Table 1.

Quantitative strengths of specific input connections to proximal, intermediate, and distal CA1 pyramidal neurons

	Ipsilateral			Contralateral			Ipsilateral		Ipsilateral		Contralateral			Median Raphe	MS-DB
	CA3a	CA3b	CA3c	CA3a	CA3b	CA3c	LEC	MEC	Sub	Pre/Para Sub	pCA1	mCA1	dCA1
Proximal CA1
Average CSI	4.00	3.14	1.89	1.79	1.20	0.70	0.49	1.51	0.31	0.53	0.00	0.00	0.01	0.12	1.69
SE	0.55	0.31	0.23	0.13	0.11	0.14	0.08	0.24	0.04	0.11	0.00	0.00	0.01	0.01	0.23
n	6			5			6		8		5			5	5
Intermediate CA1
Average CSI	2.61	2.32	1.06	1.15	1.03	0.51	0.62	0.87	0.55	0.28	0.01	0.04	0.13	0.05	0.88
SE	0.50	0.41	0.24	0.13	0.13	0.05	0.04	0.10	0.05	0.04	0.01	0.02	0.06	0.01	0.06
n	5			5			6		7		5			5	5
Distal CA1
Average CSI	0.61	1.23	0.60	0.34	0.76	0.43	0.98	0.45	1.33	0.24	0.01	0.08	0.23	0.03	1.43
SE	0.10	0.13	0.08	0.12	0.19	0.14	0.11	0.07	0.27	0.06	0.00	0.02	0.04	0.01	0.17
n	5			5			6		7		5			5	6

Note that the input connection strength index (CSI) is defined as the ratio of the number of labeled presynaptic neurons in a specified structure versus the number of starter neurons. In each injection condition, 5–6 cases of Picospritzer-injected brains are taken for quantifications. The average number of starter neurons of Picospritzer injected cases are 126 ± 17 (proximal CA1 injections), 136 ± 32 (intermediate CA1 injections), and 80 ± 14 (distal CA1 injections). In addition, 4 cases of iontophoretic injected brains for each condition are included for quantification. The average numbers of starter neurons of iontophoretic injected cases are 21 ± 4 (proximal CA1 injections), 27 ± 5 (intermediate CA1 injections), and 26 ± 4 (distal CA1 injections). pCA1, proximal CA1; mCA1, intermediate CA1; dCA1, distal CA1; MS-DB, medial septum and diagonal band. See Table 1-1 for detailed statistical comparison results.