Fig. 3.

GABA acting at GABA_A receptors generates collective axonal behavior in a gap junction and action potential-dependent manner in stratum oriens minisections. (a) Stratum oriens minisections were bathed in aCSF containing 50 μM D-AP5 and 20 μM SYM 2206. This solution, containing in addition 0.5 mM GABA, was transiently perfused into the bath as illustrated (black bar). GABA generated a transient period of enhanced high-frequency activity as illustrated in the spectrogram. (b) Preperfusion of the stratum oriens minislices with 20 μM bicuculline abolished the effects of GABA perfusion. (c) Preperfusion with 0.2 mM carbenoxolone significantly reduced the GABA-induced collective axonal behavior. Time axes for the traces are the same as the spectrograms. (Scale bars, 50 μV.) (d) Expanded time axis recordings of the data illustrated in a–c (asterisks). Tetrodotoxin blocked all spontaneous activity and that induced by GABA. (Scale bars, 50 μV and 100 ms.)