How many papers were published in 2011 in the journal whose short name is "Mol Brain"?
in 2011 refers to Year = 2011; 'Mol Brain' is the ShortName of journal
SELECT COUNT(T2.Id) FROM Journal AS T1 INNER JOIN Paper AS T2 ON T1.Id = T2.JournalId WHERE T2.Year = 2011 AND T1.ShortName = 'Mol Brain'