Research articles

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.

Studying a patient with selective damage to the insular and anterior cingulate cortex, the current study finds that these regions are not necessary for interoceptive awareness of one's own heartbeat, but the primary somatosensory cortex is required for such self-awareness.

Although numerous in vivo studies have suggested that hippocampal theta oscillations are generated by the extrinsic medial septal input, theoretical studies have suggested that the hippocampus has the minimal feedback circuitry necessary to intrinsically generate its own theta rhythm. Here, Goutagny et al. directly demonstrate such oscillation independently of external inputs.

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.

Contrary to previous findings, this study finds that ablation of microglia, the resident macrophages of the brain, does not affect amyloid plaque or neuritic pathology in two mouse models of Alzheimer's disease.

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.