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]