Neurophysiology

Neurophysiology is the branch of physiology that studies the functions of the nervous system. It seeks to understand how nerve cells, networks, and circuits produce perception, movement, emotion, and cognition by converting electrical and chemical signals into coordinated activity. The field spans multiple levels of organization, from the properties of individual neurons to the activity of large-scale brain networks that underlie behavior.

Core concepts include resting membrane potential, action potentials, synaptic transmission, and plasticity. Neurons communicate through electrical impulses and chemical synapses, with ion gradients and voltage-gated channels shaping signals. Glial cells also contribute to neural function by supporting metabolism, signaling, and homeostasis. The study of neurophysiology covers how sensory inputs are transformed into neural representations, how motor commands are generated, and how higher cognitive processes emerge from distributed networks.

Common experimental approaches encompass electrophysiology, such as intracellular and patch-clamp recordings to measure membrane currents, and extracellular recordings of action potentials. Techniques like electroencephalography and magnetoencephalography record aggregate neuronal activity, while functional imaging methods such as fMRI and PET infer neural activity from metabolic and hemodynamic signals. Neurochemistry investigates neurotransmitters and receptors, and modern methods like optogenetics and chemogenetics enable causal manipulation of specific neural populations. Computational models are used to simulate neural dynamics and information processing.

Applications include understanding sensory processing, motor control, autonomic regulation, sleep, and cognition, as well as diagnosing and treating neurological disorders. Neurophysiology intersects with neuroscience, psychology, biomedical engineering, and medicine to explain how the nervous system supports behavior and experience.