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

The phasic evoked cardiac response (ECR) produced by innocuous stimuli requiring cognitive processing may be described as the sum of two independent response components. An initial heart rate (HR) deceleration (ECR1), and a slightly later HR acceleration (ECR2), have been hypothesised to reflect stimulus registration and cognitive processing load, respectively. This study investigated the effects of processing load in the ECR and the event-related potential, in an attempt to find similarities between measures found important in the autonomic orienting reflex context and ERP literature.

ERPs and the evoked cardiac response to auditory stimuli: Intensity and cognitive load effects.

The evoked cardiac response (ECR) may be described as the sum of two independent response components: an initial HR deceleration (ECR1) and a slightly later acceleration (ECR2) hypothesized to reflect stimulus registration and cognitive processing load, respectively. This study investigated processing load effects in the ECR and the event-related potential (ERP). Stimulus intensity was varied within subjects, and cognitive load was varied between subjects, in a counting/no counting task with a long interstimulus interval.

Coherence in children with Attention-Deficit/Hyperactivity Disorder and excess beta activity in their EEG.

Objective: This study investigated differences in coherence measures between two groups of children with Attention-Deficit/Hyperactivity Disorder (ADHD) - with the typical EEG profile (increased theta and decreased beta activity), and with excess beta activity - and a normal control group.

Methods: Thirty-four children with ADHD were included in each of the typical and excess beta groups, and were age and sex matched with 34 control subjects. EEG was recorded from 21 sites during an eyes-closed resting condition.

Methylphenidate effects in attention deficit/hyperactivity disorder: electrodermal and ERP measures during a continuous performance task.

Rationale: Previous research investigating the effects of stimulants, such as methylphenidate (MPH), on children with attention deficit/hyperactivity disorder (AD/HD) has rarely included autonomic measures of arousal.

Objective: Our aim was to clarify the effects of MPH on central and autonomic measures in AD/HD children during a continuous performance task (CPT) using a naturalistic open-label study.

Method: Thirty-six boys (18 AD/HD and 18 control) participated in a CPT over two trial periods, allowing a more valid estimate of the effects of medication, rather than assuming that retesting per se has no substantial impact.

The effect of methylphenidate on response inhibition and the event-related potential of children with attention deficit/hyperactivity disorder.

Children with Attention Deficit/Hyperactivity Disorder (AD/HD) appear to be deficient in inhibitory processes, as reflected in behavioural and electrophysiological measures. This study examined the effect of methylphenidate (MPH) on response inhibition in children with AD/HD. Event-related potentials (ERPs) and skin conductance level (SCL) were recorded from 18 boys with AD/HD and 18 controls while they performed a cued Go/Nogo task with 70% Go probability.

Effects of methylphenidate on EEG coherence in attention-deficit/hyperactivity disorder.

This study investigated the effects of methylphenidate on intrahemispheric and interhemispheric EEG coherence in children with Attention-Deficit/Hyperactivity Disorder (AD/HD). Twenty boys with AD/HD Combined type and 20 age- and sex-matched control subjects, aged 8 to 13 years, participated in this study. EEG was recorded from 21 sites during an eyes-closed resting condition.

Event-related potentials in the auditory oddball as a function of EEG alpha phase at stimulus onset.

Objective: We aimed to examine the relation between the phase of electroencephalogram (EEG) alpha activity at stimulus onset and event-related potentials (ERPs) in a fixed-inter-stimulus interval auditory 'oddball' task, using a novel conceptualisation of orthogonal phase effects (cortical negativity versus positivity, negative driving versus positive driving, waxing versus waning).

Methods: EEG responses to button-press targets, from 14 subjects presented with 4 blocks of 150 stimuli (50% target probability), were examined. Pre-stimulus alpha activity (8-13 Hz) at Pz was assessed for each trial by digital filtering of the EEG.