Rare Brain Malfunctions

I recently read an interesting piece on how the brain can malfunction. It really put into perspective exactly how many things the brain does without you even knowing so that you can live your life like a normal person.

There are a lot of ways the brain can screw up, but I’ve chosen three of the ones I find the quirkiest. Hope you enjoy the read!


This particular malfunction is a monothematic delusion where you think that a limb or even an entire side of your body isn’t yours. Whaaaat..

Monothematic delusion means you’re only deluded in one topic (the ownership of your limbs). The disorder is essentially this – despite being able to see exactly how your limb joins with your body and how it is undeniably yours in ownership, you still deny it and make up a reason why it actually isn’t yours. You will think it is someone else’s limb.

It’s suggested that this disorder is caused by damage to the posterior cerebral regions of the cortex. In English, the back part of your brain which has your senses and stuff.

Recent studies have also suggested that damage to the deep cortical regions such as the  posterior insula and sub cortical structures such as the basal ganglia plays a significant role. The basal ganglia is where you have your habits stored. The insula lobe keeps track of where all your body parts are so that you have an awareness of where everything is without having to look. I’ll include a picture so you guys can see.

The part that has your senses is in the sensory homunculus which is mostly in your parietal lobe (orange).

The insula lobe is on the inside somewhere, and the basal ganglia is three pockets, also on the inside. So really this diagram is useless.

Anyway, it’s reported that in some cases, the delusions are so severe that the limb in question is treated as a separate being.

How this actually works can be confusing without an example.

Imagine this, your head is itchy, and you feel someone else scratching your head. Then that same person adjusts your backpack. You look to see who the helpful person is and find out it’s actually someone else’s arm which has been grafted to your body.

There was a reported case where a man thought his arm belonged to a woman called Maria. Please let this not happen to me.

Fregoli Syndrome

The delusion of doubles is an interesting one. It’s the disorder where you think that different people are in fact the same person in different disguises.

Apparently, a person who suffers from this delusion can also replicate places, objects and events. This is explained by associative nodes in the brain that link information together.

The disorder is named after Leopoldo Fregoli, an Italian actor who could change costumes quickly during his stage acts.

The Fregoli Syndrome is actually one of several Delusional Misidentification Syndromes, which are caused by many things.

The main one is obviously brain injury. Fregoli Syndrome can be caused by damage to the right frontal and left temporo-parietal areas. These are the junctions between the temporal and parietal lobes. Temporal lobe does speech and vision as well as long-term memory, and the parietal lobe does the other sensory stuff.

It can also be caused by lesions in the right temporal lobe and the fusiform gyrus, which gives you face recognition among other things.

The disorder has different degrees of severity. Some don’t know who is following them, they just think that everyone looks really familiar or looks similar. Some think that they are being stalked by one person who is a master of disguise. That is damn scary if you imagine having it, seeing someone you know walk out of a house, and then see that same person brushing past you AND reading the newspaper AND selling you coffee. Then you go home to your partner and that same person is waiting for you instead. Head asplode.


Mirrored-self Misidentification

This one isn’t as well documented as the previous ones, so there won’t be that much info on it. Essentially, the person who suffers from the disorder looks in the mirror and sees someone else instead. They misidentify themselves in the mirror.

The article where I read about it said that it’s a breakdown of the part of the brain that understands how reflections work. So instead of recognizing that it’s a reflection, the brain will think that it’s looking at a stranger through a window. It shows up mostly in Alzheimers patients, but apparently even then, it’s rare.

I read about experiments where the scientist would present the person with a mirror, and then hold an object behind them. A normal person would look behind and grab the object, but an affected person would attempt to grab the object through the mirror. That is crazy..

Anyway, those are the ones that most interested me. Thanks Tortora.

Hope it was informative!



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