Sex and pubertal status influence dendritic spine density onto frontal cortiocostriatal projection neurons
In humans, nonhuman primates, and rodents, the frontal cortices exhibit grey matter thinning and dendritic spine pruning that extends late into adolescence. This protracted maturation is believed to support higher cognition but may also confer psychiatric vulnerability during adolescence. Currently, little is known about how different cell types in the frontal cortex mature or whether puberty plays a role. Here, we used mice to characterize the spatial topography and adolescent development of cross-corticostriatal (cSTR) neurons that project to the dorsomedial striatum (DMS). We found that apical spine density on cSTR neurons in the medial prefrontal cortex decreased significantly between late juvenile (P29) and young adult time points (P60), with females exhibiting higher spine density than males at both ages. Adult [...]
Multiple neurocognitive systems contribute simultaneously to learning. For example, dopamine and basal ganglia (BG) systems are thought to support reinforcement learning (RL) by incrementally updating the value of choices, while the prefrontal cortex (PFC) contributes different computations, such as actively maintaining precise information in working memory (WM). It is commonly thought that WM and PFC show more protracted development than RL and BG systems, yet their contributions are rarely assessed in tandem. Here, we used a simple learning task to test how RL and WM contribute to changes in learning across adolescence. We tested 187 subjects ages 8 to 17 and 53 adults (25-30). Participants learned stimulus-action associations from feedback; the learning load was varied to be within or exceed [...]
Variation in early life maternal care predicts later long range frontal cortex synapse development in mice
Empirical and theoretical work suggests that early postnatal experience may inform later developing synaptic connectivity to adapt the brain to its environment. We hypothesized that early maternal experience may program the development of synaptic density on long range frontal cortex projections. To test this idea, we used maternal separation (MS) to generate environmental variability and examined how MS affected 1) maternal care and 2) synapse density on virally-labeled long range axons of offspring reared in MS or control conditions. We found that MS and variation in maternal care predicted bouton density on dorsal frontal cortex axons that terminated in the basolateral amygdala (BLA) and dorsomedial striatum (DMS) with more, fragmented care associated with higher density. The effects of maternal care [...]
Linda Wilbrecht reviews Wildhood: The Epic Journey from Adolescence to Adulthood in Humans and Other Animals by Barbara Natterson-Horowitz and Kathryn Bowers (Scribner, 2019) in Science Magazine. An enduring story plot finds a youth suddenly alone in the world, struggling to find shelter from the elements, safety from predators, food, and new friends. These struggles usually involve some tough lessons but ultimately lead to knowledge, a new identity, self-reliance, and maybe even love. In Wildhood, this theme comes to exhilarating life as evolutionary biologist Barbara Natterson-Horowitz and science writer Kathryn Bowers describe the challenges faced by adolescent animals. Linda Wilbrecht, Coming of Age in the Animal Kingdom, reviewing Barbara Natterson-Horowitz and Kathryn Bowers, Wildhood: The Epic Journey from Adolescence [...]
The Tourette Association of America has awarded its Young Investigator Award to Kristen Delevich for her research project, Studying the Influence of Hormones on the Brain. This work seeks to understand the influence of puberty on brain circuits involved in behavioral control, in an effort to elucidate why Tourette symptoms typically change during adolescence. Congratulations, Dr. Delevich!
We just published our first collaborative paper with the Landry lab in Science Advances. Beyene et al. shows that new nIRCats enable detection of dopamine release with high spatial resolution and are compatible with dopamine receptor pharmacology. There is brief coverage in Nature and a link to the paper is here.