Transcranial magnetic stimulation over human secondary somatosensory cortex disrupts perception of pain intensity.

Pain is a complex sensory experience resulting from the activity of a network of brain regions. However, the functional contribution of individual regions in this network remains poorly understood. We delivered single-pulse transcranial magnetic stimulation (TMS) to the contralateral primary somatosensory cortex (S1), secondary somatosensory cortex (S2) and vertex (control site) 120 msec after selective stimulation of nociceptive afferents using neodymium:yttrium-aluminium-perovskite (Nd:YAP) laser pulses causing painful sensations. Participants were required to judge either the intensity (medium/high) or the spatial location (proximal/distal) of the stimulus in a two-alternative forced choice paradigm. When TMS pulses were delivered over S2, participants' ability to judge pain intensity was disrupted, as compared to S1 and vertex (control) stimulation. Signal-detection analysis demonstrated a loss of sensitivity to stimulation intensity, rather than a shift in perceived pain level or response bias. We did not find any effect of TMS on the ability to localise nociceptive stimuli on the skin. The novel finding that TMS over S2 can disrupt perception of pain intensity suggests a causal role for S2 in encoding of pain intensity

Behavioural and neurobiological foundations of vicarious processing

Empathy can be broadly defined as the ability to vicariously experience and to understand the affect of other people. This thesis will argue that such a capacity for vicarious processing is fundamental for successful social-cognitive ability and behaviour. To this end, four outstanding research questions regarding the behavioural and neural basis of empathy are addressed 1) can empathy be dissected into different components and do these components differentially explain individual differences in social functioning? [Chapter 2] 2) how does empathy relate to trait prosocial behaviour and do additional trait constructs moderate the association between empathy and prosocial behaviour? [Chapter 3] 3) how does the brain represent vicarious information, and does this vary dependent on individual differences in typical and atypical empathy? [Chapters 4-5] 4) what are the behavioural and neural mechanisms that link empathy to prosocial behaviour? [Chapter 6] The findings of this thesis suggest that: 1) specific components of empathy have distinct associations with different kinds of disrupted trait social-cognitive ability 2) specific components of empathy are positively associated with trait prosocial behaviour and individual differences in the capacity to regulate one’s own emotions moderates the strength with which empathy relates to trait prosocial behaviour 3) anterior cingulate cortex function may be critical in the perception of vicarious information, including pain and reward processing; and individual differences in anterior cingulate cortex function during pain and reward processing relates to individual differences in empathy and 4) empathy is important for prosocial decision making and underpins the neural computations that signal outcomes for others that are different from our expectations. Together, these findings contribute to a more complete and coherent understanding of the structure, function and neural basis of empathic/vicarious processing

Probing apathy in children and adolescents with the Apathy Motivation Index–Child version

Apathy is linked to mental health and altered neurocognitive functions such as learning and decision-making in healthy adults. Mental health problems typically begin to emerge during adolescence, yet little is known about how apathy develops due to an absence of quantitative measurements specific to young people. Here, we present and evaluate the Apathy Motivation Index–Child Version (AMI-CV) for children and adolescents. We show across two samples of young people (aged 8 to 17 years, total N = 191) tested in schools in the UK and on a smartphone app, that the AMI-CV is a short, psychometrically sound measure to assess levels of apathy and motivation in young people. Similar to adult versions, the AMI-CV captures three distinct apathy domains: Behavioural Activation, Social Motivation and Emotional Sensitivity. The AMI-CV showed excellent construct validity with an alternative measure of apathy and external validity replicating specific links with related mental health traits shown in adults. Our results provide a short measure of self-reported apathy in young people that enables research into apathy development. The AMI-CV can be used in conjunction with the adult version to investigate the impact of levels of apathy across the lifespan

l-DOPA and oxytocin influence the neurocomputational mechanisms of self-benefitting and prosocial reinforcement learning.

