We talk about the discovery of the enzyme that has an effect on humans’ ability to learn


Alzheimer’s or complete memory loss has become a frequent material for films and stories. Vastly different from everyday forgetfulness, these symptoms are caused by abnormalities in brain cells. Now, Korean scientists have discovered an enzyme essential to learning. Today, we have invited Professor Kaang Bong-kiun강봉균 of the Department of Brain and Cognitive Sciences of Seoul National University to talk about how he and his colleagues unveiled the mysteries of the brain.

The enzyme we discovered is called PI3K Gamma. The PI3K family comes in a variety of forms, such as alpha, beta, delta, and so on. So PI3K gamma is just a member of the PI3K enzyme family. This family of enzymes is involved in immunity, the cardiovascular system and nervous system. Until now, studies have focused on the role of PI3K gamma in immunity and cardiovascular systems, and little was known about what role this enzyme played in the nervous system. What our team did was find out what role this enzyme had in the nervous system.

When describing a smart person, Koreans often say that the person has “a well-functioning brain.” As a matter of fact, there is an enzyme that helps the brain work well, facilitating the movement of neurotransmitters. And that enzyme is PI3K gamma, discovered by Professor Kaang and his colleagues. They confirmed through animal testing that PI3K gamma was key to memory, learning, and judgment.

We were able to produce mice with this enzyme genetically removed. These special mice, in effect, lacked the genes for the PI3K gamma enzyme. We analyzed the brain structure of these mice and found it to be not much different from that of the normal mice. But, there is a part called hippocampus in the brain, which plays an important part in learning and memory. We took out the hippocampus in the PI3K-removed mice and studied how the synapses in the hippocampus worked. As a result, we found out there was a flaw in the workings of synapses in the genetically incomplete mice.

Cognitive flexibility is the reason why we can update our past experiences with new information. Without this ability, our brain cannot learn new information. For instance, we won’t be able to remember our new phone numbers if we didn’t have the ability to complement our memory with new information. Cognitive flexibility has to do with the signal transmission system of neurotransmitters in the brain. When we store new information in our brain, neurotransmitters transmit signals across a synapse, which maintain memory flexibility by increasing or decreasing synaptic formations. In order for new information to take hold in our memory, nerve cells need to be strengthened as well as weakened to erase past information or less useful memories. Professor Kaang found in underwater maze tests that PI3K gamma played an important role in diminishing the synapses. His study is expected to provide new grounds for the development of drugs for Alzheimer’s or other dementia.

Our study found that PI3K gamma played an important role in controlling cognitive flexibility in memory, learning, and judgment. Cognitive flexibility refers to a function vital to human behavior, which is not bound by the memory or decision-making activity based on past experiences, but is shaped by actively incorporating new information from the surrounding environment to form new memories and the spur the learning process. This study is significant in that it provided crucial clues to understanding cognitive control and related molecular mechanism. In particular, it opened new possibilities in boosting memory and cognitive abilities of dementia patients and developing drugs for age-related dementia. Although these findings cannot be immediately applied to drug development, it was confirmed that PI3K gamma is vital to cognitive flexibility, so we are now in the process of finding ways to further stimulate the function of this enzyme.

If the function of PI3K gamma can be stimulated, even dementia patients with diminished cognitive abilities can update their memories with new information. The study can also provide relief to the sufferers of post traumatic stress disorder by showing the way to erase bad memories. To that end, Professor Kaang and his colleagues are working hard to produce a more fine-tuned and effective way to control cognitive flexibility.

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