In recent years scientists have gained the ability to identify where memories are registered in the brains of lab animals. They can manipulate those memories, erase them or even implant new ones. It may now be not too far-fetched an idea to ponder: Could we use such methods in humans, for example, to treat those suffering from PTSD? And if so, should we?
This is one of the questions explored tonight on "Breakthrough: Decoding the Brain," which airs at 9 p.m. ET/8 p.m. CT on National Geographic Channel. Director Brett Ratner and narrator Adrien Brody meet with scientists who are using innovative technologies to develop new treatments for neurological disorders. New tools to explore the brain have also helped scientists begin to unravel profound mysteries such as how memories are made and how the brain gives rise to consciousness.
"Decoding the Brain" is part of "Breakthrough," a series developed by GE and National Geographic Channel. Each episode explores scientific discoveries in brain sciences, longevity, water, energy, pandemics and cyborg technology.
Making and breaking memories
Changing or erasing memories is an old idea. But only in recent years have scientists become able to actually do it, thanks to optogenetics, a relatively new method that allows researchers use light to switch neurons on and off.
Steve Ramirez is a memory researcher at the Massachusetts Institute of Technology who uses optogenetics to study the formation of memories as well as the possibilities for manipulating them. He and his colleagues have been able to erase memories or implant false memories in mice. He hopes this work could help develop new treatments for people suffering from PTSD.
So far, optogenetics has been used only in animals. But if it ever gets translated for use in humans, would it be ethical to use? The toll that a disorder like PTSD takes on a person's quality of life makes memory manipulation an appealing treatment as a last resort.
But being able to directly manipulate memories may have implications beyond just erasing the traumatic ones. What if during the worst moments of your life, you could push a button and watch some memories of happier times? Researchers have shown this could potentially lessen the damage that stressful situations could impose on the brain. In a study published earlier this year in Nature, Ramirez and his colleagues were able to keep track of happy memories as they were being registered in the brain of male mice during flirtation with female mice. Later, they rekindled the memories by activating the neurons holding those memories. The team showed that evoking positive memories made the animals more resilient when they were put under stress and reduced their depression-like behaviors.
A switch for consciousness?
Neurologist Mohamad Koubeissi is the Director of the Epilepsy Center at George Washington University in Washington, DC. His research aims to reduce the occurrence of seizures in people with epilepsy who don't respond to medications. To do this, Koubeissi implants electrodes deep in the brains of patients to control the activity of neurons whose abnormal firing leads to seizures.
Aside from the therapeutic potentials, this research also offers a unique chance for studying long-standing research questions by giving scientists direct access to the brain. And sometimes, it results in surprising discoveries. For example, when evaluating a patient, Koubeissi discovered that stimulating a small area of the brain called the claustrum can result in global disruption of consciousness. The patient had an electrode implanted in the claustrum, and was asked to read something from a book. When Koubeissi turned on electrical stimulation, the patient suddenly stopped reading and stared blankly. She later had no memory of what happened during the stimulation. When the stimulation was turned off, she resumed exactly where she had left off. This finding suggests that the claustrum is connected with other brain regions that together give rise to consciousness.
You can watch Koubeissi and his patient in this video of the first 5 minutes of tonight's episode: