Cortico-cortical projections in mouse visual cortex are functionally target specific

Neurons in primary sensory cortex have diverse response properties, whereas higher cortical areas are specialized. Specific connectivity may be important for areal specialization, particularly in the mouse, where neighboring neurons are functionally diverse. To examine whether higher visual areas receive functionally specific input from primary visual cortex (V1), the author used two-photon calcium imaging to measure responses of axons from V1 arborizing in three areas with distinct spatial and temporal frequency preferences. they found that visual preferences of presynaptic boutons in each area were distinct and matched the average preferences of recipient neurons. This specificity could not be explained by organization within V1 and instead was due to both a greater density and greater response amplitude of functionally matched boutons. Projections from a single layer (layer 5) and from secondary visual cortex were also matched to their target areas. Thus, transmission of specific information to downstream targets may be a general feature of cortico-cortical communication.

Lindsey L Glickfeld, 

Nature Neuroscience (2013) doi:10.1038/nn.3300

In vivo reprogramming of circuit connectivity in postmitotic neocortical neurons

The molecular mechanisms that control how progenitors generate distinct subtypes of neurons, and how undifferentiated neurons acquire their specific identity during corticogenesis, are increasingly understood. However, whether postmitotic neurons can change their identity at late stages of differentiation remains unknown. To study this question, the authors developed an electrochemical in vivo gene delivery method to rapidly manipulate gene expression specifically in postmitotic neurons. Using this approach, they found that the molecular identity, morphology, physiology and functional input-output connectivity of layer 4 mouse spiny neurons could be specifically reprogrammed during the first postnatal week by ectopic expression of the layer 5B output neuron–specific transcription factor Fezf2. These findings reveal a high degree of plasticity in the identity of postmitotic neocortical neurons and provide a proof of principle for postnatal re-engineering of specific neural microcircuits in vivo.
Andres De la Rossa, et al.
Nature Neuroscience (2013) doi:10.1038/nn.3299

Dual origins of the mammalian accessory olfactory bulb revealed by an evolutionarily conserved migratory stream

The accessory olfactory bulb (AOB) is a critical olfactory structure that has been implicated in mediating social behavior. It receives input from the vomeronasal organ and projects to targets in the amygdaloid complex. Its anterior and posterior components (aAOB and pAOB) display molecular, connectional and functional segregation in processing reproductive and defensive and aggressive behaviors, respectively. We observed a dichotomy in the development of the projection neurons of the aAOB and pAOB in mice. We found that they had distinct sites of origin and that different regulatory molecules were required for their specification and migration. aAOB neurons arose locally in the rostral telencephalon, similar to main olfactory bulb neurons. In contrast, pAOB neurons arose caudally, from the neuroepithelium of the diencephalic-telencephalic boundary, from which they migrated rostrally to reach their destination. This unusual origin and migration is conserved in Xenopus, providing an insight into the origin of a key component of this system in evolution.

Dhananjay Huilgol, et al.
Nature Neuroscience (2013) doi:10.1038/nn.3297

New Information on Autism and Genetics

Research out of the George Washington University reveals another piece of the puzzle in a genetic developmental disorder that causes behavioral diseases such as autism.
"It tell us that in very early development, those with 22q11.2 deletion syndrome do not make enough cells in one case, and do not put the other cells in the right place. This occurs not because of some degenerative change, but because the mechanisms that make these cells and put them in the right place during the first step of development have gone awry due to mutation,"said LaMantia.

Science Daily - Jan. 3, 2013
T. M. Maynard, et.al.
A comprehensive analysis of 22q11 gene expression in the developing and adult brain. 

