Trials and intensity effects in single-trial ERP components and autonomic responses in a dishabituation paradigm with very long ISIs

https://doi.org/10.1016/j.ijpsycho.2015.08.002Get rights and content

Highlights

  • OR fractionation was found in autonomic and single-trial PCA-derived ERP responses.

  • Novelty and intensity manipulation grouped measures into three patterns.

  • Respiratory pause and four ERP components match the SCR stimulus–response pattern.

Abstract

The phasic orienting reflex (OR) was investigated using single-trial data collected concurrently from 4 autonomic measures and event-related potentials (ERPs). In an auditory dishabituation paradigm, twelve indifferent tones of two intensities (60 or 80 dB, intensity change on trial 11, counterbalanced between subjects) were presented at very long interstimulus intervals (ISIs). Novelty and intensity based stimulus–response patterns were examined seeking ERP analogues of autonomic measures representing pre-OR and OR processing. Skin conductance response (SCR) represented the phasic OR index. EOG-corrected ERP data for 16 subjects were decomposed by a temporal Principal Components Analysis (PCA). SCR diminished over 10 standard trials, recovered on change trial 11, dishabituated to the re-presentation of the standard tone on trial 12, and showed intensity effects at the change — formal requirements for an OR index. The evoked cardiac response (HR) showed no trial or intensity effects. Respiratory pause (RP) decreased linearly over trials and showed recovery but no dishabituation or intensity effect. Peripheral vasoconstriction (PVC) failed to decrement but exhibited an intensity effect. Ten identifiable ERP components were extracted: Na, P1, N1-1, PN, P2, P3a, P3b, a novelty-sensitive HabP3, an intensity-sensitive IntP3, and the Slow Wave (SW). Pattern 1 showed no trial or intensity effects (HR, P1, PN, P2); Pattern 2 showed no trial effect but an intensity effect (PVC, Na, N1-1, P3a); and Pattern 3 demonstrated habituation and an intensity effect (SCR, RP, P3b, HabP3, IntP3, SW). The observed fractionation of autonomic and central measures is consistent with Preliminary Process Theory (PPT) rather than the notion of a unitary OR.

Introduction

The slightest perceived change in the environment evokes the investigatory-orienting reflex (OR), initiating an orientation toward the source of the change. This reaction diminishes rapidly if the change recurs (Pavlov, 1927), but the OR ‘recovers’ if an aspect of the stimulus is altered in any way (Barry, 1996, O'Gorman et al., 1970). The fundamental attributes of the OR (Sokolov, 1963a) include an enhanced response to stimulus novelty (‘newness’), subsequent response reduction with repetition (habituation), recovery when a characteristic of the stimulus is changed, followed by an increased response to representation of the original stimulus (dishabituation; Barry and James, 1981a, Rankin et al., 2009, Thompson and Spencer, 1966). The OR also displays sensitivity to intensity variation, although the relationship between the OR and intensity is less clear than for novelty. A cluster of references by Sokolov indicates a “direct dependence on the intensity of the stimulus” (Sokolov, 1963b, p. 12); this is clarified by the graphs on pages 63 and 196 in the same publication showing a direct proportionality between the OR magnitude and intensity between 50 and 90 dB. Subsequent OR investigations by other researchers support this relationship, along with the prime importance of novelty (Barry, 1977a, Barry, 1977b, Edwards, 1974, Jackson, 1974, Howland and Riesen, 1940, Uno and Grings, 1965).

Sokolov investigated a variety of physiological measures related to the OR and varied novelty, intensity and significance (including instructions from the experimenter). Changes in electrodermal response, respiratory pause (this descriptive term represents the “arrest” of the respiratory activity to a novel event; Sokolov, 1963b, p. 78, 128, and 266), pupil dilation, cephalic vascular dilation, EEG alpha desynchronisation, and peripheral vasoconstriction characterised the OR (Sokolov, 1963b). Skin galvanic response (now termed the skin conductance response, SCR) is considered to be the benchmark autonomic measure of the OR, consistently exhibiting a stimulus–response pattern characteristic of the OR: response decrement (habituation) (Barry, 1975, Barry, 1977b, Jackson, 1974, Edwards, 1975, MacDonald et al., 2012, O'Gorman et al., 1970, Raskin et al., 1969, Rust, 1977, Sokolov, 1963a, Sokolov, 1963b), response recovery when a stimulus aspect changes (Barry and James, 1981a, Edwards, 1974, Edwards, 1975, MacDonald and Barry, 2014, O'Gorman et al., 1970, Sokolov, 1960, Sokolov, 1963b, Steiner and Barry, 2011, Zimny and Schwabe, 1966), and dishabituation to the re-presentation of the original stimulus (Barry and James, 1981a, MacDonald and Barry, 2014, Steiner and Barry, 2011, Steiner and Barry, 2014). The SCR has also demonstrated sensitivity to intensity variation (Barry, 1977a, Barry and Furedy, 1993, Edwards, 1974, Kimmel, 1960, MacDonald et al., 2012, O'Gorman et al., 1970).

