What causes flashbacks if they are not traumatic? Could it be deja vu?

Brain is fascinating. Think of brain as two.Pound computer with mega data processing capabilities not known to neuroscientist yet though we claim amydgla and hippocampus have become the focus of research as more vets r coming with flash backs some with and without trauma. Brain is much more complicated and registers every second in a memory in a digital file appears as flashback join us with patrick kennedynext week.