Moderate prenatal alcohol exposure increases total length of L1-expressing axons in E15.5 mice.

Public health campaigns broadcast the link between heavy alcohol consumption during pregnancy and physical, cognitive, and behavioral birth defects; however, they appear less effective in deterring moderate consumption prevalent in women who are pregnant or of childbearing age. The incidence of mild Fetal Alcohol Spectrum Disorders (FASD) is likely underestimated because the affected individuals lack physical signs such as retarded growth and facial dysmorphology and cognitive/behavioral deficits are not commonly detected until late childhood. Sensory information processing is distorted in FASD, but alcohol's effects on the development of axons that mediate these functions are not widely investigated. We hypothesize that alcohol exposure alters axon growth and guidance contributing to the aberrant connectivity that is a hallmark of FASD. To test this, we administered alcohol to pregnant dams from embryonic day (E) 7.5 to 14.5, during the time that axons which form the major forebrain tracts are growing. We found that moderate alcohol exposure had no effect on body weight of E15.5 embryos, but significantly increased the length of L1+ axons. To investigate a possible cause of increased L1+ axon length, we investigated the number and distribution of corridor cells, one of multiple guidance cues for thalamocortical axons which are involved in sensory processing. Alcohol did not affect corridor cell number or distribution at the time when thalamocortical axons are migrating. Future studies will investigate the function of other guidance cues for thalamocortical axons, as well as lasting consequences of axon misguidance with prenatal alcohol exposure.

A Cocurricular Program That Encourages Specific Study Skills and Habits Improves Academic Performance and Retention of First-Year Undergraduates in Introductory Biology.

Students must master content for success in science, technology, engineering, and mathematics (STEM), but "how to" is rarely taught in college. Faculty are reluctant to sacrifice class time, believe such instruction is remedial, or assume students possess or will attain these skills independently. To determine whether explicit instruction would improve skills and performance by first-year undergraduates likely to major in STEM, we invited all students in an introductory biology course to participate in an 8-week Co-Curricular (CoC) program. Students who participated improved time management, used more methods to plan and organize their study, and used a variety of active-learning strategies. A validated model was used to predict students' probability of achieving a "C+" or better in the course. The model, based on 5 years of data, used students' demographic characteristics and previous academic performance to provide a measure of their preparedness. Students with low and medium preparedness who participated in CoC performed better than those who did not participate. All students who participated were retained in the course compared with 88.7% of students who did not participate. Specific behavioral changes at the start of STEM gateway courses can dramatically improve student metacognition, retention, and academic performance, particularly for students underrepresented in the discipline.

White matter abnormalities in fetal alcohol spectrum disorders: Focus on axon growth and guidance.

Fetal Alcohol Spectrum Disorders (FASDs) describe a range of deficits, affecting physical, mental, cognitive, and behavioral function, arising from prenatal alcohol exposure. FASD causes widespread white matter abnormalities, with significant alterations of tracts in the cerebral cortex, cerebellum, and hippocampus. These brain regions present with white-matter volume reductions, particularly at the midline. Neural pathways herein are guided primarily by three guidance cue families: Semaphorin/Neuropilin, Netrin/DCC, and Slit/Robo. These guidance cue/receptor pairs attract and repulse axons and ensure that they reach the proper target to make functional connections. In several cases, these signals cooperate with each other and/or additional molecular partners. Effects of alcohol on guidance cue mechanisms and their associated effectors include inhibition of growth cone response to repellant cues as well as changes in gene expression. Relevant to the corpus callosum, specifically, developmental alcohol exposure alters GABAergic and glutamatergic cell populations and glial cells that serve as guidepost cells for callosal axons. In many cases, deficits seen in FASD mirror aberrancies in guidance cue/receptor signaling. We present evidence for the need for further study on how prenatal alcohol exposure affects the formation of neural connections which may underlie disrupted functional connectivity in FASD.

A Discussion of Diversity and Inclusivity at the Institutional Level: The Need for a Strategic Plan.

