Platelet precursors display bipolar behavior

In this issue, Thon et al. (2010. J. Cell Biol. doi: 10.1083/jcb.201006102) demonstrate that newly released platelets exhibit bipolar behavior, shifting back and forth between round cells and multibodied proplatelets (Thon et al., 2010). The authors define this intermediate as a preplatelet and, in doing so, shed new insight into the terminal steps of platelet maturation.     

A nose by any other name (should smell as sweetly)

The standard view that the control of mating behavior by pheromones is mediated by the vomeronasal organ, and not by the main olfactory epithelium, has recently been called into question. In this issue of Cell, two independent studies (Boehm et al., 2005; Yoon et al., 2005) examine the inputs from each of these olfactory pathways to a population of neurons that plays a central role in mating behavior.     

The dynamics of learning and behavioral flexibility

Fundamental to behavior is the capacity to distinguish beneficial from detrimental environmental stimuli. In this issue of Neuron, a new study by Morrison et?al. shows that underlying these processes are qualitatively different dynamical interactions between brain structures involved in processing the value of environmental stimuli.     

Movement, confusion, and orienting in frontal cortices

In this issue, two studies, by Ehrlich et?al. and Hill et?al., address the role of the frontal motor cortices in behavior of the rat and suggest a potential role for this structure in high-level control of diverse behaviors. Hill et?al. show that motor cortical neurons predict whisker movements even without sensory feedback and that their activity reflects efferent control. Surprisingly, Ehrlich et?al. report the participation of this same cortical region in the preparation and execution of orienting behaviors.     

Attending to features inside and outside the spotlight of attention

Previous studies in monkeys and humans have revealed neural correlates and perceptual consequences of feature-based attention. In this issue of Neuron, two brain-imaging studies from Serences and Boynton and Liu et al. bridge the gap between single neurons and behavior by demonstrating a highly functional attention system that acts on neural representations of our visual world enhancing the processing of the currently attended set of features at the expense of information about less relevant aspects.     

Dissecting the quorum-sensing receptor LuxN

Quorum sensing plays a key role in the behavior of many bacteria and is carried out by a wide diversity of secreted molecules and their receptors. In this issue, Swem et al. (2008) provide a detailed site-specific analysis of the functioning of the quorum-sensing receptor LuxN from Vibrio harveyi.     

Fool me once, shame on you; fool me twice, shame on oxytocin

In this issue of Neuron, a study by Baumgartner et al. investigates the influence of oxytocin on trust behavior and its neural mechanisms. The authors report that, following breaches of trust, oxytocin facilitates prosocial behavior while modulating neural signals in the amygdala and caudate nucleus. The findings have implications for an array of mental disorders where social behavior is compromised.     

How to remake a fibroblast into a neural stem cell

In this issue of Cell Stem Cell and in a recent issue of PNAS, Thier et?al. (2012), Han et?al. (2012), and Lujan et?al. (2012) report the derivation of multipotent neural stem/progenitor cells from cultured mouse fibroblasts using distinct reprograming approaches.     

The multiple faces of RIM

Rab3 interacting molecules (RIMs) are highly enriched in the active zones of presynaptic terminals. It is generally thought that they operate as effectors of the small G protein Rab3. Three recent papers, by Han et al. (this issue of Neuron), Deng et al. (this issue of Neuron), and Kaeser et al. (a recent issue of Cell), shed new light on the functional role of RIM in presynaptic terminals. First, RIM tethers Ca2+ channels to active zones. Second, RIM contributes to priming of synaptic vesicles by interacting with another presynaptic protein, Munc13.     

Molecular Reproduction & Development Volume 79, Issue 4, April 2012 cover image

In sea urchins, a soluble coat of egg jelly induces morphological and physiological changes in spermatozoa. This colorized scanning electron micrograph is a snapshot of such activated sperm. In this issue, Kazama et al. identify the reactive oxygen species that are generated by this process and that may influence sperm behavior.     

Two oscillators are better than one: a circadian pacemaker escapes from the light

Continuous light exposure can suppress circadian rhythms. In this issue of Neuron, Murad et al. demonstrate that, under certain genetic conditions, a novel cluster of pacemaker neurons can drive rhythmic behavior in constant light. Surprisingly, these neurons are distinct from those thought to drive rhythms in constant darkness.     

Behavioral flexibility and the frontal lobe

Brain areas in the frontal lobe have been implicated in behavioral flexibility and control. The study by Johnston et al. in this issue of Neuron provides novel insights into the roles of the prefrontal and anterior cingulate cortices in controlling behavior.     

Ultrasensitivity and positive feedback to promote sharp mitotic entry

In this issue, Trunnell et?al. (2011) show that in mitotic entry the positive feedback that drives the activation of cyclin-dependent kinase (Cdk) involves a very ultrasensitive step of phosphorylation of Cdc25C by Cdk, thus strongly contributing to the switch-like behavior of this essential cell-cycle transition.     

CUE'd up for Monoubiquitin

The first structures have been obtained for complexes between CUE domains and monoubiquitin, one by NMR (Kang et al., this issue of Cell) and one by X-ray crystallography (Prag et al., this issue of Cell), thus providing insights into ubiquitin recognition by CUE domains. Structural comparisons suggest that different CUE surfaces can interact with ubiquitin, indicating that not all CUE domains are created equal.     

PKG and the neural basis for behavioral phenotypes

Cyclic GMP-dependent protein kinase (PKG) has been implicated in the regulation of diverse aspects of vertebrate and insect behavior, yet the mechanisms underlying these effects are poorly understood. In this issue of Neuron, Fujiwara et al. and L'Etoile et al. address the neural basis for PKG function in C. elegans and demonstrate the power of behavioral genetic analysis in simple systems in the elucidation of neuronal signaling mechanisms in vivo.     

Can 1000 reviews be wrong? Actin, alpha-Catenin, and adherens junctions

Coupling between cell adhesion and the actin cytoskeleton is thought to require a stable link between the cadherin-catenin complex and actin that is mediated by alpha-catenin. In this issue of Cell, the Weis and Nelson groups call this static model into question, showing that alpha-catenin can directly regulate actin dynamics (Drees et al., 2005 and Yamada et al., 2005).     

TIP maker and TIP marker; EB1 as a master controller of microtubule plus ends

The EB1 protein is a member of the exciting and enigmatic family of microtubule (MT) tip-tracking proteins. EB1 acts as an exquisite marker of dynamic MT plus ends in some cases, whereas in others EB1 is thought to directly dictate the behavior of the plus ends. How EB1 differentiates between these two roles remains unclear; however, a growing list of interactions between EB1 and other MT binding proteins suggests there may be a single mechanism. Adding another layer of complexity to these interactions, two studies published in this issue implicate EB1 in cross-talk between mitotic MTs and between MTs and actin filaments (Goshima et al., p. 229; Wu et al., p. 201). These results raise the possibility that EB1 is a central player in MT-based transport, and that the activity of MT-binding proteins depends on their ability or inability to interact with EB1.     

Is the movement representation in the motor cortex a moving target?

In redundant neural networks, many different combinations of connection weights will produce the same output, thereby providing many possible solutions for a given computation. In this issue of Neuron, Rokni et al. propose that the arm movement representations in the cerebral cortex act like redundant networks that drift randomly between different synaptic configurations with equivalent input-output behavior because of random noise in the adaptive learning mechanism.     

Unraveling autism

In this issue of AJHG, Alarcón et al.,(1) Arking et al.,(2) and Bakkaloglu et al.(3) identify a series of functional variants in the CNTNAP2 gene that unequivocally implicate this gene as causing Type 1 autism in the general population.