Figure 1.

Spontaneous up and down states were recorded from organotypic slices cultured between 14 and 40 DIV. A, Example of a simultaneous extracellular population and dual intracellular recording of cortical neurons exhibiting synchronized activity during up state activity. B, Expanded time base. The amplitudes of intracellularly recorded up states were characterized by the maximum depolarization (peak amplitude) and mean depolarization (mean amplitude) from the down state baseline membrane potential in traces that had been stripped of action potentials by low-pass filtering (D; see Materials and Methods). C, The structural anatomy of organotypic slices showed typical laminar architecture of the cortex (note the Tbr1 staining of the deep layer) (Hevner et al., 2001). C1, The biocytin staining of a recorded layer 5 pyramidal cell.