Neuroscience:Single Neuron Dynamics: an Introduction

Neuroscience:Single Neuron Dynamics: an Introduction

This chapter discusses the mathematical descriptions of neuronal behavior. The potential in the bath surrounding a neuron is relatively constant under normal circumstances, and it is conventionally taken to be zero. The potential inside the cell is then, by definition, the membrane potential. It can be measured by inserting a hollow glass electrode filled with an electrolytic solution through the cell membrane. At rest, the membrane potential is typically around −70 mV and during the normal course of cell activity, it may vary from about −80 mV to +50 mV. These variations are caused by changes in the conductances of channels that allow ions to cross the cell membrane. The neuron is polarized at rest because of its negative membrane potential. Making the membrane potential more negative is termed hyperpolarization and moving it in the positive direction is termed depolarization. The electrical currents that affect the membrane potential of a neuron arise from the flow of ions, principally potassium, sodium, calcium, and chloride, across the cell membrane.