Can a plaintiff make a cognizable claim in an amended complaint alleging that officials deliberately deprived him of his right to exercise his Eighth Amendment rights?

If plaintiff can identify the correct defendants, he may be able to state a potentially cognizable claim that officials were deliberately indifferent to his serious medical needs in violation of plaintiff's Eighth Amendment rights. Plaintiff is advised that in order to state a claim in an amended complaint, he must identify as a defendant only persons who personally participated in a substantial way in depriving plaintiff of a federal constitutional right. Johnson v. Duffy, 588 F.2d 740, 743 (9th Cir. 1978) (a person subjects another to the deprivation of a constitutional right if he does an act, participates in another's act or omits to perform an act he is legally required to do that causes the alleged deprivation).