Reviews & Analysis

A new study shows that the enzyme monoamine oxidase funnels a byproduct of dopamine metabolism, H₂O₂, directly into the mitochondrial electron transport chain, stimulating ATP production. This alternative energy pathway may protect dopaminergic neurons from the toxicity induced by dopamine metabolism while supporting phasic firing.

Humans and animals are drawn to others in an altered affective state, whether sad or happy. A study published in this issue of Nature Neuroscience shows that a specific population of interneurons in the brain is critical for discrimination of affective states.

Behavior is more than the motor outputs that we can directly measure. Here Calhoun and colleagues devise a novel method for inferring the internal states that affect how fruit flies process sensory information during courtship, providing a new framework for understanding the neural encoding of behavior.

Reitich-Stolero and Paz examined multineuron correlates of Pavlovian learning in the primate amygdala. They found repeating patterns of activity across neurons that may mediate synaptic-level plasticity mechanisms. This extends the notion of replay, often examined relative to navigation in the hippocampus, to aversive learning in the amygdala.

Unexpected experiences often lead to strong memories. A new study by Krabbe and Paradiso et al. shows that vasoactive intestinal peptide (VIP)-expressing interneurons of the basolateral amygdala control associative learning and memory formation by gating aversive stimuli scaled by their unexpectedness.

Two new studies demonstrate the importance of awake imaging to investigate microglia–neuron interactions. These studies show that microglial dynamics are influenced by neuronal activity, and they provide evidence that norepinergic signaling plays an important role in this effect.

Astrocytes are crucial contributors to brain homeostasis. Yet the lack of ad hoc analysis tools has prevented in-depth characterization of astrocyte-derived signals. In a new study, the authors present an image-analysis toolbox that captures the complexity of astrocyte activity and enables our understanding of astrocytic physiology.

Using data from 45,615 people, Kaufmann et al. compare the gaps between brain age and chronological age in a number of brain disorders and study the relationship of these gaps with genetics. Their research shows that the brains of individuals with a range of different brain disorders, such as dementia and schizophrenia, are aging faster than normal.

We express decisions through movements, but not all movements matter to the outcome. For example, fidgeting is a common yet ‘nonessential’ behavior we exhibit. New evidence suggests that this non-task-related movement profoundly shapes neural activity in expert mice performing tasks.

A new study sheds light on how sensitivity to communication sounds is established in the brain. Juvenile finches raised with tutors of either the same or different species always learned the tutors’ songs. Cortical neurons developed selectivity for the learned song by tuning for its secondary acoustic features.

Chronic pain is associated with anxio-depressive comorbidities, but the neuroanatomical substrates remain unknown. A specific serotonergic pathway from the dorsal raphe nucleus to the lateral habenula via the central amygdala is now uncovered as a key neural circuit governing comorbid depressive symptoms in chronic pain.

Repeat-associated non-AUG (RAN) translation generates toxic repeat proteins from pathological repeat expansions found in certain neurodegenerative disorders, including amyotrophic lateral sclerosis and frontotemporal dementia. How to suppress RAN translation has so far been unknown. A new study now reports a selective regulator of RAN translation identified in a genetic screen in yeast.

Misfolded protein aggregates are a classical hallmark of many neurodegenerative diseases. By combining a mouse model of misfolded protein injection and a brain network model of misfolded protein diffusion, a study now finds a strong link between the stereotypical spreading patterns of neurodegeneration, protein expression and anatomical connectivity.

Mosquito-borne virus infections, such as West Nile and Zika, have debilitating cognitive effects that persist despite recovery from encephalitis. Garber et al. identify mechanisms by which antiviral T cell persistence after recovery from infection leads to impairments in cognition via virus-specific mediation of microglial synapse elimination.

Shahmoradian and colleagues report that the structure of Lewy bodies in Parkinson’s disease consists of α-synuclein and lipid vesicle clusters instead of the long-assumed amyloid fibril core. This finding has implications for our understanding of the underlying pathogenesis of synucleinopathies.

The creation of a murine Cre driver specific to CNS capillary pericytes has opened a major bottleneck in brain microvascular research. Using this tool, pericyte loss in the adult brain is shown to induce neuronal loss due to concurrent microcirculatory failure and depletion of the protective trophic factor pleiotrophin.

A new study by Owen et al. shows that widely used optogenetic light delivery can heat brain tissue and produce changes in neural activity and behavior in the absence of opsins. How will this finding influence experimental design in the optical age of neuroscience?

Selecting the most rewarding action and performing it accurately are two separable brain functions that are thought to rely upon different neural systems. New evidence suggests that the cerebellum could learn to do both.

How to know when to hunt or when to lay low? Surprisingly, new research shows that activity in the medial zona incerta specifically initiates predation in the mouse. The medial zona incerta integrates visual motion and tactile stimulation sent from the intermediate superior colliculus to motivate hunting.

The CNS harbors distinct subsets of macrophages, including parenchymal microglia and macrophages residing at border regions (for example, meninges and the choroid plexus). In this issue of Nature Neuroscience, Van Hove and colleagues elegantly demonstrate the diversity and dynamics of non-parenchymal macrophages and identify a unique microglial subtype within the choroid plexus.