Locomotion involves movement. Darrel Boyd Harmon, a noted researcher, once made the statement that all movement was meaningful. The early reflexes lay down the foundation of how we will learn.
One of the earliest reflexes is suckling. That begins the learning of how to put your fingers and objects into your mouth. The tongue is the strongest muscle of the body, and over time we learn to use it for communication.
Another early reflex is the TNR or Tonic Neck Reflex. When a child is sleeping, they typically will have drawn one hand up that is close to the face and the opposite leg. Very often the hand that is closest will become the dominant writing hand. It is our firm belief that no child should be intentionally switched from their preference of writing style.
What may appear as random thrashing and movement, begins to lay a neurological foundation that will continue to build and develop over time as the child gains more gross and then fine motor control.
The one major constantcy of our universe is gravity. We can change all other aspects such as light-dark, cold-hot, but we must learn to overcome and use gravity to our advantage. This is where the early development of up/down, right left, front/back begin to be LEARNED. Their are no reflexes or or other learning tools to form the basis of directonality but through this form of learning sequence.
One of the best layman's books available is How to Develop Your Child's Intelligence by Dr Jerry Getman.