Complex sentence: Professor Nathaniel Kleitman and his student Eugene Aserinsky defined rapid eye movement and linked it to dreams in 1953 and further described by researchers including William Dement and Michel Jouvet.
Split into simpler sentences: Professor Nathaniel Kleitman and his student Eugene Aserinsky defined rapid eye movement and linked it to dreams in 1953. REM sleep was further described by researchers including William Dement and Michel Jouvet.