Peter Deschamps

Intranasal oxytocin increases fathers’ observed responsiveness during play with their children: A double-blind within-subject experiment

Recent correlational studies showed that oxytocin is associated with parenting style in humans as in other mammals. Here the first double-blind, placebo-controlled, within-subject experiment with intranasal oxytocin administration is presented. Subjects were 17 fathers with their toddler, observed in two play sessions of 15 min each with an intervening period of 1 week. In the oxytocin condition fathers were more stimulating of their childs exploration than in the placebo condition, and they tended to show less hostility. Parent training experiments might be combined with intranasal oxytocin administration to test differential and cumulative effects of traditional, interaction-focused versus pharmaceutical treatments.

The effect of noradrenergic attenuation by clonidine on inhibition in the stop signal task.

Understanding the neuropharmacology of inhibition is of importance to fuel optimal treatment for disorders such as Attention Deficit/Hyperactivity Disorder. The aim of the present study was to assess the effect of noradrenergic antagonism by clonidine on behavioral-performance and brain-activity indices of inhibition. A placebo-controlled, double-blind, randomized, crossover design was implemented. Male (N=21) participants performed in a visual stop signal task while EEG was recorded under clonidine in one session and under placebo in another. We expected that 100 μg clonidine would have a negative effect on EEG indices of inhibition, the Stop N2 and Stop P3. Furthermore, we expected that clonidine would negatively affect the behavioral measure of inhibition, the stop signal reaction time (SSRT). Behavioral analyses were performed on data of 17 participants, EEG analyses on a subset (N=13). Performance data suggested that clonidine negatively affected attention (response variability, omissions) without affecting inhibition as indexed by SSRT. Electrophysiological data show that clonidine reduced the Stop P3, but not the Stop N2, indicating a partial negative effect on inhibition. Results show that it is unlikely that the Stop P3 reduction was related to the effect of clonidine on lapses of attention and on peripheral cardiovascular functioning. In conclusion, the current dose of clonidine had a negative effect on attention and a partial effect on inhibitory control. This inhibitory effect was restricted to the dorsal region of the prefrontal cortex (presumably the superior frontal gyrus) as opposed to the ventral region of the prefrontal cortex (right inferior frontal gyrus).

Facial mimicry in 6-7 year old children with disruptive behavior disorder and ADHD.

Background Impairments in facial mimicry are considered a proxy for deficits in affective empathy and have been demonstrated in 10 year old children and in adolescents with disruptive behavior disorder (DBD). However, it is not known whether these impairments are already present at an earlier age. Emotional deficits have also been shown in children with attention-deficit/hyperactivity disorder (ADHD). Aims To examine facial mimicry in younger, 6–7 year old children with DBD and with ADHD. Methods Electromyographic (EMG) activity in response to emotional facial expressions was recorded in 47 children with DBD, 18 children with ADHD and 35 healthy developing children. Results All groups displayed significant facial mimicry to the emotional expressions of other children. No group differences between children with DBD, children with ADHD and healthy developing children were found. In addition, no differences in facial mimicry were found between the clinical group (i.e., all children with a diagnosis) and the typically developing group in an analysis with ADHD symptoms as a covariate, and no differences were found between the clinical children and the typically developing children with DBD symptoms as a covariate. Conclusion Facial mimicry in children with DBD and ADHD throughout the first primary school years was unimpaired, in line with studies on empathy using other paradigms.

The effect of the augmentation of cholinergic neurotransmission by nicotine on EEG indices of visuospatial attention.

The cholinergic system has been implicated in visuospatial attention but the exact role remains unclear. In visuospatial attention, bias refers to neuronal signals that modulate the sensitivity of sensory cortex, while disengagement refers to the decoupling of attention making reorienting possible. In the current study we investigated the effect of facilitating cholinergic neurotransmission by nicotine (Nicorette Freshmint 2mg, polacrilex chewing gum) on behavioral and electrophysiological indices of bias and disengagement. Sixteen non-smoking participants performed in a Visual Spatial Cueing (VSC) task while EEG was recorded. A randomized, single-blind, crossover design was implemented. Based on the scarce literature, it was expected that nicotine would specifically augment disengagement related processing, especially manifest as an increase of the modulation of the Late Positive Deflection (LPD) by validity of cueing. No effect was expected on bias related components (cue-locked: EDAN, LDAP; target-locked: P1 and N1 modulations). Results show weak indications for a reduction of the reaction time validity effect by nicotine, but only for half of the sample in which the validity effect on the pretest was largest. Nicotine reduced the result of bias as indexed by a reduced P1 modulation by validity, especially in subjects with strong peripheral responses to nicotine. Nicotine did not affect ERP manifestations of the directing of bias (EDAN, LDAP) or disengagement (LPD).

The effect of enhancing cholinergic neurotransmission by nicotine on EEG indices of inhibition in the human brain

The role of the cholinergic system in inhibition remains to be elucidated. Nicotine is a potent tool to augment this system, but most studies investigated its effects solely on behavior. Reference to brain activity is important to specifically identify inhibition-related mechanisms. In the current study the objective was to elucidate the role of the cholinergic system in inhibition. 16 healthy non-smokers performed in a stop task while EEG was recorded. A pre- versus post-treatment, within subjects, placebo controlled, single-blind design was used. It was hypothesized that nicotine would decrease stop-signal reaction time (SSRT) and increase the amplitude of inhibition-related event related potentials, the stop N2 and stop P3. Behavioral measures show nicotine shortened SSRT, but only when pretreatment values were not taken into account. On EEG measures, an enhanced stop P3 under nicotine was found, but only in a subsample sensitive to nicotine based on diastolic blood pressure. The results are indicative of enhanced inhibitory activity possibly reflecting enhanced activation in the superior frontal gyrus.

The effect of attenuating noradrenergic neurotransmission by clonidine on brain activity measures of visuospatial attention.

In the current study, we investigated the role of noradrenaline in directing (bias) and disengagement of visuospatial attention.

Proactive aggression in early school-aged children with externalizing behavior problems: A longitudinal study on the influence of empathy in response to distress.

The course of proactive aggressive behavior may be affected by empathy in response to sadness and distress of others. The aim of the current study is to examine empathy in response to sadness and distress and its relation to proactive and reactive aggression in a clinical sample of children with externalizing behavior problems. At baseline (T1) and 12 months later (T2), parents and teachers of 104 six- and seven-year-old children completed the Instrument for Reactive and Proactive Aggression. At T1, parents and teachers also reported empathy in response to sadness and distress on the Griffith Empathy Measure. Findings show that low levels of parent-reported empathy at baseline were specifically associated with high parent-reported proactive aggression but not with reactive aggression. Similarly, low teacher-reported empathy was specifically related to high teacher-reported proactive aggression. Furthermore, high parent-reported but not teacher-reported empathy at baseline was associated with low proactive aggression at 12 months after controlling for proactive aggression at baseline. The conclusions support the notion that in the study of the course of aggression in clinical groups, the distinction between proactive and reactive aggression as well as the study of empathy in response to distress is relevant for a better understanding and might be taken into account in the development of future interventions.