26293
RESULTS : Risk level ( number of pumps ) modulated brain activation in the right dorsolateral and ventrolateral prefrontal cortices more in smokers than in nonsmokers , and smoking severity ( Heaviness of Smoking Index ) was positively related to this modulation in an adjacent frontal region .
 None
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 None