As a neuroscientist with a focus on cellular and molecular neuroscience, I can explain the concept of the threshold of excitation in neurons. The threshold of excitation, also simply referred to as the threshold, is a critical value that a neuron's membrane potential must reach in order to trigger an action potential. This is a fundamental concept in understanding how neurons communicate with each other through electrical signals. In most neurons, the threshold is typically around -55mV to -65mV. When the membrane potential of a neuron reaches this level, it indicates that the cell has reached a state of sufficient depolarization to initiate an action potential. An action potential is characterized by a rapid depolarization, during which the membrane potential becomes less negative (or more positive), followed by a slight reversal of the usual membrane polarization. This process involves the opening and closing of ion channels, which allows for the flow of ions like sodium (Na+) and potassium (K+) across the neuron's cell membrane. read more >>

Threshold of excitation(threshold): The level that a depolarization must reach for an action potential to occur. In most neurons the threshold is around -55mV to -65mV. 4. Action potential: A rapid depolarization and slight reversal of the usual membrane polarization.read more >>