Volume 15 Issue 9, September 2012

NG2⁺ glia, the progenitors of myelinating oligodendrocytes, receive synaptic input, but why? A study now finds that sensory input regulates the proliferation and location of NG2⁺ glia in the mouse somatosensory cortex barrel field.

Phasic bursting of dopaminergic neurons influences many behaviors. A study now finds that ATP-sensitive potassium channels mediate bursting in dopaminergic neurons of the medial substantia nigra and affect novelty-induced exploration.

A report in this issue suggests that inhibiting histone deacetylase 2 (HDAC2) could be therapeutic in schizophrenia. Targeting chromatin remodeling in adults to treat a chronic brain disorder is not, however, likely to be easy.

Animals often must vie with others for scarce resources, such as food, water and mates. Deciding when to engage and when to avoid such contests might critically depend on the activity of anterior cingulate cortex neurons.

This review compares and contrasts decision-making processes in adults versus adolescents, to highlight how adolescent decision-making is particularly susceptible to modulation by emotional and social factors (such as peer pressure).

NG2 proteoglycan⁺ cells are neural and oligodendrocyte progenitors, and NG2⁺ cells in the developing barrel cortex receive glutamatergic thalamocortical inputs. Here, the authors show that NG2⁺ cells are primarily localized in barrel septa and that sensory deprivation induces NG2⁺ cell proliferation and differential localization in and around the barrels.

The authors show that spontaneous transmission from inhibitory synapses, in contrast with excitatory synapses, is triggered by voltage-dependent calcium channel activity. In addition, they find that spontaneous GABA release involves coincident opening of multiple closely packed calcium channels.

The identity of the mechanosensitive channel responsible for sound transduction in the ear has remained elusive. Here the authors show, using interferometry, that the gating compliance of the fly's hearing organ is disrupted after deletion of TRPN1, identifying this channel as the sound transducer and/or its gating springs.

This study describes how interactions between DOCK7 and TACC3 are key to the switch from proliferation to differentiation in developing radial glial progenitor cells (RGCs). DOCK7 exerts its effects via interactions with the centrosome-associated protein TACC3, and these interactions are likely to modulate the RGCs' apically directed interkinetic nuclear migration.

In this study, the authors show that, during the development of the enteric nervous system, a subset of enteric neural crest cells migrate from midgut across the mesentery to colonize caudal hindgut. This trans-mesenteric migration requires GDNF and GFRα1 signaling.

The Drosophila proteins Neuroligin (Nlg1) and Neurexin (Nrx-1) form a trans-synaptic complex that regulates synapse formation at the neuromuscular junction. Here the authors show that Syd-1, also known to regulate active zone formation, interacts with presynaptic Nrx-1, promoting synaptic clustering and immobilization of Nrx-1, and subsequent glutamate receptor incorporation.

Here the authors show that the binding of amyloid-β (Aβ) oligomers to cellular prion protein (PrPc) activates Fyn kinase. Aβ stimulation of PrPc/Fyn signaling drives phosphorylation of the NR2B subunit of NMDA receptors, with a subsequent loss of receptor surface expression and dendritic spines.

In this study, the authors show that two K⁺ channels, SK3 and GIRK, are important for the pheromone-induced activation of olfactory neurons in the vomeronasal organ (VNO). In addition, they show that K⁺ ion concentrations are maintained at high levels in the VNO lumen, permitting inward K⁺ flux through these channels.

The authors show that chronic treatment with antipsychotic drugs decreases expression of mGlu2 and histone acetylation at its promoter in frontal cortex. This is mediated through 5-HT2A receptor–dependent upregulation of HDAC2. HDAC inhibitors prevent this decrease in mGluR2, augmenting the behavioral effects of antipsychotics.

The authors report that endogenous myocyte enhance factor 2 (MEF2) levels affect spatial and fear memory formation in adult mice. MEF2-induced memory disruption was rescued by interfering with AMPA receptor endocytosis.

Using juxtacellular recording and labeling of hippocampal interneurons in drug-free and behaving rats, the authors show that parvalbumin-expressing basket interneurons fire in a behavioral state–dependent manner, in contrast with neuropeptide Y– and nitiric oxide synthase–expressing ivy cells.

The authors show that K-ATP channels in dopamine (DA) neurons of the medial substantia nigra (m-SN) enable burst firing in vitro and in vivo. Silencing K-ATP channel activity in m-SN DA neurons decreases novelty-dependent exploratory behavior in mice.

In tasks involving goal-directed action selection, striatal neural activity has been shown to represent the value of competing actions. Here the authors show that transient optogenetic stimulation of dorsal striatal D1 and D2 receptor–expressing neurons during decision-making biases choices in a way that mimics an additive change in action value.

The anterior cingulate cortex is known to be involved in determining cost versus benefit, but, by recording from rats choosing to engage in competition with another rat for limited rewards, the authors found that this area is also involved in competitive effort.

Using simultaneous electrophysiological and optical imaging, this study finds that it is the linear summation of stimulus-independent trial-related and stimulus-dependent components that yield the signal seen in neuroimaging studies. However, the trial-related component, which does not correlate with neural spiking or LFPs, can account for over half of the neuroimaging signal, suggesting that it is crucial to take this component into account when interpreting neuroimaging studies.

Humans and other animals can learn from errors of other individuals. Here, using two paired monkeys monitoring each other's action for their own action selection, the authors identify neurons in the medial frontal cortex (MFC) that have activity correlated with another's errors. This suggests that the MFC could contribute to monitoring others' mistakes.

The olfactory system is vulnerable to sensory deprivation owing to the prevalence of rhinosinusitis, but how the brain encodes and maintains odor information under such circumstances remains poorly understood. Using fMRI, the authors find evidence for transient changes in olfactory brain regions that sustain odor perception following disrupted sensory input.