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We assessed different aspects of tactile perception in young children (3–6 years) with autism. Autistic and neurotypical children completed vibrotactile tasks assessing reaction time, amplitude discrimination (sequential and simultaneous) and temporal discrimination (temporal order judgment and duration discrimination). Autistic children had elevated and more variable reaction times, suggesting slower perceptual-motor processing speed and/or greater distractibility. Children with autism also showed higher amplitude discrimination and temporal order judgement thresholds compared to neurotypical children. Tactile perceptual metrics did not associate with social or tactile sensitivities measured by parent-reports. Altered tactile behavioral responses appear in early childhood, can be quantified but appear dissociated from sensitivity. This implies these measures are complementary, but not necessarily related, phenomena of atypical tactile perception in autism.

Several theories have been proposed to explain the presentation of intense interests in autism, including theories based on altered executive functioning, imbalanced reward sensitivity, and mitigating anxiety. These theories have yet to be examined in early childhood, yet knowledge of how intense interests emerge could provide insight into how best to manage intensity and support the many benefits of personal interests. Parents of 33 autistic and 42 non-autistic comparison children aged 3–6 years completed questionnaires to assess attention shifting and inhibitory control, responsiveness to rewards, and anxiety symptoms. Each behavior domain was examined for associations with parent-reported interest intensity. In autistic and comparison children, attention shifting was associated with interest intensity, where children with more difficulties showed more intense interests. In autistic children only, inhibitory control of attention also associated with interest intensity, where children with greater difficulties showed more intense interests. Reward and anxiety symptoms did not associate with interest intensity in either group, or across the sample. These findings suggest that, in early childhood, the presentation of intense interests is related to executive functioning regardless of diagnostic group. Helping children develop executive functioning skills may therefore be useful to assist with managing interest intensity in early childhood. Lay abstract Personal interests in autism are a source of joy, pride, and assist with the formation of social relationships. However, highly intense engagement can also interfere with other activities including activities of daily living. Theories have suggested that intense interests relate to executive functioning, reward sensitivity, and anxiety symptoms; but none of these theories have been tested in early childhood. Understanding which behavioral traits relate to intense interests in early childhood could help understand how intense interests may emerge, while also providing clues for how to manage interest intensity and best promote the many benefits of personal interests. We recruited families with autistic and non-autistic children aged 3–6 years. Parents completed questionnaires to assess children’s interest diversity and intensity, executive functioning, reward sensitivity, and anxiety symptoms. We found that for autistic and non-autistic children, greater difficulty shifting attention between activities related to more intense interests. In autistic children only, difficulty with inhibitory control of attention also related to more intense interests. However, reward sensitivity and anxiety symptoms did not relate to interest intensity. Based on these observations, assisting young children with developing executive functioning skills could help with mediating the interference of interests in daily life to ultimately promote the many benefits of personal interests.

Background Unusual behavioral reactions to sensory stimuli are frequently reported in individuals on the autism spectrum (AS). Despite the early emergence of sensory features ( Methods Here, we used electroencephalography (EEG) to investigate tactile cortical processing in young children aged 3–6 years with autism and in neurotypical (NT) children. Scalp EEG was recorded from 33 children with autism, including those with low cognitive and/or verbal abilities, and 45 age- and sex-matched NT children during passive tactile fingertip stimulation. We compared properties of early and later somatosensory-evoked potentials (SEPs) and their adaptation with repetitive stimulation between autistic and NT children and assessed whether these neural measures are linked to “real-world” parent-reported tactile reactivity. Results As expected, we found elevated tactile reactivity in children on the autism spectrum. Our findings indicated no differences in amplitude or latency of early and mid-latency somatosensory-evoked potentials (P50, N80, P100), nor adaptation between autistic and NT children. However, latency of later processing of tactile information (N140) was shorter in young children with autism compared to NT children, suggesting faster processing speed in young autistic children. Further, correlational analyses and exploratory analyses using tactile reactivity as a grouping variable found that enhanced early neural responses were associated with greater tactile reactivity in autism. Limitations The relatively small sample size and the inclusion of a broad range of autistic children (e.g., with low cognitive and/or verbal abilities) may have limited our power to detect subtle group differences and associations. Hence, replications are needed to verify these results. Conclusions Our findings suggest that electrophysiological somatosensory cortex processing measures may be indices of “real-world” tactile reactivity in early childhood autism. Together, these findings advance our understanding of the neurophysiological mechanisms underlying tactile reactivity in early childhood autism and, in the clinical context, may have therapeutic implications.

