Involvement of Thalamus in Initiation of Epileptic Seizures Induced by Pilocarpine in Mice
Figure 1
Multichannel microelectrode recordings. Two bundles of electrodes were inserted into the CA1 region of the left hippocampus and PF region of the left thalamus, respectively. Each bundle consists of two tetrodes and each tetrode is formed of four insulated nickel-chrome alloy electrodes (diameter of 13 μm, impedance of 0.5–1.0 MΩ). For each electrode, we extracted single-unit activities and LFPs. Single-unit activities were obtained by filtering the recording at 300–6000 Hz and sorting the filtered data using OfflineSorter software (Plexon Co, USA). To obtain the LFPs, we filtered the data at 0.5–100 Hz. (a) Multichannel microelectrode. The enlarged view shows one bundle of electrodes consisted of two tetrodes and the cross-section through a tetrode. (b) LFPs from a tetrode in the normal hippocampus. (c) Multiunit activity (MUA) of the same tetrode. (d) Example of single-unit activity. The upper trace is the spike train sorted from the MUA in (c). The spikes were from four neurons denoted by four colors. The left bottom traces show the superimposed single waveforms of spikes of four neurons. The right bottom figure shows the four clusters in the feature space, which were projected by the spikes of the four neurons, by using the principal component analysis (PCA) method. H, hippocampus; T, thalamus; T1&T2, Tetrode 1 and Tetrode 2 in a bundle. For example, H-T1-2 means the second channel of Tetrode 1 in hippocampus.
