Electrophysiology is the study of the electrical properties and activities of cells and tissues.
It seeks to understand how electrical signals are generated, transmitted, and processed in neurons and neuronal networks.
This knowledge is crucial for understanding brain function and treating neurological disorders.
Electrophysiology focuses on the following key aspects:
1. Ion channels:
Specialized proteins in neuron cell membranes that allow specific ions to pass through and play a critical role in generating and maintaining electrical signals.
2. Resting membrane potential:
The voltage difference across the cell membrane when a neuron is not transmitting a signal, typically around -70 mV.
3. Action potentials:
Rapid, transient changes in membrane potential that serve as the primary means of transmitting information within the nervous system.
4. Synaptic transmission:
Conversion of electrical signals into chemical signals and back into electrical signals at junctions between neurons, involving neurotransmitter release and receptor activation.
5. Neuronal networks:
Complex interconnected circuits of neurons that process and transmit information throughout the nervous system, with a focus on understanding function and adaptability.
Electrophysiological techniques:
To study electrophysiology in the nervous system, several techniques are used, including:
1. Patch clamp:
Records electrical activity of individual ion channels by attaching a glass pipette to the cell membrane.
2. Intracellular recording:
Inserts microelectrode directly into a neuron to record membrane potential and action potentials.
3. Extracellular recording:
Measures electrical activity of a group of neurons using an electrode placed near cells; records local field potentials and single-unit activity.
4. Voltage-sensitive dyes and genetically encoded voltage indicators:
Visualizes electrical activity in neurons using compounds or proteins that change fluorescence in response to membrane potential changes.
5. EEG and MEG:
Non-invasive techniques to measure electrical activity of large neuron populations in the brain via electrodes on the scalp (EEG) or by detecting magnetic fields (MEG).