Research articles

Social interactions and relationships are often associated with a rewarding experience. Hu et al. show that mice display positive reinforcement of social interaction, and they identify an amygdala-to-hypothalamus circuit in mediating this social reward.

The authors develop a genetically encoded GPCR-based sensor to image serotonin dynamics in behaving animals with high specificity, sensitivity and spatiotemporal resolution.

During implicit learning, the authors find that sensory representations in mouse auditory cortex evolve over time, rotating into orthogonal memory representations. This allows short-term memories to avoid interference from new sensory inputs.

This study shows that hippocampus-dependent fear memories can be indirectly reactivated, captured and pharmacologically attenuated in rats. This reinforces the utility of imaginal reminders to target traumatic memories in humans.

AAV9-SMN is used to treat SMA. This study shows that AAV9-mediated SMN overexpression in mice causes late-onset motor dysfunction and synaptic and neuronal loss through protein aggregation, suggesting caution on the long-term safety of SMN gene therapy.

El-Gaby et al. combine multiunit recordings and optogenetic silencing in the mouse hippocampus and uncover a primary role for millisecond-timescale neural coactivity in encoding behavioral contingency information and supporting memory retrieval.

Although successful memory recall usually involves activation of broadly distributed networks, Vetere, Xia et al. show that the active disengagement of the anterodorsal thalamic nucleus is necessary for recall specifically at remote time-points.

Single-cell RNA-seq and CITE-seq were used to profile the glioblastoma immune landscape in humans and mice, revealing the diversity and dynamics of tumor macrophages as the disease progresses from initial diagnosis to recurrence.

Hennig et al. study how changes in internal state interact with learning in primates. They report stereotyped activity fluctuations in the motor cortex that reflect the animal’s level of engagement and predict how quickly the animals learned.

Combining virtual reality and large-scale calcium imaging, the authors demonstrate that hippocampal place cell remapping across contexts can be precisely predicted by the experience of the animal and approximates optimal probabilistic inference.

Yin et al. show that motor learning is delayed in mice with 16p11.2 deletion, associated with abnormal ensemble activity and delayed spine remodeling in motor cortex and reduced activity of of locus coeruleus noradrenergic neurons. The motor-related abnormalities were rescued by activation of ocus coeruleus noradrenergic neurons.

Astrocytes regulate synaptic transmission. Carlsen et al. report that spinal astrocytes activated by endocannabinoids inhibit excitatory synaptic transmission and, thereby, decrease tremor.

Eze et al. use single-cell sequencing and immunohistochemical validation to create an atlas of early human brain development. In the telencephalon, they discover a diversity of progenitor subtypes, including two that are enriched in humans.

Early life stress (ELS) promotes susceptibility to the effects of chronic stress in adulthood. Kronman et al. show that ELS alters H3K79me2 in D2 medium spiny neurons in the nucleus accumbens and that this underlies the susceptibility to the effects of subsequent stress.

The authors define two functionally distinct external globus pallidus basal ganglia pathways and their differential contributions to motor and cognitive Parkinsonian deficits in mice.

We propose that synapses compute probability distributions over weights, not just point estimates. Using probabilistic inference, we derive a new set of synaptic learning rules and show that they speed up learning in neural networks.

Pain hypersensitivity can result from tissue injury and from depression. This study in mice shows that distinct thalamocortical pathways mediate allodynia associated with injury and a stress-induced depression-like state, respectively.

Rare rewards amplify dopamine neuron responses, even when conventionally defined prediction errors are identical. This suggests that individual dopamine neurons are sensitive to predicted reward distributions and can facilitate the learning of complex incentive structures.

Berto et al. combine human intracranial brain oscillations recorded during mnemonic processing and measures of gene expression from brain tissue surgically removed from the same individuals to uncover gene expression patterns relevant to memory in humans.

Spikes of deep-layer ID2⁺Nkx2.1⁺ cortical neurons are anticorrelated with spiking of all principal cells and interneurons, prominently during down states of sleep, and shape the sequential firing of neurons at down–up transitions.