The Spark of Life: Electrophysiology of the Neuron At its core, the brain is an electrical machine. While we often think of thoughts as abstract, they are physically powered by the movement of charged ions across cellular membranes. is the study of these electrical properties, allowing us to understand how cells communicate, how disorders arise, and how the brain processes information . The Resting State: A Battery Ready to Fire

A neuron at rest is like a charged battery. It maintains a , typically around

). This triggers an , a rapid spike in electrical activity that travels down the axon.

: Sodium channels close and potassium channels open, allowing K+cap K raised to the positive power to exit and bringing the voltage back down.

. This negative charge inside the cell is created by an imbalance of ions—specifically sodium ( Na+cap N a raised to the positive power ) and potassium ( K+cap K raised to the positive power )—regulated by specialized pumps and channels. The Action Potential: The "All-or-Nothing" Signal

This process is "all-or-nothing"—the signal doesn't get "stronger" with more stimulus; instead, the neuron fires more frequently . How We Study the Brain's Electricity