. 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
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. Electrophysiology of the Neuron
: 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.
When a neuron receives enough stimulation, it reaches a critical "threshold" (around It maintains a , typically around )
: Sodium channels close and potassium channels open, allowing K+cap K raised to the positive power to exit and bringing the voltage back down.
Researchers use several cutting-edge techniques to "listen" to these electrical conversations: Unlocking Brain Function, One Neuron at a Time When a neuron receives enough stimulation, it reaches
: The voltage briefly dips below the resting level before stabilizing.
