Recent studies indicate that dopamine neurons in the ventral tegmental area (VTA) and substantia nigra pars compacta (SNc) convey distinct signals. To explore this difference, we comprehensively ...identified each area's monosynaptic inputs using the rabies virus. We show that dopamine neurons in both areas integrate inputs from a more diverse collection of areas than previously thought, including autonomic, motor, and somatosensory areas. SNc and VTA dopamine neurons receive contrasting excitatory inputs: the former from the somatosensory/motor cortex and subthalamic nucleus, which may explain their short-latency responses to salient events; and the latter from the lateral hypothalamus, which may explain their involvement in value coding. We demonstrate that neurons in the striatum that project directly to dopamine neurons form patches in both the dorsal and ventral striatum, whereas those projecting to GABAergic neurons are distributed in the matrix compartment. Neuron-type-specific connectivity lays a foundation for studying how dopamine neurons compute outputs.
► Tracing direct inputs to midbrain dopamine (DA) neurons using rabies virus ► DA neurons receive direct inputs from autonomic, motor and somatosensory areas ► Direct cortical and subthalamic inputs may explain short-latency excitation of SNc ► The largest numbers of direct inputs come from dorsal and ventral striatum patches
Understanding how the activity of a given type of neuron is regulated requires understanding their inputs. Watabe-Uchida et al. applied a rabies-virus-mediated tracing method to midbrain dopamine neurons to provide a comprehensive view of their inputs.
Mariculture is a rapidly developing industrial sector. Generally, fish are maintained in net cages with high density. Cage culture systems allow uncontrolled flow of sea water containing potentially ...infectious stages of fish parasites. In such culture conditions, prevention of such parasitic infections is difficult for parasites with life cycles that complete within culture sites, among which monogeneans and blood flukes are the most important platyhelminthes. Intense monogenean infections induce respiratory and osmo-regulatory dysfunctions. A variety of control measures have been developed, including freshwater bath treatment and chemotherapy. The potential to control monogenean infections through selective breeding, modified culture techniques to avoid infection, and general fish health management are discussed. It should be noted that mariculture conditions have provided some host-specific monogeneans with a chance to expand their host ranges. Blood flukes sometimes induce mass mortality among farmed fish. In-feed administration of praziquantel is the best solution to treat infected fish. Some cases are described that show how international trade in marine fish has resulted in the spread of hitherto unknown parasites into indigenous farmed and wild fish.
Abstract
The recently discovered kagome superconductors
A
V
3
Sb
5
(
A
= K, Rb, Cs) exhibit unusual charge-density-wave (CDW) orders with time-reversal and rotational symmetry breaking. One of the ...most crucial unresolved issues is identifying the symmetry of the superconductivity that develops inside the CDW phase. Theory predicts a variety of unconventional superconducting symmetries with sign-changing and chiral order parameters. Experimentally, however, superconducting phase information in
A
V
3
Sb
5
is still lacking. Here we report the impurity effects in CsV
3
Sb
5
using electron irradiation as a phase-sensitive probe of superconductivity. Our magnetic penetration depth measurements reveal that with increasing impurities, an anisotropic fully-gapped state changes to an isotropic full-gap state without passing through a nodal state. Furthermore, transport measurements under pressure show that the double superconducting dome in the pressure-temperature phase diagram survives against sufficient impurities. These results support that CsV
3
Sb
5
is a non-chiral, anisotropic
s
-wave superconductor with no sign change both at ambient and under pressure.
