A subset of women who are exposed to infection during pregnancy have an
increased risk of giving birth to a child who will later be diagnosed with a
neurodevelopmental or neuropsychiatric disorder. Although epidemiology studies
have primarily focused on the association between maternal infection and an
increased risk of offspring schizophrenia (SZ), mounting evidence indicates that
maternal infection may also increase the risk of autism spectrum disorder (ASD).
A number of factors, including genetic susceptibility, the intensity and timing
of the infection, and exposure to additional aversive postnatal events, may
influence the extent to which maternal infection alters fetal brain development
and which disease phenotype (ASD; SZ; other neurodevelopmental disorders) is
expressed. Preclinical animal models provide a test bed to systematically
evaluate the effects of maternal infection on fetal brain development, determine
the relevance to human CNS disorders, and to evaluate novel preventative and
therapeutic strategies. Maternal immune activation (MIA) models in mice, rats,
and nonhuman primates suggest that the maternal immune response is the critical
link between exposure to infection during pregnancy and subsequent changes in
brain and behavioral development of offspring. However, differences in the type,
severity, and timing of prenatal immune challenge paired with inconsistencies in
behavioral phenotyping approaches have hindered the translation of preclinical
results to human studies. Here we highlight the promises and limitations of the
MIA model as a preclinical tool to study prenatal risk factors for ASD, and
suggest specific changes to improve reproducibility and maximize translational
potential.
The long‐term effects of three levels of dissolved oxygen (100, 60 and 36% of air saturation) on channel catfish, Ictalurus punctatus, were evaluated under two feeding regimes—a constant rate of 3% of biomass daily and ad libitum. At ad libitum rates (6‐week duration) average gains of 159, 124, and 65 g per fish were obtained in tanks containing oxygen at 100, 60 and 36% of saturation, respectively. In both experiments food consumption and efficiency were drastically reduced at 36% oxygen saturation. Survival rates were 100% in all groups, thus suggesting that disease and parasite problems were not enhanced by a hypoxic environment. In these studies catfish did not demonstrate a polycythemic response to hypoxic conditions.
Eye-tracking methods measure what humans and other animals visually attend to in the environment. In nonhuman primates, eye tracking can be used to test hypotheses about how primates process social information. This information can further our understanding of primate behavior as well as offer unique translational potential to explore causes of or treatments for altered social processing as seen in people with neurodevelopmental disorders such as autism spectrum disorder and schizophrenia. However, previous methods for collecting eye-tracking data in nonhuman primates required some form of head restraint, which limits the opportunities for research with respect to the number of or kinds of primates that can undergo an eye-tracking study. We developed a novel, noninvasive method for collecting eye tracking data that can be used both in animals that are difficult to restrain without sedation as well as animals that are of different ages and sizes as the box size can be adjusted. Using a transport box modified with a viewing window, we collected eye-tracking data in both New (Callicebus cupreus) and Old World monkeys (Macaca mulatta) across multiple developmental time points. These monkeys had the option to move around the box and avert their eyes from the screen, yet, they demonstrated a natural interest in viewing species-specific imagery with no previous habituation to the eye-tracking paradigm. Provided with opportunistic data from voluntary viewing of stimuli, we found that juveniles viewed stimuli more than other age groups, videos were viewed more than static photo imagery, and that monkeys increased their viewing time when presented with multiple eye tracking sessions. This noninvasive approach opens new opportunities to integrate eye-tracking studies into nonhuman primate research.
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