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Activation of GIRK channels decreases the excitability of neurons. Lüscher and Slesinger discuss the subunit composition and function of GIRK channels in several brain regions and the possible role of GIRK channel dysfunction in neurological diseases such as epilepsy, Down's syndrome and drug addiction.
Jan and Jan discuss various mechanisms by which neurons acquire their type-specific dendrite morphology. These have largely emerged from studies inDrosophila melanogaster, but are broadly applicable to vertebrates. The possible contribution of defects in dendrite morphogenesis to mental disorders such as autism is also considered.
Emerging data suggest that small regulatory RNAs regulate stem cell self-renewal and neuronal fate specification. Li and Jin review the mechanisms through which this can be achieved and the implications for vertebrate and invertebrate neurogenesis.
The function of adult hippocampal neurogenesis is incompletely understood. Gage and colleagues describe the regulation and maturation of adult-born hippocampal neurons and review behavioural and computational modelling studies that indicate how adult-born neurons might contribute to hippocampus-dependent learning and memory.
Pulvermüller and Fadiga address the much discussed question of whether speech comprehension depends on activation of cortical motor areas. Reviewing data from neuroimaging, brain stimulation, lesion and computational studies, they conclude that action and perception circuits have interdependent roles in language comprehension.
Epidemiological and pathological evidence points to a link between traumatic brain injury and an increased risk of developing Alzheimer's disease in later life. Smith and colleagues consider the mechanisms underlying this link, with a focus on axonal injury and amyloid-β accumulation after injury.