Transduction Transduction is the process that converts one form of physical energy, such as light, to another form, such as neural impulses. Afferent systems are the sensory systems that process information coming into the brain. Efferent systems are the motor systems that process information going out from the brain to the muscles and glands. Psychophysics is the study of correlations between physical stimuli and the behavior or mental experiences they evoke. Gustav Fechner was a German was a German physicist who coined the term psychophysics.
Absolute threshold is the minimum amount of physical energy needed to produce a sensory experience.
Difference threshold is the smallest physical difference between two stimuli that can still be recognized as a difference. Sensory adaptation refers to the diminishing responsiveness of sensory systems to prolonged stimulus input. The pupil is the opening in the iris, and the lens focuses light on the retina. The retina is the light-sensitive layer of cells at the back of the eye. Photoreceptors are neurons that absorb light and convert it into neural responses.