Humans learn through reinforcement, particularly when outcomes are unexpected. Recent research suggests similar mechanisms drive how we learn to benefit other people, that is, how we learn to be prosocial. Yet the neurochemical mechanisms underlying such prosocial computations remain poorly understood. Here, we investigated whether pharmacological manipulation of oxytocin and dopamine influence the neurocomputational mechanisms underlying self-benefitting and prosocial reinforcement learning. Using a double-blind placebo-controlled cross-over design, we administered intranasal oxytocin (24 IU), dopamine precursor l-DOPA (100 mg + 25 mg carbidopa), or placebo over three sessions. Participants performed a probabilistic reinforcement learning task with potential rewards for themselves, another participant, or no one, during functional magnetic resonance imaging. Computational models of reinforcement learning were used to calculate prediction errors (PEs) and learning rates. Participants behavior was best explained by a model with different learning rates for each recipient, but these were unaffected by either drug. On the neural level, however, both drugs blunted PE signaling in the ventral striatum and led to negative signaling of PEs in the anterior mid-cingulate cortex, dorsolateral prefrontal cortex, inferior parietal gyrus, and precentral gyrus, compared to placebo, and regardless of recipient. Oxytocin (versus placebo) administration was additionally associated with opposing tracking of self-benefitting versus prosocial PEs in dorsal anterior cingulate cortex, insula and superior temporal gyrus. These findings suggest that both l-DOPA and oxytocin induce a context-independent shift from positive towards negative tracking of PEs during learning. Moreover, oxytocin may have opposing effects on PE signaling when learning to benefit oneself versus another.NWO452-12-005Stress and Psychopatholog

Peripheral Serotonin 1B Receptor Transcription Predicts the Effect of Acute Tryptophan Depletion on Risky Decision-Making

BACKGROUND: The effects of acute tryptophan depletion on human decision-making suggest that serotonin modulates the processing of rewards and punishments. However, few studies have assessed which of the many types of serotonin receptors are responsible. METHODS: Using a within-subject, double-blind, sham-controlled design in 26 subjects, we examined whether individual differences in serotonin system gene transcription, measured in peripheral blood, predicted the effect of acute tryptophan depletion on decision-making. Participants performed a task in which they chose between successive pairs of fixed, lower-stakes (control) and variable, higher-stakes (experimental) gambles, each involving wins or losses. In 21 participants, mRNA from 9 serotonin system genes was measured in whole blood prior to acute tryptophan depletion: 5-HT1B, 5-HT1F, 5-HT2A, 5-HT2B, 5-HT3A, 5-HT3E, 5-HT7 (serotonin receptors), 5-HTT (the serotonin transporter), and tryptophan hydroxylase 1. RESULTS: Acute tryptophan depletion did not significantly influence participants' sensitivity to probability, wins, or losses, although there was a trend for a lower tendency to choose experimental gambles overall following depletion. Significant positive correlations, which survived correction for multiple comparisons, were detected between baseline 5-HT1B mRNA levels and acute tryptophan depletion-induced increases in both the overall tendency to choose the experimental gamble and sensitivity to wins. No significant relationship was observed with any other peripheral serotonin system markers. Computational analyses of decision-making data provided results consistent with these findings. CONCLUSIONS: These results suggest that the 5-HT1B receptor may modulate the effects of acute tryptophan depletion on risky decision-making. Peripheral levels of serotonin markers may predict response to treatments that act upon the serotonin system, such as selective serotonin reuptake inhibitors

A dual-fMRI investigation of the iterated Ultimatum Game reveals that reciprocal behaviour is associated with neural alignment

Dyadic interactions often involve a dynamic process of mutual reciprocity; to steer a series of exchanges towards a desired outcome, both interactants must adapt their own behaviour according to that of their interaction partner. Understanding the brain processes behind such bidirectional reciprocity is therefore central to social neuroscience, but this requires measurement of both individuals’ brains during realworld exchanges. We achieved this by performing functional magnetic resonance imaging (fMRI) on pairs of male individuals simultaneously while they interacted in a modifed iterated Ultimatum Game (iUG). In this modifcation, both players could express their intent and maximise their own monetary gain by reciprocating their partner’s behaviour – they could promote generosity through cooperation and/or discourage unfair play with retaliation. By developing a novel model of reciprocity adapted from behavioural economics, we then show that each player’s choices can be predicted accurately by estimating expected utility (EU) not only in terms of immediate payof, but also as a reaction to their opponent’s prior behaviour. Finally, for the frst time we reveal that brain signals implicated in social decision making are modulated by these estimates of EU, and become correlated more strongly between interacting players who reciprocate one another

