Kadoya C, Wada S, Matsuoka S
Department of Neurosurgery, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
J UOEH. 1988 Mar 1;10(1):11-30. doi: 10.7888/juoeh.10.11.
The present study was carried out on animals and humans in order to clarify auditory dominancy or lateralization and the contribution site of auditory evoked middle latency responses (AEMLRs). Normal AEMLRs on guinea pigs and humans were quite similar and consisted of two negative and two positive peaks between 8 and 50 msec following the start of an auditory stimulus. In normal human subjects, the component Pa (peak to baseline measurement) or Na-Pa (trough to peak measurement) was significantly greater in the temporal area contralateral to the stimulated ear than in the ipsilateral temporal area. In guinea pigs, however, AEMLRs were attenuated only by stimulation contralateral to the side, on which a lesion was made by unilateral aspiration of the lemniscus or the inferior colliculus. This auditory lateralization and contralateral dominancy were also verified by the direct cortical recording of AEMLRs in humans and also by analysis of auditory evoked brain mapping. In clinical studies, AEMLRs have been obtained even in a premature infant born after a 44-week pregnancy. In patients with well localized lesions of the brain stem, all components of the AEMLR to stimulation contralateral to the lesion side were affected. However, component Pa of the response to stimulation contralateral to the lesion was mainly abolished in patients with unilateral thalamic or temporal lesions. The following results were obtained: 1) component Pa (or Na-Pa) of AEMLR has significant lateralization, 2) the generation site of Pa may be in the subcortical thalamic projection of the contralateral lobe, 3) component Po (or No-Po) is a true neurogenic response but is frequently enhanced by the post-auricular reflex, 4) the contralateral inferior colliculus is very important for the generation of Po, 5) the auditory system (hearing) may have contralateral AEMLR dominancy.
本研究在动物和人类身上进行，以阐明听觉优势或听觉偏侧化以及听觉诱发中潜伏期反应（AEMLR）的产生部位。豚鼠和人类的正常AEMLR非常相似，由听觉刺激开始后8至50毫秒之间的两个负峰和两个正峰组成。在正常人类受试者中，刺激耳对侧颞区的Pa成分（峰到基线测量）或Na - Pa成分（谷到峰测量）明显大于同侧颞区。然而，在豚鼠中，仅通过刺激与单侧损毁内侧丘系或下丘的一侧对侧的部位，AEMLR才会减弱。这种听觉偏侧化和对侧优势也通过对人类AEMLR的直接皮层记录以及听觉诱发脑图谱分析得到了证实。在临床研究中，即使是妊娠44周后出生的早产儿也能记录到AEMLR。在脑干病变定位良好的患者中，病变侧对侧刺激的AEMLR的所有成分均受到影响。然而，在单侧丘脑或颞叶病变的患者中，病变对侧刺激反应的Pa成分主要消失。获得了以下结果：1）AEMLR的Pa成分（或Na - Pa）具有明显的偏侧化；2）Pa的产生部位可能在对侧叶的皮质下丘脑投射区；3）Po成分（或No - Po）是真正的神经源性反应，但常被耳后反射增强；4）对侧下丘对Po的产生非常重要；5）听觉系统（听力）可能具有对侧AEMLR优势。
