“…For clinical practice in the context of the brain, such technologies typically involve arrays of a few tens of electrodes that interface with the skin of the scalp or the surface of the brain to capture spatiotemporal variations in electrical potential, through techniques known as electroencephalography (EEG) and electrocorticography (ECoG), respectively (Figure a). These devices can provide essential information for investigating and diagnosing degenerative conditions such as Parkinson’s − and Alzheimer’s diseases − and also various neurological disorders such as Zika virus induced microcephaly − and epilepsy. , The resulting signals can also be used as brain–machine interfaces to control prosthetics and other external devices. , As sources of electrical stimulation, the electrodes can activate or inactivate targeted neural networks to eliminate seizures and tremors. , In rehabilitation, related types of stimulation can modulate cortical excitability in stroke patients to enhance the effects of training for various tasks associated with daily life. , In the context of research, neural interfaces can be applied in wide-ranging animal models for fundamental studies. For in vitro experiments that use human induced pluripotent stem cells (hiPSCs), these technologies can be used to explore drugs, , genetic diseases, , and cancers. , Here, electrophysiological measurements − occur with multielectrode arrays (MEAs) , and patch clamps , for thin films of cells (Figure b).…”