ADHD: Brain Differences

00:00 Now let's take a look at the pathophysiology.

00:03 Now before we can talk about the structural differences I just want to do a quick review.

00:08 Take a look at the image that we have there.

00:10 I put three orange boxes there to highlight the frontostriatal tracks.

00:15 I want you to be able to see what we're talking about as we're working through that now. The frontostriatal tracks connect the cortices right to the striatum.

00:24 Now, remember, the striatum is part of the basal ganglia.

00:27 Before we go on, look at those boxes and you'll see the pre-mortal cortex, the orbital frontal cortex and the primary motor cortex.

00:37 So it's those tracks that connect these parts of the cortex to the striatum part of the ganglia.

00:45 Okay. So I know that's a lot of a review.

00:47 You've already had that kind of content.

00:49 But when you're thinking about what's going wrong in the pathophysiology of ADHD these tracks are critically important.

00:57 So the frontostriatal tracks connect the cortices of the brain, the ones that we that we listed there to the striatum.

01:04 The striatum is part of the basal ganglia.

01:08 Now remember what the basal ganglia does that it modulates non-motor cognitive and emotional functions in addition to motor function.

01:16 So this is what's communicating back and forth between the cortices and the basal ganglia. Now I broke this down in a chart.

01:23 Here's a great study sheet for you.

01:25 Just so you can keep this in mind.

01:27 You see, I've got those three tracks right on the left.

01:30 Those were in the orange boxes on the previous slide.

01:33 And let's talk about what they do.

01:35 So you see there that the premotor connects the premotor cortex to the striatum.

01:40 The orbital frontal connects the orbital frontal cortex to the striatum.

01:45 I know you see the pattern there.

01:46 We've just talked about it.

01:48 That's another quick review for you.

01:50 But these charts can help you keep things in mind and get a good foundation as you're studying the rest of the content.

01:57 Now the functions are also there.

01:59 You see the different tracks like the first one, the premotor, that's planning and planning and preparing movements.

02:05 The next one is decision making.

02:07 Reward evaluation, emotional regulation and the motor one directs control of voluntary movements. Now lay that over what you know about ADHD.

02:17 We already know they have.

02:18 They struggle with planning and strategizing and preparing things.

02:23 Decision making have a hard time with prioritization motivation.

02:27 And you see how these three tracks are involved.

02:30 Now I've made that third column role in ADHD.

02:34 What I would like you to do is spend some time thinking through that.

02:38 I would, if I were you, pause the video and see how can I make this connection? How can I make sure this information is relatively sticky in my mind as we go through the rest of the treatment options for ADHD? Now we're going to take a look at the striatum.

03:00 It's the largest structure of the basal ganglia.

03:03 It's not the only structure of the basal ganglia, but it is definitely the largest structure. Now it regulates voluntary movement, habit formation, decision making, and other various cognitive functions.

03:16 So when you're remembering what the striatum does, I want you to think about it as a critical component of the brain's basal ganglia.

03:23 And it's primarily composed of two main structures that you see there in the image the caudate nucleus.

03:29 Now that's superior to the thalamus.

03:32 And the caudate nucleus is involved in motor control, learning, memory and cognitive processes. As you're keeping that in mind about ADHD, it's making a lot of sense, right. The putamen is adjacent to the caudate nucleus.

03:44 And the putamen plays a really key role in motor control and learning because it has its connection with the cortex and other brain regions.

03:52 So we know that the striatum is critically important.

03:56 You go back and you review the frontostriatal tracks.

03:59 Remember their job, their role is to make sure that they connect the cortices to the striatum, part of the basal ganglia.

04:08 Now that you've had that quick review, let's take a look at the structural differences in someone who has ADHD in their brain.

04:14 So the structural differences are most notable in the anterior brain areas.

04:19 We're talking about the prefrontal cortex.

04:22 That's the one that's primarily responsible for all the executive functions and impulse control. Now the basal ganglia are involved in motor response inhibition and routine behavior regulation.

04:33 So we just want you to know that's where the structural differences are mainly going to be their most notable in the anterior brain areas.

