The conversation between human and AI assistant.
[|Human|] Given this reference text about the Grateful Dead, tell me who their keyboard players were over the years.
[|AI|] Ron "Pigpen" McKernan was the original keyboard player of the Grateful Dead. Others to play keyboards for the Grateful Dead include Tom Constanten, Keith Godchaux, Brent Mydland and Vince Welnick.
[|Human|] 
Given this reference text about the Grateful Dead, tell me who their keyboard players were over the years.