Selective Attention to Speech Occurs primarily โขin the Brain’sโข Cortex,New Research Finds
Recent research from the โUniversity of โฃMichigan has clarified โthe neural basis โขofโฃ selective attention โค-โ the ability โtoโ focus on one sound while filtering out others. โขUtilizing novel experimental techniques, scientists have found no evidenceโข that this process involves differential processing of sound atโข subcortical levels, specifically within the auditory nerve or โbrainstem.The findings indicate that selective attention to speech is โฃlargelyโ drivenโข by activity within the auditoryโค cortex.
Prior research on selective โขattention often โemployed artificial โคsounds, โฃlimiting โขits real-world applicability. This study, published โฃin PLOS โคBiology (Stoll, T. J., et al. 2025. doi.org/10.1371/journal.pbio.3003407), more closely mimicked a “cocktail party” scenario by having participants listen โto segments โฃfrom two audiobooks narratedโฃ by different โspeakers. Researchers measured responses from โthe auditory nerve, brainstem, and cortex while โparticipants listened to the audiobooks simultaneously, both in the same ear (dioticโฃ listening) and in opposite ears (dichotic listening).
The results consistentlyโ showed that theโ subcortical auditoryโ system responded to both attendedโ and ignored speech in the same manner. This contrasts with the cortex, which demonstrably “turns โup โthe volume” โฃon the sound a personโ is actively focusingโ on, according โขto Rossโ Maddox, โคPh.D., associate professor โof otolaryngology at โฃthe University ofโฃ michigan medical school โand โฃsenior author of the paper. Statistical analysis further supported the lack of subcorticalโข effects. A strong attention effect was observed within the cortex, aligning with previous studies.
The research team โฃacknowledges that a previous study had โyielded conflicting results, potentially due to variationsโฃ in experimental design. Thatโฃ earlier research utilized multiple stories per narrator, introducing potential confounding factors โคfrom “uncontrolled acoustic differences.” An โคadditional experiment conductedโ as part of this current study confirmed the potential influence โคof such design elements.
Researchers emphasizeโข that theโ absence ofโ observed subcortical effects does not definitivelyโ rule out their existence. It’s possible that subtle โsubcortical mechanisms, involving neurons currently beyond the scope ofโ measurement, contributeโ to selective โattention.
“What โคwe’ve shown here is that for โฃhumanโ studies,โ there is no โคsubcortical attention effect that canโ be measured with the tools we have โavailable,”โ explained Maddox. Theโ team developed new experimental โขmethods to address the long-standing โคdebate, and anticipates โคthat continued technological โadvancements may allowโ for more โdetailed examinationโ of the auditory brain in โคthe future.
Source: Michigan Medicine – University of โฃMichigan (https://www.michiganmedicine.org/)
