A Double Dissociation Between Inattentive and Impulsive Traits, on Tasks of Visual Processing and Emotion Regulation

Attention to faces in images is associated with personality and psychopathology

Humans show a robust tendency to look at faces in images, but also differ consistently in the strength of this attentional preference. Previous research remained inconclusive as to how a stronger face preference may be indicative of an individual's personality or clinical characteristics. Here we investigated face preferences in 120 participants (primarily drawn from a student population) who freely viewed photos in an internet browser showing a person in the context of a visually rich environment while attention was assessed using a cursor-based technique. Participants differed consistently in the strength of their face preference across images. A stronger preference for faces was correlated positively with openness to experience, extraversion, agreeableness and empathizing and was correlated negatively with social anxiety, depression levels and alexithymia. Trait measures were linked through a strong common factor which was additionally correlated with face preference. We conclude that face preferences may be linked to personality traits and to psychopathology but that an attribution to a specific facet of psychopathology may not be warranted. Future research should investigate links between face preferences and personality features in more diverse samples and across differing social situations.

The effects of sleep deprivation on the processing of emotional facial expressions in young adults with and without ADHD

The ability to recognize emotions from facial expressions is essential to the development of complex social cognition behaviors, and impairments in this ability are associated with poor social competence. This study aimed to examine the effects of sleep deprivation on the processing of emotional facial expressions and nonfacial stimuli in young adults with and without attention-deficit/hyperactivity disorder (ADHD). Thirty-five men (mean age 25.4) with (n = 19) and without (n = 16) ADHD participated in the study. During the five days preceding the experimental session, the participants were required to sleep at least seven hours per night (23:00/24:00–7:00/9:00) and their sleep was monitored via actigraphy. On the morning of the experimental session, the participants completed a 4-stimulus visual oddball task combining facial and nonfacial stimuli, and repeated it after 25 h of sustained wakefulness. At baseline, both study groups had poorer performance in response to facial rather than non-facial target stimuli on all indices of the oddball task, with no differences between the groups. Following sleep deprivation, rates of omission errors, commission errors and reaction time variability increased significantly in the ADHD group but not in the control group. Time and target type (face/non-face) did not have an interactive effect on any indices of the oddball task. Young adults with ADHD are more sensitive to the negative effects of sleep deprivation on attentional processes, including those related to the processing of emotional facial expressions. As poor sleep and excessive daytime sleepiness are common in individuals with ADHD, it is feasible that poor sleep quality and quantity play an important role in cognitive functioning deficits, including the processing of emotional facial expressions that are associated with ADHD.

The Sleepiness Curve of Young Men With and Without Attention-Deficit Hyperactivity Disorder (ADHD)

Objectives: The present study aimed at comparing the sleepiness curve of young men with attention-deficit hyperactivity disorder (ADHD) to that of young men without ADHD before, during, and after a night of sleep deprivation. Participants: Thirty young men (age 18-30) of whom 14 were diagnosed with ADHD combined type (ADHD-C) and 16 without ADHD. Methods: The participants' sleep was monitored for 5 days via actigraphy. Subsequently, the participants were kept continuously awake in a controlled environment for 25 hr (8:00 a.m.-9:00 a.m.). The sleepiness of the participants was assessed every hour by the Karolinska Sleepiness Scale (KSS) in order to obtain the sleepiness curve of both study groups. Results: Actigraphy data demonstrated that the two groups did not differ in their total sleep time, sleep onset latency, or sleep efficiency during the 5 nights preceding the experimental session. However, during the experimental session, the ADHD group demonstrated higher sleepiness scores, particularly following midnight and on the morning following the night of sleep deprivation. Moreover, on the morning following sleep deprivation the proportion of participants reporting extreme levels of sleepiness (KSS > 7) was significantly higher in the ADHD group than in the control group. Conclusions: Young men with ADHD suffer from sleepiness more than their counterparts from the general population, and are particularly vulnerable to the effects of sleep deprivation on sleepiness. As excessive daytime sleepiness negatively affects cognition and increases the risk for motor vehicle crash and other accidents, these findings may have important clinical implications.

