MALE SPECIFIC ABERRANT SPREAD OF NEURONAL AVALANCHES IN THE PREFRONTAL-AMYGDALA CIRCUIT FOLLOWING EARLY LIFE STRESS

Developing brain networks undergo intense reorganization vulnerable to adverse events such as early life stress (ELS). ELS has been linked to numerous cognitive and emotional deficits extending into adulthood. Here we investigated how ELS affects spread of neuronal avalanches in a rat model of maternal separation (MS) in prefrontal cortex (PFC) and basolateral amygdala (BLA), regions critical for emotional processing and particularly vulnerable to ELS.
Rat pups were separated from dams for 3 hours daily during postnatal days (p) 2 – p14. Local field potential (LFP) activity was recorded from PFC and BLA in urethane anesthetized young adult (p50 – p60) rats.
We showed that in both PFC and BLA negative deflections of LFP (nLFPs) formed spatial-temporal clusters, or neuronal avalanches. Most of the avalanches remained local within PFC or BLA and only around 5 % of avalanches spread across both regions. Interestingly, local clusters tended to have smaller size than clusters spanning both regions suggesting a filtering mechanism favouring spread of larger clusters between the regions. In the separated (MS) group, prefrontal nLFP clusters followed by BLA clusters had larger sizes and each nLFP from the PFC was followed by less nLFPs in the BLA compared to unseparated controls in males but not females. No MS related changes were found in the avalanches starting from the BLA.
Taken together our results suggest that MS leads to the male-specific impaired activity spread from the PFC to the BLA while spread of activity from the BLA to the PFC remains unaffected by MS.