Ocular accommodation and cognitive demand: An additional indicator besides pupil size and cardiovascular measures?

<p>Abstract</p> <p>Background</p> <p>The aim of the present study was to assess accommodation as a possible indicator of changes in the autonomic balance caused by altered cognitive demand. Accounting for accommodative responses from a human factors perspective may be motivated by the interest of designing virtual image displays or by establishing an autonomic indicator that allows for remote measurement at the human eye. Heart period, pulse transit time, and the pupillary response were considered as reference for possible closed-loop accommodative effects. Cognitive demand was varied by presenting monocularly numbers at a viewing distance of 5 D (20 cm) which had to be read, added or multiplied; further, letters were presented in a "n-back" task.</p> <p>Results</p> <p>Cardiovascular parameters and pupil size indicated a change in autonomic balance, while error rates and reaction time confirmed the increased cognitive demand during task processing. An observed decrease in accommodation could not be attributed to the cognitive demand itself for two reasons: (1) the cognitive demand induced a shift in gaze direction which, for methodological reasons, accounted for a substantial part of the observed accommodative changes. (2) Remaining effects disappeared when the correctness of task processing was taken into account.</p> <p>Conclusion</p> <p>Although the expectation of accommodation as possible autonomic indicator of cognitive demand was not confirmed, the present results are informative for the field of applied psychophysiology noting that it seems not to be worthwhile to include closed-loop accommodation in future studies. From a human factors perspective, expected changes of accommodation due to cognitive demand are of minor importance for design specifications – of, for example, complex visual displays.</p

Relationship Characteristics Differ Based on Use of Substances with Sex among an Urban Internet Sample of HIV-Discordant and HIV-Positive Male Couples

Previous research with men who have sex with men (MSM) has found that substance use with sex is strongly associated with HIV acquisition and poor adherence to HIV treatments. Although some studies have assessed male couples’ use of substances with unprotected anal sex, little is known on whether differences in their relationship dynamics are associated with their usage. Current HIV prevention initiatives underscore the importance of studying male couples’ relationship dynamics. Using dyadic data from 28 HIV-positive and 58 HIV-discordant male couples, this analysis sought to: (1) describe, by substance type, whether neither, one, or both partners in the couple used a particular substance with sex within their relationship or outside of the relationship, respectively, and (2) assess, by substance type, whether relationship characteristic differences existed between these three groups of couples with respect to substance use with sex within and outside the relationship. Data from 86 dyads came from a cross-sectional, Internet study. Multivariate multinomial regression models were employed to achieve the aims. Except for alcohol, most did not use substances with sex. Within the relationship, those who used with sex varied by substance type; outside the relationship, most couples had only one partner who used with sex regardless of substance type. Several relationship characteristic differences were noted between the groups of couples. Within the relationship, marijuana and erectile dysfunction medication (EDM) use with sex was associated with having less tangible resources; for outside the relationship, these were associated with perceiving to have greater quality of alternatives. In general, amyl nitrates and party drug use with sex were associated with viewing the main partner as being less dependable for trustworthiness. Marijuana and party drug use with sex within the relationship and EDM use with sex outside the relationship were negatively associated with being able to communicate constructively. Mixed results were noted for relationship satisfaction. Additional research is urgently needed for prevention and promotion of healthy relationships for male couples who use substances with sex

Molecular Analysis of Endocrine Disruption in Hornyhead Turbot at Wastewater Outfalls in Southern California Using a Second Generation Multi-Species Microarray

Sentinel fish hornyhead turbot ( Pleuronichthys verticalis ) captured near wastewater outfalls are used for monitoring exposure to industrial and agricultural chemicals of ~ 20 million people living in coastal Southern California. Although analyses of hormones in blood and organ morphology and histology are useful for assessing contaminant exposure, there is a need for quantitative and sensitive molecular measurements, since contaminants of emerging concern are known to produce subtle effects. We developed a second generation multi-species microarray with expanded content and sensitivity to investigate endocrine disruption in turbot captured near wastewater outfalls in San Diego, Orange County and Los Angeles California. Analysis of expression of genes involved in hormone [e.g., estrogen, androgen, thyroid] responses and xenobiotic metabolism in turbot livers was correlated with a series of phenotypic end points. Molecular analyses of turbot livers uncovered altered expression of vitellogenin and zona pellucida protein, indicating exposure to one or more estrogenic chemicals, as well as, alterations in cytochrome P450 (CYP) 1A, CYP3A and glutathione S-transferase-α indicating induction of the detoxification response. Molecular responses indicative of exposure to endocrine disruptors were observed in field-caught hornyhead turbot captured in Southern California demonstrating the utility of molecular methods for monitoring environmental chemicals in wastewater outfalls. Moreover, this approach can be adapted to monitor other sites for contaminants of emerging concern in other fish species for which there are few available gene sequences

A candidate gene study of intermediate histopathological phenotypes in HIV-associated neurocognitive disorders

HIV-associated neurocognitive disorders (HAND) describe a spectrum of neuropsychological impairment caused by HIV-1 infection. While the sequence of cellular and physiological events that lead to HAND remains obscure, it likely involves chronic neuroinflammation. Host genetic markers that increase the risk for HAND have been reported, but replication of such studies is lacking, possibly due to inconsistent application of a behavioral phenotype across studies. In the current study, we used histopathologic phenotypes in order to validate putative risk alleles for HAND. The National NeuroAIDS Tissue Consortium, a longitudinal study of the neurologic manifestations of HIV. Data and specimens were obtained from 175 HIV-infected adults. After determining several potential covariates of neurocognitive functioning, we quantified levels of six histopathological markers in the frontal lobe in association with neurocognitive functioning: SYP, MAP 2, HLA-DR, Iba1, GFAP, and β-amyloid. We then determined alleles of 15 candidate genes for their associations with neurocognitive functioning and histopathological markers. Finally, we identified the most plausible causal pathway based on our data using a multi-stage linear regression-based mediation analysis approach. None of the genetic markers were associated with neurocognitive functioning. Of the histopathological markers, only MAP 2 and SYP were associated with neurocognitive functioning; however, MAP 2 and SYP did not vary as a function of genotype. Mediation analysis suggests a causal pathway in which presynaptic degeneration (SYP) leads to somatodendritic degeneration (MAP 2) and ultimately neurocognitive impairment. This study did not support the role of host genotype in the histopathology underlying HAND. The findings lend further support for synaptodendritic degeneration as the proximal underlying neuropathological substrate of HAND