What resolves this contention: Whether IT and PT corticostriatal inputs onto SP…

What resolves this contention: Whether IT and PT corticostriatal inputs onto SPNs are functionally equivalent. The 2008 antidromic-identification study argues IT supplies the dominant excitation with PT being weaker (and the two pathways producing identical SPN latencies); a 2022 optogenetic dissection finds a PT-specific polysynaptic amplification through cholinergic interneurons that is absent for IT, implying functionally distinct IT vs PT corticostriatal channels. / Firstly, although the conduction velocity of PT neurons is 4.6 times faster than that of IT neurons, identified striatopallidal and striatonigral neurons exhibit identical latencies of their spike responses to electrical stimulation of the ipsilateral cortex. / These biphasic signals are a hallmark of PT, but not IT, corticostriatal inputs, due to a stronger relative input from PT neurons to ChIs.