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The "amplifier" in Sokolov's Orienting Reflex (OR) mechanism: An EEG/ERP extension
Robert J Barry1, Genevieve Z Steiner-Lim2, Frances M De Blasio1
1Brain & Behaviour Research Institute and School of Psychology, University of Wollongong, Wollongong, Australia.
Summary
This study investigated the Orienting Reflex (OR), finding that arousal levels (tonic OR) significantly influenced immediate responses (phasic OR). This supports Sokolov
Area of Science:
- Neuroscience
- Psychology
- Cognitive Science
Background:
- Sokolov's Orienting Reflex (OR) theory posits two systems: a neuronal model/comparator and an amplifying system.
- Research has primarily focused on the phasic OR (neuronal model), neglecting the amplifying system (tonic OR).
Purpose of the Study:
- To examine phasic and tonic OR profiles in an auditory habituation/dishabituation paradigm.
- To investigate the modulatory role of tonic OR measures on phasic OR measures.
Main Methods:
- Auditory habituation/dishabituation study using electrodermal (skin conductance response/level) and central (P300 ERP, EEG alpha) measures.
- Analysis of phasic OR (SCR, P300) and tonic OR (SCL, alpha amplitude) over trials.
Main Results:
- Phasic OR measures (SCR, P300) showed rapid habituation and recovery.
- Tonic OR measures (SCL, alpha) exhibited significant changes, with decreasing SCL and increasing alpha.
- Phasic OR measures were significantly modulated by prestimulus tonic OR levels, confirming the tonic-as-amplifier hypothesis.
Conclusions:
- The study provides evidence for the tonic-as-amplifier aspect of Sokolov's OR theory.
- Findings suggest that tonic arousal states modulate phasic responses.
- Recommends expanding OR research to include both phasic and tonic peripheral and central measures.
