Concussion - What happens to the brain? PART 1

Functional magnetic resonance imaging (fMRI) shows changes in the outer (cortical) and inner (subcortical) areas of the brain in chronic concussion syndrome, post-concussion syndrome (PCS). Including reduced resting state or resting activity in the brain and changes in brain activation patterns. A study from 2020 has shown a significant reduction in functional connections between several external and internal areas. Including areas called the prefrontal cortex, superior parietal cortex and temporal cortex. These are areas that are important for, among other things, the coordination and processing of different sensory impressions, and coordination between them is important for good cognitive function and good ability to orient and move. Another study from 2019 used structural MRI (conventional MRI) to detect changes in the thickness of the outer parts of the brain in these areas in people with post-commotio syndrome.

Research using electroencephalography (EEG) has also shown functional changes in post-commotio syndrome. In 2019, changes were detected in both cortical and subcortical areas, with both increases and decreases in activity in different areas of the brain. These changes appear to be associated with impaired cognitive function in people with post-commotio syndrome. In addition, a previous study from 2018 shows that people with post-commotio syndrome have disturbances in cortical network dynamics, with a decrease in small world brain networks and increased modular organization.

Good changes to the brain's small world brain network involve adjustments to how neurons and their connections are organized so that information can be transferred efficiently and effortlessly. These changes can lead to increased information flow and improved cognitive function, and can be the result of learning, experience or healing processes after injury. Good regulation of this network contributes to neuroplasticity and the brain's ability to adapt to different situations and demands. Disruptive changes resulting from an injury, disease or developmental disorder reduce the brain's capacity for neuroplasticity, making it more challenging and energy demanding to adapt to new situations.    

Modular organization in the brain refers to the way neurons and their connections are grouped into separate but functionally related clusters, called modules. These modules are specialized to process different types of information or perform specific tasks. Modular organization contributes to efficient information processing, as modules can work independently while interacting with other modules when necessary. This network of modules enables rapid and flexible adaptation to new situations and learning experiences, contributing to neuroplasticity and the brain's ability to adapt and evolve. In people with post-commotio syndrome, there is increased modular organization, probably as a result of a number of compensatory mechanisms in an attempt to compensate for primary and secondary functional impairments.   

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Function and dysfunction in the outer and inner parts of the brain.  

To gain a better understanding of what happens in the brain in a concussion and what causes the wide range of symptoms associated with a concussion, we need to review the functions of some of the areas of the brain and what happens to them in a head trauma. We will do this in part 2 of this article which will be published in a few weeks.   

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