In this series, Dr. Laura Chaddock-Heyman, research scientist at the University of Illinois-Champaign, shares how exercise and fitness relate to the brain and why this is of utmost importance for educators.
Catch up on Part 1: Intro + Definitions
Let’s get moving (literally)!
GoNoodle breaks may not only help students get the wiggles out and improve classroom behavior. Here we present evidence that aerobic fitness boosts brain and cognitive health!
In particular, for the second installment of Neuroscience for Teachers, we’ll be answering this important question: How does aerobic fitness influence brain structure and white matter structural integrity in the developing brain?
AEROBIC FITNESS AND BRAIN STRUCTURE
First, let’s explore whether higher fit and lower fit children differ in brain structure, or the volume/size of certain brain areas.
The brain is a large place to explore – with over 100 billion neurons (brain cells)! In conducting this research, we started our exploration of fitness differences in brain structure in the hippocampus, a region known to change with exercise, and a region critical for learning and memory.
Quick anatomy check – if you point your index fingers into your ears, you are pointing to your hippocampus… not to be confused with hippopotamus 😉
Why the hippocampus?
In rodents, aerobic exercise (via wheel running) is known to enhance learning and memory on swimming and maze tasks. Wheel running also enhances the structural integrity of the hippocampus, via the growth and formation of new neurons and blood vessels. The hippocampus is unique in that it is one of the only brain regions to demonstrate continued cell proliferation – or the birth of new neurons – throughout the lifespan.
Aerobic fitness and physical activity positively relate to hippocampal structure in older adults. Aerobically fit older adults have larger hippocampal volumes and better memory performance relative to lower fit peers. Walking three times per week has been found to lead to less structural atrophy in the hippocampus with aging (Erickson et al., 2011). Looking at you, grown-ups!
Do these promising associations between fitness/exercise and the hippocampus extend to children too?
Yes! We found that higher fit 9 and 10-year-old children show larger hippocampal volumes compared to lower fit peers, coupled with superior memory performance (Chaddock et al., 2010a).
This was the first evidence that aerobic fitness also affects the structure of the brain in a developing child population – an important breakthrough for scientists and educators alike!
But new questions arise. Does fitness influence all regions of the brain? Or perhaps specific regions important for certain cognitive skills?
Next we examined whether the structure of the basal ganglia differs in higher fit and lower fit children. The basal ganglia, also known as the striatum, is also buried deep in the brain – near the hippocampus. The basal ganglia is divided into two sections that have different functions: (1) The dorsal striatum (top part) – involved in cognitive control and learning, and (2) The ventral striatum (bottom part) – involved in reward, motivation, and emotion.
Does fitness have specific effects on the structure of the basal ganglia and, in turn, cognition?
Yes! (Chaddock et al., 2010b)
Higher fit children have larger brain volumes in the dorsal striatum and better performance on a task of cognitive control, compared to lower fit peers. In fact, to directly link the brain and cognition – larger volumes in the dorsal striatum were associated with superior cognitive control skills, specifically on a task that involved paying attention and ignoring distractions.
There were no fitness differences in the volume of the ventral striatum. The volume of the ventral striatum was also unrelated to cognitive control.
This study extended the effects of aerobic fitness on the developing brain beyond the hippocampus to the basal ganglia. The results in this area also suggest specificity of fitness differences in brain structure, with fitness differences in dorsal striatum that is involved in cognitive control – and no differences in ventral striatum (not associated with cognitive control).
AEROBIC FITNESS AND WHITE MATTER STRUCTURAL INTEGRITY
The previous studies focus on the structure of brain regions, which generally consist of gray matter.
We also study how aerobic fitness relates to the structure of white matter fiber tracts that carry information between gray matter regions and allow the brain to communicate. We gain insight into white matter structure by measuring the diffusion of water around white matter tracts. To give us a deeper, practical understanding, let’s compare a white matter tract to cheese. Yes, cheese!
If a white matter fiber tract is tight, dense, and fibrous – like string cheese – water does not flow freely in and out of the tract. This tract is said to have “high structural integrity,” in neuroscience terms.
On the other hand, if water flows freely in and out of a white matter tract, like Swiss cheese, this suggests a less dense, less fibrous tract, with less structural integrity.
Higher fit children show greater estimates of structural integrity, or higher estimates of compact, fibrous tracts, in white matter tracts that travel throughout the brain, compared to lower fit children (Chaddock-Heyman et al., 2014).
White matter microstructure may be another potential neural mechanism of aerobic fitness that assists in efficient communication between gray matter and the integration of regions into networks to support cognitive function and academic achievement.
In other words, these results suggest that higher fit children may have speedier transfer of information throughout the brain – which may help boost performance in and out of the classroom.
But of course, aerobic fitness does not only impact brain structure…
Next I will give you a sneak peek of our work on aerobic fitness, physical activity and brain function… and why higher fit children may be supertaskers!
Chaddock, L., Erickson K. I., Prakash, R. S., Kim, J. S., Voss, M. W., VanPatter, M., … Kramer, A. F. (2010a). A neuroimaging investigation of the association between aerobic fitness, hippocampal volume and memory performance in preadolescent children. Brain Research, 1358, 172-183.
Chaddock, L., Erickson, K. I., Prakash, R. S., VanPatter, M., Voss, M. V., Pontifex, M. B., … Kramer, A. F. (2010b). Basal ganglia volume is associated with aerobic fitness in preadolescent children. Developmental Neuroscience, 32, 249-256.
Chaddock-Heyman, L., Erickson, K. I., Holtrop, J. L., Voss, M. W., Pontifex, M. B., Raine, L. B., Hillman, C. H., & Kramer, A. F. (2014). Aerobic fitness is associated with greater white matter integrity in children. Frontiers in Human Neuroscience, 8, 1-7.
Erickson, K. I., Voss, M. W., Prakash, R. S., Basak, C., Szabo, A., Chaddock, L., Kim, J. S., Heo, S., Alves, H., White, S. M., Wojcicki, T. R., Mailey, E., Vieira, V. J., Martin, S. A., Pence, B. D., Woods, J. A., McAuley, E., & Kramer, A. F. (2011). Exercise training increases size of the hippocampus and improves memory. Proceedings of the National Academy of Sciences, 108, 3017-3022.