In physiology, transduction is the conversion of a stimulus from one form to another.
Transduction in the nervous system typically refers to stimulus alerting events wherein a mechanical/physical/etc stimulus is converted into an action potential which is transmitted along axons towards the central nervous system where it is integrated.
For example, in the visual system, sensory cells called rod and cone cells in the retina convert the physical energy of light signals into electrical impulses that travel to the brain. The light causes a conformational change in a protein called rhodopsin. This conformational change sets in motion a series of molecular events that result in a reduction of the electrochemical gradient of the photoreceptor. The decrease in the electrochemical gradient causes a reduction in the electrical signals going to the brain. Thus, in this example, more light hitting the photoreceptor results in the transduction of a signal into fewer electrical impulses, effectively communicating that stimulus to the brain.
In the olfactory system, odorant molecules in the mucus bind to G-protein receptors on olfactory cells. The G-protein activates a downstream signalling cascade that causes increased level of cyclic-AMP (cAMP), which trigger neurotransmitter release. [1]
In neuroanatomy, sensory transduction is the process in which a receptor cell converts the energy in a stimulus into a change in the electrical potential across its membrane.[2] It causes the membrane to depolarize and allows the neuroimpluse to be transducted to the brain for integration.