Navigation Links
Difficulty in recognizing faces in autism linked to performance in a group of neurons
Date:3/18/2013

WASHINGTON Neuroscientists at Georgetown University Medical Center (GUMC) have discovered a brain anomaly that explains why some people diagnosed with autism cannot easily recognize faces a deficit linked to the impairments in social interactions considered to be the hallmark of the disorder.

They also say that the novel neuroimaging analysis technique they developed to arrive at this finding is likely to help link behavioral deficits to differences at the neural level in a range of neurological disorders.

The final manuscript published March 15 in the online journal NeuroImage: Clinical, the scientists say that in the brains of many individuals with autism, neurons in the brain area that processes faces (the fusiform face area, or FFA) are too broadly "tuned" to finely discriminate between facial features of different people. They made this discovery using a form of functional magnetic resonance imaging (fMRI) that scans output from the blueberry-sized FFA, located behind the right ear.

"When your brain is processing faces, you want neurons to respond selectively so that each is picking up a different aspect of individual faces. The neurons need to be finely tuned to understand what is dissimilar from one face to another," says the study's senior investigator, Maximilian Riesenhuber, PhD., an associate professor of neuroscience at GUMC.

"What we found in our 15 adult participants with autism is that in those with more severe behavioral deficits, the neurons are more broadly tuned, so that one face looks more like another, as compared with the fine tuning seen in the FFA of typical adults," he says.

"And we found evidence that reduced selectivity in FFA neurons corresponded to greater behavioral deficits in everyday face recognition in our participants. This makes sense. If your neurons cannot tell different faces apart, it makes it more difficult to tell who is talking to you or understand the facial expressions that are conveyed, which limits social interaction."

Riesenhuber adds that there is huge variation in the ability of individuals diagnosed with autism to discriminate faces, and that some autistic people have no problem with facial recognition.

"But for those that do have this challenge, it can have substantial ramifications some researchers believe deficits in face processing are at the root of social dysfunction in autism," he says.

The neural basis for face processing

Neuroscientists have used traditional fMRI studies in the past to probe the neural bases of behavioral differences in people with autism, but these studies have produced conflicting results, says Riesenhuber. "The fundamental problem with traditional fMRI techniques is that they can tell which parts of the brain become active during face processing, but they are poor at directly measuring neuronal selectivity," he says, "and it is this neuronal selectivity that predicts face processing performance, as shown in our previous studies."

To test their hypothesis that differences in neuronal selectivity in the FFA are foundational to differences in face processing abilities in autism, Riesenhuber and the study's lead author, neuroscientist Xiong Jiang, PhD, developed a novel brain imaging analysis technique, termed local regional heterogeneity, to estimate neuronal selectivity.

"Local regional heterogeneity, or Hcorr, as we called it, is based on the idea that neurons that have similar selectivities will on average show similar responses, whereas neurons that like different stimuli will respond differently," says Jiang. "This means that individuals with face processing deficits should show more homogeneous activity in their FFA than individuals with more typical face recognition abilities."

They tested the method in 15 adults with autism and 15 adults without the disorder. The autistic participants also underwent a standard assessment of social/behavioral functioning.

The researchers found that in each autistic participant, behavioral ability to tell faces apart was tightly linked to levels of tuning specificity in the right FFA as estimated with Hcorr. This finding was confirmed by another advanced imaging technique, fMRI rapid adaptation, shown by the group in previous work to be a good estimator of neuronal selectivity.

"Compared to the more well-established fMRI-rapid adaptation technique, Hcorr has several significant advantages," says Jiang. "Hcorr is more sensitive and can estimate neuronal selectivity as well as fMRI rapid adaptation, but with much shorter scans, and Hcorr can even estimate neuronal selectivity using data from resting state scans, thus making the technique suitable even for individuals that cannot perform complicated tasks in the scanner, such as low-functioning autistic adults, or young children."

