Articles in 2010

This study finds that mice's biological clocks are permanently influenced by the seasonal photoperiod at and after birth. In mice raised under summer-like light periods, rhythmic gene expression in the suprachiasmatic nucleus was tightly correlated with lights-off under both summer- and winter-like cycles. In 'winter-born' mice, these rhythms were tightly correlated only under winter-like light cycles.

This study reports that the size of the primary visual cortex correlates negatively with the magnitude of two common visual illusions. The size of primary visual cortex may therefore modulate conscious visual experience.

The roles of striatopallidal (indirect) and striatonigral (direct) pathway neurons in regulating behavior is of great interest. Ferguson et al. selectively and transiently disrupt either one pathway or the other. They find that disrupting striatopallidal neuronal activity facilitated behavioral sensitization, whereas disrupting striatonigral neurons impaired its persistence.

Ca_v1.3 calcium channels are critical for neurotransmitter release in auditory hair cells and cardiac pacemaking. The authors identified a mutation in CACNA1D, which encodes the pore-forming α1-subunit of Ca_v1.3, in deaf humans. These individuals also exhibited bradycardia. The insertion of a glycine residue near the pore resulted in nonconducting channels.

During Drosophila metamorphosis, the γ axons of mushroom bodies are pruned and regrow into their adult morphology. The pruning process requires the ecdysone receptor EcR-B1. The authors find antagonistic transcriptional regulation of EcR-B1 by two closely related nuclear receptors, Ftz-f1 and Hr39.

The authors report a transcriptional profile of the discrete stages of spontaneous remyelination following toxin-induced focal demyelination in rats. They find an enrichment of retinoid X receptor (RXR) signaling pathways over the course of remyelination and show that RXR activation stimulates oligodendrocyte differentiation to enhance remyelination.

Motoneuron recruitment is thought to occur in an orderly matter to generate the appropriate movements. Here, the authors find that recruitment threshold is not dictated by input resistance, as was previously believed, but by a combination of biophysical properties and the strength of the synaptic currents.

A study in this issue reveals gene expression differences between neurons that do, and those that do not, show recovery-associated growth after stroke. The differentially expressed genes may provide potential therapeutic targets.

Two studies in this issue find that postsynaptic TRPV1 receptors affect AMPA receptor endocytosis to mediate anandamide-induced long-term depression in the hippocampus and nucleus accumbens.

Optogenetic stimulation of the locus coeruleus noradrenergic neurons can increase wakefulness, and high-frequency stimulation decreases noradrenaline levels and produces loss of muscle tone similar to that seen in cataplexy.

There is a public perception that connectomics will translate directly into insights for disease. It is essential that scientists and funding institutions avoid misrepresentation and accurately communicate the scope of their work.

Tiny gaze shifts, or microsaccades, have little function in the eye movement control system and were once thought to be suppressed during fine spatial judgements. A new study suggests that they are important for finely guided visuomotor tasks and may actively contribute to the acquisition of spatial information in the same way as do larger saccades.

Synaptic vesicles release neurotransmitters both at rest and when stimulated. Wilhelm et al. use a variety of assays to show that the same vesicles participate in both active and spontaneous release.

Whether the same pool of synaptic vesicles participates in both spontaneous and activity-dependent release remains controversial. Using a combination of new and established probes, the authors find cross-depletion of spontaneously and activity-dependent pools, indicating that both types of release draw from a common pool.

The receptor sortilin has been implicated in pro-apoptotic signaling of proneurotrophins. In this study, the authors uncover another role for sortilin in neurotrophin signaling: it interacts with Trk family receptors to promote their anterograde transport to nerve endings, thereby enhancing neurotrophin-dependent cell survival.

Volitional control over object viewing improves subsequent memory for these objects in normal subjects. A comparison between subjects with and without hippocampal damage, as well as fMRI imaging during the task, suggest that the hippocampus is a key locus for changes during volitional versus passive object viewing.

Sensory adaptation is thought to improve perceptual discriminability of sensory stimuli. Using simultaneous recordings in aligned thalamic and cortical cells in the vibrissal pathway, the authors find evidence suggesting that adaptation of cortical signals is not apparent in the firing of individual thalamic neurons, but is reflected in thalamic synchrony.

Using a rat model of PD, the authors find a progressive decline in autonomous globus pallidus pacemaking. This loss was reversed by viral expression of the HCN channel. However, the motor disability induced by DA depletion was not reversed, suggesting that the loss of pacemaking was a consequence, not a cause, of key network pathophysiology.

The authors show that synaptic activation of group I metabotropic glutamate receptors in indirect, but not direct, pathway nucleus accumbens medium spiny neurons causes endocannabinoid production. This in turn triggers a form of long-term depression that is dependent on postsynaptic TRPV1 cation channels and endocytosis of AMPA receptors.

There are thought to be canonical patterns of connectivity between excitatory neurons of different layers within a column, but whether such patterns exist for inhibitory connectivity remained unclear. Here the authors identify stereotypical connectivity motifs across M1, V1 and S1, but find that their abundance varies among regions and cell types.