Electrophysiology Techniques

Electrophysiology involves the measurement of current flow or voltage changes inside the ion channels, which are membrane protein complexes that allow the movement of ions across cell membranes. Ion channels are present in the membrane of neurons -- cells that constitute the brain, spinal column and nerves. The opening and closing of ion channels lead to changes in currents across the cell membrane. This current is measured using several electrophysiological techniques.

Current Clamp

• The current clamp is a common electrophysiology technique. The technique helps to study how a cell responds when an electrical current enters it. The technique is important for understanding how neurons respond to neurotransmitters present in the brain. Neurotransmitters are chemical messengers that transmit signals from one neuron to a cell.

Voltage Clamp

• The voltage clamp technique is useful in studying the cells and cell membranes. The voltage clamp measures the amount of current flow across a cell's membrane at any given voltage.

Single Unit Recording

• Single unit recording measures the action potential from a single neuron. Action potential is a change in electrical potential on the surface of a cell that occurs when the cell is stimulated. The technique involves the use of an electrode introduced into the brain. The electrode helps detect the electrical activity generated by the neurons adjacent to the electrode tip. In humans, single unit recording is done before or during brain surgery. The technique helps a neurosurgeon to target exactly the tissue he might wish to remove from the brain of a surgery patient.

Patch-Clamp Technique

• Patch-clamp technique is used to know what's happening in or on a single living cell. The technique uses a glass micropipette --- a glass tube that measures small volumes of liquids. To measure cell activity, the micropipette is placed next to the membrane of the cell and gentle suction is applied through the micropipette. The small patch of cell membrane is displaced into the tip of a micropipette. This patch of cell membrane is used to record the activity of a cell.