Comparison with drug actions in other studies.

This table summarizes the data from the present study and three earlier studies in healthy male volunteers. Plus signs (+) indicate brain regions showing significant activation; minus signs (−) indicate brain regions showing significant deactivation. Numbers indicate count of discreet brain sites within each named subregion.Columns:“Pain” Brain regions showing statistically significant BOLD signal changes in our study of noxious stimulation [42]. Note that the count of discrete brain sites within each named subregion is not shown here.“Nalb-Sal.” Consists of two subcolumns “Activ.” and “Connect.”“Activ.” Brain regions showing statistically significant BOLD signal changes in response to saline followed by nalbuphine (Table 1).“Connect.” Brain regions showing statistically significant functional connectivity with respect to caudate (Table 4). Numbers indicate count of discreet brain sites within each named subregion showing functional connectivity. Note that this only occurred in the Nalb-Sal group; no significant connectivity was observed in the Nalb-Nalox group.“Nalb-Nalox” Brain regions showing statistically significant BOLD signal changes in response to naloxone followed by nalbuphine (Table 2).“Morph” Brain regions showing statistically significant BOLD signal changes in our study of morphine [8].“Nalox” Brain regions showing statistically significant BOLD signal changes in our study of naloxone (Borras et al., 2004). Note that the count of discrete brain sites within each named subregion is not shown here.“Contrasts” Consists of two subcolumns “NN>NS” and “NS>NN.” The numbers indicate the count of discreet sites demonstrating significant differences in BOLD activation/deactivation between the two treatments (Table 3); therefore, individual sites in may or may not be found in Tables 1 or 2.“NN>NS” Regions where naloxone followed by nalbuphine showed significantly greater activation than saline followed by nalbuphine.“NS>NN” Regions where saline followed by nalbuphine showed significantly greater activation than naloxone followed by nalbuphine.All studies represented in the table were performed using the 3T Siemens scanner, and the studies for morphine and naloxone used the same infusion protocol as the current study.