Detectability of Excitatory versus Inhibitory Drive in an Integrate-and-Fire-or-Burst Thalamocortical Relay Neuron Model

Although inhibitory inputs are often viewed as equal but opposite to excitatory inputs, excitatory inputs may alter the firing of postsynaptic cells more effectively than inhibitory inputs. This is because spike cancellation produced by an inhibitory input requires coincidence in time, whereas an excitatory input can add spikes with less temporal constraint. To test for such potential differences, especially in the context of the function of thalamocortical (TC) relay nuclei, we used a stochastic “integrate-and-fire-or-burst” TC neuron model to quantify the detectability of excitatory and inhibitory drive in the presence and absence of the low-threshold Ca 2+ current, IT, and the hyperpolarization-activated cation conductance, Isag. We find that excitatory inputs are generally superior drivers compared with inhibitory inputs in part because spontaneous activity of a postsynaptic neuron is not required in the case of excitatory drive. Interestingly, the presence of the low-threshold Ca 2+ current, IT in a postsynaptic neuron allows the robust detection of inhibitory drive over a certain range of spontaneous and driven activity, a range that can be extended by the presence of the hyperpolarization-activated cation conductance, Isag. These simulations suggest a possible reinterpretation of the role of inhibitory inputs, such as those to the thalamus

The Potential Benefits of Flexibility for Dissemination and Implementation: Acceptance and Commitment Therapy as an Example

Our commentary on the article by Fixsen and Blase (2018) highlights some of the converging and diverging strategies between the Teaching-Family Model (TFM) and the dissemination and implementation of acceptance and commitment therapy (ACT). We focus primarily on the potential benefits of flexibility in areas including theory, methodology, and intervention protocols. Examples include the use of middle level terms, randomized controlled trial methods, protocols focused more on function than specific topography, and an open, collaborative approach to dissemination. We also note how this broader set of strategies can be made coherent and progressive through a careful connection back to contextual behavioral science as an underlying scientific strategy and its associated philosophy of science. We hope this approach contributes to an ongoing conversation on potentially useful strategies for dissemination and implementation

Mode Locking in a Periodically Forced Integrate-and-Fire-or-Burst Neuron Model

The minimal “integrate-and-fire-or-burst” (IFB) neuron model reproduces the salient features of experimentally observed thalamocortical relay neuron response properties, including the temporal tuning of both tonic spiking (i.e., conventional action potentials) and post-inhibitory rebound bursting mediated by the low-threshold Ca2+ current, IT. In previous work focusing on experimental and IFB model responses to sinusoidal current injection, large regions of stimulus parameter space were observed for which the response was entrained to periodic applied current, resulting in repetitive burst, tonic, or mixed (i.e., burst followed by tonic) responses. Here we present an exact analysis of such mode-locking in the integrate-and-fire-or-burst model under the influence of arbitrary periodic forcing that includes sinusoidally driven responses as one case. In this analysis, the instabilities of mode-locked states are identified as both smooth bifurcations of an associated firing time map and nonsmooth bifurcations of the underlying discontinuous flow. The explicit construction of borders in parameter space that define the instabilities of mode-locked zones is used to build up the Arnol’d tongue structure for the model. The zones for mode-locking are shown to be in excellent agreement with numerical simulations and are used to explore the observed stimulus dependence of burst versus tonic response of the IFB neuron model

An Emerging Integration of Universal and Culturally Specific Psychologies and its Implications for the Study of Psychopathology

There is an emerging consensus among researchers on the need to integrate universal and culturally specific psychological perspectives. Important tasks in this process have included identifying the appropriate level of generality for putatively universal processes, how to understand culturally different processes in light of shared universal capacities, and the development of transparent scientific means for investigating cultural differences. In this chapter, the authors discuss each of these issues. It appears to be true that many psychological processes appear to reflect culturally-specific instantiations of universal capacities. The authors then consider implications of this emerging integration for psychology, by applying it to the study of psychopathology. They report on formal models that explain why some cultures embrace dysfunction among members. They then use the integrative framework to describe methods for determining whether putative disorders bring universal or contextual life dysfunction, and to clarify etiological models of three disorders. Models of psychopathology can be more informed and precise if they include careful consideration of both universal and cultural influences on behavior. Cultural psychology is not a separate discipline within psychology; rather, it informs, and should be integrated with, the various content domains within the field

Cis/trans energetics in epoxide, thiirane, aziridine and phosphirane containing cyclopentanols: Effects of intramolecular OH···O,S,N and P contacts

c 2019 by the authors A recent computational analysis of the stabilizing intramolecular OH···O contact in 1,2-dialkyl-2,3-epoxycyclopentanol diastereomers has been extended to thiiriane, aziridine and phosphirane analogues. Density functional theory (DFT), second-order Møller-Plesset perturbation theory (MP2) and CCSD(T) coupled-cluster computations with simple methyl and ethyl substituents indicate that electronic energies of the cis isomers are lowered by roughly 3 to 4 kcal mol−1 when the OH group of these cyclopentanol systems forms an intramolecular contact with the O, S, N or P atom on the adjacent carbon. The results also suggest that S and P can participate in these stabilizing intramolecular interactions as effectively as O and N in constrained molecular environments. The stabilizing intramolecular OH···O, OH···S, OH···N and OH···P contacts also increase the covalent OH bond length and significantly decrease the OH stretching vibrational frequency in every system with shifts typically on the order of −41 cm−