Alpha-amylase, cortisol, and pupillary responses to social and non-social dynamic scenes in young children with autism spectrum disorder

The symptoms of Autism Spectrum Disorder (ASD) may manifest from deficits in attention/arousal; previous studies found altered autonomic and attentional responses in ASD. We found a larger tonic pupil size (Anderson & Colombo, 2009) and altered phasic pupillary responses to human faces (Anderson, Colombo, & Shaddy, 2006) in 2-5 year old children with ASD. Children (20 - 72 months of age) with ASD (n = 12), Down syndrome (DS; n = 9), and typical development (TD; n = 11) were presented with a social and a non-social video clip to examine pupil, salivary, and visual scanning measures. The ASD group had (a) a larger tonic pupil size, (b) lower tonic levels of AA, significantly related to tonic pupil size, and (c) increased phasic pupil responses to the social stimulus than controls. These findings provide replication and extension of our previous investigations; underlying pathology and early identification measures in ASD are discussed

Association between changes in heart rate variability during the anticipation of a stressful situation and the stress-induced cortisol response

Vagal activity - reflecting the activation of stress regulatory mechanisms and prefrontal cortex activation - is thought to play an inhibitory role in the regulation of the hypothalamus-pituitary-adrenal axis. However, most studies investigating the association between stress-induced changes in heart rate variability (HRV, an index of cardiac vagal tone) and cortisol have shown a non-significant relationship. It has been proposed that physiological changes observed during anticipation of a stressor allow individuals to make behavioral, cognitive, and physiological adjustments that are necessary to deal with the upcoming actual stressor. In this study, in a large sample of 171 healthy adults (96 men and 75 women; mean age = 29.98, SD = 11.07), we investigated whether the cortisol response to a laboratory-based stress task was related to anticipation-induced or stress task-induced changes in HRV. As expected, regression analyses showed that a larger decrease in HRV during the anticipation of a stress task was related to higher stress task-induced cortisol increase, but not cortisol recovery. In line with prior research, the stress task-induced change in HRV was not significantly related to cortisol increase or recovery. Our results show for the first time that anticipatory HRV (reflecting differences in stress regulation and prefrontal activity before the encounter with the stressor) is important to understand the stress-induced cortisol increase

The Functional DRD3 Ser9Gly Polymorphism (rs6280) Is Pleiotropic, Affecting Reward as Well as Movement

Abnormalities of motivation and behavior in the context of reward are a fundamental component of addiction and mood disorders. Here we test the effect of a functional missense mutation in the dopamine 3 receptor (DRD3) gene (ser9gly, rs6280) on reward-associated dopamine (DA) release in the striatum. Twenty-six healthy controls (HCs) and 10 unmedicated subjects with major depressive disorder (MDD) completed two positron emission tomography (PET) scans with [11C]raclopride using the bolus plus constant infusion method. On one occasion subjects completed a sensorimotor task (control condition) and on another occasion subjects completed a gambling task (reward condition). A linear regression analysis controlling for age, sex, diagnosis, and self-reported anhedonia indicated that during receipt of unpredictable monetary reward the glycine allele was associated with a greater reduction in D2/3 receptor binding (i.e., increased reward-related DA release) in the middle (anterior) caudate (p<0.01) and the ventral striatum (p<0.05). The possible functional effect of the ser9gly polymorphism on DA release is consistent with previous work demonstrating that the glycine allele yields D3 autoreceptors that have a higher affinity for DA and display more robust intracellular signaling. Preclinical evidence indicates that chronic stress and aversive stimulation induce activation of the DA system, raising the possibility that the glycine allele, by virtue of its facilitatory effect on striatal DA release, increases susceptibility to hyperdopaminergic responses that have previously been associated with stress, addiction, and psychosis

Sensory Over-Responsivity and ADHD: Differentiating Using Electrodermal Responses, Cortisol, and Anxiety

