Scientists Discover A New Class Of Neurons For Remembering Faces
An area in the brains temporal pole specializes in familiar face recognition.
Scientists have long searched in vain for a class of brain cells that could explain the visceral flash of recognition that we feel when we see a very familiar face, like that of our grandmothers. But the proposed grandmother neurona single cell at the crossroads of sensory perception and memory, capable of prioritizing an important face over the rabbleremained elusive.
Now, new research reveals a class of neurons in the brains temporal pole region that links face perception to long-term memory. Its not quite the apocryphal grandmother neuronrather than a single cell, its a population of cells that collectively remembers grandmas face. The findings, published in Science, are the first to explain how brains inculcate the faces of loved ones.
When I was coming up in neuroscience, if you wanted to ridicule someones argument you would dismiss it as just another grandmother neurona hypothetical that could not exist, says Winrich Freiwald, head of Rockefellers Laboratory of Neural Systems.
Now, in an obscure and understudied corner of the brain, we have found the closest thing to a grandmother neuron: cells capable of linking face perception to memory.
Have I seen that face before?
A tapestry of grandmothers
Its a grandmother face area of the brain, Freiwald says.
This discovery could one day help us devise strategies to help them.
The Part Of Your Brain That Recognizes Faces Continues Growing Later In Life
That is, at least until you hit 30
Remembering faces is often like a game of Guess Who. And neuroscientists have long thought that the tissues that make up this region of the brain stops growing fairly early in life. But a recent discovery is challenging this idea, Andy Coghlan reports for New Scientist. The study, published in the journal Science, suggests that the part of the brain in charge of facial recognition actually continues to develop until around age 30.
But the change wasn’t an in increase in neurons, but rather an increase in connections between existing neurons, Jon Hamilton reports for NPR. “You can imagine a ten-foot by ten-foot garden, and it has some number of flowers in there,” Jesse Gomez, a Stanford University neuroscience researcher and lead study author tells Hamilton. “The number of flowers isn’t changing, but their stems and branches and leaves are getting more complex.”
For the study, Gomez and his colleagues ran a series of MRI scans on 22 children between the ages of five and 12 and compared them to brain scans taken of 25 adults between ages 22 and 28. When they looked at the scans, a region at the base of the brain known as the fusiform gyrus stood out. The amount of brain tissue in the region became about 12.6 percent more dense, while the rest of the brain remained more or less the same, Ian Sample reports for The Guardian.
What Part Of The Brain Causes Prosopagnosia
The specific brain area usually associated with prosopagnosia is the fusiform gyrus, which activates specifically in response to faces. Acquired prosopagnosia results from occipito-temporal lobe damage and is most often found in adults.
Simply so, which part of the brain is responsible for facial recognition?
The temporal lobe of the brain is partly responsible for our ability to recognize faces. Some neurons in the temporal lobe respond to particular features of faces. Some people who suffer damage to the temporal lobe lose their ability to recognize and identify familiar faces. This disorder is called prosopagnosia.
Also, what is the cause of prosopagnosia? Prosopagnosia can be caused by stroke, injury to the brain, or some neurodegenerative diseases. In some cases, people are born with face blindness as a congenital disorder.
Subsequently, one may also ask, what part of the brain causes face blindness?
Prosopagnosia facts*Face blindness is thought to be the result of abnormalities, damage, or impairment in the right fusiform gyrus, a fold in the brain that appears to coordinate the neural systems that control facial perception and memory.
What is it called when you Cannot recognize faces?
Prosopagnosia is a neurological disorder characterized by the inability to recognize faces. Prosopagnosia is also known as face blindness or facial agnosia. Prosopagnosia can result from stroke, traumatic brain injury, or certain neurodegenerative diseases.
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Brain Activity And Face Recognition In Humans
Electrophysiological and magnetoencephalographic analyses have indicated that face processing might be monitored via several types of synchronized electrical activity in the brain. Specifically, theta and gamma oscillations appear to be helpful for distinguishing the recognition of known from unknown faces . Face perception induces gamma oscillations with a frequency higher than 30 Hz, reflecting the balance of GABA/glutamate-controlled inhibition/excitation in the brain. Such oscillations appear to be larger when a face is presented in comparison with other objects, and thus might be associated with the integration of visual inputs . In general, compared with object recognition, face recognition appears to activate more synchronized neuronal assemblies .
In young children with ASD, gamma oscillations recorded via EEG and MEG revealed signs of desynchronization . In terms of impaired brain functional connectivity in this population, the degree of developmental delay was found to correspond with the degree of excess gamma band oscillations in the frontal area, suggesting aberrant visual perception and cognition. Preserved visual reasoning ability was coupled with rightward lateralization in the functionally connected parietal and temporal regions in children with ASD . Face perception-induced activation can also be monitored via event-related potential components, particularly, the N170, which serves as a marker of face processing in the brain .
