Visual, lateral line, and auditory ascending pathways to the dorsal telencephalic area through the rostrolateral region of the lateral preglomerular nucleus in cyprinids

Fiber connections of the rostrolateral region of the lateral preglomerular nucleus (PG1r) were studied by tract-tracing methods in carp and goldfish. The PG1r receives fibers from the optic tectum, ventrolateral nucleus of semicircular torus, ventromedial thalamic nucleus, medial pretoral nucleus, anterior tuberal nucleus, subglomerular nucleus, and (unexpectedly) also from the retina. Dendritic morphology, of tectopreglomerular neurons suggests that they receive retinal inputs. The PG1r can be further subdivided into dorsal (PG1r-d) and ventral (PG1r-v) zones, both of which are composed of somata and neuropil layers. Retinal and tectal fibers terminate mostly in the neuropil layer of the PG1r-d with the retinal terminals concentrated medially and tectal terminals laterally. Lateral line toral fibers terminate mainly in a lateral portion and ventromedial thalamic fibers in a medial portion of the somata layer of the PG1r-d. Auditory fibers from the medial pretoral nucleus and anterior tuberal nucleus terminate in the PG1r-v. The central nucleus of the semicircular torus also projects sparse fibers to the PG1r-v. The PG1r projects to the lateral, central, and medial parts of the dorsal telencephalic area, and the latter telencephalic part sends descending fibers to the PG1r. Differential distribution patterns of PG1r-d and PG1r-v fibers are noted within the dorsal telencephalic parts, suggesting that different