What is rheobase and chronaxie?

What is rheobase and chronaxie?

Rheobase—The minimum current required to depolarize a nerve given an infinite duration of stimulation. Chronaxie—The duration of current required to depolarize a nerve to threshold when the current is two times the rheobase.

How do you calculate rheobase and chronaxie?

The Chronaxie is a duration measurement, corresponding to twice the Rheobase. From the graph above, the Rheobase is approximately 0.64 volts, and the Chronaxie is about 0.16 ms….

How is chronaxie measured?

To measure the chronaxie and rheobase, we applied pulses with varying amplitudes of voltage and varying pulse durations, and then looked for the minimal voltage that elicited excitation in 50% of the neurons in the disconnected network at every pulse duration.

What do you mean by chronaxie?

The chronaxie is defined as the pulse duration required for excitation when the current amplitude is equal to twice the rheobase current.

What do you mean by rheobase?

In neuroscience, rheobase is the minimal current amplitude of infinite duration (in a practical sense, about 300 milliseconds) that results in the depolarization threshold of the cell membranes being reached, such as an action potential or the contraction of a muscle.

How do you determine rheobase?

As you said, the criterion for the rheobase is that it is the minimum current at which the cell generates an action potential (after a long duration) All currents you inject lead to the generation of an action potential, so the rheobase is lower than 300 pA (around 100 pA guessing from the curvature of the black trace) …

What muscle has highest chronaxie?

Among the different types of muscle tissue, skeletal striated muscles have the briefest chronaxie. The chronaxie of the heart muscle is more prolonged, and that of the smooth muscles is the most prolonged.

What is the difference between rheobase and threshold?

The threshold , or minimal stimulus , is defined as “the electrical stimulus whose strength (or voltage) is sufficient to excite the tissue. Rheobase is defined as “the minimum strength (voltage) of stimulus which can excite the tissue”.

Why is chronaxie important?

Significance. The main value of chronaxie is comparing excitability across different experiments and measurements using the same standard, thus making data comparisons easier. Electrical stimulation based on chronaxie could regulate myoD gene expression in denervated muscle fibers.

Why is chronaxie shorter in red muscles?

The pale muscle fibres (more active) have shorter chronaxies than the red muscles (sluggish). Fatigue lengthens and adrenaline shortens the chronaxie of skeletal muscles. Similarly, cold lengthens and warm shortens it.

What is Rheobase electrophysiology?

Rheobase is defined as the current amplitude of infinite duration needed to depolarize the membrane potential to threshold for action potential generation.

Why chronaxie is 1 ten times more in skeletal muscles of infants than in the skeletal muscles of adults?

Chronaxie is 10 times more in skeletal muscles of infants than in the skeletal muscles of adults. It is longer in paralyzed muscles than the normal muscle. And, in progressive neural diseases, chronaxie is prolonged gradually. Chronaxie is shortened by increased temperature and prolonged in cold temperature.

What is the meaning of chronaxie?

[French : Greek khronos, time + Greek axiā, value (from axios, worthy; see ag- in Indo-European roots).] chronaxie. chronaxy. (Physiology) physiol the minimum time required for excitation of a nerve or muscle when the stimulus is double the minimum (threshold) necessary to elicit a basic response.

What is the meaning of chronia?

A measurement of excitability of nervous or muscular tissue; the shortest duration of an effective electrical stimulus having a strength equal to twice the minimum strength required for excitation. Synonym(s): chronaxia, chronaxis, chronaxy. [G. chronos, time, + axia, value]

What is the difference between rheobase and chronaxie?

Rheobase and chronaxie are points defined on the strength-duration curve for stimulus of an excitable tissue. Chronaxie is the minimum time required for an electric current double the strength of the rheobase to stimulate a muscle or a neuron. Rheobase is the lowest intensity with indefinite pulse duration which just stimulated muscles or nerves.

What are the values of chronaxie?

Values. Chronaxie is derived from the strength-duration curve for current and it shows that if the stimulus duration is shorter than chronaxie, more current is required to stimulate, with any type or location of electrodes with a stimulator of any known or unknown output impedance. In addition, the chronaxie value, however determined,…