Subthreshold Resonance Research Articles

Studying subthreshold resonance using the Trojan horse method

The Trojan horse method was employed to indirectly measure the bare-nucleus reaction cross-section and astrophysical S-factor of the 9Be(p,α)6Li reaction in the low-energy region, utilizing the three-body reaction 2H(9Be,α6Li)n. Comparing the two-body reaction data extracted from the Trojan horse method with that obtained through direct measurements, compatibility is observed in the energy region above approximately 100 keV. Additionally, the THM data successfully reproduces the expected low-energy resonance peak around 270 keV. The THM extraction of the astrophysical factor yields S(0) = 21.0 ± 0.8 MeV b, which surpasses the extrapolation obtained from direct measurements. The 9Be(p,α)6Li reaction channel exhibits a subthreshold resonance with a width of 25 keV, positioned approximately -23 keV below the threshold. However, the strong electron shielding effect near the zero energy position in direct measurements often masks the influence of the subthreshold resonance on the low-energy region. In contrast, the THM method allows us to neglect the electron shielding effect. The THM experimental data were subjected to fitting using the Breit-Wigner function and subsequently compared with directly measured data. Following a comprehensive comparative analysis, it was discerned that the S(0) value obtained through THM exceeded the extrapolated value derived from direct measurements. This disparity was primarily attributed to the influence of the subthreshold resonance.

Erratum: Hu et al., "Hyperpolarization-Activated Currents and Subthreshold Resonance in Granule Cells of the Olfactory Bulb".

Erratum: Hu et al., "Hyperpolarization-Activated Currents and Subthreshold Resonance in Granule Cells of the Olfactory Bulb".

Dynamics of interaction between IH and IKLT currents to mediate double resonances of medial superior olive neurons related to sound localization.

Neurons in the medial superior olive (MSO) exhibit high frequency responses such as subthreshold resonance, which is helpful to sensitively detect a small difference in the arrival time of sounds between two ears for precise sound localization. Recently, except for the high frequency depolarization resonance mediated by a low threshold potassium (IKLT) current, a low frequency hyperpolarization resonance mediated by a hyperpolarization-activated cation (IH) current is observed in experiments on the MSO neurons, forming double resonances. The complex dynamics underlying double resonances are studied in an MSO neuron model in the present paper. Firstly, double resonances similar to the experimental observations are simulated as the resting membrane potential is between half-activation voltages of IH and IKLT currents, and stimulation current (IZAP) with large amplitude and exponentially increasing frequency is applied. Secondly, multiple effective factors to modulate double resonances are obtained. Especially, the decrease of time constant of IKLT current and increase of conductance of IH and IKLT currents can enhance the depolarization resonance frequency for precise sound localization. Last, different frequency responses of slow IH and fast IKLT currents in formation of the resonances are acquired. A middle phase difference between IZAP and IKLT currents appears at a high frequency, and the interaction between the positive part of IZAP and the negative IKLT current forms the depolarization resonance. Interaction between the negative part of IZAP and positive IH current with a middle phase difference results in hyperpolarization resonance at a low frequency. Furthermore, the phase difference between IZAP and resonance current can well explain the increase of depolarization resonance frequency modulated by the increase of conductance of IH or IKLT currents. The results present the dynamical and biophysical mechanisms for the double resonances mediated by two currents in the MSO neurons, which is helpful to enhance the depolarization resonance frequency for precise sound localization.

α2-Adrenergic modulation of Ih in adult-born granule cells in the olfactory bulb.

In the olfactory bulb (OB), a large population of axon-less inhibitory interneurons, the granule cells (GCs), coordinate network activity and tune the output of principal neurons, the mitral and tufted cells (MCs), through dendrodendritic interactions. Furthermore, GCs undergo neurogenesis throughout life, providing a source of plasticity to the neural network of the OB. The function and integration of GCs in the OB are regulated by several afferent neuromodulatory signals, including noradrenaline (NA), a state-dependent neuromodulator that plays a crucial role in the regulation of cortical function and task-specific decision processes. However, the mechanisms by which NA regulates GC function are not fully understood. Here, we show that NA modulates hyperpolarization-activated currents (Ih) via the activation of α2-adrenergic receptors (ARs) in adult-born GCs (abGCs), thus directly acting on channels that play essential roles in regulating neuronal excitability and network oscillations in the brain. This modulation affects the dendrodendritic output of GCs leading to an enhancement of lateral inhibition onto the MCs. Furthermore, we show that NA modulates subthreshold resonance in GCs, which could affect the temporal integration of abGCs. Together, these results provide a novel mechanism by which a state-dependent neuromodulator acting on Ih can regulate GC function in the OB.

