Researchers at Columbia’s Zuckerman Institute, led by Dr. Steven A. Siegelbaum, conducted a study to investigate how the brain distinguishes between threats and safety. They focused on the hippocampus, specifically the CA2 and CA1 regions, which play a role in social memory and memory for places, respectively. The study revealed that CA2 helps encode whether individuals are safe or risky, in addition to recognizing them. The researchers published their findings in Nature Neuroscience on October 15.
In the study, mice were given a choice to meet unknown mice in different locations and receive a mild foot shock, or avoid them altogether. The mice quickly learned to avoid locations and individuals associated with the shocks, demonstrating their ability to remember threatening experiences. By selectively suppressing the CA1 or CA2 regions in the hippocampus, the researchers found that silencing CA1 impaired location-based memory, while silencing CA2 caused indiscriminate fear towards strangers. This suggests that CA2 plays a crucial role in determining the safety of social encounters.
In addition to shedding light on the mechanisms behind social memory, the study has implications for neuropsychiatric conditions like schizophrenia and autism. The researchers suggest that further investigation into the CA2 region could provide insights into disorders related to fear of others, such as social anxiety and PTSD. Understanding how the brain distinguishes threat from safety could lead to more effective diagnostics and treatments for these conditions.
Dr. Siegelbaum believes that targeting CA2 could be a promising approach for diagnosing and treating disorders linked to fear of others. Social withdrawal symptoms, often seen in these disorders, may be related to an inability to differentiate between threatening and non-threatening individuals. By understanding the role of CA2 in social memory, researchers may be able to develop more targeted interventions to help individuals with these conditions.
The study, titled “The hippocampal CA2 region discriminates social threat from social safety,” was published online in Nature Neuroscience on October 15, 2024. The authors, led by Dr. Pegah Kassraian, reported no conflicts of interest. The research highlights the importance of social memory in avoiding harmful experiences and recognizing safe individuals, with implications for understanding and treating disorders associated with fear of others.
Overall, the study provides valuable insights into how the brain processes social memories and distinguishes between threats and safety. By uncovering the role of the CA2 region in encoding social threat, the researchers have opened up new possibilities for investigating neuropsychiatric conditions and developing targeted treatments. Understanding the mechanisms behind fear of others could lead to improved diagnostics and interventions for individuals struggling with social anxiety, PTSD, and related disorders.