These implants could help us unlock the secrets of the human brain

To understand how the brain works—or doesn’t, as the case may be—depends on deciphering the patterns of electrical signals its neurons produce. Recording them requires inserting electrodes into the tissue. But the rigid devices traditionally used to record these signals, or to therapeutically stimulate certain regions, can damage the brain and elicit an immune response, and they tend not to work for very long. Now researchers have shown that a new type of flexible electronic device, which can be delivered via injection, could be a gentler alternative. In the near term, the technology could yield valuable insights about how the electrical activity of certain circuits, or networks of neurons, is related to discrete functions, like the creation of a lasting memory. It could also shed light on the brain’s dysfunctions, like schizophrenia or Parkinson’s disease (see “Cracking the Brain’s Codes” and “Shining a Light on Madness”). Further down the road, the concept could lead to a better way to deliver therapeutic stimulation to address neurodegenerative diseases, or a stable brain-computer interface that might help disabled people do things their condition usually wouldn’t allow them to do, like move prosthetic limbs or communicate (see “The Thought Experiment”).