In the 1970s, researchers John O’Keefe and Jonathan Dostrovsky discovered that certain cells in the hippocampus of rats were activated when the rats were in specific locations in their environment. These cells were dubbed “place cells” and are now known to play a critical role in spatial memory. The firing patterns of place cells are highly specific to the location of the animal, suggesting that they are involved in spatial representation. While the exact mechanisms of memory storage are still being explored, it is clear that the hippocampus plays a critical role in the formation and retrieval of memories, including spatial memory.
Various theories about the specific mechanisms of memory storage have been proposed over the years. One well-known theory is that memories are stored in the brain through changes in the strength of synaptic connections between neurons, a process known as synaptic plasticity. This theory is supported by studies showing that long-term potentiation, a process that enhances the strength of synaptic connections, is associated with learning and memory.
Researchers from Northwestern University in collaboration with the University of Chicago Epilepsy Center, have discovered how memory is stored inside the brain during sleep. The team implanted electrode probes inside five patients’ brains to measure electrical activity in response to sounds administered by the research team during a learning exercise. Half of the sounds were associated with objects and their precise spatial locations that patients learned before sleep.
The study found that sound associated with previously learned stimuli reactivated memory and improved memory storage. The new data from the implanted brain electrodes showed that object sounds presented during sleep elicited increased oscillatory activity, including increases in theta, sigma, and gamma electroencephalographic (EEG) bands. The presence of electrophysiological activity in the hippocampus and the adjacent medial temporal area of the cerebral cortex reflected the reactivation and strengthening of corresponding spatial memories.
Overall, the evidence suggests that the hippocampus is a critical brain region for spatial memory and that electrophysiological activity in this region is tightly linked to spatial navigation and representation.
Tags: brain, memory, neuroscience, science, sleepCategorised in: Uncategorized
This post was written by Evelyn Eekels