The stratum griseum superficiale (SGS) of the superior colliculus contains a high concentration of the recently described GABA(C) receptor. In a previous study, it was postulated that activation of these receptors on inhibitory interneurons functions to disinhibit projection cells that relay visual information to the thalamus and brainstem. To test this model, we used in vitro whole-cell patch-...

The anatomy of the hippocampal region has been studied intensely in rodents since Cajal (1911) and his pupil, Lorente de N6 (1934), carried out their classic slUdies using the Golgi method. In recent years, the cytoarchitecture and connections of the hippocampal region have been further elucidated by the work of Blackstad (1956, 1958), Raisman et al. (1965, 1966) and Hjorth-Simonsen (1972, 1973...

Stratum griseum superficiale (SGS) of the superior colliculus receives a dense cholinergic input from the parabigeminal nucleus. In this study, we examined in vitro the modulatory influence of acetylcholine (ACh) on the responses of SGS neurons that project to the visual thalamus in the rat. We used whole-cell patch-clamp recording to measure the responses of these projection neurons to electri...

We have studied the development of NADPH-diaphorase activity in the retinorecipient layers of the superior colliculus (SC) in rats from embryonic day 17 to adulthood, during aging, and following neonatal tetrodotoxin injection or unilateral eye removal in the neonatal or in the adult animal. In the superficial SC, NADPH-d activity is first seen in neurons on postnatal day (P) 4; over the next t...

Intracellular recording, receptive field mapping, and horseradish peroxidase (HRP) injection techniques were used to determine the structural and functional characteristics of neurons in the superficial laminae (stratum griseum superficiale and stratum opticum) of the hamster's superior colliculus (SC). Fifty-nine neurons (from 38 different hamsters) were successfully characterized, injected wi...

Type I cannabinoid receptor (CB1) is a G-protein coupled receptor with a widespread distribution in the central nervous system in mammals. In a urodele amphibian, the rough-skinned newt (Taricha granulosa), recent evidence indicates that endogenous cannabinoids (endocannabinoids) mediate behavioral responses to acute stress and electrophysiological responses to corticosterone. To identify possi...

The blood feeding of mosquitoes and black flies from Hereford cattle and ponies treated with commercial formulations of permethrin was evaluated using an animal enclosure trap sample system that allowed comparison of insect blood-feeding levels between treated and nontreated animals. Blood feeding of both Aedes dorsalis Meigen and A. melanimon Dyar from heifers treated with pour-on concentrate ...

Immunohistochemical methods have been used to determine the distribution of macroglia and myelin in the normal rat superior colliculus (SC) and in grafts of fetal tectal tissue. The fetal tissue was derived from 15 day-old (E15) rat embryos and was transplanted onto the midbrain of newborn host rats of the same (PVG/c) strain. Antibodies to glial fibrillary acidic protein (GFAP) and carbonic an...

Retinal axons were labeled in the retina and optic nerve with horseradish peroxidase and traced in tectal whole-mounts. The typical network formed by retinal fibers in the five retinorecipient layers of tectum is illustrated in camera lucida drawings. Three size classes of terminal arbors were identified in the Stratum fibrosum et griseum superficiale (SFGS)-ca. 34 X 52, ca. 103 X 150, and ca. ...

seem to be affected very dramatically and can subserve foveal vision as well. Have you any ideas on what this cortical input is doing as well as on the anatomy of the lower layers of the colliculus about which you haven't talked but which may clarify some things? LUND: That really is puzzling. I think it highly unlikely that there is a major direct optic projection to the rostral colliculus. It...