Department of Biomedical Engineering, University of Minnesota, 312 Church St. SE, 7-105 Nils Hasselmo Hall, Minneapolis, MN, 55455, United States of America.
Department of Mechanical and Industrial Engineering, University of Minnesota Duluth, 1305 Ordean Court, VKH 105, Duluth, MN, 55812, United States of America.
J Neural Eng. 2022 Jun 23;19(3). doi: 10.1088/1741-2552/ac7665.
. There has been growing interest in understanding multisensory integration in the cortex through activation of multiple sensory and motor pathways to treat brain disorders, such as tinnitus or essential tremors. For tinnitus, previous studies show that combined sound and body stimulation can modulate the auditory pathway and lead to significant improvements in tinnitus symptoms. Considering that tinnitus is a type of chronic auditory pain, bimodal stimulation could potentially alter activity in the somatosensory pathway relevant for treating chronic pain. As an initial step towards that goal, we mapped and characterized neuromodulation effects in the somatosensory cortex (SC) in response to sound and/or electrical stimulation of the body.We first mapped the topographic organization of activity across the SC of ketamine-anesthetized guinea pigs through electrical stimulation of different body locations using subcutaneous needle electrodes or with broadband acoustic stimulation. We then characterized how neural activity in different parts of the SC could be facilitated or suppressed with bimodal stimulation.. The topography in the SC of guinea pigs in response to electrical stimulation of the body aligns consistently to that shown in previous rodent studies. Interestingly, auditory broadband noise stimulation primarily excited SC areas that typically respond to stimulation of lower body locations. Although there was only a small subset of SC locations that were excited by acoustic stimulation alone, all SC recording sites could be altered (facilitated or suppressed) with bimodal stimulation. Furthermore, specific regions of the SC could be modulated by stimulating an appropriate body region combined with broadband noise.. These findings show that bimodal stimulation can excite or modulate firing across a widespread yet targeted population of SC neurons. This approach may provide a non-invasive method for altering or disrupting abnormal firing patterns within certain parts of the SC for chronic pain treatment.
. 人们越来越感兴趣的是通过激活多个感觉和运动通路来理解皮层中的多感觉整合，以治疗大脑疾病，如耳鸣或原发性震颤。对于耳鸣，先前的研究表明，声音和身体的联合刺激可以调节听觉通路，并导致耳鸣症状的显著改善。考虑到耳鸣是一种慢性听觉疼痛，双模态刺激可能会改变与治疗慢性疼痛相关的躯体感觉通路的活动。作为实现这一目标的初步步骤，我们绘制并描述了躯体感觉皮层（SC）中对声音和/或身体电刺激的神经调节效应。我们首先通过使用皮下针电极或宽带声刺激来刺激身体的不同部位，绘制了氯胺酮麻醉豚鼠 SC 中跨 SC 活动的拓扑组织。然后，我们描述了双模态刺激如何促进或抑制 SC 不同部位的神经活动。豚鼠 SC 对身体电刺激的反应中的地形图与先前在啮齿动物研究中显示的地形图一致。有趣的是，听觉宽带噪声刺激主要兴奋通常对下身体部位刺激有反应的 SC 区域。尽管仅有一小部分 SC 位置仅通过声刺激就能被兴奋，但所有 SC 记录部位都可以通过双模态刺激来改变（促进或抑制）。此外，通过刺激适当的身体部位与宽带噪声相结合，可以调节 SC 的特定区域。这些发现表明，双模态刺激可以激发或调节 SC 中广泛但靶向的神经元群体的放电。这种方法可能为改变或破坏 SC 中某些部位的异常放电模式提供一种非侵入性的方法，用于治疗慢性疼痛。
