I felt a Funeral, in my Brain (Personal Reflection)

I found this poem very confusing at first. Dickinson metaphorically compares her transition from sanity to mental chaos with that of a funeral. The funeral, in her brain, is the loss of reason and replacement with insantity. Her diction reveals this metaphor in the first line "I felt a Funeral, in my Brain." Personally, I enjoyed observing this transition through her metaphorical images of the casket plunging into the ground when the "Plank in Reason" breaks. The cutoff at the end of the poem added to this effect of the person's lack of communication with the rest of the world that coincided with her insanity. However, one thing that I found strange was her capitalization of certain words while leaving others normal. Was this a way she signified their importance or just pure randomness? Anyway, the poem demonstrated very well each stage in the process starting with the failure of reason leading to the eventual insanity of the person.