How is information stored in the brain? This research project uses cutting edge technologies to mechanistically describe the construction of a memory. The ultimate goal is to reveal how information is encoded in the brain of an individual.
Memory is crucial to everyday life and allows us to adapt to our changing environment. Diseases of memory range from disorders of transience, e.g. Alzheimer’s disease, to disorders of persistence, e.g. post-traumatic stress disorder. As we know so little about memory function in health, it is essential that we achieve a fundamental knowledge of memory in order to understand and treat disorders of memory such as Alzheimer’s disease, drug addiction, and general cognitive decline in the ageing population. More fundamentally, to explain how brain leads to mind, we need to understand how information is coded in the brain. Memory provides a window into tracking the substrate of information, because when we learn something our brains necessarily change to assimilate information and store a memory. Understanding the nature of the particular change or plasticity that represents a memory is a crucial first step to investigating how it is coded.
The physical site of a specific memory in the brain, the memory engram, was originally hypothesized to be encoded in the learning-induced persistent changes of specific brain cells that retain information and are subsequently reactivated during remembering. Until recently neuroscience has investigated memory engrams indirectly. Traditional experimental approaches have focused on investigating the role of brain regions, circuits, and molecules in the capacity of memory formation in general. In contrast, comparatively few studies have investigated how specific memory engrams are stored in the brain. Engram cell-labeling technology has revolutionized the way memory can be studied, allowing us to test long-standing but unproven theories of memory storage. Using the promoters of immediate-early genes, sparse populations of neurons that are active during the time window of a learning episode can be labelled, observed, and manipulated. It has been established that sub-populations of neurons active during a defined training window are both sufficient and necessary for retrieval of targeted memories, and therefore are involved in the storage of specific memories in the brain. However, we do not currently know how they are contributing to storing specific information. This project will address how specific memories are stored in the brain as collections of memory engram cells. The mechanism for the induction of memory engram labeling will be investigated. The biological mechanism of memory formation (learning) will also be probed, in order to delineate how and why a specific subpopulation of brain cells are assigned to a given memory engram. Lastly, the mechanisms of memory updating will be investigated by studying how memory engrams can be linked.
