When beginning to think about the workings and science behind how the human brain takes in what is in their environment and how they act on that stimuli, people often overlook the very intricate and key component of brain responses in one’s social awareness and expression. Everyone is quick to jump on the learning train of how humans respond to media, academics, and work. Let’s look over how the human brain responds to the faces and facial expressions of others. Much research in neuroscience and psychology focuses on adult brains, looking at infant's brains is also crucial in order to understand where these adults are coming from. Understanding where it all began and see how much the brain has changed in ability from infancy allows scientists a more in depth and well rounded understanding of the human brain.
Infants in general are sensitive to everything around them. They are at a stage in life where they are being introduced to thousands of stimuli unexpectedly every day and have to learn how to react to them. Studies have already been done that look at how an infants’ brain responds to stimuli based on closely observing the amplitudes of ERP responses of the brain to stimuli. This exact study, “Face Sensitive Responses Brain Responses In The First Year of Life,” done by Stefania Conte and others tell us which brain areas are working together when they are exposed to stimuli and at what rate they are working.
The anatomy and research behind how the human brain is very captivating and eye opening. These groundbreaking findings in infant responses help the medical and scientific community better understand how the brain works and why it works the way it does base on observing results on how the brain responds in its first stages of use and exposure to the world in which it is in.
In a research article, “Brain Responses to Faces and Facial Expressions in 5-Month-Olds: An fNIRS Study,” researchers, Renata Di Lorenzo and others, explore infant brain activity and processing in response to different emotional facial expressions. Building on what was said before, understanding and recognizing facial expressions and faces are very important for humans especially when looking at social psychology and communication. The networks in the brain that work together in processing facial expressions have been explored in adults, but little to none has been researched in infants. The researchers study this by using functional near-infrared spectroscopy (fNIRS) to measure brain activity when the baby is exposed to the stimuli. The fNIRS is a non-invasive tool that researchers placed on the baby’s head. This method was chosen because of the tool’s ability to measure encoding and retrieval activity in the brain by showing researchers brain activation based on the emission of light and changes in HbO2 levels in certain areas of the brain. With the fNIRS, three areas of the brain will be observed: frontal, temporal, and occipital cortices. Researchers hope to find which area of the brain is used in facial emotion processing.
As noted by the researchers, facial and expression identification in infants isn’t as mature as older ages. Infants have shown that they are more drawn to faces than non-face objects and stimuli. This may be possible given how close infants are to their parents when they are born. The brain’s ability to categorize emotions and expressions matures faster than the processing of just faces.
The researchers studied a panel of 17, 5-month-old infants. There were nine girls and 8 boys. For the stimuli, six older females were selected and they showed facial expressions of happiness and fear. Researchers then looked at how the infant’s brain’s processing and activity when seeing faces and emotions from the six older females. Specifically, researchers wanted to see in which cortical regions there was more activity.
The results show several key findings. First, there is dominance in activity of the right hemisphere of the brain over the left. Second, amongst the cortical areas, it is the occipital area that experiences the most activity and heightened processing of faces. However, it's processing of faces is without the processing of facial emotional expressions. This contradicts the idea presented before, in that here, that the brain’s processing network of faces is more active and mature than the processing of emotions. However, the idea previously stated was looking at babies processing at 7 months compared to this study which is 5 months. So it is safe to say to some degree, that the processing of both faces and emotions mature together in time. The conclusion was reached by looking at increased markings of levels of HbO2 brain activity in the occipital lobe when exposed to faces.
Very similar to a study done by Stefania Conte and others, as mentioned above, face stimuli were better recognized by babies in their first year of life compared to objects. The heightened activity in her study was shown in the middle/posterior fusiform gyri which is also in the right hemisphere just like in the study done by Renata Di Lorenzo.
These findings are new breakthroughs in the scientific community in understanding more in depth the processing and activity of the brain in infants. However, it can’t stop there. More research should definitely be done as there is always more to learn and uncover. There are some things to note that could be different in future trials. First, they can use more infants being tested to better certify their results. With more babies, they should also look to test infants at different ages in months to see the steady developmental growth in brain capabilities. Looking at infants in later months than five would probably allow researchers to see a more mature emotion processing network to be compared to the face processing network that was found in this study. Also, as found by the researchers, there was a right hemisphere dominance in this study. Researchers should look more into potential findings and breakthroughs in activity and processing in the left hemisphere and find connections between both left and right hemispheres. While there's still a long road ahead to further unmap more the brain's neural workings and processing, these results signify a leap in knowledge about the brain’s activity in response to faces and emotions in infants that was never known before.
Conte, Stefania., et al. “Face Sensitive Responses Brain Responses In The First Year of Life.” NeuroImage, Elsevier. 8 Feb. 2020.
https://www.sciencedirect.com/science/article/pii/S1053811920300896?via%3Dihub
Di Lorenzo, Renata., et al. “Brain Responses to Faces and Facial Expressions in 5-Month-Olds: An fNIRS Study.” Frontiers, Frontiers. 15 Nov. 2019.
https://www.frontiersin.org/articles/10.3389/fpsyg.2019.01240/full
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