Synchronized LFP rhythmicity in the social brain reflects the context of social encounters

Abstract

Mammalian social behavior is highly context-sensitive. Yet, nothing is known about the mechanisms that modulate social behavior according to its context. Recent studies have revealed a network of mostly limbic brain regions, here termed the "social brain", which regulates social behavior. We hypothesized that coherent theta and gamma rhythms couple regions of the social brain into functional networks in a context-dependent manner. To test this concept, we simultaneously recorded extracellular activity from multiple social brain regions in mice performing three social discrimination tasks. Local field potential rhythmicity during a task was mainly sensitive to an internal arousal state. However, during stimulus investigation we observed a distinct state, which was sensitive to stimulus characteristics. Yet, the coherence between the various regions was most sensitive to the social context. Moreover, we found the ventral dentate gyrus to play a pivotal role in coordinating the context-specific rhythmic activity in the network.

Impaired emotion recognition inCntnap2-deficient mice is associated with hyper-synchronous prefrontal cortex neuronal activity

“…Moreover, we found a generally high level of theta coherence induced by social encounter in all tasks, suggesting that the various recorded brain regions are over-synchronized in KO mice during social behavior. Such generally high coherence among brain regions may cause behavioral abnormalities by masking social context-induced specific patterns of coherence between brain regions, which may be required for proper recognition of and appropriate responses to specific stimuli 37 . This result is in agreement with a recent study that used fMRI and cFos expression analyses to demonstrate macroscale functional hyper-connectivity in Cntnap2 -KO mice 38 .…”