Articles in 2009

Nardilysin (NRDc) enhances the shedding of ectodomains from neuronal membrane proteins. The null mutant described here reveals that nardilysin is necessary for myelination in both central and peripheral nervous system.

Major histocompatibility complex peptides function as olfactory cues for vomeronasal sensory neurons (VSNs) in the mammalian nose. Here, the authors report that individual VSNs expressing the receptor gene V2r1b have broad peptide responsiveness, but sufficient specificity to distinguish peptides differing by a single amino acid residue. Furthermore, they find that targeted disruption of V2r1b eliminates the VSN peptide response.

Even without the symptoms of Alzheimer's disease, normal brain releases a small amount of amyloid-β peptide (Aβ). Abramov and colleagues now show that endogenous Aβ that is produced and released from presynaptic terminals can alter synaptic transmission and short-term plasticity.

Previous work has suggested that visual attention improves behavioral performance by increasing the firing rates of individual sensory neurons. Recording from populations of neurons in monkey visual area V4, this study finds that most of the attentional improvement in the population signal results from decreases in interneuronal correlations.

Nakazawa and colleagues describe a mouse strain in which the NR1 subunit of the NMDA receptor is selectively eliminated in cortical and hippocampal interneurons in early postnatal development. These mice have several behavioral deficits that are consistent with the theory that GABAergic dysfunction contributes to the pathology of several psychiatric disorders, including schizophrenia.

In Drosophila, the connections between olfactory receptor neurons and projection neurons are highly specific. Here, the authors report that two leucine-rich repeat transmembrane proteins (Capricious and Tartan) serve as a mechanism for projection neuron dendrite targeting in the olfactory map.

During development of the peripheral ganglia, 50% of neurons die by apoptosis. This study finds that satellite glial cell precursors clear these neuronal corpses in developing dorsal root ganglia and identifies some of the molecular components involved in this phagocytosis.

Notch signaling is essential for the maintenance of adult neural stem cells in vivo. Here, Andreu-Agulló and colleagues show that PEDF, released from endothelial cells, enhances Notch signaling in the mouse subependymal zone by inactivating a repressor of Notch target genes.

Severe stress in early childhood can increase an individual's vulnerability to depression later in life. This study found that early-life stress in mice resulted in persistent elevation of the stress hormone arginine vasopressin (AVP), which was caused by persistent hypomethylation of CpG islands in the Avp promoter in the hypothalamus.

Systematically monitoring the activities of various cortical pyramidal neurons and interneurons during different stages of locomotion, the authors characterize differential firing activities of motor cortex microcircuitry in behaving, head-restraint rats that were trained to push, pull or hold a lever for reward.

The cortex is sensitive to weak stimuli, but also responds to stronger inputs without saturating. In this study, Scanziani and colleagues find some of the circuits that enable neuronal populations to respond to a wide range of input strengths.

Neural stem cells in the adult mouse SVZ are thought to only generate GABAergic olfactory bulb interneurons. This study reports that a dorsal region of the adult SVZ gives rise to a glutamatergic type of olfactory bulb neurons. These newborn glutamatergic neurons can be diverted to migrate into the cortex towards an injury, possibly contributing to repair.

Certain Drosophila dendrites undergo major remodeling during metamorphosis. This study shows that the severing of larval dendrites, which is the first step of remodeling, depends on the upregulation of the cytoskeleton-binding protein Mical by the transcription factor Sox14.

Monkeys were trained to switch rapidly between two category boundaries when classifying the speed of a moving dot pattern. Neurons in the frontal eye field changed their activity when the boundary changed and a subset of these neurons were used to classify the stimuli nearly as accurately as the monkeys' behavioral performance.

This study shows that the kinase Mst3b is required cell-autonomously for axon regeneration of both retinal ganglion cells and peripheral sensory neurons in vitro and in vivo.

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.

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.