Different time-locked measures from a “unitary system” (Sokolov, 1960, p. 191) were assumed to consistently demonstrate the same directional change when influenced by stimuli having the same characteristics (covariation). This notion of a unitary OR has been challenged for auditory (Barry, 1977a, Barry, 1977b) and visual stimuli (Barry and James, 1981a, Barry and James, 1981b). Barry, 1977a, Barry, 1977b parametrically examined the role of novelty, intensity and significance on measures in habituation paradigms very similar to those used by Sokolov. Heart rate (HR; unavailable to Sokolov), EEG alpha desynchronisation, cephalic vasodilation (AC- rather than DC-coupled), respiratory pause (RP), peripheral vasoconstriction (PVC), and SCR were dependent measures. No overall covariation in the phasic responses was found when novelty, intensity, and significance were manipulated; rather, different stimulus–response patterns were reported, indicating response fractionation (i.e., different measures showed different relations with the stimulus parameters). When a stimulus was repeated, diminution of responses was observed for EEG alpha desynchronisation, RP, and SCR. Both SCR and PVC were enhanced by intensity; also, SCR was enhanced with stimulus significance. Heart rate deceleration reflected the mandatory, transient response at stimulus onset, while HR acceleration was an additional aspect attributed to the significance of the stimulus. Only SCR fulfilled all requirements of a phasic OR index: response reduction over trials, and sensitivity to stimulus intensity and significance. The separate measures displayed differential responding to the OR determinants, suggesting they are associated with OR pre-processing rather than being OR components. These findings repudiate the notion of a unitary OR, but unfortunately, even with the available evidence the conception of the unitary OR can still be found.

Subsequent studies substantiated the stimulus–response patterning of these measures reported earlier (Barry and James, 1981a, Barry and James, 1981b, Barry, 1982). Preliminary Process Theory (PPT) was formulated to encompass the fractionating measures (Barry, 1977b, Barry, 1979, Barry, 1996, Barry, 2006, Barry, 2009). Preliminary Process Theory describes aspects of pre-processing and processing of stimulus parameters related to the OR. Stimulus occurrence per se activates initial stimulus registration, marked by HR deceleration and cephalic vasodilation. Respiratory pause and EEG alpha desynchronisation index the ensuing novelty processing. Processing of the intensity of the stimulus, occurring in parallel to novelty processing, is indexed by peripheral vasoconstriction (PVC). The resultant interaction evokes the phasic OR, indexed by SCR. Fig. 1 depicts the sequential and parallel processing in Preliminary Process Theory. The dashed boxes represent the measures innervated by the processing units.

PPT was initially based on autonomic measures and EEG changes. While the separate processing stages are consistently indexed by these measures, the theory's modern relevance depends on its capacity to align ERP components to those established measures (Barry, 1996). OR studies typically employ habituation or dishabituation paradigms to examine novelty. The dishabituation paradigm involves response decrement, response recovery to stimulus change (often misinterpreted as dishabituation), and dishabituation. Notably, in these paradigms, simple tones in the moderate range of intensity and rise/fall times ~ 10 ms are utilised, ensuring an OR rather than the defence or startle reflex. All central measures use linked ears or mastoids as reference unless otherwise stated.

