Complex sentence: Part of the binding studies focused on the 5HT 5A receptor due to the distribution of this receptor in the suprachiasmatic nucleus, a tiny region of the brain, which is implicated in the sleep-wake cycle.
Split into simpler sentences: Part of the binding studies focused on the 5HT 5A receptor, which is distributed in the suprachiasmatic nucleus. This is a tiny region of the brain, which is implicated in the sleep-wake cycle.