20437
In contrast , the hallucinogens produced a robust reduction in the power of low ( 40 - 60 Hz ) , but not high gamma oscillations ( 70 - 90 Hz ) .
 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