A review of neuroimaging studies of race-related prejudice: does amygdala response reflect threat?

Prejudice is an enduring and pervasive aspect of human cognition. An emergent trend in modern psychology has focused on understanding how cognition is linked to neural function, leading researchers to investigate the neural correlates of prejudice. Research in this area, using racial group memberships, quickly highlighted the amygdala as a neural structure of importance. In this article, we offer a critical review of social neuroscientific studies of the amygdala in race-related prejudice. Rather than the dominant interpretation that amygdala activity reflects a racial or outgroup bias per se, we argue that the observed pattern of sensitivity in this literature is best considered in terms of potential threat. More specifically, we argue that negative culturally-learned associations between black males and potential threat better explain the observed pattern of amygdala activity. Finally, we consider future directions for the field, and offer specific experiments and predictions to directly address unanswered questions

Sertraline and mirtazapine versus placebo in subgroups of depression in dementia: findings from the HTA-SADD randomized controlled trial

Objective Studies have shown that antidepressants are no better than placebo in treating depression in dementia. The authors examined antidepressant efficacy in subgroups of depression in dementia with different depressive symptom profiles. Methods This study focuses on exploratory secondary analyses on the randomized, parallel-group, double-blind, placebo-controlled Health Technology Assessment Study of the Use of Antidepressants for Depression in Dementia (HTA-SADD) trial. The setting included old-age psychiatry services in nine centers in England. The participants included 326 patients meeting National Institute of Neurological and Communicative Disorders and Stroke/Alzheimer's Disease and Related Disorders Association probable/possible Alzheimer disease criteria, and Cornell Scale for Depression in Dementia (CSDD) scores of 8 or more. Intervention was placebo (n = 111), sertraline (n = 107), or mirtazapine (n = 108). Latent class analyses (LCA) on baseline CSDD items clustered participants into symptom-based subgroups. Mixed-model analysis evaluated CSDD improvement at 13 and 39 weeks by randomization in each subgroup. Results LCA yielded 4 subgroups: severe (n = 34), psychological (n = 86), affective (n = 129), and somatic (n = 77). Mirtazapine, but not sertraline, outperformed placebo in the psychological subgroup at week 13 (adjusted estimate: –2.77 [standard error (SE) 1.16; 95% confidence interval: –5.09 to –0.46]), which remained, but lost statistical significance at week 39 (adjusted estimate: –2.97 [SE 1.59; 95% confidence interval: –6.15 to 0.20]). Neither sertraline nor mirtazapine outperformed placebo in the other subgroups. Conclusion Because of the exploratory nature of the analyses and the small sample sizes for subgroup analysis there is the need for caution in interpreting these data. Replication of the potential effects of mirtazapine in the subgroup of those with depression in dementia with “psychological” symptoms would be valuable. These data should not change clinical practice, but future trials should consider stratifying types of depression in dementia in secondary analyses

Confidence and insight into working memories are shaped by attention and recent performance

Working memory is capacity limited, and our ability to access information from working memory is variable, but selective attention to working memory contents can improve performance. People are able to make introspective judgments regarding the quality of their memories, and these judgments are linked to objective memory performance. However, it remains unknown whether benefits of internally directed attention on memory performance occur alongside commensurate changes in introspective judgments. Across two experiments, we used retrospective cues (retrocues) during working-memory maintenance to direct attention to items in memory. We then examined their consequence on introspective judgments. In the second experiment, we provided trial-wise feedback on performance. We found that selective attention improved confidence judgments and not just performance of the probed item. We were also able to judge participants' genuine insight into working-memory contents through the correlation between confidence judgments and memory quality. Neurophysiologically, alpha desynchronization correlated first with memory error and then confidence during retrocueing, suggesting a sequential process of attentional enhancement of memory contents and introspective insight. Furthermore, we showed that participants can use feedback on the accuracy of confidence judgments to update their beliefs across time, according to performance. Our results emphasize flexibility in working memory by showing we can selectively modulate our confidence about its contents based on internally directed attention or objective feedback