Background: Unusual responses to sensory stimuli are frequently reported in individuals on the autism spectrum (AS). Despite the early emergence of sensory features (Methods: Here, we used electroencephalography (EEG) to investigate tactile cortical processing in young children aged 3-6 years with autism and in neurotypical (NT) children. Scalp EEG was recorded from 33 children with autism, including those with low cognitive and/or verbal abilities, and 45 age- and sex-matched NT children during passive tactile fingertip stimulation. We compared properties of early and later somatosensory-evoked potentials (SEPs) and their adaptation with repetitive stimulation between autistic and NT children and assessed whether these neural measures are linked to “real-world” parent-reported behavioral tactile sensitivity.Results: As expected, we found elevated behavioral tactile sensitivity in children on the autism spectrum. Our findings indicated no differences in amplitude or latency of early and mid-latency somatosensory-evoked potentials (P50, N80, P100), nor adaptation between autistic and NT children. However, latency of later processing of tactile information (N140) differed between young children with and without autism, suggesting faster processing speed in young autistic children. Further, correlational analyses and exploratory analyses using tactile phenotype as a grouping variable found that enhanced early neural responses were associated with greater behavioral tactile sensitivity in autism. Limitations: The relatively small sample size and the inclusion of a broad range of autistic children (e.g., with low cognitive and/or verbal abilities) may have limited our power to detect subtle group differences and associations. Hence, replications are needed to verify these results.Conclusions: Our findings suggest that electrophysiological somatosensory cortex processing measures may be indices of “real-world” tactile sensitivity in early childhood autism. Together, these findings advance our understanding of the neurophysiological mechanisms underlying tactile sensitivity in early childhood autism and, in the clinical context, may have therapeutic implications.

Tactile perception plays a pivotal role in the early stages of human development; however, little is known about tactile function in young children. A better understanding of how tactile function improves with age from early childhood to adulthood is fundamental in understanding atypical tactile experiences in childhood-onset neurodevelopmental disorders, including autism spectrum disorder. In this study, one hundred and forty-two children and adults aged 3–23 years completed a vibrotactile testing battery consisting of five tasks, which rely on different cortical mechanisms. The battery was designed to be suitable for testing in young children and was used to investigate tactile perception from early childhood to adulthood. Our results show a general pattern of rapid, age-related improvements in tactile perception (lower discrimination threshold = greater sensitivity) across early childhood (ages 3–6 years). However, differences in the rate of change across tasks were observed, with tactile performance reaching adult-like levels earlier on same tasks than others. These findings highlight that early childhood is a period of rapid changes in tactile perception, and that the different underlying cortical, physical and cognitive development processes likely develop at different rates. Further, we are the first to show the feasibility of vibrotactile testing in an early childhood sample, which has important clinical implications for examining developmental disorders with altered tactile function and our results can be used as a reference.

Movie-watching is becoming a popular acquisition method to increase compliance and enable neuroimaging data collection in challenging populations such as children, with potential to facilitate studying the somatosensory system. However, relatively little is known about the possible crossmodal (audiovisual) influence of movies on cortical somatosensory processing. In this study, we examined the impact of dynamic audiovisual movies on concurrent cortical somatosensory processing using electroencephalography (EEG). Forty healthy young adults (18-25 years) received passive tactile fingertip stimulation while watching an "entertaining" movie and a novel "low-demand" movie called 'Inscapes' compared to eyes-open rest. Watching a movie did not modulate properties of early or late somatosensory-evoked potentials (SEPs). Similarly, no crossmodal influence on somatosensory adaptation, denoted by a reduction in SEP amplitude with repetitive tactile stimulation, was found. The prominent oscillatory responses in the alpha and beta frequency bands following tactile stimulation differed as a function of viewing condition, with stronger alpha/beta event-related desynchronization (ERD) during movie-watching compared to rest. These findings highlight that movie-watching is a valid acquisition method during which SEPs can be measured in basic research and clinical studies, but that the attentional demands of movies need to be taken into account when performing oscillatory analyses.