Deficits in sensory modulation have been linked clinically with impaired attention, arousal, and impulsivity for years, but a clear understanding of the relationship between sensory modulation disorders and attention deficit hyperactivity disorder (ADHD) has proven elusive. Our preliminary work suggested that patterns of salivary cortisol and electrodermal responsivity to sensation may be linked to different groups of children with ADHD; those with and without sensory over-responsivity (SOR). Additionally, SOR has been linked to anxiety, and anxiety has been linked to ADHD. A clearer understanding of the relationship between anxiety, SOR, and ADHD may support a better understanding of ADHD diagnostic subtypes. We examined neuroendocrine, electrodermal and behavioral characteristics and sought to predict group membership among 6- to 12-year-old children with ADHD and SOR (ADHDs), ADHD and no SOR (ADHDt), and typicals (TYP). Behavioral questionnaires were completed to document SOR and anxiety. Lab testing used a Sensory Challenge Protocol (SCP) with concurrent electrodermal measurement and the collection of cortisol prior to and following the SCP. Results substantiated links between SOR and anxiety, in both TYP and ADHD children. Results suggests that ADHD should be considered in conjunction with anxiety and sensory responsivity; both may be related to bottom-up processing differences, and deficits in prefrontal cortex/hippocampal synaptic gating

Perceived mental effort correlates with changes in tonic arousal during attentional tasks

<p>Abstract</p> <p>Background</p> <p>It has been suggested that perceived mental effort reflects changes in arousal during tasks of attention. Such changes in arousal may be tonic or phasic, and may be mediated by the locus-coeruleus norepinephrine (LC-NE) system. We hypothesized that perceived mental effort during attentional tasks would correlate with tonic changes in cortical arousal, as assessed by relative electroencephalogram (EEG) band power and theta/beta ratio, and not with phasic changes in cortical arousal, assessed by P300 amplitude and latency.</p> <p>Methods</p> <p>Forty-six healthy individuals completed tasks that engage the anterior and posterior attention networks (continuous performance task, go/no-go task, and cued target detection task). During completion of the three attentional tasks a continuous record of tonic and phasic arousal was taken. Cortical measures of arousal included frequency band power, theta/beta ratios over frontal and parietal cortices, and P300 amplitude and latency over parietal cortices. Peripheral measures of arousal included skin conductance responses, heart rate and heart rate variance. Participants reported their perceived mental effort during each of the three attentional tasks.</p> <p>Results</p> <p>First, changes in arousal were seen from rest to completion of the three attentional tasks and between the attentional tasks. Changes seen between the attentional tasks being related to the task design and the attentional network activated. Second, perceived mental effort increased when demands of the task increased and correlated with left parietal beta band power during the three tasks of attention. Third, increased mental effort during the go/no-go task and the cued target detection task was inversely related to theta/beta ratios.</p> <p>Conclusion</p> <p>These results indicate that perceived mental effort reflects tonic rather than phasic changes in arousal during tasks of attention. We suggest that perceived mental effort may reflect in part tonic activity of the LC-NE system in healthy individuals.</p

Periprandial changes of the sympathetic–parasympathetic balance related to perceived satiety in humans

Food intake regulation involves various central and peripheral mechanisms. In this study the relevance of physiological responses reflecting the autonomic nervous system were evaluated in relation to perceived satiety. Subjects were exposed to a lunch-induced hunger-satiety shift, while profiling diverse sensory, physiological, and biochemical characteristics at 15 min intervals. Sensory ratings comprised questionnaires with visual analogues scales about their feeling of satiety, desire to eat, fullness, and hunger. Physiological characteristics included heart rate, heart rate variability, and blood pressure, while biochemical markers such as cortisol levels and α-amylase activity were monitored in saliva. The four sensory ratings correlated with heart rate and salivary α-amylase suggesting a higher sympathetic tone during satiety. Furthermore, heart rate variability was associated with age and waist-to-hip ratio and cortisol levels negatively correlated with body mass index. Finally, neither chewing nor swallowing contributed to a heart rate increase at food consumption, but orosensory stimulation, as tested with modified sham feeding, caused a partial increase of heart rate. In conclusion, after meal ingestion critical physiological alterations reveal a elevated sympathetic tone, which is a potential measure of satiety

