Structure of the pecten neuropil pathway and its innervation by bimodal peg afferents in two scorpion species
Fig 8
Projection pattern of single pegs within the pecten neuropil of Mesobuthus eupeus.
Maximum projections of cLSM stacks. Synapsin-immunoreactivity (grey (not shown in D-F)), anterograde tracing (green) and nuclei staining (magenta). (A-C) Horizontal serial sections arranged from ventral (A) to dorsal (C). (D-F) Insets of A, B and C in a higher magnification. (A) I Innervation is restricted mainly to the lateral part of the posterior pecten neuropil 2 (PPN2) ventrally. (B, C) Gradual dorsal innervation of lateral PPN1 areas. (D) Lateral tract (LT) projects anteriorly from the margin of the neuropil (white arrowhead). (E) Small tract (CT) connects PPN1 and PPN2 (white arrowhead). (F) Lateral tract proceeds anteriorly (white arrowhead). (G) Innervation pattern of distal peg afferents in the right pecten neuropil and a proximal peg in the left pecten neuropil (horizontal view). Proximal pegs project medially into the PPN2, whereas distal pegs project laterally towards PPN1 and PPN2. (H) Sagittal view of the posterior part of the synganglion with focus on PPN which protrudes ventrally. The pecten nerve splits into two tracts. The dorsal tract innervates the postero-ventral synganglion and proceeds anteriorly. The ventral tract innervates PPN dorso-laterally and exits the neuropil anteriorly. (I) Sagittal view of a rather lateral section. Innervation of the PPN is restricted to its dorsal part. Abbreviations: a: anterior; CT: connecting tract; d: dorsal; LT: lateral tract; p: posterior, PPN1-3: posterior pecten neuropil 1–3; v: ventral.