Figure 4. Spatio-Temporal Dynamics of Astrocyte Ca²⁺ Activity.

(A) Definition of nearby (less than 50 μm) and distant (greater than 50 μm) cell pairs.

(B) Fluorescence changes in two nearby astrocytes.

(C) Cross-correlogram of fluorescent intensity.

(D) Mean cross-correlation of ΔF/F₀ in all nearby (thick line) and distant (thin line) cell pairs in control condition (left) and in the presence of bicuculline (right). Note large increase of ΔF/F₀ correlation in nearby cell pairs in the bicuculline condition (error bar: standard error of the mean).

(E) Relationship between distance of the two cells and the magnitude of correlation at zero timelag. Note lack of a reliable relationship in the control condition (left). Note also the significant negative correlation between the distance and correlated ΔF/F₀ changes in cell pairs in the bicuculline-treated cortex (right).