Tag: categorization

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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
Papers Perception Publications

New Paper in press — Scharinger, Hen­ry, Obleser, in Mem­o­ry & Cognition

For nor­mal-hear­ing humans, cat­e­go­riz­ing com­plex acoustic stim­uli is a seem­ing­ly effort­less process, even if one has nev­er heard the par­tic­u­lar sounds before. Nev­er­the­less, pri­or expe­ri­ence with spe­cif­ic cor­re­la­tions between acoustic stim­u­lus prop­er­ties affects the cat­e­go­riza­tion in a ben­e­fi­cial way, as we show in our paper:

Pri­or expe­ri­ence with neg­a­tive spec­tral cor­re­la­tions pro­motes infor­ma­tion inte­gra­tion dur­ing audi­to­ry cat­e­go­ry learning

(by Math­ias Scharinger, Mol­ly Hen­ry, and Jonas Obleser).

The arti­cle is in press at Mem­o­ry & Cog­ni­tion (avail­able online). Our main find­ing is that stim­uli dif­fer­ing in the loca­tion of two spec­tral peaks were bet­ter cat­e­go­rized if there was a neg­a­tive cor­re­la­tion between the two spec­tral peaks than if there was a pos­i­tive cor­re­la­tion. Since neg­a­tive spec­tral cor­re­la­tions char­ac­ter­ize pho­net­ic speech prop­er­ties, our find­ings sug­gest that short-term audi­to­ry cat­e­go­ry learn­ing is influ­enced by long-term rep­re­sen­ta­tions of abstract acoustic-pho­net­ic prop­er­ties (here: spec­tral correlations).

Ref­er­ences

  • Scharinger M, Hen­ry MJ, Obleser J. Pri­or expe­ri­ence with neg­a­tive spec­tral cor­re­la­tions pro­motes infor­ma­tion inte­gra­tion dur­ing audi­to­ry cat­e­go­ry learn­ing. Mem Cog­nit. 2013 Jul;41(5):752–68. PMID: 23354998. [Open with Read]