Fig. 1

Experimental design and representative images of immunolabeled markers, lesion, and sampling location. a Experimental workflow as described in Moore et al., [12]. The brains were harvested 14 to 16 weeks after the surgery using two methods: (a1) During Krebs buffer perfusion, 1–2 cm fresh tissue block was harvested from the ventral perilesional M1 and PMC, with caudal 1/4 processed for qPCR and the rostral ¾ was cut into 300 µm acute slices for whole-cell patch-clamp recording and intracellular filling of layer 3 pyramidal cells. (a2) The remainder of the brain containing the lesion and dorsal PMC was fixed with 4% paraformaldehyde then cut into serial coronal sections for IHC labeling. b, c Photographs showing the hand representation (sites with black dots) mapped with electrical stimulation of M1 and (b) the lateral surface of the fixed brain (c) showing the M1 and PMC, with the lesion area (blue arrow), and locations of sampled sites in dorsal (dPMC) and ventral (vPMC taken out) PMC, as described in previous studies [12, 14]. Sulci: A, arcuate; C, central (black arrow); L, lateral; axes: D, dorsal; V, ventral; M, medial; L, lateral. d Photograph of ipsilesional hemisphere and coronal section (gray matter with intact pia indicated with black line) thorough the surgical lesion (lesion volume is outlined with blue dotted line, lesion surface indicated with red line and depth measurement with orange arrow), with black arrows indicating perilesional M1 underlying the lesion, and adjacent dorsal PMC. e Example confocal images of multi-channel IHC fluorescence labeling tiled (4 × low mag yellow inset shown in 20×) in M1 and PMC from veh or EV group. Sampling sites are shown in yellow (M1) and white (PMC). f-g Example maximum z-projection of high-resolution confocal images used for analyses: f Representative pyramidal neurons intracellularly filled with 1% biocytin and visualized with Alexa 488 streptavidin conjugate, together with immunolabeled microglia. g Representative images showing immunolabelling of synaptic, microglial, and complement markers that were immuno-labeled included