Loudness dependence of auditory evoked potentials (LDAEP) has long been considered to reflect central basal serotonin transmission. However, the relationship between LDAEP and individual serotonin receptors and transporters has not been fully explored in humans and may involve other neurotransmitter systems. To examine LDAEP's relationship with the serotonin system, we performed PET using serotonin-1A (5-HT1A) imaging via [11C]CUMI-101 and serotonin transporter (5-HTT) imaging via [11C]DASB on a mixed sample of healthy controls (n = 4: 4 females, 0 males), patients with unipolar (MDD, n = 11: 4 females, 7 males) and bipolar depression (BD, n = 8: 4 females, 4 males). On these same participants, we also performed electroencephalography (EEG) within a week of PET scanning, using 1000 Hz tones of varying intensity to evoke LDAEP. We then evaluated the relationship between LDAEP and 5-HT1A or 5-HTT binding in both the raphe (5-HT1A)/midbrain (5-HTT) areas and in the temporal cortex. We found that LDAEP was significantly correlated with 5-HT1A positively and with 5-HTT negatively in the temporal cortex (p < 0.05), but not correlated with either in midbrain or raphe. In males only, exploratory analysis showed multiple regions in which LDAEP significantly correlated with 5-HT1A throughout the brain; we did not find this with 5-HTT. This multimodal study partially validates preclinical models of a serotonergic influence on LDAEP. Replication in larger samples is necessary to further clarify our understanding of the role of serotonin in perception of auditory tones.

中文翻译：

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用正电子发射断层扫描检查听觉诱发电位响度依赖性的基础

长期以来，听觉诱发电位的响度依赖性 (LDAEP) 一直被认为反映了中枢基础血清素传输。然而，LDAEP 与个体血清素受体和转运蛋白之间的关系尚未在人类中得到充分探索，可能涉及其他神经递质系统。为了检查 LDAEP 与血清素系统的关系，我们通过 [11C]CUMI-101 使用血清素-1A (5-HT1A) 成像和通过 [11C]DASB 的血清素转运蛋白 (5-HTT) 成像对健康对照的混合样本进行了 PET （n = 4：4 名女性，0 名男性）、单相（MDD，n = 11：4 名女性，7 名男性）和双相抑郁患者（BD，n = 8：4 名女性，4 名男性）。对这些相同的参与者，我们还在 PET 扫描的一周内进行了脑电图 (EEG)，使用不同强度的 1000 Hz 音调来唤起 LDAEP。然后，我们评估了中缝 (5-HT1A)/中脑 (5-HTT) 区域和颞叶皮层中 LDAEP 与 5-HT1A 或 5-HTT 结合之间的关系。我们发现 LDAEP 与颞叶皮层中的 5-HT1A 呈显着正相关，与 5-HTT 呈显着负相关（p < 0.05），但与中脑或中缝均不相关。仅在男性中，探索性分析显示多个区域中 LDAEP 与整个大脑的 5-HT1A 显着相关；我们在 5-HTT 中没有发现这一点。这项多模式研究部分验证了血清素对 LDAEP 影响的临床前模型。有必要在更大的样本中进行复制，以进一步阐明我们对血清素在听觉音调感知中的作用的理解。