Direct amygdala stimulation can enhance human memory for a day

Health-4.jpg

DIRECT electrical stimulation of the human amygdala, a region of the brain known to regulate memory and emotional behaviors, can enhance next-day recognition of images when applied immediately after the images are viewed, neuroscientists have found.
The findings are the first example of electrical brain stimulation in humans giving a time-specific boost to memory lasting more than a few minutes, the scientists say. Patients’ recognition only increased for stimulated images, and not for control images presented in between the stimulated images. The experiments were conducted at Emory University Hospital in 14 epilepsy patients undergoing intracranial monitoring, an invasive procedure for the diagnosis of seizure origin, during which electrodes are introduced into the brain.
“We were able to tag specific memories to be better remembered later,” says co-first author Cory Inman, PhD, postdoctoral fellow in the Department of Neurosurgery. “One day, this could be incorporated into a device aimed at helping patients with severe memory impairments, like those with traumatic brain injuries or mild cognitive impairment associated with various neurodegenerative diseases. However, right now, this is more of a scientific finding than a therapeutic one.”
“We see this as a platform for the further study of memory enhancement,” says senior author Jon T. Willie, MD, PhD, assistant professor of neurosurgery and neurology at Emory University School of Medicine. “The time specificity enables a lot of other experiments, since we know that there’s not a carry-over effect from one image to the next.”
Deep brain stimulation (DBS), with current delivered continuously by an implanted device, is an established clinical method for the treatment of movement disorders such as Parkinson’s disease, and is being tested for psychiatric conditions such as depression. In contrast with DBS’s invasiveness, researchers elsewhere have experimented with non-invasive electrical stimulation as an approach for enhancing memory or cognition, with several rounds of stimulation applied while learning.
“The advantage of DBS is that it can selectively modulate a specific brain circuit without broad off-target effects,” says Willie, who performed surgeries on patients in the study. The amygdala’s key roles in emotional responses and fear-associated learning have been well-studied. So the Emory scientists made sure that amygdala stimulation at low levels of current (0.5 milliamps) did not result in emotional responses, an elevated heart rate, or other signs of arousal.

Share this post

PinIt
    scroll to top