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The curious transference of sensations in the ‘mismatched-palm’ rubber hand illusion
We describe a disconcerting illusion. The participant looks at the palm of a left rubber hand being touched while receiving synchronous touch on the back of their own hidden right hand. Despite postural incongruence, mismatching handedness and touch being at a different location on the viewed and hidden hands, participants experience the illusion of ownership of the rubber hand and the illusion of feeling touch on the rubber hand. The robustness of the rubber hand illusion to seemingly profound incongruencies is explained with reference to Riemer et al.’s four basic principles for successful embodiment.
Microstructural Properties of the Cerebellar Peduncles in Children With Developmental Language Disorder.
Children with developmental language disorder (DLD) struggle to learn their native language for no apparent reason. While research on the neurobiological underpinnings of the disorder has focused on the role of corticostriatal systems, little is known about the role of the cerebellum in DLD. Corticocerebellar circuits might be involved in the disorder as they contribute to complex sensorimotor skill learning, including the acquisition of spoken language. Here, we used diffusion-weighted imaging data from 77 typically developing and 54 children with DLD and performed probabilistic tractography to identify the cerebellum's white matter tracts: the inferior, middle, and superior cerebellar peduncles. Children with DLD showed lower fractional anisotropy (FA) in the inferior cerebellar peduncles (ICP), fiber tracts that carry motor and sensory input via the inferior olive to the cerebellum. Lower FA in DLD was driven by lower axial diffusivity. Probing this further with more sophisticated modeling of diffusion data, we found higher orientation dispersion but no difference in neurite density in the ICP of children with DLD. Reduced FA is therefore unlikely to be reflecting microstructural differences in myelination, rather the organization of axons in these pathways is disrupted. ICP microstructure was not associated with language or motor coordination performance in our sample. We also found no differences in the middle and superior peduncles, the main pathways connecting the cerebellum with the cortex. To conclude, it is not corticocerebellar but atypical olivocerebellar white matter connections that characterize DLD and suggest the involvement of the olivocerebellar system in speech and language acquisition and development.
The effectiveness of positive psychology-based interventions in prisons on well-being: a systematic review and meta-analysis
Positive psychology-based interventions (PPIs) have shown promising evidence for improving psychological well-being in a variety of contexts and are consistent with calls for strengths-based interventions in correctional settings. While these interventions have been tested in prison settings, no study has empircally assessed effectiveness of PPIs for improving psychological well-being in prisons. In this study, we conducted a systematic review and meta-analysis on the effects of PPIs on psychological well-being in prisons. 9 studies (4 RCTs) were included, representing 662 participants. We found large, significant effects on psychological well-being in comparison with control arms (Hedge’s g = 0.76). Additionally, we found large, significant within-group effects (Hedge’s g = 0.66) on psychological well-being. The overall quality of included studies was poor, however, limiting the certainty of these findings. Our findings indicate that positive psychology-based interventions can significantly improve psychological well-being in prison settings.
The diatonic sound of scent imagery
This research investigates crossmodal correspondences between auditory stimuli, specifically musical modes, and olfactory mental imagery, represented by fragrance families. Building on the emerging literature on crossmodal correspondences, this research explores different mechanisms that might help to explain these crossmodal correspondences such as their shared connotative meaning and identity-based meaning. The first study evaluated the fragrance families and subfamilies and musical modes and assessed potential mechanisms behind these associations. The second study examined the associations between the musical modes and fragrance families and subfamilies through a matching task. The results revealed consistent matches between different musical modes and corresponding fragrance families and subfamilies, indicating a crossmodal association between auditory and olfactory mental imagery. What is more, major modes were perceived as brighter and less intense, and were more liked than minor modes, with floral and fresh fragrances similarly rated as brighter and more liked than oriental and woody fragrances. These results suggest that crossmodal correspondences between auditory and olfactory stimuli are influenced by brightness, intensity, and hedonic factors. Understanding such crossmodal associations can potentially benefit various fields, including marketing, product design, and those interested in creating multisensory experiences.
