Reviews & Analysis

To enable the complex neural circuitry found in vertebrates, many axons undergo extensive branching. Here, Kalil and Dent review the roles of extracellular cues, intracellular signalling pathways, cytoskeletal dynamics and neuronal activity in axon branching and terminal arbor formation in the vertebrate CNS.

Itch — the sensation that induces the desire to scratch — results from activity in a subset of nociceptors, all of which also respond to painful stimuli. LaMotte and colleagues describe the studies that have begun to pinpoint the molecular transducers and neural pathways that transmit itch and the coding mechanisms that distinguish it from pain.

After nerve injury, signals from the lesion site must reach the nucleus in order to initiate the transcriptional responses required for regeneration. In this Review, Rishal and Fainzilber describe recent developments in our understanding of the molecular basis of this retrograde injury signalling system.

During development, individual neural progenitors give rise to a series of distinct types of neural progeny that are produced in a specific temporal order. Kohwi and Doe discuss how temporal neural patterning is dictated by extrinsic and intrinsic cues known as temporal-identity factors, as well as by changes in progenitor competence in response to these factors.

Newly generated glutamatergic synapses lack functional AMPA receptor-mediated transmission. Depending on the type of activity that these newborn AMPA-silent synapses are exposed to, they are eventually either eliminated or stabilized. Hanseet al. review recent studies on the abnormal generation of AMPA-silent synapses and on premature or delayed unsilencing that highlight their role in brain pathology.

Increasing evidence of the high incidence of mild cognitive impairment and psychomotor slowing in patients with chronic liver disease has highlighted the need to treat the neurological alterations of these patients. In this article, Felipo reviews the latest studies aimed at understanding how liver failure affects brain function and potential ways to ameliorate these effects.

Local field potentials (LFPs) provide a wealth of information about synaptic processing in cortical populations but are difficult to interpret. Einevoll and colleagues consider the neural origin of cortical LFPs and discuss LFP modelling and analysis methods that can improve the interpretation of LFP data.

Understanding how each of the many diverse subtypes of neurons that make up the cortex are specified during development presents a continuing challenge for developmental neurobiologists. Macklis and colleagues describe recent advances in our understanding of the specification of cortical projection neuron subtype and area identity.

Children with conduct disorder show persistent aggressive or antisocial behaviour and, in some cases, psychopathic traits. In this Review, Blair describes the neural and cognitive mechanisms — and their interaction with environmental factors — that underlie psychopathic behaviour.

In order to make sense of the multitude of acoustic stimuli that surround us in our daily lives, the auditory system needs to be able to assign different sounds to specific sources within the 'auditory scene'. Bizley and Cohen describe how auditory information processing in the cortex categorizes and groups different sounds into 'auditory objects'.

Thefruitless (fru) gene is a crucial regulator of male courtship behaviour. In this Review, Yamamoto and Koganezawa discuss and integrate findings from molecular, cellular and behavioural studies of fruto provide an understanding of how a single gene can organize such an elaborate behaviour.

In this Review, Pouladi and colleagues critically examine the strengths and limitations of the currently available animal models of Huntington's disease. By doing so, they aim to facilitate animal model selection in future studies of this progressive neurodegenerative disorder.

Recent evidence suggests that mood disorders are associated with altered reward function. Russo and Nestler review studies that have shown alterations in the brain reward circuitry in patients with, and animal models of, depression, and discuss the cellular and molecular underpinnings of these alterations.

Activity-dependent changes in neuronal gene expression require a means of synapse-to-nucleus signalling, and changes in nuclear calcium concentration provide a major route for such communication. Bading discusses how nuclear calcium signals are induced by synaptic activity and describes their role as regulators of gene expression in neuroadaptations.

Many cases of Parkinson's disease (PD) are characterized by not only deficits in movement but also cognitive dysfunction, which can develop into dementia. Here, Irwinet al. review the complex connections between the neuropathological aetiologies that underlie the cognitive deficits associated with PD.

Hypnosis is used in treatment contexts and, recently, also as an investigative tool in cognitive neuroscience. Oakley and Halligan review the potential for hypnosis to provide insights into brain mechanisms involved in attention, motor control, pain perception, beliefs and volition and also to produce informative analogues of clinical conditions.

Correct functioning of the brain requires stability as well as plasticity of neural circuits, and loss of stability is associated with numerous neurological disorders. In this Review, Koleske discusses recent insights into the molecular mechanisms that govern long-term dendrite and synapse stabilization.

Planar cell polarity (PCP) is regulated by a core set of conserved genes. Tissir and Goffinet describe the emerging roles of these PCP genes in various developmental processes in the nervous system, including neural tube closure, neuronal migration and axon guidance.

Intricate mechanisms regulate iron homeostasis in the CNS. In this Review, Rouault considers the role of brain iron accumulation in several common neurodegenerative disorders and discusses 'neurodegeneration with brain iron accumulation' diseases that are associated with specific genetic mutations.

In order to anticipate and prepare effectively for future experiences, the brain must cope with the inherent uncertainty of future events. In this Review, Grupe and Nitschke show how alterations in the processes by which the brain deals with future uncertainty may contribute to the development of pathological anxiety.