Behavior In Healthy Adults Research Articles

The Effect of Multi-Session Prefrontal Cortical Stimulation on Aggression: A Randomized, Double-Blind, Parallel-Group Trial.

Findings from brain imaging studies investigating the neural underpinnings of antisocial behavior have implicated the prefrontal cortex in the regulation of aggressive reactions. However, relatively few studies have examined the role of the prefrontal cortex on aggression in an experimental way. This study examines whether upregulating the prefrontal cortex using repeated transcranial direct current stimulation (tDCS) reduces aggressive behavior. In a double-blind, parallel-group, randomized controlled trial, 88 healthy adults (42 males, 46 females) were assigned to one session of anodal tDCS over the ventromedial prefrontal cortex (n = 47) or sham stimulation (n = 41) per day for three consecutive days and assessed using a behavioral measure of aggression. Levels of aggressive responses post-intervention did not significantly differ between the active and sham stimulation groups. However, a significant interaction effect between the stimulation group and gender was observed, whereby males, but not females, exhibited reduced aggression after prefrontal stimulation. To the authors' knowledge, this is the first study to examine the effect of multi-session prefrontal tDCS on aggressive behavior in healthy adults. Results highlight that there are differences in responsivity to tDCS in modifying aggressive behavior.

Larger left hippocampal presubiculum is associated with lower risk of antisocial behavior in healthy adults with childhood conduct history

Conduct Disorder (CD) is defined as aggressive, antisocial, and rule-breaking behavior during childhood. It is a major risk factor for developing antisocial personality disorder (ASPD) in adulthood. However, nearly half the CDs do not develop ASPD. Identification of reversion factors seems crucial for proper interventions. We identified 40 subjects with childhood history of CD (CC) and 1166 control subjects (HC) from Human Connectome Project. Their psychiatric, emotional, impulsivity, and personality traits were extracted. An emotion recognition task-fMRI analysis was done. We also did subregion analysis of hippocampus and amygdala in 35 CC and 69 demographically matched HCs. CC subjects scored significantly higher in antisocial-related evaluations. No differences in task-fMRI activation of amygdala and hippocampus were observed. CCs had larger subfields of the left hippocampus: presubiculum, CA3, CA4, and dentate gyrus. Further, an interaction model revealed a significant presubiculum volume × group association with antisocial, aggression, and agreeableness scores. Our study shows that healthy young adults with a prior history of CD still exhibit some forms of antisocial-like behavior with larger left hippocampal subfields, including presubiculum that also explains the variability in antisocial behavior. These larger left hippocampal subfield volumes may play a protective role against CD to ASPD conversion.

Relationship Between TSH Levels and Cognition in the Young Adult: An Analysis of the Human Connectome Project Data.

The nature of the relationship between serum thyrotropin (TSH) levels and higher cognitive abilities is unclear, especially within the normal reference range and in the younger population. To assess the relationship between serum TSH levels and mental health and sleep quality parameters (fluid intelligence [Gf], MMSE (Mini-Mental State Examination), depression scores, and, finally, Pittsburgh Sleep Quality Index (PSQI) scores (working memory, processing speed, and executive function) in young adults. This was a retrospective analysis of the data from the Human Connectome Project (HCP). The HCP consortium is seeking to map human brain circuits systematically and identify their relationship to behavior in healthy adults. Included were 391 female and 412 male healthy participants aged 22-35 years at the time of the screening interview. We excluded persons with serum TSH levels outside the reference range (0.4-4.5 mU/L). TSH was transformed logarithmically (log TSH). All the key variables were normalized and then linear regression analysis was performed to assess the relationship between log TSH as a cofactor and Gf as the dependent variable. Finally, a machine learning method, random forest regression, predicted Gf from the dependent variables (including alcohol and tobacco use). The main outcome was normalized Gf (nGf) and Gf scores. Log TSH was a significant co-predictor of nGF in females (β = 0.31(±0.1), P < .01) but not in males. Random forest analysis showed that the model(s) had a better predictive value for females (r = 0.39, mean absolute error [MAE] = 0.81) than males (r = 0.24, MAE = 0.77). Higher serum TSH levels might be associated with higher Gf scores in young women.

