1938
Studies on these animal models point to some potential mechanisms that could explain epilepsy and depression comorbidity , such as various components of the dopaminergic , noradrenergic , serotonergic , and GABAergic systems , as well as key brain regions , like the amygdala and hippocampus .
 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