Practical anatomy classes: An alternative to improve the learning of middle school students.

Anatomy is the branch discipline focused on studying organisms' physical structures and parts. Although technological advances are broadening the anatomy study, the practices of prosection and dissection of human cadavers and animals remain a primary teaching method. Despite the large body of research supporting its benefits, in some countries, cadaveric prosection and dissection of vertebrate animals in secondary education have been banned. In the current study, to prevent a lack of access to anatomical sciences education, the use of plastinated biological specimens was proposed for teaching practical biology in middle and high schools. The study was conducted in the 2014 academic year. Eighty-seven middle school students participated in the experiment. Groups consisted of: (i) theoretical classes only; (ii) theoretical class plus prosection with fresh specimens class; (iii) theoretical class plus expository with plastinated specimens classes. A post-test grade method was used to assess the impact of such tasks on the learning experience of each group. An ANOVA test and multiple regression model were used to analyze the effects of the variables of interest. Our study highlighted that students who underwent the plastination practical class had higher overall performance and a higher mean post-test grade than those in the pure theoretical group. A favorable effect of a positive self-knowledge assessment on the students' performance was found, supporting the self-efficacy model of human behavior. Thus, the current study provides further evidence to support the use of plastinated specimens as an effective teaching method in countries where dissection is not feasible.

Social isolation leads to mild social recognition impairment and losses in brain cellularity.

Chronic social stress is a significant risk factor for several neuropsychiatric disorders, mainly major depressive disorder (MDD). In this way, patients with clinical depression may display many symptoms, including disrupted social behavior and anxiety. However, like many other psychiatric diseases, MDD has a very complex etiology and pathophysiology. Because social isolation is one of the multiple depression-inducing factors in humans, this study aims to understand better the link between social stress and MDD using an animal model based on social isolation after weaning, which is known to produce social stress in mice. We focused on cellular composition and white matter integrity to establish possible links with the abnormal social behavior that rodents isolated after weaning displayed in the three-chamber social approach and recognition tests. We used the isotropic fractionator method to assess brain cellularity, which allows us to robustly estimate the number of oligodendrocytes and neurons in dissected brain regions. In addition, diffusion tensor imaging (DTI) was employed to analyze white matter microstructure. Results have shown that post-weaning social isolation impairs social recognition and reduces the number of neurons and oligodendrocytes in important brain regions involved in social behavior, such as the anterior neocortex and the olfactory bulb. Despite the limitations of animal models of psychological traits, evidence suggests that behavioral impairments observed in patients might have similar biological underpinnings.

Congenital Zika Virus Infection Impairs Corpus Callosum Development.

Congenital Zika syndrome (CZS) is a set of birth defects caused by Zika virus (ZIKV) infection during pregnancy. Microcephaly is its main feature, but other brain abnormalities are found in CZS patients, such as ventriculomegaly, brain calcifications, and dysgenesis of the corpus callosum. Many studies have focused on microcephaly, but it remains unknown how ZIKV infection leads to callosal malformation. To tackle this issue, we infected mouse embryos in utero with a Brazilian ZIKV isolate and found that they were born with a reduction in callosal area and density of callosal neurons. ZIKV infection also causes a density reduction in PH3+ cells, intermediate progenitor cells, and SATB2+ neurons. Moreover, axonal tracing revealed that callosal axons are reduced and misrouted. Also, ZIKV-infected cultures show a reduction in callosal axon length. GFAP labeling showed that an in utero infection compromises glial cells responsible for midline axon guidance. In sum, we showed that ZIKV infection impairs critical steps of corpus callosum formation by disrupting not only neurogenesis, but also axon guidance and growth across the midline.