Augmenting Virtual Reality Exposure Therapy for Social and Intergroup Anxiety With Transcranial Direct Current Stimulation

OBJECTIVES

Exposure therapy is a cornerstone of social anxiety treatment, yet not all patients respond. Symptoms in certain social situations, including intergroup (ie, out-group) contexts, may be particularly resistant to treatment. Exposure therapy outcomes may be improved by stimulating neural areas associated with safety learning, such as the medial prefrontal cortex (mPFC). The mPFC also plays an important role in identifying others as similar to oneself. We hypothesized that targeting the mPFC during exposure therapy would reduce intergroup anxiety and social anxiety.

METHODS

Participants (N = 31) with the public speaking subtype of social anxiety received active (anodal) or sham transcranial direct current stimulation (tDCS) targeting the mPFC during exposure therapy. Exposure therapy consisted of giving speeches to audiences in virtual reality. To target intergroup anxiety, half of the public speaking exposure trials were conducted with out-group audiences, defined in this study as audiences of a different ethnicity.

RESULTS

Contrary to hypotheses, tDCS did not facilitate symptom reduction. Some evidence even suggested that tDCS temporarily increased in-group favoritism, although these effects dissipated at 1-month follow-up. In addition, collapsing across all participants, we found reductions across time for public speaking anxiety and intergroup anxiety.

CONCLUSIONS

The data provide evidence that standard exposure therapy techniques for social anxiety can be adapted to target intergroup anxiety. Transcranial direct current stimulation targeting the mPFC may boost safety signaling, but only in contexts previously conditioned to signal safety, such as an in-group context.

People with high schizotypy experience more illusions in the Pattern Glare Test: Consistent with the hyperexcitability hypothesis

Individuals diagnosed with schizophrenia spectrum disorders (SSD) exhibit a constellation of sensory and perceptual impairments, including hyporeactivity to external input. However, individuals with SSD also report subjective experiences of sensory flooding, suggesting sensory hyperexcitability. To identify the extent to which behavioural indices of hyperexcitability are related to non-psychotic symptoms of schizophrenia, we tested a non-clinical population measured for schizophrenia-like traits (schizotypy), and a behavioural measure of sensory hyperexcitability, specifically the number of illusions seen in the Pattern Glare Test. Two samples totaling 913 individuals completed an online version of the Schizotypal Personality Questionnaire - Brief Revised (SPQ-BR) and the Pattern Glare Test. Individuals with higher schizotypy traits reported more illusions in the Pattern Glare Test. Additionally, one of the three SPQ-BR factors, the disorganized factor, significantly predicted the number of illusions reported. These data illustrate the potential for research in non-clinical samples to inform clinically relevant research.

Caught in the ACTS: Defining Abstract Cognitive Task Sequences as an Independent Process

Cognitive neuroscience currently conflates the study of serial responses (e.g., delay match to sample/nonsample, n-back) with the study of sequential operations. In this essay, our goal is to define and disentangle the latter, termed abstract cognitive task sequences (ACTS). Existing literatures address tasks requiring serial events, including procedural learning of implicit motor responses, statistical learning of predictive relationships, and judgments of attributes. These findings do not describe the behavior and underlying mechanism required to succeed at remembering to evaluate color, then shape; or to multiply, then add. A new literature is needed to characterize these sorts of second-order cognitive demands of studying a sequence of operations. Our second goal is to characterize gaps in knowledge related to ACTS that merit further investigation. In the following sections, we define more precisely what we mean by ACTS and suggest research questions' further investigation would be positioned to address.

