Perspectives

The functional roles of the striatal indirect pathway remain unclear. In this Perspective, Lee and Sabatini propose that a three-factor learning rule governs the activity of indirect striatal projection neurons, contributing to the learnt avoidance of actions with negative outcomes and the transition to alternative actions.

In this Perspective article, Edward Large and colleagues examine the neuroscience of music, placing their focus on neural resonance theory, which summarizes how the dynamics of fundamental neural mechanisms can explain various aspects of music perception and performance.

In this Perspective, Barabási, Ferreira Castro and Engert challenge the notion that learning and plasticity primarily drive the assembly of neural circuits. They present a tripartite framework for how neural circuits form, outlining the relative contributions of developmental, associative learning and tuning-based factors to this process and knowledge acquisition.

Midbrain dopamine neurons are widely assumed to signal a unidimensional value-based prediction error. In this Perspective, Kahnt and Schoenbaum overview accumulating evidence that challenges this assumption, highlighting the need for a new theory on the role of dopamine in error-based learning that goes beyond value.

A computational account of how schemas are learned through experience is lacking. In this Perspective, Bein and Niv synthesize schema theory and reinforcement learning research to derive computational principles that might govern schema learning and then propose their mediation via dimensionality reduction in the medial prefrontal cortex.

Cerebral small vessel disease is a common cause of dementia and stroke. In this Perspective, Wardlaw and co-workers describe evidence from human brain imaging and preclinical models that points to dysfunction in the endothelial cells that line the walls of cerebral blood vessels as a key driver of small vessel disease.

The brain enters an action-mode of function during goal-directed behaviour. In this Perspective, Dosenbach, Raiche and Gordon describe “action-mode” as an informative functional label that reduces anatomical network naming confusion, then characterize how the reannotated action-mode network supporting it counterbalances the default mode network.

Substance-use disorders (SUDs) are characterized by chronic relapse. However, many of those affected eventually do achieve recovery. Engeln and Ahmed describe insights from clinical and preclinical studies of remission that suggest that recovery from substance-use disorders involves both reversal of drug-induced circuit changes and new neural circuit adaptations.

Advances in tools available to monitor and manipulate neural activity in freely moving animals can enable the investigation of naturalistic behaviours. In this Perspective, Gross and colleagues outline the challenges that neuroscientists face when incorporating ethological context into studies of fear, aggression and dominance and provide suggestions to overcome these barriers.

How the brain routinely processes information from different sensory modalities during everyday tasks is not well understood. In this Perspective, Engel and Senkowski propose how oscillatory neural mechanisms operating at multiple timescales within and across brain networks can mediate such multisensory integration.

There are a number of models that have attempted to explain why people with Parkinson disease move slowly. In this Perspective, Williams identifies the inconsistencies in these models and suggests that these may be addressed by a different model that considers disordered information transmission as fundamental to slow movement development.

The location-specific firing of hippocampal place cells changes when an animal enters a new environment, a phenomenon known as ‘remapping’. In this Perspective, André A. Fenton challenges standard models of place cell remapping and proposes a key role for the ‘re-registration’ of internally organized place cell population dynamics in the encoding of distinct environments.

Sleep is an active state during which the synaptic connections that form memories are remodelled. In this Perspective, Wassing and colleagues discuss how failures in sleep-dependent adaptation to emotionally distressing experiences might be a key contributor to post-traumatic stress disorder and related conditions.

Altered network activity during sleep is observed in some individuals with Alzheimer disease and in mouse models of the disorder. In this Perspective, Inna Slutsky proposes that hyperexcitability and sleep disturbances in Alzheimer disease result from disruption of the mechanisms that maintain activity homeostasis in the brain.

Sub-additive responses to simultaneously presented stimuli and quenching of variability in responses to repeated presentations of a stimulus are characteristics of neurons in the primary visual cortex. In this Perspective, Goris et al. argue that these phenomena often co-occur and may have common mechanistic and computational origins.

Synaptic engineering involves the synthetic insertion of new synapses between neurons in vivo. In this Perspective, Rabinowitch, Colón-Ramos and Krieg explore this emerging approach for studying neural circuits, describing the different methods that have been used and how they have been implemented.

Neurobiological organizational principles suggest that a generative grammar exists in the brain. In this Perspective, Dragoi proposes how neural grammar enables specific experience-independent, internally generated patterns of activity acquired via spontaneous generative combination of pre-existing sequential motifs to support internally generated representations of experience in the hippocampus.

Architectures in neural networks commonly assume that inference is hierarchical. In this Perspective, Suzuki et al. present the shallow brain hypothesis, a neural processing mechanism based on neuroanatomical and electrophysiological evidence that intertwines hierarchical cortical processing with a massively parallel process to which subcortical areas substantially contribute.

The prospects for applying dynamical systems theory in neuroscience are changing dramatically. In this Perspective, Durstewitz et al. discuss dynamical system reconstruction using recurrent neural networks to directly infer a formal surrogate from an experimentally probed system and consider its potential for revolutionizing neuroscience.

Song and speech may have distinct roles in human communication. Scott and colleagues describe the mechanisms underlying the production and perception of song and speech, evaluate the evidence for distinct song-processing mechanisms in the human brain, and consider the implications of such specialization.