In vivo imaging in transgenic songbirds reveals superdiffusive neuron migration in the adult brain.

Neuron migration is a key phase of neurogenesis, critical for the assembly and function of neuronal circuits. In songbirds, this process continues throughout life, but how these newborn neurons disperse through the adult brain is unclear. We address this question using in vivo two-photon imaging in transgenic zebra finches that express GFP in young neurons and other cell types. In juvenile and adult birds, migratory cells are present at a high density, travel in all directions, and make frequent course changes. Notably, these dynamic migration patterns are well fit by a superdiffusive model. Simulations reveal that these superdiffusive dynamics are sufficient to disperse new neurons throughout the song nucleus HVC. These results suggest that superdiffusive migration may underlie the formation and maintenance of nuclear brain structures in the postnatal brain and indicate that transgenic songbirds are a useful resource for future studies into the mechanisms of adult neurogenesis.

The effects of dietary fatty acids in the physiological outcomes of maternal high-fat diet on offspring energy homeostasis in mice.

The early-life origins of disease hypothesis has been applied to obesity research and modeled through overnutrition, usually with a high-fat diet (HFD). Since the obesity epidemic coincided with societal change in dietary fat consumption, rather than amount, manipulation of fatty acid (FA) profile is an under-investigated area of study. Additionally, the binding of FAs to nuclear receptors may have persistent intergenerational, extranutritive endocrinological effects that interact with the actions of reproductive steroids causing sex-dependent effects. To determine the role of FA type in the effects underlying maternal HFD, we fed wild-type C57BL6/J mating pairs, from preconception through lactation, a HFD with high saturated fat levels from coconut oil or high linoleic acid (LA) levels from vegetable oil. Male and female offspring body weight and food intake were measured weekly for 25 weeks. Assays for glucose metabolism, body composition, and calorimetry were performed at 25 weeks. Plasma metabolic peptides and liver mRNA were measured terminally. Obesity was primarily affected by adult rather than maternal diet in males, yet in females, maternal HFD potentiated the effects of adult HFD. Maternal HFD high in LA impaired glucose disposal in males weaned onto HFD and insulin sensitivity of females. Plasma leptin correlated with adiposity, but insulin and insulin receptor expression in the liver were altered by maternal LA in males. Our results suggest that maternal FA profile is most influential on offspring glucose metabolism and that adult diet is more important than maternal diet for obesity and other parameters of metabolic syndrome.