23067
We found that networks derived from spinal cord are more sensitive to the toxin than those from frontal cortex ; a concentration of only 10nM produced statistically significant effects on activity from spinal cord networks whereas 50nM was required to alter activity in frontal cortex networks .
 None
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities:  
Answer:
 None