Journal: The Journal of Comparative Neurology
Article Title: Multiple Longitudinal Tracts in the Cephalopod Arm Sensorimotor System
doi: 10.1002/cne.70165
Figure Lengend Snippet: Longitudinal tracts in the oral neuropil. (a) Schematic of a longitudinal axial nerve cord (ANC) demonstrating the trajectories of the internal longitudinal tract (iLT, green) and the oral longitudinal tract (oLT, red) as the tracts travel from sucker to sucker. * denotes ANC enlargements for suckers on the same side. + denotes ANC enlargement for suckers on the opposite side. (b) Diagram of a horizontal section of the ANC demonstrating the paths of the oLT (red) and iLT (green) in the oral portion of the ANC. (c) Maximum projection of a transverse ANC wholemount stained for SMI‐31 (cyan). The iLT is outlined with a yellow dashed line as it crosses the midline. Key indicates transverse plane of section. Scale bar: 100 µm. (d) Horizontal section through the oral NP stained for SMI‐31 (cyan), F‐actin (magenta), and DAPI (gray). The iLT, marked by yellow arrowheads, follows the internal side of the ANC. (e) Maximum projection of a transverse ANC wholemount stained for SMI‐31 (cyan). The oLT is outlined with a white dashed line. Key indicates transverse plane of section. Scale bar: 100 µm. (f) Horizontal section through the oral NP stained for SMI‐31 (cyan), F‐actin (magenta), and DAPI (gray). The oLT, marked by white arrowheads, is positioned close to the midline, located oral to the iLT, and oscillates through ANC enlargements. Keys indicate horizontal plane of section. Scale bar: 150 µm. (g, h) The oLT bifurcates at the transition between sucker enlargements. White arrowheads mark the oral branch of the oLT, and white arrows mark the aboral branch of the oLT. See loop of the oLT in (a). (g) Injection of dextran labeling the oLT at the transition between sucker enlargements. Keys indicate plane of section and field of view. Ovals on keys indicate injection site. (h) Maximum projection of a transverse ANC wholemount stained for SMI‐31 (cyan) at the transition between sucker enlargements. The iLT is outlined with a yellow dashed line. The aboral oLT trunk loops over the iLT. The aboral and oral oLT branches connect to the oLT on the other side. Scale bars: 100 µm. ANC, axial nerve cord; ExA, external side of the axial nerve cord; InA, internal side of the axial nerve cord; iLT, internal longitudinal tract; NP, neuropil; oLT, oral longitudinal tract.
Article Snippet: Clone SMI‐31 reacts with a phosphorylated epitope of neurofilament in mammals and neurofilament 220 in squid (Sternberger and Sternberger ; Grant et al. ; Grant and Pant ), and it has been employed successfully in octopus arm tissue (Olson, Schulz, et al. ).
Techniques: Staining, Injection, Labeling