Nerve clusters may hold clues to facial blindness

What started out as a routine medical observation for epilepsy has turned into a unique scientific discovery concerning the brain’s ability to perceive.  After performing small experiments on a patient with electrodes temporarily implanted in his brain, Stanford researchers have pinpointed two nerve clusters that play a crucial role in the brain’s ability to distinguish one face from another.

The discovery could shed light on how to treat prosopagnosia, or “facial blindness,” a condition in which a person is unable to recognize individual faces.  The nerve clusters – called the fusiform gyrus – could also help explain why some people are better at recognizing faces than others.

The research all started when Ron Blackwell, 47, went to the hospital to get his epilepsy under control.  Since having his first seizure at 11-years-old, Blackwell has struggled with epilepsy for most of his life.  He experimented with different medications and was able to get his seizures under control – until they recently started back up again.

“Three years ago I started to have more frequent seizures, to the point where it was once month,” Blackwell told  “One day, I had eight seizures back to back.  That was a long day.”

Blackwell, of Santa Clara, Calif., sought help from Dr. Josef Parvizi, an associate professor of neurology and neurological sciences at the Stanford School of Medicine.   Parvizi became very interested in Blackwell’s case, due to his bizarre description of his seizures.

According to Blackwell, whenever one of his seizures would begin, he would see various colors in front of his eyes, as well as a series of memories and images.

“It would be the same sequence of memories with each seizure, which was just very bizarre,” Blackwell said.  “It was familiar images of people, a sequence of images of building blocks of A, B and C. I remember seeing McDonald’s arches.  It would always be the same sequence that I’d go through each time.”

Parvizi recommended Blackwell to come into the hospital for observation so that they could localize the seizures.  Epilepsy typically occurs when a small spot in the brain – called the focus – short circuits and sends electrical activity through the brain. The focus can vary from patient to patient, so observation is often needed to locate the seizure source and then dissect it.  Doctors also need to determine if the focus is located near any vital brain structures so that they do not remove areas that are extremely important.

During Blackwell’s observation, the electrodes had been planted in a very specific place in the brain, which included the fusiform gyrus – ultimately leading to the surprising discovery.

“[Neurosurgeons] had put the electrodes in the area of the brain that are important for vision, because Ron’s auras had visual characters,” Parvizi told  “…When we do functional mapping, we send electricity through the electrodes I implanted.  It doesn’t damage the brain, but it kind of tickles and perturbs it.”

Parvizi would target certain areas of the brain, press a button sending small amounts of electricity, and ask Blackwell what he would see.  Initially, Blackwell saw the bizarre colors, indicating that Parvizi had tapped into his seizure source.  But then, Blackwell saw something even more unique.

“Then he said, ‘Now what do you see?’ And that’s when his face changed,” Blackwell said. “It was like an instantaneous change.  His eyes and nose dropped about two inches down and to his right. Then he let his finger off the button and his face returned to normal.  We tried it on his assistant, and her face became disfigured too.  It was just amazing.”

Not only did the faces become disfigured, but Blackwell said they looked almost animated.  He noted that everything else stayed the same – his hair color, his height and his glasses even stayed on – yet his face was nearly unrecognizable.  Blackwell said he was blown away.

He wasn’t the only one shocked by the facial change.  Parvizi did not expect anything like that to happen.

“Whenever [Blackwell] told me about the face metamorphosis, I was taken by surprise,” Parvizi said, noting his genuine look of surprise was recorded in the research video.  “Something like this has never been recorded in the literature.”

The two nerve clusters Parvizi targeted of the fusiform gyrus, pFus and mFus, have long been suspected to be involved in facial recognition and perception.  The structure is about the shape of a hand-rolled cigarette, located under the temporal lobe.

The discovery could potentially lead to treatment for those with facial blindness, or prosopagnosia, which is a pathological condition.  But most importantly, the Stanford experiment is the first to show a cause-and-effect relationship between the fusiform gyrus and facial perception.

“Now we have established these two regions to be causally involved in perceiving faces,” Parvizi said.  “Why do we have specialized regions for recognizing faces? You need to have specialized neurons that can detect extreme subtitles in the shape or features of faces.  If you look at all faces, they’re pretty similar – only the subtitles make differences between one face and the other.  Recognizing features of faces has been evolutionarily extremely important, so that’s why these areas of have evolved to help us with this.  These areas are the core of social way of life.”

As for Blackwell, while the scientists were able to pinpoint his epilepsy’s focus, the source was too close to other key parts of the brain – so they did not operate.  However, he’s been on a new medication, and his seizures have significantly subsided.  Because he has two daughters and wife, he wanted to be seizure-free for them – and he’s happy to have helped with a major scientific discovery along the way.

“It was really for my girls,” Blackwell said. “I wanted to be able to take them to the park and not have a seizure.  I wanted them to feel completely safe and I do now. I feel great.”