Gaffney, C. J. | Search bioRxiv

bioRxiv2026

Distinct Neural Signatures of Auditory Processing in Contact versus Non-contact Sports Athletes

Repetitive sub-concussive head impacts are emerging as one of the most urgent and overlooked challenges in neurotrauma. Despite growing evidence of their neurological consequences, there is no validated objective biomarker for early and reliable detection. Cortical (N100) and subcortical (frequency following responses) to a speech syllable presented in (1) quiet and (2) six-talker background noise listening conditions were assessed using EEG in 60 tier-2 athletes (30 contact, 30 non-contact; age-, sex-, height-, body mass- and BMI-matched). Reduced cortical N100 amplitudes in contact athletes were confirmed by a significant group effect (F(1,54) = 9.16, p = .004), indicating early auditory cortical dysfunction as a measurable biomarker of sub-concussive exposure. Contact athletes also exhibited subtle hearing deficits and impaired self-reported speech perception, linking neural changes to real-world communication deficits. These findings were not related to cortical response amplitudes, suggesting that peripheral and cortical changes may occur independently following repetitive head impacts. Response timing and subcortical encoding were unaffected under both listening conditions. Our findings establish a selective auditory cortical vulnerability to repeated sub-concussive head impact exposure, providing the basis of an objective EEG-based monitoring tool that could help support athlete brain health and safety, and inform future research in contact sports.

neuroscience↗

bioRxiv2020

Spaceflight Affects Neuronal Morphology and Alters Transcellular Degradation of Neuronal Debris in Adult Caenorhabditis elegans

Extended space travel, such as crewed missions to Mars and beyond, is a goal for both government space agencies and private companies. Research over the past decades, however, has shown that spaceflight poses risks to human health, including negative effects on musculoskeletal, cardiovascular, and immune systems. Details regarding effects on the nervous system have been less well described. The use of animal models holds great potential to identify and dissect conserved mechanisms of neuronal response to spaceflight. Here, we exploited the unique experimental advantages of the nematode Caenorhabditis elegans to explore how spaceflight affects adult neurons in vivo, at the single-cell level. We found that animals that lived 5 days of their adult life on the International Space Station exhibited considerable dendritic remodeling of the highly branched PVD neuron and modest morphological changes in touch receptor neurons when compared to ground control animals. Our results indicate hyperbranching as a common response of adult neurons to spaceflight. We also found that, in the presence of a neuronal proteotoxic stress, spaceflight promotes a remarkable accumulation of neuronal-derived waste in the surrounding tissues (especially hypodermis), suggesting an impaired transcellular degradation of debris that is released from neurons. Overall, our data reveal that spaceflight can significantly affect adult neuronal morphology and clearance of neuronal trash, highlighting the need to carefully assess the risks of long-duration spaceflight on the nervous system and to develop countermeasures to protect human health during space exploration.

neuroscience↗