compund action potential

compund action potential - negative pulse in recorded...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
As action potentials propagate along an axon, they produce electric potentials that can be recorded from the surface of the nerve. When a nerve bundle is stimulated, many axons produce action potentials synchronously. The resulting electric responses recorded from the surface of the nerve are called compound action potentials to distinguish them from the action potentials generated by individual axons. Compound action potentials can be measured as shown in Figure 3. Stimulus electrodes are applied to one end of the nerve; recording electrodes are located along the nerve. If the nerve is stimulated with a current pulse of sufficient amplitude, the action potentials produced in the fibers propagate toward the recording electrodes. The aggregate effect of the many action potentials is an extracellular wave of negative potential, moving along the surface of the nerve. If the recording electrodes are widely spaced (Figure 3, left panel), the wave of negative potential produces a
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: negative pulse in recorded voltage _ _ _ _ as it passes the recording electrode. At a later time, the negative wave of extracellular potential passes the _ recording electrode, where it contributes a positive pulse to the recorded voltage _ _ _ _ . If the electrodes are more closely spaced (center panel), the negative and positive parts of the recorded voltage _ _ _ _ merge, and the resulting waveform is called a diphasic compound action potential . The propagation can be blocked by a number of methods including mechanical methods (pressure applied to the nerve or crushing the nerve with forceps), electrical methods (passing a blocking level of current through the nerve), or chemical methods (applying potassium chloride, local anesthetics, cocaine, or tetrodotoxin to the nerve)....
View Full Document

This note was uploaded on 03/24/2012 for the course BIOLOGY 102 taught by Professor Steven during the Fall '11 term at Birmingham UK.

Ask a homework question - tutors are online