A "Topic" is a term that appears under a "Category" in the Music Information Center. These appear on the righthand side of the MIC after selecting one of the categories on the left.
#Adding
Adding a topic to a category requires creating a Music Information Node and tagging that node to both the category and the topics that you want to appear under that category. Multiple Music Information nodes can be tagged to a category and a Music Information node can also be tagged to multiple categories.
To remove a topic from a category, untag that term from the Music Information Node where it was tagged.
#Adding a new term to the site.
If the topic you want to appear in the MIC does not exist in the CNMAT taxonomy, you will need to add it. Read about adding new terms [http://cnmat.berkeley.edu/node/9071|here]. Be sure to include a definition of the term.