Reviews & Analysis

Crone and Dahl review functional imaging studies of cognitive, affective and social processing in adolescents. They suggest that, together with the development of cognitive control networks, changes in social and affective processing in adolescence may both confer adaptive advantages and induce vulnerability to risky behaviours.

Improvement in the performance of a newly acquired skill with training occurs gradually over time. Here, Censor, Sagi and Cohen highlight similarities in such procedural learning between the motor and perceptual domains and suggest that a common mechanism supports this type of learning in various domains.

The semaphorins have integral roles in various processes that underlie the development of neural circuits. In this article, Jeroen Pasterkamp explores novel aspects of neuronal semaphorin receptor regulation before discussing recent research into the involvement of semaphorins in establishing complex neuronal connections.

In this Review, De Zeeuw and colleagues discuss the types of plasticity that occur at different synapses within the cerebellar cortex. They propose that the distributed and synergistic character of the various forms of plasticity promotes optimal motor learning.

It is commonly thought that fear induced by distinct stimuli is processed by a single 'fear circuit'. Gross and Canteras discuss evidence showing that separate, parallel pathways process different types of innate fear but a common mechanism underlies the encoding of learned fear for all classes of stimuli.

The recent characterization of non-coding RNAs and their astonishingly diverse functions has led to a radical shift in our understanding of how the genome influences neuronal function. In this Review, Qureshi and Mehler describe the numerous classes of non-coding RNAs and how they might contribute to neuronal physiology and disease.

Bodily self-consciousness includes the conscious experience of identifying with the body, of where 'I' am in space, and of the perspective from where 'I' perceive the world. Olaf Blanke discusses the cortical mechanisms that underlie these experiences, highlighting data from neuroimaging, neurology and virtual reality.

The α₂δ and β subunits of voltage-gated calcium channels (VGCCs) modulate the biophysical properties and trafficking of such channels. In this Review, Annette Dolphin examines the traditional roles of these auxillary subunits and their involvement in neuronal processes that are not linked to VGCC function.

Recent studies show that oestradiol, the classic female oestrogen, can be locally synthesized by central auditory neurons to rapidly modulate neuronal physiology and auditory-based behaviours in both sexes. Pinaud and Tremere review these findings, which indicate that oestradiol is an important, novel modulator of hearing function.

Decision making is influenced by uncertainty, which arises from internal and external noise. A fundamental question is how uncertainty is encoded in the brain and how it influences behaviour. In this Review, Bach and Dolan integrate several theoretical concepts about uncertainty into a hierarchical decision-making framework.

Neurons in the human medial temporal lobe respond in a selective and abstract manner to particular persons or objects. Rodrigo Quian Quiroga argues that these 'concept cells' are crucial for memory functions and the transition between related concepts that leads to the flow of consciousness.

Recent improvements in the technology available for the analysis of genetic variability have revolutionized the study of many diseases. Hardy and colleagues illustrate how genome-wide strategies, including whole-genome and whole-exome sequencing, have been used to improve our understanding of the pathobiological mechanisms of neurological diseases

Multiple sclerosis (MS) is generally considered to be an autoimmune, inflammatory disease. In this provocative Perspective, Stys and colleagues propose that non-inflammatory, primary progressive MS is the 'real' MS, and that inflammatory forms of the disorder reflect an aberrant immune reaction to ongoing cytodegeneration.

Functional MRI studies have revealed useful information about the ageing brain. In this Review, Cheryl Grady explains how correlating cognitive decline to changes in brain structure and function is hampered by the complexity of the ageing process.

Behavioural learning is accompanied by loss and gain of synapses, which is thought to be the mechanism by which circuits are altered and 'memory traces' established. Recent research, reviewed here, suggests that learning and memory events involve the rearrangement of ensembles of adjacent synapses on short stretches of dendrites.

Tryptophan metabolism along the kynurenine pathway generates several neuroactive metabolites. Schwarcz and colleagues discuss the regulation of this pathway in the normal brain and in neurological and psychiatric disorders, and consider the potential therapeutic opportunities of targeting this pathway.

Neuronal activity in the brain gives rise to transmembrane and extracellular electromagnetic fields that can be measured in the extracellular medium using several approaches. In this Review, Buzsáki and colleagues provide an overview of the mechanisms that underlie the generation of extracellular currents and fields.

GABA_B receptor activity is integral to the proper functioning of many neural systems. In this Review, Gassmann and Bettler examine our understanding of the subunit composition of such receptors and how this affects GABA_Breceptor properties, neuronal processes and higher brain functions.

Caspases are most well known for their role in programmed cell death (apoptosis), but more recently, it has emerged that when caspases are expressed in a localized and restricted manner, they can regulate normal physiological functions such as circuit refinement through axon pruning and synapse elimination.

The use of sophisticated molecular and genetic techniques has revealed the complexity and diversity of the protein composition of different synapses. Smith and colleagues describe methods for investigating synaptic diversity and show how knowledge gained from these studies can advance our understanding of neural circuit organization and function.