An apparatus for concurrent electrical stimulation and electrical recording in a human or non-human subject, the apparatus coupleable to an electrode array comprising a plurality of electrodes, the apparatus comprising: a plurality of stimulation circuits selectively coupleable to the plurality of electrodes, each stimulation circuit responsive to a control signal of a first plurality of control signals to provide a stimulation current on a selected first electrode (150 A) of the plurality of electrodes; and a plurality of recording circuits; characterised in that the apparatus also comprises a plurality of blocking circuits, each blocking circuit of the plurality of blocking circuits coupled to a respective recording circuit of the plurality of recording circuits and further coupleable to a corresponding electrode of the plurality of electrodes, each blocking circuit of the plurality of blocking circuits responsive to a corresponding control signal of a second plurality of control signals to selectively either: couple the respective recording circuit to the corresponding electrode to generate corresponding recorded data from that electrode; or block current on the electrode from the respective recording circuit; whereby concurrently with the stimulation current on the selected first electrode (150 A), the blocking circuit coupled to the first electrode (150 A) is responsive to the corresponding control signal of the second plurality of control signals to block the stimulation current from the respective recording circuit and one or more blocking circuits coupled to electrodes (150 1 - 150 N-2) that are different from the first electrode (150 A) are responsive to one or more corresponding control signals of the second plurality of control signals to selectively couple the respective recording circuit to the corresponding electrode thereby enabling simultaneous generation of recorded data from the electrodes (150 1 - 150 N-2) of the plurality of electrodes that are different from the first electrode (150 A). a plurality of stimulation circuits selectively coupleable to the plurality of electrodes, each stimulation circuit responsive to a control signal of a first plurality of control signals to provide a stimulation current on a selected first electrode (150 A) of the plurality of electrodes; and a plurality of recording circuits; characterised in that the apparatus also comprises a plurality of blocking circuits, each blocking circuit of the plurality of blocking circuits coupled to a respective recording circuit of the plurality of recording circuits and further coupleable to a corresponding electrode of the plurality of electrodes, each blocking circuit of the plurality of blocking circuits responsive to a corresponding control signal of a second plurality of control signals to selectively either: couple the respective recording circuit to the corresponding electrode to generate corresponding recorded data from that electrode; or block current on the electrode from the respective recording circuit; couple the respective recording circuit to the corresponding electrode to generate corresponding recorded data from that electrode; or block current on the electrode from the respective recording circuit; whereby concurrently with the stimulation current on the selected first electrode (150 A), the blocking circuit coupled to the first electrode (150 A) is responsive to the corresponding control signal of the second plurality of control signals to block the stimulation current from the respective recording circuit and one or more blocking circuits coupled to electrodes (150 1 - 150 N-2) that are different from the first electrode (150 A) are responsive to one or more corresponding control signals of the second plurality of control signals to selectively couple the respective recording circuit to the corresponding electrode thereby enabling simultaneous generation of recorded data from the electrodes (150 1 - 150 N-2) of the plurality of electrodes that are different from the first electrode (150 A).