Accessing Gene Expression in Treatment-Resistant Schizophrenia

Schizophrenia (SCZ) is a mental disorder arising from a complex interaction of genetic and environmental factors. It has been suggested that treatment-resistant schizophrenia (TRS) is a distinct, more severe, and homogenous subgroup of schizophrenia that could present specific biological markers. Our aim was to characterize expression of target genes in blood of TRS patients compared with non-TRS (NTRS) patients and healthy controls (HC). TRS has been defined using failure to respond to two previous antipsychotic trials. We hypothesized that genes involved in neurodevelopment, myelination, neuroplasticity, neurotransmission, and miRNA processing could be involved in treatment resistance; then, we investigated 13 genes related to those processes in 256 subjects, being 94 healthy controls and 162 schizophrenia patients treated with antipsychotics. Of those, 78 were TRS patients and 84 were NTRS patients. Peripheral blood samples were collected from all subjects and RNA was isolated. Gene expression analysis was performed using the TaqMan low-density array (TLDA) technology. To verify the influence of expression quantitative trait loci (eQTLs), we evaluated single-nucleotide polymorphism (SNP) of all genes using data from GTEx Project. SNP genotypes were obtained from HumanOmniExpress BeadChip. We did not detect gene expression differences between TRS and NTRS subjects, indicating candidate genes specific to treatment resistance. We detected an upregulation of CNR1 and UFD1L gene expression in patients (TRS and NTRS groups) when compared to controls, that may be associated with the release of neurotransmitters, which can influence neuronal plasticity, or with a stress response-activating protein degradation. DICER1 and AKT1 expression increased slightly across the groups and could differentiate only the extreme opposite groups, HC and TRS. Both genes act in heterogeneous pathways, such as cell signaling and miRNA processing, and seem to have an increased demand in the TRS group. We did not detect any eQTLs in our sample that could explain differences in mRNA levels, suggesting a possible regulation by other mechanism, not driven by genotypes. Our data strengthen the importance of several biological pathways involved in the schizophrenia refractoriness and severity, adding knowledge to develop more effective treatments in the future.

Dissociable deficits of executive function caused by gestational adversity are linked to specific transcriptional changes in the prefrontal cortex

Poor-quality maternal diet during pregnancy, and subsequent gestational growth disturbances in the offspring, have been implicated in the etiology of multiple neurodevelopmental disorders, including ADHD, schizophrenia, and autism. These disorders are characterized, in part, by abnormalities in responses to reward and errors of executive function. Here, we demonstrate dissociable deficits in reward processing and executive function in male and female mice, solely due to maternal malnutrition via high-fat or low-protein diets. Gestational exposure to a high-fat diet delayed acquisition of a fixed ratio response, and decreased motivation as assessed by progressive ratio. In contrast, offspring of a low-protein diet displayed no deficits in operant learning, but were more prone to assign salience to a cue that predicts reward (sign-tracking) in a Pavlovian-conditioned approach task. In the 5-choice serial reaction time task (5-CSRTT), gestational exposure to a high-fat diet promoted impulsivity, whereas exposure to a low-protein diet led to marked inattention. These dissociable executive function deficits are known to be mediated by the medial prefrontal cortex (PFC), which displays markers of epigenetic dysregulation in neurodevelopmental disorders. Following behavioral characterization, we assayed PFC gene expression using a targeted PCR array and found that both maternal diets increased overall transcription in PFC. Cluster analysis of the relationships between individual transcripts and behavioral outcomes revealed a cluster of primarily epigenetic modulators, whose overexpression was linked to executive function deficits. The overexpression of four genes, DNA methyltransferase 1 (DNMT1), δ-opioid receptor (OPRD1), cannabinoid receptor 1 (CNR1), and catechol-o-methyltransferase (COMT), was strongly associated with overall poor performance. All 5-CSRTT deficits were associated with DNMT1 upregulation, whereas impulsive behavior could be dissociated from inattention by overexpression of OPRD1 or COMT, respectively, as well as a distinct cluster of epigenetic regulators. These data provide molecular support for dissociable domains of executive function.