Altered functional activations of prefrontal brain areas during emotional processing of fear in Inuit adolescents exposed to environmental contaminants.

Exposure to mercury, lead and polychlorinated biphenyls (PCBs) have been associated with emotional dysregulation, but their neuronal correlates have yet to be examined. Inuit from Nunavik (Northern Quebec, Canada) face internalizing problems and are among the most exposed individuals to these environmental contaminants in the world. The aim of this study was to examine the link between pre- and postnatal exposure to these contaminants and brain fear-circuitry in Inuit adolescents. Facial expression stimuli were presented to participants (mean age = 18.3 years) in a magnetic resonance imaging (MRI) scanner. Fear conditioning and extinction tasks included neutral faces as the conditioned threat and safety cues and a fearful face paired with a shrieking scream as the unconditioned stimulus. Functional MRI data were gathered at the conditioning phase (n = 71) and at the extinction phase (n = 62). Mercury, lead and PCB 153 concentrations were measured in blood samples at birth (cord blood) and at the time of the adolescent testing to estimate pre- and postnatal exposure, respectively. For each time point, exposures were categorized in tertiles (low, moderate and high exposed groups). Mixed analyses of variance were conducted for each contaminant of interest controlling for sex, age, socioeconomic status, drug/alcohol use, food insecurity and contaminant co-exposure. Results revealed greater differential activation during the conditioning phase in the right orbitofrontal cortex in participants with moderate and high concentrations of cord blood PCB 153 compared to those in the low exposure group. During the extinction phase, the high prenatal mercury exposed group showed a lower differential activation in the right and left anterior cingulate cortex compared to those in the low-exposed group; whereas there was a higher differential activation in right dorsolateral prefrontal cortex in the high postnatal lead exposed group compared to the moderate- and low-exposed groups. Our study is the first to show alterations in the prefrontal brain areas in fear conditioning and extinction tasks in relation to environmental contaminant exposures. The observed brain correlates may advance our understanding of the emotional problems associated with environmental chemical toxicity.

Risk factors associated with developing anxiety in Inuit adolescents from Nunavik.

This study aimed to examine the relation between anxiety among the at-risk population of Inuit adolescents and diverse developmental risk factors including exposure to environmental chemicals, a subject of concern in Nunavik. Anxiety was assessed in 89 Inuit participants (mean age = 18.4 years; range = 16.2-21.9) with the Screen for Child Anxiety Related Emotional Disorders (SCARED) and the State-Trait Anxiety Inventory (STAI). Potential risk factors for anxiety were documented at birth, 11 years of age and 18 years of age, including blood levels of chemicals (mercury, lead, PCBs) and nutrients, as well as age, sex, estimated IQ, drug and alcohol use, bullying, exposure to domestic violence, food insecurity, crowding and socio-economic status. Results showed that participants scored high on both measures of anxiety, particularly the SCARED, for which the mean score was above the clinical threshold. Multiple regression results show that significant risk predictors obtained from the SCARED scores were female sex (ß = 0.32), higher current blood mercury concentration (ß = 0.26), food insecurity (ß = 0.26) and bullying experiences in the last year (ß = 0.21). The significant predictors for the STAI trait anxiety were food insecurity (ß = 0.25) and lower estimated IQ (ß = -0.31), whereas food insecurity (ß = 0.21), lower blood levels of vitamin E (ß = -0.25) and higher cord blood mercury concentrations (ß = 0.25) were found for STAI situational anxiety. Further regression analyses suggested that the adolescent-related variables were the most important risk factors. Our findings show that Inuit adolescents are at risk for anxiety via multiple contributing factors, particularly current exposure to mercury, food insecurity and female sex.

The conditioning and extinction of fear in youths: what's sex got to do with it?

