A new comparator account of auditory verbal hallucinations: how motor prediction can plausibly contribute to the sense of agency for inner speech

The comparator account holds that processes of motor prediction contribute to the sense of agency by attenuating incoming sensory information and that disruptions to this process contribute to misattributions of agency in schizophrenia. Over the last 25 years this simple and powerful model has gained widespread support not only as it relates to bodily actions but also as an account of misattributions of agency for inner speech, potentially explaining the etiology of auditory verbal hallucination (AVH). In this paper we provide a detailed analysis of the traditional comparator account for inner speech, pointing out serious problems with the specification of inner speech on which it is based and highlighting inconsistencies in the interpretation of the electrophysiological evidence commonly cited in its favor. In light of these analyses we propose a new comparator account of misattributed inner speech. The new account follows leading models of motor imagery in proposing that inner speech is not attenuated by motor prediction, but rather derived directly from it. We describe how failures of motor prediction would therefore directly affect the phenomenology of inner speech and trigger a mismatch in the comparison between motor prediction and motor intention, contributing to abnormal feelings of agency. We argue that the new account fits with the emerging phenomenological evidence that AVHs are both distinct from ordinary inner speech and heterogeneous. Finally, we explore the possibility that the new comparator account may extend to explain disruptions across a range of imagistic modalities, and outline avenues for future research.

Access to a Car and the Self-Reported Health and Mental Health of People Aged 65 and Older in Northern Ireland

This article examines relationships between access to a car and the self- reported health and mental health of older people. The analysis is based on a sample of N 1⁄4 65,601 individuals aged 65 years and older from the Northern Ireland Longitudinal Study linked to 2001 and 2011 census returns. The findings from hierarchical linear and binary logistic multilevel path models indicate that having no access to a car is related to a considerable health and mental health disadvantage particularly for older people who live alone. Rural–urban health and mental health differences are mediated by access to a car. The findings support approaches that emphasize the importance of autonomy and independence for the well-being of older people and indicate that not having access to a car can be a problem for older people not only in rural but also in intermediate and urban areas, if no sufficient alternative forms of mobility are provided.

Sonification as Concurrent Augmented Feedback for Motor Skill Learning and the Importance of Mapping Design

In recent years, sonification of movement has emerged as a viable method for the provision of feedback in motor learning. Despite some experimental validation of its utility, controlled trials to test the usefulness of sonification in a motor learning context are still rare. As such, there are no accepted conventions for dealing with its implementation. This article addresses the question of how continuous movement information should be best presented as sound to be fed back to the learner. It is proposed that to establish effective approaches to using sonification in this context, consideration must be given to the processes that underlie motor learning, in particular the nature of the perceptual information available to the learner for performing the task at hand. Although sonification has much potential in movement performance enhancement, this potential is largely unrealised as of yet, in part due to the lack of a clear framework for sonification mapping: the relationship between movement and sound. By grounding mapping decisions in a firmer understanding of how perceptual information guides learning, and an embodied cognition stance in general, it is hoped that greater advances in use of sonification to enhance motor learning can be achieved.

Duration-dependent effects of the BDNF Val66Met polymorphism on anodal tDCS induced motor cortex plasticity in older adults: a group and individual perspective

The brain derived neurotrophic factor (BDNF) Val66Met polymorphism and stimulation duration are thought to play an important role in modulating motor cortex plasticity induced by non-invasive brain stimulation (NBS). In the present study we sought to determine whether these factors interact or exert independent effects in older adults. Fifty-four healthy older adults (mean age = 66.85 years) underwent two counterbalanced sessions of 1.5 mA anodal transcranial direct current stimulation (atDCS), applied over left M1 for either 10 or 20 min. Single pulse transcranial magnetic stimulation (TMS) was used to assess corticospinal excitability (CSE) before and every 5 min for 30 min following atDCS. On a group level, there was an interaction between stimulation duration and BDNF genotype, with Met carriers (n = 13) showing greater post-intervention potentiation of CSE compared to Val66Val homozygotes homozygotes (n = 37) following 20 min (p = 0.002) but not 10 min (p = 0.219) of stimulation. Moreover, Met carriers, but not Val/Val homozygotes, exhibited larger responses to TMS (p = 0.046) after 20 min atDCS, than following 10 min atDCS. On an individual level, two-step cluster analysis revealed a considerable degree of inter-individual variability, with under half of the total sample (42%) showing the expected potentiation of CSE in response to atDCS across both sessions. Intra-individual variability in response to different durations of atDCS was also apparent, with one-third of the total sample (34%) exhibiting LTP-like effects in one session but LTD-like effects in the other session. Both the inter-individual (p = 0.027) and intra-individual (p = 0.04) variability was associated with BDNF genotype. In older adults, the BDNF Val66Met polymorphism along with stimulation duration appears to play a role in modulating tDCS-induced motor cortex plasticity. The results may have implications for the design of NBS protocols for healthy and diseased aged populations.

