Updated April 1st, 2025
Research Spotlight
Growth hormone is crucial for development and growth in childhood, but does it also help adults to keep their brains young and ready to learn? By studying single hippocampal neurons that create a mental map (place cells), Haugland and colleagues saw that rats with high levels of growth hormone responded with more change in their neural representation when the environment was altered. Rats with impaired growth hormone sensitivity had a more rigid mental representation that responded less to changes in the physical environment. The findings may help us understand cognitive changes that happen in ageing.
It was previously shown that TrkB dependent processes acutely after spinal cord injury (SCI) contributes to enhanced pain responses. Jang and Garraway investigated the role of TrkB signaling pain after SCI by examining the effect of systemic TrkB inhibition on agonist-induced inward currents, firing and membrane properties of small sensory neurons known as nociceptors obtained from uninjured and SCI mice. The results revealed that SCI increased neuronal excitability, while decreasing TrkB-induced inward current. Collectively, they suggest that pain hypersensitivity after SCI might be minimally influenced by TrkB signaling in small DRG neurons.
How stress impacts behavioral outcomes of traumatic brain injury (TBI) represents a major gap in knowledge. This oversight is especially felt by those in the military due to the high prevalence of TBI and the abundance of stress that they endure. In a study funded by the US Department of Defense, researchers led by Pamela VandeVord at Virginia Tech discovered that prior stress exposure influences TBI outcomes in a sex-dependent manner. VandeVord and colleagues used an unpredictable stress paradigm on rats prior to causing TBI using a protocol that mimics brain injuries people experience from explosions during combat. The researchers compared anxiety-like behavior and social motivation in this stress and TBI group to two groups who experienced either stress or TBI alone and another group that experienced none of these. Comparisons revealed sex-dependent differences in behavioral outcomes. Both male groups that experienced stress displayed similar anxiety and social behavior. But compared to the TBI alone group, stress increased anxiety while protecting some aspects of social motivation in the group of males that experienced both TBI and stress. Female rats with prior stress and TBI had mostly opposite effects regarding social motivation, but their anxiety behaviors were similar to the equivalent male group. Females with only TBI were the most motivated among female groups to socialize with new peers, which was not the case with TBI males. Says Vandevord, “This study really depicts the importance of looking at pre-existing conditions such as stress and sex and how they influence the outcomes of TBI.”
Most-Discussed Research Published in January and February
Below are five Early Release articles that generated the most online discussion in January and February 2025, as measured by Altmetric. Altmetric data is available for all articles published in eNeuro on the Info & Metrics tab. Learn more about how the Altmetric score is calculated.
Bell Jar: A Semiautomated Registration and Cell Counting Tool for Mouse Neurohistology Analysis
Studies elucidating the anatomical organization of the brain are becoming increasingly complex in neuroscience. Thus, need for tools that can sufficiently handle increasing complexity and throughput of experiments is also increasing. While many options currently exist for performing these analyses, most do not provide an all-in-one guided workflow. Due to this smattering of tools, many labs must develop custom solutions. However, only some researchers have the programming expertise to troubleshoot and combine existing platforms to achieve their desired results. This is why we created Bell Jar, an open-source, multi-platform semiautomated toolkit that is usable by researchers of all skill levels. Bell Jar’s semiautomated nature and ease of installation allow any lab to process its experimental data quickly.
Whether a person is trustworthy or might pose a risk to one's own health must be decided in a few moments and based on limited characteristics. The salience network as an “alarm system” should be involved in these evaluative processes. This paper reports the results of neural activation in trustworthiness judgments of naturalistic stimuli of persons precategorized as HIV+ or HIV−. We find activation in medial orbitofrontal cortex for people evaluated as trustworthy and for people precategorized as HIV−. For people judged as untrustworthy, activation in the insula, amygdala, anterior cingulate cortex, and nucleus accumbens is revealed. These findings suggest a safety signal in the medial orbitofrontal cortex and an involvement of the salience network in risk detection.
Multimodal Imaging to Identify Brain Markers of Human Prosocial Behavior
The objective of this study was to identify brain markers associated with human prosocial behavior using data from 15 major economic games and multimodal magnetic resonance imaging data. The results of the study suggest that specific brain indicators, including myelin density and resting-state interhemispheric functional connectivities, are associated with prosocial behavior. The use of a data-driven approach holds particular significance within the realm of social neuroscience, a field that grapples with a multitude of variables.
Microglia Morphology in the Developing Primate Amygdala and Effects of Early Life Stress
The paralaminar (PL) nucleus of the amygdala is an important source of plasticity, due to its unique repository of immature glutamatergic neurons. In rhesus macaques, similar to human, PL immature neurons mature between birth and adolescence. This maturation process is likely supported by synaptogenesis, which requires microglia. Between infancy and adolescence in macaques, PL microglia became denser and shifted to a “ramified” phenotype, consistent with increased synaptic pruning functions. Early life stress in the form of maternal separation, however, blunted this normal trajectory, leading to a persistent “hyper-ramified” microglial phenotype. We speculate that microglia hyper-ramification aligns with “para-inflammatory” concepts of stress and may alter PL neuronal maturation and synapse formation in young animals.
Repeated infusions of ketamine, an NMDAR antagonist, show sustained reductions in major depressive disorder (MDD). Given the high comorbidity between MDD and alcohol use disorder (AUD), we investigated the effects of a history of social isolation and alcohol on responding for ketamine. We showed sex differences in the effects of isolation stress and alcohol on ketamine intake alongside alterations in dendritic spine morphology in the nucleus accumbens. Overall, a history of alcohol consumption enhanced responding for ketamine. If extrapolated clinically, our research implies that adjustments in ketamine therapy should be made for individuals with a history of alcohol drinking undergoing treatment for MDD. Additionally, when formulating treatment protocols for this population, it is important to consider potential sex differences.
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