Don't lose hope just yet! I have it on good word from a UCLA graduate that their committee still has to review applications well into January. Honestly, a lot of programs are probably the same. They probably want to take a break for the holidays and then re-convene to make decisions without the pressure of the holidays.
UMichigan (Neuroscience Direct) finished reviewing their applications last week and extended their invitations by phone last Friday. The few who couldn't be reached by phone will be emailed this week, but otherwise, the admissions coordinator I spoke to said that another round of interview invitations will not be expected...