Comparison of Common Amplitude Metrics in Event-Related Potential Analysis

Abstract

Waveform data resulting from time-intensive longitudinal designs require careful treatment. In particular, the statistical properties of summary metrics in this area are crucial. We draw on event-related potential (ERP) studies, a field with a relatively long history of collecting and analyzing such data, to illustrate our points. In particular, three summary measures for a component in the average ERP waveform feature prominently in the literature: the maximum (or peak amplitude), the average (or mean amplitude) and a combination (or adaptive mean). We discuss the methodological divide associated with these summary measures. Through both analytic work and simulation study, we explore the properties (e.g., Type I and Type II errors) of these competing metrics for assessing the amplitude of an ERP component across experimental conditions. The theoretical and simulation-based arguments in this article illustrate how design (e.g., number of trials per condition) and analytic (e.g., window location) choices affect the behavior of these amplitude summary measures in statistical tests and highlight the need for transparency in reporting the analytic steps taken. There is an increased need for analytic tools for waveform data. As new analytic methods are developed to address these time-intensive longitudinal data, careful treatment of the statistical properties of summary metrics used for null hypothesis testing is crucial.     

Backward masking interrupts spatial attention,slows downstream processing,and limits conscious perception

The attentional blink (AB) is a difficulty in correctly processing a target when it follows one or more other targets after a short delay. When no backward mask is presented after the last critical target, there is no or little behavioral AB deficit. The mask plays an important role in limiting conscious access to target information. In this electrophysiological study, we tested the impact of masking on the deployment and engagement of attention by measuring the N2pc and P3 components in an RSVP paradigm. We found that the presence of a mask in an AB paradigm reduced the amplitude of the N2pc, P3a, and P3b components. In addition to reducing encoding in memory, masking also reduced the effectiveness of the deployment and engagement of attention on the last target. We discuss the role of these findings in the context of current masking, consciousness, and AB models.     

Learning to stand tall: Idiopathic scoliosis,behavioral electronics,and technologically-assisted patient participation in treatment,c. 1969–1992

Drawing on the archives of American learning psychologist Neal E. Miller, this article investigates the role of instrumentation in the expansion and diversification of the behavior therapy domain from the late 1960s to the early 1990s. Through the case of Miller's research on the use of biofeedback to treat idiopathic scoliosis, it argues that the post-World War II adoption of electronic technology by behavioral psychologists contributed to extending their subject matter to include physiological processes and somatic conditions. It also enabled a technologically-instrumented move outside the laboratory through the development of portable ambulatory treatment devices. Using the example of the Posture-Training Device that Miller and his collaborators invented for the behavioral treatment of idiopathic scoliosis, this paper considers how electromechanical psychological instrumentation illustrated a larger and ambiguous strategic shift in behavior therapy from an orientation toward external control to one of self-control.     

Lexical and sublexical cortical tuning for print revealed by Steady-State Visual Evoked Potentials (SSVEPs) in early readers

There are multiple levels of processing relevant to reading that vary in their visual, sublexical, and lexical orthographic processing demands. Segregating distinct cortical sources for each of these levels has been challenging in EEG studies of early readers. To address this challenge, we applied recent advances in analyzing high-density EEG using Steady-State Visual Evoked Potentials (SSVEPs) via data-driven Reliable Components Analysis (RCA) in a group of early readers spanning from kindergarten to second grade. Three controlled stimulus contrasts—familiar words versus unfamiliar pseudofonts, familiar words versus pseudowords, and pseudowords versus nonwords—were used to isolate coarse print tuning, lexical processing, and sublexical orthography-related processing, respectively. First, three overlapping yet distinct neural sources—left vOT, dorsal parietal, and primary visual cortex were revealed underlying coarse print tuning. Second, we segregated distinct cortical sources for the other two levels of processing: lexical fine tuning over occipito-temporal/parietal regions; sublexical orthographic fine tuning over left occipital regions. Finally, exploratory group analyses based on children's reading fluency suggested that coarse print tuning emerges early even in children with limited reading knowledge, while sublexical and higher-level lexical processing emerge only in children with sufficient reading knowledge.

Research Highlights

• Cognitive processes underlying coarse print tuning, sublexical, and lexical fine tuning were examined in beginning readers.
• Three overlapping yet distinct neural sources—left ventral occipito-temporal (vOT), left temporo-parietal, and primary visual cortex—were revealed underlying coarse print tuning.
• Responses to sublexical orthographic fine tuning were found over left occipital regions, while responses to higher-level linguistic fine tuning were found over occipito-temporal/parietal regions.
• Exploratory group analyses suggested that coarse print tuning emerges in children with limited reading knowledge, while sublexical and higher-level linguistic fine tuning effects emerge in children with sufficient reading knowledge.