Skeletal muscle depletion, referred to as sarcopenia, predicts morbidity and mortality in patients undergoing digestive surgery. However, the impact on liver transplantation is unclear. The present ...study investigated the impact of sarcopenia on patients undergoing living donor liver transplantation (LDLT). Sarcopenia was assessed by a body composition analyzer in 124 adult patients undergoing LDLT between February 2008 and April 2012. The correlation of sarcopenia with other patient factors and the impact of sarcopenia on survival after LDLT were analyzed. The median ratio of preoperative skeletal muscle mass was 92% (range, 67–130%) of the standard mass. Preoperative skeletal muscle mass was significantly correlated with the branched‐chain amino acids to tyrosine ratio (r = −0.254, p = 0.005) and body cell mass (r = 0.636, p < 0.001). The overall survival rate in patients with low skeletal muscle mass was significantly lower than in patients with normal/high skeletal muscle mass (p < 0.001). Perioperative nutritional therapy significantly increased overall survival in patients with low skeletal muscle mass (p = 0.009). Multivariate analysis showed that low skeletal muscle mass was an independent risk factor for death after transplantation. In conclusion, sarcopenia was closely involved with posttransplant mortality in patients undergoing LDLT. Perioperative nutritional therapy significantly improved overall survival in patients with sarcopenia.
Sarcopenia is closely involved with posttransplant mortality in patients undergoing living donor liver transplantation and perioperative nutritional therapy significantly improves overall survival, even in patients with sarcopenia.
Serotonin and dopamine are major neuromodulators. Here, we used a modified rabies virus to identify monosynaptic inputs to serotonin neurons in the dorsal and median raphe (DR and MR). We found that ...inputs to DR and MR serotonin neurons are spatially shifted in the forebrain, and MR serotonin neurons receive inputs from more medial structures. Then, we compared these data with inputs to dopamine neurons in the ventral tegmental area (VTA) and substantia nigra pars compacta (SNc). We found that DR serotonin neurons receive inputs from a remarkably similar set of areas as VTA dopamine neurons apart from the striatum, which preferentially targets dopamine neurons. Our results suggest three major input streams: a medial stream regulates MR serotonin neurons, an intermediate stream regulates DR serotonin and VTA dopamine neurons, and a lateral stream regulates SNc dopamine neurons. These results provide fundamental organizational principles of afferent control for serotonin and dopamine.
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•Monosynaptic inputs to serotonin neurons in the DR and MR•Inputs to DR and MR serotonin neurons are spatially shifted in the forebrain•DR serotonin and VTA dopamine neurons receive similar inputs, except from striatum•Three input streams control serotonin and dopamine
Serotonin or dopamine neurons project throughout the brain and control many behaviors. Despite their importance, little is known about how serotonin and dopamine neurons are regulated, partly because of anatomical complexity. Here, Ogawa et al. used a modified rabies virus to systematically map direct inputs to serotonin neurons and found a surprising similarity of inputs between a group of serotonin neurons and a group of dopamine neurons. These results give a global picture of serotonin and dopamine neural circuits.
The formation and retrieval of a memory is thought to be accomplished by activation and reactivation, respectively, of the memory-holding cells (engram cells) by a common set of neural circuits, but ...this hypothesis has not been established. The medial temporal-lobe system is essential for the formation and retrieval of episodic memory for which individual hippocampal subfields and entorhinal cortex layers contribute by carrying out specific functions. One subfield whose function is poorly known is the subiculum. Here, we show that dorsal subiculum and the circuit, CA1 to dorsal subiculum to medial entorhinal cortex layer 5, play a crucial role selectively in the retrieval of episodic memories. Conversely, the direct CA1 to medial entorhinal cortex layer 5 circuit is essential specifically for memory formation. Our data suggest that the subiculum-containing detour loop is dedicated to meet the requirements associated with recall such as rapid memory updating and retrieval-driven instinctive fear responses.
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•dSub and the circuit, CA1→dSub→EC5, are required for hippocampal memory retrieval•The direct CA1→EC5 circuit is essential for hippocampal memory formation•The dSub→MB circuit regulates memory-retrieval-induced stress hormone responses•The dSub→EC5 circuit contributes to context-dependent memory updating
Episodic memories are formed and retrieved through distinct hippocampal pathways.
