[Neurons and neuronal associations in the frontal cortex in the monkey].

The Golgi and Golgi-Kopsh methods show that pyramidal cells in layers II-IV of the prefrontal cortex in Macaca rhesus have numerous, mainly recurrent, collaterals of axons which realize vertical connections. Three groups of stellate basket cells which have different axon collateral directions were identified. They unite the pyramidal cells both in horizontal (modules) and vertical (micromodules) directions. Arrangements of 14-16 pyramidal neurons which form dendritic bundles were found. Local neuronal groups with U-shape axons were observed near the bundles.