Reviews & Analysis

MicroRNAs have crucial regulatory roles at the post-transcriptional level and are emerging as key players in the development of the nervous system in many species. In this Opinion article, Kosik discusses how these non-coding transcripts could drive evolutionary change.

Tracing the phylogeny of the molecular components of synapses, Ryan and Grant speculate on the core components of the last common ancestor of all synapses and posit that the diversification of upstream signalling components contributed to increased signalling complexity later in evolution.

By comparing developmental gene expression and neuroanatomy of vertebrates and the basal chordate amphioxus, Linda Holland sheds light on the molecular changes that may have facilitated the evolution of the vertebrate brain.

WNTs are largely thought of as regulators of cell fate but recent studies highlight their involvement in synaptic development. Korkut and Budnik discuss emerging data on the effects of WNT signalling in neuromuscular junction formation in nematodes, insects, fish and mammals.

The formation and elimination of axonal boutons and dendritic spines is continuously taking place in the adult mammalian brain. Holtmaat and Svoboda review this structural plasticity and its dependence on cell type, sensory experiences and learning.

The connections in the cerebellum are highly complex, and different experimental approaches have resulted in several maps of cerebellar organization. Reviewing anatomical, physiological and molecular studies, Apps and Hawkes show that different maps might represent facets of a common topography.

Protein expression levels and protein interactions are dynamic, cell type-specific and dependent on the brain region. Bayés and Grant review how neuroproteomic studies have contributed to elucidating basic physiological and pathophysiological mechanisms and point to the further potential of such studies.

Studies into the role of different frontal cortex areas in cognitive control have suggested that there is a rostral-to-caudal processing gradient. Drawing on anatomical and functional data from humans and monkeys, Badre and D'Esposito discuss whether this gradient might reflect a hierarchical organization.

Biomaterials can be used to deliver drugs, cells and tissue transplants into regions of the brain damaged by neurodegenerative disease or trauma. Emerich and colleagues describe currently available biomaterials and show how the ability to manipulate biomaterial–cell interactions will improve their usefulness.

In this provocative Perspective, Jerry Siegel shows that many aspects of sleep differ greatly between species and conditions, such that a universal, vital function of sleep is unlikely. He argues that sleep benefits animals simply by increasing the efficiency of their activity.

During the past decade it has become clear that the regulation of sleep is conserved across species. Cirelli discusses the genes that have been identified in sleep regulation and how sleep regulates the expression of genes in the brain.

The neurobiological underpinnings of anorexia nervosa are not well understood. Kaye and colleagues discuss how alterations in neurotransmitter systems and in the interacting brain circuits underlying reward, interoception and appetite might contribute to the vulnerability to and symptoms of this disorder.

The olfactory glomeruli represent a remarkable example of nervous system organization — each glomerulus is innervated exclusively by sensory neurons expressing one of more than 1,000 olfactory receptors. Firestein and colleagues discuss recent insights into glomerular development that highlight the importance of signalling activity in this process.

How a reduction in the level of a ubiquitously expressed protein, SMN, causes the motor neuron–specific deficits that characterize spinal muscular atrophy is unknown. Burghes and Beattie discuss the function of SMN and the debate concerning the crucial pathways disrupted in SMA.

In addiction, the prefrontal cortex fails to control drug-seeking behaviours. Peter Kalivas reviews the hypothesis that a loss of glutamate homeostasis at prefrontal-to-accumbens synapses, resulting in altered dendritic spine morphology and synaptic plasticity, impairs the prefrontal regulation of striatal circuitry.

GIRK and SK channels, two families of voltage-independent K⁺channels, have recently been described at synaptic as well as extrasynaptic sites. Luján and colleagues discuss how associated signalling complexes in conjunction with local signals could result in the different functions of these two ion channel families.

What sets highly skilled sportspeople apart from novices? This article discusses the neural basis of sporting skills and emerging computational and physiological theories that help explain, and potentially predict, elite athletic performance.

Intrinsic spinal cord networks generate the rhythmic patterns of motor activity that underlie locomotion. Goulding shows how genetic analyses, coupled with classical systems neuroscience approaches, are providing new information about the cellular components and functional organization of these circuits.

Recent advances in brain–machine interface technology have allowed neuroscientists to gain insights into the principles underlying information processing in the CNS. Nicolelis and Lebedev propose a series of principles of neural ensemble physiology that have arisen from this research.

Kroemer and colleagues discuss the converging signalling mechanisms that lead to mitochondrial membrane permeabilization and trigger neuron death after severe brain injury. They also highlight how knowledge of these mechanisms might be exploited therapeutically.