We have discovered room-temperature low-field colossal magnetoresistance (CMR) in an A-site ordered NdBaMn2O6 crystal. The resistance changes more than 2 orders of magnitude at a magnetic field lower ...than 2 T near 300 K. When the temperature and magnetic field sweep from an insulating (metallic) phase to a metallic (insulating) phase, the insulating (metallic) conduction changes to the metallic (insulating) conduction within 1 K and 0.5 T, respectively. The CMR is ascribed to the melting of the charge and orbital ordering. The entropy change which is estimated from the B−T phase diagram is smaller than what is expected for the charge and orbital ordering. The suppression of the entropy change is attributable to the loss of the short-range ferromagnetic fluctuation of Mn spin moments, which is an important key of the high temperature and low magnetic field CMR effect.
Observers learn to fear the context in which they witnessed a demonstrator's aversive experience, called observational contextual fear conditioning (CFC). The neural mechanisms governing whether ...recall of the observational CFC memory occurs from the observer's own or from the demonstrator's point of view remain unclear. Here, we show in male mice that recent observational CFC memory is recalled in the observer's context only, but remote memory is recalled in both observer and demonstrator contexts. Recall of recent memory in the observer's context requires dorsal hippocampus activity, while recall of remote memory in both contexts requires the medial prefrontal cortex (mPFC)-basolateral amygdala pathway. Although mPFC neurons activated by observational CFC are involved in remote recall in both contexts, distinct mPFC subpopulations regulate remote recall in each context. Our data provide insights into a flexible recall strategy and the functional reorganization of circuits and memory engram cells underlying observational CFC memory.
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•Discontinuous nozzle induces the flow to choke at the discontinuity location.•At the nozzle exit, the particle velocity reaches 190 m.s−1 for 60 μm diameter.•During cold-spray, ...polymeric particles are submitted to important thermal gradient.
The manufacture of polymer coatings via the cold-spray process remains challenging owing to the viscoelastic-viscoplastic behavior exhibited by polymers. One crucial step to improve cold-spray polymer coating is to determine the particles’ thermal history during their flight from inside the nozzle to their impact on the substrate. In this study, we propose estimating the velocity and temperature of an isolated polymer particle traveling through a nozzle with a sharp change in its cross-section. The preliminary results show that the geometric discontinuity constricts the flow, thereby increasing the particle velocity. Moreover, a significant thermal gradient is expected inside the particle, which in turn leads to a gradient of mechanical properties of the polymeric particle during impact.
Dopamine and serotonin play critical roles in flexible behaviors and are related to various psychiatric and motor disorders. This paper reviews the global organization of dopamine and serotonin ...systems through recent findings using a modified rabies virus. We first introduce methods for comprehensive mapping of monosynaptic inputs. We then describe quantitative comparisons across the data regarding monosynaptic inputs to dopamine neurons versus serotonin neurons. There is surprising similarity between the input to dopamine neurons in the ventral tegmental area (VTA) and the input to serotonin neurons in the dorsal raphe (DR), suggesting functional interactions between these systems. We next introduce studies of mapping monosynaptic inputs to subpopulations of dopamine neurons specified by their projection targets. It was found that the population of dopamine neurons that project to the tail of the striatum (TS) forms an anatomically distinct outlier, suggesting a unique function. From these series of anatomical studies, we propose that there are three information flows that regulate these neuromodulatory systems: the midline stream to serotonin neurons in median raphe (MR) and B6, the central stream to value-coding dopamine neurons and serotonin neurons in rostral DR, and the lateral stream to TS-projecting dopamine neurons. Finally we introduce a new approach to investigate firing patterns of monosynaptic inputs to dopamine neurons in behaving animals. Combining anatomical and physiological findings, we propose that within the central stream, dopamine neurons broadcast a central teaching signal rather than personal teaching signals to multiple brain areas, which are computed in a redundant way in multi-layered neural circuits. Examination of global organization of the dopamine and serotonin circuits not only revealed the complexity of the systems but also revealed some principles of their organization. We will also discuss limitations, practical issues and the possibility of future improvements of the rabies virus-mediated tracing system.
•Global organization of the dopamine and serotonin systems•Three input streams that regulate dopamine and serotonin neurons•Anatomical & electrophysiological mapping of monosynaptic inputs using rabies virus•Discuss recent advances and limitations of modified rabies virus system
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