     

The effectiveness of a school mindfulness-based intervention on the neural correlates of inhibitory control in children at risk: A randomized control trial

Interest in the applications of mindfulness practice in education is growing in the scientific community. Recent research has shown that mindfulness practice in schools may be beneficial for executive functions (EFs) which are abilities crucial for healthy development. The study of the effects of mindfulness practices on children's neural correlates of EFs, particularly inhibitory control, may provide relevant information about the impact and mechanisms of mindfulness-based interventions (MBIs) in children. The aim of the present study was to investigate the effects of a MBI in elementary school children on the neural correlates of inhibitory control via a randomized controlled trial. Children from two 4th grade classrooms and two 5th grade classrooms located in a school identified as having low socioeconomic status in Santiago de Chile were randomly assigned to either receive a MBI or serve as active controls and receive a social skills program. Both before and after the interventions, electroencephalographic activity was recorded during a modified version of the Go/Nogo task in a subsample of children in each group. Additionally, teachers completed questionnaires of students’ EFs and students completed self-report measures. Results revealed increases in EFs assessed by questionnaires together with improved P3 amplitude associated with successful response inhibition in children who received the MBI compared to active controls. These results contribute to the understanding of the ways in which mindfulness practices can promote the development of inhibitory control together with EF improvement, factors identified as critical for children's social and emotional development and positive mental health.

Research Highlights

• This study investigated the effects of a mindfulness-based intervention in children from a low socioeconomic status school on neural correlates of EFs.
• Children performed a Go/Nogo task while electroencephalographic activity was recorded and completed questionnaires before and after a MBI or an active control program.
• Improvements in EFs assessed by questionnaires together with an increased Nogo-P3 activity associated with successful inhibition in children who received the MBI were found.
• The results could contribute to understand how mindfulness practice can promote the development of inhibitory control in children from vulnerable populations.

     

Electroencephalographic and autonomic alterations in subjects with frequent nightmares during pre-and post-REM periods

Abnormal arousal processes, sympathetic influences, as well as wake-like alpha activity during sleep were reported as pathophysiological features of Nightmare Disorder. We hypothesized that in Nightmare Disorder, wake-like cortical activity and peripheral measures linked to arousals would be triggered by physiological processes related to the initiation of REM periods. Therefore, we examined electroencephalographic (EEG), motor and autonomous (cardiac) activity in a group of nightmare (NM) and healthy control (CTL) subjects during sleep-state-transitions while controlling for the confounding effects of trait anxiety. Based on the second-nights’ polysomnographic recordings of 19 Nightmare Disordered (NM) and 21 control (CTL) subjects, we examined the absolute power spectra focusing on the alpha range, measures of heart rate variability (HRV) and motor (muscle tone) activity during pre-REM and post-REM periods, separately. According to our results, the NM group exhibited increased alpha power during pre-REM, but not in post-REM, or stable, non-transitory periods. While CTL subjects showed increased HRV during pre-REM periods in contrast to post-REM ones, NM subjects did not exhibit such sleep state-specific differences in HRV, but showed more stable values across the examined sleep stages and less overall variability reflecting generally attenuated parasympathetic activity during sleep-state-transitions and during stable, non-transitory NREM states. These differences were not mediated by waking levels of trait anxiety. Moreover, in both groups, significant differences emerged regarding cortical and motor (muscle tone) activity between pre-REM and post-REM conditions, reflecting the heterogeneity of NREM sleep. Our findings indicate that NM subjects’ sleep is compromised during NREM–REM transitions, but relatively stabilized after REM periods. The coexistence of sleep-like and wake-like cortical activity in NM subjects seems to be triggered by REM/WAKE promoting neural activity. We propose that increased arousal-related phenomena in NREM–REM transitions might reflect altered emotional processing in NM subjects.     

Cortical responses to sport-specific stimuli in a standing stop signal task

Executive functions (EF) and especially inhibition have been shown to play an essential role in team sports. However, the underlying cortical mechanisms of EF in real game situations are barely understood, since previous studies predominantly used tests with simplified stimuli in seated positions. Consequently, the aim of the current study was to explore cortical responses to sport-specific stimuli in a standing stop signal task (SST). Cortical activity was investigated in 17 adult amateur soccer players using mobile electroencephalography (EEG) in a standard- (Std) and a sport-specific (Sp) SST. Whereas mean reaction times were significantly longer in the Sp-SST, stop error-rates demonstrated no significant difference. Further, analysis of event-related spectral perturbation (ERSP) in a frontal cluster also showed no significant differences between Std- and Sp-SST for go and stop conditions. Thus, sport-specific stimuli in a standing SST may exhibit similar inhibitory cortical processes as the standard SST, although requiring longer processing times with regards to the more complex visual stimulation. Future studies are needed to further develop realistic paradigms for evaluating sport-specific cognitive performance.