The topography of the N1 typifies the auditory evoked response (AER). Vaughan and Ritter (1970) proposed that “all AERs are maximum at or near the vertex” (p. 362), using tip of the nose as reference. Rushby and Barry (2009) investigated ERP responses to twelve 80 dB tones at very long ISIs in an auditory habituation paradigm, with SCR concurrently measured. The N1 emerged in the baseline-to-peak data and as a temporal PCA component; both exhibited a vertex dominance and no trial effects, consistent with reports in other long ISI habituation studies (Barry et al., 2011, Barry et al., 2013). The N1 has shown sensitivity to intensity manipulations in a variety of paradigms – e.g., it has been applied in the study of loudness dependence of auditory evoked potentials (LDAEP) in relation to serotonin levels; Nathan et al. (2006) – with louder stimuli evoking larger responses (MacDonald et al., 2012, Näätänen and Picton, 1987, Squires et al., 1975, White and Yee, 2006). The N1 (specifically the N1-1 subcomponent, see Barry et al., 2011) and phasic HR deceleration have been associated with stimulus detection, both representing the early PPT stage of transient processing (Lawrence and Barry, 2009, MacDonald et al., 2012). MacDonald and Barry (2014) manipulated novelty in a dishabituation paradigm using 80 dB tones. Two N1 subcomponents were identified from temporal PCA and labelled N1-1 (prominent at the vertex) and N1-3 (parieto-central topography and earlier latency), following Näätänen and Picton (1987). The N1-3 failed to show decrement with repeated stimulation while the N1-1 decremented marginally; both subcomponents were suggested as possible candidates for transient detection.

Similarity between the antecedent conditions of the OR and LPC (Late Positive Complex, also known as the P300) has long been recognised (Donchin et al., 1984). The LPC has been portrayed as a complex marking memory updating of the stimulus context (Donchin, 1981, Donchin and Coles, 1988), sensitivity to stimulus uncertainty (Sutton et al., 1965), degree of expectation (Donchin and Coles, 1988, Verleger, 1988), relevance (Donchin, 1981, Johnson, 1984), and stimulus parameters (Papanicolaou et al., 1985 — left ear reference; Polich et al., 1996). Subcomponents of the LPC were identified in two seminal oddball investigations according to their sensitivity to experimental variables. Squires et al. (1975) identified the P3a linked to intensity variation, while Courchesne et al. (1975) found what became known as the Novelty P3 associated with complex, unrecognisable stimuli; both subcomponents displayed a frontal topography. Subsequently, Principal Components Analysis has decomposed the LPC into at least four distinct subcomponents in habituation paradigms, in increasing latency order: P3a, P3b, Novelty P3, and the Slow Wave (SW), each differing in topography, eliciting conditions, and sensitivity to task demands (Barry et al., 2011, Barry et al., 2013, MacDonald and Barry, 2014, Roth et al., 1982, Sutton and Runchkin, 1984). The P3a has displayed trial decrement at short ISIs (Rushby et al., 2005) but no decrement at very long ISIs (Barry et al., 2013, MacDonald and Barry, 2014, Rushby and Barry, 2009). An unpredictable change in intensity (Barry et al., 2013, Rushby et al., 2005, Squires et al., 1975) has been reported to elicit the P3a. However, Simons et al. (2001) replicated the oddball studies of Squires et al. (1975) and Courchesne et al. (1975) and concluded that the distinction between the Novelty P3 and P3a was not supported empirically. This has become the dominant view in the literature. Despite this, a component identified as the Novelty P3 in habituation studies has consistently decremented to re-presented stimuli (Barry and Rushby, 2006, MacDonald and Barry, 2014, Rushby et al., 2005, Rushby and Barry, 2009) and shown a sensitivity to stimulus recognition and predictability independent of complexity (Courchesne et al., 1975); and no intensity sensitivity (contrasting with the P3a). While the P3a consistently exhibits a central focus (Barry et al., 2013, MacDonald and Barry, 2014), often with a frontal enhancement (Rushby et al., 2005, Rushby and Barry, 2009), the Novelty P3 has been reported with a parietal (Rushby et al., 2005), fronto-central (MacDonald and Barry, 2014), or non-specific (Rushby and Barry, 2009) dominance. Consequently P3a and Novelty P3 may be considered separate PCA-derived ERP entities related to different aspects of the experimental context in OR research. However, in light of Simons et al. (2001), we now label this component from habituation paradigms as HabP3, and recognise that it may not be identical to Courchesne's Novelty P3.

