Neuroscience 101 What’s Going On Inside the ADHD Brain

Neuroscience 101 What’s Going On Inside the ADHD Brain

Adapted from an article from ADDitude Magazine written by Larry Silver, M.D.

ADHD Nuts and Bolts Photo

You or someone you love, teach or work with has ADHD. You know what this means on the outside, but do you really understand what is going on inside the brain of someone with ADHD? Why you or they can’t just “snap out of it?” Understanding the science can lead to a greater understanding of the person and what can help. Here’s what you need to know.

How Neurotransmitters Work and Brain Anatomy
There are millions of cells, or neurons, densely packed into various regions of the brain. Each region is responsible for a particular function. Some regions interact with our outside world, interpreting vision, hearing, and other sensory inputs to help us figure out what to do and say. Other regions interact with our internal world — our body — in order to regulate the functions of our organs.

For the various regions to do their jobs, they must be linked to one another with extensive “wiring.” Of course, there aren’t really wires in the brain. Rather, there are myriad “pathways,” or neural circuits, that carry information from one brain region to another.

Information is transmitted along these pathways via the action of neurotransmitters (scientists have identified 50 different ones, and there may be as many as 200). Each neuron produces tiny quantities of a specific neurotransmitter, which is released into the microscopic space that exists between neurons (called a synapse), stimulating the next cell in the pathway — and no others.

How does a specific neurotransmitter know precisely which neuron to attach to when there are so many other neurons nearby? Each neurotransmitter has a unique molecular structure — a “key,” if you will — that is able to attach only to a neuron with the corresponding receptor site, or “lock.” When the key finds the neuron bearing the right lock, the neurotransmitter binds to and stimulates that neuron.

Neurotransmitter Deficiencies
Neuroscientists have found that deficiencies in specific neurotransmitters underlie many common disorders including: anxiety, mood disorders, anger-control problems, and obsessive-compulsive disorder.

ADHD was the first disorder found to be the result of a deficiency of a specific neurotransmitter — in this case, norepinephrine — and the first disorder found to respond to medications to correct this underlying deficiency. Like all neurotransmitters, norepinephrine is synthesized within the brain. The basic building block of each norepinephrine molecule is dopa; this tiny molecule is converted into dopamine, which, in turn, is converted into norepinephrine.

A Four-Way Partnership
ADHD seems to involve impaired neurotransmitter activity in four functional regions of the brain:

Frontal cortex – This region orchestrates high-level functioning: maintaining attention, organization, and executive function. A deficiency of norepinephrine within this brain region might cause inattention, problems with organization, and/or impaired executive functioning.
Limbic system – This region, located deeper in the brain, regulates our emotions. A deficiency in this region might result in restlessness, inattention, or emotional volatility.
Basal ganglia – These neural circuits regulate communication within the brain. Information from all regions of the brain enters the basal ganglia, and is then relayed to the correct sites in the brain. A deficiency in the basal ganglia can cause information to “short-circuit,” resulting in inattention or impulsivity.
Reticular activating system – This is the major relay system among the many pathways that enter and leave the brain. A deficiency in the RAS can cause inattention, impulsivity, or hyperactivity.
These four regions interact with one another, so a deficiency in one region may cause a problem in one or more of the other regions. ADHD may be the result of problems in one or more of these regions.

Trial and Error
We don’t know which brain region is the source of ADHD symptoms. Nor can we tell whether the problem lies with a deficiency of norepinephrine itself or of its chemical constituents, dopa and dopamine. Thus, doctors must rely on clinical experience to determine which medication to try for each child, and at what dosage.

Someday, when our knowledge of the brain is greater, the diagnosis and treatment of ADHD will be more nuanced. Instead of diagnosing simply “ADHD,” and prescribing a stimulant, we might be able to say, “Billy’s ADHD is caused by a deficiency of dopa in the frontal cortex, so he needs medication A,” or “Mary has a type of ADHD caused by a deficiency of dopamine in the limbic system, so she needs medication B,” or “José has ADHD caused by a deficiency of norepinephrine in the reticular activating system, and he needs medication C.”

What do ADHD medications do? In simple terms, they raise the level of norepinephrine within the brain. (Stimulants work by causing the brain to synthesize more norepinephrine; nonstimulants by slowing the rate at which norepinephrine is broken down.) Once the level of neurotransmitter is where it should be, the brain functions normally. The individual becomes less hyperactive, inattentive, and/or impulsive. Once the drug wears off, the level falls — and symptoms return.

Now that you have the basic information neuroscience has to offer about the brain, ADHD and various pharmaceutical measures, you can have an informed conversation with your doctor, psychiatrist or other medication manager.  Whether you decide to try medications or not, what experts know for sure is that professional coaching with a certified, experienced ADHD specialist can make an enormous impact on the well-being, happiness and daily productivity of someone with ADHD.  I encourage you to contact me at or 504-261-1026 to discuss how we can work together to help you or your loved one implement life changing strategies for ADHD management.