The startle reflex and PGO spikes.
D000161:Acoustic Stimulation; D000818:Animals; D002415:Cats; D004569:Electroencephalography; D004576:Electromyography; D004585:Electrooculography; D005071:Evoked Potentials; D005133:Eye Movements; D005829:Geniculate Bodies / Q000502:physiology*; D009778:Occipital Lobe / Q000502:physiology*; D011149:Pons / Q000502:physiology*; D013216:Reflex, Startle / Q000502:physiology*; D012890:Sleep / Q000502:physiology*