Identifying the brain's own facial recognition system

 

Palo Alto, California

The ability to recognize faces is so important in humans that the brain appears to have an area solely devoted to the task: the fusiform gyrus.

Brain imaging studies consistently find that this region of the temporal lobe becomes active when people look at faces. Skeptics have countered, however, that these studies show only a correlation, but not proof, that activity in this area is essential for face recognition. Now, thanks to the willingness of an intrepid patient, a new study provides the first cause-and-effect evidence that neurons in this area help humans recognize faces-and only faces, not other body parts or objects.

An unusual collaboration between researchers and an epilepsy patient led to the discovery. Ron Blackwell, an engineer in Santa Clara, California, came to Stanford University in Palo Alto, California, in 2011 seeking better treatment for his epilepsy. He had suffered seizures since he was a teenager, and at age 47, his medication was becoming less effective. Stanford neurologist Josef Parvizi suggested some tests to locate the source of the seizures-and also suggested that it might be possible to eliminate the seizures by surgically destroying a tiny area of brain tissue where they occurred.

Parvizi used electrodes placed on Blackwell's scalp to trace the seizures to the temporal lobe, about an inch above Blackwell's right ear. Then, surgeons placed more electrodes on the surface of Blackwell's brain, near the suspect point of origin in the temporal lobe. Parvizi stimulated each electrode in turn with a mild current, trying to trigger Blackwell's seizure symptoms under safe conditions. "If we get those symptoms, we know that we are tickling the seizure node," he explains.

Certain electrodes, however, produced a dramatically different result from the colors and memories that Blackwell typically experienced. When Parvizi sent a signal through these electrodes on the fusiform gyrus, Blackwell told him, "You just turned into somebody else. Your whole face just sort of metamorphosed." When the stimulation was halted, Blackwell reported that Parvizi's face had "returned" to normal. The same test caused Blackwell to perceive unsettling distortion in the face of Parvizi's assistant.

But the electrode stimulation affected only Blackwell's perception of faces of people he could see in person. Stimulating the two points also produced no change in Parvizi's suit, tie, or skin color, or in other objects around the room.

While the electrodes were in place, Parvizi got Blackwell's permission to turn the clinical probe into a research study, described online tomorrow in The Journal of Neuroscience. Teaming up with Stanford neuroscientist Kalanit Grill-Spector, who studies the brain areas important in facial recognition, he scanned Blackwell's brain using functional magnetic resonance imaging (fMRI) and confirmed that the two electrodes that influenced Blackwell's perception of faces were at points in the fusiform gyrus implicated by Grill-Spector's previous research. The researchers also recorded brain activity using the electrodes they'd placed on Blackwell's brain with a technique called electrocorticography. They found that the activity picked up by the electrodes at the two "hot spots" tracked with peak activity at these sites, as measured by fMRI.

Cognitive neuroscientist Juan R. Vidal of the Lyon Neuroscience Research Center in France applauds the authors' use of multiple methods and says the study is the first to prove that the fusiform gyrus plays a causal role in face perception. Previous studies only showed that the area is involved, Vidal says. "The complementary evidence of electrocorticography, fMRI, and brain stimulation will make it possible to study not only the effects of brain stimulation on the local neural networks that process face information, but also how they broadcast their information towards other regions in the brain."

- - -

This is adapted from ScienceNOW, the online daily news service of the journal Science. http://news.sciencemag.org

News
Russell Brand was in typically combative form during his promotional interview with Newsnight's Evan Davis
peopleReports that Brand could stand for Mayor on an 'anti-politics' ticket
News
The clocks go forward an hour at 1am on Sunday 30 March
news
Arts and Entertainment
The Doctor finds himself in a forest version of London in Doctor Who episode 'In the Forest of the Night'
TVReview: Is the Doctor ever going stop frowning? Apparently not.
News
Voluminous silk drawers were worn by Queen Victoria
newsThe silk underwear is part of a growing trade in celebrity smalls
PROMOTED VIDEO
Sport
footballMatch report: Real fight back to ruin Argentinian's debut
News
Candidates with surnames that start with an A have an electoral advantage
newsVoters are biased towards names with letters near start of alphabet
Arts and Entertainment
Isis with Lord Grantham (Hugh Bonneville)
TV
Arts and Entertainment
Jay James
TVReview: Performances were stale and cheesier than a chunk of Blue Stilton left out for a month
News
ebooksAn unforgettable anthology of contemporary reportage
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Maths Teacher

£110 - £200 per day: Randstad Education Leeds: Secondary Maths Teacher for spe...

Business Analyst - Surrey - Permanent - Up to £50k DOE

£40000 - £50000 Per Annum Excellent benefits: Clearwater People Solutions Ltd:...

***ASP.NET Developer - Cheshire - £35k - Permanent***

£30000 - £35000 Per Annum Excellent benefits: Clearwater People Solutions Ltd:...

***Solutions Architect*** - Brighton - £40k - Permanent

£35000 - £40000 Per Annum Excellent benefits: Clearwater People Solutions Ltd:...

Day In a Page

Wilko Johnson, now the bad news: musician splits with manager after police investigate assault claims

Wilko Johnson, now the bad news

Former Dr Feelgood splits with manager after police investigate assault claims
Mark Udall: The Democrat Senator with a fight on his hands ahead of the US midterm elections

Mark Udall: The Democrat Senator with a fight on his hands

The Senator for Colorado is for gay rights, for abortion rights – and in the Republicans’ sights as they threaten to take control of the Senate next month
New discoveries show more contact between far-flung prehistoric humans than had been thought

New discoveries show more contact between far-flung prehistoric humans than had been thought

Evidence found of contact between Easter Islanders and South America
Cerys Matthews reveals how her uncle taped 150 interviews for a biography of Dylan Thomas

Cerys Matthews on Dylan Thomas

The singer reveals how her uncle taped 150 interviews for a biography of the famous Welsh poet
DIY is not fun and we've finally realised this as a nation

Homebase closures: 'DIY is not fun'

Homebase has announced the closure of one in four of its stores. Nick Harding, who never did know his awl from his elbow, is glad to see the back of DIY
The Battle of the Five Armies: Air New Zealand releases new Hobbit-inspired in-flight video

Air New Zealand's wizard in-flight video

The airline has released a new Hobbit-inspired clip dubbed "The most epic safety video ever made"
Pumpkin spice is the flavour of the month - but can you stomach the sweetness?

Pumpkin spice is the flavour of the month

The combination of cinnamon, clove, nutmeg (and no actual pumpkin), now flavours everything from lattes to cream cheese in the US
11 best sonic skincare brushes

11 best sonic skincare brushes

Forget the flannel - take skincare to the next level by using your favourite cleanser with a sonic facial brush
Paul Scholes column: I'm not worried about Manchester United's defence - Chelsea test can be the making of Phil Jones and Marcos Rojo

Paul Scholes column

I'm not worried about Manchester United's defence - Chelsea test can be the making of Jones and Rojo
Frank Warren: Boxing has its problems but in all my time I've never seen a crooked fight

Frank Warren: Boxing has its problems but in all my time I've never seen a crooked fight

While other sports are stalked by corruption, we are an easy target for the critics
Jamie Roberts exclusive interview: 'I'm a man of my word – I'll stay in Paris'

Jamie Roberts: 'I'm a man of my word – I'll stay in Paris'

Wales centre says he’s not coming home but is looking to establish himself at Racing Métro
How could three tourists have been battered within an inch of their lives by a burglar in a plush London hotel?

A crime that reveals London's dark heart

How could three tourists have been battered within an inch of their lives by a burglar in a plush London hotel?