Attention is a kind of state of mind,
in which, there is a maintenance of awareness, persistently, on particular mental activity for a period.
Neuroanatomically,three structures in the brain is important for attention: Ascending reticular activating system, thalamus, and cortex(mainly right frontal lobe).In terms of neuronal activity, it is the result of synchronization of neuronal firing in various parts of cortex .
Why some children are unable to focus on particular activity?
It is because of easy distractibility or attention deficit.
And they became hyperactive, jumping from one activity to another.
Which may be socially inappropriate.And society may respond negatively to such children.
The children may develop low self esteem and defensive kind of rebellious behaviour,even to conduct disorder and substance abuse
Modern science is searching for the reason.
It can be due to prenatal(during pregnancy) exposure to food additives, food colouring agents.preservatives,toxins, and sugar.In my experience of clinical evaluation, most of the mothers of children with ADHD have a history of exposure to ‘moderate to severe’ stress during pregnancy.