Tusch, Erich S.Alperin, Brittany R.Holcomb, Phillip J.Daffner, Kirk2016-12-022016Tusch, Erich S., Brittany R. Alperin, Phillip J. Holcomb, and Kirk R. Daffner. 2016. “Increased Early Processing of Task-Irrelevant Auditory Stimuli in Older Adults.” PLoS ONE 11 (11): e0165645. doi:10.1371/journal.pone.0165645. http://dx.doi.org/10.1371/journal.pone.0165645.1932-6203http://nrs.harvard.edu/urn-3:HUL.InstRepos:29625987The inhibitory deficit hypothesis of cognitive aging posits that older adults’ inability to adequately suppress processing of irrelevant information is a major source of cognitive decline. Prior research has demonstrated that in response to task-irrelevant auditory stimuli there is an age-associated increase in the amplitude of the N1 wave, an ERP marker of early perceptual processing. Here, we tested predictions derived from the inhibitory deficit hypothesis that the age-related increase in N1 would be 1) observed under an auditory-ignore, but not auditory-attend condition, 2) attenuated in individuals with high executive capacity (EC), and 3) augmented by increasing cognitive load of the primary visual task. ERPs were measured in 114 well-matched young, middle-aged, young-old, and old-old adults, designated as having high or average EC based on neuropsychological testing. Under the auditory-ignore (visual-attend) task, participants ignored auditory stimuli and responded to rare target letters under low and high load. Under the auditory-attend task, participants ignored visual stimuli and responded to rare target tones. Results confirmed an age-associated increase in N1 amplitude to auditory stimuli under the auditory-ignore but not auditory-attend task. Contrary to predictions, EC did not modulate the N1 response. The load effect was the opposite of expectation: the N1 to task-irrelevant auditory events was smaller under high load. Finally, older adults did not simply fail to suppress the N1 to auditory stimuli in the task-irrelevant modality; they generated a larger response than to identical stimuli in the task-relevant modality. In summary, several of the study’s findings do not fit the inhibitory-deficit hypothesis of cognitive aging, which may need to be refined or supplemented by alternative accounts.en-USPeople and PlacesPopulation GroupingsAge GroupsBiology and Life SciencesNeuroscienceSensory PerceptionVisionPsychologySocial SciencesCognitive ScienceCognitionElderlyBioassays and Physiological AnalysisElectrophysiological TechniquesBrain ElectrophysiologyElectroencephalographyEvent-Related PotentialsPhysiologyElectrophysiologyNeurophysiologyMedicine and Health SciencesBrain MappingDiagnostic MedicineClinical NeurophysiologyImaging TechniquesNeuroimagingCognitive NeuroscienceCognitive NeurologyNeuropsychological TestingNeurologyNeuropsychologyDevelopmental BiologyOrganism DevelopmentAgingPhysiological ProcessesCognitive PsychologyAttentionJournal Article2016-12-0210.1371/journal.pone.0165645