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Varghese, Leonard

Evidence against attentional state modulating scalp-recorded auditory brainstem steady-state responses

Auditory brainstemresponses(ABRs)andtheirsteady-statecounterpart(subcorticalsteady-state
responses,SSSRs)aregenerallythoughttobeinsensitivetocognitivedemands.However,a
handfulofstudiesreportthatSSSRsaremodulated dependingonthesubject'sfocusofattention,
either towardsorawayfromanauditorystimulus. Here,weexploredwhetherattentionalfocus
affectstheenvelope-followingresponse(EFR),whichisaparticularkindofSSSR,andifso,
whethertheeffectsarespecific towhichsoundelementsinasoundmixtureasubjectisattending
(selectiveauditoryattentionalmodulation),specific toattendedsensoryinput(inter-modal
attentionalmodulation),orinsensitivetoattentional focus.WecomparedthestrengthofEFR-
stimulusphaselockinginhumanlistenersundervarioustasks:listeningtoamonauralstimulus,
selectively attendingtoaparticularearduringdichotic stimuluspresentation,andattendingto
visualstimuliwhileignoringdichoticauditory inputs.Weobservednosystematicchangesinthe
EFR acrossexperimentalmanipulations,eventhoughcorticalEEGrevealedattention-related
modulations ofalphaactivityduringthetask. We concludethatattentionaleffects,ifany,on
humansubcorticalrepresentation ofsoundscannotbeobservedrobustlyusingEFRs.

Subjects--Topical Terms:
Frequency-following response FFR Envelope-following response Attention Auditory processing