In recent years our laboratory has focused on central measures of the orienting reflex that have been recorded concurrently with autonomic measures. PCA was employed to decompose the subcomponents of the LPC. The SCR has served as the OR ‘yardstick’ in traditional habituation or dishabituation paradigms. Typically the ISIs have been very long and the tones of moderate intensity. MacDonald and Barry (2014) investigated trial effects in autonomic and central measures by presenting 10 identical tones of one frequency (either 1000 Hz or 1500 Hz) to 16 subjects, the change trial consisted of the other frequency, and the original stimulus was re-presented on the 12th trial; all tones were 80 dB with moderate rise/fall times. SCR served as the OR benchmark. Single-trial ERPs, heart rate, and respiratory pause data were concurrently collected and temporal PCA was conducted using EOG-corrected ERP data. The autonomic measures showed the stimulus–response pattern found consistently in other recent studies (Barry et al., 2011, Barry et al., 2013, MacDonald et al., 2012). Nine ERP components/subcomponents emerged from the PCA; interestingly P3a and HabP3 were separable according to novelty manipulation for these data. The P1, N1 subcomponents, PN, P2, and P3a failed to decrement over trials, matching HR deceleration; these measures were considered possible candidates for transient detection and/or intensity processing. The P3b and SW exhibited decrement but no recovery. The HabP3 decremented and showed an increased response on the change trial, matching respiratory pause, and hence was associated with novelty processing. Only the SCR demonstrated the properties of the OR.

Nieuwenhuis et al. (2011) asserts that a difference between two experimental effects (e.g., response decrement in one dependent variable and not another) requires testing the response difference between the measures rather than relying on a qualitative descriptive comparison of the separate significance levels. The statistical difference of these effects is indicated by a significant interaction. In accordance with this rationale, and consistent with MacDonald and Barry (2014), trial and intensity effects in the various measures here will be statistically tested against SCR, the OR index.

This study addresses and extends upon the recommendations of Barry et al. (2013) by manipulating novelty within-subjects, and intensity between-subjects, in a dishabituation rather than habituation paradigm. Some autonomic and central associations have already been proposed. The LPC as an OR marker has received substantial support (Donchin et al., 1984, Rushby et al., 2005, Ritter et al., 1968, Steiner and Barry, 2011), however no ERP component/subcomponent adequately meets the requirements of the OR when novelty, intensity, and significance have been varied. Transient detection appears closely associated with the N1 and HR deceleration, while intensity-insensitive HabP3 and RP demonstrate trial effects, aligning with novelty processing. The P3b and SW may be related to the voluntary OR but no autonomic analogues are obvious.

The present study explores linkages between autonomic and central measures incorporating an intensity change. The auditory stimuli are simple tones of moderate intensity known to generate the OR. Temporal PCA-derived ERP components from single-trial data will be examined with respect to the stimulus–response patterns of SCR, HR, RP, and PVC. We intend to examine the degree of sensitivity of SCR, HR, RP, PVC, and the decomposed ERP components/subcomponents to novelty and intensity variation, thus clarifying the relationships between the various central and autonomic measures in preliminary processing prior to OR generation, and the OR itself. The response decrement of the SCR to variations in novelty for stimuli of moderate intensity has been well established (Barry, 1975, Barry et al., 2011, Blakeslee, 1979, Jackson, 1974, MacDonald et al., 2012, Sokolov, 1963a, Sokolov, 1963b, Steiner and Barry, 2011, Steiner and Barry, 2014). Within-subjects responses are preferred for detecting differences between conditions due to less intrinsic error variance compared to between-subjects responses. Consequentially, our primary focus for detecting an intensity effect is an examination of the response difference between the pre-change trial (trial 10) and the intensity change trial (trial 11). The SCR should demonstrate the consistent OR response pattern: response decrement over repeated standard trials, enhanced response at the change stimulus (more so for the increase in intensity), and an increase to re-presentation of the standard stimulus. The phasic HR deceleration should show no systematic variation over trials or intensity. A strong respiratory pause is anticipated for the first stimulus and the response should decrement with trials (Barry et al., 2013, MacDonald et al., 2012, MacDonald and Barry, 2014), demonstrate an intensity-independent recovery at the change stimulus (Barry and James, 1981a), along with no increased response for the dishabituation trial (Barry and James, 1981a, MacDonald and Barry, 2014). Peripheral vasoconstriction has shown resistance to novelty reduction but a sensitivity to intensity variation (Barry and James, 1981a, Barry and James, 1981b, Barry et al., 2013); PVC should not decrement over trials but reflect changes in intensity.

