It has been widely believed that a key function of sleep is to actively clear metabolites and toxins from the brain. Miao, Luo et al. show in mice that brain clearance is markedly reduced—not increased—during sleep and anesthesia.

Physiologically relevant stimulation of dopamine neurons does not function as a reward and does not endow cues with a reward representation. However, high-frequency stimulation is represented as a sensory-specific goal that motivates behavior.

Neural activity does not always lie in a low-dimensional subspace. The authors extend this classic view to show that task-relevant information is distributed across multiple covariability classes and propose a new method, sliceTCA, to disentangle them.

Neuroinflammation and microglia significantly contribute to Alzheimer’s disease pathology, depending on their activation state. We found that TREM2-expressing microglia are a heterogenous population spanning activated to senescent cells.

How the brain tracks blood glucose dynamics is unclear. Viskaitis et al. show that hypothalamic orexin/hypocretin cells track glucose concentration and rate of change and that their activity is important for glucose-evoked locomotor suppression.

LINE-1 retrotransposons are a type of mobile DNA element normally repressed in the body. Here the authors show that LINE-1 sequences can jump in mouse parvalbumin interneurons and also promote the transcription of key parvalbumin interneuron genes.

Studying gene expression in admixed Black Americans, Benjamin et al. reveal genetic ancestry-linked differences impacting immune and vascular genes and potentially influencing neurological disease risk. These findings highlight the importance of considering ancestry in brain research.

The circuit mechanisms underlying emotion recognition are unclear. Here, Dautan et al. show a role for a long-range feedback loop comprising somatostatin inhibitory projections from the medial prefrontal cortex (mPFC) to the retrosplenial cortex (RSC) and excitatory feedback projections from the RSC to the mPFC.

Christenson et al. describe hue-selective neurons in the fruit fly optic lobe. Using a connectomics-constrained model combined with genetic manipulations of the circuit, they show that recurrent connections are critical for hue selectivity.

It has been widely believed that a key function of sleep is to actively clear metabolites and toxins from the brain. Miao, Luo et al. show in mice that brain clearance is markedly reduced—not increased—during sleep and anesthesia.

The increased inclusion of samples from individuals from minoritized communities in biomedical research will help to mitigate health disparities that stem from a medical enterprise founded in racism and exclusion. In this issue of Nature Neuroscience, Benjamin et al. investigate how genetic ancestry influences the expression of genes in the brain, an effort supported by community leaders who raised funding, partnered in shaping research questions and had a central role in the interpretation and communication of the study’s findings. Here, we outline the public and social context that motivated these efforts towards ensuring equitable access to the benefits of science for all.

Effective science communication is necessary for engaging the public in scientific discourse and ensuring equitable access to knowledge. Training doctoral students in science communication will instill principles of accessibility, accountability, and adaptability in the next generation of scientific leaders, who are poised to expand science’s reach, generate public support for research funding, and counter misinformation. To this aim, we provide a guide for implementing formal science communication training for doctoral students.