An implantable sensor array incorporates active electronic elements to greatly increase the number of sensors and their density that can be simultaneously recorded and activated. The sensors can be of various configurations and types, for example: optical, chemical, temperature, pressure or other sensors including effectors for applying signals to surrounding tissues. The sensors/effectors are arranged on a flexible and stretchable substrate with incorporated active components that allow the effective size, configuration, number and pattern of sensors/effectors to be dynamically changed, as needed, through a wired or wireless means of communication. Active processing allows many channels to be combined either through analog or digital means such that the number of wires exiting the array can be substantially reduced compared to the number of sensors/effectors on the array.