title: Assessment of nonlinear interactions in event-related potentials elicited by stimuli presented at short interstimulus intervals using single-trial data.
abstract: The recording of brain event-related potentials (ERPs) is a widely used technique to investigate the neural basis of sensory perception and cognitive processing in humans. Due to the low magnitude of ERPs, averaging of several consecutive stimuli is typically employed to enhance the signal to noise ratio (SNR) before subsequent analysis. However, when the temporal interval between two consecutive stimuli is smaller than the latency of the main ERP peaks, i.e., when the stimuli are presented at a fast rate, overlaps between the corresponding ERPs may occur. These overlaps are usually dealt with by assuming that there is a simple additive superposition between the elicited ERPs and consequently performing algebraic waveform subtractions. Here, we test this assumption rigorously by providing a statistical framework that examines the presence of nonlinear additive effects between overlapping ERPs elicited by successive stimuli with short interstimulus intervals (ISIs). The results suggest that there are no nonlinear additive effects due to the time overlap per se but that, for the range of ISIs examined, the second ERP is modulated by the presence of the first stimulus irrespective of whether there is time overlap or not. In other words, two ERPs that overlap in time can still be written as an addition of two ERPs but with the second ERP being different from the first. This difference is also present in the case of nonoverlapping ERPs with short ISIs. The modulation effect elicited on the second ERP by the first stimulus is dependent on the ISI value.
authors: KIOS Research Center for Intelligent Systems and Networks, University of Cyprus, Nicosia, Cyprus;
authors: Charalambos
authors: C
authors: Loizides
authors: KIOS Research Center for Intelligent Systems and Networks, University of Cyprus, Nicosia, Cyprus; Cancer Research United Kingdom Cambridge Institute, University of Cambridge, Cambridge, United Kingdom;
authors: Achilleas
authors: A
authors: Achilleos
authors: Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom; and.
authors: Gian Domenico
authors: GD
authors: Iannetti
authors: KIOS Research Center for Intelligent Systems and Networks, University of Cyprus, Nicosia, Cyprus; Department of Bioengineering, McGill University, Montreal, Canada georgios.mitsis@mcgill.ca.
authors: Georgios D
authors: GD
authors: Mitsis
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001703:Biophysics; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D005583:Fourier Analysis; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D008875:Middle Aged; D017711:Nonlinear Dynamics; D013997:Time Factors; D055815:Young Adult
keywords: EEG; ERP; analysis of variance; mixed effects models