Spin assignment and statistical properties of neutron resonances from Dy161,163(n,γ) and Er167(n,γ) measured at the DANCE facility

Background: Average resonance spacing ${D}_{0}$ and spin dependence of nuclear level density (NLD) are essential quantities in nuclear physics, especially important for calculations of nuclear reactions and the normalization of NLD models.Purpose: Neutron resonances with different spins in odd-mass targets can form close doublets that are often difficult to resolve. These doublets are not corrected for when accounting for subthreshold resonances during ${D}_{0}$ determination. Moreover, different literature sources disagree on the isotopic assignment of some resonances.Methods: The $\ensuremath{\gamma}$ rays following radiative neutron capture on $^{161,163}\mathrm{Dy}$ and $^{167}\mathrm{Er}$ were measured with the highly segmented $\ensuremath{\gamma}$-ray calorimeter Detector for Advanced Neutron Capture Experiments (DANCE) at the Los Alamos Neutron Science Center. The analysis of spectra using the $\ensuremath{\gamma}$-multiplicity-based spin assignment method allows checking for the presence of the above-mentioned doublets. The calorimetric sensitivity provides unambiguous isotopic assignment.Results: We were able to assign spin to tens of resonances as well as to identify new ones in all three isotopes. Some isotope assignments from the literature were corrected. Detailed analysis of the number of unobserved resonances, assuming that the resonance positions obey predictions of the Gaussian orthogonal ensemble and reduced neutron widths Porter-Thomas fluctuations, allowed determination of ${D}_{0}$ with an uncertainty of a few percent, ${D}_{0}=2.15(5)$, 6.39(24), and 3.86(12) eV for $^{161,163}\mathrm{Dy}$ and $^{167}\mathrm{Er}$, respectively. Thanks to the spin assignment, the spacings for the resonances with the two spins formed in $s$-wave neutron capture, ${D}_{0}^{\ensuremath{-}}$ and ${D}_{0}^{+}$, were determined. Their ratio was compared to different NLD models.Conclusions: Our deduced ${D}_{0}$ for $^{163}\mathrm{Dy}$ is lower than any $^{163}\mathrm{Dy}$ value found in the literature. Good consistency was found with some literature values for $^{161}\mathrm{Dy}$ and $^{167}\mathrm{Er}$. The ratios ${D}_{0}^{\ensuremath{-}}/{D}_{0}^{+}$ are consistent with several models available in the literature, but in a clear contradiction with a few microscopic NLD models.

Noise-induced synchronization stochastic resonance in Hodgkin–Huxley neurons

In this paper, based on the Hodgkin–Huxley (H-H) neuron model, three distinct types of noises are introduced into the input of the neuron. The noises are Gaussian white noise (GWN), Lévy noise and Colored noise, separately. The phenomenon of stochastic resonance under and above threshold in one-dimensional H-H neuron is discussed. First, the responses of H-H neuron to different input signal frequency, amplitude and constant offset stimulation are researched. The neuron membrane potential diagram and spectrum diagram are given. Then, the mutual information rate (MIR) is taken as the evaluation index. The results show that adding a noise of certain intensity can increase the response of neuron to the orignal signal and the MIR between the output and input of neuron has unimodal property, which proves the existence of stochastic resonance under and above the threshold. We also find that neurons have frequency selectivity and different transmission performance for different amplitude of input signals. In addition, the constant offset stimulus should not be too large. Finally, it is discovered that the adaptability of subthreshold stochastic resonance and suprathreshold stochastic resonance (SSR) characteristics characteristics of one-dimensional H-H neurons induced by three distinct types of noises is different. What is more important is that the results of this paper will be instrumental in the future researching on the affect of these three noises in the stochastic resonance of neuron networks.

The voltage and spiking responses of subthreshold resonant neurons to structured and fluctuating inputs: persistence and loss of resonance and variability.

