Figure 11.

The emergence of the unidirectional circuit organization in the developing hippocampus occurs at about the end of the second postnatal week. A,B: Time series data of imaging photostimulation-evoked network activity by glutamate uncaging in DG and distal CA3 in a P7 slice, respectively. The uncaging site is denoted by a purple star. C,D: Time series data of imaging photostimulation-evoked network activity by glutamate uncaging in DG and distal CA3 in a P14 slice, respectively. Note that photostimulation and imaging of both slices were performed through a 2× objective and that three trials of imaging data were averaged for the presentation. Given the lower sensitivity of the 2× objective, the weaker activated granule cell layer of DG does not show as well as hilar activation in the frames presented in B, but it is detected with our signal analysis.