Salivary Cortisol Mediates Effects of Poverty and Parenting on Executive Functions in Early Childhood

In a predominantly low-income population-based longitudinal sample of 1,292 children followed from birth, higher level of salivary cortisol assessed at ages 7, 15, and 24 months was uniquely associated with lower executive function ability and to a lesser extent IQ at age 3 years. Measures of positive and negative aspects of parenting and household risk were also uniquely related to both executive functions and IQ. The effect of positive parenting on executive functions was partially mediated through cortisol. Typical or resting level of cortisol was increased in African American relative to White participants. In combination with positive and negative parenting and household risk, cortisol mediated effects of African American ethnicity, income-to-need, and maternal education on child cognitive ability.

Assessing genetic polymorphisms using DNA extracted from cells present in saliva samples

<p>Abstract</p> <p>Background</p> <p>Technical advances following the Human Genome Project revealed that high-quality and -quantity DNA may be obtained from whole saliva samples. However, usability of previously collected samples and the effects of environmental conditions on the samples during collection have not been assessed in detail. In five studies we document the effects of sample volume, handling and storage conditions, type of collection device, and oral sampling location, on quantity, quality, and genetic assessment of DNA extracted from cells present in saliva.</p> <p>Methods</p> <p>Saliva samples were collected from ten adults in each study. Saliva volumes from .10-1.0 ml, different saliva collection devices, sampling locations in the mouth, room temperature storage, and multiple freeze-thaw cycles were tested. One representative single nucleotide polymorphism (SNP) in the catechol-<it>0</it>-methyltransferase gene (COMT rs4680) and one representative variable number of tandem repeats (VNTR) in the serotonin transporter gene (5-HTTLPR: serotonin transporter linked polymorphic region) were selected for genetic analyses.</p> <p>Results</p> <p>The smallest tested whole saliva volume of .10 ml yielded, on average, 1.43 ± .77 μg DNA and gave accurate genotype calls in both genetic analyses. The usage of collection devices reduced the amount of DNA extracted from the saliva filtrates compared to the whole saliva sample, as 54-92% of the DNA was retained on the device. An "adhered cell" extraction enabled recovery of this DNA and provided good quality and quantity DNA. The DNA from both the saliva filtrates and the adhered cell recovery provided accurate genotype calls. The effects of storage at room temperature (up to 5 days), repeated freeze-thaw cycles (up to 6 cycles), and oral sampling location on DNA extraction and on genetic analysis from saliva were negligible.</p> <p>Conclusions</p> <p>Whole saliva samples with volumes of at least .10 ml were sufficient to extract good quality and quantity DNA. Using 10 ng of DNA per genotyping reaction, the obtained samples can be used for more than one hundred candidate gene assays. When saliva is collected with an absorbent device, most of the nucleic acid content remains in the device, therefore it is advisable to collect the device separately for later genetic analyses.</p

Aggression as an equifinal outcome of distinct neurocognitive and neuroaffective processes

AbstractEarly onset aggression precipitates a cascade of risk factors, increasing the probability of a range of externalizing and internalizing psychopathological outcomes. Unfortunately, decades of research on the etiological contributions to the manifestation of aggression have failed to yield identification of any risk factors determined to be either necessary or sufficient, likely attributable to etiological heterogeneity within the construct of aggression. Differential pathways of etiological risk are not easily discerned at the behavioral or self-report level, particularly in young children, requiring multilevel analysis of risk pathways. This study focuses on three domains of risk to examine the heterogeneity in 207 urban kindergarten children with high levels of aggression: cognitive processing, socioemotional competence and emotion processing, and family context. The results indicate that 90% of children in the high aggression group could be characterized as either low in verbal ability or high in physiological arousal (resting skin conductance). Children characterized as low verbal, high arousal, or both differed in social and emotional competence, physiological reactivity to emotion, and aspects of family-based contextual risk. The implications of this etiologic heterogeneity of aggression are discussed in terms of assessment and treatment.</jats:p

Salivary Cortisol Mediates Effects of Poverty and Parenting on Executive Functions in Early Childhood

In a predominantly low-income population-based longitudinal sample of 1,292 children followed from birth, higher level of salivary cortisol assessed at ages 7, 15, and 24 months was uniquely associated with lower executive function ability and to a lesser extent IQ at age 3 years. Measures of positive and negative aspects of parenting and household risk were also uniquely related to both executive functions and IQ. The effect of positive parenting on executive functions was partially mediated through cortisol. Typical or resting level of cortisol was increased in African American relative to White participants. In combination with positive and negative parenting and household risk, cortisol mediated effects of income-to-need, maternal education, and African American ethnicity on child cognitive ability