Negative memories associated with social defeat are more likely to take hold and "stick" to a web of neurons in some brains than others, according to a new study (Zhang et al., 2019) in mice. This web of neurons is called an "engram."
In their recent study, "Negative Memory Engrams in the Hippocampus Enhance the Susceptibility to Chronic Social Defeat Stress," researchers from the Douglas Hospital Research Centre at McGill University tagged hippocampal engrams that formed after mice had experienced social stress and examined their subsequent behavior. These findings were published August 12 in the Journal of Neuroscience.
Although this study was conducted using a mouse model, senior author Tak Pan Wong and colleagues speculate that negative memories held in the hippocampus could underlie some of the cognitive symptoms associated with depression in humans. Wong is an associate professor in the Department of Psychiatry at McGill University.