This study was supported by The Academy of Finland and the Signe and Ane Gyllenberg Foundation (Helsinki, Finland).
Interstimulus interval and the selective-attention effect on auditory ERPs:
“N1 enhancement” versus processing negativity
Article first published online: 30 JAN 2007
Volume 30, Issue 1, pages 71–81, January 1993
How to Cite
TEDER, W., ALHO, K., REINIKAINEN, K. and NÄÄTÄNEN, R. (1993), Interstimulus interval and the selective-attention effect on auditory ERPs:. Psychophysiology, 30: 71–81. doi: 10.1111/j.1469-8986.1993.tb03206.x
- Issue published online: 30 JAN 2007
- Article first published online: 30 JAN 2007
- (Received March 22, 1990; Accepted November 20, 1991)
- Event-related potentials;
- Selective attention;
- Processing negativity;
The attention effect on the auditory event-related potential (ERP) in dichotic conditions was studied as a function of the interstimulus interval (ISI). Subjects attended to stimuli delivered to a designated ear and responded to infrequent pitch deviants in this input. The mean ISI was either 80, 160, 480, or 800 ms. Negative difference waves (Nds) were computed by subtracting ERPs to unattended standards from ERPs to the same stimuli when attended.
The exogenous Nl, as estimated from unattended standard ERPs, was larger contralaterally to the stimulus and inverted in polarity at mastoids. With decreasing ISIs, Nl diminished in amplitude much faster than did the Nd. In addition, Nl latency remained stable, whereas Nd peaked markedly earlier with shorter ISIs, almost perfectly coinciding with the exogenous Nl. However, this temporal coincidence found in grand averages proved to be illusory in single subjects.
The early Nd showed no contralateral asymmetry at its peak, but asymmetry was apparent during the ascending slope. These lateral asymmetries resembled those of the exogenous Nl but occurred later. The early Nd peak was, at least mainly, caused by an endogenous attention effect, the processing negativity (PN), even with very short ISIs, but an effect on the exogenous Nl could not be excluded.