Abstract: The present disclosure relates to an array of electrodes on a flexible scaffolding, with the ability to collapse into an axial configuration suitable for deploying through a narrow cylindrical channel. The electrode arrays can be placed into the ventricular system of the brain, constituting a minimally invasive platform for precise spatial and temporal localization of electrical activity within the brain, and precise electrical stimulation of brain tissue, to diagnose and restore function in conditions caused by abnormal electrical activity in the brain.