A wider discussion is taking place nationally regarding how universities can make 'real' change in the old way of academic business. These changes include a hard look at the inclusive nature of the institutional environment as a whole. Lack of diversity is most noticeable within higher administrative levels of universities across the country. We have now reached a point where true reflection and assessment of inclusive practices on our campuses must be carried out so that we fully serve the needs of all of our students. In this breakout session participants will share best practices currently in place or strategic planning at your institutions, which not only promote diversity and inclusion in the classroom but describe strategies for institutional buy-in at all levels and provide examples of accountability measures that further promote diversity and inclusion at higher administrative levels.

Using Swiss Webster mice to model Fetal Alcohol Spectrum Disorders (FASD): An analysis of multilevel time-to-event data through mixed-effects Cox proportional hazards models.

Fetal Alcohol Spectrum Disorders (FASD) collectively describes the constellation of effects resulting from human alcohol consumption during pregnancy. Even with public awareness, the incidence of FASD is estimated to be upwards of 5% in the general population and is becoming a global health problem. The physical, cognitive, and behavioral impairments of FASD are recapitulated in animal models. Recently rodent models utilizing voluntary drinking paradigms have been developed that accurately reflect moderate consumption, which makes up the majority of FASD cases. The range in severity of FASD characteristics reflects the frequency, dose, developmental timing, and individual susceptibility to alcohol exposure. As most rodent models of FASD use C57BL/6 mice, there is a need to expand the stocks of mice studied in order to more fully understand the complex neurobiology of this disorder. To that end, we allowed pregnant Swiss Webster mice to voluntarily drink ethanol via the drinking in the dark (DID) paradigm throughout their gestation period. Ethanol exposure did not alter gestational outcomes as determined by no significant differences in maternal weight gain, maternal liquid consumption, litter size, or pup weight at birth or weaning. Despite seemingly normal gestation, ethanol-exposed offspring exhibit significantly altered timing to achieve developmental milestones (surface righting, cliff aversion, and open field traversal), as analyzed through mixed-effects Cox proportional hazards models. These results confirm Swiss Webster mice as a viable option to study the incidence and causes of ethanol-induced neurobehavioral alterations during development. Future studies in our laboratory will investigate the brain regions and molecules responsible for these behavioral changes.

Effects of binge ethanol exposure during first-trimester equivalent on corticothalamic neurons in Swiss Webster outbred mice.

Fetal alcohol spectrum disorders range in severity depending on the amount, timing, and frequency of alcohol exposure. Regardless of severity, sensorimotor defects are commonly reported. Sensorimotor information travels through three tracts of the internal capsule: thalamocortical axons, corticothalamic axons, and corticospinal axons. Here we describe the effects of binge ethanol exposure during the first-trimester equivalent on corticothalamic neurons using Swiss Webster mice. We injected pregnant mice with ethanol (2.9 g/kg, intraperitoneal, followed by 1.45 g/kg, intraperitoneal, 2 h later) on embryonic days (E) 11.5, 12.5, and 13.5. Our paradigm resulted in a mean maternal blood ethanol content of 294.8±15.4 mg/dl on E12.5 and 258.3±22.2 mg/dl on E13.5. Control dams were injected with an equivalent volume of PBS. Bromodeoxyuridine birthdating was carried out on E11.5 to label S-phase neurons. The days of injection were chosen because they are at the onset of neurogenesis and axon extension for corticothalamic, thalamocortical, and corticospinal neurons. Ethanol-exposed pups exhibited no differences compared with controls on day of birth in litter size, body weight, or brain weight. Corticothalamic neurons labeled with bromodeoxyuridine and T-box brain 1 were located in the deep layers of the cortex and did not differ in number in both groups. These results contrast several studies demonstrating alcohol-related differences in these parameters using chronic ethanol exposure paradigms and inbred mouse strains. Therefore, our findings highlight the importance of expanding the mouse strains used to model fetal alcohol spectrum disorder to enhance our understanding of its complex etiology.

Mutation of the BiP/GRP78 gene causes axon outgrowth and fasciculation defects in the thalamocortical connections of the mammalian forebrain.

