In a recently published study, Dr JAMA Network OpenThe researchers investigated the brain architecture and neurophysiological properties of teenage soccer players.
The neurological effects of head trauma in adolescent football players are evident. Although American football can encourage teamwork, repeated subconcussive injuries can cause neurological problems, especially in young athletes.
Studies have shown that collision sports athletes have lower cortical thickness, but current high school and college football players have reduced brain volume and cortical thinning in the frontotemporal region. Resting-state functional magnetic resonance imaging (RS-fMRI) functional connectivity indicates neurophysiological changes induced by repeated head injury.
About the study
In the current study, researchers used sophisticated neuroimaging techniques to assess brain anatomy and neurophysiology in high school football players and non-contact sports participants.
The team matched adolescent soccer athletes and controlled for non-contact sports such as tennis, swimming, and cross country from five high school sports programs based on age, school, and gender (male). They conducted neuroimaging assessments between May and July 2021 and the following year, and analyzed the data between February and November 2023.
Study participants were exposed to soccer and non-contact sports. Study findings included structural MRI data assessed for cortical sulcal depth, thickness, gyrification, RS-fMRI data, amplitude of low-frequency fluctuations (ALFF), resting state-functional connectivity (RS-FC), and regional homogeneity (ReHo). included .
The cohort consisted of individuals ages 13 to 18 who were current members of a high school football team or non-contact sports team. They excluded subjects with moderate to severe traumatic brain injury (TBI), control athletes who participated in organized contact sports, and those with a history of MRI contraindications.
Initially, the team created a reference volume and its skull-free version and co-registered the BOLD reference to T1-weighted images. They excluded individuals with head movements and frame-based displacements greater than 3.0 mm and 3.0 degrees from the fMRI analysis, resampling the BOLD time series into their original, native space. The team chose the dorsolateral prefrontal cortex (DLPFC) as a region of interest (ROI) because of its involvement in brain damage. The cohort included age, number of prior injuries, body mass index (BMI), Patient Health Questionnaire (PHQ-9) score for depression, generalized anxiety disorder (GAD-7) score for anxiety, and intracranial volume as study variables.
A total of 275 men (205 footballers; 189 white individuals (92%), five Asian and eight black or African American; 70 controls; 64 white individuals (92%), four Asian and one African American or black) were analyzed. . The average participant age was 16 years. The footballers showed significant thinning of the cortex, particularly in fronto-occipital regions such as right precentral gyri and left superior frontal gyri compared to controls.
In contrast, soccer players had increased cortical thickness in the left cingulate cortex and caudal cingulate cortex in the posterior and anterior regions of the right brain, respectively. Soccer players showed greater sulcal depth compared to controls in the precuneus, precentral gyri, and cingulate cortex, particularly in the parietal lobe and the caudal cingulate cortical region of the right anterior inferior aspect of the brain.
Compared to controls, soccer players showed increased gyrification in several regions of both hemispheres, including the frontoparietal area, cingulate cortex, lingual gyrus, and precuneus. In contrast, the team observed less gyrification in the caudal parietal gyri, superior temporal gyri, pars orbitalis gyri, and caudal cingulate cortices of the forebrain.
The team detected significantly lower values of ALFF in the footballer’s cingulate cortex and frontal lobe, including the left trigeminal, superior and middle frontal gyri; precentral gyrus; anterior and middle cingulate cortices; and bilateral internal regions. Conversely, they observed enhanced ALFF in the medial occipital area of the left brain of soccer players, including the calcarine sulcus and lingual gyrus.
Similarly, the team observed significantly higher regional homogeneity in occipitotemporal brain regions in footballers compared to controls, including the calcarine sulcus, middle, lingual and inferior occupational gyri, and inferior and middle temporal gyri. In contrast, the team observed significantly less regional homogeneity in right and left precentral gyri and midbrain regions, including bilateral posterior and middle cingulate cortex, putamen, and insula.
Overall, the study found cortical thinning in frontal and occipital regions, thickening in the cingulate cortex, greater sulcal depth, and greater gyrification in the brains of adolescent soccer players compared to controls. Local brain activity patterns revealed lower ALFF in the frontal region and higher ALFF in the occipital region. Coherence of brain signals was similar with lower ReHo in central and frontal regions and higher ReHo in occipitotemporal regions. Research findings also highlight the continued growth and maturation of cortical gyri and sulci necessary for developmental trajectories from childhood to adolescence.