Homeostasis of columnar synchronization during cortical map formation

ABSTRACTSynchronous spontaneous activity is critical for circuit development. A key open question is to what degree is this synchronization models adult activity or is specifically tuned for circuit development. To address this we used multi-electrode array recordings of spontaneous activity in non-anesthetized neonatal mice to quantify firing rates, synchronization, binary spike-vectors and population-coupling of single-units throughout the period of map formation. Consistent with the first hypothesis, adult-like network interactions are established during the period of retinal waves, before the onset of vision and normal inhibition, and are largely conserved throughout juvenile ages. Significant differences from mature properties were limited to initial topographic map formation, when synchronization was lower than expected by chance, suggesting active decoupling in early networks. These findings suggest that developmental activity models adult synchronization, and that there is remarkable homeostasis of network properties throughout development, despite massive changes in the drive and circuit basis of cortical activity.