These 'mind control' chips emit electronic pulses that alter brain chemistry in a process called 'deep brain stimulation.'
If they prove successful, the devices could be used to treat a number of mental health conditions and to ensure a better response to therapy.
The chips are the work of scientists at the Defense Advanced Research Projects Agency (DARPA), a branch of the US Department of Defense which develops new technologies for the military.
Researchers from the University of California (UC) and Massachusetts General Hospital (MGH) designed them to use artificial intelligence algorithms that detect patterns of activity associated with mood disorders.
Once detected, they can shock a patient's brain back into a healthy state automatically.
Experts believe the chips could be beneficial to patients with a range of illnesses, from Parkinson's disease to chronic depression.