Faculty Bibliography

Human olfactory function requires the identification of everyday odors. A characteristic feature of olfaction is that most people find it hard to identify and name common odors, and when odors are presented simultaneously in mixtures, performance is even further compromised. Few studies have systematically assessed how training might enhance identification of single odors and mixtures. This study compared how odor identification training with either single odors or binary mixtures affected identification performance, as well as transfer effects to untrained tasks and odors. Twenty-seven healthy participants (22 F; 28.0 ± 4.7 years old) completed identification training of 8 odors using a list of 16 veridical names. The study included 8 training sessions, as well as pre-test and post-test evaluations. Results suggest notable effects of learning, as well as transfer to novel tasks and odors. Overall, training with single odors led to slightly better results than the binary mixture condition, suggesting that in novices, odor identification may be facilitated via consolidation of single odor objects, before learning to dissociate binary mixtures. Overall, odor identification may be trained to generate transfer of learning, although transfer effects were observed in both training methods. Our work suggests that odor identification abilities, while often limited, are highly trainable.

Why are certain individuals persistent in opposing immigration? The behavioral immune system framework implies that a psychological mechanism, which adapted to detect and avoid pathogen threats, is also reflected in contemporary social attitudes. Moreover, prejudice towards outgroups might be partially driven by implicit pathogen concerns related to the perceived dissimilarity with these groups' hygiene and food preparation practices. Disgust, a universal core emotion supposedly evolved to avoid pathogen threats, as well as olfaction, both play a pivotal role in evoking disgust. In an online study (N = 800), we investigated whether individual differences in body odor disgust sensitivity (BODS) correlate with negative attitudes towards a fictive refugee group. The data analysis plan and hypotheses were preregistered. Results show that body odor disgust sensitivity is associated with xenophobia: BODS was positively associated with negative attitudes towards the fictive group. This relationship was partially mediated by perceived dissimilarities of the group in terms of hygiene and food preparation. Our finding suggests prejudice might be rooted in sensory mechanisms.

Studies of risk and vulnerability processes may provide important ways of identifying new treatment targets - based on the principle that mending something is much easier if you know in what way it is broken. However, in our field, knowing its source may not always tell us about how to remediate impairment. Studies focusing on resilience may be more informative from this perspective. In this editorial I discuss four papers that highlight the value of resilience studies from a translational perspective - in particular contrasting the strengths and limitations of observational and experimental designs.

There is, in the content of the Journal, an embarrassment of riches, and picking a "best" seems to demand a certain qualification: is the "best" the most interesting, most surprising, most educational, most important, most provocative, most enjoyable? How to choose? We are hardly unbiased and can admit to a special affection for the ones that we and the authors worked hardest on, hammering version after version into shape. Acknowledging these biases, here are the 2018 articles that we think deserve your attention or at least a second read.

Melatonin secretion and polysomnography (PSG) were compared among a group of healthy adolescents who were at high familial risk for bipolar disorder (HR) and a second group at low familial risk (LR). Adolescent participants (n = 12) were a mean age 14 ± 2.3 years and included 8 females and 4 males. Saliva samples were collected under standardized condition light (red light) and following a 200 lux light exposure over two consecutive nights in a sleep laboratory. Red Light Melatonin onset (RLMO) was defined as saliva melatonin level exceeding the mean of the first 3 readings plus 2 standard deviations. Polysomnography was also completed during each night. HR youth, relative to LR, experienced a significantly earlier melatonin onset following 200 lux light exposure. Polysomnography revealed that LR youth, relative to HR, spent significantly more time in combined stages 3 and 4 (deep sleep) following red light exposure. Additionally, regardless of the group status (HR or LR), there was no significant difference in Red Light Melatonin Onset recorded at home or in the laboratory, implying its feasibility and reliability.

The findings of neuroimaging studies in children/adolescents with ADHD, and even those of previous meta-analyses, are divergent. Here, Activation Likelihood Estimation meta-analysis, following the current best-practice guidelines, was conducted. We searched multiple databases and traced the references up to June 2018. Then, we extracted the reported coordinates reflecting group comparison between ADHD and healthy subjects from 96 eligible studies, containing 1914 unique participants. The analysis of pooled structural and functional, sub-analyses restricted to modality, and in-/decreased contrast did not yield any significant findings. However, further sub-analyses in the task-fMRI experiments (neutral stimuli only) led to aberrant activity in the left pallidum/putamen and decreased activity (male subjects only) in the left inferior frontal gyrus. The overall findings indicate a lack of regional convergence in children/adolescents with ADHD, which might be due to heterogeneous clinical populations, various experimental design, preprocessing, statistical procedures in individual publications. Our results highlight the need for further high-powered investigations, but may also indicate ADHD pathophysiology might rest in network interactions rather than just regional abnormality.

