Consider the following modified logistic equation with a threshold dV dt (1) where t represents time,...
Fantastic news! We've Found the answer you've been seeking!
Question:
Transcribed Image Text:
Consider the following modified logistic equation with a threshold dV dt (1) where t represents time, V is the dependent variable (e.g., voltage) and the function F(V) is given by = F(V) == -r V V V (₁ - 1) (1 - 1) 1 T K F(V) (2) The parameters r, K,T and I are constants, r, K,T > 0 and T < K. The parameter r represents the rate constant (inverse of the time constant for the unbiased case I app 0). The units depend on the problem at hand. If the model is intended for the dynamics of a neuron, then the units of t are milliseconds (ms) and the units of V are millivolts (mV). This equation has many applications. In particular, it can be used to describe the transi- tion of a system from a resting state (Vrest, lower equilibrium Veq) to and activated state (Vact, higher equilibrium Veg), when they exist, through a threshold (Vth, intermediate equilibrium Veg). Vact is also referred to as the saturation value V sat. In the context of neuronal systems, eq. (1) can be used as a (very simple) model of ac- tion potential generation (but not termination) where the occurrence of an action potential + I. = is determined by the transition from Vrest to Vact. In this case, the parameter I is interpreted as the applied current (Iapp) to the neuron (an external DC current that is controlled by the experimenter/modeler). The description of the termination of an action potential is not de- scribed by this model, and requires additional mechanisms and additional model complexity (e.g., a system of two or more differential equations). The existence and values of the equilibria (Vrest, Vth and Vsat) depend on the model parameters (r, T, K and I). For I = 0, eq (1) has three equilibria (Veg): Vrest = 0, Vth = T and Vsat = K. Because of this, T and K are referred as the threshold and carrying capacity, respectively, in the literature. For other values of I, the activity attributes (Vrest, Vth and Vsat are not longer explicitly given by a single parameter (T, K) and the attributes may even cease to exist for certain ranges of values of I (all other parameters fixed). 1. Write a code to solve numerically the ODE (1)-(2) (or adapt the template code provided in the course website). The simulation output for each set of parameter values must be (a) A graph of the solution V(t). (b) The equilibrium value(s) Veq = limt→∞ V(t) (c) A graph of F as a function of V. • Each simulation should be run long enough (large enough value of t) so that V(t) reaches values close enough to Veq, but not too long so the changes in V(t) are clearly shown. . Plot the two graphs as two panels in the same graph. . Use correct labels for the axes. • Use large enough fonts (suggested: "fontsize" - 24) 2. Consider the following parameter values: r = 1, T = 0.25, K = 1. Perform simulations as described above for V(0) = 0.01 and three values of I: I = 0, I = 0.05, I = 0.1. 3. (Undergraduate level) Investigate the behavior of the model in terms of the model pa- rameters (e.g., plot graphs of the dependence of the attributes of activity as a function of the model parameters). Consider the following modified logistic equation with a threshold dV dt (1) where t represents time, V is the dependent variable (e.g., voltage) and the function F(V) is given by = F(V) == -r V V V (₁ - 1) (1 - 1) 1 T K F(V) (2) The parameters r, K,T and I are constants, r, K,T > 0 and T < K. The parameter r represents the rate constant (inverse of the time constant for the unbiased case I app 0). The units depend on the problem at hand. If the model is intended for the dynamics of a neuron, then the units of t are milliseconds (ms) and the units of V are millivolts (mV). This equation has many applications. In particular, it can be used to describe the transi- tion of a system from a resting state (Vrest, lower equilibrium Veq) to and activated state (Vact, higher equilibrium Veg), when they exist, through a threshold (Vth, intermediate equilibrium Veg). Vact is also referred to as the saturation value V sat. In the context of neuronal systems, eq. (1) can be used as a (very simple) model of ac- tion potential generation (but not termination) where the occurrence of an action potential + I. = is determined by the transition from Vrest to Vact. In this case, the parameter I is interpreted as the applied current (Iapp) to the neuron (an external DC current that is controlled by the experimenter/modeler). The description of the termination of an action potential is not de- scribed by this model, and requires additional mechanisms and additional model complexity (e.g., a system of two or more differential equations). The existence and values of the equilibria (Vrest, Vth and Vsat) depend on the model parameters (r, T, K and I). For I = 0, eq (1) has three equilibria (Veg): Vrest = 0, Vth = T and Vsat = K. Because of this, T and K are referred as the threshold and carrying capacity, respectively, in the literature. For other values of I, the activity attributes (Vrest, Vth and Vsat are not longer explicitly given by a single parameter (T, K) and the attributes may even cease to exist for certain ranges of values of I (all other parameters fixed). 1. Write a code to solve numerically the ODE (1)-(2) (or adapt the template code provided in the course website). The simulation output for each set of parameter values must be (a) A graph of the solution V(t). (b) The equilibrium value(s) Veq = limt→∞ V(t) (c) A graph of F as a function of V. • Each simulation should be run long enough (large enough value of t) so that V(t) reaches values close enough to Veq, but not too long so the changes in V(t) are clearly shown. . Plot the two graphs as two panels in the same graph. . Use correct labels for the axes. • Use large enough fonts (suggested: "fontsize" - 24) 2. Consider the following parameter values: r = 1, T = 0.25, K = 1. Perform simulations as described above for V(0) = 0.01 and three values of I: I = 0, I = 0.05, I = 0.1. 3. (Undergraduate level) Investigate the behavior of the model in terms of the model pa- rameters (e.g., plot graphs of the dependence of the attributes of activity as a function of the model parameters).
