Figure 3

(a) MEA positioned into the recording system (MEA1060; Multichannel Systems, Reutlingen, Germany) with an acute hippocampal brain slice positioned at the center of the circular chamber. A mesh is placed on top of the slice to prevent any movement and facilitate the penetration of the three-dimensional electrodes into the slice. aCSF saturated with carbogen at a temperature of 33.0 °C was perfused inside the chamber (right tube) and siphoned at the bath level interface. (b) Picture taken with an optical microscope of an acute hippocampal brain slice positioned on an array of electrodes. Areas such as the mid-brain (MD), thalamus (TH) and hippocampus (H) are clearly visible. (c) Example of bursting neural field potential recorded with the three-dimensional gold microelectrodes (high 8.5 mM K⁺). Various patterns of activity were recorded, including ictal like events typically seen during seizure-like events. (d) Activity recorded simultaneously within the thalamus and mid-brain from the same brain slice. Notice moving ictal timeframes indicative of seizure propagation (b). (e) Simultaneously, activity was recorded within the hippocampus (CA1 (H3/H4/H5), CA2 (H2) and CA3 (H1)).