Scientists are still trying to unravel the causes of learning disorders. What they do know is that they are much more complex and varied than at first thought. New evidence appears to indicate that most learning disabilities do not stem from a single, specific area of the brain but rather from problems in assimilating information from various brain areas. It is thought that learning difficulties may have their origin in minor disturbances in brain structures and functions which occur before birth. In the fetus, the baby begins to acquire the specialist brain cells, the neurons. The brain stem also grows, as do the two "hemisperes" or sides of the brain and the nerve cells which specialise in passing data back and forth between different parts of the brain. If all goes well, the areas which handle sensory processing, language, thinking, emotions and attention will develop normally. However, the theory goes that if there are disruptions at this stage, deficits in the brain's ability to interconnect may lead to learning difficulties. Researchers also suspect genetic factors, as learning disorders often run in families, although family environmental factors may play a part too. Parental abuse of alcohol and drugs can seriously affect brain development in the fetus, while environmental toxins and problems during childbirth have also come under scrutiny in recent years. It's an exciting time in brain research and what is beyond doubt is that we are learning more about the brain and its relationship to learning disorders as each year passes!