Language and economic behaviour: Future tense use causes less not more temporal discounting
Previous studies have found cross-cultural correlations between linguistic obligations for talking about future events and economic decisions like saving money. The hypothesis is that a grammatical obligation to use the future tense (e.g. will) causes speakers to perceive future rewards as temporally distal and therefore less valuable (“temporal discounting”). However, no studies have tested whether speakers actually temporally discount as a function of the extent to which they use the future tense. We present two studies which use a novel language-elicitation paradigm to do this, involving speakers of English (which obliges the future tense) and Dutch (which does not). We used mediation analysis to test how language-level differences in the grammatical obligation to use the future tense impact economic decisions via individual language use habits. However, we found that English speakers who habitually make greater use of the future tense actually discount less, not more. These results suggest obligatory future tense use is not responsible for previously-reported cross-cultural correlations. Instead, we suggest that a better explanation involves modal notions of certainty (the probability of an event occurring) rather than temporal distance (when an event will occur). Future tenses express high certainty, which makes the correct prediction that obligatory tense marking should cause less discounting. In contrast, the cross-cultural differences may be driven by variation in other aspects of future time reference, such as low-certainty modal terminology (e.g. may, might).
Research assistants' experiences recruiting patients with psychosis into clinical trials: a qualitative study.
OBJECTIVES: Treatments for patients diagnosed with psychosis need to be improved. Clinical trials are an important way of assessing the efficacy of new treatments. However, recruiting patients into trials is challenging. This study sought to better understand the reasons for this from the perspective of research assistants. DESIGN: A qualitative study underpinned by a critical realist ontology and contextualist epistemology. METHODS: Research assistants who had recruited patients with psychosis into trials, primarily of psychological interventions, were interviewed. Reflexive thematic analysis was used to identify themes. RESULTS: Overarching themes representing four types of factors influencing recruitment of patients with psychosis into clinical trials were generated: patient, clinical team, research team, and NHS infrastructure. Patients largely wished to take part in trials but needed time to build trust with research assistants. Clinical teams held the power in suggesting patients for trials; therefore, it was essential for research teams to build strong relationships with clinical staff. Research teams recruiting into trials benefited from lived experience expertise, support systems, and institutional knowledge. A key NHS infrastructure factor was that mental health staff had limited time to consider trials for their patients. CONCLUSIONS: Trial participation needs to be made more accessible to patients with psychosis, who often want to take part but lack opportunities. Methods of increasing accessibility could include identifying and addressing barriers to referral from clinical teams, employing multiple recruitment strategies, and flexible appointment formats. Qualitative research with clinical teams and patients will also help in developing the understanding of barriers to recruitment.
Relationship of plasma biomarkers to digital cognitive tests in Alzheimer's disease.
INTRODUCTION: A major limitation in Alzheimer's disease (AD) research is the lack of the ability to measure cognitive performance at scale-robustly, remotely, and frequently. Currently, there are no established online digital platforms validated against plasma biomarkers of AD. METHODS: We used a novel web-based platform that assessed different cognitive functions in AD patients (N = 46) and elderly controls (N = 53) who were also evaluated for plasma biomarkers (amyloid beta 42/40 ratio, phosphorylated tau ([p-tau]181, glial fibrillary acidic protein, neurofilament light chain). Their cognitive performance was compared to a second, larger group of elderly controls (N = 352). RESULTS: Patients with AD were significantly impaired across all digital cognitive tests, with performance correlating with plasma biomarker levels, particularly p-tau181. The combination of p-tau181 and the single best-performing digital test achieved high accuracy in group classification. DISCUSSION: These findings show how online testing can now be deployed in patients with AD to measure cognitive function effectively and related to blood biomarkers of the disease. HIGHLIGHTS: This is the first study comparing online digital testing to plasma biomarkers.Alzheimer's disease patients and two independent cohorts of elderly controls were assessed.Cognitive performance correlated with plasma biomarkers, particularly phosphorylated tau (p-tau)181.Glial fibrillary acidic protein and neurofilament light chain, and less so the amyloid beta 42/40 ratio, were also associated with performance.The best cognitive metric performed at par to p-tau181 in group classification.
Generalization of auditory expertise in audio engineers and instrumental musicians.
From auditory perception to general cognition, the ability to play a musical instrument has been associated with skills both related and unrelated to music. However, it is unclear if these effects are bound to the specific characteristics of musical instrument training, as little attention has been paid to other populations such as audio engineers and designers whose auditory expertise may match or surpass that of musicians in specific auditory tasks or more naturalistic acoustic scenarios. We explored this possibility by comparing students of audio engineering (n = 20) to matched conservatory-trained instrumentalists (n = 24) and to naive controls (n = 20) on measures of auditory discrimination, auditory scene analysis, and speech in noise perception. We found that audio engineers and performing musicians had generally lower psychophysical thresholds than controls, with pitch perception showing the largest effect size. Compared to controls, audio engineers could better memorise and recall auditory scenes composed of non-musical sounds, whereas instrumental musicians performed best in a sustained selective attention task with two competing streams of tones. Finally, in a diotic speech-in-babble task, musicians showed lower signal-to-noise-ratio thresholds than both controls and engineers; however, a follow-up online study did not replicate this musician advantage. We also observed differences in personality that might account for group-based self-selection biases. Overall, we showed that investigating a wider range of forms of auditory expertise can help us corroborate (or challenge) the specificity of the advantages previously associated with musical instrument training.
