Addiction

Insulin signaling in the nervous system regulates ethanol intoxication in Drosophila melanogaster. Corl, A. B. et al. Nature Neurosci. 8, 18–19 (2005)

The fruitfly is a popular model for studying the effects of alcohol intoxication, because many of the molecular mechanisms that underlie ethanol-induced behaviour are conserved between flies and vertebrates. In this report, Corl et al. uncover a role for insulin signalling in the response to ethanol intake in Drosophila melanogaster. They show that flies become more sensitive to ethanol intoxication if the function of insulin-producing cells is impaired or if the insulin-receptor signalling pathway is disrupted.

Gene expression

Mouse brain organization revealed through direct genome-scale TF expression analysis. Gray, P. A. et al. Science 306, 2255–2257 (2004)

Transcription factors have important roles in many aspects of brain development, and Gray et al. used in situ hybridization to map the expression of more than 1,000 transcription factor-encoding genes in the developing mouse brain. Their screen identified an array of new markers for various brain regions and cell types, and the data are being compiled into a searchable atlas of transcription factor expression during brain development.

Synaptic plasticity

Dendritic spine heterogeneity determines afferent-specific Hebbian plasticity in the amygdala. Humeau, Y. et al. Neuron 45, 119–131 (2005)

In laminar brain structures, dendritic arbors tend to be compartmentalized, so that afferents from different sources are spatially segregated within the arbor. However, Humeau et al. show that in the lateral nucleus of the amygdala (LA), which is not overtly laminar, cortical and thalamic afferents intermingle on the same dendritic branch. Moreover, spines that are postsynaptic to these two types of afferent have distinct morphological and molecular characteristics. These findings imply that synaptic plasticity in LA neurons is controlled locally on a spine-by-spine basis.

Neural induction

Neural induction in Xenopus requires early FGF signaling in addition to BMP inhibition. Delaune, E. et al. Development 132, 299–310 (2005)

Classical experiments using explants of embryonic Xenopus ectoderm led to the hypothesis that neural induction depends on the inhibition of bone morphogenetic protein (BMP) signalling. Recently, this model was challenged by findings in avian embryos, which indicated a crucial role for fibroblast growth factor (FGF) signalling. To try to reconcile this discrepancy, Delaune et al. studied neural induction in whole frog embryos, and they provide evidence that induction of the nervous system requires FGF signalling at the pre-gastrula stage, as well as BMP inhibition.