OBJECTIVE:Disturbances in self-regulatory control are involved in the initiation and maintenance of addiction, including cannabis use disorder (CUD). In adults, chronic cannabis use is associated with disturbances in fronto-striatal circuits during tasks that require the engagement of self-regulatory control, including the resolution of cognitive conflict. Understudied are the behavioral and neural correlates of these processes earlier in the course of cannabis use, disentangled from effects of long-term use. The present study investigates the functioning of fronto-striatal circuits during the resolution of cognitive conflict in cannabis-using youth. METHOD/METHODS:Functional magnetic resonance imaging data was acquired from 28 cannabis-using (CU) youth and 32 age-matched healthy participants (HC) during the performance of a Simon task. General linear modeling was used to compare patterns of brain activation during correct responses to conflict stimuli across groups. Psychophysiological interaction analyses were used to examine conflict-related fronto-striatal connectivity across groups. Associations of fronto-striatal activation and connectivity with cannabis use measures were explored. RESULTS:Reduced conflict-related activity was detected in CU relative to HC youth in fronto-striatal regions, including ventromedial prefrontal cortex (vmPFC), striatum, pallidum and thalamus. Fronto-striatal connectivity did not differ across groups, but negative connectivity between vmPFC and striatum was detected in both groups. CONCLUSION/CONCLUSIONS:These findings are consistent with previous reports of cannabis-associated disturbances in fronto-striatal circuits in adults and point to the specific influence of cannabis on neurodevelopmental changes in youth. Future studies should examine whether fronto-striatal functioning is a reliable marker of CUD severity and potential target for circuit-based interventions.

Attention deficit/hyperactivity disorder (ADHD) is a highly heritable childhood behavioral disorder affecting 5% of children and 2.5% of adults. Common genetic variants contribute substantially to ADHD susceptibility, but no variants have been robustly associated with ADHD. We report a genome-wide association meta-analysis of 20,183 individuals diagnosed with ADHD and 35,191 controls that identifies variants surpassing genome-wide significance in 12 independent loci, finding important new information about the underlying biology of ADHD. Associations are enriched in evolutionarily constrained genomic regions and loss-of-function intolerant genes and around brain-expressed regulatory marks. Analyses of three replication studies: a cohort of individuals diagnosed with ADHD, a self-reported ADHD sample and a meta-analysis of quantitative measures of ADHD symptoms in the population, support these findings while highlighting study-specific differences on genetic overlap with educational attainment. Strong concordance with GWAS of quantitative population measures of ADHD symptoms supports that clinical diagnosis of ADHD is an extreme expression of continuous heritable traits.

AIM/OBJECTIVE:Data pertaining to child and adolescent psychiatry (CAP) training systems are limited as extant research has mostly been derived from one-time data collection. This 5-year follow-up survey collects updated information on CAP training systems in the Far East, allowing for the tracking of system changes over the past 5 years. METHODS:Data were obtained from 18 countries, or functionally self-governing areas, in the Far East, 17 of which were also included in the original study. An online questionnaire was completed by leading CAP professionals in each country. Questions were expanded in the present study to capture the contents of CAP training. RESULTS:When compared to data from the original study, there has been progress in CAP training systems in the last 5 years. Specifically, there has been an increase in the number of countries with CAP training programs and national guidelines for the training. In addition, the number of CAP departments/divisions affiliated with academic institutions/universities has increased. Findings from 12 of 18 countries in the present study provide data on clinical contents. All informants of the present study reported the need for more child and adolescent psychiatrists and allied professionals. CONCLUSION/CONCLUSIONS:Despite progress in CAP training systems over the last 5 years, the need for more professionals in child and adolescent mental health care in all the relevant areas in this region have yet to be adequately addressed. Continued national efforts and international collaborations are imperative to developing and sustaining new CAP training systems while facilitating improvements in existing programs.