Which of the following option would not associated with a decrease in conduction velocity of a nerve impulse in a neuron :-

Options

A. Increasing the length of the axon
B. Removing the myelin sheath
C. Cooling the axon
D. Increasing pressure on axon

Answer

To solve the question regarding which option would not be associated with a decrease in conduction velocity of a nerve impulse in a neuron, we can analyze each option systematically.

### Step-by-Step Solution:

1. **Understanding Nerve Conduction Velocity**:
- Nerve conduction velocity refers to the speed at which an electrochemical impulse travels along a neuron. This speed can be influenced by various factors.

2. **Evaluating Each Option**:
- **Option A: Increasing the length of the axon**:
- Longer axons can lead to slower conduction due to increased resistance. However, if the diameter of the axon is also increased, it can enhance conduction. Generally, longer axons do not inherently decrease conduction velocity.

- **Option B: Removing the myelin sheath**:
- The myelin sheath acts as an insulator and facilitates faster conduction through saltatory conduction. Removing it would indeed decrease conduction velocity.

- **Option C: Cooling the axon**:
- Lower temperatures slow down the biochemical processes involved in impulse conduction, leading to a decrease in conduction velocity.

- **Option D: Increasing pressure on the axon**:
- Increasing pressure on the axon does not directly correlate with a decrease in conduction velocity. It may affect the axon mechanically but does not inherently slow down the nerve impulse.

3. **Conclusion**:
- Based on the evaluations, the option that would **not** be associated with a decrease in conduction velocity is **Option D: Increasing pressure on the axon**.

### Final Answer:
The correct answer is **Option D: Increasing pressure on the axon**.

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