M. Catherine DeSoto

Blood levels of mercury are related to diagnosis of autism: a reanalysis of an important data set.

The question of what is leading to the apparent increase in autism is of great importance. Like the link between aspirin and heart attack, even a small effect can have major health implications. If there is any link between autism and mercury, it is absolutely crucial that the first reports of the question are not falsely stating that no link occurs. We have reanalyzed the data set originally reported by Ip et al. in 2004 and have found that the original p value was in error and that a significant relation does exist between the blood levels of mercury and diagnosis of an autism spectrum disorder. Moreover, the hair sample analysis results offer some support for the idea that persons with autism may be less efficient and more variable at eliminating mercury from the blood.

When in Doubt, Do it Both Ways: Brain Evidence of the Simultaneous Activation of Conflicting Motor Responses in a Spatial Stroop Task

Response competition is often considered an important contributor to the delayed reaction to stimuli for which physical and semantic information are in conflict (Stroop effect). Response competition implies that brain areas associated with correct and incorrect responses (e.g., left and right motor cortices) should be simultaneously activated in conflict conditions. However, there is at present little direct evidence of this phenomenon, in part because of the paucity of brain imaging techniques that can independently monitor the time course of activation of adjacent brain areas, such as the motor areas. In the present study, we show that the event-related optical signal (EROS) can provide these types of data. The results confirm the prediction that conflict trials elicit simultaneous activation of both motor cortices, whereas nonconflict trials elicit brain activity only in the contralateral motor cortex. These data support a parallel view of the human information processing system.

Estrogens and relationship jealousy

The relation between sex hormones and responses to partner infidelity was explored in two studies reported here. The first confirmed the standard sex difference in relationship jealousy, that males (n=133) are relatively more distressed by a partner’s sexual infidelity and females (n=159) by a partner’s emotional infidelity. The study also revealed that females using hormone-based birth control (n=61) tended more toward sexual jealousy than did other females, and reported more intense affective responses to partner infidelity (n=77). In study two, 47 females were assessed four times across one month. Patterns of response to partner infidelity did not vary by week of menstrual cycle, but significant relations between salivary estradiol level and jealousy responses were obtained during the time of rising and high fertility risk. The implications, at least for females, are that any evolved psychological, affective, or behavioral dispositions regarding reproduction-related relationships are potentially moderated by estradiol, and that the use of synthetic hormones may disrupt this relation.

Ockham's Razor and autism: The case for developmental neurotoxins contributing to a disease of neurodevelopment

Much professional awareness regarding environmental triggers for ASD has been narrowly focused on a single possible exposure pathway (vaccines). Meanwhile, empirical support for environmental toxins as a broad class has been quietly accumulating. Recent research has shown that persons with ASD have comparatively higher levels of various toxins and are more likely to have reduced detoxifying ability, and, that rates of ASD may be higher in areas with greater pollution. This report documents that within the state with the highest rate of ASD, the rate is higher for schools near EPA Superfund sites, t (332)=3.84, p=.0001. The reasons for the rise in diagnoses likely involve genetically predisposed individuals being exposed to various environmental triggers at higher rates than in past generations.

Memory-driven processing in human medial occipital cortex: An event- related optical signal (EROS) study

Memory-driven processing in medial occipital areas (Area V1 and immediately adjacent structures) was investigated noninvasively using the event-related optical signal (EROS). Subjects viewed two letter stimuli presented in the left and right hemifields, respectively. They then viewed a centrally presented test letter and had to indicate whether this letter was the same as either of the letters presented earlier. The initial EROS response to the test stimulus in medial occipital areas (latency: 50-150 ms) was unilaterally suppressed in the hemisphere previously exposed to the same stimulus. This finding suggests that medial occipital cortex activity is modulated by a rapidly adapting hemispheric-specific pattern recognition mechanism.

