Visuosocial Preference Memory, but Not Avoidance Memory, Requires PLCγ1 in the CA2 Hippocampus

Area of Science:

• Neuroscience
• Animal Behavior
• Cognitive Science

Background:

• Visuosocial memory, the recall of visual information with social context, is well-established in primates.
• The presence and mechanisms of visuosocial memory in rodents, specifically mice, remain largely unexplored.
• The CA2 region of the hippocampus is implicated in social memory processing.

Purpose of the Study:

• To investigate the existence of visuosocial memory in mice.
• To identify the molecular mechanisms underlying visuosocial memory formation in the CA2 hippocampus.
• To determine the role of phospholipase C gamma 1 (PLCγ1) in visuosocial memory.

Main Methods:

• Development of a novel vision-specific social memory test using portraits and self-images.
• Genetic manipulation to delete phospholipase C gamma 1 (PLCγ1) specifically in the CA2 hippocampus.
• Assessment of social behavior and memory using the three-chamber test and a five-trial social memory test.

Main Results:

• Mice demonstrated the ability to distinguish conspecifics from other species, indicating visuosocial memory formation.
• Mice with CA2-specific PLCγ1 deletion exhibited impaired social memory but retained normal sociability.
• The impairment was specific to visuosocial preference memory, with non-social object recognition remaining intact.

Conclusions:

• Mice possess visuosocial memory, analogous to primates and humans.
• The BDNF-PLCγ1 signaling pathway in the CA2 hippocampus is critical for visuosocial preference memory in mice.
• This research provides novel insights into the neural basis of social recognition in rodents.