We systematically investigate the response of neurons to oscillatory currents and synaptic-like inputs and we extend our investigation to non-structured synaptic-like spiking inputs with more realistic distributions of presynaptic spike times. We use two types of chirp-like inputs consisting of (i) a sequence of cycles with discretely increasing frequencies over time, and (ii) a sequence having the same cycles arranged in an arbitrary order. We develop and use a number of frequency-dependent voltage response metrics to capture the different aspects of the voltage response, including the standard impedance (Z) and the peak-to-trough amplitude envelope ([Formula: see text]) profiles. We show that Z-resonant cells (cells that exhibit subthreshold resonance in response to sinusoidal inputs) also show [Formula: see text]-resonance in response to sinusoidal inputs, but generally do not (or do it very mildly) in response to square-wave and synaptic-like inputs. In the latter cases the resonant response using Z is not predictive of the preferred frequencies at which the neurons spike when the input amplitude is increased above subthreshold levels. We also show that responses to conductance-based synaptic-like inputs are attenuated as compared to the response to current-based synaptic-like inputs, thus providing an explanation to previous experimental results. These response patterns were strongly dependent on the intrinsic properties of the participating neurons, in particular whether the unperturbed Z-resonant cells had a stable node or a focus. In addition, we show that variability emerges in response to chirp-like inputs with arbitrarily ordered patterns where all signals (trials) in a given protocol have the same frequency content and the only source of uncertainty is the subset of all possible permutations of cycles chosen for a given protocol. This variability is the result of the multiple different ways in which the autonomous transient dynamics is activated across cycles in each signal (different cycle orderings) and across trials. We extend our results to include high-rate Poisson distributed current- and conductance-based synaptic inputs and compare them with similar results using additive Gaussian white noise. We show that the responses to both Poisson-distributed synaptic inputs are attenuated with respect to the responses to Gaussian white noise. For cells that exhibit oscillatory responses to Gaussian white noise (band-pass filters), the response to conductance-based synaptic inputs are low-pass filters, while the response to current-based synaptic inputs may remain band-pass filters, consistent with experimental findings. Our results shed light on the mechanisms of communication of oscillatory activity among neurons in a network via subthreshold oscillations and resonance and the generation of network resonance.

An N/D study of the S 11 channel πN scattering amplitude * *Support in part by National Nature Science Foundations of China (11975028, 10925522), the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) (196253076 -TRR 110)

Extensive dynamical calculations are conducted in the study of channel low energy scatterings, based on various phenomenological model inputs of left cuts at the tree level. The subtleties of the singular behavior of the partial wave amplitude, at the origin of the complex plane, are analysed in detail. Furthermore, it is found that the dispersion representation for the phase shift, , must be modified in the case of scatterings. An additional contribution from the dispersion integral exists, which approximately cancels the contribution of the two virtual poles located near the end points of the segment cut, induced by channel nucleon exchanges. With limited reliance on the details of the dynamical inputs, the subthreshold resonance survives.

New Thermonuclear Rate of 7Li(d,n)24He Relevant to the Cosmological Lithium Problem

Abstract Accurate 7Li(d,n)24He thermonuclear reaction rates are crucial for precise prediction of the primordial abundances of lithium and beryllium and to probe the mysteries beyond fundamental physics and the standard cosmological model. However, uncertainties still exist in current reaction rates of 7Li(d,n)24He widely used in big bang nucleosynthesis (BBN) simulations. In this work, we reevaluate the 7Li(d,n)24He reaction rate using the latest data on the three near-threshold 9Be excited states from experimental measurements. We present for the first time uncertainties that are directly constrained by experiments. Additionally, we take into account for the first time the contribution from the subthreshold resonance at 16.671 MeV of 9Be. We obtain a 7Li(d,n)24He rate that is overall smaller than the previous estimation by about a factor of 60 at the typical temperature of the onset of primordial nucleosynthesis. We implemented our new rate in BBN calculations, and we show that the new rates have a very limited impact on the final light element abundances in uniform density models. Typical abundance variations are in the order of 0.002%. For nonuniform density BBN models, the predicted 7Li production can be increased by 10% and the primordial production of light nuclides with mass number A > 7 can be increased by about 40%. Our results confirm that the cosmological lithium problem remains a long-standing unresolved puzzle from the standpoint of nuclear physics.

