Response inhibition is controlled by the thalamus part of the brain. It functions similarly to a gate, sending signals to allow or prevent certain behaviors.

When the neurotypical brain recognizes a red flag, the thalamus sends a warning signal to the pre-frontal cortex. This is the brain's control center, which is in charge of emotional expression and problem resolution.

However, the thalamus "gate" is broken in ADHD brains. This is what causes impulsivity in ADHD brains. As a result, someone with ADHD may find it difficult to:

• Refrain from making a remark that could be hurtful to someone's feelings.

• Rein in short-term desires such as impulse shopping on the internet.

• Keep themselves from interrupting someone who is talking by saying what is on their mind in that moment.

• Wait their turn in line

Impulsivity is reinforced in people with ADHD by the dopamine that is produced by our brains whenever we get something. Since ADHD brains are already deficient on dopamine, it gets that much more stimulated when it is able to get something right away. Thus creating a desire to want instant gratification.