Neuroscientists Have Discovered The Closest Thing To The Infamous Grandmother Neuron They Have Identified The Cells Responsible For How The Brain Remembers Faces
Its not uncommon to hear the phrase Sorry, Im bad at faces in the middle of a conversation, when someone is asked to reintroduce themselves. You can be introduced to someone, then meet again without any defining memory of who youre talking to. On the opposite end of the spectrum, some people never forget a face smoothly identifying the person theyve seen just once.
But why? What makes some people remember?
Professor Winrich Freiwald, neurosciences and behaviour at The Rockefeller University, said: The expectation is that we would have had this down by now. Far from it! We had no clear knowledge of where and how the brain processes familiar faces.
A team at Rockefeller University have discovered, for the first time, what part of the human brain is responsible for recognising faces.
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Traumatic Brain Injury And Neurological Illness
Following brain damage, faces can appear severely distorted. A wide variety of distortions can occur — features can droop, enlarge, become discolored, or the entire face can appear to shift relative to the head. This condition is known as prosopometamorphopsia . In half of the reported cases, distortions are restricted to either the left or the right side of the face, and this form of PMO is called hemi-prosopometamorphopsia . Hemi-PMO often results from lesions to the splenium, which connects the right and left hemisphere. In the other half of reported cases, features on both sides of the face appear distorted.
Perceiving facial expressions can involve many areas of the brain, and damaging certain parts of the brain can cause specific impairments in one’s ability to perceive a face. As stated earlier, research on the impairments caused by brain injury or neurological illness has helped develop our understanding of cognitive processes. The study of prosopagnosia has been particularly helpful in understanding how normal face perception might work. Individuals with prosopagnosia may differ in their abilities to understand faces, and it has been the investigation of these differences which has suggested that several stage theories might be correct.
Difficulties in facial emotion processing can also be seen in individuals with traumatic brain injury, in both diffuse axonal injury and focal brain injury.
Coping With Face Blindness
Face blindness can impact someones ability to establish personal and professional relationships. This can lead to social anxiety or depression. Learning how to identify people in ways that dont rely on being able to recognize their face outright can help.
If you experience social anxiety or depression because of face blindness, consult a therapist. They can help you develop other techniques to:
- better connect with people
- manage your social anxiety or depression symptoms
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Oxytocin In Clinical Trials
A clinical trial study in which highly functioning individuals with ASD received a single intranasal dose of OT demonstrated that OT facilitated typical and smoother behavioral responses to social communication with conflicting verbal and non-verbal information . fMRI analyses have shown that the behavioral effects of oxytocin are associated with increased brain activity in the anterior cingulate cortex and dorsal medial prefrontal cortex , as well as improved functional connectivity from the dmPFC to the ACC . These observations are consistent with data from rodent studies showing that oxytocin signaling through OXTR in the medial prefrontal cortex is essential for cognitive flexibility .
Further, a 6-week intervention in highly functioning individuals with ASD significantly improved behavioral responses and increased functional connectivity between the ACC and dmPFC . Similarly, administration of a high dose of oxytocin during a 12-week period alleviated symptoms in male young adults with ASD, leading to an increased tendency to visually fixate on regions of social salience such as the eye region of the face, as well as improved biological motion . A study of long-term OT administration in male patients with ASD and comorbid intellectual disability found that, compared with a placebo, OT significantly increased the frequency of reciprocal social interactions in daily life during the period of administration .
New Study Reveals Areas Of Brain Where Recognition And Identification Occur
Using “sub-millimeter” brain implants, researchers at The University of Texas Health Science Center at Houston , have been able to determine which parts of the brain are linked to facial and scene recognition.
The study was published today in Current Biology.
“The ability to recognize familiar faces and locations is crucial to everyday life,” said Nitin Tandon, MD, lead author of the study and professor of neurosurgery at McGovern Medical School at UTHealth. “Identifying someone allows you to communicate with them and know who they are, and having this basic skill helps an individual attach an identity to those around them, making it easier to differentiate the who, what, and where.”
Traditionally, the hippocampus and parahippocampal gyri, located in the medial temporal lobe , are implicated as the main area for identification processes. However, recently it has become clear to researchers that the memory network responsible for identification extends beyond the MTL, including a region deep inside the brain called the medial parietal cortex .
During these tests, researchers would show patients around 300 photos of celebrity faces and famous landmarks to determine whether or not they could name what they were seeing.
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Human Behavior And Functional Imaging
The extensive behavioral literature on face perception provides a rich source of clues about the nature of the computations performed in processing faces. One of the hallmarks of face processing is that recognition performance drops substantially when faces are presented upside down or in negative contrast, and both effects are much smaller for objects . We propose that both these properties can be explained if only upright, positive-contrast faces gain access to the face processing system, i.e., if an upright, positive-contrast template is used for face detection. This template may be innate in humans, as evidenced by the tendency for newborns to track normal schematic faces longer than scrambled schematic faces .
