A novel adipose loss-of-function mutant in Drosophila.

To identify genes required for brain growth, we took an RNAi knockdown reverse genetic approach in Drosophila. One potential candidate isolated from this effort is the anti-lipogenic gene adipose (adp). Adp has an established role in the negative regulation of lipogenesis in the fat body of the fly and adipose tissue in mammals. While fat is key to proper development in general, adp has not been investigated during brain development. Here, we found that RNAi knockdown of adp in neuronal stem cells and neurons results in reduced brain lobe volume and sought to replicate this with a mutant fly. We generated a novel adp mutant that acts as a loss-of-function mutant based on buoyancy assay results. We found that despite a change in fat content in the body overall and a decrease in the number of larger (>5 µm) brain lipid droplets, there was no change in the brain lobe volume of mutant larvae. Overall, our work describes a novel adp mutant that can functionally replace the long-standing adp60 mutant and shows that the adp gene has no obvious involvement in brain growth.

Purkinje cell dopaminergic inputs to astrocytes regulate cerebellar-dependent behavior.

Dopamine has a significant role in motor and cognitive function. The dopaminergic pathways originating from the midbrain have received the most attention; however, the relevance of the cerebellar dopaminergic system is largely undiscovered. Here, we show that the major cerebellar astrocyte type Bergmann glial cells express D1 receptors. Dopamine can be synthesized in Purkinje cells by cytochrome P450 and released in an activity-dependent fashion. We demonstrate that activation of D1 receptors induces membrane depolarization and Ca2+ release from the internal store. These astrocytic activities in turn modify Purkinje cell output by altering its excitatory and inhibitory synaptic input. Lastly, we show that conditional knockout of D1 receptors in Bergmann glial cells results in decreased locomotor activity and impaired social activity. These results contribute to the understanding of the molecular, cellular, and circuit mechanisms underlying dopamine function in the cerebellum, revealing a critical role for the cerebellar dopaminergic system in motor and social behavior.

Effective Use of Student-Created Case Studies as Assessment in an Undergraduate Neuroscience Course.

Case studies and student-led learning activities are both effective active learning methods for increasing student engagement, promoting student learning, and improving student performance. Here, we describe combining these instructional methods to use student-created case studies as assessment for an online neurovirology module in a neuroanatomy and physiology course. First, students learned about neurovirology in a flipped classroom format using free, open-access virology resources. Then, students used iterative writing practices to write an interrupted case study incorporating a patient narrative and primary literature data on the neurovirulent virus of their choice, which was graded as a writing assessment. Finally, students exchanged case studies with their peers, and both taught and completed the case studies as low-stakes assessment. Student performance and evaluations support the efficacy of case studies as assessment, where iterative writing improved student performance, and students reported increased knowledge and confidence in the corresponding learning objectives. Overall, we believe that using student-created case studies as assessment is a valuable, student-led extension of effective case study pedagogy, and has wide applicability to a variety of undergraduate courses.

Recovery of Burrowing Behavior After Spinal Cord Injury in the Larval Sea Lamprey.

AbstractFollowing traumatic spinal cord injury, most mammalian species are unable to achieve substantial neuronal regeneration and often experience loss of locomotor function. In contrast, larval sea lampreys (Petromyzon marinus) spontaneously recover normal swimming behaviors by 10-12 weeks post-injury, which is supported by robust regeneration of spinal axons. While recovery of swimming behavior is well established, the lamprey's ability to recover more complex behaviors, such as burrowing, is unknown. Here we evaluated the lamprey's ability to burrow into a sand substrate over the typical time course of functional recovery (1-11 weeks post-injury). Compared to uninjured control lampreys, which burrow rapidly and completely, spinal-transected animals did not attempt burrowing until 2 weeks post-injury; and they often did not succeed in fully covering their entire body in the sand. Burrowing behavior gradually improved over post-injury time, with most animals burrowing partially or completely by 9-11 weeks post-injury. Burrowing behavior has two components: the initial component that resembles swimming with propagated body undulations and the final component that pulls the tail under the sand. While the duration of the initial component did not differ between control and spinal-transected animals across the entire recovery period, the duration of the final component in spinal-transected animals was significantly longer at all time points measured. These data indicate that, after spinal cord injury, lampreys are able to recover burrowing behaviors, though some deficits persist.