Brain-Chip Interfaces: The Present and The Future

Brain-chip-interfaces (BCHIs) are hybrid entities where chips and nerve cells establish a close physical interaction allowing the transfer of information in one or both directions. Typical examples are represented by multi-site-recording chips interfaced to cultured neurons or implanted in the brain to record or stimulate neuronal excitation. We provide an overview on recent achievements in the field of BCHIs leading to enhancement of signals transmission from nerve cells to chip or from chip to nerve cells, either in terms of signal-to-noise ratio or of spatiotemporal resolution. Micro-nail shaped microelectrodes engulfed by neurons in culture establish a tight electrical coupling with the cells and allow for high signal-to-noise ratio recording. Oxide-insulated chips, featuring large-scale and high-resolution arrays of stimulation and recording elements, represent a promising technology for high spatiotemporal resolution interfacing, as recently demonstrated by recordings obtained from hippocampal slices and brain cortex in implanted animals. Although most BCHIs deal with electrical signals, chemical signaling has also to be considered and some new advances in this direction are reported. Finally, we present and discuss important challenges for design and fabrication of new generations of BCHIs.