Comparison Of Lesion To A Priori Face
Regions of interest were defined for the core face-selective regions from the Neurosynth face meta-analyses of task-functional MRI studies as was done for the a priori right FFA above . Bilateral FFA, occipital face areas , and amygdala regions were obtained as clusters of voxels with a Z > 10 using Nilearns connected_regions function to find contiguous regions containing at least 50 mm3 . Defining regions of interest for the bilateral superior temporal sulcus and the right inferior frontal gyrus required reducing the statistical threshold to Z > 4.5, corresponding to a false discovery rate corrected P-value of < 0.00001. To examine the relative sensitivity of the known face-selective regions for connectivity to lesions associated with acquired prosopagnosia, we used the lesion network mapping approach above to determine the proportion of lesions with a maximal T > ±9 within each a priori region of interest. We also calculated the pairwise average correlation between each a priori face-selective region of interest and each lesion in our prosopagnosia cohort and our two control cohorts. These correlation values were used to compute a two-way ANOVA for unequal group sizes using type III sum of squares with the car package in R to identify significant interaction effects. Post hoc one-way ANOVAs were also carried out, across group for each region of interest, to determine the relative specificity of lesion region of interest correlations across the three groups .
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Does My Child Have Prosopagnosia
It can be difficult to recognise prosopagnosia in children, but the following are potential signs:
- your child frequently fails to recognise familiar people when they meet them unexpectedly
- they’re particularly clingy in public places
- they wait for you to wave when you’re collecting them from school, or approach strangers thinking they’re you
- they’re socially withdrawn at school and have difficulty making friends
- they find it difficult to follow the plots of films or TV shows
The Centre for Face Processing Disorders has more information about prosopagnosia in children.
Page last reviewed: 01 May 2019 Next review due: 01 May 2022
Which Parts Of The Brain Are Involved
It will come as no surprise that a job as important and complicated as facial perception requires chatter between a variety of brain areas.
Face processing relies on a patchy network of regions in the temporal and frontal lobes. It also involves other parts of the brain that do not normally dabble in visual stimuli, such as the somatosensory cortex an area mostly concerned with receiving information about touch sensation.
The stimulation of the somatosensory cortex during the perception of facial expressions backs up the simulationist model. This model theorizes that, to understand the meaning behind a facial expression, individuals attempt to replicate the activity in their own brains.
The simulationist model is backed up by a few lines of research. For instance, patients who cannot themselves produce the facial expressions related to fear, disgust, or anger also find it difficult to recognize the same emotions in others.
Additionally, neuroimaging researchers have shown that similar brain regions are active when someone watches an emotional expression as when they attempt to imitate that same expression.
The amygdala also plays a part the almond-shaped subcortical structure is involved in memory, decision-making, and emotional reactions. If the amygdala is damaged, it can result in an inability to recognize fear in other people.
other types of recognition , too, it is clearly important in facial recognition.
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What Is The Fusiform Face Area And What Does It Do
By the late 1990s, researchers had built up a fair amount of evidence that suggested there are parts of our brain that are especially active when we look at faces. This research led neuroscientists to hypothesize that certain neurons are specialized to process information about faces, and that these neurons are essential to normal face perception. According to this view, the parts of the brain involved in face perception might be distinct from the parts of the brain involved in perceiving other things like objects.
In 1997, researchers published a groundbreaking study that not only supported the idea of face-specific processing in the brain, but also added some important anatomical detail. The study, by Nancy Kanwisher and colleagues, used functional magnetic resonance imaging to identify areas of the brain that were highly active when participants looked at faces. In the process, the researchers found a region about the size of a blueberry on the inferior surface of the temporal lobe that displayed a disproportionate amount of activity when participants viewed facesbut not when they viewed other things like houses, hands, or cars. In most patients, this activity was seen predominantly on the right side of the brain.
How Is Face Blindness Diagnosed
If youre having trouble recognizing faces, your primary care physician will refer you to a neurologist.
The neurologist may have you take an assessment that evaluates your ability to recognize facial features. The assessment may evaluate your ability to:
- recognize faces youve never seen, or faces of your family
- notice differences or similarities of facial features in sets of faces shown to you
- detect emotional cues from a set of faces
- assess information like age or gender from a set of faces
The Benton Facial Recognition Test and Warrington Recognition Memory of Faces are two tests that physicians may use to evaluate potential face blindness. The scores you get on these tests, however, may not be entirely reliable in diagnosing facial blindness outright. One study found that irregular scores were not actually consistent with face blindness. A physicians opinion is much more valuable.
There are also plenty of tests that claim to be able to diagnose face blindness online. Many of these are not accurate or valid, and youre better off consulting your physician if youre concerned.
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