Volume 22 Issue 6, June 2019

Using light-activated ion channels to stimulate sensory and motivational pathways, Vetere and colleagues constructed fully artificial memories in mice. Mice preferred or avoided an odor they had never smelled before, depending on the pattern of stimulation.

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.

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.

The authors generated a mouse model of C9ORF72-related amyotrophic lateral sclerosis and frontotemporal dementia based on dipeptide repeat proteins and report that defects in mitochondria may contribute to disease pathogenesis.

The (G4C2)₃₀₊ repeat expansion is the most prominent mutation in familial FTD and ALS. Here the PAF1 complex is identified as a transcriptional regulator of this unique mutation. Data from FTD tissue positive for the C9orf72 mutation support the relevance of this complex in disease.

Lu et al. report a pathway that reprograms protein quality control under stress. Identified in a Caenorhabditis elegans screen and characterized in mammalian systems, L3MBTL1 and its partner SETD8 modulate proteotoxicity and are deregulated in patients with ALS/FTD.

The authors report that the presynaptic protein bassoon forms toxic aggregates in neuronal somata in multiple sclerosis. Stimulation of proteasomal activity reduces bassoon aggregates, neuroaxonal loss and disability during CNS inflammation.

Aydin et al. show that the proneural factors Ascl1 and Neurog2 bind to largely non-overlapping sites in the genome, establishing distinct chromatin landscapes that shape the activity of downstream factors during neuronal fate specification.

How does the mammalian brain trigger prey-capture behavior? Shang et al. identify a subcortical circuit that transforms prey-derived sensory cues into predatory attack signals during hunting behavior in mice.

Sensory detection of prey triggers hunting actions in predators. Zhao et al. show that the zona incerta integrates prey-related multisensory signals and induces a motivational drive to guide prey detection and promote predatory attack.

Pairing an odor conditioned stimulus (CS) with an unconditioned stimulus (US) induces memory formation. Vetere et al. replace the real CS and US with direct optogenetic stimulation of the brain and create a fully artificial odor memory in mice.

Dong, Wang et al. uncover a circuit linking Glu⁺cingulate inputs→PV⁺ neurons in the limbic thalamic reticular nucleus→intermediodorsal thalamic nucleus, and show that this cortico-intrathalamic circuit is a component of the fear circuitry and controls flight behavior in mice.

Cerebellar climbing fibers carry predictive and feedback signals about reward, expanding the role of the cerebellar cortex in the creation and evaluation of predictions.

Using a new auditory decision task, neuronal imaging and perturbations, Zhong et al. unveil the critical role of PPC circuits in decision-making when categorizing unknown sensory items.

Using model- and primate behavior-driven image selection with large-scale electrophysiology in monkeys performing core recognition tasks, Kar et al. provide evidence that automatically engaged recurrent circuits are critical for rapid object identification.

The brain predicts future sensory input. The authors hypothesize that the visual system achieves this by straightening the temporal trajectories of natural videos, and they provide evidence using human perceptual experiments and computational modeling.

Ziegler, Hauser et al. report brain-wide, myelin-related microstructural growth from adolescence to adulthood and show that this longitudinal growth is reduced in the presence of compulsivity and impulsivity traits.

Why do certain individuals learn faster than others, and how does the acquired information take shape within their brains? Tang and colleagues show that fast learners encode information in a particularly compact, efficient and space-saving manner.

The authors discover neurons in the human prefrontal cortex that encode subjective decisions and that may underlie the process by which opinions are formed. They also find how disruption of these neurons selectively interferes with the decision-making process.

Van Hove et al. reveal the diversity of macrophages at the brain’s border regions via single-cell analysis and fate-mapping. This also identified a microglial subset at the surface of the choroid plexus, in direct contact with cerebrospinal fluid.