Southend sit eight points adrift of the automatic promotion spots, and Brown will be keen to at least try and cut that gap - and has used the final day of the loan window to improve his squad.
The Southend Echo report that Nottingham Forest winger McLaughlin has agreed a deal to join Southend until the end of the season.
The Irish wide man, 24, joined Forest from Derry City in 2013, but has failed to really make an impact at the City Ground, joining Bristol City on loan last season and Notts County on loan this season.
He returned to Forest in January and actually had a run in the team under Stuart Pearce, but since his sacking, McLaughlin hasn't featured at all, being frozen out by new boss Dougie Freedman.
McLaughlin still has a year to run on his contract at Forest, but looks unlikely to have a long-term future at the club - and this latest loan move could be his last chance to impress Freedman and co, having not managed to so far.