Expert Answer:
Related Book For
Posted Date:
Students also viewed these accounting questions
-
Describe inventory turnover and how it can be used to manage inventory.
-
Describe how a SWOT analysis can be used to conduct a first-pass assessment of whether an idea is likely to become a viable business opportunity.
-
Describe several methods that can be used to relax constrained resources.
-
Using the following information, determine the activity rate for the quality inspections activity. Budgeted Activity Cost Pool Activity Setups Estimated Activity Base 1,000 $60,000 Purchase orders...
-
Wilkins Food Products, Inc. acquired a packaging machine from Lawrence Specialists Corporation. Lawrence completed construction of the machine on January 1, 2009. In payment for the machine Wilkins...
-
A steel shaft of \(0.05 \mathrm{~m}\) diameter and \(2 \mathrm{~m}\) length is fixed at one end and carries at the other end a steel disc of \(1 \mathrm{~m}\) diameter and \(0.1 \mathrm{~m}\)...
-
Compare and contrast between various valuation methods. Which valuation methods are most appropriate for manufacturing firms and which are the most appropriate for internet-based ventures?
-
Equipment replacement, no income taxes. Pro Chips is a manufacturer of prototype chips based in Dublin, Ireland. Next year, in 2010, Pro Chips expects to deliver 552 prototype chips at an average...
-
You purchase a machine for "$X" and secure a 5 yr contract where that machine produces parts (say plastic handles). One year later, you sell your company for 10 times the original cost of the...
-
Table 1 shows Apple's online orders for the last week. When shoppers place an online order, several "recommended products" (upsells) are shown as at checkout an attempt to upsell See table 2 in cell...
-
2. Consider the following graph and write a java program that will: 4 (b 10 8 7 6 a 9 5 9 8 2 2 C f 1 a. Generate a minimum spanning tree using Prim's algorithm and finally compute the total cost b....
-
True Or False Violation of a statute always imposes an absolute duty of compliance.
-
True Or False Under the common law a plaintiffs complaint survived their death.
-
What are some of the defenses to negligence per se?
-
What is the family-purpose doctrine?
-
True Or False Children who engage in activities reserved for adults are always held to the standard of care of a reasonable adult.
-
An APR of 17% under monthly compounding gives an EAR of____ Note: Show your answer in units of percents, use plain numbers with at least two digits after the decimal (e.g., for 12.34%, type 12.34).
-
The first law of thermodynamics is sometimes whimsically stated as, You cant get something for nothing, and the second law as, You cant even break even. Explain how these statements could be...
-
The current I flowing through a semiconductor diode is given by I = Is(eqvd/kt 1) where Is = 10-12 A is the saturation current, q = 1.6 Ã 10-19 C is the elementary charge value, k = 1.38...
-
The ladder of a fire truck can be elevated (increase of angle ), rotated about the z axis (increase of angle ), and extended (increase of r). Initially the ladder rests on the truck ( > = 0, = 0,...
-
According to special relativity, a rod of length L moving at velocity v will shorten by an amount 8, given by: = L(1 - 1 v2/c2 where c is the speed of light (about 300 x 106 m/s). Consider a rod of...
-
An analysis by Professor Peter M Rothwell and his colleagues (Nuffield Department of Clinical Neuroscience, University of Oxford, UK) published in 2012 in the medical journal The Lancet...
-
Suppose a student is interested in knowing the preferred holiday destinations of the faculty members in their university. They are affiliated to the college of business and interview a few of the...
-
The following table shows the result of the 2018 General Elections in Pakistan, along with the vote share predicted by several organizations in the days before the elections. The sample sizes were...
Study smarter with the SolutionInn App