Measuring the amplitudes of paired-pulse iGluSnFR signal transients thus revealed a clear trend towards lower PPR, hence higher P r values, with greater distances from the s. pyramidale (PPR mean ± SEM: 1.49 ± 0.01, n = 33; regression at p<0.001; Figure 3C ).
Although their dataset did not reach statistical significance at n = 6, it clearly pointed to the trend reported by us.
A systematic application of this protocol at n = 67 individual synapses (53 cells) has revealed a highly significant trend towards higher P r at more distal synapses ( Figure 1C ), with average P r = 0.36 ± 0.02 (mean ± SEM).