Diversity amongst human cortical pyramidal neurons revealed via their sag currents and frequency preferences

In the human neocortex coherent interlaminar theta oscillations are driven by deep cortical layers, suggesting neurons in these layers exhibit distinct electrophysiological properties. To characterize this potential distinctiveness, we use in vitro whole-cell recordings from cortical layers 2 and 3 (L2&3), layer 3c (L3c) and layer 5 (L5) of the human cortex. Across all layers we observe notable heterogeneity, indicating human cortical pyramidal neurons are an electrophysiologically diverse population. L5 pyramidal cells are the most excitable of these neurons and exhibit the most prominent sag current (abolished by blockade of the hyperpolarization activated cation current, Ih). While subthreshold resonance is more common in L3c and L5, we rarely observe this resonance at frequencies greater than 2 Hz. However, the frequency dependent gain of L5 neurons reveals they are most adept at tracking both delta and theta frequency inputs, a unique feature that may indirectly be important for the generation of cortical theta oscillations.

Dynamics of subthreshold and suprathreshold resonance modulated by hyperpolarization-activated cation current in a bursting neuron

Resonance of both subthreshold and suprathreshold membrane potentials has been found in brain or motor neurons involving in the information processing or locomotion control via frequency response, which is mainly related to the hyperpolarization-activated cation current ( $$I_{{\text {h}}}$$ ). In the present paper, the modulations of $$I_{{\text {h}}}$$ current on resonance are acquired in a bursting neuron model, which closely match experimental observations. Firstly, the increase of $$I_{{\text {h}}}$$ current induces stable node changed to stable focus related to Hopf bifurcation, and to bursting via complex bifurcations including the big homoclinic orbit related to type I excitability. Secondly, the subthreshold resonance can be evoked by small stimulation from focus instead of node, resembling the experimental observation that subthreshold resonance appears at strong ( $$I_{{\text {h}}}$$ ) current. Thirdly, the modulation regularity of $$I_{{\text {h}}}$$ current on frequency and amplitude of resonance is simulated, closely matching the experimental observations, which can be well explained with the changing trends of imaginary and real part of eigenvalues of the focus. Last, the suprathreshold bursting is induced by strong stimulation from the stable focus near big homoclinic orbit, resembling that observed in the experiment. The bursting exhibits “suprathreshold resonance” similar to those evoked near Hopf bifurcation corresponding to type II excitability. A novel condition for “suprathreshold resonance” and the underlying codimension-2 bifurcations are acquired. The results present the comprehensive viewpoints on the subthreshold resonance and extend the condition for the “suprathreshold resonance”, which are helpful for deep understanding resonance in the brain or motor neurons with $$I_{{\text {h}}}$$ current.

Cholinergic receptor-independent modulation of intrinsic resonance in the rat subiculum neurons through inhibition of hyperpolarization-activated cyclic nucleotide-gated channels.

Acetylcholine release is vital in the pacing of theta rhythms in the hippocampus. The subiculum is the output region of the hippocampus with different neuronal subtypes that generate theta oscillations during arousal and rapid eye movement sleep. The combination of intrinsic resonance in the hippocampal neurons and the periodic excitation of hippocampal excitatory and inhibitory neurons by cholinergic pathway drives theta oscillations. However, the acetylcholine mediated effect on intrinsic subthreshold resonance generating hyperpolarization-activated cyclic nucleotide-gated current, Ih of subicular neurons is unexplored. We studied the acetylcholine receptor-independent effect of cholinergic agents on the intrinsic properties of subiculum principal neurons and the underlying mechanism. We bath perfused acetylcholine or nicotine on rat brain slices in the presence of synaptic blockers. The physiological effect was studied by cholinergic fibres stimulation and electrophysiological recordings under whole-cell mode of subiculum neurons using septohippocampal sections. Exogenously applied acetylcholine in the presence of atropine affected two groups of subicular neurons differently. Acetylcholine reduced the resonance frequency and Ih in bursting neurons, whereas these properties were unaffected in regular firing neurons. Subsequently, the endogenously released acetylcholine by stimulation showed a selective suppressive effect on Ih , sag, and resonance in burst firing among the two excitatory neurons. Nicotine suppressed the Ih amplitude in burst firing neurons, which was evident by decreased sag amplitude and resonance frequency and increased excitability. Our study suggests cell type-specific acetylcholine receptor-independent shift in resonance frequency by partially inhibiting HCN current during high cholinergic inputs.

