2019 Honorable Mention – Allison Thabit

Action Potential

by Allison Thabit: Composer/Performer | Christian Charley: Producer/Audio Engineer

Action Potential

Action Potential is the phenomenon of how neurons transmit signals from one neuron to the next. Before a neuron receives a signal, there is high concentration of dissolved sodium ions outside the cell membrane of the neuron, and a high concentration of potassium ions on the inside. When the dendrite of a pre-ganglionic neuron receives a chemical signal at the synapse, the post-ganglionic neuron creates opens the channels that allow these ions to travel through the cell membrane. Positively charged potassium ions are pumped out of the cell, while negatively charged sodium ions are let into the cell. These processes are not happening at the same rate, and rely on different cell “machinery” to happen.

The inside of the cell is relatively negative in comparison to the outside. The cell starts out as mostly neutrally charged both inside and directly outside of the cell membrane, but as more ions are pumped in and out, the electrical charge of the cell becomes more and more polarized. When this polarization reaches a certain threshold, the cell “fires” an electrical signal from the cell body, down the axon, and to the axon terminal, where it is again converted into a chemical signal to be received by the next neuron. This is called the all or nothing response; if the threshold is never reached, the signal is never sent.

The piece has 5 parts, all performed individually but compiled and stacked on top of each other to become an ensemble. Different parts play different “roles” in terms of being harmonic or melodic, while others establish rhythm or textural context. I wrote this piece with the specific intention of performing all of the parts separately, and knew that Christian’s skill as a producer would help bring the piece together. We did our best to make it sound as if an ensemble were playing, and worked to bring out the different and interesting bits of each part while maintaining the blend of the “ensemble.” The piece almost linearly follows the timeline of action potential, starting from a “resting” neuron that isn’t receiving a signal, receiving a signal and building tension (electronegativity) and then quickly releasing the electrical signal down the axon. The piece ends as it started, a neuron at rest.