Proceedings of the National Academy of Sciences, 2003; 100 (24): 14433 DOI:10.1073/pnas.2235651100

The Immune System's Compact Genomic Counterpart

Much of the human genome derives from self-serving DNA strands known as transposons. These genetic gypsies often jump to new chromosome locations, sometimes disabling genes and even triggering cancer. For that reason, a specialized group of RNA molecules known as piRNAs are the superheroes of animal genomes. piRNAs team up with certain proteins to shackle transposons in animal germline cells, creating a molecular defense that scientists liken to an immune system for the genome.
Science 4 January 2013: vol. 339 no. 6115 25-27

Cancer-Specific Killer T Cells Created from Induced Pluripotent Stem Cells (iPSC)

Researchers from the RIKEN Research Centre for Allergy and Immunology in Japan report today that they have succeeded for the first time in creating cancer-specific immune system cells called killer T lymphocytes from induced pluripotent stem cells (iPS cells). To create these killer cells, the team first had to reprogram T lymphocytes specialized in killing a certain type of cancer, into iPS cells. The iPS cells then generated fully active, cancer-specific T lymphocytes. These lymphocytes regenerated from iPS cells could potentially serve as cancer therapy in the future.
Science Daily, Dec 27, 2012
Raul Vizcardo, et al, Regeneration of Human Tumor Antigen-Specific T Cells from iPSCs Derived from Mature CD8+ T Cells.
Cell Stem Cell, 2012; 12 (1): 31-36 

Researchers Identify Water Rich Meteorite Linked To Mars Crust

NASA-funded researchers analyzing a small meteorite that may be the first discovered from the Martian surface or crust have found it contains 10 times more water than other Martian meteorites from unknown origins.
This new class of meteorite was found in 2011 in the Sahara Desert. Designated Northwest Africa (NWA) 7034, and nicknamed "Black Beauty," it weighs approximately 11 ounces (320 grams). After more than a year of intensive study, a team of U.S. scientists determined the meteorite formed 2.1 billion years ago during the beginning of the most recent geologic period on Mars, known as the Amazonian.

NASA Mission News - Jan. 3, 2012
Science DOI: 10.1126/science.1228858

Your Brain On Big Bird: Sesame Street Helps to Reveal Patterns of Neural Development

Using brain scans of children and adults watching Sesame Street, cognitive scientists are learning how children's brains change as they develop intellectual abilities like reading and math,
Scientists are just beginning to use brain imaging to understand how humans process thought during real-life experiences. For example, researchers have compared scans of adults watching an entertaining movie to see if neural responses are similar across different individuals. "But this is the first study to use the method as a tool for understanding development," says lead author Jessica Cantlon, an assistant professor in brain and cognitive sciences at the University of Rochester.

Science Daily, Jan 3, 2012

Cantlon JF, Li R.

Neural Activity during Natural Viewing of Sesame Street Statistically Predicts Test Scores in Early Childhood. 

PLoS Biol, 2013; 11(1): e1001462 DOI:10.1371/journal.pbio.1001462

2012: Signaling Breakthroughs of the Year

With input from the members of the Board of Reviewing Editors and editorial staff, Science Signaling puts the spotlight on the hottest signaling research of 2012. The connection between signaling and metabolism continues to be an important area. Signaling breakthroughs in cancer, immunology, developmental biology, neuroscience, and microbiology all made the list. Structural and molecular insights into signaling proteins and networks are also beginning to not only yield potential therapeutic targets but also lead to successful efforts between synthetic biologists and clinicians in the treatment of cancer.

Sci. Signal., 1 January 2013 Vol. 6, Issue 256, p. eg1 [DOI: 10.1126/scisignal.2003881]

The NaV1.7 sodium channel: from molecule to man

The voltage-gated sodium channel NaV1.7 is preferentially expressed in peripheral somatic and visceral sensory neurons, olfactory sensory neurons and sympathetic ganglion neurons. NaV1.7 accumulates at nerve fibre endings and amplifies small subthreshold depolarizations, poising it to act as a threshold channel that regulates excitability. Genetic and functional studies have added to the evidence that NaV1.7 is a major contributor to pain signalling in humans, and homology modelling based on crystal structures of ion channels suggests an atomic-level structural basis for the altered gating of mutant NaV1.7 that causes pain.

Sulayman D. Dib-Hajj, et al.

Nature Reviews Neuroscience 14, 49-62 (January 2013) | doi:10.1038/nrn3404