Title: Understanding, Predicting and Preventing Concussion Susceptibility

Speaker: Saara Mansoor, PhD Student, Department of Medical Neuroscience, Dalhousie University 

Date: Tuesday, November 4th, 2025

Time: 11:30am - 12:30pm  

Location: 3H-01 Tupper Building

Description: 

Repetitive mild traumatic brain injuries (rmTBI) are common in contact sports and military settings, yet individuals differ greatly in their vulnerability to long-term neurological consequences. To model this variability, we used 9-week-old Sprague Dawley rats that underwent four rmTBIs. Neurological Severity Scores (NSS) revealed a bimodal distribution after the second injury, allowing animals to be classified as “susceptible” or “resilient.”

We investigated the biological basis of this divergence, focusing on the hypothalamic–pituitary–adrenal (HPA) axis. Susceptible rats consistently showed a blunted corticosterone response to stress, which we traced to adrenal rather than central dysfunction. Pharmacological enhancement of glucocorticoids promoted resilience, underscoring the role of hormone modulation in protection and recovery after rmTBI.

To determine whether HPA axis impairment is innate or injury-induced, we conducted ACTH stimulation tests before and after the rmTBI protocol. Our findings indicate that innate variability in adrenal responsiveness predicts which animals are more likely to be susceptible to concussion. Current work is aimed at further dissecting the mechanisms underlying this susceptibility and resilience, including whether pre-injury traits such as social dominance contribute to susceptibility.