The role of nicotinic acetylcholine receptors in the medial prefrontal cortex and hippocampus in trace fear conditioning

► Nicotine in the dorsal hippocampus enhances trace and contextual fear conditioning. ► Nicotine in the ventral hippocampus disrupts trace and contextual fear conditioning. ► Nicotine in medial prefrontal cortex enhances trace but not contextual conditioning. ► Nicotinic antagonists in medial prefrontal cortex enhance trace fear conditioning. ► Trace and contextual fear conditioning involve different substrates.