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
). This triggers an , a rapid spike in electrical activity that travels down the axon. Electrophysiology of the Neuron
: The voltage briefly dips below the resting level before stabilizing. : The voltage briefly dips below the resting
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 is the study of these electrical properties, allowing
: Voltage-gated sodium channels snap open, allowing Na+cap N a raised to the positive power to flood into the cell, making it more positive.
. 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
: Sodium channels close and potassium channels open, allowing K+cap K raised to the positive power to exit and bringing the voltage back down.