Jones Lang LaSalle shows that over the last 20 years, the Los Angeles Westside had much more volatile rents than Downtown Los Angeles.  JLL claims that the Westside has startup tenants, while Downtown Los Angeles has more established tenants.  The gap between the two widens in booms and narrows in busts.  A 30% spread of Westside rents over Downtown rents predicts recession, according to JLL.  You can enlarge the chart by clicking on it.