A rather curious experiment with an extremely trippy outcome has been described in the Proceedings of the National Academy of Sciences. Namely, a man with 188 metallic patches in his brain starting seeing faces everywhere he looked when they were electrified.
The man in question was a patient who was being treated for epilepsy. As part of this somewhat experimental treatment, he had electrode strips implanted along his fusiform gyri, regions of the brain thought to play a key role in pattern and visual recognition.
A team from the National Center for Adaptive Neurotechnologies at the New York State Department of Health saw an opportunity here. This part of the human brain is particularly difficult to study, and most of the work that has been done has involved other primates. This 26-year-old man represented a chance to directly probe this elusive cranial segment.
Previous work has demonstrated that disrupting the electrical connections in this part of the brain – the fusiform face area (FFA) – reduces a person’s ability to see faces properly. The various individual shapes don’t come together as a cohesive whole. What would happen if these signals were amplified through electrical stimulation?
The team wondered just that, and asked their subject to look at a variety of objects – including a football, a box, and a person’s face – while they sent electrical pulses into the FFA. Remarkably, he began to see ephemeral illusory faces all over the place, including within the real face of a person.
It’s safe to say that this left him a little bemused. “Your face changed completely,” he said, staring at one of the researchers. “I don’t know what’s going on. Your eyes…change.” Often, the faces – which faded from view quickly – looked a lot like a “cartoon character,” or even, quite specifically, an “anime character.”
These hallucinations are referred to as facephenes by the team, who point out that such a phenomenon has not be recognized before.
That’s not all. The stimulation of sites in the FFA known to be associated with color caused ghostly rainbows to suddenly appear on various faces and objects. In both cases, the objects didn’t seem to change themselves; the facephenes and rainbows seemed to linger on them, as if they’d been superimposed by a projector.
This bizarre study’s findings suggest that the FFA is a vital part of the brain that processes very specific information about colors and faces. As pointed out by Neuroskeptic, however, an early study investigating the same thing didn’t seem to provoke the appearance of any transient cartoon characters – so perhaps only certain people see facephenes.