The Neurobiology of ADHD

Robert D. Hunt, MD


September 25, 2006

In This Article

Components of Attention

To understand attention, one must first deconstruct its components. A process as complex as attention is not one process but many processes acting in concert. Attention must encompass at least these components:

  • Arousal and alertness -- the prerequisites to attention

  • External or receptive attention: sensory processing and interpretation -- as with reading

  • Internal or reflective attention which includes thinking about ideas, concepts, and organization of projects or tasks

  • Processing attention or selective attention. This includes:

    1. Focus -- tuning in to an object or topic

    2. Filtering -- signal:noise gradient -- enhancement or activation of relevant stimuli

    3. Inhibition of sensation (sensory inhibition) -- selective sensory input

  • External or expressive attention -- encompasses what we choose to communicate or suppress, which also evokes components of focusing, filtering, and inhibition.

  • Working memory -- accessing the retrieval and storage of working memory, ie, the flow of information, the content of active thought


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