What resolves this contention: Both studies attribute t-LTD at L2/3-L2/3 horizo…

What resolves this contention: Both studies attribute t-LTD at L2/3-L2/3 horizontal synapses to postsynaptic NMDARs, but disagree on subunit identity (GluN2B vs no claim) and the locus question for vertical L4-L2/3 (presynaptic NMDAR-dependent presynaptic expression vs postsynaptic GluN2C/D dependence) — implying overlapping but distinct molecular accounts of vertical-vs-horizontal t-LTD at the same postsynaptic cell. / Moreover, whereas t-LTD at vertical inputs requires presynaptic NMDA receptors and is expressed presynaptically, using paired recordings we find that t-LTD at horizontal inputs requires postsynaptic NMDA receptors and is expressed postsynaptically. / GluN2C/D antagonists did not block t-LTD at horizontal cross-columnar layer 2/3-to-layer 2/3 synapses, which was blocked by a GluN2B antagonist instead.