Fertility Cycle Patterns in Motives for Sexual Behavior

Three studies examined the relationship between fertility, as indexed by day in cycle or salivary estradiol levels, and reported motives for sexual intercourse. Data from university and community samples in both cross-sectional and repeated-measures designs showed that sex-for-intimacy motives are endorsed significantly less by women who are relatively more fertile or show higher salivary estrogen levels. Sex for enhancement, self-affirmation, and partner approval also declined, although the data were less consistent. The remaining motives (coping and power) showed no consistent patterns across fertility status. Results suggest that sexual motives are rooted partly in womans biology and are discussed in terms of plausible evolutionary mechanisms that might promote female “choosiness” at midcycle.

Estrogen fluctuations, oral contraceptives and borderline personality

Results from three studies suggest fluctuation in estrogen level may influence the expression of borderline personality disorder (BPD) symptoms. In the first study, 226 women were administered the Personality Assessment Inventory, borderline scales (PAI-BOR; L.C. Morey, The Personality Assessment Inventory, Professional Manual, 1991) and a questionnaire that assessed time in menstrual cycle and use of oral contraceptives, that is synthetic estrogens. BPD symptoms were most common in women using oral contraceptives and during times in the menstrual cycle when estrogen level is rising. In Study 2, 52 women were measured four times across one menstrual cycle and provided salivary samples at each test session. The samples were assayed and estrogen levels were obtained. The principle finding was that variation in estrogen levels predicted the presence of BPD symptoms (r=0.4, p<0.01). This relationship remained significant when a general increase in negative affect was statistically controlled. Study 3 employed a pre-post Oral Contraceptive (OC) design with a control group. It was found that for women with high pre-existing levels of BPD, symptoms became significantly worse after starting pill use (F (3,42)=4.7; p<0.01). Research findings that link the serotonin system and estrogen are reviewed and theoretical and practical implications are discussed.

Neuroticism and cortisol: The importance of checking for sex differences

Existent research documents an unclear and contradictory pattern between cortisol and personality variables, especially neuroticism. Specifically, no effect, positive correlations and negative correlations have all been reported to exist between cortisol and neuroticism. The current study tested whether males and females have a fundamentally different relationship between HPA activation and neuroticism and if this might partially account for some of the discrepancy in findings. Saliva samples (n=183) for cortisol were collected three times across a 90min period. Neuroticism was measured via the NEO-FFI. For men, neuroticism was positively correlated with cortisol level (r=.29). For women it was negatively correlated. The negative correlation between neuroticism and cortisol level remained when oral contraceptive use was statistically controlled, and the statistical significance actually increased (partial r=-.20). This suggests a slight suppressor effect, explainable by prior research on correlates of oral contraceptive use. Overall, these findings may offer some explanation for the discrepant results that have been reported in the existing literature regarding neuroticism and cortisol measures.

Predicting female attractiveness: a second look at thinness and waist-to-hip ratio

The idea that a 0.7 WHR is preferred was challenged by Puhl and Boland (2001). Their study found that a model with a 0.86 WHR was rated as more attractive than a model with a 0.7 WHR. This study examined the stimuli used by Puhl and Boland for the extent to which the photographs used portray the actual true shape differential of the models.

Synthetic folic acid supplementation during pregnancy may increase the risk of developing autism

Persons in developed countries are getting large amounts of folates in the form of folic acid. Folates are now ingested in three ways: as natural folates from food, as synthetic folic acid added to processed grains, and synthetic vitamin supplements. As a result of the supplementation, the circulating level of unmetabolized folic acid as well as total folates has greatly increased over the past generation, probably to levels largely unprecedented in human history. Folic acid has been shown to be able to epigenetically alter the functioning of the genome and to have long term effects on gene expression. The Centers for Disease Control Vaccine Safety Datalink data set compared children with autism to control children on several variables. Here, we report that folic acid supplementation during gestation is associated with an increased risk for autism. The effect remains even when health seeking behaviors and other variables are controlled.