"I felt a Funeral, in my Brain," like many of the Dickinson's poems, deals with the subject of death. In particular, she likes to deal with the subject of the moment of death and burial. For example, check out her poems "I died for Beauty – but was scarce" or Shmoop's analysis of "I heard a Fly buzz – when I died –". It seems that Dickinson was either afraid of death, or really curious about it, or maybe a mix of both. She seemed to believe that people went through death-like experiences throughout their lives. One of the central questions in this poem is whether death is a metaphor for some other experience.
The poem is written from the perspective of a dead person in a casket, and every detail of the poem can be explained along these lines.
"I felt a Funeral, in my Brain" comes about as close to a dream as possible without the poet announcing, "This is a dream I had." The setting shifts with no warning, and the story of the funeral hangs together very loosely. The whole scene takes place inside the speaker's brain, mind, or soul – we're not sure which, or whether these are all the same thing. Her mind is a huge, cavernous place that contains entire worlds. The end of the poem reads like someone waking up from a dream. On top of all that, we're not sure whether the speaker is living or dead. She might be narrating the poem from inside a coffin.
In the world of Dickinson's poem, the mind is a microcosm of the universe as a whole.
The suffering in "I felt a Funeral, in my Brain" is passive. The speaker doesn't seek out a traumatic experience or bring one upon itself. She seems to remain in the same location throughout the poem, until the floor breaks beneath her. It's not clear that she does anything at all. Rather, things are done to her. Specifically, noise. People walk on her, and then she hears a loud drumbeat until she goes numb. Even after going numb, she seems capable of hearing and feeling things. Some readers think that "I felt a Funeral, in my Brain" is about depression.
The "treading" and "beating" that the speaker experiences is the pulsing of her own heart.
You'd think that in a poem about a funeral, the dead person would do the haunting. But in "I felt a Funeral, in my Brain," religion – specifically New England Protestantism – does the haunting. Not literally, of course. But the religious service in this poem is anything but a source of peace and comfort. Religion keeps invading on her space. Although church is supposed to bring a sense of community into one's life, the speaker of this poem feels isolated and abandoned.
"I felt a Funeral, in my Brain" is not about traditional religion. Dickinson treats the funeral as a secular ritual.