Extended Data Fig. 1: Distinct projection targets and morphological differences between PT and IT neurons.
From: Psilocybin’s lasting action requires pyramidal cell types and 5-HT2A receptors
a, To express GFP in IT neurons, we injected AAV-CAG-FLEX-eGFP in the ACAd and medial MOs portion of medial frontal cortex and low titre of the retrogradely transported AAVretro-hSyn-Cre in the contralateral striatum of adult C57BL/6J mice. Post hoc histology and imaging of the GFP fluorescence in coronal sections shows ipsilateral and contralateral projections to various striatal and cortical regions. CP, caudoputamen. b, To express GFP in PT neurons, we injected AAV-CAG-FLEX-eGFP in the ACAd and medial MOs portion of medial frontal cortex and low titre of the retrogradely transported AAVretro-hSyn-Cre in the ipsilateral pons of adult C57BL/6J mice. Post hoc histology and imaging of the GFP fluorescence in coronal sections shows ipsilateral projections to striatum and subcortical regions including the pons (lower rightmost image). c, In vivo two-photon images of apical dendrites from PT and IT neurons targeted to express GFP using retrogradely transported viruses. d, Baseline spine density for all imaged dendrites on Day -3 prior to any psilocybin or saline administration. PT neurons have lower spine density than IT neurons (P < 0.001, two-sample t-test). Yellow, PT neurons. Purple, IT neurons. PT: n = 160 branches from 17 mice. IT: n = 142 branches from 16 mice. e, Similar to (d) for spine head width. PT: n = 1071 spines from 6 mice. IT: n = 615 spines from 5 mice. PT neurons have larger spine head width than IT neurons (P < 0.001, two-sample t-test). ***, p < 0.001. Detailed sample size n values are provided in Methods. Statistical analyses are provided in Supplementary Table 1.