Recovery of skilled movement after stroke is assumed to depend on motor learning. However, the capacity for motor learning and factors that influence motor learning after stroke have received little attention. In this study, we first compared motor skill acquisition and retention between well-recovered stroke patients and age- and performance-matched healthy controls. We then tested whether beta oscillations (15–30 Hz) from sensorimotor cortices contribute to predicting training-related motor performance. Eighteen well-recovered chronic stroke survivors (mean age 64 ± 8 years, range: 50–74 years) and 20 age- and sex-matched healthy controls were trained on a continuous tracking task and subsequently retested after initial training (45–60 min and 24 h later). Scalp electroencephalography was recorded during the performance of a simple motor task before each training and retest session. Stroke patients demonstrated capacity for motor skill learning, but it was diminished compared to age- and performance-matched healthy controls. Furthermore, although the properties of beta oscillations prior to training were comparable between stroke patients and healthy controls, stroke patients did show less change in beta measures with motor learning. Lastly, although beta oscillations did not help to predict motor performance immediately after training, contralateral (ipsilesional) sensorimotor cortex post-movement beta rebound measured after training helped predict future motor performance, 24 h after training. This finding suggests that neurophysiological measures such as beta oscillations can help predict response to motor training in chronic stroke patients and may offer novel targets for therapeutic interventions., Espenhahn et al. report that motor skill learning ability is preserved after stroke, but diminished compared to healthy controls. Movement-related beta dynamics after training helped predict future motor performance, suggesting that beta oscillations may have value as markers of motor system (dys)function after stroke., Graphical Abstract Graphical Abstract

Recovery of skilled movement after stroke is assumed to depend on motor learning. However, the capacity for motor learning and factors that influence motor learning after stroke have received little attention. In this study we firstly compared motor skill acquisition and retention between well-recovered stroke patients and age- and performance-matched healthy controls. We then tested whether beta oscillations (15–30Hz) from sensorimotor cortices contribute to predicting training-related motor performance.Eighteen well-recovered chronic stroke survivors (mean age 64±8 years, range 50–74 years) and twenty age- and sex-matched healthy controls were trained on a continuous tracking task and subsequently retested after initial training (45–60 min and 24 hours later). Scalp EEG was recorded during the performance of a simple motor task before each training and retest session. Stroke patients demonstrated capacity for motor skill learning, but it was diminished compared to age- and performance-matched healthy controls. Further, although the properties of beta oscillations prior to training were comparable between stroke patients and healthy controls, stroke patients did show less change in beta measures with motor learning. Lastly, although beta oscillations did not help to predict motor performance immediately after training, contralateral (ipsilesional) sensorimotor cortex post-movement beta rebound (PMBR) measured after training helped predict future motor performance, 24 hours after training. This finding suggests that neurophysiological measures such as beta oscillations can help predict response to motor training in chronic stroke patients and may offer novel targets for therapeutic interventions.

© 2019 The Authors People vary in their capacity to learn and retain new motor skills. Although the relationship between neuronal oscillations in the beta frequency range (15–30 Hz) and motor behaviour is well established, the electrophysiological mechanisms underlying individual differences in motor learning are incompletely understood. Here, we investigated the degree to which measures of resting and movement-related beta power from sensorimotor cortex account for inter-individual differences in motor learning behaviour in the young and elderly. Twenty young (18–30 years) and twenty elderly (62–77 years) healthy adults were trained on a novel wrist flexion/extension tracking task and subsequently retested at two different time points (45–60 min and 24 h after initial training). Scalp EEG was recorded during a separate simple motor task before each training and retest session. Although short-term motor learning was comparable between young and elderly individuals, there was considerable variability within groups with subsequent analysis aiming to find the predictors of this variability. As expected, performance during the training phase was the best predictor of performance at later time points. However, regression analysis revealed that movement-related beta activity significantly explained additional variance in individual performance levels 45–60 min, but not 24 h after initial training. In the context of disease, these findings suggest that measurements of beta-band activity may offer novel targets for therapeutic interventions designed to promote rehabilitative outcomes.

