Micaux Julia, Poiret Clément, Zhao Jingwen, Hajj Aya El, Tillenon Morgane, Habibi Abir Troudi, Mauconduit Franck, Boumezbeur Fawzi, Chiron Catherine, Noulhiane Marion
Paris-Saclay University, CEA, Joliot Institute, NeuroSpin, UNIACT, F-91191 Gif-sur-Yvette, France.
Paris City University, Inserm, U1141 NeuroDiderot, InDev Team, F-75019 Paris, France.
J Integr Neurosci. 2025 Jul 24;24(7):36672. doi: 10.31083/JIN36672.
Accidental hypoxia has detrimental effects on the brain, particularly on the hippocampal subfields (HS), which are highly sensitive to oxygen deprivation and play a crucial role in episodic memory. This raises the question: could freediving training induce anatomical changes in the HS and lead to significant memory deficits? This study aimed to investigate the impact of a season of freediving training on HS anatomy and episodic memory performance, as freedivers represent a unique natural model for studying the effects of repeated voluntary hypoxic exposure on brain function in healthy individuals. Extending previous research, this study assessed these effects over a prolonged training period.
Seventeen male freedivers were evaluated before and after 7 months of training and compared with a control group of 20 non-freediver athletes. HS anatomical volumes were measured using MRI segmentation and episodic memory performance was evaluated using a pattern separation (PS) task. This task specifically targeted HS-related memory processes by distinguishing between three types of items: (i) identical, (ii) similar, and (iii) new.
No significant differences were observed between freedivers and controls in HS volumes or memory performance, either before or after the 7 month training period. A two-way repeated measures ANOVA revealed that freedivers exhibited the same memory pattern as the control group in the PS task. Specifically, both groups performed better with (i) identical items compared with (ii) similar items ( < 0.001) and were less accurate with (ii) similar items compared with (iii) new items ( < 0.001). This aligns with expectations, as distinguishing similar items from previously presented ones is more cognitively demanding than recognizing new items.
These findings suggest that repeated voluntary hypoxic exposure during freediving training does not impair episodic memory function. Freedivers' memory performance remained comparable with that of the control group, with no detectable adverse effects on hippocampal anatomy.
意外性缺氧对大脑有有害影响，尤其是对海马亚区（HS），该区域对缺氧高度敏感且在情景记忆中起关键作用。这就引发了一个问题：自由潜水训练会导致海马亚区发生解剖学变化并导致显著的记忆缺陷吗？本研究旨在调查一个季节的自由潜水训练对海马亚区解剖结构和情景记忆表现的影响，因为自由潜水者代表了一个独特的自然模型，用于研究健康个体中反复自愿性低氧暴露对脑功能的影响。在先前研究的基础上，本研究在延长的训练期内评估了这些影响。
对17名男性自由潜水者在7个月训练前后进行评估，并与20名非自由潜水运动员的对照组进行比较。使用MRI分割测量海马亚区的解剖体积，并使用模式分离（PS）任务评估情景记忆表现。该任务通过区分三种类型的项目专门针对与海马亚区相关的记忆过程：（i）相同的，（ii）相似的，和（iii）新的。
在7个月训练期之前或之后，自由潜水者和对照组在海马亚区体积或记忆表现方面均未观察到显著差异。双向重复测量方差分析显示，在PS任务中自由潜水者表现出与对照组相同的记忆模式。具体而言，两组在（i）相同项目上的表现均优于（ii）相似项目（<0.001），而在（ii）相似项目上的准确性低于（iii）新项目（<0.001）。这与预期相符，因为将相似项目与先前呈现的项目区分开来比识别新项目在认知上要求更高。
这些发现表明，自由潜水训练期间反复自愿性低氧暴露不会损害情景记忆功能。自由潜水者的记忆表现与对照组相当，对海马解剖结构没有可检测到的不利影响。
