The behavioral interactions between adults and newborns are decisive for the fitness and the survival of offsprings across the animal kingdom. In laboratory mice, while virgin females display caregiving behaviors, virgin males are rather neglectful or aggressive towards pups. Despite the importance of these behavioral variations, the underlying neural mechanisms remain poorly understood. Brain regions encoding these behaviors may exhibit sex-dependent functional differences at baseline. Additionally, these structures might undergo sex-specific plasticity after adults interact with the offspring. Emerging evidence suggests sex-based differences in input connectivity, genetics and receptor expression of the epithalamic Lateral Habenula (LHb). Moreover, LHb neuronal activity is instrumental for adult-newborn interactions. However, whether LHb neuronal function varies between sexes and/or undergoes adaptations following interactions with pups has not been fully investigated. In this study, we used in vivo an...

The beginning of this century has seen some major advances in light microscopy, particularly related to neuroscience. These developments in microscopy, coupled with techniques that make tissues transparent, are enabling microscopes to visualize the cellular architecture of whole tissues in 3D with unprecedented detail.

Transgenic mice provide unprecedented access to manipulate and visualize neural circuits, however, those on a C57BL/6 background develop progressive hearing loss, significantly confounding systems-level and behavioral analysis. While outbreeding can limit hearing loss, it introduces strain variability and complicates the generation of complex genotypes. Here, we propose an approach to preserve hearing by crossing transgenic mice with congenic B6.CAST- Cdh23Ahl+ mice, which maintain low-threshold hearing into adulthood. Widefield and two-photon imaging of the auditory cortex revealed that 2.5-month-old C57BL/6 mice exhibit elevated thresholds to high frequency tones and widespread cortical reorganization, with most neurons responding best to lower frequencies. In contrast, Ahl+ C57BL/6 mice exhibited robust neural responses across tested frequencies and sound levels (4-64 kHz, 30-90 dB SPL) and retained low thresholds into adulthood. Our approach offers a cost-effective solution for generating complex genot...

Growth hormone (GH) is a neuromodulator that binds to receptors in the hippocampus and alters synaptic plasticity. Decline in GH levels is associated with normal ageing, stress and disease, and mechanisms proposed involve the hippocampal circuit plasticity. To see how GH affects the hippocampal neural code, we recorded single neurons in the CA1 region of male Long Evans rats with locally altered GH levels. Rats received injections of adeno-associated viruses into the hippocampus to make the cells overexpress either GH or an antagonizing mutated GH (aGH). Place cells were recorded in both familiar and novel environments to allow the assessment of pattern separation in the neural representations termed remapping. All the animals showed intact and stable place fields in the familiar environment. In the novel environment, aGH transfection increased the average firing rate, peak rate and the information density of the CA1 place fields. The tendency of global remapping increased in the GH animals compared to the...

The adrenal medulla is packed with chromaffin cells, modified postganglionic sympathetic neurons that secrete the catecholamines, epinephrine and norepinephrine, during the fight-or-flight response. Sometimes overlooked, is a population of immune cells that also resides within the gland but whose distribution and function is not clear. Here I examine the location of CD45+ hematopoietic cells in the mouse adrenal medulla and show the majority are F4/80+/Lyz2+ macrophages. These cells are present from early post-natal development and widely distributed. Anatomically they are associated with chromaffin cells, found aligned alongside synapsin-ir neuronal varicosities and juxtaposed to CD31-ir blood vessels. Using Lyz2cre-GCaMP6f mice to quantify calcium signaling in macrophages revealed these cells respond directly and indirectly to a wide variety of neuromodulators, including pre- and post-ganglionic transmitters and systemic hormones. Purinergic agonists, histamine, acetylcholine and bradykinin rapidly and r...

Sarah Caddick is a trained neuroscientist. After completing her postdoctoral fellowship, she decided not to continue her research and instead pursue a career in philanthropy. Now, Caddick serves as the neuroscience adviser to Lord Sainsbury of Turville and the Gatsby Charitable Foundation. Here she discusses what she learned in her transition to a career away from the bench and the ins and outs of what it’s like to work as a neuroscientist in philanthropy.

This is Lesson Four in the Implicit Bias Video Series from BruinX, the research and development unit within the University of California, Los Angeles's Office of Equity, Diversity and Inclusion. This video discusses the differences between explicit and implicit bias.

In addition to sharing research with colleagues, it is important to mentor young scientists and explain the benefits of research with the public. To facilitate these activities, we at Boston College (BC) run the following programs:

Melissa Harrington is the interim associate vice president for research, director of the Delaware Center for Neuroscience Research, and professor of biology at Delaware State University (DSU). In My Advice for Finding Mentors, she shared what qualities to look for in potential mentors and how to begin and maintain mentoring relationships. Here, Harrington details her work environment and research approach at DSU, a Historically Black College and University (HBCU) with approximately 4,500 undergraduate and graduate students.

“There are always new discoveries. It never ends,” says Angela Kim from Harvard Medical School on the most exciting aspect of studying neuroscience. As you prepare for another year of scientific discovery, professional development, and training, revisit Neuronline’s most popular resources from 2017. You’ll find fascinating scientific research, surprising facts about publishing a paper, a behind-the-scenes look at what goes into award-winning research, and more.