Reviews & Analysis

Complex and intelligent behavior depends not just on sensory evidence but also on internal cognitive state. Ashwood et al. use a powerful statistical method to identify hidden internal states in choice data.

Roy, Zhang et al. discuss how modern neuroscience is revealing underappreciated heterogeneity in thalamic cell types, which leads to the idea that ‘thalamic subnetworks’ provide a more appropriate level of functional description than thalamic nuclei.

Adult male rodents have long been known to show stronger hippocampal long-term potentiation (LTP) and learning than females. Le et al. find that this sex difference is reversed in pre-pubescent animals, and identify a female-specific mechanism that increases LTP threshold and decreases spatial memory in females after puberty.

The duodenum distinguishes between sugar and sweeteners, but the cells involved in this process remain elusive. Buchanan and colleagues engineered a flexible optic fiber for optogenetic manipulation of gut cells in mice. Silencing duodenal CCK cells reduced the preference for sugar over sweetener intake. Gut optogenetics may elucidate how the gut–brain axis regulates feeding and glucose homeostasis.

Neuroscientists can measure activity from more neurons than ever before, garnering new insights and posing challenges to traditional theoretical frameworks. New frameworks may help researchers use these observations to shed light on brain function.

Yang et al. demonstrate that sensory neurons are enriched for the anthrax toxin receptor-2. Edema toxin, which acts via this receptor, induces analgesia in mice and can also be engineered to deliver large cargoes such as botulinum toxin in order to selectively silence sensory neurons.

Allen et al. introduce the Natural Scenes Dataset — high-resolution fMRI data from eight individuals scanned as they collectively viewed more than 70,000 natural images and performed a continuous recognition task. This resource promises to yield insights into visual perception and memory and to help bridge cognitive neuroscience and artificial intelligence.

Our brains are wired to steer us toward novel experiences. Ogasawara et al. define nodes in a network that underlies novelty-seeking behavior distinct from novelty-orienting responses. In this network, anterior ventral medial temporal cortex (AVMTC) mediates novelty-related sensory processing, and zona incerta uses input from AVMTC to guide gaze shifts for novelty seeking.

The structural basis for the clinical and side effects of antipsychotic drugs has not been resolved. A new study combined X-ray crystallography with medicinal chemistry and behavioral pharmacology to design a new dopamine D₂ receptor partial agonist that, in mice, shows not only antipsychotic-like activity but also 5-HT_1A-receptor-dependent antidepressant-like effects.

This Review discusses evidence from human studies and mouse models that cortical interneurons are involved in the pathophysiology of autism and that parvalbumin cell hypofunction may be a primary driver of circuit dysfunction in autism.

Microglia form barriers that attenuate the propagation of amyloid pathology in Alzheimer’s disease. d’Errico et al. have uncovered a paradoxical ability of microglia to spread amyloid plaques, which depends on the transcription factor IRF8. Here, we highlight the contexts in which this may happen and discuss outstanding questions.

Describing cognitive processes without reference to their neural underpinnings has led to conceptualizations that do not match how the brain functions. A data-driven re-examination of the neuroimaging literature reveals an alternate conceptual framework combining mind and brain that disrupts current neuroscientific thought.

Using a deep neural network, Frey et al. are able to track participants’ eye movements using functional magnetic resonance imaging of the eyes. This technique can be applied across studies to new and old data alike, allowing retrospective analyses of past studies.

Myelin is traditionally perceived as inert and immutable, but this notion is now being challenged. de Faria et al. discuss how myelin changes throughout life and in response to experience, and consider the functional implications of these changes.

Positive and negative valence are encoded in specific neural populations of the basolateral amygdala, but only few of these populations have been characterized. A new study identifies a novel population, defined by the molecular marker Fezf2, and demonstrates that two of its output pathways differentially encode emotional valence.

Grid cells produce exceptionally regular firing patterns as animals navigate in 2D spaces. Two new studies show that in flying and climbing animals, the activity patterns of these cells in 3D space are irregular. These results reveal an unexpected way in which the brain represents spatial location.

In this Perspective, Tononi and colleagues argue that while knowledge of elementary mechanisms is enough to predict everything about the dynamics of a system, only the analysis of causal structures can provide a coherent account of ‘what caused what’.

Placental allopregnanolone affects oligodendrocyte differentiation and myelination in the developing cerebellum. Male mice deprived of allopregnanolone in utero show impaired sociability and communication in later life; their female littermates are unaffected. Allopregnanolone replacement restores normal myelination and behavior.

Everyday phrases like ‘top dog’ and ‘low status’ suggest that we may mentally represent social and spatial information similarly. To what extent is that true? New research suggests that, like physical space, social knowledge is encoded as a cognitive map in the human brain and represented with a grid-like code.

Visually guided behavior begins with inputs to sensory cortices, but the decision to initiate actions engages the frontal cortex. A new study dissects a microcircuit for visual-to-motor transformation in the anterior cingulate cortex of the mouse with implications for impulsivity and disease states.