Mental imagery or hallucination?

I sometimes experience involuntary images of things that I’ve seen throughout the day or in the past appearing in front of me like a hallucination but it doesn’t feel like a hallucination as they only last a couple of seconds and they don’t appear solid like it’s there. they’re always see-through in appearance. can everyone here visualize a 3d object in front of them with their eyes open? does the visualized object appear solid in your sight and can everyone do this? has this kind of imagery ever become intrusive? I was diagnose with mild OCD in the past. don’t know if its my OCD acting up again.

A big welcome to our community! What you describe is something I haven’t heard of before but we’ll see if any other folks here have. Are you on any medications that could be causing that effect? Have you discussed it with any Drs, ie//neurologist. I would think there would be some pretty good interest as it does seem to be an uncommon thing. Presenting with something that makes medical people curios is often a good thing! Take Care, John.

Hi. My daughter has an intracranial AVM on her splenium and she used to get hi g of hallucinations and feelings that she had been stabbed etc. I put it down to her mental health. I have spoken to camhs but not the neurologist.

does her hallucinations happen often? because mine don’t always happen frequently and they don’t feel like hallucinations to me as they don’t appear solid, more like vivid mental imagery but i could be wrong.

They started about 2 years ago. She hasn’t told me about them recently so I think they have stopped


Hi! Welcome to the forum. I don’t know anything about this sort of thing, so I’m going to give a couple of examples that I know of and let you see if there is any connection to what is going on with you. If you think there is something going on, I think you need to see a neurologist.

Story 1. Oliver Sacks was an eminent neurologist in Brooklyn or the Bronx in the US. He was the doctor in the film “Awakenings” (though the character in that film was given the name Sayer, I think). He wrote a book called The Man Who Mistook His Wife For A Hat, which is a collection of neurological stories, which I’ve read and enjoy.

The first story is about a patient who has issues with his eyesight. At least, he had difficulty with perceiving certain things. When given a sight test, he was 20:20. However, Dr Sacks’ analysis of his patient was that he had developed a visual agnosia, which meant that he had lost the ability to match shapes to what they were. As a consequence of that, his brain would try to make sense of what he could see and would present possible answers. Consequently, for some reason, on one occasion, at the end of their meeting with Dr Sacks the patient got up to leave and looked for his hat. His brain saw the shapes on the chair next to him and presented them to him as a hat, so he grasped it and tried to pick it up. It turned out that it wasn’t in fact his hat, but his wife.

Now, this story shows someone with quite an advanced deficit with the part of the brain that deals with “gnosis” – the knowing that an object is something, rather than just a shape – and other examples in that story show how advanced an issue the patient had.

Story 2. One of my elderly relatives has vascular dementia. It has lots of effects on them but one is perhaps relevant here. When they are sitting in their lounge, they can see all the way down the street. The problem that they have is that they can’t make out the distant shapes of what is going on at the end of the street, perhaps. So in the same way that when it is dark at night and you look out into the gloom, you see things that are not there, they see things that are not there in daytime. I know as a child, the lumps and bumps in my bedspread were enough for me to see a crocodile crawling up the covers in the dark, or the pattern and folds of material turned into a face hiding behind the curtain, etc. Our brains do this pattern-matching activity and present answers to us.

With my elderly relative, I think they are also starting to have a bit of an issue with that recognition part of their brain, that when a tree bows in the wind, they see a person walking at an odd angle in the street, or a car passing at the end of the road tempts them to see an aeroplane flying at nearly ground level. They know these things are not right and it worries them but it is probably a trick of the brain, doing the same as in story 1, that the pattern-matching of shapes to what they really are is not as good as it used to be and images of improbable things are being presented.

So… I wonder if your AVM is affecting the same part of your brain and is starting to present images of the wrong things to you.

As I say, I’ve no idea. I just know the one story and I know my relative sees things that we know aren’t there. I think it’s something to take up with a neurologist if it bothers you. I’m sure there could be other good reasons, too. So my ideas above may well be irrelevant: I’m not a doctor.

I do hope this helps. Very best wishes,


If I could make a self-diagnosis of what I’m experiencing, I say that I’m the one that’s imagining or visualizing these things but they have become a bit intrusive and out of my control at times. I don’t really feel that it’s a hallucination since they don’t look solid and only last a couple of seconds.

Hi Sam,

I’ve not had this, and it doesn’t describe in the book that I’ve read how these things appear but it strikes me that each individual part of the brain does a specific thing and if your AVM has affected the part of your brain that does this pattern-matching, then I don’t know how long it would present to you that what you can see is x before moving on to decide to decode it as y.

If it bothers you, it feels to me like a conversation to have with your primary care doctor and possibly a neurologist.

Very best wishes


There is an interesting book called Phantoms in the Brain: Probing the Mysteries of the Human Mind by Sandra Blakeslee and V. S. Ramachandran that describes a person with an AVM who sees cartoon characters within her visual field. I definitely think it is possible that you could be seeing objects. Neuroscience is still catching up. Every person’s experience is different in this respect.

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