Non-Pyramidal Neurons of Layers I–III in the Dog’s Cerebral Cortex (Parietal Lobe)

Abstract

In an attempt to classify neurons in the upper layers of the cerebral cortex according to modern nomenclature based on Golgi impregnations, non-pyramidal neurons in layers II and III of the dog’s cerebral cortex have been categorized into thirteen types: (1) large double-bouquet cells with long ascending and descending axons (type I double-bouquet cells); (2) bipolar neurons; (3) multipolar neurons with long tufted descending axons (type II double-bouquet cells); (4) neurons with long ascending axons; (5) neurons with superficial axon plexuses; (6) elongated large multipolar neurons with extended generalized axonal arborizations; (7) neurons with long descending axons; (8) small bi-tufted neurons with short ascending, descending or local axons; (9) small multipolar neurons with short ascending, descending or local axons; (10) multipolar neurons with local or extended axonal arborizations usually forming arcades (some of them also with a long descending axon); (11) basket cells; (12) neurogliaform neurons, and (13) chandelier cells. Neurons in the molecular layer were horizontal cells and multipolar neurons with short axons. These data have been compared with those described in other species to provide a provisional classification of non-pyramidal neurons located in the upper layers of the cerebral cortex.