A Toronto man whose brain was among the most studied in the world has died.
He was known in his many appearances in the scientific literature as simply K.C., an amnesiac who was unable to form new memories. But to the people who knew him, and the scientists who studied him for decades, he was Kent Cochrane, or just Kent.
Cochrane, who suffered a traumatic brain injury in a motorcycle accident when he was 30 years old, helped to rewrite the understanding of how the brain forms new memories and whether learning can occur without that capacity.
"From a scientific point of view, we've really learned a lot [from him], not just about memory itself but how memory contributes to other abilities," said Shayna Rosenbaum, a cognitive neuropsychologist at York University who started working with Cochrane in 1998 when she was a graduate student.
Cochrane was 62 when he died late last week. The exact cause of death is unknown, but his sister, Karen Casswell, said it is believed he had a heart attack or stroke. He died in his room at an assisted living facility where he lived and the family opted not to authorize an autopsy.
Few in the general public would know about Cochrane, though some may have seen or read media reports on the man whose life was like that of the lead character of the 2000 movie Memento. But anyone who works on the science of human memory would know K.C.
Casswell and her mother, Ruth Cochrane, said the family was proud of the contribution Kent Cochrane made to science. Casswell noted her eldest daughter was in a psychology class at university when the professor started to lecture about the man the scientific literature knows as K.C.
"She was quite thrilled to say 'That's my uncle."'
In the scientific literature Cochrane followed in the footsteps of an American man known as H.M., who had sustained similar brain damage in 1953 when he underwent a lobotomy that was supposed to ease his severe epilepsy.
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The surgery left H.M. incapable of making new memories. A book on his much-studied life called "Permanent Present Tense: The Unforgettable Life of the Amnesic Patient, H.M." was published last year by Suzanne Corkin.
Morris Moscovitch, a senior scientist at Baycrest Hospital's Rotman Research Institute in Toronto, also worked extensively with K.C. He said something Corkin said of H.M. also pertains to Cochrane.
"She says in the book [that] … H.M., despite not knowing it, led a very meaningful life. More meaningful than probably most of our lives. And I think the same could be said of K.C. His contribution gave meaning to his life and to his parents' lives."
Moscovitch first learned of Cochrane's case in 1983 when one of his undergraduate students declared he'd met a man who suffered from the same kind of memory deficits as the by-then famous H.M. The student worked at a sheltered workshop and had met Cochrane there.
Reimagining past impossible
Testing showed that Cochrane was indeed unable to form new memories or recollect events from before his motorcycle crash. He knew facts about himself, but could not draw up the rich memories that other people have. So, for example, he could look at a picture and recognize the people in it. He might even know that the photo was of a Christmas when he was a child. But he would not have been able to remember if the sweater he was wearing was a Christmas present, or anything that might have happened that day.
As Moscovitch puts it, Cochrane couldn't reimagine his past experiences. And, the scientists who worked with him learned, he was not able to imagine a future. Before K.C., it was not known that remembering past experiences and imaging future ones were governed by the same part of the brain.
Moscovitch said Cochrane contributed "tremendously" to the ongoing efforts to tease out the mysteries of what the various parts of the brain do, and what happens when those parts sustain damage.
By studying Cochrane, scientists were able to determine that the hippocampus was crucial for this kind of memory and thinking. Humans have two hippocampi, seahorse-shaped portions of the brain that are nestled under the cerebral cortex in the front of the brain.
Learn through repetition
"That idea that the hippocampus is necessary for reliving the past rather than just knowing about it has become a central contribution of Kent," Moscovitch said.
Though he couldn't form new memories, Cochrane could learn, with repetition. Moscovitch noted testing showed Cochrane was "quite bright" and that intellect hadn't been destroyed by his brain damage.
For instance, his family devised a system to let Cochrane know what was up if he found himself at home alone. Because of his memory deficit, his parents could tell him they were going out and a few minutes later he would not recollect that information. When that happened, he knew to check the refrigerator door; there would be a message for him there. And he learned how to refile books at the library where he worked.
"He was able to pick up information and automatically store it and retrieve it, both action-based things and perceptually based knowledge," said Moscovitch, though he noted that while Cochrane could do this type of task by rote, he could not remember being taught these skills.
"He'd be able to learn these strategies with repetition, but often wasn't aware where he acquired the strategy or how he acquired it."
Rosenbaum said Cochrane is the subject of at least 32 scientific papers, with five more in the publication pipeline. In fact, just days before Cochrane's sudden death, Rosenbaum learned that another research paper focused on him was accepted for publication. As well, she said, countless literature reviews and studies mention K.C. or were influenced by his case.
"He inspired I would say almost every paper I've written since [graduate school.] Even though he wasn't necessarily the subject of every paper, he was a very great influence," said Rosenbaum, who is also an associate scientist at the Rotman Research Institute.
She described Cochrane as gentle, kind and even keeled.
"Despite everything he was just a very warm and very pleasant person to be around," Rosenbaum says. "I felt as though he was just a real source of light in general."
Cochrane was predeceased by his father, Irving, and one brother. He is survived by his mother, Ruth, a retired nurse, two brothers, his sister and numerous nieces, nephews, grandnieces and grandnephews.