JULY/AUGUST 2019. DISCOVER 69
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Parietal cortex: Helps
sort through differenttypes of sensory
information and plays a
role in focusing attention.
In ADHD brains: Generally
smaller and less active in
tasks that require attention.
Neural Networks
(^1) Default mode network (DMN): Sometimes called the
“daydream” network; consists of multiple regions and is more
active when not focused on a task.
In ADHD brains: These regions don’t communicate with each
other properly. As a result, the DMN doesn’t shut down when it
should, inhibiting the individual’s focus.
(^2) Frontostriatal network: Made up of the basal ganglia,
ventral anterior cingulate cortex and the dorsal anterior
cingulate cortex; involved in things like executive functions
and reward and motivation.
In ADHD brains: Tends to be less active.
(^3) Cortico-striatal-thalamo-cortical networks: Of the five
networks, two play a role in attention while one is involved in
emotions, another in motor activity and the last in impulsivity.
In ADHD brains: Connections in the networks are dysfunctional,
though research into how this happens isn’t conclusive.
(^4) Frontoparietal network: Involved in timing, executive
functions and decision making.
In ADHD brains: Tends to be less active.
Neurotransmitters
Dopamine: A neurotransmitter, or chemical messenger,
that’s critical for many functions. Dopamine’s roles in
planning, movement, motivation, switching between
tasks and reward processing are key in this disorder.
In ADHD brains: Lower levels are linked to the disorder,
but medications that increase dopamine can alleviate
symptoms.
Norepinephrine/noradrenaline: Another chemical
messenger involved in certain cognitive processes like
working memory, arousal, ability to control inhibitions,
attention, learning and alertness.
In ADHD brains: Like dopamine, norepinephrine functions
abnormally, but medications that increase its levels can
help.
Brain cells
Neurotransmitters
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