Table 2.

Estimated population statistics based on published electron microscopy studies

	Head width	Neck width	Length
Median	0.40	0.15	1.36
Mean	0.46	0.15	1.50
Range	0.84	0.42	4.80

Geometric spine measurements (μm) from previously published electron microscopy studies were pooled to generate estimated median, mean, and range values for the population of dendritic spines on hippocampal neurons [10,29,31,36,77].