Figure 1
From: Light-evoked hyperpolarization and silencing of neurons by conjugated polymers
Sustained illumination of primary hippocampal neurons grown on P3HT silences evoked firing.
(a) A train of action potentials is induced by current injection (20 pA for 1 s; black line) in a representative neuron cultured over glass:P3HT (upper panel). In the same neuron (middle panel), the evoked activity was fully silenced by illumination of the conjugated polymer (500 ms, 16 mW/mm2; green bar). Light did not affect the firing activity evoked by current injection in neurons cultured over bare glass (lower panel). Traces are overlays of 10 consecutive sweeps. Blue boxes indicate the time windows used for quantification of the activity before and during the light stimulus. (b,c) Individual (black symbols) and mean (red symbols) firing rates measured in neurons grown onto glass:P3HT ((b); ***p < 0.001, paired t-test) or bare glass ((c); p = 0.0531, paired t-test) before and during the light pulse. (d) Mean (±sem) percent firing changes during illumination (negative values for reduction) with respect to the basal firing obtained in the two experimental groups (glass:P3HT, −65.79 ± 10.89%, n = 14; glass, −2.10 ± 8.38%, n = 19; ****p < 0.0001, t-test). (e) Mean values (±sem) of the resting membrane potential in neurons grown under the two experimental conditions (glass:P3HT, −54.39 ± 1.35 mV; glass, −52.12 ± 1.02 mV; p = 0.1745, Kolmogorov-Smirnov test).