Modeling Reveals Human-Rodent Differences in H-Current Kinetics Influencing Resonance in Cortical Layer 5 Neurons.

While our understanding of human neurons is often inferred from rodent data, inter-species differences between neurons can be captured by building cellular models specifically from human data. This includes understanding differences at the level of ion channels and their implications for human brain function. Thus, we here present a full spiking, biophysically detailed multi-compartment model of a human layer 5 (L5) cortical pyramidal cell. Model development was primarily based on morphological and electrophysiological data from the same human L5 neuron, avoiding confounds of experimental variability. Focus was placed on describing the behavior of the hyperpolarization-activated cation (h-) channel, given increasing interest in this channel due to its role in pacemaking and differentiating cell types. We ensured that the model exhibited post-inhibitory rebound spiking considering its relationship with the h-current, along with other general spiking characteristics. The model was validated against data not used in its development, which highlighted distinctly slower kinetics of the human h-current relative to the rodent setting. We linked the lack of subthreshold resonance observed in human L5 neurons to these human-specific h-current kinetics. This work shows that it is possible and necessary to build human-specific biophysical neuron models in order to understand human brain dynamics.

Energies and widths of Efimov states in the three-boson continuum

Three-boson Efimov physics is well known in the bound-state regime, but far less in the three-particle continuum at negative two-particle scattering length where Efimov states evolve into resonances. They are studied solving rigorous three-particle scattering equations for transition operators in the momentum space. The dependence of the three-boson resonance energy and width on the two-boson scattering length is studied with several force models. The universal limit is determined numerically considering highly excited states; simple parametrizations for the resonance energy and width in terms of the scattering length are established. Decreasing the attraction, the resonances rise not much above the threshold but broaden rapidly and become physically unobservable, evolving into subthreshold resonances. Finite-range effects are studied and related to those in the bound-state regime.

Asymptotic normalization coefficients from transfer reactions and R -matrix analysis of direct capture in the Ne22(p,γ)Na23 reaction

The $^{22}$Ne(p,$\gamma$)$^{23}$Na reaction in NeNa cycle plays an important role in the production of only stable sodium isotope $^{23}$Na. This nucleus is processed by the NeNa cycle during hot bottom burning (HBB) in asymptotic giant branch (AGB) stage of low metallicity intermediate mass stats (4 M$_O$ $\leq$ M $\leq$ 6 M$_O$). Recent measurements have addressed the uncertainty in the thermonuclear reaction rate of this reaction at relevant astrophysical energies through the identification of low lying resonances at E$_p$ = 71,105, 156.2, 189.5 and 259.7 keV. In addition, precise measurements of low energy behaviour of the non-resonant capture has also been performed and the contribution of the sub-threshold resonance at 8664 keV excitation in $^{23}$Na has been established. Here, in this article, we have presented a systematic R-matrix analysis of direct capture to the bound states and the decay of the sub-threshold resonance at 8664 keV to the ground state of $^{23}$Na. A finite range distorted wave Born approximation (FRDWBA) calculation has been performed for $^{22}$Ne($^3$He,d)$^{23}$Na transfer reaction data to extract the asymptotic normalization coeeficients (ANC-s) required to estimate the non-resonant capture cross sections or astrophysical S-factor values in R-matrix analysis. Simultaneous R-matrix analysis constrained with ANC-s from transfer calculation reproduced the astrophysical S-factor data over a wide energy window. The S$_{tot}^{DC}$(0) = 48.8$\pm$9.5 keV.b compares well with the result of Ferraro, {\it et al.} and has a lower uncertainty. The resultant thermonuclear reaction is slightly larger in 0.1 GK $\le$ T $\le$ 0.2 GK temperature range but otherwise in agreeent with Ferraro, {\it et al.}.

