Figure 7.
Optogenetic activation of Pv interneurons distant from the focus blocks ictal event propagation and shortens ictal event duration at the focus. A, Schematic of the experiment. B, Representative voltage-clamp recordings (Vh = −50 mV) from a pyramidal neuron located >1 mm from the focus and simultaneous local field potential recordings at the focus in the absence (left and right) and in the presence (middle) of light stimulation starting 60 s before the double NMDA pulse. Calibration: 40 s, 0.01 mV, 500 pA. C, Percentage of propagating ictal events in the absence (n = 14, 3 mice) and in the presence of light stimulation (n = 8, 3 mice). D, Paired distribution of ictal event duration evoked by double NMDA pulses in the absence (empty and full black circles, n = 8, 3 mice) and in the presence (empty and full cyan circles, n = 8, 3 mice) of light stimulation, as measured from local field potentials recorded at the focus. The duration of the two ictal events that were not blocked by local optogenetic activation of Pv interneurons was not reduced. Mean values of black and cyan full circles are represented by full squares. Paired sample t test was performed on the values obtained from the six successful experiments (3 mice). **p < 0.01.