- Published: November 10, 2012
Recent studies at MIT have found that memories in the brain now have biomarkers. It is possible that individual neurons contain specific memories. These portions of trances of memories are referred to as engrams. Engrams were not always thought to have biological components, but were rather used to indicate theoretical portions of memories. MIT's study incorporating the use of "optogenetics" has found that the activation of a small area of brain cells can allow a person to recall and entire episodic memory in full detail. This was originally an accidental observation by Canadian neurosurgeon Wilder Penfield who performed surgeries on epileptic patients to remove specific areas where the epilepsy would occur. In order to do this, Dr. Penfield stimulated certain parts of the brain will small jolts of electricity and recorded the patients' reactions. Sometimes, patients were able to recall full events in detail when areas of the hippocampus were stimulated.
With current technology, we can use optogenetic to stimulate neurons that are genetically modified to display light-activated proteins. The idea was that a memory could be reactivated without sensory stimulation (as it has been frequently shown that the Olfactory system is integrally linked to the Limbic system, allowing for a person to recall an entire childhood memory with the whiff of a familiar soup). By performing learning and memory experiments on mice, Dr. Liu asserts that, "Our results show that memories really do reside in very specific brain cells, and simply by reactivating these cells by physical means, such as light, an entire memory can be recalled" .
So what consequences does this have for a forward-looking legal system that integrates Neuroscience? To begin, if the origins of certain memories can be ascertained, then it might become possible to 'tamper' with a witness and 'erase' the memory so that what used to be an eyewitness testimony can be removed from a case. On a more theoretical note, if memories can be reactivated with specific brain cells, what measures would have to be taken before memories can be implanted so that false memories can throw off a case? There are many things to consider with such findings, but overall it is not an overbearing threat at this time. The research has only been conducted on mice and not yet proven in humans. Additionally, the type and strength of the memory has not played a significant role in this study. If there is a memory someone holds that is so strong it continues to come back with PTSD, what is the likelihood that this memory can be altered, deleted or physically revisited? And how would this work? These and other questions must be considered when trying to understand the impact of such a study on a forward-looking legal system. Even now, there would be much more refinement before this kind of research could be valid in a court of law.
Source: Researchers show that memories reside in specific brain cells. Cathryn Delude, Picower Institute for Learning and Memory, MIT