Head rotational acceleration characteristics influence behavioral and diffusion tensor imaging outcomes following...

Area of Science:

• Neuroscience
• Biomedical Engineering
• Traumatology

Background:

• Mild traumatic brain injuries (mTBI) from motor vehicle crashes and sports often involve high-rate head acceleration.
• Rotational acceleration is a key mechanism in mTBI, with both magnitude and duration influencing outcomes.

Purpose of the Study:

• To quantify the independent effects of rotational acceleration magnitude and duration on behavioral and neuroimaging outcomes in a rodent model.
• To investigate the relationship between biomechanical factors and microstructural brain changes following mTBI.

Main Methods:

• Utilized a rodent model of rotational acceleration-induced mTBI with a full factorial design varying peak acceleration (214 or 350 krad/s²) and pulse duration (1.6 or 3.4 ms).
• Assessed behavioral outcomes using the Composite Neuroscore (CN), Elevated Plus Maze (EPM), and Morris Water Maze (MWM).
• Analyzed brain microstructure using ex vivo diffusion tensor imaging (DTI) to measure fractional anisotropy (FA).

Main Results:

• No significant locomotor or cognitive deficits were observed in CN or MWM tests.
• A significant main effect of duration was found in the EPM, with longer durations increasing exploratory behaviors.
• DTI revealed significant effects of both magnitude and duration on FA, with the amygdala and gray-white matter interface showing changes.

Conclusions:

• The duration of the rotational acceleration impulse is a critical, often overlooked, factor in mTBI consequences.
• Findings emphasize the importance of biomechanically-grounded animal models for linking behavioral deficits to specific microstructural brain alterations after mTBI.