Neuronal processing is classically conceptualized as dendritic input, somatic integration, and axonal output. The axon initial segment, the proposed site of action potential generation, usually ...emanates directly from the soma. However, we found that axons of hippocampal pyramidal cells frequently derive from a basal dendrite rather than from the soma. This morphology is particularly enriched in central CA1, the principal hippocampal output area. Multiphoton glutamate uncaging revealed that input onto the axon-carrying dendrites (AcDs) was more efficient in eliciting action potential output than input onto regular basal dendrites. First, synaptic input onto AcDs generates action potentials with lower activation thresholds compared with regular dendrites. Second, AcDs are intrinsically more excitable, generating dendritic spikes with higher probability and greater strength. Thus, axon-carrying dendrites constitute a privileged channel for excitatory synaptic input in a subset of cortical pyramidal cells.
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•Axons derive from a dendrite in a large proportion of hippocampal pyramidal neurons•Axon-carrying dendrites have higher propensity to generate dendritic spikes•Input to axon-carrying dendrites elicits action potentials with lower threshold•Structure of hippocampal principal neurons mediates asymmetric input processing
Thome et al. find that axons of hippocampal pyramidal cells frequently derive from a basal dendrite rather than from the soma. These dendrites constitute a privileged channel for excitatory synaptic input, generating a major functional asymmetry in a subset of cortical neurons.
Abstract
The article is concerned with peculiarities study of the quasimonochromatic optical fluxes propagation through thin planar transparent layer of multilayer coating. There is shown that these ...fluxes can be transported by the layer in process of its multiple consequtive total internal reflection or by the waveguide-resonance propagation manner depending on correlation between the layer width and the radiation coherence length half of transported fluxes. Efficiency comparison of these radiation transportation mechanisms showed that the waveguide-resonance propagation approach is more adequate for results description of the optical waveguides functioning. It allowed to conclude that optical waveguides (fibers) function in frame of the waveguide-resonance paradigm and the waveguide-resonance mechanism is responsible for the light fluxes transportation on great distances.
DANSS is a highly segmented 1 m3 plastic scintillator detector. Its 2500 one meter long scintillator strips have a Gd-loaded reflective cover. The DANSS detector is placed under an industrial 3.1 ...GWth reactor of the Kalinin Nuclear Power Plant 350 km NW from Moscow. The distance to the core is varied on-line from 10.7 m to 12.7 m. The reactor building provides about 50 m water-equivalent shielding against the cosmic background. DANSS detects almost 5000 ν˜e per day at the closest position with the cosmic background less than 3%. The inverse beta decay process is used to detect ν˜e. Sterile neutrinos are searched for assuming the 4ν model (3 active and 1 sterile ν). The exclusion area in the Δm142,sin22θ14 plane is obtained using a ratio of positron energy spectra collected at different distances. Therefore results do not depend on the shape and normalization of the reactor ν˜e spectrum, as well as on the detector efficiency. Results are based on 966 thousand antineutrino events collected at three different distances from the reactor core. The excluded area covers a wide range of the sterile neutrino parameters up to sin22θ14<0.01 in the most sensitive region.
ABSTRACT
The ionization state and oxygen abundance distribution in a sample of polar-ring galaxies (PRGs) were studied from the long-slit spectroscopic observations carried out with the SCORPIO-2 ...focal reducer at the Russian 6-m telescope. The sample consists of 15 PRGs classified as ‘the best candidates’ in the SDSS-based Polar Ring Catalogue. The distributions of line-of-sight velocities of stellar and gaseous components have given kinematic confirmation of polar structures in 13 galaxies in the sample. We show that ionization by young stars dominates in the external parts of polar discs, while shocks have a significant contribution to gas excitation in the inner parts of polar structures. This picture was predicted earlier in a toy model implying the collision between gaseous clouds on polar orbits with the stellar disc gravitational potential well. The exception is a moderately inclined ring to the host galaxy NGC 5014: the accreted gas in the centre has already settled on the main plane and ionized by young stars, while the gas in the internal part of the ring is excited by shocks. The present study three times increases the number of polar structures with available oxygen abundance estimation. The measured values of the gas metallicity almost do not depend on the galaxy luminosity. The radial O/H gradient in the considered polar rings is shallow or absent. No metal-poor gas was detected. We ruled out the scenario of the formation of polar rings due to cold accretion from cosmic filaments for the considered sample of PRGs.
