The brain is a remarkable organ, always undergoing changes. For example, studies show the brain shrinks as we age, particularly in the frontal cortex. In fact, our brains are changing every minute of the day, from our time in the womb until the moment we die.
We also know there are certain times in our lives during which the brain is most malleable.
During our teen years, our brains are ripe with opportunity for learning and growth. As we approach adolescence, the prefrontal cortex — the executive control center — is busy maturing, with a significant spurt of growth just before puberty. But the most significant change taking place in the adolescent brain is not growth in brain regions but an increase in communications among groups of neurons.
Research suggests baby brains start laying down the groundwork of how to form words long before they actually begin to speak. Infants can tell the difference between sounds of all languages until about eight months of age after which their brains start to focus only on the sounds they hear around them.
Researchers have also long understood that certain regions of adult brain's visual cortex respond to specific types of input — such as faces, objects, bodies and natural scenes — but the origins of these responses have been the topic of debate.
Comparing the brains of infants with the brains of adults could help answer such questions, except that neuroimaging the brains of babies who are awake and have limited tolerance has proven difficult. In a recent study, neuroscientists at MIT adapted their MRI, using a number of technical advances to increase infants' comfort, optimize signal strength and minimize head motion artifacts.
In their study, neuroscientists obtained low-motion MRI data from nine infants (of 17 tested; age 3-8 months) as they viewed engaging, brightly colored, infant-friendly movies of faces, natural scenes, scrambled scenes, human bodies and objects. From 26 hours of scanning, the researchers obtained four hours of usable data.
In adults, certain brain regions prefer to look at faces and socially relevant things while other brain regions prefer to look at environments and objects, and study results revealed that many regions of the babies' visual cortex showed the same preferences. This suggests such preferences form within the first few months of life rather than previous hypotheses suggesting it takes years of experience interpreting the world for the brain to develop such responses.
This study revealed that the cortex of 4- to 6-month-old babies is already spatially organized with distinct regions responding preferentially to human faces versus natural scenes. The spatial structure of these responses is similar to that observed in adults, extending throughout the cortex, including occipital, temporal, parietal and frontal regions.
The researchers, including Rebecca Saxe, a professor of brain and cognitive sciences and member of MIT's McGovern Institute for Brain Research, are planning to scan more babies between the ages of 3 and 8 months to help ascertain how vision-processing regions change over the first several months of life as well as younger babies to ascertain just when these brain responses first appear.
