Recording electrophysiological events from thousands of neurons in parallel is now routine in neuroscience, but almost all of this population-scale recording is done extracellularly, from outside the cell membrane. Seen from outside, the signal is attenuated: large spikes come through, but the subtler events such as synaptic signals are too weak to detect, even though they carry much of the brain’s computation. We build silicon chips that reach the full range. Belonging to the same family as the microprocessors in computers and phones but outfitted with specially engineered surface microelectrode arrays, these chips make intimate contact with living cells and perform population-scale recording from many neurons extracellularly by default, crossing into the intracellular regime when an electronic intervention coaxes the cell to effectively let the electrode in. We call this class of devices the intracellular microelectrode array (iMEA): a platform that adds an intracellular recording modality to the traditional extracellular one, both at population scale. By opening access to the inside of the cell across populations, these interfaces can reach farther, where conventional tools cannot.