Cortico-cortical and subcortico-cortical afferent connection of the rabbit's primary visual cortex. A horseradish peroxidase study.

Neuroanatomical studies were carried out on the visual system of the adult rabbit brain. Either horseradish peroxidase (HRP) or wheat germ agglutinine-horseradish peroxidase (WGA-HRP) was injected into the area occipitalis 1. Several cortico-cortical, ipsi- and contralateral, and subcortico-cortical projections were demonstrated. In the ipsilateral telencephalon several patches of labelled cell groups, some single HRP-positive cell bodies and some labelled fibres were observed in the area retrosplenialis granularis dorsalis, the areas occipitales, the areas temporales, the area perirhinalis, the area entorhinalis, the area praecentralis 1, the regio cingularis 1 and in the regio diagonalis, as well as in the dorsal part of the claustrum. Efferent preterminal fibres and terminal knobs were seen in the nucleus caudatus. Contralaterally, groups of labelled cell bodies and single HRP-positive neurons were found in the area retrosplenialis granularis dorsalis, the areas occipitales and the areas temporales. In the ipsilateral diencephalon, labelled cell bodies were observed in the corpus geniculatum laterale (pars dorsalis and ventralis), the nucleus lateralis thalami, the nucleus reticularis thalami and in nonspecific nuclei of the midline. Contralaterally, very few labelled cell bodies were seen in the nonspecific nuclei of the midline. Some labelled cell bodies were observed in the ipsilateral substantia griseum centrale and in the nucleus reticularis mesencephali. Numerous anterogradely labelled preterminal fibres and terminal knobs but very few labelled cell bodies were seen in the nucleus praetectalis posterior. In the nucleus of the optic tract and in the colliculus superior, numerous labelled fibres could be observed. In the ipsilateral nuclei pontis numerous labelled fibres were detectable.

Chandelier neurons within the rabbits' cerebral cortex. A Golgi study.

This study has been carried out by light microscopy on 3 Golgi-Kopsch impregnated brains of young adult rabbits. It is shown that chandelier cells exist within the rabbits' cerebral cortex. In the rabbit, the chandelier cell is a medium ranged bipolar interneuron in layer II/III with a characteristic axon which forms a plexus with a diameter of about 350-500 micrometers in the horizontal and 200-350 micrometers in the vertical direction; the end of each ramulus forms the typical "candlestick", a little vertical string of 1-6 boutons on an axon fibre. These boutons form contacts with all parts of pyramidal cells in layer II and the upper part of layer III. Similarities and differences with respect to previous descriptions of these cells in other species are discussed.