Search for bound states in
,
, and
systems is performed by employing coupled homogeneous integral Faddeev equations written in terms of
-matrix components. Instead of the traditional partial-wave ...expansion, a direct integration with respect to angular variables is used in these equations, and three-body coupling in the phase space of each of the
–
–
,
–
–
, and
–
–
systems is taken precisely into account within this approach. Two-body
matrices are the only ingredient of the proposed method. In the case of two-body
interaction, they are found by solving the coupled Lippmann–Schwinger integral equations for the
–
–
system in the (
,
) state, the
system in the (
,
) state, the
–
system in the (
,
) state, and the
–
–
system in the (
,
) state. An updated version of the ESC16 microscopic model is used to obtain two-body
,
YY
, and
YN
interactions generating
matrices. Two-body
NN
interaction is reconstructed on the basis of the charge-dependent Bonn model. Direct numerical calculations of the binding energy for the systems being considered clearly indicate that either of the
and
systems has one bound state with binding energies of 4.5 and 5.5 MeV, respectively, and that the
system has two bound states with binding energies of 2.7 and 4.4 MeV.
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The work presents short descriptions of ion beam methods and X-ray diagnostics in conditions of the total external reflection geometry with accent on the planar nanostructures peculiarities study. ...These objects specificity is described, and these are formulated tasks, which are more suitable for these method applications. Experimental results, which confirm the high efficiency of real objects investigation by these methods are discussed. Possible directions of ion beam analysis and X-ray methodical background on base of the planar X-ray waveguide-resonators application are pointed. The profit from its devises use is re-ndered.
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The work presents short characteristics of the X-ray fluxes waveguide-resonance propagation phenomenon. There is described peculiarities of the X-ray nanophotonics base device functioned in frame ...of the phenomenon – the planar X-ray waveguide-resonator and denoted directions of its development. X-ray waveguide-resonance devices elaboration in the process of base construction modification are discussed.
The processes of neutrino oscillations in an external constant almost homogeneous magnetic field are described in the framework of a new quantum field-theoretical approach. It is based on the Feynman ...diagram technique with a modified distance-dependent propagator, which takes into account the geometry of neutrino oscillation experiments. In the geometry of the solar neutrino experiments, with the extended solar core being the source, the finite size of the source is taken into account and specific examples are considered, where neutrinos are detected through only the charged-current interactions or through both the charged- and neutral-current interactions.
The interplay between hippocampus and medial entorhinal cortex (mEC) is of key importance for forming spatial representations. Within the hippocampal-entorhinal loop, the hippocampus receives ...context-specific signals from layers II/III of the mEC and feeds memory-associated activity back into layer V (LV). The processing of this output signal within the mEC, however, is largely unknown. We characterized the activation of the receiving mEC network by evoked and naturally occurring output patterns in mouse hippocampal-entorhinal cortex slices. Both types of glutamatergic neurons (mEC LVa and LVb) as well as fast-spiking inhibitory interneurons receive direct excitatory input from the intermediate/ventral hippocampus. Connections between the two types of excitatory neurons are sparse, and local processing of hippocampal output signals within mEC LV is asymmetric, favoring excitation of far projecting LVa neurons over locally projecting LVb neurons. These findings suggest a new role for mEC LV as a bifurcation gate for feedforward (telencephalic) and feedback (entorhinal-hippocampal) signal propagation.
Patterned network activity in hippocampal networks plays a key role in the formation and consolidation of spatial memories. It is, however, largely unclear how information is transferred to the neocortex for long-term engrams. Here, we elucidate the propagation of network activity from the hippocampus to the medial entorhinal cortex. We show that patterned output from the hippocampus reaches both major cell types of deep entorhinal layers. These cells are, however, only weakly connected, giving rise to two parallel streams of activity for local and remote signal propagation, respectively. The relative weight of both pathways is regulated by local inhibitory interneurons. Our data reveal important insights into the hippocampal-neocortical dialogue, which is of key importance for memory consolidation in the mammalian brain.
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