University of Texas Scientists Discovered Episodic Memory Neurons , in the hippocampus and entorhinal cortex of the human brain. The results, published in the journal NeuroImage, will help develop new treatments for mental disorders and traumatic brain injuries.
A study of the memory mechanism involved 27 epilepsy patients who had electrodes implanted during the surgical treatment of intractable epilepsy. Volunteers performed memorization tasks, which made it possible to determine the activity of the involved nerve cells. A total of 103 neurons were identified, the firing frequency of which was associated with the successful formation of episodic memory – memory of personal experience, including the memory of the place and time of events.
As the authors of the work write, these neurons have important properties. For example, they exhibit the same pattern of activity when a person memorizes information and when he tries to extract this information from memory. This activity may be related to schizophrenia, when, due to dysfunction of the hippocampus, patients often cannot distinguish delusions or hallucinations from real memories.
The results complement an important model of memory formation called “Phase separation during encoding and retrieval” ( Separate Phases at Encoding And Retrieval, SPEAR) and built on the basis of experiments on rodents. This model explains how the brain manages to distinguish between old and new memory when retrieving information. Scientists have shown that peak neuronal activity is tied to the hippocampal theta wave phase, but this phase shifted between memory encoding and recollection.