a. Representative z-scored images of early spontaneous
activity at P23, seven days prior to EO. b-c. Early spontaneous
activity shows hallmarks of mature spontaneous activity, including long-range
correlated activity (Pearson’s correlation) (b) and
pronounced spontaneous fractures (c). d. The spatial
scale of correlations in spontaneous activity (decay constant fit to correlation
maxima as function of distance from seed point) is already large early on and
changes little across ages. Data points were grouped into four age bins. P
denotes postnatal age relative to EO. e. The magnitude of
long-range correlations for maxima 2 mm from the seed point is statistically
significant at all ages examined (p<0.0001 vs. surrogate data). For d, e:
n=10 chronically recorded animals; e: asterisks indicate p<0.0001, actual
vs surrogate data; d,e: group data is shown as mean ± SEM.