“…DLR is consistent with the experimental data of [Gambino et al, 2014, Stein et al, 2021] insofar as synaptic plasticity only occurs in the presence of an NMDA spike, i.e., y = 1. Furthermore, consistent with the results of [Stein et al, 2021], the decision between LTP and LTD depends on the presence of a signal that causes Ca 2+ -influx in temporal proximity, which can be caused in L2/3 pyramids by a backpropagating action potential, and in L5 pyramids by a Ca 2+ -spike that is triggered when significant depolarization in the apical tuft coincides with a somatic spike [Larkum, 2013, Larkum et al, 2022]. In addition, DLR predicts that the amplitude of LTP is scaled by the term q w ( x ) = σ ( β ( w · x – u 0 )), i.e., by the current excitability of the dendrite for NMDA spikes, reducing the amplitude of LTP if this excitability is already fairly high.…”