Cat­e­go­riz­ing sounds is vital for adap­tive human behav­ior. Accord­ing­ly, chang­ing lis­ten­ing sit­u­a­tions (exter­nal noise or periph­er­al hear­ing loss in aging) that may be accom­pa­nied by changes in dis­crim­inabil­i­ty, require lis­ten­ers to flex­i­bly adjust their cat­e­go­riza­tion strate­gies, some­times by changes in uti­liz­ing avail­able acoustic cues.
In this func­tion­al Mag­net­ic Res­o­nance Imag­ing (fMRI) study, we inves­ti­gate the cat­e­go­riza­tion of nov­el, non-speech audi­to­ry stim­uli that var­ied in over­all dis­crim­inabil­i­ty. More­over, we manip­u­late the rel­a­tive infor­ma­tive­ness of a dura­tion ver­sus a spec­tral-peak cue by adding spec­tral degra­da­tion in the mid­dle of the exper­i­ment. The results demon­strate dif­fer­ent roles of tem­po­ral and pari­etal brain areas for audi­to­ry cat­e­go­riza­tion: Tem­po­ral cor­tex acti­va­tion, in par­tic­u­lar in pos­te­ri­or parts of the right supe­ri­or tem­po­ral gyrus, scaled with dis­crim­inabil­i­ty, while left pari­etal cor­tex acti­va­tion was asso­ci­at­ed with changes in cue uti­liza­tion after the appli­ca­tion of spec­tral degradation.
This work extends pre­vi­ous research on audi­to­ry cat­e­go­riza­tion. Impor­tant­ly, the involve­ment of the left infe­ri­or pari­etal lob­ule in changes of cue uti­liza­tion sup­ports its role in domain-gen­er­al process­es that sup­port cat­e­go­riza­tion. Fur­ther, the sen­si­tiv­i­ty of the right pos­te­ri­or supe­ri­or tem­po­ral gyrus to stim­u­lus dis­crim­inabil­i­ty adds to pre­vi­ous find­ings regard­ing its role in audi­to­ry processing.