Volume 13 Issue 6, June 2010

A study in this issue finds that laboratory strains of male mice can recognize their offspring as adults if given the chance to interact with infant pups. This recognition requires prolactin-mediated adult neurogenesis in the male parent's olfactory bulb and hippocampus.

Cilia are increasingly appreciated regulators of brain homeostasis. Several recent studies examine the cellular and molecular mechanisms of their biogenesis and orientation in ependymal cells.

New work identifies a neurogenic progenitor population in the developing human and ferret cortex that may have contributed substantially to the evolution of cortical expansion and folding in higher mammals.

Combining cell group specific gene expression patterns with recent technologies has provided insights into brain circuitry. A new resource may make it possible for those studying the hypothalamus to use these techniques as well.

A newly discovered population of glutamatergic brainstem neurons that can be activated by muscarinic agonists augments transmission from the mesencephalic locomotor region to reticulospinal neurons in the locomotor pathway.

The authors report that the type 5 G protein beta subunit forms a complex with the protein RGS7 and that these complexes regulate the coupling of G protein–gated potassium channels to GABA_B receptors in neurons.

The authors report that persistent, gene-specific hypermethylation is induced by associative learning and that inhibition of methylation long after learning disrupts remote memory. This suggests that DNA methylation may be a mechanism for preserving long-lasting memories.

Multivariate pattern analysis of auditory cortex functional magnetic resonance imaging data can differentiate among sounds implied by entirely silent visual stimuli. This adds to the evidence suggesting that early sensory cortex activity reflects perceptual experience rather than sensory stimulation alone.

Adolescents are thought to be hypersensitive to rewards. Using model-based fMRI, the authors identify elevated reward prediction error signals in the striatum during adolescence, which could contribute to the increased reward-seeking behavior seen during this stage of development.

Using live imaging of progenitors in zebrafish embryo, the authors find that asymmetric inheritance of an apical domain marker, Par3, is strongly correlated with asymmetric daughter fates. Furthermore, the daughter cell that is destined to become a neuron is the more apical of the two daughters.

The amygdala contains neurons that express OTP, a homeodomain transcription factor that is otherwise limited to diencephalon. Here, the authors find that these cells are indeed generated in diencephalic ventricular zone and that they then migrate tangentially into telencephalon to colonize certain nuclei of the amygdala.

This work identifies a population of precursors in the outer subventricular zone (SVZ) of developing human and ferret brains. The cells share some properties with the radial glia of the ventricular zone, and, in contrast with previously identified progenitors in SVZ, undergo several asymmetric neurogenic divisions. These progenitors may contribute to the development of gyrated cortices in higher mammals.

Tissir et al. find that atypical cadherins Celsr2 and 3 and planar cell polarity signaling are required for the proper development and function of cilia in ependymal cells, and that their loss of function markedly impairs cerebrospinal fluid circulation.

TRPV1 is a member of the family of temperature-activated transient receptor potential ion channels. This study identifies mutations in the outer pore region of TRPV1 that impair temperature activation by ablating long channel openings.

The mechanism of light sensation in the worm C. elegans has been unclear. Liu and colleagues describe a G protein–dependent signaling cascade for light transduction that is similar to the mechanism for taste sensation.

In mice, social odors activate vomeronasal sensory neurons (VSNs); a large percentage of VSNs detect sulfated steroids. Here, the authors find that information about these molecules is conveyed through just a few sensory 'processing streams'. Downstream responses of accessory olfactory bulb neurons suggest distinct integratory roles: most relay a VSN pattern, although a substantial minority integrate across processing streams.

This study identifies a population of cells in lamprey brainstem that are activated by cholinergic input from the mesencephalic locomotor region and in turn excite the reticulospinal neurons that drive spinal motor neurons, representing a previously unrecognized feedforward circuit.

Local circuit connectivity patterns have been described as being either layer specific or projection class specific. Here, Anderson et al. find that the main excitatory pathway in mouse motor cortex, from layer 2/3 to layer 5, is fractionated on the basis of both neuronal sublayer position and projection class.

This study reports that the induction of the transcription factor ΔFosB is critical for mice to show resilience to the effects of chronic social defeat stress and for antidepressant responses in susceptible mice. ΔFosB acts to promote resilience by the induction of the GluR2 AMPA glutamate subunit, which decreases the responsiveness of nucleus accumbens neurons to glutamate.

This study reports that male laboratory mice can recognize their adult offspring if they are allowed postnatal interaction with their pups. This process is dependent on prolactin enhancement of neurogenesis in the paternal olfactory bulb and hippocampus and the adult-born paternal olfactory neurons show preferential activation towards offspring odors.

Understanding the role of astrocytic calcium signals has been hindered by our inability to measure calcium in small volume compartments. Here, the authors develop a technique to do this by modifying the genetically encoded calcium sensor GCaMP2 to ensure greater expression near the membrane.

This Resource chronicles dynamic gene expression patterns in the developing hypothalamus from embryonic day 10.5 through maturity. The authors find that Shh must be expressed in the hypothalamic basal plate for differentiation of the anterior and tuberal hypothalamic nuclei.