TABLE 4.

Morphological criteria for identifying VENs (adapted and modified from Banovac et al., 2019).

Morphological feature	Characteristics of VENs	Recommended staining method for optimal assessment
Apical process	Very thick origin (up to 8 μm), very gradual decrease in thickness	Rapid Golgi, Golgi-Cox, or other Golgi modifications that result in quality impregnation of the dendritic tree (possible alternative: intracellular dye injections)
Basal tree bifurcation degree	Low
Basal process thickness	Constant or very gradual decrease
Basal process arborization	High, brush-like (basilar skirt)
Axon origin	End of basal stem	Rapid Golgi or other Golgi modifications that clearly visualize axon origin (possible alternative: intracellular dye injections)
Cell body shape	Long (50–120 μm) and stick-shaped (5–10 μm wide), preferably with clear regional and laminar specificity	Nissl, Golgi, or intracellular dye injections (possible alternatives: NeuN, SMI-32)