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"Initial-" and "change-orienting reactions": an analysis based on visual single-trial event-related potentials
J L Kenemans1, M N Verbaten, J W Roelofs
1NIDDR, Department of Pharmacy, University of Utrecht, The Netherlands.
Biological Psychology
|June 1, 1989
Summary
This study investigated brain responses to initial stimuli and infrequent changes. Event-related potentials (ERPs) revealed distinct patterns for the initial-orienting reaction (I-OR) and change-orienting reaction (C-OR).
Area of Science:
- Cognitive Neuroscience
- Psychophysiology
Background:
- Orienting reactions are fundamental responses to stimuli.
- Event-related potentials (ERPs) and skin conductance responses (SCRs) are key measures of these reactions.
Purpose of the Study:
- To differentiate the neural correlates of the initial-orienting reaction (I-OR) and the change-orienting reaction (C-OR).
- To examine the effects of stimulus relevance and interstimulus interval (ISI) on these responses.
Main Methods:
- Recorded single-trial ERPs at multiple scalp sites (Oz, Pz, Cz, Fz) during habituation and deviant stimulus series.
- Manipulated stimulus relevance (task-relevant vs. neutral) and interstimulus interval (2.45s vs. 8.45s).
- Measured SCRs during the longer ISI condition.
Main Results:
- Habituation led to decreased N1, P3, and SCR, but not P2-N2.
- Deviant stimuli enhanced P2-N2, P3, and N1 (initially), and SCR (for task-relevant stimuli).
- Longer ISI delayed P3 habituation but did not affect P2-N2 enhancement by deviance.
Conclusions:
- The initial-orienting reaction (I-OR) is primarily associated with the N1 component of ERPs.
- The change-orienting reaction (C-OR) corresponds to the P2-N2 complex in ERPs.