What process describes the conversion of physical stimuli into signals in the nervous system?

The process that describes the conversion of physical stimuli into signals in the nervous system is sensation. Sensation refers to the initial detection and encoding of environmental stimuli by sensory receptors. This process involves various sensory modalities, such as vision, hearing, touch, taste, and smell, where physical energy (like light or sound waves) is transformed into neural signals that the brain can interpret.

For example, when light enters the eye, photoreceptors in the retina convert that light into electrical signals, which are then transmitted via the optic nerve to the brain for further processing. This essential first step allows us to become aware of our surroundings and is foundational for subsequent perception, where these sensations are organized and interpreted into meaningful experiences.

Understanding sensation is crucial as it lays the groundwork for how we interact with the world, and it's distinct from other processes, such as perception, which involves interpretation and meaning-making from these sensory inputs. Appraisal and response are also different processes related to how we evaluate stimuli and react to them, respectively, but they do not pertain to the initial conversion of stimuli into neural signals.