Review Articles in 2010

What does resting-state network (RSN) activity actually reflect? Deco and colleagues review computational models showing that local dynamics, signal transmission delays and noise contribute to emerging RSNs. They propose that multiple functional connectivity patterns can be expressed around the same anatomical framework, and that the resting brain explores these possible configurations.

Since its proposal in 1997, the synaptic tagging and capture hypothesis has been highly influential in furthering our understanding of memory persistence. Data that have emerged in the intervening years have necessitated a revision and expansion of the original concept, which is discussed in this Review by Redondo and Morris.

Hereditary spastic paraplegias (HSPs) are genetic disorders that cause a length-dependent, distal axonopathy of the corticospinal tract. Reid and colleages review the molecular cell biology underlying HSPs and consider the importance of membrane trafficking and organelle morphogenesis in axonal development and maintenance.

Neurons in the dorsal horn of the spinal cord process sensory information and transmit it to the brain. Andrew Todd describes the complex neuronal organization and circuitry of this region and discusses the changes in the dorsal horn that that could underlie hyperalgesia and allodynia.

Sensory synapses of the auditory and visual systems need to encode a wide dynamic range of stimuli. Matthews and Fuchs discuss how it is increasingly certain that the ribbon synapse, a highly specialized structure capable of sustained and rapid transmitter release, plays a key part.

Nogo proteins inhibit axonal regeneration after injury, but recent studies have shed light on their physiological role in the intact CNS. Martin Schwab reviews the current knowledge of the complex receptor interactions of Nogo proteins and their role in stabilizing CNS wiring during development and in adulthood.

Recent research has revealed similarities between speech and birdsong on different levels. Bolhuis et al. discuss parallels between humans and songbirds in terms of vocal learning, the neural networks underlying vocalization and the role of FOXP2, highlighting both general and species-specific principles.

The extracellular matrix (ECM) plays a key part in diverse cellular processes. Dityatev and colleagues review how the ECM can have opposing effects on neuronal function — promoting plasticity or homeostasis of synaptic contacts — depending on the physiological context and regulation by key proteases.

In this Review, Redgraveet al. provide an updated model of basal ganglia architecture in which spatially segregated functional territories contribute to goal-directed and habitual control circuits. They propose that in Parkinson's disease, selective dopamine loss impairs habitual control and distorts goal-directed behaviours.

Activation of NMDARs can both promote neuronal health and kill neurons. In this Review, Hardingham and Bading discuss the downstream effects of stimulation of synaptic NMDARs and extrasynaptic NMDARs that result in promotion of neuroprotection and cell death, respectively.

Emotional stimuli, such as a fear-expressing face, can be processed without being consciously perceived and can influence behaviour. Tamietto and de Gelder describe the subcortical pathway that processes such stimuli, and discuss whether subcortical versus cortical processing of stimuli translate into non-conscious versus conscious perception. An interview with Beatrice de Gelder for Neuropod is available for download.

Reliable propagation of spiking activity in the brain is vital for information processing. Kumar, Rotter and Aertsen now propose that under certain conditions asynchronous and synchronous propagation of spiking activity can co-exist in a modular neuronal network, and they suggest experimental strategies to test this hypothesis.

The brain encodes representations of smells through the synthesis of different olfactory inputs into a unified whole. Jay Gottfried discusses the central mechanisms of perception of these 'odour objects' and describes the role of the piriform cortex in this process.

Glycogen synthase kinase 3 (GSK3) proteins and their upstream and downstream regulators have key roles in neurodevelopmental processes. Hur and Zhou review the mechanisms that regulate GSK3 activity and discuss how GSK3 controls neurogenesis, neuronal polarization and axon growth.

All retinal neurons are generated from multipotent progenitor cells through a step-wise process that increasingly restricts lineage choices. Swaroop and colleagues discuss our current understanding of the transcription factors and gene-regulatory networks involved in photoreceptor subtype specification and photoreceptor development.

Circadian cycling of biological processes is widely conserved across phylogeny. Gerstner and Yin discuss how regulators of circadian rhythms — including clock genes, melatonin and the suprachiasmatic nucleus — affect synaptic plasticity and memory formation.

Polarity is an essential requirement for neuronal function. Matthew Rasband describes the role of the axon initial segment in the development and maintenance of neuronal polarity and discusses how its disruption can lead to disorders of the nervous system.

The habenula is present in vertebrate brains but its function has remained obscure. Okihide Hikosaka reviews data from animal and human studies that indicate that the habenula, through its effects on dopamine and serotonin systems, regulates motor suppression in various contexts.

The diagnosis of autism is based on behavioural criteria. Robust phenotypes in mouse models hold great promise for the discovery of effective treatments for the core symptoms of autism spectrum disorders. Crawley and colleagues review the behavioural assays that are most relevant to the symptoms of human autism, along with the essential control measures.

In this comprehensive Review, Collingridge and colleagues describe the mechanisms underlying the induction and expression of various forms of long-term depression (LTD), and discuss the role of LTD in learning and memory as well as in various pathological processes.