During the mechanism of vision, the cells which generate the first potential on stimulation be light is/are:

Options

A. Road and cones
B. Bipolar neurons
C. Optic nerve
D. Ganglion cells

Answer

To solve the question regarding the cells that generate the first potential on stimulation by light during the mechanism of vision, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Mechanism of Vision**:
- Vision begins when light enters the eye and reaches the retina, which is the inner layer of the eye responsible for detecting light.

2. **Identifying Key Cell Types in the Retina**:
- The retina contains several types of cells, but the primary cells involved in the initial detection of light are the photoreceptor cells. These are divided into two main types: rod cells and cone cells.

3. **Function of Photoreceptor Cells**:
- Rod cells are sensitive to low light levels and are responsible for night vision (scotopic vision).
- Cone cells are responsible for color vision and function best in bright light conditions (photopic vision). They are concentrated in the fovea, the central part of the retina.

4. **Generation of Action Potential**:
- When light hits these photoreceptor cells, it causes a chemical change in the photopigments (retinal and opsin) within them. This change leads to the generation of an action potential, which is the first electrical signal in the visual pathway.

5. **Conclusion**:
- Since the question asks for the cells that generate the first potential on stimulation by light, the correct answer is the **rod and cone cells**.

### Final Answer:
**Rod and cone cells** generate the first potential on stimulation by light during the mechanism of vision.

---