The auditory transient 40-Hz response is insensitive to changes in stimulus features.
Ten subjects were presented with tone pips occasionally interspersed with deviant tone pips of a higher frequency. The transient 40-Hz response was insensitive to change in qualitative stimulus features. In contrast, stimulus changes elicited a later and slower event-related potential, the mismatch negativity (MMN). As a response to changes in stimulus features implies the existence of a memory system, and because changes in qualitative stimulus aspects do not activate the generator mechanisms underlying the 40-Hz response, the 40-Hz response can be dissociated from memory mechanisms. Furthermore, the analysis of phase-locked (synchronous) and non-phase-locked (asynchronous) responses revealed that the 40-Hz response might be caused by the synchronization of already active oscillators.
Tiitinen
H
H
Department of Psychology, University of Helsinki, Finland.
Sinkkonen
J
J
May
P
P
Näätänen
R
R
D000161:Acoustic Stimulation / Q000379:methods*; D000328:Adult; D001921:Brain / Q000502:physiology*; D004562:Electrocardiography; D005072:Evoked Potentials, Auditory; D005260:Female; D006801:Humans; D008297:Male