Cory Inman has fond memories of tending campfires at boy scout camp in the north Georgia mountains.
As Inman started his postdoctoral fellowship at Emory University, in Atlanta, he began to wonder: If a warm-and-fuzzy event in his distant past could stimulate this particular almond-shaped cluster of neurons in his brain and strengthen memory formation, could an electrode implanted into the brain of someone with cognitive deficits do effectively the same thing?
To find out, Inman and his colleagues at Emory University, in Atlanta—including neurosurgeon Jon Willie and memory researcher Joseph Manns—recruited 14 patients with epilepsy who already had electrodes placed in their brains to detect and monitor seizures.
The researchers sat each person in front of a computer screen and displayed images of everyday objects: celery stalk, clipboard, roller skate, butterfly, skeleton key, telescope, ship-in-a-bottle, basketball, park bench—160 in total.
Half of the time, at random and immediately after seeing the picture for three seconds, participants received a one-second zap of low-amplitude electrical stimulation directly to their amygdalas, delivered in eight short bursts, each 50 Hertz in frequency and at a current of 0.5 milliamp.
That jolt made all the difference on memory tests administered one day later.