Repeated long-term sub-concussion impacts induce motor dysfunction in rats : a potential rodent model
- Authors: Lavender, Andrew , Rawlings, Samuel , Warnock, Andrew , McGonigle, Terry , Hiles-Murison, Bailey , Nesbit, Michael , Lam, Virginie , Hackett, Mark , Fitzgerald, Melinda , Takechi, Ryusuke
- Date: 2020
- Type: Text , Journal article
- Relation: Frontiers in Neurology Vol. 11, no. (2020), p.
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- Description: Whilst detrimental effects of repeated sub-concussive impacts on neurophysiological and behavioral function are increasingly reported, the underlying mechanisms are largely unknown. Here, we report that repeated sub-concussion with a light weight drop (25 g) in wild-type PVG rats for 2 weeks does not induce detectable neuromotor dysfunction assessed by beamwalk and rotarod tests. However, after 12 weeks of repeated sub-concussion, the rats exhibited moderate neuromotor dysfunction. This is the first study to demonstrate development of neuromotor dysfunction following multiple long-term sub-concussive impacts in rats. The outcomes may offer significant opportunity for future studies to understand the mechanisms of sub-concussion-induced neuropsychological changes. © Copyright © 2020 Lavender, Rawlings, Warnock, McGonigle, Hiles-Murison, Nesbit, Lam, Hackett, Fitzgerald and Takechi.
Effects of sub-concussion on neuropsychological performance and its potential mechanisms : a narrative review
- Authors: Rawlings, Samuel , Takechi, Ryusuke , Lavender, Andrew
- Date: 2020
- Type: Text , Journal article , Review
- Relation: Brain Research Bulletin Vol. 165, no. (2020), p. 56-62
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- Description: Concussion and mild traumatic brain injury (mTBI) are recognised as serious medical events that are relatively common in contact sports. Recently, the seemingly non-injurious phenomenon of sub-concussion has gained interest among neuroscience researchers and early studies are showing that there may be some acute and chronic effects on brain health and function with repeated sub-concussive events of the type seen in soccer, where players strike the ball with the head, and collision sports like the rugby codes. The aim of this narrative review is to describe sub-concussion and the current understanding of short and long term effects of repeated minor impacts that have been found to occur in human and animal models. Here, potential mechanisms for cognitive dysfunction following sub-concussion and recommend directions for future research are discussed. The Potential mechanisms of injuries resulting from sub-concussion such as changes in blood brain barrier integrity, neuroinflammation, cognitive impairment, and oxidative stress damage, among other changes in central nervous system function vary considerably making understanding of the underlying causative mechanism challenging for researchers. Some evidence suggests a link between impaired cerebrovascular function and cognitive impairment which poses a potential mechanism linking the two. It is hoped that this review helps guide researchers toward a potential direction of investigations. © 2020
The effect of sub-concussive impacts during a rugby tackling drill on brain function
- Authors: McNabb, Colm , Reha, Tahere , Georgieva, Julia , Jacques, Angela , Netto, Kevin , Lavender, Andrew
- Date: 2020
- Type: Text , Journal article
- Relation: Brain Sciences Vol. 10, no. 12 (2020), p. 1-12
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- Description: Concussion is known to detrimentally affect brain health. Rugby tackles commonly occur with high collision force between tackler and ball carrier, and low impact head contact is not uncommon. Cognitive deficits following a bout of soccer ball heading has been attributed to the impact and termed sub-concussion. Although soccer ball heading studies provide evidence for acute effects of sub-concussion, it is unknown whether this phenomenon occurs following rugby tackles. This study investigates the acute effects of rugby tackles on brain function and balance in rugby players. Twenty-six volunteers were assigned to either the ball carrier (9), tackler (9) or control (8) group. Controls performed running without the tackle. Outcome measures included corticomotor function using transcranial magnetic brain stimulation (TMS) and balance was assessed by a series of tasks performed on a NeuroCom Balance Master before and immediately after a tackle training drill. Following the tackling bout, the cortical silent period (cSP) increased for the tacklers with no change for ball carrier and control groups, and no differences between groups for balance measures were observed. Lengthening of cSP observed in the tacklers following the bout has been reported in studies of concussion and may indicate long term detrimental effects. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.