Recording at the apical dendrite during TBP-LTP in dorsal and ventral neurons. A, Schematic of the experimental configuration. Voltage responses were measured at the dendrite (120–150 μm). EPSPs were evoked using a stimulating electrode placed at the SC inputs. Antidromic stimulating electrode (blue) was used to elicit bAPs. B, Schematic showing the pairing of SC EPSPs with bAPs during TBP. C, Top, Example voltage traces recorded during five bursts of TBP trains in dorsal (black) and ventral (red) dendrites. Bottom, The last burst in the TBP train is expanded. Two-headed arrows indicate measurement of plateau potential duration. D, Summary graph showing the difference in time course of TBP-LTP between dorsal (n = 8) and ventral neurons (n = 7) (unpaired t test, t(13) = 4.65, p = 0.0004). Right, Traces represent example EPSPs recorded from dorsal and ventral dendrites during baseline and after TBP. E, Backpropagating spike amplitude at the dendritic recording location before LTP induction for dorsal and ventral neurons (unpaired t test, t(13) = 2.1, p = 0.055). F, Duration of plateau potentials during TBP trains recorded from dorsal and ventral dendrites (unpaired t test, t(13) = 2.1, p = 0.055). G, Initial RMP of dorsal and ventral dendrites (unpaired t test, t(13) = 8.5, p = 1.07e−06). E–G, Open circles represent individual cells. Closed circles represent mean ± SEM. *p < 0.05. **p < 0.01.