**Core Concept**
Zaleplon is a non-benzodiazepine hypnotic agent used for the short-term treatment of insomnia. Its pharmacological action involves modulating the activity of the neurotransmitter GABA (gamma-aminobutyric acid), which is an inhibitory neurotransmitter in the brain.

**Why the Correct Answer is Right**
Zaleplon selectively binds to the alpha-1 subunit of the GABA_A receptor, a subtype of GABA receptors. This binding results in an increase in the activity of GABA, leading to sedation and anxiolysis. Zaleplon's rapid onset and short duration of action make it ideal for treating insomnia without leading to residual sedation or dependence. Its elimination half-life is approximately 1 hour, which contributes to its short-acting nature.

**Why Each Wrong Option is Incorrect**
**Option A:** Zolpidem is a non-benzodiazepine hypnotic agent, but it has a longer duration of action compared to Zaleplon. Zolpidem's elimination half-life is approximately 2.5-3 hours.
**Option C:** Zopiclone is a cyclopyrrolone, a class of non-benzodiazepine hypnotics that act on the GABA_A receptor. However, Zopiclone has a longer duration of action compared to Zaleplon and is not considered a short-acting agent.
**Option D:** Midazolam is a benzodiazepine, not a non-benzodiazepine sedative. While Midazolam is used for sedation, its pharmacological profile and duration of action are different from those of Zaleplon.

**Clinical Pearl / High-Yield Fact**
Zaleplon is unique among non-benzodiazepine hypnotics due to its rapid onset and short duration of action, making it an excellent choice for treating insomnia in patients who require a short-term solution. However, it is essential to note that Zaleplon is not recommended for long-term use due to concerns about tolerance and dependence.

**✓ Correct Answer: B. Zaleplon**