First order neuron in optic pathway is:
**Core Concept**
The optic pathway is a complex neural network responsible for transmitting visual information from the eyes to the brain. The first-order neuron in this pathway is a critical component that plays a key role in the initial processing of visual signals.
**Why the Correct Answer is Right**
The correct answer is the retinal ganglion cell (RGC). RGCs are the first-order neurons in the optic pathway, extending from the retina to the optic disc, where they form the optic nerve. These cells are responsible for transmitting visual information from the retina to the lateral geniculate nucleus (LGN) of the thalamus. RGCs are activated by the bipolar cells, which receive input from photoreceptors (rods and cones) in the retina.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the optic pathway as it is not a neuron involved in visual signal transmission.
**Option B:** This option might seem plausible, but it is not the correct first-order neuron in the optic pathway. The optic nerve is actually formed by the axons of RGCs.
**Option D:** This option is incorrect as it is not a specific type of neuron involved in the optic pathway.
**Clinical Pearl / High-Yield Fact**
RGCs are responsible for transmitting visual information from the retina to the brain, and their damage can lead to visual field defects, such as blindness or loss of peripheral vision.
**Correct Answer:** C.