Background

Repetitive Transcranial Magnetic Stimulation (rTMS) has shown initial promise in combating age-related cognitive decline and dementia. The nature and severity of cognitive aging, however, varies markedly between individuals.

Objective/hypothesis

We hypothesized that the distinct constellation of brain changes responsible for individual differences in cognitive aging might influence the response to rTMS.

Methods

Cognitive effects of rTMS were evaluated using a rat model of cognitive aging in which aged rats are classified as Aged-Impaired (AI) or -Unimpaired (AU) relative to young (Y) according to their performance in the Morris water maze. Several weeks later, following presentation of a sample odor in an olfactory recognition task, rats received either sham (Y, n = 9; AU, n = 8; AI, n = 9) or intermittent Theta Burst Stimulation (Y, n = 8; AU, n = 8; AI, n = 9). Memory was tested 24 h later.

Results

Recognition memory in the sham and stimulated conditions depended on pre-treatment cognitive status in the aged rats. Y and AU sham rats displayed robust odor recognition, whereas sham-treated AI rats exhibited no retention. In contrast, rTMS treated AI rats showed robust retention, comparable in magnitude to Y, whereas the AU stimulated scored at chance.

Conclusion

Our results are consistent with a perspective that the unique neurobiology associated with variability in cognitive aging modulates the response to rTMS. Protocols with documented efficacy in young adults may have unexpected outcomes in aging or neurodegenerative conditions, requiring individualized approaches.

中文翻译：

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重复经颅磁刺激对老年大鼠的影响取决于治疗前的认知状态：迈向成功认知衰老的个体化干预

背景

重复经颅磁刺激 (rTMS) 在对抗与年龄相关的认知衰退和痴呆症方面显示出初步的希望。然而，认知老化的性质和严重程度因人而异。

目标/假设

我们假设导致认知老化个体差异的大脑变化的不同星座可能会影响对 rTMS 的反应。

方法

rTMS 的认知影响使用认知老化的大鼠模型进行评估，其中老年大鼠根据其在 Morris 水迷宫中的表现相对于年轻 (Y) 被分类为老年受损 (AI) 或未受损 (AU)。几周后，在嗅觉识别任务中呈现样本气味后，大鼠接受假（Y，n = 9；AU，n = 8；AI，n = 9）或间歇性 Theta Burst 刺激（Y，n = 8 ；AU，n = 8；AI，n = 9)。24 小时后测试记忆力。

结果

假和刺激条件下的识别记忆取决于老年大鼠治疗前的认知状态。Y 和 AU 假大鼠表现出强烈的气味识别能力，而假处理的 AI 大鼠没有表现出保留。相比之下，经 rTMS 处理的 AI 大鼠表现出强大的保留，其幅度与 Y 相当，而 AU 刺激则随机得分。

结论

我们的结果与认知衰老变异性相关的独特神经生物学调节对 rTMS 反应的观点一致。在年轻人中具有记录功效的方案可能在衰老或神经退行性疾病中产生意想不到的结果，需要个性化的方法。