Human gaze tracks attentional focusing in memorized visual space

Brain areas that control gaze are also recruited for covert shifts of spatial attention. In the external space of perception, there is a natural ecological link between the control of gaze and spatial attention, as information sampled at covertly attended locations can inform where to look next. Attention can also be directed internally to representations held within the spatial layout of visual working memory. In such cases, the incentive for using attention to direct gaze disappears, as there are no external targets to scan. Here we investigate whether the oculomotor system of the brain also participates in attention focusing within the internal space of memory. Paradoxically, we reveal this participation through gaze behaviour itself. We demonstrate that selecting an item from visual working memory biases gaze in the direction of the memorized location of that item, despite there being nothing to look at and location memory never explicitly being probed. This retrospective ‘gaze bias’ occurs only when an item is not already in the internal focus of attention, and it predicts the performance benefit associated with the focusing of internal attention. We conclude that the oculomotor system also participates in focusing attention within memorized space, leaving traces all the way to the eyes

Altered functional brain connectivity in children and young people with paediatric opsoclonus-myoclonus syndrome (OMS)

Aim: Opsoclonus-Myoclonus syndrome (OMS) is a rare, poorly understood condition that can result in long-term cognitive, behavioural and motor sequelae. Several studies have investigated structural brain changes associated with this condition, but little is known about changes in function. This study aimed to investigate changes in brain functional connectivity in patients with OMS. Method: Seven patients with OMS and 10 age-matched control participants underwent 3T magnetic resonance imaging (MRI) to acquire resting state functional MRI data (whole-brain echo-planar images; 2mm isotropic voxels; multiband factor x 2) for a cross-sectional study. A seed-based analysis identified brain regions in which signal changes over time correlated with the cerebellum. Model-free analysis was employed to determine brain networks showing altered connectivity. Results: In OMS patients the motor cortex showed significantly reduced connectivity, and the occipito-parietal region significantly increased connectivity with the cerebellum relative to the control group. A model-free analysis also showed extensive connectivity within a visual network, including the cerebellum and basal ganglia, not present in controls. No other networks showed any differences between groups. Interpretation: OMS patients showed reduced connectivity between the cerebellum and motor cortex, but increased connectivity with occipitoparietal regions. This pattern of change supports widespread brain involvement in OMS

Cytogenetic effects of Tribulus terrestris L. on meristematic cells of Allium cepa L. and Vicia faba L.

Tribulus terrestris is a plant of the Zygophyllaceae family frequently used worldwide to treat various diseases due to the therapeutic effects of its pharmacological components. This study examines the cytotoxic and genotoxic effects of T. terrestris using two plant models, Allium cepa and Vicia faba. Extracts of 0.00625, 0.0125, 0.025, 0.05 and 0.1mg/mL were tested on meristematic cells of A. cepa and V. faba roots. This assessment includes the study of root growth, structure and coloration, as well as the determination of the mitotic index (MI) and chromosomal aberrations (CAs) as accurate indicators of toxicity. Our results showed a significant decrease in the mean length of roots treated with 0.025, 0.05 and 0.1 mg/ml for A. cepa and 0.1 mg/ml for V. faba. Cytotoxicity and genotoxicity results showed a significant decrease in MI from 0.025 mg/ml in A. cepa and from 0.05 mg/ml in V. faba, and this decrease in MI is linked to the increase in concentration and treatment time with T. terrestris. Furthermore, a significant increase in CAs was observed in A. cepa and V. faba from the 0.025 mg/ml concentration. The significant reduction in MI and CAs abundance suggests the genotoxicity of T. terrestris. Therefore, T. terrestris is a medicinal plant that should be used with caution, appropriately and based on essential therapeutic needs

Potential use of Bacillus paramycoides for the production of the biopolymer polyhydroxybutyrate from leftover carob fruit agro-waste

This study was designed to investigate, at a laboratory scale, the possibility of valorizing the leftover carob fruits to produce the eco-friendly biopolymer polyhydroxybutyrate (PHB) by using the bacterial strain Bacillus paramycoides, which has been isolated from the botanical garden of Skikda University in Algeria. The PHB production was tested under various conditions: a pH of 3-8, temperature range of 30-44 celcius, carob extracted molasses concentration of 2-8% v/v, an incubation time of 24-96 h and an agitation speed of 150-300 rpm. The effects of different nitrogen sources and carob extracted molasses treatment types were also investigated. The PHB concentration was determined quantitatively as crotonic acid by measuring the absorbance at 300 nm. Cell growth was quantified by measuring the density of the culture at 600 nm. The presence of PHB was confirmed by applying high-performance liquid chromatography (HPLC) using an Aminex HPX-87H and implementing gas chromatography analysis. The best yield of PHB synthesis was obtained by using 6% v/v of 5 M H2SO4 treated with carob molasses as a carbon source, with peptone as a nitrogen source; incubation was conducted at 37 degrees C for 96 hat an agitation speed of 300 rpm (114.95 mg/L). The HPLC analysis confirmed the synthesis of PHB by B. paramycoides to have a chromatogram retention time of 22.5 min. Carob waste was successfully valorized to PHB

