The corpus callosum is a wide, flat bundle of neural fibers beneath the cortex in the eutherian brain at the longitudinal fissure. It connects the left and right cerebral hemispheres and facilitates inter- hemispheric communication. It is the largest white matter structure in the brain, consisting of 200–250 million contra lateral-axonal projections.
Agenesis of the corpus callosum (AgCC)
Agenesis of the corpus callosum (AgCC) is a rare birth defect (congenital disorder) in which there is a complete or partial absence of the corpus callosum. It occurs when the corpus callosum fails to develop normally, typically during pregnancy. The development of the fibers which would otherwise form the corpus callosum become longitudinally oriented within each hemisphere and form structures called probst bundles.
Initial symptoms of ACC usually include seizures, which may be followed by feeding problems and delays in holding the head erect, sitting, standing, and walking. Other possible symptoms may include impairments in mental and physical development, hand-eye coordination, and visual and auditory memory.
People born with AgCC still show normal communication between two halves of the brains 
Neuroscientists at the California Institute of Technology (Caltech) have found that people who are born with AgCC, still show remarkably normal communication across the gap between the two halves of their brains. Their findings are published in a paper in the October’19 in The Journal of Neuroscience.
According to J. Michael Tyszka, lead author of the paper and Associate Director of the Caltech Brain Imaging Center, many areas of the brain display slowly varying patterns of activity that are similar to one another. The fact that these areas are synchronized is probably due to presence of interconnected network called a resting-state network. Much to...
their surprise, Tyszka and his team found that these resting-state networks look essentially normal in people with AgCC, despite the lack of connectivity.
Tyszka observed “This was a real surprise. We expected to see a lot less coupling between the left and right brain in this group – after all, they are missing about 200 million connections that would normally be there. How do they manage to have normal communication between the left and right sides of the brain without the corpus callosum?”
The researchers used functional magnetic resonance imaging ( fMRI) to demonstrate that synchronized activity between the left and right brain survives even this sort of radical rewiring of the nerve connections between the two hemispheres. The presence of symmetric patterns of activity in individuals born without a corpus callosum shows the brain’s remarkable plasticity and ability to compensate.
About a third of people with AgCC also have autism, and altered connectivity in the corpus callosum has been found in autism. The remarkable compensation in brain functional networks found may thus have important implications also for understanding the function of the brains of people with autism.
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Tammie,I understand where you are comnig from although my story is different. We were given our perfect little baby that scored 9.5 on the scale used in the hospital over 29 years ago only to find that he kept missing all those milestones. He walked late, was totally non-verbal and he didn’t smile for at least the first eight months. After insisting that something was wrong the doctor agreed to blood tests which showed an irregular chromosome pattern and Trisomy-21 was his diagnosis. A form of Downs Syndrome.Whereas your world came crashing down at birth, mine did at my son’s age of 4. I understand your struggles and ours are still one day at a time. Neal does many things that I am sure you would be happy to have your son accomplish. Neal can drive (he drives me crazy most of the time), Neal is stubborn, determined, and has the ability to write and read. He is limited in his higher thinking skills, such a managing money and saving. When he was diagnosed there was limited information available on the outcome of his condition. All we knew was that he was ours, a gift from God, a child that had been sugar-coated, had gained our love, and was given into our care. We opted to homeschool him and his four other siblings. And, life has continued.If I can share any thoughts they are that life continues. I did go through one year of mourning the situation. For him, for ourselves and for our family. The what ifs and what could have been kept a constant refrain in my mind. What I will say is once those thoughts were squelched (holding every thought captive), I was able to see with clarity. We paid for speech therapy, occupational therapy and many other therapies that cost thousands upon thousands of dollars. Did any of these things work ? It is debatable. What I do know is that prayer and a love of the Lord has been strengthened and fortified by having this child. Neal loves the Lord. What else could I ask? I look forward to reading your blog and hearing from others with children who are indeed special as every child IS a gift from God.