Determining the optimal current direction of transcranial magnetic stimulation to induce motor responses in the tongue: A preliminary study of neurologically healthy individuals

Objective
To determine the optimal transcranial magnetic stimulation (TMS) coil direction for inducing motor responses in the tongue in a group of non-neurologically impaired participants.
Methods
Single-pulse TMS was delivered using a figure-of-eight Magstim 2002 TMS coil. Study 1 investigated the effect of eight different TMS coil directions on the motor-evoked potentials elicited in the tongue in eight adults. Study 2 examined active motor threshold levels at optimal TMS coil direction compared to a customarily-used ventral-caudal direction. Study 3 repeated the procedure of Study 1 at five different sites across the tongue motor cortex in one adult.
Results
Inter-individual variability in optimal direction was observed, with an optimal range of directions determined for the group. Active motor threshold was reduced when a participant's own optimal TMS coil direction was used compared to the ventral-caudal direction. A restricted range of optimal directions was identified across the five cortical positions tested.
Conclusions
There is a need to identify each individual's own optimal TMS coil direction in investigating tongue motor cortex function. A recommended procedure for determining optimal coil direction is described.
Significance
Optimized TMS procedures are needed so that TMS can be utilized in determining the underlying neurophysiological basis of various motor speech disorders.

Teamwork Efficiency and Company Size

We study how ownership structure and management objectives interact in determining the company size without assuming information constraints or any explicit costs of management. In symmetric agent economies, the optimal company size balances the returns to scale of the production function and the returns to collaboration efficiency. For a general class of payoff functions, we characterize the optimal company size, and we compare the optimal company size across different managerial objectives. We demonstrate the restrictiveness of common assumptions on effort aggregation (e.g., constant elasticity of effort substitution), and we show that common intuition (e.g., that corporate companies are more efficient and therefore will be larger than equal-share partnerships) might not hold in general.

Motor deficits in children with autism spectrum disorder: A cross-syndrome study

Recent research suggests that children with autism spectrum disorder (ASD) experience some level of motor difficulty, and that this may be associated with social communication skills. However, other studies show that children with language impairments, but without the social communication problems, are at risk of motor difficulties as well. The aim of the present study was to determine if children with ASD have syndrome specific motor deficits in comparison to children with specific language impairment (SLI). We used an independent groups design with three groups of children (8-10 years old) matched on age and nonverbal IQ; an ASD group, an SLI group, and a typically developing (TD) group. All of the children completed an individually administered, standardized motor assessment battery. We found that the TD group demonstrated significantly better motor skills than either the ASD or SLI groups. Detailed analyses of the motor subtests revealed that the ASD and SLI groups had very similar motor profiles across a range of fine and gross motor skills, with one exception. We conclude that children with ASD, and SLI, are at risk of clinically significant motor deficits. However, future behavioural and neurological studies of motor skills in children with ASD should include an SLI comparison group in order to identify possible autism specific deficits.

Review of Slavery by Any Other Name: African Life under Company Rule in Colonial Mozambique.

Book review of Slavery by Any Other Name: African Life under Company Rule in Colonial Mozambique, by Eric Allina, Charlottesville, University of Virginia Press, 2012, 255 pp., £44.50, ISBN 978-0-8139-3272-9.

Timing of response differentiation in human motor cortex during a speeded Go/No-go task

We explored the brain's ability to quickly prevent a pre-potent but unwanted motor response. To address this, transcranial magnetic stimulation was delivered over the motor cortex (hand representation) to probe excitability changes immediately after somatosensory cues prompted subjects to either move as fast as possible or withhold movement. Our results showed a difference in motor cortical excitability 90 ms post-stimulus contingent on cues to either promote or prevent movement. We suggest that our study design emphasizing response speed coupled with well-defined early probes allowed us to extend upon similar past investigations into the timing of response inhibition.