At least one thalamotelencephalic pathway in cartilaginous fishes projects to the medial pallium.
Injections of horseradish peroxidase into the medial pallium of the spiny dogfish, Squalus acanthias, retrogradely labeled cells in the superficial portion of the dorsal pallium, the medial pallium and the septal area of the telencephalon, and in the posterior tubercle and posterior lateral thalamic nucleus of the diencephalon. Except for the septal projection, all projections to the medial pallium are bilateral. Labeled fibers could be traced from the injection site to caudal telencephalic levels but not to the hypothalamus. The projection from the posterior lateral thalamic nucleus, which is known to be an electrosensory relay center in ray and skate, provides evidence that at least one ascending thalamotelencephalic pathway in Squalus and perhaps other elasmobranchs terminates in the medial pallium rather than in the dorsal pallium. In this respect Squalus shows striking similarities to amphibians.
D000818:Animals; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000033:anatomy & histology; D004284:Dogfish / Q000033:anatomy & histology*; D005260:Female; D006735:Horseradish Peroxidase; D008297:Male; D009434:Neural Pathways / Q000033:anatomy & histology; D012754:Sharks / Q000033:anatomy & histology*; D013687:Telencephalon / Q000033:anatomy & histology*; D013787:Thalamic Nuclei / Q000033:anatomy & histology*
D006735:Horseradish Peroxidase