The Neurobiology of ADHD

Robert D. Hunt, MD


September 25, 2006

In This Article

The Experience of Attention

Attention is a lot like love. Everyone knows what it is and when it's present, but the multiple components of attention defy easy definition. Attention is the thread that holds together the fabric of our consciousness. For all we know about brain function, the greatest mystery is consciousness itself. How are we aware of what we perceive? How do we know what we know? Attention encompasses the process that allows us to focus on what is important and to filter out what is trivial. Much of this process occurs preconsciously, without effort or awareness. Voluntary attention links the thoughts and emotions we consciously choose to focus on. Because it operates at such a basic level, the process that regulates attention must be very connected to a fundamental sense of self. How we focus our thoughts and feelings is a major expression of self. We ponder what is the "I" that directs our attention.

We know that neurotransmitters such as dopamine and norepinephrine are critical to the language of attention, providing the means of the communication of information across synapses vital to alertness and focus, prerequisites to content. But where, and on what brain systems, do these neurotransmitters operate?

While the nature of attention has been widely discussed, there is a need for an integrative analyses, which is offered here.[1,2,3]


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