Comprehensive review:Computational modelling of Schizophrenia

Computational modelling has been used to address: (1) the variety of symptoms observed in schizophrenia using abstract models of behavior (e.g. Bayesian models - top-down descriptive models of psychopathology); (2) the causes of these symptoms using biologically realistic models involving abnormal neuromodulation and/or receptor imbalance (e.g. connectionist and neural networks - bottom-up realistic models of neural processes). These different levels of analysis have been used to answer different questions (i.e. understanding behavioral vs. neurobiological anomalies) about the nature of the disorder. As such, these computational studies have mostly supported diverging hypotheses of schizophrenia's pathophysiology, resulting in a literature that is not always expanding coherently. Some of these hypotheses are however ripe for revision using novel empirical evidence.Here we present a review that first synthesizes the literature of computational modelling for schizophrenia and psychotic symptoms into categories supporting the dopamine, glutamate, GABA, dysconnection and Bayesian inference hypotheses respectively. Secondly, we compare model predictions against the accumulated empirical evidence and finally we identify specific hypotheses that have been left relatively under-investigated

COVID-19 Confinement and Health Risk Behaviors in Spain

The World Health Organization (WHO) has declared a world pandemic due to COVID-19. In response, most affected countries have enacted measures involving compulsory confinement and restrictions on free movement, which likely influence citizens'' lifestyles. This study investigates changes in health risk behaviors (HRBs) with duration of confinement. An online cross-sectional survey served to collect data about the Spanish adult population regarding health behaviors during the first 3 weeks of confinement. A large sample of participants (N = 2, 741) (51.8% women; mean age 34.2 years [SD 13.0]) from all Spanish regions completed the survey. Binomial logistic regressions adjusted for socioeconomic characteristics (i.e., gender, age, civil status, education, and occupation), body mass index (BMI), previous HRBs, and confinement context (i.e., solitude and exposure to COVID-19) were conducted to investigate associations between the number of weeks confined and a set of six HRBs (physical activity, alcohol consumption, fresh fruit and vegetable consumption, smoking, screen exposure, and sleep hours). When adjusted, we observed significantly lower odds of experiencing a higher number of HRBs than before confinement overall in a time-dependent fashion: OR 0.63; 95% CI: 0.49–0.81 for the second and OR 0.47; 95% CI: 0.36–0.61 for the third week of confinement. These results were equally consistent in all age and gender subgroup analyses. The present study indicates that changes toward a higher number of HRBs than before confinement, as well as the prevalence of each HRB except screen exposure, decreased during the first 3 weeks of COVID-19 confinement, and thus the Spanish adult population may have adapted to the new situational context by gradually improving their health behaviors

TRPV4 channels mediate the infrared laser-evoked response in sensory neurons

Infrared laser irradiation has been established as an appropriate stimulus for primary sensory neurons under conditions where sensory receptor cells are impaired or lost. Yet, development of clinical applications has been impeded by lack of information about the molecular mechanisms underlying the laser-induced neural response. Here, we directly address this question through pharmacological characterization of the biological response evoked by midinfrared irradiation of isolated retinal and vestibular ganglion cells from rodents. Whole cell patch-clamp recordings reveal that both voltage-gated calcium and sodium channels contribute to the laser-evoked neuronal voltage variations (LEVV). In addition, selective blockade of the LEVV by micromolar concentrations of ruthenium red and RN 1734 identifies thermosensitive transient receptor potential vanilloid channels as the primary effectors of the chain reaction triggered by midinfrared laser irradiation. These results have the potential to facilitate greatly the design of future prosthetic devices aimed at restoring neurosensory capacities in disabled patients