Adult work shows differences in emotional processing influenced by sexes of both the viewer and expresser of facial expressions. We investigated this in 120 healthy youths (57 boys; 10-17 years old) randomly assigned to fear conditioning and extinction tasks using either neutral male or female faces as the conditioned threat and safety cues, and a fearful face paired with a shrieking scream as the unconditioned stimulus. Fear ratings and skin conductance responses (SCRs) were assessed. Male faces triggered increased fear ratings in all participants during conditioning and extinction. Greater differential SCRs were observed in boys viewing male faces and in girls viewing female faces during conditioning. During extinction, differential SCR findings remained significant in boys viewing male faces. Our findings demonstrate how sex of participant and sex of target interact to shape fear responses in youths, and how the type of measure may lead to distinct profiles of fear responses.

Disturbed dreaming during the third trimester of pregnancy.

OBJECTIVE: The majority of women develop sleep impairments during pregnancy, but alterations in dream experiences remain poorly understood. This study aimed to assess prospectively and comparatively the recall of dreaming and of disturbed dreaming in late pregnancy. METHODS: Fifty-seven nulliparous, third-trimester pregnant women (mean age±SD, 28.7±4.06 years) and 59 non-pregnant controls (mean age±SD, 26.8±4.21 years) completed demographics and psychological questionnaires. A 14-day prospective home log assessed sleep and dream characteristics and the Sleep Disorders Questionnaire measured retrospective dream and disturbed dream recall. RESULTS: Even though pregnant and non-pregnant women showed similar prospective dream recall (P=0.47), pregnant women reported prospectively more bad dreams (P=0.004). More pregnant women (21%) than non-pregnant women (7%) reported a nightmare incidence exceeding moderately severe pathology (>1/week) (P=0.03). Pregnant women also reported overall lower sleep quality (P=0.007) and more night awakenings (P=0.003). Higher prospective recall of bad dreams (r = -0.40, P=0.002) and nightmares (r = -0.32, P=0.001) both correlated with lower sleep quality in pregnant women. CONCLUSIONS: Late pregnancy is a period of markedly increased dysphoric dream imagery that may be a major contributor to impaired sleep at this time. Further polysomnographic assessments of pregnant women are needed to clarify relationships between sleep and disturbed dream production in this population.

Maternal representations in the dreams of pregnant women: a prospective comparative study.

Dreams are thought to respond to self- and socially-relevant situations that evoke strong emotions and require rapid adaptation. First pregnancy is such a situation during which maternal mental representations (MMR) of the unborn baby, the self and significant others undergo remodeling. Some studies suggest that dreams during pregnancy contain more MMR and are more dysphoric, but such studies contain important methodological flaws. We assessed whether dreamed MMR, like waking MMR, change from the 7th month of pregnancy to birth, and whether pregnancy-related themes and non-pregnancy characteristics are also transformed. Sixty non-pregnant and 59 pregnant women (37 early and 22 late 3rd trimester) completed demographic and psychological questionnaires and 14-day home dream logs. Dream reports were blindly rated according to four dream categories: (1) Dreamed MMR, (2) Quality of baby/child representations, (3) Pregnancy-related themes, (4) Non-pregnancy characteristics. Controlling for age, relationship and employment status, education level and state anxiety, women in both pregnant groups reported more dreams depicting themselves as a mother or with babies/children than did non-pregnant women (all p = 0.006). Baby/child representations were less specific in the late 3rd than in the early 3rd trimester (p = 0.005) and than in non-pregnant women (p = 0.01). Pregnant groups also had more pregnancy, childbirth and fetus themes (all p = 0.01). Childbirth content was higher in late than in early 3rd trimester (p = 0.01). Pregnant groups had more morbid elements than did the non-pregnant group (all p < 0.05). Dreaming during pregnancy appears to reflect daytime processes of remodeling MMR of the woman as a mother and of her unborn baby, and parallels a decline in the quality of baby/child representations in the last stage of pregnancy. More frequent morbid content in late pregnancy suggests that the psychological challenges of pregnancy are reflected in a generally more dysphoric emotional tone in dream content.