Specific orofacial problems experienced by musicians

Background: Patients who play musical instruments (especially wind and stringed instruments) and vocalists are prone to particular types of orofacial problems. Some problems are caused by playing and some are the result of dental treatment. This paper proposes to give an insight into these problems and practical guidance to general practice dentists. Method: Information in this paper is gathered from studies published in dental, music and occupational health journals, and from discussions with career musicians and music teachers. Results: Orthodontic problems, soft tissue trauma, focal dystonia, denture retention, herpes labialis, dry mouth and temporomandibular joint (TMJ) disorders were identified as orofacial problems of career musicians. Options available for prevention and palliative treatment as well as instrument selection are suggested to overcome these problems. Conclusions: Career musicians express reluctance to attend dentists who are not sensitive to their specific needs. General practitioner dentists who understand how the instruments impact on the orofacial structures and are aware of potential problems faced by musicians are able to offer preventive advice and supportive treatment to these patients, especially those in the early stages of their career

Understanding resilience of female adolescents towards teenage pregnancy: a cross-sectional survey in Dar es Salaam, Tanzania

Abstract Background In Tanzania, teenage pregnancy rates are still high despite the efforts being made to reduce them. Not enough is known about how adolescents experience and cope with sexuality and teenage pregnancy. Over the past few decades, most studies have focused on vulnerability and risk among youth. The concept of ‘reproductive resilience’ is a new way of looking at teenage pregnancy. It shifts the perspective from a deficit-based to a strength-based approach. The study presented here aimed to identify factors that could contribute to strengthening the reproductive resilience of girls in Dar es Salaam, Tanzania. Methods Using a cross-sectional cluster sampling approach, 750 female adolescents aged 15–19 years were interviewed about how they mobilize resources to avoid or deal with teenage pregnancy. The main focus of the study was to examine how social capital (relations with significant others), economic capital (command over economic resources), cultural capital (personal dispositions and habits), and symbolic capital (recognition and prestige) contribute to the development of adolescent competencies for avoiding or dealing with teenage pregnancy and childbirth. Results A cumulative competence scale was developed to assess reproductive resilience. The cumulative score was computed based on 10 competence indicators that refer to the re- and pro-active mobilization of resources. About half of the women who had never been pregnant fell into the category, ‘high competence’ (50.9%), meaning they could get the information and support needed to avoid pregnancies. Among pregnant women and young mothers, most were categorized as ‘high competence’ (70.5%) and stated that they know how to avoid or deal with health problems that might affect them or their babies, and could get the information and support required to do so. Cultural capital, in particular, contributed to the competence of never-pregnant girls [OR = 1.80, 95% CI = 1.06 to 3.07, p = 0.029], pregnant adolescents and young mothers [OR = 3.33, 95% CI = 1.15 to 9.60, p = 0.026]. Conclusions The reproductive resilience framework provides new insights into the reproductive health realities of adolescent girls from a strength-based perspective. While acknowledging that teenage pregnancy has serious negative implications for many female adolescents, the findings presented here highlight the importance of considering girls’ capacities to prevent or deal with teenage pregnancy

Facing others’ misfortune: Personal distress mediates the association between maladaptive emotion regulation and social avoidance

Previous research has linked the use of certain emotion regulation strategies to the vicarious experience of personal distress (PD) and empathic concern (EC). However, it has not been tested yet whether (1) vicarious PD is positively associated with maladaptive emotion regulation strategies, (2) vicarious EC is positively associated with adaptive emotion regulation strategies and whether (3) PD and EC mediate the link between emotion regulation and reports of approach/avoidance in response to a person in distress. To that aim, we assessed people’s reports of PD (i.e., anxious, troubled, and upset) and EC (i.e., concerned, sympathetic, and soft-hearted) in response to a video depicting a person in a threatening situation (n = 78). Afterwards, we assessed participants’ reports of avoidance and approach in regards to the character and their disposition to use maladaptive and adaptive emotion regulation strategies. Results showed that PD as well as EC were positively related to maladaptive strategies and negatively related to adaptive strategies, and that the association between maladaptive regulation strategies (i.e., rumination) and the willingness to avoid the person in distress was mediated by greater reports of PD. This study thus expands previous evidence on the relationship between maladaptive regulation strategies and affective empathy and provides novel insights about the main role that personal distress played in the association between maladaptive strategies and social avoidance