Pioneering neuroscientist who studied the neurobiological mechanisms of perception and memory. He was born in Fitchburg, MA, USA on December 13, 1926, and died in Bethesda, MD, USA on October 2, 2021, at the age of 94.
When neuroscientist Mortimer Mishkin joined the National Institute of Mental Health (NIMH) in Bethesda, Maryland, USA in 1955, he was nearing his 30th birthday. Six decades later, at the age of 90, he retired emeritus. “I don’t know how a scientist could think of retiring earlier,” he once said. “Just for the sake of the process, we’re sticking to it as long as possible.” It was his role as head of the neuropsychology lab that kept Mishkin at NIMH for so long. But while brain research has traditionally focused on the functions of its individual areas, Mishkin has taken a different approach. He saw the functioning of the brain as dependent on the links between these areas: on the functioning of circuits and systems rooted in neuroanatomy. “In some ways it seems obvious today,” says Richard Saunders, senior scientist at NIMH. But, he adds, when Mishkin started working, it was far from obvious. Betsy Murray, now head of the NIMH neuropsychology lab, agrees. “It is difficult to go back to the 1950s, when Mort was still beginning his career, and to understand the impact of his discoveries.
That Mishkin has contributed so much to psychology is all the more remarkable considering the start of his career. “I left high school before I graduated in 1944 to become a Navy aviator,” he told an interviewer in 2011. “When, after a year, the Navy determined that it had enough airmen, I was sent to Dartmouth to become a supply corps officer. He graduated from Dartmouth College in 1947 with a degree in business administration. After leaving the US Navy, he moved to Canada with the intention of doing a doctorate in social psychology at McGill University on the grounds that “the world needed help in solving social problems”. First, however, he had to learn something about psychology itself. Mishkin’s imagination was on fire to ask McGill’s Donald Hebb, a pioneer in explaining cognitive processes in terms of connections between assemblies of neurons; he abandoned thoughts of social psychology. With his doctorate completed, he moved to NIMH and began his own exploration of brain function.
One of Mishkin’s early successes was in memory. “To understand how memory works, you need to understand how sensory information, such as visual information, enters the memory system,” says Saunders. “Mort was the one who really explained how these systems were connected and interacted. He designed experiments to show the importance of these interactions. Saunders recalls the 1978 publication of Mishkin’s findings on memory in monkeys. “He showed that if two structures in the medial temporal lobe, the amygdala and the hippocampus, were both removed, it produced a huge impairment in the monkey’s memory.” Just removing one or the other of the pair didn’t have such an effect. “He really moved forward in understanding the neural substrates of memory,” says Murray.
Mishkin also worked on the vision. He and NIMH colleague Leslie Ungerleider jointly demonstrated the existence of two cortical visual pathways, anatomically and functionally separated. One, the occipito-temporal circuit, dealt with the recognition of objects; the other, the occipito-parietal route, concerned the spatial location of the object. The kind of tracing experiments by which neuroanatomists can now track nerve pathways in the brain were not available to Mishkin who had to rely on more laborious methods. But his pioneering work, says Saunders, “guided other studies of visual function for decades.”
Saunders attributes much of Mishkin’s success to his sheer tenacity: “He was in the lab every day until he was 90. Murray talks about Mishkin’s persistence. “He had very strong assumptions about how the brain worked,” she says, “and that kept him moving forward. But he would never rush into the impression. “Mort was meticulous in analyzing the data,” says Saunders. “He wouldn’t post anything until he was sure what was going on.” Saunders adds that Mishkin never made enemies. “If another investigator found a different result… he would go to that person and say, ‘Let’s do the experiment. [together] and answer the question. It was his approach. Mishkin leaves behind a wife, Barbara, stepchildren, Amy, David, Diane and Paul, and her daughters, Wendy and Susie, and stepdaughters, Roberta and Patricia, from a previous marriage.
Posted: 20 November 2021
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