Resonant reactions of astrophysical interest studied by means of the Trojan Horse Method. Two case studies

Resonant reactions in astrophysics play and important role as un- expected resonances may enhance the astrophysical factor with respect to the direct reaction contribution, altering the predicted nucleosynthesis scenarios by changing, for instance, the expected nucleosynthesis path. They also are of great interest in nuclear structure studies, since the determination of energies, spin-parities and partial widths sheds light on the occurrence of cluster structures, for instance. However, nuclear reactions in most astrophysical environments usually take place at energies below about 1 MeV, leading to an exponential de- crease of the cross sections due to the effect of the penetration of the Coulomb barrier. Also, at energies so low to be comparable with those associated to elec- tronic degrees of freedom, the effect of atomic and/or molecular clouds cannot be neglected, resulting in a shielding of nuclear charges and in an enhancement of the cross sections with respect to the case of bare nuclei (the so called elec- tron screening effect). Owing to vanishingly small cross sections and ambigui- ties in the extrapolation due to the electron screening, supplying accurate cross sections for astrophysical modeling is extremely challenging. Indirect methods have been introduced to explore the energy range of astrophysical interest with no need of extrapolation, even guided by theoretical arguments. In particular, the Trojan Horse Method makes use of quasi-free reactions with three particles in the exit channel,a+A ^ c + C + s,to deduce the cross section of the reaction of astrophysical interest,a + x ^ c + C,under the hypothesis thatAshows a strongx+scluster structure. Even if measurements are carried out above astro- physical energies to be free from Coulomb suppression and electron screening, the range of astrophysical interest can be covered thanks to the x - s intercluster motion and binding energy. In these proceedings we will show the application of the THM, in the case of resonant reactions, using the generalised R-matrix approach introduced by A.M. Mukhamedzhanov. We will discuss the possibil- ity to extract resonance parameters from the Trojan Horse data and perform a full spectroscopic study of low-energy and even sub-threshold resonances. In particular, we will focus on the19F(p, a)16O and the13C(a, n)16O reactions, of particular importance in the case of asymptotic giant branch stars and in the synthesis of heavy elements by means of the s-process.

Modulation of Frequency Preference in Heterogeneous Populations of Theta-resonant Neurons

Neurons from several brain regions resonate in the theta frequency range (4–12 Hz), displaying a higher voltage response to oscillatory currents at a preferred ‘resonant’ frequency (fR). Subthreshold resonance could influence spiking and contribute to the selective entrainment of neurons during the network oscillatory activity that accompanies several cognitive processes. Neurons from different regions display resonance in specific theta subranges, suggesting a functional specialization. Further experimental work is needed to characterize this diversity and explore how frequency preference could be dynamically modulated. Theoretical studies have shown that the fine-tuning of resonance depends in a complex way on a variety of intrinsic factors and input properties, but their specific influence is difficult to dissect in cells. We performed slice electrophysiology, dynamic clamping and modelling to assess the differential frequency preference of rat entorhinal stellate neurons, hippocampal CA1 pyramidal neurons and cortical amygdala neurons, which share a hyperpolarization-activated current (Ih)-dependent resonance mechanism. We found heterogeneous resonance properties among the different types of theta-resonant neurons, as well as in each specific group. In all the neurons studied, fR inversely correlated with the effective input resistance (Rin), a measurable variable that depends on passive and active membrane features. We showed that resonance can be adjusted by manipulations mimicking naturally occurring processes, as the incorporation of a virtual constant conductance or cell depolarization, in a way that preserves the fR-Rin relationship. The modulation of frequency selectivity influences firing by shifting spike frequency and timing, which could influence neuronal communication in an active network.

Stochastic point process models for multi-compartment dendritic-tree input-output transformations in spiking neurons.

