18 years ago, Henry walked home from the park. A cyclist hit him and knocked him to the ground. Shortly after the accident, he began to have epileptic symptoms.
As time goes on, seizures become more and more serious. By the age of 27, he had suffered from severe epilepsy, sometimes uncontrollable seizures many times a day. He is very weak, and no treatment is effective for him. Dr William Beecher scovill, a famous neurosurgeon, suggested that he should undergo experimental brain surgery, hoping to cure epilepsy by removing deep brain structures.
By today's standards, it was a terrible frontal lobectomy. Dr. scovill removed Henry's tonsils and an important part of the hippocampus, the medial part of the temporal lobe. At that time, Henry was sitting in the operating chair under anesthesia, but he was awake.
After the operation, Henry will amuse himself by playing jigsaw puzzles in the hospital. It's just that he will repeat the same action over and over again, but he doesn't know he has done it. His epilepsy was cured, but his world was completely overturned. He can no longer form a memory for more than 30 seconds. In the next 50 years, H.M. volunteered to spend countless hours doing his tests, becoming the most researched and famous patient in the history of neuroscience.
Interestingly, his other mental functions, such as language and IQ, have not been affected. He still remembers what happened before the operation. His world knowledge, or semantic knowledge, is useful. But he couldn't tell what happened at a specific time or place; He lost his memory of the scene.
This shows that there are different memory systems that support autobiographical memory (unique events that occur at a specific time and place) and another memory system that supports "theme" knowledge. In an amazing experiment, Henry Morrison can remember some famous people in the postoperative period. It is speculated that these people's emotional influence on him helped his memory stay in his mind.
Dr brenda milner, a psychologist at McGill University, made a famous experiment. In this experiment, HM learned to track the stars reflected in the mirror. This is a breakthrough result, because it shows that his motor memory is complete. Studies have proved that declarative memory formed in hippocampus is separated from motor skills. That's why when you learn how to ride a bike, you won't really forget it, unlike the fact.
Henry's amygdala injury did affect other behaviors. In particular, he seems to be out of touch with his inner state. He doesn't seem to feel hunger, fear or pain.
Although he has serious memory problems, he is not helpless. He has been very happy. He is still working, though in a special center. However, there are some tragic stories in his life. He can't remember when his father died. Day after day, he couldn't remember whether his parents were still alive. He writes notes to remind himself that sometimes reading these notes will bring him new sadness. It's like finding that sad news over and over again.
His case completely changed our understanding of memory. We now know that memory is processed by special brain regions and divided in the brain. The ability to form new long-term memories is located in the hippocampus. Another breakthrough contribution is that different parts of the brain have different types of memories. Henry Morrison died in 2008. He donated his brain to the scientific community. Professor Susanna Koldin has been studying it for decades. She assembled a team of scientists and nuclear magnetic resonance experts to conduct an autopsy on Moram.
From June, 5438 to February, 2009, Jacopo Annese of the Brain Observatory of the University of California, San Diego and his team dissected H.M., cut the American brain into 240 1 thin tissue slices, and then preserved them at low temperature in turn. His brain generated the first open, high-resolution three-dimensional atlas of the human brain. [4] [5]
When slicing the brain, the researchers collected digital images of the surface of the brain block, corresponding to each tissue slice. These images are used to construct a three-dimensional microscope model of the whole brain.