Woman With Quadriplegia Feeds Herself Chocolate Using Mind-Controlled Robot Arm

Reaching out to high five someone, grasping and moving objects of different shapes and sizes, feeding herself dark chocolate. For Jan Scheuermann and a team of researchers from the University of Pittsburgh School of Medicine and UPMC, accomplishing these seemingly ordinary tasks demonstrated for the first time that a person with longstanding quadriplegia can maneuver a mind-controlled, human-like robot arm in seven dimensions (7D) to consistently perform many of the natural and complex motions of everyday life.
UPMC/University of Pittsburgh Schools of the Health Sciences, News release on Dec 16, 2012

CBS 60 Minutes, Dec 30, 2012

12 Matter Particles Suffice in Nature: Limited Number of Fermions in Standard Model?

How many matter particles exist in nature? Particle physicists have been dealing with this question for a long time. The 12 matter particles contained in the standard model of particle physics? Or are there further particles with too high a mass to be produced by the experiments performed so far? These questions are now answered by researchers of KIT, CERN, and Humboldt University in the current issue of the Physical Review Letters

Science Daily - Dec. 13, 2012

Physical Review Letters, 2012; 109 (24) DOI :10.1103/PhysRevLett.109.241802

Ediacaran life on land

Fossils found in rocks of the Ediacaran period in Australia have been previously characterized as early marine organisms. But a report suggests that these rocks are fossilized soils. So did some of these Ediacaran organisms in fact live on land, like lichens? A palaeontologist and a geologist weigh up the evidence.

Shuhai Xiao & L. Paul Knauth
Nature 493, 28–29 (03 January 2013) doi:10.1038/nature11765nline 12 December 2012

'Obamadon' was wiped out by the asteroid

Asteroid that killed the dinosaurs also wiped out the ‘Obamadon’,
The asteroid collision widely thought to have killed the dinosaurs also led to extreme devastation among snake and lizard species, according to new research — including the extinction of a newly identified lizard Yale and Harvard scientists have named Obamadon gracilis. The published paper can be fund here.

Evolution of GluN2A/B cytoplasmic domains diversified vertebrate synaptic plasticity and behavior

Understanding the mechanisms underlying the many forms of vertebrate behavior is a central objective of neuroscience and, although studied extensively at the cellular and circuit levels, very little is known about the underlying molecular evolutionary events. How did genome evolution give rise to the many forms of learning, emotional behavior and motor functions and generate the subtlety of synaptic regulation that is manifest in the mammalian brain?

Two genome duplications early in the vertebrate lineage expanded gene families, including GluN2 subunits of the NMDA receptor. Diversification between the four mammalian GluN2 proteins occurred primarily at their intracellular C-terminal domains (CTDs). To identify shared ancestral functions and diversified subunit-specific functions, the authors exchanged the exons encoding the GluN2A (also known as Grin2a) and GluN2B (also known as Grin2b) CTDs in two knock-in mice and analyzed the mice's biochemistry, synaptic physiology, and multiple learned and innate behaviors. The eight behaviors were genetically separated into four groups, including one group comprising three types of learning linked to conserved GluN2A/B regions. In contrast, the remaining five behaviors exhibited subunit-specific regulation. GluN2A/B CTD diversification conferred differential binding to cytoplasmic MAGUK proteins and differential forms of long-term potentiation. These data indicate that vertebrate behavior and synaptic signaling acquired increased complexity from the duplication and diversification of ancestral GluN2 genes.

Tomás J Ryan,  et al.
Nature Neuroscience 16, 25–32 (2013) doi:10.1038/nn.3277

Neurogliaform cells dynamically regulate somatosensory integration via synapse-specific modulation

Despite the prevailing idea that neurogliaform cells produce a spatially unrestricted widespread inhibition, the authors demonstrate here that their activity attenuates thalamic-evoked feed-forward inhibition in layer IV barrel cortex but has no effect on feed-forward excitation. The result of this circuit selectivity is a dynamic regulation in the temporal window for integration of excitatory thalamic input, thus revealing a new role for neurogliaform cells in shaping sensory processing.

Ramesh Chittajallu, Kenneth A Pelkey & Chris J McBain

Nature Neuroscience 16, 13–15 (2013) doi:10.1038/nn.3284

Arisaka's Physics Colloquium on Dark Matter

Katsushi Arisaka gave a Physics Colloquium at UCLA to review the status of dark matter researches. Presentation is available either as PDF or PPT files.

Genomic variation landscape of the human gut microbiome

Whereas large-scale efforts have rapidly advanced the understanding and practical impact of human genomic variation, the practical impact of variation is largely unexplored in the human microbiome. The authors developed a framework for metagenomic variation analysis and applied it to 252 faecal metagenomes of 207 individuals from Europe and North America. Using 7.4 billion reads aligned to 101 reference species, they detected 10.3 million single nucleotide polymorphisms (SNPs), 107,991 short insertions/deletions, and 1,051 structural variants. The average ratio of non-synonymous to synonymous polymorphism rates of 0.11 was more variable between gut microbial species than across human hosts. Subjects sampled at varying time intervals exhibited individuality and temporal stability of SNP variation patterns, despite considerable composition changes of their gut microbiota. This indicates that individual-specific strains are not easily replaced and that an individual might have a unique metagenomic genotype, which may be exploitable for personalized diet or drug intake.

Siegfried Schloissnig et al.
Nature 493, 45–50 (03 January 2013) doi:10.1038/nature11711
Published online 05 December 2012

Synaptic scaffold evolution generated components of vertebrate cognitive complexity

The origins and evolution of higher cognitive functions, including complex forms of learning, attention and executive functions, are unknown. A potential mechanism driving the evolution of vertebrate cognition early in the vertebrate lineage (550 million years ago) was genome duplication and subsequent diversification of postsynaptic genes. Here the authors report the first genetic analysis of a vertebrate gene family in cognitive functions measured using computerized touchscreens. Comparison of mice carrying mutations in each of the four Dlg paralogs showed that simple associative learning required Dlg4, whereas Dlg2 and Dlg3 diversified to have opposing functions in complex cognitive processes. Exploiting the translational utility of touchscreens in humans and mice, testing Dlg2 mutations in both species showed that Dlg2's role in complex learning, cognitive flexibility and attention has been highly conserved over 100 million years. Dlg-family mutations underlie psychiatric disorders, suggesting that genome evolution expanded the complexity of vertebrate cognition at the cost of susceptibility to mental illness.
Jess Nithianantharajah, et al.
Nature Neuroscience 16, 16–24 (2013) doi:10.1038/nn.3276

Encoding asymmetry within neural circuits

Genetic and environmental factors control morphological and functional differences between the two sides of the nervous system. Neural asymmetries are proposed to have important roles in circuit physiology, cognition and species-specific behaviours. We propose two fundamentally different mechanisms for encoding left–right asymmetry in neural circuits. In the first, asymmetric circuits share common components; in the second, there are unique unilateral structures. Research in both vertebrates and invertebrates is helping to reveal the mechanisms underlying the development of neural lateralization, but less is known about the function of circuit asymmetries. Technical advances in the coming years are likely to revolutionize our understanding of left–right asymmetry in the nervous system.

Miguel L. Concha, et al.
Nature Reviews Neuroscience 13, 832-843 (December 2012) | doi:10.1038/nrn3371