Review Articles in 2009

In addition to their roles in nervous system development, Wnts participate in synaptic maintenance and function and in adult neurogenesis. Here, Inestrosa and Arenas review the latest research on the functions of Wnt signalling in the adult nervous system and potential therapeutic implications.

Marr–Albus models of cerebellar function have been influential but cannot completely explain recent experimental findings. Dean and colleagues show that these recent data are congruent with the computational principles of adaptive-filter operations, suggesting that the cerebellum might act as an adaptive filter.

Visual perceptual learning (VPL) underlies long-term improvements in performance in perceptual tasks. Watanabe and colleagues discuss current ideas about the processing and neural substrates of VPL that may shed light on mechanisms of neural plasticity.

Spontaneous, patterned activity occurs in many developing neural circuits and is important for the establishment of neuronal connections. Blankenship and Feller describe the similarities and differences in the generation, regulation and robustness of this activity in different neural circuits.

In recent years, a role has been proposed for the neurotrophin receptor tyrosine kinase TrkB in synaptic plasticity, learning and memory. Liliana Minichiello discusses the signalling pathways downstream of TrkB activation that might contribute to this function.

The remarkable functional and structural changes that take place in the brains of blind and deaf individuals following sensory loss enable them to operate effectively in their environment. Here the authors discuss the current understanding of the mechanisms that underlie this crossmodal neuroplasticity and its implications for rehabilitation.

Primary visual cortex (V1) is often used as a prime example of cortical plasticity both during development and in adulthood. In this provocative Review, Wandell and Smirnakis reassess the literature and discuss the evidence for and against plasticity in adult V1.

Evidence suggests that a time-limited window of plasticity exists following a stroke, during which most behavioural recovery occurs. Murphy and Corbett describe advances in our understanding of plasticity and recovery after stroke and highlight parallels with developmental plasticity.

MicroRNAs are emerging as key modulators of post-transcriptional gene regulation in the synaptodendritic compartment. Here, Schratt reviews recent studies showing that neural activity controls microRNA transcription, subcellular localization, processing and function, and discusses the relevance of microRNAs for synapse development and plasticity.

An important role for zinc homeostasis in brain function has recently emerged. Sensi and colleagues review the evidence pointing to the physiological role of zinc in the regulation of synaptic excitability and to its pathophysiological role in brain trauma and Alzheimer's disease.

Vann and colleagues review anatomical, lesion and imaging studies suggesting that the retrosplenial cortex is involved in navigation and memory. They propose that it achieves this function through a key role in scene construction by translating between different perspectives of the environment.

What allows some species, but not others, to regenerate their nervous system? In this Review, the authors compare CNS regeneration among vertebrates looking for clues that might explain how this ability might have emerged or been restricted through evolution.

Focusing on mammalian species, Pasko Rakic uses evo–devo studies to model how gene mutations may have affected neuron number and neuronal migration, which in turn may have contributed to the species-specific expansion and elaboration of the cerebral cortex.

Brain activation during REM sleep and dreaming resembles that during waking, but what is the meaning of this activity? Allan Hobson discusses the emergence of REM sleep states during evolution and development and proposes that the activity constitutes a protoconscious state.

To reach their final destinations within the nervous system, glial cells must often migrate over long distances. Klämbt discusses the mechanisms of glial cell migration, highlighting common mechanisms and differences between vertebrate and invertebrate glial migration.

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.

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.