Proper development of axonal connections is essential for brain function. A forward genetic screen for mice with defects in thalamocortical development previously isolated a mutant called baffled. Here we describe the axonal defects of baffled in further detail and identify a point mutation in the Hspa5 gene, encoding the endoplasmic reticulum chaperone BiP/GRP78. This hypomorphic mutation of BiP disrupts proper development of the thalamocortical axon projection and other forebrain axon tracts, as well as cortical lamination. In baffled mutant brains, a reduced number of thalamic axons innervate the cortex by the time of birth. Thalamocortical and corticothalamic axons are delayed, overfasciculated, and disorganized along their pathway through the ventral telencephalon. Furthermore, dissociated mutant neurons show reduced axon extension in vitro. Together, these findings demonstrate a sensitive requirement for the endoplasmic reticulum chaperone BiP/GRP78 during axon outgrowth and pathfinding in the developing mammalian brain.

A forward genetic screen with a thalamocortical axon reporter mouse yields novel neurodevelopment mutants and a distinct emx2 mutant phenotype.

BACKGROUND: The dorsal thalamus acts as a gateway and modulator for information going to and from the cerebral cortex. This activity requires the formation of reciprocal topographic axon connections between thalamus and cortex. The axons grow along a complex multistep pathway, making sharp turns, crossing expression boundaries, and encountering intermediate targets. However, the cellular and molecular components mediating these steps remain poorly understood. RESULTS: To further elucidate the development of the thalamocortical system, we first created a thalamocortical axon reporter line to use as a genetic tool for sensitive analysis of mutant mouse phenotypes. The TCA-tau-lacZ reporter mouse shows specific, robust, and reproducible labeling of thalamocortical axons (TCAs), but not the overlapping corticothalamic axons, during development. Moreover, it readily reveals TCA pathfinding abnormalities in known cortical mutants such as reeler. Next, we performed an unbiased screen for genes involved in thalamocortical development using random mutagenesis with the TCA reporter. Six independent mutant lines show aberrant TCA phenotypes at different steps of the pathway. These include ventral misrouting, overfasciculation, stalling at the corticostriatal boundary, and invasion of ectopic cortical cell clusters. An outcross breeding strategy coupled with a genomic panel of single nucleotide polymorphisms facilitated genetic mapping with small numbers of mutant mice. We mapped a ventral misrouting mutant to the Emx2 gene, and discovered that some TCAs extend to the olfactory bulbs in this mutant. Mapping data suggest that other lines carry mutations in genes not previously known for roles in thalamocortical development. CONCLUSIONS: These data demonstrate the feasibility of a forward genetic approach to understanding mammalian brain morphogenesis and wiring. A robust axonal reporter enabled sensitive analysis of a specific axon tract inside the mouse brain, identifying mutant phenotypes at multiple steps of the pathway, and revealing a new aspect of the Emx2 mutant. The phenotypes highlight vulnerable choice points and latent tendencies of TCAs, and will lead to a refined understanding of the elements and interactions required to form the thalamocortical system.

A pharmacological activator of AMP-activated protein kinase (AMPK) induces astrocyte stellation.

AMP-activated protein kinase (AMPK) represents a key energy-sensing molecule in many cell types. Because astrocytes are key mediators of metabolic signaling in the brain, we have initiated studies on the expression and activation of AMPK in these cells. Treatment of cultured rat cortical astrocytes with a pharmacological AMPK activator, AICA-riboside (AICAR) resulted in a time- and concentration-dependent increase in phosphorylation of AMPK and acetyl-CoA carboxylase (ACC), a direct substrate. AICAR treatment also induced a transition from epithelioid to stellate morphology in a time- and concentration-dependent manner. As stellation is indicative of actin cytoskeletal reorganization, the formation of stress fibers and focal adhesions in response to AICAR was assessed. AICAR-induced stellation correlated with F-actin disassembly and focal adhesion dispersal. Furthermore, transient transfection of an activated RhoA construct prevented AICAR-induced stellation, indicating a mechanism upstream of RhoA. Use of pharmacological inhibitor compound C prevented AICAR-induced stellation demonstrating necessity of AMPK activity for the response. Our findings suggest that AMPK mediates morphological alterations of astrocytes in response to energy depletion.