Traveling waves in developing cerebellar cortex mediated by asymmetrically connected Purkinje cells

(a) GABA-evoked currents recorded in a P6 Purkinje cell using gramicidin perforated-patch recordings (see Supplementary Methods). Example traces at different holding potentials are superimposed (top), with the respective peak GABA-evoked current amplitudes plotted below. Scale bar, 50 pA, 100 ms. (b) GABA-evoked currents recorded in a P36 Purkinje cell. Scale bar, 50 pA, 100 ms. (c) The GABA reversal potential (EGABA) is depolarizing in the first week, but shifts to hyperpolarized values during the second postnatal week. Examples in panels (a) and (b) are indicated with red and blue closed circles, respectively. (d) Most synaptic properties exhibit no age-dependence when comparing data from 1-week-old (P4 – P6) and 2-week-old (P7 – P14) animals. There were no significant differences for PSP amplitude (n = 7/7, P4 – 6/P7 – P14; P = 0.90), latency (n = 9/12; P = 0.89), or τdecay (n = 9/12; P = 0.63). However, there was significantly more paired-pulse depression in P4 – 6 animals (n = 18/6; P = 0.009). PSP amplitude was recorded with symmetrical Cl internal solution. Values are mean ± s.e.m. (e) Spontaneous firing rate is lower in young animals and increases during development. Firing rates were measured using cell-attached patch or extracellular recordings.