Table 2.

Phasic responses of VTA neurons to somato-sensory stimuli and cocaine

Parameters		Long-spike	Short-spike
Tail-press
	-excitation	22 (66.7±8.2%)	21 (60.0±8.3%)
	-inhibition	0	10 (28.6±7.6%)*
	-no response	11 (33.3±8.2%)	4 (11.4.5±4%)*
	-total	33 (100.00%)	35 (100.00%)
Cocaine
	-excitation	10 (62.5±12.1%)	19 (70.4±8.8%)
	-inhibition	0	0
	-no response	6 (37.5±12.1%)	8 (29.6±8.8%)
	-total	16 (100.00%)	27 (100.00%)

For both tail-press and cocaine, a response’s criterion was is one or more 1-s discharge rate values either higher (excitation) or lower (inhibition) than each of 20 1-s values in pre-stimulus baseline (see Methods for details). Asterisks show significant differences between groups

^*p<0.05.