The nucleus geniculatus lateralis pars ventralis (GLv) is a prominent retinal target in all amniotes. In birds, it is in receipt of a dense and topographically organized retinal projection. The GLv is also the target of substantial and topographically organized projections from the optic tectum and the visual wulst (Hyperpallium). Tectal and retinal afferents terminate homotopically within the external GLv-neuropil. Efferents from the GLv follow a descending course through the tegmentum, and can be traced into the medial pontine nucleus. At present, the cells of origin of the Tecto-GLv projection are only partially described. Here we have characterized the laminar location, morphology, projection pattern and neurochemical identity of these cells, by means of neural tracer injections and intracellular fillings in slice preparations and extracellular tracer injections in-vivo. The Tecto-GLv projection arises from a distinct subset of layer 10 bipolar neurons, whose apical dendrites show a complex transverse arborization at the level of layer 7. Axons of these bipolar cells arise from the apical dendrites and follow a course through the optic tract to finally form very fine and restricted terminal endings inside the GLv-neuropil. Double label experiments showed that these bipolar cells were ChAT immunoreactive. Our results strongly suggest that Tecto-GLv neurons form a pathway by which integrated tectal activity rapidly feeds back to the GLv and exerts a focal cholinergic modulation of incoming retinal inputs.

The results suggest that PPD-12 is influenced directly and indirectly through PPD-6 by APD, but that this effect depends upon risk and protective factors, especially on the combined effects of resilience and DSC. The key finding of our study is the moderating (i.e. weakening) effect of resilience on the relationship between DSC and depression. Resilience and DSC may be an important issue for depression prevention and treatment programs in the peripartum period.

No abstract