Exploring memories with Dr. Morris Moscovitch

FACULTY PROFILE

By Bruna Seixas Lima & Denise DuBois 


 

Attending McGill University at the age of 16 and starting a PhD program at the age of 20 does not make him a prodigy, says Dr. Morris Moscovitch (Moscovitch M 2017, oral communication, 14th February). This may be true. If we were going to verify this, a cross-sectional analysis of the data would have shown that this was partially due to the natural path of the school system in Montreal in the 1960’s. Longitudinally, however, the data that make up his life story show that Dr. Moscovitch is indeed a prodigy.

Dr. Moscovitch was born in Romania and at a young age moved to Israel. Like many before and after him, he came to Canada as a child because his parents thought this would be a better place to live. Like many, he did well at school and went to university, and also like many, Dr. Moscovitch did not always see eye to eye with his supervisor. “My supervisor described the project to me on the board, I still remember this. I said, ‘OK, but what does it mean, why are we doing this?’, and he said ‘Don’t worry Mr. Moscovitch, whichever way the results come out they will be important,’” he explains. “So I said, ‘I don’t really care which way the results come out, I just want to know why I’m doing this’, and that’s when he said ‘Mr. Moscovitch, we are not going to get along’”.

The room fills with laughter.

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Dr. Morris Moscovitch is a Professor of Psychology at the University of Toronto and Senior Scientist at Baycrest Centre for Geriatric Health.

That supervisor was Dr. Donald Hebb, the renowned Canadian psychologist most widely known for the theory of Hebbian learning (1). Hebbian learning is an associative learning theory, which provides a biological basis for methods of education and rehabilitation. This theory is commonly summarized as “cells that fire together, wire together”. Hebb and Moscovitch, however, did not fire together.

“And so I didn’t work with Hebb, but I worked with Peter Milner, which was just fine”. Dr. Peter Milner was one of the scientists involved in the discovery of the reward system in the brain in 1954 (2). He was married to Brenda Milner, another world-renowned Canadian neuropsychologist whose work on memory and the brain has granted her the title of “the founder of neuropsychology” (3). Dr. Moscovitch also worked in Dr. Brenda Milner’s laboratory at the Montreal Neurological Institute.

Evidently, the apple does not fall far from the tree. Having been mentored by some of the most influential scientists in his area and eyewitnessed the rise and development of neuropsychology, Dr. Moscovitch has become a leading figure himself. He has been a professor of Psychology at the University of Toronto since 1971. He is also a Senior Scientist at the Rotman Research Institute of Baycrest Centre for Geriatric Care. There he works exploring the brain mechanisms that mediate cognitive functions, such as memory. His research has been showcased in more than 300 studies and anyone who has had a chance to interact with him is left with the impression that several books could be written with the stories he has to tell.

In one story, Dr. Moscovitch described how a motorcycle accident led him to experience his research in the flesh. Dr. Moscovitch borrowed a small motorcycle “not much bigger than a bike” for a trip to the zoo with a friend. The trip sadly ended with the bike run down by a truck, and Dr. Moscovitch being knocked out and rushed to the hospital. He sustained a concussion that had scrambled the circuitry necessary for forming new memories, Dr. Moscovitch explains. He could not remember the accident or that his friend was with him: “After a little while in the hospital the first thing that I remember is this girl, whose boyfriend’s bike I had managed to get into an accident. I said ‘How did you find out I was here?’ And then she told me, and I said ‘I think I may have asked you this before,’ and she said ‘many times.’ ”

Interestingly, some information was stored, such as negative ‘gut’ feelings about a nurse, he otherwise could not remember: “I turned to my parents and said ‘I don’t know why but I really don’t like that guy. There’s no reason for me not to like him, I never met him before’ and my parents said ‘You met him, he was trying to get you to lie down and be quiet and you kept saying, ‘no, no it’s OK, it’s just temporary retrograde amnesia, and it’ll just pass.’ ”

“He was trying to get you to lie down and be quiet and you kept saying, ‘no, no it’s OK, it’s just temporary retrograde amnesia, and it’ll just pass.’ ”

More laughter is heard in the room.

He did not know it then, but matters of memory consolidation would become a major aspect of his most eminent work. In collaboration with Dr. Lynn Nadel, Dr. Moscovitch challenged the standard model of memory consolidation. This model suggests that medial-temporal structures (located in the inner parts of the brain) like the hippocampus, are thought to only be temporarily involved in the management of autobiographical memories. Over time, it was thought that memories would be moved to the neocortex (in the outer areas of the brain), and then the hippocampal complex would no longer have a role in the storage or recovery of memories. This is true for semantic memories. These are memories concerning facts about ourselves and the world, such as where we were born and what school we attended, or knowing that Paris is the capital of France. Conversely, Dr. Moscovitch’s and Dr. Nadel’s multiple trace theory (MTT) suggests that it is not true about episodic memories, which are detailed memories of past experiences, such as your first romantic kiss. Retaining and recovering these memories always requires the hippocampal complex. They proposed that the hippocampus and the neocortex interact over time, creating multiple traces of activation in these brain areas. Repeated activation between these two brain areas ensures that an episodic memory will not be forgotten. As memories age, the more frequently they are evoked, the stronger they become. In contrast, memories that are not recalled, do not profit from this strengthening of traces, and are forgotten (4).

