TABLE 1.

Compositions of extracellular recording solutions (in mm)

	Solutions
	NaCl	KCl	MgCl2	CaCl2	HEPES	Glucose
Standard	147	2	1	2	10	13
147 NaCl + 2 CaCl2 + 1 MgCl2	147	0	1	2	10	13
147 NaCl (no CaCl2)	147	0	0	0	10	24
147 NaCl + 0.1 CaCl2	147	0	0	0.1	10	24
147 NaCl + 0.3 CaCl2	147	0	0	0.3	10	22
147 NaCl + 1 CaCl2	147	0	0	1	10	21
147 NaCl + 2 CaCl2	147	0	0	2	10	17
147 NaCl + 3 CaCl2	147	0	0	3	10	11
147 NaCl + 10 CaCl2	147	0	0	10	10	0
147 NaCl + 2 MgCl2	147	0	2	0	10	20
110 CaCl2	0	0	0	110	10	24
110 MgCl2	0	0	110	0	10	24