Figure 4.
Weak electrical stimuli in CA3 activate specific patterns in CA1. A, Activation of distinct neuronal subpopulations in CA3 activates different upstream neuronal cells resulting in different SPW-R waveforms. B, Comparison between spontaneous and evoked SPW-Rs reveals no difference in waveform and frequency components (for details, see supplemental Fig. S9, available at www.jneurosci.org as supplemental material). C, Weak activation of CA3 cells at 300 ms after a strong stimulation. Evoked SPW-Rs are confined to few, strongly connected areas within the SOM (left panel) created of spontaneous and evoked events. Furthermore, evoked SPW-Rs show clearly distinct, but reproducible stable waveforms at two different stimulation locations (middle). On a SPW-R hit map generated from spontaneous events (right panel), these elicited SPW-R events are homogenously distributed. D, The variance of evoked SPW-R events is significantly smaller than the variance of all SPW-Rs, indicating a specific interaction between stimulated cells in CA3 and resulting activated cells in CA1; *p < 0.05.