A method of morphological identification of individual neurons in the brain in vivo and after fixation.

Pyramidal neurons from layers III and V of the cat brain cortex being stained with methylene blue are revealed in vivo in specially prepared cortex specimen by means of contact micro-objectives in the reflected light. Small pieces of the brain tissue with identified neurons are excised after their fixation in situ under visual control and are placed in special grid-baskets in definite positions. Orientated and fixed by the basket's edges a bit of tissue is subjected to further histological treatment. This method permits the investigation of the same neurons after fixation by means of histological techniques suited for light or electron microscopy.