Social play behavior shapes the development of prefrontal inhibition in a region-specific manner

Abstract

Experience-dependent organization of neuronal connectivity is critical for brain development. We recently demonstrated the importance of social play behavior for the developmental fine-tuning of inhibitory synapses in the medial prefrontal cortex (mPFC) in rats. When these effects of play experience exactly occur and if this happens uniformly throughout the prefrontal cortex is currently unclear. Here we report important temporal and regional heterogeneity in the impact of social play on the development of excitatory and inhibitory neurotransmission in the mPFC and the orbitofrontal cortex (OFC). We recorded in layer 5 pyramidal neurons from juvenile (postnatal day (P)21), adolescent (P42) and adult (P85) rats after social play deprivation (SPD; between P21-P42). The development of these PFC subregions followed different trajectories. On P21, inhibitory and excitatory synaptic input was multiple times higher in the OFC than in the mPFC. SPD did not affect excitatory currents, but reduced inhibitory transmission in both mPFC and OFC. Intriguingly, the reduction occurred in the mPFC during SPD, while the reduction in the OFC only became manifested after SPD. These data reveal a complex interaction between social play experience and the specific developmental trajectories of prefrontal subregions.