Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology, 3 Pasteur St., 02093 Warsaw, Poland.
J Neurosci Methods. 2013 Feb 15;213(1):32-8. doi: 10.1016/j.jneumeth.2012.12.002. Epub 2012 Dec 14.
Neural correlates of Braille reading have been widely studied with different neuroimaging techniques. Nevertheless, the exact brain processes underlying this unique activity are still unknown, due to suboptimal accuracy of imaging and/or stimuli delivery methods. To study somatosensory perception effectively, the stimulation must reflect parameters of the natural stimulus and must be applied with precise timing. In functional magnetic resonance imaging (fMRI) providing these characteristics requires technologically advanced solutions and there have been several successful direct tactile stimulation devices designed that allow investigation of somatotopic organization of brain sensory areas. They may, however, be of limited applicability in studying brain mechanisms related to such distinctive tactile activity as Braille reading. In this paper we describe the design and experimental evaluation of an innovative MRI-compatible Braille Character Stimulator (BCS) enabling precise and stable delivery of standardized Braille characters with high temporal resolution. Our device is fully programmable, flexible in stimuli delivery and can be easily implemented in any research unit. The Braille Character Stimulator was tested with a same-different discrimination task on Braille characters during an event-related fMRI experiment in eleven right-handed sighted adult subjects. The results show significant activations in several cortical areas, including bilateral primary (SI) and secondary somatosensory (SII) cortices, bilateral premotor and supplementary motor areas, inferior frontal gyri, inferior temporal gyri and precuneus, as well as contralateral (to the stimulated hand) thalamus. The results validate the use of the BCS as a method of effective stimuli application in fMRI studies, in both sighted and visually impaired subjects.
神经影像学技术广泛研究了盲文阅读的神经相关性。然而，由于成像和/或刺激传递方法的准确性不高，这种独特活动背后的确切大脑过程仍然未知。为了有效地研究体感知觉，刺激必须反映自然刺激的参数，并且必须具有精确的定时。在功能磁共振成像（fMRI）中提供这些特征需要技术先进的解决方案，已经设计出几种成功的直接触觉刺激设备，允许研究大脑感觉区域的躯体定位组织。然而，它们在研究与盲文阅读等独特触觉活动相关的大脑机制方面可能具有有限的适用性。本文描述了一种创新的 MRI 兼容盲文字符刺激器（BCS）的设计和实验评估，该刺激器能够以高精度和高时间分辨率精确稳定地传递标准化的盲文字符。我们的设备完全可编程，刺激传递灵活，可以很容易地在任何研究单位实施。盲文字符刺激器在 11 名右利手视力正常的成年受试者进行事件相关 fMRI 实验期间的盲文字符相同-不同判别任务中进行了测试。结果显示，在几个皮质区域中出现了显著的激活，包括双侧初级（SI）和次级体感（SII）皮质、双侧运动前区和辅助运动区、下额回、下颞回和楔前叶，以及对侧（受刺激手）丘脑。结果验证了 BCS 作为 fMRI 研究中有效刺激应用方法的使用，无论是在视力正常的受试者还是视力受损的受试者中。
