Individuals with ADHD who come to see me for therapy often ask what is going on in their brain, and how their brain is different from “normal people’s” brains. I struggle to answer this question because 1. I don’t want to spend too much of our time together lecturing about the latest literature on the neuroscience of ADHD. I fear that the information I provide may be too general and not specific to their personal profile of strengths and weaknesses, and 2. I also have to acknowledge the limitations of my own coherent understanding of this aspect of the disorder: however I do continue to learn!
On the other hand I do find the neuroscience of psychological disorders both interesting and enlightening, and potentially useful information for clients regardless of whether it is applied to ADHD, depression, or any other psychological disorder. Somehow being able to locate and see the disorder in the brain can be of high value with clients often exclaiming “oh, this isn’t just me (…a flawed character trait) there is something going on in my brain which I had no choice in and I can see it there in front of me now”.
So here goes: below I present to you four brain areas which are impacted in ADHD, with animations of their location within the brain, and some bits and pieces that I hope readers, clients, mental health professionals, and general community members will find interesting and useful to know in their journey learning about ADHD.
1. The Cerebellum
Highlighted in red in the animation on the left, the cerebellum monitors and regulates motor behaviour. Some studies also link the cerebellum with learning and attention. One theory is that the cerebellum is like a “neuronal learning machine” with the ability to influence the development of other brain regions including areas in the frontal lobe.
The cerebellum is associated with the following functions:
- Coordinating voluntary movement.
- Motor- learning.
- Reflex memory.
- Sequence learning.
Most people with some knowledge of ADHD have heard about the use of stimulant medication as a treatment for ADHD. Neuroimaging studies show that (e.g. Rubia et al, 2009) one of these medications, Methylphenidate (think brand names like Ritalin, Concerta), increases activation in the cerebellum.
Animation: By Polygon data were generated by Database Center for Life Science(DBCLS). – Polygon data are from BodyParts3D, CC BY-SA 2.1 jp, https://commons.wikimedia.org/w/index.php?curid=8956692
2. The Splenium
A sub structure of the corpus callosum, abnormalities in this region of the brain have been observed in ADHD. The corpus callosum connects the right and left sides of the brain.
The corpus callosum is associated with the following functions:
- Allowing information to pass between the left and right hemispheres.
Ever poke your tongue out when you were concentrating on something really hard like a tricky puzzle, drawing, or when cutting something out with scissors?
Some scientists (e.g. D’Agati et. al., 2010) have found that people with ADHD with dysfunction in this area seem to move more than is required for a particular task. They may suffer from “overflow movements” where body parts that are not specifically required to complete a task are moving unnecessarily. This overflow has implications for response control and inhibition.
Animation: By Images are generated by Life Science Databases(LSDB). – from Anatomography website maintained by Life Science Databases(LSDB).You can get and can edit this image through URL below. 次のアドレスからこのファイルで使用している画像を取得できますURL., CC BY-SA 2.1 jp, https://commons.wikimedia.org/w/index.php?curid=7762096
3. The Caudate Nucleus
Highlighted in green, the basal ganglia includes the substructure: the caudate nucleus. The basal ganglia is a group of structures which regulate the initiation of movements, balance, eye movements, and posture.
Other functions associated with this part of the brain include:
- Regulation of movement.
- Skill learning.
- Habit formation.
- Reward systems.
Ever had the feeling that you just cant keep your eyes off something no matter how hard you try?
Several studies indicate that individuals with ADHD have difficulty controlling their eye movements (e.g. Mahone et al, 2011). For example in one eye movement task (the antisaccade task), the individual is presented with a motionless target such as a dot on a screen. A picture is then presented to, say, the right side of the dot and the person is instructed to look to the left of the dot and not at the picture when it is presented. Individuals with ADHD are more likely to make errors, unable to inhibit their reflex action to look at the picture on the right.
Animation: By Danielsabinasz – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=103150668
4. The Frontal Lobe
The frontal lobe is the largest brain structure and associated with the “higher cognitive functions”. The executive functions are located here. The frontal lobe is broadly associated with attention, thought, voluntary movement, decision making, and language.
The frontal lobe is associated with the executive functions which include:
- Emotion regulation.
- Inhibitory control.
- Working memory.
Do you ever find that you give yourself encouragement by saying things like “come on you can do it” either silently in your “inside voice” or out loud so others can hear you?
Most of us would be aware that we sometimes encourage or guide ourselves through difficult tasks using our silent inner voice. In young children this capability is not yet developed. However as children grow they are expected to inhibit audible self-talk and begin to engage in silent inner dialogue more and more to support successful task completion. Studies show (e.g. Berk & Potts, 1991) that children with ADHD engage in more audible self-talk than those without ADHD and those with ADHD experience less attentional gains from self-talk than children without ADHD.
Animation: By Polygon data were generated by Life Science Databases(LSDB). – Polygon data are from BodyParts3D., CC BY-SA 2.1 jp, https://commons.wikimedia.org/w/index.php?curid=9499837
So there we have it. A little about four areas of the brain which are impacted in ADHD. I would encourage anyone to familiarise themselves with the brain and to wrap up this post I am passing on the details of a couple of resources:
One is an app which I have had on my a mobile devices for years called “3D Brain” (Cold Spring Harbour Laboratory). This app is a collection of interactive 3D models of different brain structures so that you can really see and get to know what they look like. I got my version from the apple app store.
Another is the “Whole Brain Atlas” (Harvard Medical School) which is a data set of brain image topographical slices. One of the links contained on this page is a database of the ‘top 100 brain structures’. Here’s the link: https://www.med.harvard.edu/aanlib/
Shannon Quinn – Psychologist – M.P.Psych