Researchers at the Howard Hughes Medical Institute’s (HHMI) Janelia Research Campus and collaborators at University College London (UCL) have proposed a new theory that sheds light on the process of systems consolidation in the brain. According to this theory, the usefulness of memory for future situations determines its storage location in the brain, challenging the classical view of systems consolidation. The study was published in Nature Neuroscience.
Systems consolidation involves the transfer of certain memories from the hippocampus, where they are initially stored, to the neocortex, where they reside long-term. Traditionally, it was believed that all memories eventually moved from the hippocampus to the neocortex over time. However, recent research has shown that some memories remain permanently stored in the hippocampus and are never transferred to the neocortex.
Psychologists have put forth various theories to explain this more complex view of systems consolidation, but none have mathematically determined what exactly determines whether a memory remains in the hippocampus or is consolidated in the neocortex. In this study, Janelia researchers propose a new, quantitative view of systems consolidation, introducing a mathematical neural network theory.
According to this theory, memories are consolidated into the neocortex only if they contribute to generalization. Generalizations are constructed from reliable and predictable components of memories, allowing individuals to apply them to different situations.
For instance, one can generalize the fact that canyons often indicate the presence of water. On the other hand, episodic memories are detailed recollections of specific past events with unique features. An example of episodic memory would be an individual’s recollection of hiking to a particular canyon and discovering a body of water.
Under the proposed view, consolidation does not involve the mere copying of memories from one brain area to another. Instead, it creates a new memory that generalizes previous memories. The extent to which memory can be generalized, rather than its age, determines whether it is consolidated or remains in the hippocampus.
To demonstrate the validity of their theory, the researchers utilized neural networks to investigate how the degree of consolidation varies based on the generalizability of a memory. Their experiments successfully replicated previous patterns that could not be explained by the classical view of systems consolidation.
The researchers now aim to test their theory through experiments to determine if it can accurately predict the degree of consolidation for a given memory. Additionally, they plan to investigate how the brain distinguishes between predictable and unpredictable components of memories to regulate consolidation.
Understanding the mechanisms of memory consolidation can significantly contribute to our knowledge of cognition, benefiting fields such as human health and artificial intelligence. Further exploration of memory processes can lead to advancements in addressing memory-related conditions and enhancing cognitive capabilities. By unraveling the complexities of memory storage and transfer, researchers can gain valuable insights into the fundamental workings of the human brain.