Impaired visual working memory and reduced connectivity in undergraduates with a history of mild traumatic brain injury

Mild traumatic brain injury (mTBI), or concussion, accounts for 85% of all TBIs. Yet survivors anticipate full cognitive recovery within several months of injury, if not sooner, dependent upon the specific outcome/measure. Recovery is variable and deficits in executive function, e.g., working memory (WM) can persist years post-mTBI. We tested whether cognitive deficits persist in otherwise healthy undergraduates, as a conservative indicator for mTBI survivors at large. We collected WM performance (change detection, n-back tasks) using various stimuli (shapes, locations, letters; aurally presented numbers and letters), and wide-ranging cognitive assessments (e.g., RBANS). We replicated the observation of a general visual WM deficit, with preserved auditory WM. Surprisingly, visual WM deficits were equivalent in participants with a history of mTBI (mean 4.3 years post-injury) and in undergraduates with recent sports-related mTBI (mean 17 days post-injury). In seeking the underlying mechanism of these behavioral deficits, we collected resting state fMRI (rsfMRI) and EEG (rsEEG). RsfMRI revealed significantly reduced connectivity within WM-relevant networks (default mode, central executive, dorsal attention, salience), whereas rsEEG identified no differences (modularity, global efficiency, local efficiency). In summary, otherwise healthy current undergraduates with a history of mTBI present behavioral deficits with evidence of persistent disconnection long after full recovery is expected.

No tDCS augmented working memory training benefit in undergraduates rewarded with course credit

BACKGROUND

The goal of working memory (WM) training is to expand capacity of this executive function. Transcranial direct current stimulation (tDCS) paired with WM training is more consistent than either alone. We have reported that tDCS targeting frontal and/or parietal regions enhanced theta phase locking, reduced alpha power, and strengthened theta-gamma phase amplitude coupling.

OBJECTIVE

To determine whether tDCS to frontal or parietal sites optimized WM training gains we pre-registered a tDCS-WM training study.

METHODS

80 undergraduates were randomly assigned to one of four anodal tDCS montages: frontal (F4), parietal (P4), alternating (P4-F4), and sham (P4 or F4). Participants completed 5-training sessions over one week and returned for follow-up testing after 30 days of no-contact.

RESULTS

No group showed significant improvement in trained or transfer task performance at the end of training nor at follow-up.

CONCLUSIONS

This null finding marks a failure to replicate in undergraduates training benefits observed in graduate students. We argue that motivation is essential to elicit improved performance in training protocols.

TM1-2 Diffuse low grade glioma after the 2016 WHO update, seizure characteristics, imaging correlates and outcomes

Objectives

Seizures are a common presenting symptom in patients with low grade glioma (LGG). Exact mechanisms of epileptogenesis are unknown and the influence of radiological and histological characteristics are not well studied, particularly after the 2016 WHO reclassification of gliomas. We aimed to define predictors of seizure development and outcome in patients with LGG.

Design

Retrospective single institution case series.

Subjects

63 patients who underwent resection of supratentorial LGG in a single institution, 45 presented with seizures.

Methods

Retrospective analysis of patient records to assess seizure outcome and other demographics including radiological variables, tumour characteristics, type of surgery and histology based on the 2016 WHO update.

Results

After surgery, 33 patients (73%) who presented with seizures were Engel class I at median follow up of 43 months. Complete and near total resection were associated with improved Engel class compared to subtotal resection. Awake craniotomy gave improved seizure outcomes compared to under general anaesthesia (84% vs 65%). Molecular genetics did not predict seizure outcome. Updated histology did not predict seizures at diagnosis, only tumour heterogeneousity on initial MRI (p=0.043). Tumour volume at presentation impacted EOR but not seizure outcome.

Conclusions

Seizure outcome is directly related to EOR. Tumour histology based on molecular genetics did not predict seizure development or outcome. Use of awake craniotomy results in greater EOR and improved Engel class.

Intraepithelial lymphocytes: exploring the Third Way in immunology

Locally resident intraepithelial lymphocytes (IELs) are primarily T cells with potent cytolytic and immunoregulatory capacities, which they use to sustain epithelial integrity. Here, we consider that most IEL compartments comprise a variable mixture of two cell types: T cells primed to conventional antigen in the systemic compartment and T cells with ill-defined reactivities and origins, whose properties seem to place them mid-way between the adaptive and innate immune responses. We review the capacity of IELs to limit the dissemination of infectious pathogens and malignant cells and to control the infiltration of epithelial surfaces by systemic cells. An improved characterization of IELs would seem essential if we are to understand how immune responses and immunopathologies develop at body surfaces.

