Fig. 7. Hardware schemes for flexible connection between electrodes and wires.

a In the current Neuropixels array each electrode can be connected to just one wire with a controllable switch. b Two switches per electrode would allow a choice of 2 wires, enabling many more pooling configurations. c Because neighboring electrodes often carry redundant signals, one may want to choose just one from every group of 4. This switch circuit matches that choice with one of 3 (or no) wires. d An optional inverter for each electrode, controlled by a local switch.