How Genes Grow the Brain

Dr. Robert Melillo


At one time scientists believed that mental and physical growth were mutually exclusive, but this is not the case. One cannot exist without the other. Every biologically important event, from recognizing a mother’s touch or a father’s smile to sitting, crawling, walking and talking are dependent upon electrical communication in the brain. 

Though genes are responsible for building the brain, they are, for the most part, dependent on environmental influences to stimulate it into action. 

Balanced brain development is dependent on  outside influences.

At precise times during development, various environmental factors must interact with the senses to turn on the genes to signal a new brain-building process to begin. The more a brain cell is stimulated, the more it will increase in size and processing speed, strengthen its connections, and form new synapses.

Although the brain is able to provide a certain amount of stimulation on its own – dreaming is the best example – it is mostly dependent on outside sources to spark neural growth. The two most powerful sources of stimulation, are movement and a parent’s touch. Others are light, sound, odor, taste, temperature, and gravity.

We know that muscle movement is important motor stimulation for the brain. If kids don’t move, their brains don’t grow. It’s why it is so important for kids to get off the computer and away from the television and go outside and play!

As powerful as these positive environmental forces are, there are negative forces in the environment that turn off these genes. There is plenty of evidence showing that certain lifestyle choices and environmental influences can interfere with healthy brain development (and they are discussed in depth in Disconnected Kids). They include:

  • Lack of physical exercise
  • Overweight and obesity
  • Environmental toxins
  • Poor nutrition and food choices
  • Absentee parenting
  • Television and computers
  • Stressful pregnancy and birth
  • A stressful lifestyle

 In the brains of children with neurological disorders, such as autism, ADHD and oppositional disorders, we can see that certain genes are not being expressed. It’s as if they are stuck in the off position. This is why paying attention to developmental milestones is so important. It is the best tool parents have to help them evaluate if the brain is growing properly — or if it is growing out of balance.