Biological insights into TCRgammadelta+ and TCRalphabeta+ intraepithelial lymphocytes provided by serial analysis of gene expression (SAGE)

Intraepithelial lymphocytes (IELs) are abundant, evolutionarily conserved T cells, commonly enriched in T cell receptor (TCR) gammadelta expression. However, their primary functional potential and constitutive activation state are incompletely understood. To address this, serial analysis of gene expression (SAGE) was applied to murine TCRgammadelta+ and TCRalphabeta+ intestinal IELs directly ex vivo, identifying 15,574 unique transcripts that collectively portray an "activated yet resting," Th1-skewed, cytolytic, and immunoregulatory phenotype applicable to multiple subsets of gut IELs. Expression of granzymes, Fas ligand, RANTES, prothymosin beta4, junB, RGS1, Btg1, and related molecules is high, whereas expression of conventional cytokines and high-affinity cytokine receptors is low. Differentially expressed genes readily identify heterogeneity among TCRalphabeta+ IELs, whereas differences between resident TCRgammadelta+ IELs and TCRalphabeta+ IELs are less obvious.

Failure to thrive and its relationship to serum vitamin A levels and diet

Serum vitamin A and retinol-binding protein (RBP) levels were determined in a group of 34 children between 1 and 4 years of age with failure to thrive and in 34 age- and sex-matched controls. Both groups of children were also assessed in respect of anthropometry and diet. Vitamin A levels in patients (0-32.2 micrograms/100 ml; median 16.9 micrograms/100 ml) did not differ significantly from controls (6.4-47.2 micrograms/100 ml; median 16.1 micrograms/100ml). Fourteen patients (42%) and 4 controls (12%) had vitamin A levels below 10 micrograms/100 ml. RBP levels in patients (0.45-3.50 mg/100 ml; median 2.17 mg/100 ml) also did not differ significantly from those in controls (1.21-3.66 mg/100 ml; median 2.06 mg/100 ml). No clinical features of vitamin A deficiency were detected. Weight and height for age, weight for height, mid-upper arm circumference and head circumference differed significantly between patients and controls (P < 0.0001 in each instance). Although within the recommendations for intake, patients had a significantly lower intake of the essential fatty acid C 18:2 (N = 6) (linoleic acid) and vitamin A. In view of the current proposed relationship between vitamin A status and infectious diseases, the prevalence of biochemical vitamin A deficiency in children in the Cape Town community studied may contribute to the morbidity and mortality associated with infectious diseases in the area to a greater degree than has been suspected.

Antenatal ultrasonographic findings in tuberous sclerosis. Report of 2 cases

Tuberous sclerosis is an autosomal dominant disease with variable expression. The initial manifestations have been reported at varying stages postnatally, but little is known about the fetal age at which the disease may be detected. The antenatal ultrasonographic features in 2 affected fetuses, at 40 and 26 weeks respectively, are reported. The second case appears unique because of the early fetal involvement and the abnormally large brain tumour.

Properties of the nicotinamide adenine dinucleotide phosphate-dependent aldehyde reductase from pig kidney. Amino acid composition, reactivity of cysteinyl residues, and stereochemistry of D-glyceraldehyde reduction

Some physical and chemical properties of the monomeric NADP+-dependent aldehyde reductase (previously called TPN-L-hexonate dehydrogenase or D-glucuronate reductase) from pig kidney have been examined. The amino acid composition has been determined. Four of the five thiol groups react with p-mercuribenzoate at pH 7, with no resulting loss of catalytic activity. High concentrations of p-mercuribenzoate cause complete enzyme inhibition, which can be partly reversed by addition of aldehyde reductase is low (9%, estimated from the ellipticity at 208 nm), and 70 to 80% of the tyrosine and tryptophan residues aare buried within the molecule. One molecule of NADPH binds to the enzyme (Kp equal 25 muM), causing a blue shift and enhancement of the coenzyme fluorescence, and suggesting that the environment of the active site is hydrophobic. In the reduction of D-glyceraldehyde, catalyzed by aldehyde reductase, the pro-4R "A" hydrogen of NADPH attacks the re face of the carbonyl group. This stereospecificity is the same as in the reductions of D-glyceraldehyde and acetaldehyde effected by rabbit muscle dehydrogenase and liver alcohol dehydrogenase, respectively.