A new study has found that while general memories of experiences are stored in the hippocampus, a brain structure long thought to be the storehouse of memory, individual details are analyzed and stored elsewhere.
After an unforgettable dinner in a restaurant, not only the food impresses you, but also the smells, decor, sounds of music, conversations and many other features that combine to create an unforgettable experience. Subsequently, the mere revival of any of these impressions may be enough to recreate the entire experience.
The study showed that the complex memory of the brain also consists of a whole and its parts. The researchers found that while the overall experience is stored in the hippocampus, individual details are parsed and stored in the prefrontal cortex.
This separation ensures that in the future, exposure to any single signal will be enough to activate the prefrontal cortex, which then reaches the hippocampus to restore all memory.
The results, published in the journal Nature, shed light on the distributed nature of memory processing in the brain and provide new insight into the memory retrieval process, which is less understood than memory storage.
It has been difficult to study memory as a distributed brain process, due in part to technical limitations. Priya Rajasthopathy, a neuroscientist at Rockefeller University, and her colleagues have developed new methods to record and process neural activity from multiple brain regions simultaneously as mice navigate through a multi-sensory experience, encountering sights, sounds, and smells in an endless corridor of virtual reality. .
The researchers trained mice to associate different rooms, made up of different sets of sensory cues, as rewarding or unpleasant experiences.
Later, under the influence of a specific smell or sound, the rats were able to recall a broader experience and knew what to expect: sugar water (beneficial experience) or an unpleasant puff of air (unpleasant experience).
Experiments have shown that while the intrinsic hippocampal pathway, a well-studied circuit involving the hippocampus and its environs, was required for the formation and storage of experience, separate sensory functions are transferred to prefrontal neurons. Later, when the mice experienced certain sensory traits, another circuit kicked in.
This time, the prefrontal neurons communicated with the hippocampus to trigger the corresponding complete memory.
“This indicates that there is a specific pathway for memory retrieval, separate from memory formation,” says Nakul Yadav, the study’s first author and graduate student.
These findings have implications for the treatment of conditions such as Alzheimer’s disease, where deficits are thought to be more related to memory retrieval than storage.
The existence of separate storage and retrieval pathways in the brain suggests that targeting frontal lobe memory pathways may be more therapeutic.
Source: Medical Express