Research articles

This study finds that reducing the amount of slow-wave sleep results in worse performance on a subsequent memory test and reduced encoding-related hippocampal fMRI activation. This happens even though the total amount of sleep was unaffected, suggesting that hippocampus-dependent memory is particularly affected by shallow sleep.

The authors use chronic in vivo imaging to study pyramidal neurons before and after deletion of the tumor suppressor gene Pten in mature neurons of the mouse cortex. They find that Pten/mTOR signaling only regulates growth of layer 2/3 apical dendrites.

The primary sensory areas are generally thought to be mapped according to the organizational structure of the sensory input; retinotopic, somatotopic, cochleotopic and even coarse chemotopic maps have all been identified in the brain. Optical imaging of the olfactory bulb now reveals that there is no fine-scale chemotopic map in the rodent olfactory bulb.

cAMP response element–binding protein (CREB) is a key regulator of the nucleus accumbens shell function in animals' responses to emotional stimuli. The present study demonstrates that passive stress in the form of social isolation induces anhedonia and depression-like symptoms that are mediated by CREB activity and neuronal excitability.

ProBDNF can have drastic effects on synaptic function that are quite different from those of mature BDNF. It is, however, controversial whether proBDNF is ever released in amounts that are sufficient to affect normal synaptic plasticity. Here, Yang and colleagues have detected the release of proBDNF from hippocampal neurons using newly developed knock-in mice and antibodies.

Fate-mapping the cells that express the homeodomain transcription factor Dbx1 in the developing mouse brain, this study finds that the preoptic area is a previously unknown source of inhibitory amygdala neurons. In contrast, excitatory amygdala neurons are shown to develop from Dbx1-positive cells in the ventral pallium.

This work shows that the transcriptional modulator and tumor suppressor Pml functions in embryonic nestin-positive cortical progenitor cells to regulate protein phosphatase 1α, leading to dephosphorylation of pRb, reduction of mitosis and increased neurogenesis.

The authors show that individual sensorimotor neurons in freely behaving swamp sparrows exhibit categorical responses to features of their songs. The neuronal response boundary predicts the categorical perceptual boundary that was measured in field studies of the same sparrow population, but not the perceptual boundary in populations that learn different song dialects.

The authors report that rats that were withdrawn from cocaine self-administration had an in vivo deficit in their ability to develop long-term potentiation and depression in the nucleus accumbens core following prefrontal cortex stimulation. N-acetylcysteine, a drug that prevents relapse, restored the ability to induce plasticity.

The function of Synaptotagmin IV (Syt IV) in vesicle exocytosis and neurotransmitter release is debated, as Syt IV does not bind calcium. Here, Zhang et al. show that Syt IV localizes to the vesicles of neuropeptide-secreting nerve terminals in the posterior pituitary and regulates the kinetics of calcium-triggered exocytosis.

Cheng and colleagues propose a mechanism for amyloid-β toxicity that may have relevance for Alzheimer's disease. They show that Aβ1–42 induces expression of collagen VI and that collagen VI protects against Aβ toxicity in cultured neurons.

The floor plate is not usually a neurogenic structure, but in the embryonic midbrain, dopaminergic neurons do develop from floor plate. This study shows that the high levels of Shh that are present in the floor plate generally suppress neurogenesis and that for neurons to be generated, Shh must be downregulated by Wnt signaling in the midbrain.