­al imple­men­ta­tion of these mech­a­nisms for the sup­pres­sion of dis­trac­tors is at present unclear. To test this, we will use adap­ta­tions of estab­lished behav­iour­al par­a­digms of dis­trac­tor sup­pres­sion and record­ings of human elec­tro­phys­i­o­log­i­cal sig­nals in the Magen­to-/ Elec­troen­cephalo­gram (M/EEG).

Abstract of research project:

Back­ground: Goal-direct­ed behav­iour in tem­po­ral­ly dynam­ic envi­ron­ments requires to focus on rel­e­vant infor­ma­tion and to not get dis­tract­ed by irrel­e­vant infor­ma­tion. To achieve this, two cog­ni­tive process­es are nec­es­sary: On the one hand, atten­tion­al sam­pling of tar­get stim­uli has been focus of exten­sive research. On the oth­er hand, it is less well known how the human neur­al sys­tem exploits tem­po­ral infor­ma­tion in the stim­u­lus to fil­ter out dis­trac­tion. In the present project, we use the audi­to­ry modal­i­ty as a test case to study the tem­po­ral dynam­ics of atten­tion­al fil­ter­ing and its neur­al implementation.

Approach and gen­er­al hypoth­e­sis: In three vari­ants of the “Irrel­e­vant-Sound Task” we will manip­u­late tem­po­ral aspects of audi­to­ry dis­trac­tors. Behav­iour­al recall of tar­get stim­uli despite dis­trac­tion and respons­es in the elec­troen­cephalo­gram (EEG) will reflect the integri­ty and neur­al imple­men­ta­tion of the atten­tion­al fil­ter. In line with pre­lim­i­nary research, our gen­er­al hypoth­e­sis is that atten­tion­al fil­ter­ing bases on sim­i­lar but sign-reversed mech­a­nisms as atten­tion­al sam­pling: For instance, while atten­tion to rhyth­mic stim­uli increas­es neur­al sen­si­tiv­i­ty at time points of expect­ed tar­get occur­rence, fil­ter­ing of dis­trac­tors should instead decrease neur­al sen­si­tiv­i­ty at the time of expect­ed distraction.

Work pro­gramme: In each one of three Work Pack­ages (WPs), we will take as a mod­el an estab­lished neur­al mech­a­nism of atten­tion­al sam­pling and test the exis­tence and neur­al imple­men­ta­tion of a sim­i­lar mech­a­nism for atten­tion­al fil­ter­ing. This way, we will inves­ti­gate whether atten­tion­al fil­ter­ing fol­lows an intrin­sic rhythm (WP1), whether rhyth­mic dis­trac­tors can entrain atten­tion­al fil­ter­ing (WP2), and whether fore­knowl­edge about the time of dis­trac­tion induces top-down tun­ing of the atten­tion­al fil­ter in frontal cor­tex regions (WP3).

Objec­tives and rel­e­vance: The pri­ma­ry objec­tive of this research is to con­tribute to the foun­da­tion­al sci­ence on human selec­tive atten­tion, which requires a com­pre­hen­sive under­stand­ing of how the neur­al sys­tem achieves the task of fil­ter­ing out dis­trac­tion. Fur­ther­more, hear­ing dif­fi­cul­ties often base on dis­trac­tion by salient but irrel­e­vant sound. Results of this research will trans­late to the devel­op­ment of hear­ing aids that take into account neu­ro-cog­ni­tive mech­a­nisms to fil­ter out dis­trac­tion more efficiently.

Categories
Attention Auditory Cortex Auditory Speech Processing Papers Psychology Publications Speech

New paper in press in the Jour­nal of Cog­ni­tive Neuroscience

Wöst­mann, Schmitt and Obleser demon­strate that clos­ing the eyes enhances the atten­tion­al mod­u­la­tion of neur­al alpha pow­er but does not affect behav­iour­al per­for­mance in two lis­ten­ing tasks

Does clos­ing the eyes enhance our abil­i­ty to lis­ten atten­tive­ly? In fact, many of us tend to close their eyes when lis­ten­ing con­di­tions become chal­leng­ing, for exam­ple on the phone. It is thus sur­pris­ing that there is no pub­lished work on the behav­iour­al or neur­al con­se­quences of clos­ing the eyes dur­ing atten­tive lis­ten­ing. In the present study, we demon­strate that eye clo­sure does not only increase the over­all lev­el of absolute alpha pow­er but also the degree to which audi­to­ry atten­tion mod­u­lates alpha pow­er over time in syn­chrony with attend­ing to ver­sus ignor­ing speech. How­ev­er, our behav­iour­al results pro­vide evi­dence for the absence of any dif­fer­ence in lis­ten­ing per­for­mance with closed ver­sus open eyes. The like­ly rea­son for this is that the impact of eye clo­sure on neur­al oscil­la­to­ry dynam­ics does not match alpha pow­er mod­u­la­tions asso­ci­at­ed with lis­ten­ing per­for­mance pre­cise­ly enough (see figure).

The paper is avail­able as preprint here.