We have discussed the way nerves communicate and how they decide when they are going to send impulses to other nerve cells. We know that groups of nerves collect information and fire together in pathways that stimulate distant parts of the brain. We also know that it is essential for different areas of the brain to communicate well with each other for us to be able to do the amazing complicated things we do with our brains.
The brain is divided into the left and right hemispheres. In these hemispheres the vast array of jobs that must be done are divided up and organized. Each hemisphere is also separated into special sections or lobes. These are the frontal, parietal, temporal and occipital lobes. The parietal lobe is mostly concerned with sensation of the body and locating where things happen. There is a map of the opposite side of the body inside each parietal lobe. So the left parietal lobe of the brain feels everything on the right side of the body and vice versa. The same type of thing happens for the occipital lobes sensing vision, the temporal lobes sensing hearing and the frontal lobes controlling muscle movements on the opposite side of the body. The frontal lobe is also what we call the executive center because it is responsible for making decisions and carrying out actions.
Now, imagine you are in a toy store. A train on its track is making its way around the store chugging and whistling. You turn your head to see where it is. As it comes into view you see an egg on one of the cars and you want to pick it up. It sounds like a simple thing but when you really think about it, it involves the whole brain and is quite complex. First, the ears are stimulated, changing the sound vibrations in the air to electrical impulses traveling along nerves. The impulses are sent to the temporal lobe so we can know what we are hearing and to the parietal lobe so we can know from where we are hearing it. The temporal lobes compare all the different frequencies in the sounds and their relative volumes and figure out what that whistling sound is. At the same time both parietal lobes take information from the ears and compare between the two sides which one hears the sound louder and if the volumes are changing to figure out where the sound is coming from.
The temporal and parietal lobes then send their perceptions forward to the frontal lobe so it can decide what they are, what they are doing, whether the sounds are dangerous or not and what to do about it. The frontal lobe then fires the muscles in the neck and moves the muscles in the eyes in perfect sequence to pinpoint the position of the toy train and then track its trajectory. In order to do this, it needs the occipital lobe which is now receiving visual stimulation from the eyes and forwarding it to the frontal lobe. The sound from each ear, the sight from both eyes, and the position sense in all the muscles involved must be synchronized by an internal timer so that differences in lengths of nerves and processing times do not confuse the frontal lobe like watching a movie where the sound is delayed so you see the lips moving but the words do not make sense. I have not even started to talk about what it's going to take to judge the speed of this train, time the movement of the arm, sequence the firing of the muscles in the arm and hand, and judge and re-judge the pressure on the egg so we do not break it.
Without communication, timing and sequencing within the brain we simply can not operate smoothly in the world. As we know many of our children are experiencing functional disconnections of these different parts of their brains that we may have previously described as "sensory integration problems", clumsiness, poor eye contact, unusually high pain threshold, difficulty following directions or so many other things . The Listening Program, the Integrative Metronome, the other therapies we do in our office and the exercises we have patients do at home are intended to connect or reconnect the different areas of the brain in the proper sequence so our kids can perform the majestic complexity that we all take for granted.