Sustained pupil responses are modulated by predictability of auditory sequences
The brain is highly sensitive to auditory regularities and exploits the predictable order of sounds in many situations, from parsing complex auditory scenes, to the acquisition of language. To understand the impact of stimulus predictability on perception, it is important to determine how the detection of predictable structure influences processing and attention. Here we use pupillometry to gain insight into the effect of sensory regularity on arousal. Pupillometry is a commonly used measure of salience and processing effort, with more perceptually salient or perceptually demanding stimuli consistently associated with larger pupil diameters. In two experiments we tracked human listeners’ pupil dynamics while they listened to sequences of 50ms tone pips of different frequencies. The order of the tone pips was either random, contained deterministic (fully predictable) regularities (experiment 1, n = 18, 11 female) or had a probabilistic regularity structure (experiment 2, n = 20, 17 female). The sequences were rapid, preventing conscious tracking of sequence structure thus allowing us to focus on the automatic extraction of different types of regularities. We hypothesized that if regularity facilitates processing by reducing processing demands, a smaller pupil diameter would be seen in response to regular relative to random patterns. Conversely, if regularity is associated with heightened arousal and attention (i.e. engages processing resources) the opposite pattern would be expected. In both experiments we observed a smaller sustained (tonic) pupil diameter for regular compared with random sequences, consistent with the former hypothesis and confirming that predictability facilitates sequence processing.
Dissociable behavioural signatures of co-existing impulsivity and apathy in decision-making.
Apathy and impulsivity are expressed in a wide range of neuropsychiatric disorders, and, to a less severe extent, in healthy people too. Although traditionally considered to be opposite extremes of a single motivational spectrum, recent epidemiological questionnaire-based data suggest that both traits can in fact co-exist within the same individual. Here, we sought to investigate the relationship between these constructs in healthy people within a controlled task environment that examines the ability to make a decision under temporal uncertainty and measures the vigour of the response. Sixty participants performed a new version of the Traffic Light Task and completed self-report questionnaire measures of apathy and impulsivity. The task required individuals to make rapid decision-making for time-sensitive reward by squeezing a hand-held dynamometer as quickly as possible after a predictable event occurred (a traffic light turning green). Although apathy and impulsivity were positively correlated in questionnaire assessments, the two traits were associated with distinct behavioural signatures on the task. Impulsivity was expressed as an inflexible tendency to generate rapid anticipatory responses, regardless of cost-benefit information. Apathy, on the other hand, was associated with a blunted effect of reward on response vigour. These findings reveal how apathy and impulsivity are related to distinct dimensions of goal-directed behaviour, explaining how these traits might co-exist in the same individuals.
Cognitive behavioural therapy for sleep problems in psychosis: systematic review of effectiveness and acceptability.
BACKGROUND: Sleep problems are common among people with psychosis. Research suggests poor sleep is causally related to psychosis, anxiety and depression. AIMS: This review investigates the effectiveness and acceptability of cognitive-behavioural therapy (CBT) in targeting sleep problems in people with and at risk of psychosis. METHOD: Four databases were searched in line with PRISMA guidelines. Eligible studies either evaluated (a) CBT targeting sleep problems in people with or at risk of psychosis, or (b) subjective experiences of this treatment. Articles not published in peer-review journals were excluded. Treatment effectiveness was investigated for sleep, psychosis and other clinical outcomes. Acceptability was evaluated using qualitative data, drop-out rates, adverse events and relevant questionnaires. Adaptations to standard treatment protocols were described. Research quality was appraised using Cochrane Risk of Bias tools for randomised and non-randomised trials, and a checklist was developed for qualitative papers. RESULTS: Of the 975 records identified, 14 were eligible. The most common CBT target was insomnia. Treatment protocols were typically adapted by omitting sleep restriction. Large effect sizes were reported for sleep outcomes; however, effects for other clinical outcomes were less clear. Qualitative data and acceptability outcomes suggest that treatment was received positively by participants. CONCLUSIONS: CBT is an effective and acceptable treatment for sleep problems in people with and at risk of psychosis. However, our conclusions are limited by few good-quality studies and small samples. Further gold-standard research is required to inform evidence-based guidelines.