Updated September 4th, 2024
Research Spotlight
Men and women exhibit differences in many behaviors that are important for survival and are relevant to mental health, including behaviors related to seeking and acquiring rewards. Copenhaver and LeGates have identified the use of sex-specific mechanisms for synaptic plasticity in a circuit that influences reward-related behaviors. Their research has significant implications for understanding the neurobiology underlying sex differences in motivated behaviors and their potential relevance to neuropsychiatric disorders.
An enhanced peripheral chemoreflex leads to hypertension and cardiovascular disease. In this paper Musa and colleagues provide evidence that orexin neurons in the perifornical hypothalamus increase the strength of the peripheral chemoreflex through the activation of corticotropin-releasing hormone neurons in the paraventricular nucleus that project to the nucleus of the solitary tract. Orexin and its receptors may be fruitful targets for strategies aimed at reducing the morbidity and mortality caused by high peripheral chemoreflex sensitivity.
Dirani and Pylkkänen explored how our brains access semantic knowledge from different types of stimuli, such as pictures and words. The study used a novel method with neural networks to learn patterns of representation from brain data, revealing the consistent information the brain accesses, regardless of whether participants were looking at words or pictures. The results showed that these representations include both semantic and visual elements, suggesting that our brains store concepts in a rich, multi-faceted way, beyond just semantic representations.
Most-Discussed Research Published in August
Below are five Early Release articles that generated the most online discussion in August 2024, as measured by Altmetric. Altmetric data is available for all articles published in JNeurosci on the Info & Metrics tab. Learn more about how the Altmetric score is calculated.
Decision-Making with Predictions of Others' Likely and Unlikely Choices in the Human Brain
In daily life, to adjust our decisions, we constantly predict others' choices, but the inherent uncertainty means we face multiple scenarios for different choices by others. Using computational modeling-based fMRI, we identified a network in three-stage computations for such decision-making. Amygdala signals represent predictions of others' choices. These signals then interact with the posterior cingulate cortex and dorsolateral prefrontal cortex, representing the decision variables for the prediction of others' likely and unlikely choices, respectively. Finally, these signals modulate the medial prefrontal cortex, influencing our final choices. These pivotal variables and their corresponding brain signals play a fundamental role in a broad range of social cognitive processes. Our findings shed light on underlying mechanisms for complex social interactions in human behavior.
A Multidimensional Neural Representation of Face Impressions
People form trait impressions based on facial features, which operate like facial stereotypes that bias social decision-making and shape real-world outcomes in career, legal, and political domains. We show that the brain represents others' faces as points in a two-dimensional space tracking trustworthiness and dominance. One brain region, involved in the activation of conceptual attributes, automatically represented this trait space in response to faces, even if participants did not explicitly endorse the use of facial stereotyping. Other regions, involved in the social reasoning of others' internal qualities, also represented this trait space, but only among participants who endorsed facial stereotyping. The findings reveal how harmful biases based on facial appearance arise in the brain through multiple implicit and explicit mechanisms.
Our analysis revealed two distinct temporal clusters of sleep spindles in primary motor cortex—train spindles (which are spaced closely together in time) and isolated spindles (which do not have neighboring sleep spindles). Train spindles were distinct from isolated spindles exhibiting stronger M1 SO locking and increased M1 SO-spindle nesting. Moreover, we showed that coupling between mPFC-M1 SOs influenced generation of M1 train spindles and strongly correlated with increased degrees of M1 SO-spindle nesting. In fact, we found that spindle trains themselves were especially enriched in close mPFC-M1 SO locking which coincided with enhanced M1 SO-locked spiking modulation. Finally, we demonstrated that train spindles were privileged windows for sustained task-related memory reactivation. These phenomena suggest key mechanisms through which cross-area SO propagation drives entrainment of M1 spindle trains thus supporting sensorimotor learning via sustained memory reactivations in M1. More broadly, this work advances our understanding of how global activity during sleep assists in localized consolidation of task-specific memories.
Understanding mechanisms of synaptic dysfunction in Alzheimer's disease (AD) is pivotal for therapeutic advances. Amyloid-β oligomers (Aβo), primary culprits in AD pathology, disrupt critical synaptic plasticity mechanisms, leading to enhanced LTD and synaptic loss. However, the underlying signaling pathways remain elusive. Calcineurin (CaN), localized by AKAP79/150 at synapses, plays a key role in LTD formation. Inhibition of CaN mitigates Aβo-induced synaptic deficits, implicating its involvement in AD pathology. Our study shows that AKAP-anchored CaN is critical in acute Aβo-mediated inhibition of NMDAR Ca2+ signaling and dendritic spine loss. Additionally, we identify mGluR1 as an upstream regulator of these Aβo-induced deficits, highlighting several potential therapeutic targets for AD-related synaptic pathology.
The mesolimbic dopamine (DA) system is known to play a crucial role in motivation and reward-learning and receives neuromodulatory input from the lateral hypothalamus (LH). We show that optical stimulation of the orexin-containing LH input in the VTA releases both orexin and dynorphin to bidirectionally alter VTADA firing. Furthermore, orexin and dynorphin differentially modulate firing of DA inputs to the basolateral amygdala, whereby dynorphin predominates, or to the nucleus accumbens which is sensitive to both neuromodulators. Our findings contribute to a more comprehensive understanding of the neuromodulatory effects of coreleased LH orexin and dynorphin on the VTADA system.
Stay updated on the latest research: Sign up and manage your Alerts to receive email alerts of table of contents, searching, and article citation alerts for both issues and Early Release.