The temporal PCA will use an ample latency range to encompass ERPs reflecting aspects of the involuntary OR. The P1 has been linked to stimulus onset and preattentive arousal and should be evoked by the first stimulus with no diminution over trials (Gillette et al., 1997 — Fz reference; MacDonald and Barry, 2014, Pratt et al., 2008), however some sensitivity to intensity change may be observed (White and Yee, 2006). The N1, sensitive to stimulus onsets/offsets (Näätänen, 1988, Näätänen and Picton, 1987), should not decrement over trials (Rushby and Barry, 2009, Barry et al., 2011, Barry et al., 2013), and increased intensity may yield greater responses (Näätänen and Picton, 1987, Polich et al., 1996). The novel aspects of the first stimulus should elicit the PN from reflexive attention switching (Barry et al., 2011, MacDonald and Barry, 2014), and that may decrement over trials (Barry et al., 2011). Some PN enhancement may be observed for the low-intensity tone (Näätänen, 1982). The P2 is not expected to show trial effects at these long ISIs (Crowley and Colrain, 2004, MacDonald and Barry, 2014, Rushby and Barry, 2009) but should display an increased response for the 80  dB tone (Crowley and Colrain, 2004, Orlebeke et al., 1989, Roth et al., 1982). The P3a, associated with salience (Goldstein et al., 2002 — Cz reference), involuntary OR (Barry and Rushby, 2006), and attention switching (Dien et al., 2004, Pritchard, 1981) should be unresponsive to stimulus novelty at very long ISIs (Barry et al., 2011, MacDonald and Barry, 2014, Rushby and Barry, 2009), but some sensitivity to changed intensity is expected (Rushby et al., 2005, Squires et al., 1975). The posterior P3b should show response reduction over trials but no overall recovery (Barry et al., 2011, MacDonald and Barry, 2014, Rushby et al., 2005), however the P3b has sometimes shown resistance to decrement (Barry et al., 2013, Rushby and Barry, 2009). An intensity-dependent recovery is expected (Rushby et al., 2005). The HabP3 subcomponent is particularly sensitive to the first instance of a simple stimulus — the ‘newness’ per se (Barry et al., 2011, Rushby and Barry, 2009). The HabP3 should decrement with trials (Barry et al., 2011, MacDonald and Barry, 2014, Rushby et al., 2005, Rushby and Barry, 2009; but not Barry et al., 2013), show recovery independent of intensity (MacDonald and Barry, 2014, Rushby et al., 2005), and possibly dishabituation (MacDonald and Barry, 2014, Rushby et al., 2005). The SW has been associated with the OR (Loveless and Sandford, 1974), so consequently should demonstrate trial effects (MacDonald and Barry, 2014, Rushby et al., 2005, Zimmer and Demmel, 2000; but not Barry et al., 2011, Barry et al., 2013), but no response recovery is expected at these very long ISIs (MacDonald and Barry, 2014), nor intensity effects (Roth et al., 1982, Roth et al., 1984, Rushby et al., 2005).

The present study consolidates and logically extends the investigation of novelty in the OR context by MacDonald and Barry (2014) and Barry et al. (2013) where novelty and intensity were manipulated in a habituation paradigm; as well as addressing the paucity of studies employing ‘genuine’ dishabituation paradigms. This rarely used auditory dishabituation paradigm incorporates the systematic variation of both novelty and intensity with autonomic (including the uncommonly examined RP and PVC) and central data collected concurrently. This unique opportunity permits the possible matching of autonomic and PCA-derived ERPs from the perspective of PPT.

Section snippets

Participants

Sixteen university students participated in an experimental session as one means of fulfilling a course requirement (age 18–25, mean 19.7 years; all female). The procedure was explained and written consent was obtained in accordance with a protocol approved by the joint South East Sydney and Illawarra Area Health Service/University of Wollongong Human Research Ethics Committee, in line with the Declaration of Helsinki (WMO, 1996). Participants were required to complete a demographic and

SCR

The mean SCR waveform displayed onset latency of approx. 1.8 s and peak latency of approx. 3.5 s. Trial decrement was apparent as a linear trend (F = 30.57, p < .001, ηp2 = .686), evident in Fig. 2. The SCR showed both recovery to the change stimulus (11 > 10: F = 9.18, p = .009, ηp2 = .396) and dishabituation (12 > 10: F = 5.77, p = .031, ηp2 = .292). An intensity effect was indicated by the intensity × trial interaction (Intensity × Trial (11 vs. 10): F = 9.03, p = .009, ηp2 = .392). See Table 1.

HR

Fig. 3A shows a clear phasic

Discussion

This dishabituation paradigm employing moderate intensities and very long ISIs was well suited to examine autonomic measures traditionally related to the OR. Novelty and intensity were systematically varied. Few investigations have used the dishabituation paradigm to examine both novelty and intensity from the OR perspective. Central and autonomic single-trial responses were obtained concurrently to permit collection of data from possible rapidly decrementing phasic responses (Roth, 1973 — left

Conclusion

Four autonomic measures and 10 temporal PCA-derived ERP components/subcomponents were examined in an auditory dishabituation paradigm at long ISIs with novelty and intensity varied. The three stimulus–response patterns that emerged were based on the defining aspects of habituation and intensity using SCR as the OR ‘yardstick’. Quantitative comparisons between the measures and SCR, along with correlation considerations, placed autonomic and ERP measures into three patterns. Each of the

References (90)

  • C. Borgmann et al.

    Human auditory middle latency responses: influence of stimulus type and intensity

    Hear. Res.

    (2001)
  • R.J. Croft et al.

    Removal of ocular artifact from the EEG: a review

    Clin. Neurophysiol.

    (2000)
  • K.E. Crowley et al.

    A review of the evidence for P2 being an independent component process: age, sleep and modality

    Clin. Neurophysiol.

    (2004)
  • J. Dien

    The ERP PCA Toolkit: an open source program for advanced statistical analysis of event-related potential data

    J. Neurosci. Methods

    (2010)
  • G.M. Gillette et al.

    combat veterans with posttraumatic stress disorder exhibit decreased habituation of the P1 midlatency audtiory evoked potential

    Life Sci.

    (1997)
  • C.A. Lawrence et al.

    Cognitive processing effects on auditory event-related potentials and the evoked cardiac response

    Int. J. Psychophysiol.

    (2010)
  • N.E. Loveless et al.

    Slow potential correlates of preparatory set

    Biol. Psychol.

    (1974)
  • B. MacDonald et al.

    Trial effects in single-trial ERP components and autonomic responses at very long ISIs

    Int. J. Psychophysiol.

    (2014)
  • B. MacDonald et al.

    Single-trial event-related potentials and autonomic measures of the orienting reflex

    Int. J. Psychophysiol.

    (2012)
  • R. Näätänen

    Implications of ERP data for psychological theories of attention

    Biol. Psychol.

    (1988)
  • I.F. Neves et al.

    Middle latency response study of auditory evoked potentials amplitude and latencies audiologically normal individuals

    Braz. J. Otorhinolaryngol.

    (2007)
  • J.F. Orlebeke et al.

    Disinhibition and the processing of auditory stimulus intensity: an ERP-study

    Personal. Individ. Differ.

    (1989)
  • J. Polich et al.

    P300, stimulus intensity, modality, and probability

    Int. J. Psychophysiol.

    (1996)
  • H. Pratt et al.

    The auditory P50 component to onset and offset of sound

    Clin. Neurophysiol.

    (2008)
  • C.N. Rankin et al.

    Habituation revisited: an updated and revised description of the behavioral characteristics of habituation

    Neurobiol. Learn. Mem.

    (2009)
  • W. Ritter et al.

    Orienting and habituation to auditory stimuli: a study of short term changes in average evoked responses

    Electroencephalogr. Clin. Neurophysiol.

    (1968)
  • W.T. Roth et al.

    Auditory stimulus intensity effects on components of the late positive complex

    Electroencephalogr. Clin. Neurophysiol.

    (1982)
  • J.A. Rushby et al.

    Single-trial event-related potentials to significant stimuli

    Int. J. Psychophysiol.

    (2009)
  • J.A. Rushby et al.

    Separation of the components of the late positive complex in an ERP dishabituation paradigm

    Clin. Neurophysiol.

    (2005)
  • R.F. Simons et al.

    On the relationship of the P3a and the Novelty-P3

    Biol. Psychol.

    (2001)
  • R.R. Sonnadara et al.

    Occasional changes in sound location enhance middle latency evoked responses

    Brain Res.

    (2006)
  • N. Squires et al.

