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Little is known of how autonomic arousal relates to neural responsiveness during auditory attention. We presented N = 21 5-7-year-old children with an oddball auditory mismatch paradigm, whilst concurrently measuring heart rate fluctuations. Children with higher mean autonomic arousal, as indexed by higher heart rate (HR) and decreased high-frequency (0.15-0.8 Hz) variability in HR, showed smaller amplitude N250 responses to frequently presented (70%), 500 Hz standard tones. Follow-up analyses showed that the modal evoked response was in fact similar, but accompanied by more large and small amplitude responses and greater variability in peak latency in the high HR group, causing lower averaged responses. Similar patterns were also observed when examining heart rate fluctuations within a testing session, in an analysis that controlled for between-participant differences in mean HR. In addition, we observed larger P150/P3a amplitudes in response to small acoustic contrasts (750 Hz tones) in the high HR group. Responses to large acoustic contrasts (bursts of white noise), however, evoked strong early P3a phase in all children and did not differ by high/low HR. Our findings suggest that elevated physiological arousal may be associated with high variability in auditory ERP responses in young children, along with increased responsiveness to small acoustic changes., (Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Research from the animal literature suggests that dynamic, ongoing changes in arousal lead to dynamic changes in an individual's state of anticipatory readiness, influencing how individuals distribute their attention to the environment. However, multiple peripheral indices exist for studying arousal in humans, each showing change on different temporal scales, challenging whether arousal is best characterized as a unitary or a heterogeneous construct. Here, in 53 typical 12-month-olds, we recorded heart rate (HR), head movement patterns, electrodermal activity (EDA), and attention (indexed via look duration) during the presentation of 20 min of mixed animations and TV clips. We also examined triggers for high arousal episodes. Using cross-correlations and auto-correlations, we found that HR and head movement show strong covariance on a sub-minute scale, with changes in head movement consistently preceding changes in HR. EDA showed significant covariance with both, but on much larger time-scales. HR and head movement showed consistent relationships with look duration, but the relationship is temporally specific: relations are observed between head movement, HR and look duration at 30 s time-lag, but not at larger time intervals. No comparable relationships were found for EDA. Changes in head movement and HR occurred before changes in look duration, but not for EDA. Our results suggest that consistent patterns of covariation between heart rate, head movement and EDA can be identified, albeit on different time-scales, and that associations with look duration are present for head movement and heart rate, but not for EDA. Our results suggests that there is a single construct of arousal that can identified across multiple measures, and that phasic changes in arousal precede phasic changes in look duration. © 2016 Wiley Periodicals, Inc. Dev Psychobiol 58: 623-639, 2016., (© 2016 Wiley Periodicals, Inc.)

Tonic and phasic differences in peripheral autonomic nervous system (ANS) indicators strongly predict differences in attention and emotion regulation in developmental populations. However, virtually all previous research has been based on individual ANS measures, which poses a variety of conceptual and methodlogical challenges to comparing results across studies. Here we recorded heart rate, electrodermal activity (EDA), pupil size, head movement velocity and peripheral accelerometry concurrently while a cohort of 37 typical 12-month-old infants completed a mixed assessment battery lasting approximately 20 min per participant. We analysed covariation of these autonomic indices in three ways: first, tonic (baseline) arousal; second, co-variation in spontaneous (phasic) changes during testing; third, phasic co-variation relative to an external stimulus event. We found that heart rate, head velocity and peripheral accelerometry showed strong positive co-variation across all three analyses. EDA showed no co-variation in tonic activity levels but did show phasic positive co-variation with other measures, that appeared limited to sections of high but not low general arousal. Tonic pupil size showed significant positive covariation, but phasic pupil changes were inconsistent. We conclude that: (i) there is high covariation between autonomic indices in infants, but that EDA may only be sensitive at extreme arousal levels, (ii) that tonic pupil size covaries with other indices, but does not show predicted patterns of phasic change and (iii) that motor activity appears to be a good proxy measure of ANS activity. The strongest patterns of covariation were observed using epoch durations of 40s per epoch, although significant covariation between indices was also observed using shorter epochs (1 and 5s)., (Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.)