Brain imagingBrain imaging provides us with a means of photographing the brain and watching it as it works. There are several different methods of imaging:
Many studies using these imaging techniques have been conducted with ADHD children...
So what do we know about ADHD from these brain imaging techniques?
Using the methods presented above, researchers have begun to find differences between ADHD children and non-ADHD children. Up until recently, most of the imaging studies have been structural (CT and MRI scans), this means that they take static pictures of the brain.
Brain Imaging - Structural
The evidence has highlighted structural differences between ADHD and non-ADHD
children. The majority of this evidence suggests that a region known as the
frontal cortex is involved in ADHD (the orange coloured area in the
picture below right).
The frontal cortex is part of the cerebral cortex (or the outer
surface of the brain). The cerebral cortex is broken up into 4 lobes:
(All of these areas are highlighted in the picture below)
The frontal cortex is involved mainly with executive functions. These include:
Brain imaging - functionalNew technology has allowed us to advance from looking at the brain through static imaging techniques (such as CT scans and MRI scans). Now we have functional imaging techniques (SPECT & fMRI) which allow researchers to view the brain while is works - a moving picture if you like.
Functional studies have exposed a decrease in the metabolic activity in the right frontal lobe, but also in an area known as the basal ganglia (this region is responsible for regulating movement and is connected with the frontal lobe region).
Recently these functional imaging techniques have pointed at 3 areas closely related to the basal ganglia, believed to be responsible for the symptoms of ADHD:
Some researchers believe that problems in the circuit between these three regions are the underlying mechanisms that cause ADHD symptoms.
How does Ritalin and other medication help?:
Despite it's wide spread therapeutic use over the last 50 years, little is known about how Ritalin works. New research, however, has provided us with insight into the mechanisms of Ritalin in the brain - Click here to read more.
One more thing:
The evidence suggested here is simply an introduction. Unfortunately there is a lot of variance in ADHD data (some imaging studies have found left hemisphere disfunction rather than right) and it is difficult to know what to believe.
For further articles on the neurobiology of ADHD, including a review of the imaging studies, Click here.
This page is continually being updated as new data comes to hand.
We will make you aware of any future developments.
This page was last modified 030708.