    Two varieties of long-latency positive waves evoked by unpredictable auditory stimuli in man

    Electroencephalogr. Clin. Neurophysiol.

    (1975)
  • H.G. Vaughan et al.

    The sources of auditory evoked responses recorded from the human scalp

    Electroencephalogr. Clin. Neurophysiol.

    (1970)
  • H. Zimmer et al.

    Habituation and laterality of orienting process as reflected by slow negative waves

    Biol. Psychol.

    (2000)
  • H. Althen et al.

    Fast detection of unexpected sound intensity decrements as revealed by human evoked potentials

    PLoS One

    (2011)
  • R.J. Barry

    Low-intensity auditory stimulation and the GSR orienting response

    Physiol. Psychol.

    (1975)
  • R.J. Barry

    Failure to find evidence of the unitary OR concept with indifferent low-intensity auditory stimuli

    Physiol. Psychol.

    (1977)
  • R.J. Barry

    The effect of “significance” upon indices of Sokolov's orienting response: a new conceptualisation to replace the OR

    Physiol. Psychol.

    (1977)
  • R.J. Barry

    Novelty and significance effects in the fractionation of phasic OR measures: a synthesis with traditional OR theory

    Psychophysiology

    (1982)
  • R.J. Barry

    Scoring criteria for response latency and habituation in electrodermal research: a study in the context of the orienting response

    Psychophysiology

    (1990)
  • R.J. Barry

    Preliminary process theory: towards an integrated account of the psychophysiology of cognitive processes

    Acta Neurobiol. Exp. (Wars)

    (1996)
  • R.J. Barry et al.

    Fractionation of respiratory and vascular responses with simple visual stimulation

    Physiol. Psychol.

    (1981)
  • R.J. Barry et al.

    An orienting reflex perspective on anteriorisation of the P3 of the event-related potential

    Exp. Brain Res.

    (2006)
  • P. Blakeslee

    Attention and vigilance: performance and skin conductance response changes

    Psychophysiology

    (1979)
  • E. Courchesne et al.

    Stimulus novelty, task relevance and the visual evoked potential in man

    Electroencephalogr. Clin. Neurophysiol.

    (1975)
  • Cited by (12)

    • Single-trial-based temporal principal component analysis on extracting event-related potentials of interest for an individual subject

      2023, Journal of Neuroscience Methods
      Citation Excerpt :

      Another problem is that, because single-trial EEG are first averaged for each condition before PCA performance, the potential variability of ERP of interest in single-trial EEG among participants may be averaged out during such an averaging procedure. To study the potential variability of ERP components that may be averaged out during averaging procedure, some researchers have performed PCA on the single-trial EEG data for all conditions for all participants to isolate ERP components (Rushby and Barry, 2009; MacDonald and Barry, 2017; MacDonald et al., 2015; Rushby et al., 2005). We name this procedure as single-trial-based group PCA (SGPCA).

    • Stimulus intensity effects and sequential processing in the passive auditory ERP

      2022, International Journal of Psychophysiology
      Citation Excerpt :

      One aim of our group has been to extend this focus to clarify the sequence of stable components apparent within the first 600 ms following presentation of brief innocuous auditory stimuli. This temporal range encompasses the effects of determinants such as intensity for Late Positive Complex (LPC) subcomponents in these habituation-type paradigms at lengthy ISIs (MacDonald et al., 2015). To this end Barry and De Blasio (2013) proposed a processing schema for the equiprobable Go/NoGo task, a paradigm in which one stimulus requires a button-press response, while the equally-probable other does not.

    • Integration of three investigations of Novelty, Intensity, and Significance in dishabituation paradigms: A study of the phasic Orienting Reflex

      2020, International Journal of Psychophysiology
      Citation Excerpt :

      The Interaction test provides a strategy to ascertain if the difference in an effect between the measure and SCR was significant, rather than relying on qualitatively comparing the separate significant levels for each measure. In MacDonald and Barry (2014), MacDonald et al. (2015), and MacDonald and Barry (2017), temporal PCAs have yielded factors that represent specific components identifiable by topography, polarity, latency, and variation with conditions. The labelling of some components is associated with the particular study and/or what was varied, e.g., IntP3 (sensitivity to intensity in the P3 time range).

    • Improving the rigor of psychophysiology research

      2017, International Journal of Psychophysiology
    View all citing articles on Scopus
    View full text