"The study suggests that, just as in typical adults, the FFA remains the key region responsible for face processing and that changes in neuronal selectivity in this area are foundational to the variability in face processing abilities found in autism. Our study identifies a clear target for intervention," says Riesenhuber. Indeed, after the study was completed, the researchers successfully attempted to improve facial recognition skills in an autistic participant. They showed the participant pairs of faces that were very dissimilar at first, but became increasingly similar, and found that FFA tuning improved along with behavioral ability to tell the faces apart. "This suggests high-level brain areas may still be somewhat plastic in adulthood," says Riesenhuber.


'/>"/>

Contact: Karen Mallet
km463@georgetown.edu
Georgetown University Medical Center
Source:Eurekalert

Related medicine news :

1. Study finds people have difficulty controlling multiple chronic conditions
2. Food elimination diet identifies causes of difficulty swallowing and swelling of the throat
3. Why do age-related macular degeneration patients have trouble recognizing faces?
4. Implicit race bias increases the differences in the neural representations of black and white faces
5. Home Sales 19 Consecutive Monthly Gain Faces 2013 Wild Cards
6. Scientists Spot 5 Genes That Help Shape Faces
7. UCLA study to determine if copper surfaces can reduce hospital-acquired infections
8. Scientists uncover multiple faces of deadly breast cancer
9. Autism Speaks trailblazer study -- Blocking cell distress signals can ease autism symptoms
10. Bradley Hospital researchers find age-related changes in how autism affects the brain
11. Trump Steps Up to Support Els for Autism
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/26/2016)... (PRWEB) , ... June 26, 2016 , ... On June ... sponsor of the 2016 Cereal Festival and World’s Longest Breakfast Table in Battle Creek, ... of the city’s history as home to some of the world’s leading providers of ...
(Date:6/25/2016)... D.C. (PRWEB) , ... June 25, 2016 , ... ... discuss health policy issues and applications at AcademyHealth’s Annual Research Meeting June 26-28, ... their work on several important health care topics including advance care planning, healthcare ...
(Date:6/25/2016)... , ... June 25, 2016 , ... As a lifelong ... Cum Laude and his M.D from the David Geffen School of Medicine at UCLA. ... to Los Angeles to complete his fellowship in hematology/oncology at the UCLA-Olive View-Cedars Sinai ...
(Date:6/24/2016)... ... June 24, 2016 , ... Those who have experienced traumatic events may suffer ... unhealthy avenues, such as drug or alcohol abuse, as a coping mechanism. To avoid ... healthy coping following a traumatic event. , Trauma sufferers tend to feel a range ...
(Date:6/24/2016)... San Francisco, CA (PRWEB) , ... June 24, ... ... at CitiDent, is now offering micro-osteoperforation for accelerated orthodontic treatment. Dr. Cheng has ... , self-ligating Damon brackets , AcceleDent, and accelerated osteogenic orthodontics. , ...
Breaking Medicine News(10 mins):
(Date:6/23/2016)... , June 23, 2016 Research ... Devices Global Market - Forecast to 2022" report to ... the treatment method for the patients with kidney failure, it ... excess fluid from the patient,s blood and thus the treatment ... potassium and chloride in balance. Increasing number ...
(Date:6/23/2016)... Roche (SIX: RO, ROG; OTCQX: RHHBY) announced ... BRAHMS PCT (procalcitonin) assay as a dedicated testing solution ... this clearance, Roche is the first IVD company in ... sepsis risk assessment and management. PCT is ... levels in blood can aid clinicians in assessing the ...
(Date:6/23/2016)... , June 23, 2016 Bracket , a ... its next generation clinical outcomes platform, Bracket eCOA (SM) ... on June 26 – 30, 2016 in Philadelphia ... electronic Clinical Outcome Assessment product of its kind to fully ... Bracket eCOA 6.0 is a flexible platform for ...
Breaking Medicine Technology: