Question 1. You want to study the passive electrical properties of an axon from

Question

Question 1. You want to study the passive electrical properties of an axon from a newly characterized type of neuron. You inject current to induce a 10 mV depolarization at one end of the axon, and you measure the resulting depolarization at different points along the axon. Shown here is the trace of measured depolarization along the axon as a function of distance from the current injection. 10.0 90 7.0 6.0 5.0 4.0 8 3.0 2.0 1.0 0.0 a. (1 pt) What is the approximate value of the length constant? 00 10 20 3.0 5.0 6.0 Distance (mm) b. (1 pt) What is the approximate value of the depolarization at a distance of two length constants from the location of applied voltage?

Explanation / Answer

a)The fall of voltage in a neuron can be given by the formula:

Vx = Vmax (e-x/)

In this formula, Vx = current voltage; Vmax = maximum voltage (in mV); x = distance from start of potential; = length constant (in mm)

Applying this formula to the overall equation:

Vx = 3.5mV; Vmax = 10mV; x = 1mm;

3.5/10 = e-x/ = 0.35; loge (0.35) = 1/

= (1/0.456) = 2.2 mm

b) If x = 2 length constants i.e. 2 * 2.2 = 4.4mm

then, approximate value of Vx = 0

Related Questions

Navigate

• Browse (All)
• Browse Q
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.