transmission) was induced by eliciting 100 pulses at a frequency of 1 Hz (LFS1; low-frequency stimulation) at twice the stimulation intensity as the test pulse. Access resistance (Ra) was monitored online and cells showing changes in Ra of >20% or an Ra >20 mΩ upon break-in were excluded from the analysis. To determine the paired pulse ratio (PPR), paired stimulations were delivered at an interval of 100 ms. PPR was calculated as the peak amplitude of the second stimulation divided by the peak amplitude of the first stimulation. The percent increase in PPR between baseline and 35–40 min post-LFS were compared by paired t-test.
