Memory

Date: October 21st

Location: Your couch! See your e-mail for the Zoom link!

Directions: See your e-mail for tips for signing into Zoom!

Credits: Today’s reading is adapted from lessons written by the incomparable Mary Burns for SDCE.

What is memory? Where are memories stored in our brains? We talk each week about the amazing power of our brains and memory might be one of the most impressive of all. Our memories are based on sensory experiences and input, which the brain collects, connects, and creates a summary of. Our brains are essentially made of memories.

Neuroscientists describe memory as a reactivation of connections between different parts of our brains that were active at some point. All animals have at least some ability to learn from the past, likely so they can protect themselves from danger. A single neuron connects to thousands of other neurons, and these connections can be adjusted with stronger, or weaker, signals. Every experience that our brain inputs has the potential to reroute and strengthen these neural pathways. But memories aren’t stored in a specific place in our brains or a certain set of neurons; our brains are the entire system of memory storage.

Parent faces are photons on the retina, which sends a message to the visual cortex. Infants hear a parent voice and the auditory cortex transforms the sound waves into electrical signals. Hormones are released when a parent makes the infant feel good and safe. Researchers believe that the neurons, molecules, and synapses all encode these sensory events in terms of a relative time window from when they happen and pack them in the brain together. Researchers see this as a nested system, with memories existing in multiple time windows. As brain researchers have embarked on a remarkable journey to map the human brain, called the Human Connectome Project they are learning more about how this impressive system works to create and store memories.

This week in class we will be exploring how memories are created and testing different strategies for improving our memory processes. But first, let’s explore just how well they work?

Quick what were you doing when President Kennedy was assassinated? What were you doing when you heard about the planes on 9/11? Most people can recall, often in great detail, what they were doing when life-altering events occurred. But do you remember the color of the car that drove past your house last? The name of the street you lived on 30 years ago? Some memories seem to ‘stick’ better than others and researchers are still working on figuring out why.

Some researchers believe that each time we recall a memory, it alters it in some way. Neuroscientist Karim Nader believes that some memories are more susceptible to change upon recall than others, especially big memories like assassinations. This is thought to occur because we tend to replay the over and over, discussing them with friends, thinking about them again and again, and each repetition leaves the potential for us to alter them in the retelling (like a brain game of ‘Telephone’). Of course, not all neuroscientists agree with this theory. But if memory change is, in fact, possible, it could be good news for those with traumatic memories or experiences with post-traumatic stress disorder.

What scientists do agree on is that recording a memory requires that the connections between neurons adjust. Each memory changes some area of the neurons in the brain and builds messages from proteins. Nobel Prize winner and neuroscientist Eric Kandel studies memory on the microscopic scale and has shown that short-term memories involve quick and simple chemical changes that make the synapse fire more efficiently. He has also discovered that to build a memory, neurons must manufacture new proteins to help the neurotransmitter move more efficiently. Our brains are always working to achieve efficiency and memories are no exception! Dr. Kandel, unlike Dr. Nader, believes that once a memory has been constructed and ‘consolidated’ in the brain, it is stable and cannot be undone.

Recall those stand out ‘flashbulb’ memories, like assassinations or world shaking events. People tend to have relatively accurate recollection for the basic facts of the event (people remember that four planes were hijacked on 9/11 and that JFK was with his wife in Dallas). But people often misremember what they were doing and where exactly they were. Researchers think this may be due to two different types of memories that are being reactivated at different times; central facts and experience. Televisions and media reinforce the central facts, but your memory of the location may be affected by your current environment.

Other studies indicate that fearful memories can be altered with drug treatment. Doctors at the Douglas Mental Health University Institute have been studying people with post-traumatic stress disorder, giving some participants a drug (propranolol) and others a placebo. Propranolol is typically used to treat high blood pressure and is used to combat stage fright in performers, but one of the side effects is memory loss. Patients were studied as they recounted a traumatic memory, and while there was no immediate difference between those with the drug and those with the placebo, researchers began noticing differences after the first week. Those who had taken the drug were now calmer when they recounted the traumatic memory. Ultimately, those who took propranolol once a week for six weeks showed an average of 50% reduction in symptoms of their PTSD, including fewer nightmares and flashbacks, even after the drug wore off. The drug didn’t erase the memories, but it did seem to change the quality of it, so that the emotional tone of the trauma became weaker each week.

So, is it a big deal if we misremember? If our memories didn’t happen quite the way we think they did? For the most part, no. If you remember ironing when you heard about JFK (my grandmother remembers ironing when the news bulletin came on the TV), but you were in fact folding laundry, no one is harmed if your memory is slightly altered. But sometimes faulty memories, or even implanted memories, can have real world consequences. Consider the following case:

In 1988, Paul Ingram, a police officer, was arrested for sexually abusing his two daughters, something he vehemently denied. Over a period of five months, amid pressure by fellow police officers, psychologists and other advisors who suggested that he had committed child abuse, he eventually began to confess. Not just to abusing his daughters, but other types of rapes, child abuse and even participation in a Satan-worshipping cult where he allegedly murdered 25 babies.

At one point, the prosecution brought in a memory researcher, Dr. Richard Ofshe, who was suspicious of his credibility. To test him, he made up a story that his son and daughter claimed he had forced them to have sex with each other while he watched. (This was something that had NOT actually happened.)

Over a period of several hours, despite initially denying the memory, he slowly began to generate these false memories. Ultimately, he wrote a three-page confession to a crime which was completely made up.

Unfortunately, the report wasn’t issued until after he had confessed to the crimes and had been convicted. He was then unable to withdraw his guilty plea. He remained in jail until 2003 and is still a registered sex offender.

For those who visited the San Diego Innocence Project, you might remember how fraught a police line up can be, and how cues and subtle hints can alter a victim’s memory. For more on this issues, read this article here:

Mistaken eyewitness identifications make up approximately 69% of the more than 375 wrongful convictions that have been overturned with post-conviction DNA evidence, according to the Innocence Project. 34% of those involved in-person lineups. To see more stats on exonerees, check out the Innocence Project information here:

Cohen, J. (2017, January). Memory Implants. Retrieved from www.technologyreview.com: https://www.technologyreview.com/s/513681/memory-implants/

Hogenboom, M. (2013, September 29). Why does the human brain create false memories. Retrieved from bbc.com: http://www.bbc.com/news/science-environment-24286258

Human Memory: Parts of the brain. (2010, August). Retrieved from human-memory.net: http://www.human-memory.net/brain_parts.html

Implanting False Memories: Lost in the Mall & Paul Ingram. (2008, February). Retrieved from spring.org.uk: http://www.spring.org.uk/2008/02/implanting-false-memories-lost-in-mall.php

Miller, G. (2010, May 1). How Our Brains Make Memories. Retrieved from www.smithsonianmag.com: https://www.smithsonianmag.com/science-nature/how-our-brains-make-memories-14466850/

Stockton, N. (2017, July 19). Your brain doesn't contain memories. It is memories. . Retrieved from www.wired.com: https://www.wired.com/story/your-brain-is-memories/