Which statement best defines transduction in vision?

Which statement best defines transduction in vision?

• A. It is the transmission of visual information from the retina to the brain without any change in potential.
• B. It is the absorption of photons by photoreceptors with no electrical change.
• C. It is the activation of cortical processing without retinal input.
• D. It is the conversion of a physical stimulus (light) into a change in membrane potential or neurotransmitter release.

Answer: (D)

Transduction in vision is the conversion of light into a neural signal. In the retina, photons are absorbed by photopigments in rods and cones, triggering a biochemical cascade that changes the photoreceptor’s membrane potential and alters neurotransmitter release onto bipolar cells. This receptor potential and the accompanying change in glutamate release are the signals that retinal circuits use to encode light information and pass it toward the brain. The essential idea is that a physical stimulus (light) is transformed into a neural signal, not simply transmitted unchanged or processed without retinal input.

Transduction in vision is the conversion of light into a neural signal. In the retina, photons are absorbed by photopigments in rods and cones, triggering a biochemical cascade that changes the photoreceptor’s membrane potential and alters neurotransmitter release onto bipolar cells. This receptor potential and the accompanying change in glutamate release are the signals that retinal circuits use to encode light information and pass it toward the brain. The essential idea is that a physical stimulus (light) is transformed into a neural signal, not simply transmitted unchanged or processed without retinal input.