Table 2.

Summary of tonic LC stimulation effects on response probability of VPM thalamic and BF cortical neurons

	Thalamus	Cortex
Frequency
Facilitation	26/40 (65.0%)	17/54 (31.5%)
Suppression	12/40 (30.0%)	34/54 (63.0%)
No effect	2/40 (5.0%)	3/54 (5.6%)
Gating	9/34 (26.5%)	21/63 (33.3%)
Current
Facilitation	32/40 (80.0%)	18/54 (33.3%)
Suppression	4/40 (10.0%)	34/54 (63.0%)
No effect	4/40 (10.0%)	2/54 (3.7%)
Gating	13/34 (38.2%)	26/63 (41.3%)

Thalamic and cortical cell responses were categorized according to the nature of the neuromodulatory effect observed during LC stimulation. Facilitation or suppression was declared if a significant increase or decrease in the probability of response was observed at any frequency or current of LC stimulation, respectively. For those neurons that were not initially responsive to whisker pad stimulation, gating was declared if a significant response emerged during tonic LC stimulation.