Thanks to Homer Simpson and George Costanza, researchers in Israel and the US have a better grip on how memories are created and how they can be restored in patients with degenerative brain diseases, like Alzheimer’s and Parkinson’s.
A study by Professor Itzhak Fried to be presented at a symposium in Jerusalem Monday shows how individual memory neurons act when they are “remembering.” The study provides “a rare opportunity to see how neurons, the basic units of cognition, work during the act of recall,” allowing scientists to effectively be able to “see” human memory recall in action in real time, said Fried.
The work, said Fried and his Israeli-American team, gives researchers a clearer picture of how memory recall works and has important implications for understanding dementia such as Alzheimer’s, in which fragments of memory seem to disintegrate over time.
Fried, head of functional neurosurgery at the Tel Aviv Medical Center (Ichilov Hospital) and a professor of neurosurgery at Tel Aviv University’s Sackler Faculty of Medicine and at the University of California Los Angeles (UCLA), will present his findings at a special symposium dedicated to memory set to take place Monday.
Sponsored by the Israel Academy of Sciences and Humanities, the symposium, called “Memory – Past and Future: Recollection, Forgetting and Imagining in the Individual and Society,” will see dozens of the top experts in the field of memory gather in Jerusalem to discuss how memory works, and what its prospects are given the cross-cultural concerns over the loss of our memory skills due to the technological revolution, according to Academy head Professor Nili Cohen.
The conference, she said, is part of “the ongoing and fruitful research between Israelis scientists and researchers and those from around the world in the area of memory science.”
Science, she said, bridges gaps between countries and “is an international language that is based on cooperation between researchers,” she said.
The event is noteworthy in that it is taking place in Jerusalem during a period when tension, both political and security, is rife. Among the speakers will be Prof. Yossi Mathias, vice president for engineering at Google and head of Google’s R&D Center in Israel, and Prof. Pierre Nora, a member of the French Academy of Sciences.
In the study to be presented at the event, Fried and his colleagues were able to monitor subjects’ brain activity as electrodes recorded the activity of individual neurons during brain procedures (the research was done with the subjects’ permission). Such research can only be done on humans, who, unlike animals, are able to verbalize what they are recalling.
The neurons studied by the team are located in the hippocampus. This is the area of the brain affected in Alzheimer`s patients, and it is critical for memory formation and recall. A small part of the brain shaped like a sea horse, the hippocampus stores short-term “episodic” memories — not long-term memories of childhood, but memories like what an individual ate for breakfast. Loss of function in this area of the brain in Alzheimer’s patients explains why they become disoriented in familiar surroundings, said Fried.
In the study, Fried and his team observed the neural activity in the brains of 13 epilepsy patients as they watched clips from TV shows like “Seinfeld” and “The Simpsons.” Shortly afterwards, the test subjects were asked to describe what they remembered from the video clips. As they were recalling what they had seen, the exact same neurons that had become activated when they watched a clip fired up once again.
Soon, the researchers were able to predict what clip the subjects would recall just by looking at the neurons that lit up seconds before the recall experience was vocalized, and they were able to prompt memory recall by stimulating those neurons electrically. The neurons associated with the new memory – which in individuals with degenerative brain disorders might not “stick” and immediately become inactive – spring back to life when the memory is recalled, either spontaneously or with the help of an electric stimulus, the research showed.
According to the team, the study provided an “unprecedented” opportunity to “see” real human memory recall in action.
“It’s unique because we’re able to look at single cells in the brain when people spontaneously retrieve something from inside their memory without any cue from outside,” added Fried.
Much more work is needed in the area, said Fried. He plans further studies to continue research that will give science a better understanding of how memories are formed – especially how associations are formed and then retrieved from the hippocampus.
“The emergence of memory, a trace of things past, into human consciousness is one of the greatest mysteries of the human mind,” he said.
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