A computerized method of determining the number of synaptic contacts in a volume of cerebral cortex

A computerized flying‐spot scanning device has been used to count the number of synaptic contacts in neural tissue stained with ethanolic phosphotungstic acid (E‐PTA). The ability of the computer to idealize the irregular synaptic contacts as solid disks by modifying the information gleaned from scanning the preparation allows the stereological principle of Weibel & Gomez to be used to calculate the number of E‐PTA stained synaptic contacts per unit volume of tissue. This technique represents a significant improvement over the time necessary for making similar quantitative determinations manually. 1972 Blackwell Science Ltd