Snack Package Size and Variety Differentially Influence Energy Intake and Food Choices in Healthy Adults

BackgroundWhile energy and nutritional content of snacks can contribute to overconsumption, other factors within the modern food environment may also influence the amount and types of snacks consumed. ObjectivesThe aim was to examine whether snack package size and variety influence free-living snacking behavior in healthy adults. The impact of intuitive eating score on snacking behavior was also examined. MethodsThirty adults [age: 23.6 ± 0.8 y; BMI (kg/m2): 22.8 ± 0.5] participated in a randomized crossover-design study. Participants were provided, in randomized order, with the following isocaloric snack exposures to consume for 3 d/exposure—1) CONTROL: highly appealing/appetizing snacks (e.g., dessert snacks, candy, savory snacks, fruits and vegetables, protein snacks); 2) LARGE-PACKAGE: similar snacks as CONTROL but in larger package sizes; and 3) VARIETY: larger variety of snacks. The primary outcomes included the 3-d average ad libitum snack energy, macronutrient content, and food choices for each snack exposure. The secondary outcome was the intuitive eating score and snacking behavior. ResultsLARGE-PACKAGE increased snack intake by 11.9% (1150 ± 81 kcal) compared with CONTROL (1030 ± 71 kcal, P = 0.04), whereas VARIETY snack intake (1030 ± 69 kcal) was no different from CONTROL (P = 1.0). LARGE-PACKAGE increased consumption of desserts compared with CONTROL (P = 0.03) and VARIETY (P = 0.02). Alternately, VARIETY increased consumption of fruits and vegetables compared with LARGE-PACKAGE (P = 0.01) and CONTROL (P = 0.01). Intuitive eating score was not significantly associated with snack intake or snack choice (all, P > 0.05). ConclusionsSnack package size and variety differentially influence energy intake and food choices in healthy adults. This trial was registered atclinicaltrials.gov (NCT03940105).

Physiologically based pharmacokinetic/pharmacodynamic modeling to evaluate the absorption of midazolam rectal gel

ObjectiveWe aimed to 1) develop physiologically based pharmacokinetic/pharmacodynamic (PBPK/PD) models of a novel midazolam rectal gel in healthy adults, 2) assess the contribution of different physiologically relevant factors in rectal absorption, and 3) to provide supports for future clinical studies of midazolam rectal gel. MethodsWe developed the rectal PBPK model after built the intravenous and the oral PBPK model. Then, the physiological progress of rectal route was described in terms of the drug release, the rectal absorption and the particle first-pass elimination. Next, the validated PBPK model was combined with the sigmoid Emax PD model. This PBPK/PD model was used to identify the dose range and the critical parameters to ensure safety sedation. ResultsBased on the simulations, the recommended maximum dose for adults’ sedation was 15 mg. And the retention time of midazolam rectal gel should be longer than 3 h to reach over 80% pharmacokinetics and pharmacodynamics effects. ConclusionWe successfully developed a PBPK/PD model for the midazolam rectal gel, which accurately described the PK/PD behavior in healthy adults and indicated the transit time of rectum was the most sensitive parameter for absorption. This PBPK/PD model would be expected to support the future clinical studies and pediatric application.

Caffeine Consumption and Behavioral Symptoms in Nursing Home Residents: A Cross-Sectional Analysis

ObjectiveAlthough behavioral changes are common in nursing home residents with dementia and caffeine is known to influence behavior in healthy adults, the effects of caffeine on the behavior of persons with dementia has received little attention. In this study we assessed the relationship of caffeine and behavioral symptoms in older persons with dementia.DesignA multicenter sub-cohort study embedded in the Elderly Care Physicians (ECP) training program.SettingDutch nursing homes associated with the ECP training program.ParticipantsA total of 206 individuals with both diabetes and dementia resident in Dutch nursing homes.MeasurementsTrainee ECPs collected data on caffeine consumption, cognition and behavioral symptoms using the NPI-NH, MDS-DRS and AES-C. Data on factors known to influence behavior in persons with dementia (e.g. marital status, kidney function, urinary tract infection and medication) were also collected.ResultsOf the 206 participants, 70% showed behavioral symptoms. An increase in caffeine consumption was associated with a decrease in the presence of behavioral symptoms in the NPI-NH cluster affect and NPI-NH item agitation. Caffeine consumption groups also differed on the presence of disinhibition and depression. In addition, the severity of dementia influenced agitation, anxiety and the clusters affect and psychomotor.ConclusionIn a large group of older persons with dementia resident in nursing homes, a low daily consumption of caffeine was associated with greater behavioral symptoms.

