Complex sentence: The nucleus paragigantocellularis (nPGi), located in the rostral ventral medulla, is a key brainstem region involved in the expression of cardiovascular and respiratory changes that occur following sympathetic activation.
Split into simpler sentences: The nucleus paragigantocellularis (nPGi) is a part of the brain, located in the rostral ventral medulla. It is a key brainstem region involved in the expression of cardiovascular and respiratory changes that occur following sympathetic activation.