Articles in 2009

The authors found considerable preparation-to-preparation variability in the strength of two identified synapses, the amplitude of a modulator-evoked current and the expression of six ion channel genes in the pyloric circuit of the crab stomatogastric ganglion. These parameters correlated with circuit performance. Circuits produced similar outputs because of compensatory and coordinated changes among the parameters.

Here, Chen et al. describe the role of the G protein–coupled receptor GPR17 in oligodendrocytes and show that it acts as a negative regulator of oligodendrocyte maturation and myelination.

Smad-interacting protein 1 (Sip1) is a transcriptional repressor that acts in the TGF-β signaling pathway. This study finds that Sip1 is involved in a feedback signaling mechanism in which newly generated postmitotic cells in neocortical layers instruct progenitor cells for proper cell-fate switch and proliferation.

Although previous work has shown that extensive training in the complex visuo-motor skills involved in juggling results in adult gray-matter changes, it is unclear whether such practice can produce similar changes in adult white matter. This paper now uses diffusion tensor imaging to demonstrate structural white-matter changes when adults practice juggling.

The main function of the α₂δ-3 calcium channel subunit is thought to be facilitation of the pore-forming subunit delivery to presynaptic terminals. Kurshan et al. now show that this subunit has other, independent synaptogenic functions and that it is important for shaping the architecture of the synapse.

The authors show that the LIM homeodomain transcription factor Lhx2 is responsible for the fate decision of cortical progenitors to generate neocortex or olfactory cortex. Conditional deletion of Lhx2 in telencephalic progenitors refated them to generate three-layer cortex resembling olfactory cortex, rather than lateral neocortex.

Using endogenous circadian oscillators, Drosophila can anticipate diurnal light on/off transition and behave accordingly. Here, the authors show that the fly evening oscillator circuit can synchronize to light cycle through the visual system and the molecular components of morning oscillator.

A feeding leech ignores incoming stimuli that would normally cause an avoidance response. This study found that synaptic transmission from mechanosensory neurons to postsynaptic partners was reduced in feeding leeches. This presynaptic depression by feeding could be mimicked by serotonin and was antagonized by a blocker of an unusual serotonin-gated chloride channel.

The nucleus basalis is thought to regulate arousal and attention via release of acetylcholine in the cortex. Here the authors report that nucleus basalis stimulation in rats results in a decorrelation between visual cortical neurons as a result of activation of cortical muscarinic receptors and an increase in the reliability of responses to natural scenes as a result of more distributed changes along the visual pathway.

Activity in the frontal eye fields (FEF) is important for visuospatial processing and is thought to code information in retinal coordinates. This fMRI study finds FEF activity even for auditory locations behind the head, suggesting that extra-retinal space is also coded in this area.

The authors report the conditional deletion of the alpha and beta forms of glycogen synthase kinase 3 (GSK-3) in mouse neural progenitors. This deletion is associated with dysregulations in β-catenin, Sonic Hedgehog, Notch and fibroblast growth factor signaling pathways and leads to markedly increased proliferation of neural progenitors.

A recent report by the National Academy of Science makes recommendations for ensuring the integrity of research data. Critically, it also highlights the urgent issues regarding the preservation of large datasets.

Laminar neuronal density varies between cortical areas; thus, the developmental specification of areas and layers needs to be coordinated. AP2γ turns out to be an important regulator of upper layer development in occipital cortex.

During the day, certain retinal ganglion cells respond specifically to dark, approaching stimuli. A study finds that the retinal circuit that gives rise to this response makes use of an amacrine cell that was previously known for its role in night vision circuitry, demonstrating that some neurons lead double lives.

Fusion of synaptic vesicles upon calcium influx requires precise localization of voltage-gated calcium channels. A new study identifies a previously uncharacterized protein that mediates trafficking of Ca_V2 calcium channels in C. elegans.

A study in this issue found that suppressing expression of TRPM7 in hippocampal CA1 neurons conferred resistance to ischemic cell death, preserved cell function and prevented ischemia-induced deficits in memory.

Recent human imaging work has expanded the view of amygdala function beyond early findings in animals, but two studies of an individual with bilateral amygdala damage now suggest that we should be thinking even more broadly.

Tonic pain, a chief clinical problem, is difficult to study in rodent models that measure threshold changes of evoked reactions to acutely applied stimuli. These authors used conditioned place preference to assess tonic pain in rats and measure the efficacy of agents that relieve it.

The instinctual attachment of young animals to their mothers is crucial for survival. Demonstrating the overriding importance of attachment, very young rat pups learn to prefer an odor coupled to electrical shock if the mother is present. This paper shows that low amygdalar dopamine signaling in very young pups is essential for their paradoxical response to odor/shock conditioning.