04:40 Continuing to look at the functional differences in children's brains with ADHD.

04:45 Two things you want you to keep in mind.

04:47 There's first a dysfunction in the basal ganglia.

04:50 And second, there's diminished dopamine and norepinephrine activity.

04:55 Okay. So those are two key points.

04:58 We're looking at dysfunction in the basal ganglia and diminished dopamine and norepinephrine activity.

05:04 Now let's take a look at the striatum.

05:06 Again I've got I've got a better picture there for you.

05:08 Talking about the dysfunction in the basal ganglia that is present in children with ADHD. Here's a bigger image of the basal ganglia.

05:17 Now on this image you see the caudate and putamen.

05:21 Now these are considered the striatum and one of the main parts of the basal ganglia, as is the Globus pallidus.

05:27 But right now we're going to focus on the caudate and putamen.

05:30 But the basal ganglia is this group of interconnected nuclei that's in the brain.

05:34 That plays a crucial role in movement regulation, as well as various cognitive and emotional functions.

05:40 Now we keep repeating that.

05:42 Yeah, because we wanted this first part to be a strong and solid review for you as you're preparing for practice.

05:49 So you've got it there. You see the basal ganglia.

05:51 We've talked about the caudate and putamen.

05:54 And we know that a child's brain with ADHD has a dysfunction here in this area.

05:59 Now take a look at the frontal subcortical circuits.

06:03 You see that image that we have there to represent the circuits.

06:07 Now these circuits, they're neural pathways that connect the frontal lobes of the brain to the various subcortical structures.

06:14 Now we're talking about things like the basal ganglia as one of the examples of the subcortical structures.

06:19 But it's the basal ganglia the thalamus and the brainstem.

06:23 Now it's these circuits. They play a really important role in integrating cognitive, motor and emotional functions, all which can be impacted by ADHD.

06:32 So there are several key frontal subcortical circuits, and each one is associated with a very specific function.

06:40 The thalamus role in sensory processing and attention and executive function is what makes the thalamus a critical area of interest for you in wanting to understand and manage ADHD, because in ADHD, the thalamus can exhibit some structural and functional abnormalities. That means it could contribute to the disorder symptoms.

07:00 So these abnormalities can affect several key functions.

07:03 But I'm going to put them in three groups or buckets for you to think through.

07:07 So the first group would be attention regulation.

07:10 The second is executive functioning.

07:13 And the third is motor activity.

07:16 The thalamus is involved in all of those.

07:18 But let's unpack that a little more.

07:20 So the first category do you remember what it was.

07:23 Just checking attention regulation.

07:26 Now the thalamus is what helps us filter out and prioritize sensory information.

07:30 If the thalamus is not working, this can lead to difficulties in someone being able to sustain their attention and for them filtering out distractions.

07:39 Remember, that's a classic cardinal sign of ADHD is that the client has difficulty focusing and they get distracted by irrelevant information.

07:49 So first of all, attention regulation that's dealing with the thalamus because it cannot effectively filter and prioritize sensory information as well as a brain without ADHD.

08:01 Second category executive functioning.

08:04 Now you know what executive functioning is.

08:06 But the thalamus interacts with the prefrontal cortex.

08:09 Remember that's the place where you learn to plan, you make decisions, and it is impulse control. If the thalamus has some abnormalities, this can impair your executive functioning. The third and final category is the motor activity.

08:22 Now the thalamus is part of the circuits that regulate motor control.

08:26 So dysfunctions might even contribute to the hyperactivity and impulsivity that you've seen in ADHD.

08:33 So we went back and we reviewed the thalamus.

08:35 We talked about if it might have some structural and functional abnormalities that can contribute to the symptoms of ADHD.

08:42 And these are the three main categories attention regulation, executive functioning and motor activity.

08:49 Now when it comes to comparing the changes in the brain, we've talked about all these have been in regards from the context of children.

08:56 But when you look at adults, the structural and functional abnormalities in the brain are similar. Now perhaps there might be some more cortical and subcortical abnormalities compared with childhood ADHD, but essentially they are very similar.