Key points from article :
DARPA is funding research into "mind control" chips.
Closed loop brain implants use artificial intelligence to detect mood disorders.
Electric shocks automatically jolt a person's brain back to a healthy state.
Shocks can also improve performance in some tasks.
Already tested on 6 patients with epilepsy.
Ethical concerns that technology exposes person's inner feelings.
The study was published in the Nature journal.
