Fig. 6

Failure of population activity after exposure to high calcium-containing media. Two electrodes within an oblique section of claustrum, separated by 2.25 mm (450 μm interelectrode spacing) showed evoked population bursting that spreads from electrode 32 toward electrode 27. After addition of 8 mM calcium to the ACSF to lower the overall excitability of neurons, population spikes are smaller, less numerous, and the broadening of excitatory–excitatory connections [62] is more readily evident. The all or nothing quality of late population spikes by showing two sweeps superimposed