Dr. Patty Barker is Royal the dog's therapist on "Castle" in season 4 in the episode "An Embarrassment of Bitches". Dr. Barker had a weekly appointment with Francisco Pilar on his calendar and had been seeing Pilar's dog Royal for years. Her treatment involved close interaction with Royal, going as far as getting down on the floor and rolling around with him. She generally shows more concern and empathy for the dog than for the fact that his human master has been murdered.