Self-modeling structure of evoked postsynaptic potentials

Abstract

With the simplicity of the synaptic structure and physiology at neuromuscular junctions (NMJs) of crayfish and the given transmitter being released in quantal packets, a detailed assessment in the fundamental processes of chemical synaptic transmission is possible. Since the quantal event is the basic element of transmission, we consider an approach to further understand the characteristics of quantal responses. In this study, we introduce a method for combining information across excitatory postsynaptic potentials (EPSPs) that are quantal in nature. The method is called self-modeling regression, known in the statistics literature as SEMOR. This method illustrates that the differing timing and heights of EPSPs can be described with four coefficients measuring affine (shift and scale) transformations of the x and y axes. We demonstrate that this relationship allows us to provide a unified schema for the many functionals currently used in the literature, such as peak amplitude, tau, latency, area under the curve, or decay time. Computer code in R is available on the internet to perform the analysis.

Historical View and Physiology Demonstration at the NMJ of the Crayfish Opener Muscle

“…The excitor motor neuron that innervates the entire opener muscle also innervates the stretcher muscle in a more proximal leg segment. Facilitation measurements between muscle fibers of the opener muscle showed that there are differences which may be related to resting levels in Ca2+ ions (Cooper et al, 2005b) and/or possibly cooperatively of release (Parnas et al, 1982a,b) The differences in structural complexity among high-and low-output synapses along the terminals on the opener muscle were investigated for quantal signatures with respect to recruitment of active zones among synapses during STF but this has proven to be difficult to ascertain (Lancaster et al, 2007;Viele et al, 2003Viele et al, , 2006. Possible the pools of vesicles among high-and low-output synapses will prove to be regulated differentially in kinetics as it is known neromodulators have differential effects on low and high-output terminals ( The future use of the opener muscle preparation in crayfish is as rich as it has been 50 or a 100 years ago.…”

Mixtures of Self-Modelling Regressions

“…This method is utilized in previous work [10]. This forces the scaling on g to follow the chosen function but allows BARS to run unconstrained.…”

“…Thus, we begin by taking the functions ( ) m k g across the iterations and aligning them to each other. This was done via a Procrustes registration as in previous work [10]. The base shape function of this alignment was used as the estimate for g k .…”

“…The motor nerve is repeatedly stimulated and the synaptic response is monitored as described previously in work by two of the authors [10]. With low frequency stimulation of this low output NMJ, occasionally an evoked response is observed.…”

“…The details of this fit, which simply assumed known knots for a spline fit to g, are described in previous work [10]. This fit accounts for over 96% of the variation in the dataset.…”