Although social comparison is a known determinant of overall life satisfaction, it is not clear how it affects moment-to-moment variation in subjective emotional state. Using a novel social decision task combined with computational modelling, we show that a participant's subjective emotional state reflects not only the impact of rewards they themselves receive, but also the rewards received by a social partner. Unequal outcomes, whether advantageous or disadvantageous, reduce average momentary happiness. Furthermore, the relative impacts of advantageous and disadvantageous inequality on momentary happiness at the individual level predict a subject's generosity in a separate dictator game. These findings demonstrate a powerful social influence upon subjective emotional state, where emotional reactivity to inequality is strongly predictive of altruism in an independent task domain., Comparing oneself to others is inherently human but exactly how social comparison affects one's emotional state is unclear. Here the authors demonstrate that unequal social outcomes decrease happiness and these emotional impacts are proportional to individual levels of generosity.

Combining transcranial magnetic stimulation (TMS) and electroencephalography (EEG) constitutes a powerful tool to directly assess human cortical excitability and connectivity. TMS of the primary motor cortex elicits a sequence of TMS-evoked EEG potentials (TEPs). It is thought that inhibitory neurotransmission through GABA-A receptors (GABAAR) modulates early TEPs (

Realistic field calculations in transcranial neurostimulation promise a better insight into the position and extent of the affected brain areas and improve the spatial specificity of stimulation. This is underlined by recent work that demonstrated a strong influence of individual gyral geometry on the strength and distribution of the induced electric field [1]. The field calculations are based on fundamental laws of electrodynamics and rely on conductivity model of individual heads, which are based on segmented structural MR images. For the wider application and the general acceptance of electric field modeling for neurostimulation, two steps seem essential: – a demonstration that the simulated fields correlate with observable effects of neurostimulation (e.g. behavioral or electrophysiological). That is, the simulated fields contribute accurate and relevant information to the experiments; integration electric field modeling into regular TMS experiments in a user-friendly way. Methods and results.– We demonstrate the integration of the Simulation for Non-Invasive Brain Stimulation (SimNIBS, www.simnibs.de) software package with neuronavigation tools for TMS (VISOR from ANT). The coil position and orientation for each TMS pulse is saved by VISOR. These coil positions are automatically converted into the SimNIBS format and used to carry out electric field simulations for each coil position. First results from TMS-motor mapping show how the simulated electric fields can be correlated with the motor evoked potentials of individual muscles. Conclusion.– These results demonstrate that advanced electric field simulations can be applied routinely in experiments involving TMS. In addition, the application to TMS-motor mapping allows validating these simulations in a brain system that is well characterized.

Much of our knowledge on the physiological mechanisms of transcranial magnetic stimulation (TMS) stems from studies which targeted the human motor cortex. However, it is still unclear which part of the motor cortex is predominantly affected by TMS. Considering that the motor cortex consists of functionally and histologically distinct subareas, this also renders the hypotheses on the physiological TMS effects uncertain. We use the finite element method (FEM) and magnetic resonance image-based individual head models to get realistic estimates of the electric field induced by TMS. The field changes in different subparts of the motor cortex are compared with electrophysiological threshold changes of 2 hand muscles when systematically varying the coil orientation in measurements. We demonstrate that TMS stimulates the region around the gyral crown and that the maximal electric field strength in this region is significantly related to the electrophysiological response. Our study is one of the most extensive comparisons between FEM-based field calculations and physiological TMS effects so far, being based on data for 2 hand muscles in 9 subjects. The results help to improve our understanding of the basic mechanisms of TMS. They also pave the way for a systematic exploration of realistic field estimates for dosage control in TMS.