What resolves this contention: In-vivo functional necessity (silencing experime…

What resolves this contention: In-vivo functional necessity (silencing experiment) vs. in-vitro synaptic sufficiency (CRACM) of the M1→S1 corticocortical pathway during behavior. / In awake mouse wS1, axonal silencing of vM1 inputs does NOT alter whisking-related spike rate or membrane-potential dynamics in S1, indicating that during spontaneous whisking the M1→S1 translaminar pathway does not transmit a behavior-driving signal. / M1 axons in S1 make strong monosynaptic excitatory contacts onto L5 PT (and IT) pyramidal neurons that drive action potentials and exhibit projection-class-specific short-term plasticity — implying a functionally significant M1→S1 translaminar drive.