Novel Methodological Considerations Regarding the Use of Visual Analog Scale (VAS) Appetite Questionnaires in Tightly Controlled Feeding Trials

ABSTRACTVisual analog scale (VAS) questionnaires are widely used in nutrition research to assess appetite and subsequent food intake. However, a number of methodological considerations exist. The study aims were to test whether 1) appetite VASs alter subsequent food intake and 2) viewing previous appetite responses influences subsequent responses. Twelve healthy adults (age: 22 ± 3 y; BMI: 22.0 ± 3.1 kg/m2) completed the randomized crossover study. On separate days, participants were provided breakfast preloads and completed appetite VASs every 30 min for 4 h or did not complete the questionnaires. When completing VASs, the participants were shown their previous responses (PR) or were not (No-PR). After 4 h, an ad libitum lunch was provided. Hunger, fullness, desire to eat, and prospective food consumption were not different between PR and No-PR. All data are reported as mean ± SEM. VASs did not affect lunch intake (484 ± 50 kcal) compared with no VASs (500 ± 53 kcal, nonsignificant). Thus, neither past appetite responses nor the use of appetite VASs influenced ingestive behavior in healthy adults. This trial was part of a larger acute, randomized crossover trial registered at clinicaltrials.gov as NCT03154606.

Sensory processing styles and eating behaviors in healthy adults

IntroductionEngagement in unhealthy eating behaviors is a significant risk factor for the development of obesity. These eating behaviors include uncontrolled and mindless eating in response to emotional and sensory cues. This study examines the relationship between sensory processing styles and eating behaviors in typical adults.MethodOne hundred and fifty healthy individuals aged 18–60 completed the Adolescent/Adult Sensory Profile, the Dutch Eating Behaviors Questionnaire, and a rating task of 40 healthy and unhealthy food images.FindingsSensory processing styles characterized by passive self-regulation strategies (low registration and sensory sensitivity) were positively correlated with rates of emotional and external eating behaviors. Sensory seeking was positively correlated with ratings of desirability of healthy food images.ConclusionIndividuals whose sensory processing styles are characterized by passive self-regulation strategies are more likely to engage in unhealthy eating behaviors, including ...

Omega-3 Supplementation and the Neural Correlates of Negative Affect and Impulsivity: A Double-Blind, Randomized, Placebo-Controlled Trial in Midlife Adults.

In clinical trials, omega-3 fatty acid supplementation improves symptoms in psychiatric disorders involving dysregulated mood and impulse control, yet it is unclear whether in healthy adults, omega-3 fatty acid supplementation affects mood, impulse control, and the brain systems supporting these processes. Accordingly, this study tested the hypotheses that eciosapentaenoic (EPA) and docosahexaenoic (DHA) acid supplementation reduces negative affect and impulsive behaviors in healthy adults and that these changes correspond to alterations in corticolimbic and corticostriatal brain systems, which support affective and impulsive processes. Healthy volunteers (N = 272) consuming 300 mg/d or less of EPA and DHA were enrolled in a double-blind, randomized, placebo controlled clinical trial. The participants received either capsules providing 1000 mg of EPA and 400 mg of DHA versus identical appearing soybean oil capsules per day for 18 weeks. Negative affect and impulsivity were measured by questionnaire and ecological momentary assessment, as well as functional alterations in corticolimbic and corticostriatal brain systems evoked by standardized functional magnetic resonance imaging tasks. There were no group by time interactions for any questionnaire or ecological momentary assessment measures of mood and impulsivity. Likewise, no group by time interactions were observed for functional magnetic resonance imaging responses evoked within corticolimbic and corticostriatal systems. In healthy adults with low intake of omega-3 fatty acids, moderate-dose supplementation for 18 weeks did not alter affect or impulsive behaviors nor alter corticolimbic and corticostriatal brain functionality. Trial number NCT00663871.

Sex-specific mediation effect of the right fusiform face area volume on the association between variants in repeat length of AVPR1A RS3 and altruistic behavior in healthy adults.

