Members of the Perception Society had the privilege of attending a lecture by Old Carthusian, Dr Amy Milton (Director of Studies, Natural Sciences, Ferreras-Willetts Fellow in Neuroscience, Downing College, University of Cambridge) on the controversial but mesmerizing topic of erasing memories. Review by Anastasia Kolomiets (Year 12):
Dr Milton’s primary research is on Memory Reconsolidation, the process by which memories, becoming “active” after their retrieval, restabilize into the long-term memory. This is a highly experimental area of Behavioural Neurology; if it proves successful at "wiping memories to clean the slate”, Dr Milton and her fellow researchers can help treat drug addiction and issues associated with post-traumatic stress, including phobias
The talk focused on explaining how memory works and how scientists can influence it. Essentially, the long-term memory can be divided into Explicit (conscious recollection of previous experiences and information) and Implicit (unconscious process when previous experiences aid the performance of a given task). These, in turn, can be subdivided into Episodic (memory of autobiographical events that can be explicitly stated), Semantic (memory of facts), Procedural (motor skills, such as walking, cycling, talking) and Conditioning (memory where it has learnt that a given stimulus predicts an event that will occur; also, Pavlovian Conditioning) respectively. The latter, Conditioning memory, is the area Dr Milton focuses her research on.
However, here the story is far from over. Some fifty years ago, neurologists believed that long-term memory was inalterable (Consolidation Theory); every informational input finds its place in the brain somewhere and is there to stay. However, a revised vision of long-term memory, pioneered in the 2000s, is now backed up with more and more convincing evidence – Reconsolidation Theory. This theory claims that memory is “updatable”. The theory states that during the first 4-6 hours after an informational input, the memory is active and consolidates into the long-term memory. The memory can be made active again by retrieval. While it is active, it is unstable, and can be erased using amnesia drugs. That is how erasing memory works in a nutshell.
To illustrate these processes, Dr Milton told her audience about the results of the experiments she conducted into a rat's memory. But why rats? Surely humans are much more intelligent, complex creatures? Surely you cannot compare human brains to those of rats? In fact, even though humans ARE intelligently superior to rats, our brains are not as different as one might think. A rat's limbic system, neurochemistry and psychological process, is similar to those of a human, which renders them perfect for this type of research.
The experiments were based on principles of Pavlovian conditioning and the use of Propranolol, a drug which influences adrenalin receptors in the brain, triggering amnesia. The experiments conducted were to investigate drug addiction and post-traumatic stress; the principles of experiments concerning these two areas were essentially the same - a lesson, a stimulus, a drug. The experiments investigating post-traumatic stress taught rats to be afraid of the sound of a bell as they associated it with a mild unpleasant electric shock. This conditional memory was allowed to stabilize in the long-term memory, mimicking the way an accident stays in the victim’s memory after it has happened. Then the memory was made active again by repeating the stimulus (bell) without the subsequent unpleasant event (electric shock), and propranolol was injected to half of the rats. This was repeated, and the results showed that the rats who had received propranolol injections feared the bell much less, while those which did not get the drug feared the bell on the same high level. Could this be a scientific breakthrough?
The potential application of this finding is staggering but there is more research to be done into this area before the technique could be extended to treat humans.
The lecture was nothing short of fantastic and questions included discussions of difficulties associated with selective amnesia and the differences in brain structure.