Table 2.

Distribution of AS and SS on spines and dendritic shafts in control cases and AD patients

Group	Type of synapse	Synapses on spine heads	Synapses on spine necks	Synapses on aspiny dendritic shaft	Synapses on spiny dendritic shaft	Total synapses
Control	AS	59.1% (825)	0.5% (7)	19.9% (278)	20.5% (286)	100% (1396)
	SS	7.1% (8)	0.9% (1)	38.4% (43)	53.6% (60)	100% (112)
Alzheimer	AS	50.2% (579)	0.7% (8)	28.0% (323)	21.1% (243)	100% (1153)
	SS	8.8% (9)	1.0% (1)	41.2% (42)	49.0% (50)	100% (102)

Synapses on spines have been sub-divided into those that are established on spine heads and those that are established on spine necks. Moreover, we differentiated between aspiny and spiny dendritic shafts. Data are expressed as percentages with the absolute number of synapses studied given in parentheses. Data for each individual case are represented in Table 2-1. Data expressed as absolute number of synapses were taken from this table to perform contingency tables showed in Table 2-2 and Table 2-3.