[Afferent connections of the visual cortex in the albino mouse]

The afferent connections of the visual cortex of the albino mouse have been studied with the aid of the enzyme Horseradish peroxidase (HRP). Ipsilateral HRP-positive cells have been found in areas 17, 18a, 18b and the temporal cortex; in the contralateral cortex, they were located in areas 17, 18a and in the temporal cortex, the greatest number of labeled cells being situated near the 17/18a border. Apart from the Nucleus dorsalis corporis geniculati, more thalamic nuclei project to the visual cortex; the Nucleus lateralis thalami, pars posterior contains regularly positive cells, whereas other nuclei (Nucleus lateralis thalami, Nucleus medialis thalami, pars lateralis, Nucleus ventralis thalami, pars lateralis and pars medialis) only in some cases show labeled cells. Sporadically, a few labeled cells were observed in the Nuclei medialis and lateralis tractus optici, Nucleus praetectalis thalami and the Nucleus centralis medialis. The afferent connections from the brain stem have not always been visualized. The most frequent afferent connections come from the Nucleus dorsalis tegmenti pontis, followed by the Nucleus reticularis tegmenti pontis and the Nucleus Locus coerulei. Occasionally, a few HRP-positive cells were found in the Nucleus ventralis tegmenti, Nucleus raphe dorsalis, Nucleus parabrachialis lateralis and in the Nucleus centralis superior. The morphology of the projecting neurons in different centres was studied and compared after HRP-filling and after Golgi-impregnation.