Cortical stimulator
The cortical stimulator was a medical device used to revive neural activity in the nervous system of critical patients by delivering an electrical shock to induce brain activity. It was almost always attached to the temples or foreheads of humanoids. Cortical stimulators were standard equipment in the sickbays of Starfleet vessels in the 24th century. 

In 2154, Captain Jonathan Archer used a cortical stimulator, as directed by Phlox, in a vain attempt to revive Hoshi Sato. ()

In 1986, while back in time from the 23rd century, Doctor Leonard McCoy used a cortical stimulator to revive Commander Pavel Chekov after the latter fell down an elevator shaft trying to escape from security on the aircraft carrier . Chekov was taken to Mercy Hospital and the doctors unsuccessfully tried to drill into his head via Fundoscopic examination. Dr. McCoy arrived in time to revive Chekov and helped him escape from the hospital. ()    

In 2364, Doctor Beverly Crusher used a cortical stimulator in a vain attempt to revive Lieutenant Natasha Yar after she was struck down by Armus. ()

In 2368, Crusher attempted to revive Captain Jean-Luc Picard with a cortical stimulator following his exposure to the Kataan probe. The stimulator's interruption of the beam from the Kataan probe caused Picard to go into neural shock, which only stabilized when the cortical stimulator was removed. The probe later disengaged the beam safely, and Picard recovered without further intervention, though the probe made him live fifty years of another being's life in approximately twenty real-time minutes. ()

In 2369, Dr. Crusher used it to revive Counselor Deanna Troi after temporarily inducing clinical death to break a telepathic bond that was sapping her life force to keep Federation mediator Ves Alkar artificially young. ()

Later that year, Picard again had to be revived with cortical stimulators after an energy blast on an away mission damaged his artificial heart. ()

Soon after, Crusher used cortical stimulators in an attempt to revive Jo'Bril after he had been subjected to baryon radiation. ()

In 2370, Dr. Julian Bashir revived Quark with a cortical stimulator after he suffered extensive neural trauma from being shot. ()

In 2371, The Doctor treated Tuvok with a cortical stimulator after he was felled by hallucinations stemming from the presence of tachyons. ()

Soon after, The Doctor used two cortical stimulators to return Commander Chakotay's bio-neural energy to his body in sickbay. ()

In 2372, The Doctor attempted to revive Crewman Kurt Bendera with a cortical stimulator. It was unsuccessful and he was pronounced dead soon after. ()

That same year Quark was again in Dr. Bashir's infirmary with a stimulator on his head after Brunt and his Nausicaan thugs beat him to a pulp inside his bar fallowing Rom's strike. Quark also had a shattered eye socket, two broken ribs, and a punctured left lung. (DS9:"Bar Association") 

In 2373, The Doctor also used one on Tuvok when he suffered a t'lokan schism ()

Later that year, The Doctor used a cortical stimulator on Captain Kathryn Janeway when she suffered a near-fatal injury. ()

In 2375, The Doctor on the Silver Blood  used a cortical stimulator on B'Elanna Torres' duplicate, but failed to save her. ()

Later that year, Neelix used a cortical stimulator on Pelk when he went into shock. ()

de:Kortikalstimulator
Medical equipment