El cronotipo y el momento del día como moduladores de procesos cognitivos que dependen de la atención

El cronotipo como rasgo perteneciente al ámbito de las diferencias individuales en conjunción con el momento del día ha demostrado influir en el rendimiento cognitivo de los individuos que son evaluados. En la presente tesis doctoral profundizamos en la modulación circadiana de procesos cognitivos dependientes de la atención para, por un lado, contribuir a la mejora de su caracterización neurocientífica, como también para constatar las diferentes técnicas que podrían contribuir a mejorar su rendimiento cognitivo cuando los individuos están fuera de su momento óptimo de acuerdo con su cronotipo. La serie experimental de 4 experimentos que proponemos está basada, en primer lugar, en la teoría de redes atencionales de Michael Posner. En este caso, nos focalizamos en el estudio de la interacción entre la vigilancia y el control ejecutivo (Estudio 1), así como en los diferentes componentes que conforman esta primera función atencional, es decir, la vigilancia de tipo arousal y la vigilancia de tipo ejecutivo también en interacción con el ciclo menstrual (Estudio 2). Por otro lado, desde la teoría de Schneider y Shiffrin sobre la disociación del procesamiento de la información en modo automático y controlado, profundizamos en el curso temporal de ambos procesos a través del paradigma de priming semántico (Estudio 3), y, de forma novedosa, utilizamos el paradigma del Self-Attentional Network en el Estudio 4 para analizar la potencial modulación circadiana sobre procesos atencionales que demandan sistemas de procesamiento y modos de respuesta automáticos y controlados.Chronotype as a trait within individual differences together with the time of day has proven to influence the cognitive performance of individuals. In the present doctoral thesis, we delve into the circadian modulation of these variables on attentional subfunctions allowing, on the one hand, to better characterize them and, on the other, to investigate several techniques that may optimize performance when outside the optimal time of day with respect to chronotype. The experimental series of 4 studies we propose is based, first of all, on Michael Posner’s theory of attentional networks. In this case, we focus on the study of vigilance in interaction with executive control (Study 1), and on the different components that compose the former (i.e., arousal and executive) also in interaction with the menstrual cycle (Study 2). Secondly, from Schneider and Shiffrin’s proposal on automatic and controlled processing, we approach the time course of both processes based on the semantic-priming paradigm (Study 3), and, in a novel way, we use the Self-Attentional Network paradigm in Study 4 to delve into the potential modulating role of circadian rhythms over processes demanding automatic or controlled strategies of response

Acute stress impairs reward learning in men

Acute stress is ubiquitous in everyday life, but the extent to which acute stress affects how people learn from the outcomes of their choices is still poorly understood. Here, we investigate how acute stress impacts reward and punishment learning in men using a reinforcement-learning task. Sixty-two male participants performed the task whilst under stress and control conditions. We observed that acute stress impaired participants' choice performance towards monetary gains, but not losses. To unravel the mechanism(s) underlying such impairment, we fitted a reinforcement-learning model to participants' trial-by-trial choices. Computational modeling indicated that under acute stress participants learned more slowly from positive prediction errors - when the outcomes were better than expected - consistent with stress-induced dopamine disruptions. Such mechanistic understanding of how acute stress impairs reward learning is particularly important given the pervasiveness of stress in our daily life and the impact that stress can have on our wellbeing and mental health.ortuguese Foundation for Science and Technology (FCT) to A. Seara-Cardoso [PTDC/MHC-PCN/2296/2014, co-financed by FEDER through COMPETE2020 under the PT2020 Partnership Agreement (POCI-01-0145-FEDER-016747)] and to A. Mesquita (IF/00750/2015). J. Carvalheiro was supported by a FCT PhD fellowship (PD/BD/128467/2017). This study was conducted at the Psychology Research Centre (PSI/01662), School of Psychology, University of Minho, supported by FCT and the Portuguese Ministry of Science, Technology and Higher Education (UID/PSI/01662/2019), through national funds (PIDDAC