Microsatellite variants in the arginine vasopressin receptor 1A gene (AVPR1A) RS3 have been associated with normal social behaviors variation and autism spectrum disorders (ASDs) in a sex-specific manner. However, neural mechanisms underlying these associations remain largely unknown. We hypothesized that AVPR1A RS3 variants affect altruistic behavior by modulating the gray matter volume (GMV) of specific brain regions in a sex-specific manner. We investigated 278 young healthy adults using the Dictator Game to assess altruistic behavior. All subjects were genotyped and main effect of AVPR1A RS3 repeat polymorphisms and interaction of genotype-by-sex on the GMV were assessed in a voxel-wise manner. We observed that male subjects with relatively short repeats allocated less money to others and exhibited a significantly smaller GMV in the right fusiform face area (FFA) compared with male long homozygotes. In male subjects, the GMV of the right FFA exhibited a significant positive correlation with altruistic behavior. A mixed mediation and moderation analysis further revealed both a significant mediation effect of the GMV of the right FFA on the association between AVPR1A RS3 repeat polymorphisms and allocation sums and a significant moderation effect of sex (only in males) on the mediation effect. Post hoc analysis showed that the GMV of the right FFA was significantly smaller in male subjects carrying allele 426 than in non-426 carriers. These results suggest that the GMV of the right FFA may be a potential mediator whereby the genetic variants in AVPR1A RS3 affect altruistic behavior in healthy male subjects. Hum Brain Mapp 37:2700-2709, 2016. © 2016 Wiley Periodicals, Inc.

Stress and reward: Long term cortisol exposure predicts the strength of sexual preference

Healthy individuals tend to consume available rewards like food and sex. This tendency is attenuated or amplified in most stress-related psychiatric conditions, so we asked if it depends on endogenous levels of the ‘canonical stress hormone’ cortisol. We unobtrusively quantified how hard healthy heterosexual men would work to consume erotic images of women versus men and also measured their exposure to endogenous cortisol in the prior two months. We used linear models to predict the strength of sexual preference from cortisol level, after accounting for other potential explanations. Heterosexual preference declines with self-reported anhedonia but increases with long term exposure to endogenous cortisol. These results suggest that cortisol may affect reward-related behavior in healthy adults.

Bupropion improves attention but does not affect impulsive behavior in healthy young adults.

Bupropion is an effective abstinence aid for cessation of smoking and possibly other drug use as well. There is evidence that bupropion improves attention and impulse control in certain patient populations, and improvements in these processes could mediate its efficacy as an abstinence aid. In the present study, we tested the effects of acute bupropion on measures of attention and impulsivity in healthy adults with d-amphetamine included as a positive control. Twenty-two nonsmokers (11 women) and 11 smokers (4 women) completed four 4-hr sessions where they received placebo, bupropion (150 or 300 mg), or d-amphetamine (20 mg) in capsules. Ninety minutes after capsule administration, participants were tested on attention with a simple reaction time task (SRT) and on impulsivity with the stop task, a delay and probability discounting task (DPD), and the balloon analogue risk task (BART). Participants also completed mood questionnaires during sessions. Bupropion (150 mg) decreased lapses in attention on the SRT, but did not affect performance on the stop task, DPD, or BART. Amphetamine decreased lapses in attention and speeded sensory motor processing time on the SRT but did not significantly affect responding on the stop task or DPD. On the BART, d-amphetamine tended to decrease risk taking in men but increased risk taking in women. Bupropion (300 mg) and d-amphetamine increased ratings of arousal. These results suggest that bupropion improves attention without affecting impulsive behavior in healthy adults. Improvements in attention may contribute to the effectiveness of bupropion as a pharmacotherapy for smoking.

Fitting Manova Models with Missing Continuous or Ordinal Data Using Reference Priors

We present hierarchical MANOVA models for use with continuous or ordinal data in which missing values are readily handled. Full conditional distributions needed for Gibbs sampling are provided and we present two data analyses demonstrating the types of inferences obtainable from these models. The models are fit to an anthropologic data set for the purposes of estimating the Mahalanobis distance between groups of human males based on skeletal measurements, and a bivariate ordinal MANOVA model is fit to cross-classified data describing drinking behavior in healthy adults.