In practice, this theory has implications for conditions such as dementia and amnesia. If the hippocampus is responsible for the management of memory traces and the contextual details that surround it, atrophy or injury to this brain area means that an individual would suffer impairments in a whole host of activities. For instance, their language abilities might change because they can’t remember what they said as a conversation progresses. Or, they may lack the imaginative abilities to complete future oriented problem-solving tasks. Dr. Moscovitch explained that memory may even affect food intake. We rely on the memory of our last few meals to make decisions about our future meals. Since a person with a hippocampal lesion may not be able to remember what they ate, they may over or under eat. Although the impacts of atrophy or injury to the hippocampus have greater functional consequences than once thought, Dr. Moscovitch adds that the preserved abilities can be used to make up for the ones that are impaired.

The MTT as well as many of the other brain studies undertaken by Dr. Moscovitch have implications for rehabilitation care and practice. Knowing that the hippocampus may be able to retain specific kinds of memory, rehabilitation can work towards using spared functions in order to support what has been lost. Dr. Moscovitch cites research in Dr. Eva Svoboda’s laboratory at Baycrest, in which procedural memory is recruited to functionally aid other cognitive losses. Memorylink, a rehabilitation program, teaches adults with brain injury how to use smartphone technology as a cognitive aid to daily living. Capitalizing on the spared procedural memory functions, participants are taught a set of rules and procedures so that they can use a smartphone. The same step-by-step routine is practiced at each session, until the steps are internalized. Although the participants may not be able to verbalize the steps or have memory of the sessions, they are still capable of using the smartphone in their daily lives. The device can then be used as a memory aid – for scheduling, prompting of routines, and to take photos to review later (5). Dr. Moscovitch described how the Memorylink program was able to significantly improve the life of a man with topographic agnosia. Individuals with topographic agnosia are unable to navigate the environment. Even steps from his home, he could become lost. By learning to use the GPS on his smartphone, this man is no longer afraid to leave his home or his neighborhood (6). In fact, he travels the world with his smartphone in his pocket.

Although Dr. Moscovitch has made monumental contributions to neuroscience, his curiosity for the next research question continues. So, Dr. Moscovitch leaves us with an idea he would like to test out: he and his graduate student Jessica Robin have shown that episodic memory depends greatly on the environment in which they were formed (7). He explains that this has implications for aging in place for older adults with dementia. “If you’re familiar with the Robarts library as opposed to the AGO, the events that happened at Robarts will be described with much more detail than events happening at the AGO,” says Dr. Moscovitch. So it is possible that when you take a person out of their habitual environment, as commonly occurs for older adults with dementia who are relocated to long term care, you are also limiting access to memories which the environment allows them to have. This in turn may exacerbate their memory problems. This may be the next hypothesis Dr. Moscovitch tests — one that has direct implications for rehabilitation practice.

“She reminded me that this is our fiftieth Valentine’s Day together.”

Listening to Dr. Moscovitch talk about memory provides some food for thought. Having good memory is often considered a prized skill. A person with good memory is seen as a reliable worker, a good friend, and a trustworthy partner. Memories give us the sense of who we are and where we belong. Our interview lasted about an hour before Dr. Moscovitch said he had another important meeting to attend. It was Valentine’s Day and he had to meet with his wife for lunch. “She reminded me that this is our fiftieth Valentine’s Day together.” We are sure he would have remembered anyway. Dr. Moscovitch has excellent memory. And he has excellent memories.


 

References

  1. Hebb, DO. The organization of behavior. New York: Wiley & Sons; 1949.
  2. Olds J, Milner P. Positive reinforcement produced by electrical stimulation of the septal area and other regions of rat brain. J Comp Physiol Psychol. 1954;47:419–27.
  3. Bonner, J. Pioneering memory researcher Brenda Milner to receive Pearl Meister Greengard prize [internet]. Brighton: Medical News Today Healthline Media. May 26, 2011. [May 9, 2017]. Available from http://www.medicalnewstoday.com/releases/226617.php
  4. Nadel L, Moscovitch M. Memory consolidation, retrograde amnesia and the hippocampal complex. Curr Opin Neurobiol. 1997;7(2):217-27.
  5. Svoboda EV, Richards B. Compensating for anterograde amnesia: A new training method that capitalizes on emerging smartphone technologies. J Int Neuropsychol Soc. 2009;15(4):629-38.
  6. Rivest J, Svoboda E, McCarthy J, Moscovitch M. A case study of topographical disorientation: behavioural intervention for achieving independent navigation. Neuropsychol Rehabil. 2016;1-21.
  7. Robin J, Wynn J, Moscovitch M. The spatial scaffold: The effects of spatial context on memory for events. J Exp Psychol Learn Mem Cogn. 2016;42(2):308.