Neural Electric Activity

Neural electric activity refers to the electrical signals generated by neurons through ionic current flows across their cell membranes. The primary source of EEG signals is the postsynaptic potentials in the dendrites of pyramidal neurons in the cerebral cortex, which create electrical dipoles when activated synchronously.

The magnitude of individual neural signals is typically in the range of microvolts (μV), with action potentials around 70-110 mV and postsynaptic potentials around 0.1-10 mV. When thousands of neurons fire synchronously, their combined activity can be detected at the scalp surface, though significantly attenuated by intervening tissues.

The temporal dynamics of neural electric activity span multiple scales:

• Action potentials: ~1-2 ms
• Postsynaptic potentials: 10-100 ms
• Population oscillations: 100-1000 ms