We extend stochastic point-process generalized linear models (PPGLMs) to the estimation of input-output transformations in dendritic trees and their contribution to the generation of soma action potentials in multi-compartmental models of single neurons. We used simulations of a model enthorinal cortex pyramidal neuron, with known dentritic tree and soma spatial organization, including active compartments defined in terms of standard cable and standard Hodgkin-Huxley equations. Each dendritic compartment (391 total) was endowed with either excitatory (E) or inhibitory (I) synaptic inputs whose strength was randomly specified. We examined the cases of both homogeneous and inhomogeneous spatial distributions for E and I synaptic inputs. The times for synaptic inputs followed a Poisson process with different mean rate regimes varying from 50 to 600 inputs/s. The soma membrane potential received also a background noise in the form of an Ornstein-Uhlenbeck process. Our main findings are: (1) Power spectra of soma membrane potentials revealed subthreshold resonances at ~40 Hz and ~80 Hz; (2) The contribution of different dendritic compartments, under the examined input ranges and spatial distributions, depended not only of the dendrite-soma path distance, but also on the number of compartments in the dendritic segment. (3) Estimated conditional intensity functions (CIFs) with PPGLMs successfully predicted spiking activity based on given E-I input times; area under ROC curves computed on test data varied from 0.8 - 0.95. (4) The CIF models identified compartments and regions receiving E-I synaptic inputs; Estimated temporal filters were consistent with dendrite-soma path distances and input weights. We expect this type of PPGLMs to contribute to data-driven identification of input-output transformations in dentritic trees based on single-neuron Ca2+ and voltage indicator imaging data.

Astrophysical SE2 factor of the C12(α,γ)O16 reaction through the C12(B11,Li7)O16 transfer reaction

The ${}^{12}\mathrm{C}(\alpha,\gamma){}^{16}\mathrm{O}$ reaction plays a key role in the evolution of stars with masses of $M >$ 0.55 $M_\odot$. The cross-section of the ${}^{12}\mathrm{C}(\alpha,\gamma){}^{16}\mathrm{O}$ reaction within the Gamow window ($E_\textrm{c.m.}$ = 300 keV, $T_\textrm9$ = 0.2) is extremely small (about $10^{-17}$ barn), which makes the direct measurement in a ground-based laboratory with existing techniques unfeasible. Up until now, the cross-sections at lower energies can only be extrapolated from the data at higher energies. However, two subthreshold resonances, located at $E_x$ = 7.117 MeV and $E_x$ = 6.917 MeV, make this extrapolation more complicated. In this work, the 6.917 MeV subthreshold resonance in the ${}^{12}\mathrm{C}(\alpha,\gamma){}^{16}\mathrm{O}$ reaction was investigated via the ${}^{12}\mathrm{C}({}^{11}\mathrm{B},{}^{7}\mathrm{Li}){}^{16}\mathrm{O}$ reaction. The experiment was performed using the Q3D magnetic spectrograph at the HI-13 tandem accelerator. We measured the angular distribution of the ${}^{12}\mathrm{C}({}^{11}\mathrm{B},{}^{7}\mathrm{Li}){}^{16}\mathrm{O}$ transfer reaction leading to the 6.917 MeV state. Based on the FRDWBA analysis, we derived the asymptotic normalization coefficient (ANC) of the 6.917 MeV level in $^{16}$O to be (1.10 $\pm$ 0.29) $\times 10^{10}$ fm$^{-1}$, with which the reduced $\alpha$ width was computed to be $18.0\pm4.7$ keV at the channel radius of 6.5 fm. Finally, we calculated the astrophysical $S_{E2}(300)$ factor of the ground-state transitions to be 46.2 $\pm$ 7.7 keV b. The result for the astrophysical $S_{E2}(300)$ factor confirms the values obtained in various direct and indirect measurements and presents an independent examination of the most important data in nuclear astrophysics.

Synchronization of Electrically Coupled Resonate-and-Fire Neurons.

Electrical coupling between neurons is broadly present across brain areas and is typically assumed to synchronize network activity. However, intrinsic properties of the coupled cells can complicate this simple picture. Many cell types with electrical coupling show a diversity of post-spike subthreshold fluctuations, often linked to subthreshold resonance, which are transmitted through electrical synapses in addition to action potentials. Using the theory of weakly coupled oscillators, we explore the effect of both subthreshold and spike-mediated coupling on synchrony in small networks of electrically coupled resonate-and-fire neurons, a hybrid neuron model with damped subthreshold oscillations and a range of post-spike voltage dynamics. We calculate the phase response curve using an extension of the adjoint method that accounts for the discontinuous post-spike reset rule. We find that both spikes and subthreshold fluctuations can jointly promote synchronization. The subthreshold contribution is strongest when the voltage exhibits a significant post-spike elevation in voltage, or plateau potential. Additionally, we show that the geometry of trajectories approaching the spiking threshold causes a "reset-induced shear" effect that can oppose synchrony in the presence of network asymmetry, despite having no effect on the phase-locking of symmetrically coupled pairs.