Concussion-related disruptions to hub connectivity in the default mode network are related to symptoms and cognition

Abstract

Concussions present with a myriad of symptomatic and cognitive concerns; however, the relationship between these functional disruptions and the underlying changes in the brain are not yet well understood. Hubs, or brain regions that are connected to many different functional networks, may be specifically disrupted after concussion. Given the implications in concussion research, we quantified hub disruption within the default mode network (DMN) and between the DMN and other brain networks. We collected resting-state functional magnetic resonance imaging data from collegiate student-athletes (n = 44) at three timepoints: baseline (prior to beginning their athletic season), acute post-injury (approximately 48 hours after a diagnosed concussion), and recovery (after starting return-to-play progression, but prior to returning to contact). To link these connectivity changes to clinical outcomes, self-reported symptoms and computerized cognitive assessments were collected across similar timepoints. Functional connectivity between regions within in the DMN increased from baseline to post-injury and decreased from post-injury to recovery. The relationship between functional connectivity and symptoms was stronger post-injury than at baseline and recovery. Similarly, the relationship between functional connectivity in the DMN and visual memory performance was stronger post-injury than at baseline and recovery. In addition, functional connectivity between DMN hubs and visual network non-hubs decreased from baseline to post-injury and increased from post-injury to recovery. The relationship between somatic symptoms and functional connectivity between DMN hubs and visual network non-hubs was also stronger post-injury. The relationship between visual memory performance and functional connectivity between DMN hubs and visual network non-hubs was also stronger post-injury. These results highlight a unique relationship between self-reported symptoms, visual memory performance and acute functional connectivity changes involving DMN hubs after concussion in athletes. This may provide evidence for a disrupted balance of within- and between-network communication highlighting possible network inefficiencies after concussion. These results aid in our understanding of the pathophysiological disruptions after concussion and inform our understanding of the associations between disruptions in brain connectivity and specific clinical presentations acutely post-injury.

Resting-state causal brain connectivity in youth female athletes suggest sex-related differences following subacute concussion

“…Greater magnitudes of information flow (stronger connectivity) in the concussed group compared to the control group align with numerous reports of increased functional connectivity in the acute phase of concussion (9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19). The significantly higher magnitudes of information flow are suggestive of hyperconnectivity, indicating that the concussed female youth brain exerts more effort at rest compared to a healthy, uninjured brain.…”

“…The DMN is a network of cerebral regions that show coordinated activity during wakeful rest and is associated with self-referential emotions and mind-wandering thoughts (8). Although not entirely undisputed, it is commonly reported that the acute phase after injury has increased functional connectivity (9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19). Reduced anterior connectivity paired with increased posterior connectivity has also been commonly reported (20)(21)(22)(23)(24)(25).…”

Self-reported concussion history is not related to cortical volume in college athletes

“…Many of the adverse outcomes related to concussion history can be viewed through the lens of network neuroscience. In fact, concussion is increasingly being considered as an injury characterized by disruptions to structural and functional brain connectivity (41)(42)(43)(44)(45). These network disruptions have been linked with many of the behavioral outcomes of concussion history including cognitive impairment (46)(47)(48), emotion disruptions including depression (49)(50)(51), and changes in motor function (52).…”

Progressive lifespan modifications in the corpus callosum following a single juvenile concussion in male mice monitored by diffusion MRI

“…Concussion awareness has increased considerably over the last decade particularly in sports-related brain injuries (Snyder and Giza 2019). Altered brain connectivity is a signature of concussion injuries both in the acute and in the chronic epochs (Hayes, Bigler et al 2016, Bouchard, Higgins et al 2023, Onicas, Deighton et al 2023). Broadly, these studies report decrements in structural (diffusion magnetic resonance imaging (MRI)) and functional (evoked or resting state MRI) connectivity between affective, motor and somatic brain regions.…”