Somatosensory-to-auditory cross-modal plasticity in cochlear implanted children

描述（由申请人提供）：神经科学的一个共同原则是，缺乏刺激的大脑具有重组的能力和趋势。也就是说，完整的感觉模态（例如，听觉、视觉）可以重新激活被剥夺的通道的皮层--称为跨通道重组。一种自然发生的感觉剥夺形式，其中跨通道重组已被证明是耳聋。事实上，几项研究已经在动物和人类身上证明了令人信服的证据，即视觉系统可以在耳聋时招募听觉皮层。相反，相对较少的研究表明，听觉皮层的躯体感觉系统在聋人动物和人类的跨模态招聘。 耳蜗植入体（CI）是通过电刺激VIII神经为听觉系统提供声音通路的器械。这些设备已被证明对许多聋人和儿童有益，许多人达到了高水平的行为熟练度（例如，言语感知）。另一方面，有些孩子在CI方面并不成功。此外，植入年龄、设备编程和使用一致性等因素只能解释CI儿童行为表现的一些变化。然而，最近的研究表明，在这些人的行为表现与CI的成年人所表现出的视觉和听觉系统之间的跨模态重组的程度。由于发育中的大脑具有高度的可塑性，并且由于跨模态重组似乎对行为结果有影响，因此有理由相信跨模态重组可能会发生并对CI儿童的功能表现产生负面影响。 据我们所知，没有研究已经做了调查躯体感觉听觉（SS-A）跨模态重组与CI儿童。然而，由于体感和听觉系统对几乎相同的物理现象（即，振荡形式的机械压力），这是非常合理的SS-A交叉模式重组可能发生在一个剥夺的系统。也就是说，听觉系统已经准备好处理躯体感觉刺激，在皮层的某些区域甚至比视觉刺激更容易处理。如果SS-A跨模态重组发生在CI儿童中，可能会对他们的行为表现产生不利影响。因此，我们提出了一项研究，具有以下目的：1）使用高密度脑电图检查耳蜗植入儿童的体感-听觉跨通道重组; 2）检查耳蜗植入儿童的体感-听觉跨通道重组与功能表现（言语感知）之间的关系。我们假设，高密度脑电图和电流源重建的皮层活动将揭示SS-A跨模态重组与CI儿童，这些发现将与这些儿童的行为结果呈负相关。了解并能够利用脑梗死儿童的皮质可塑性不仅是神经科学研究的一个最近的焦点，而且也代表了一个有价值的奋进，可能会导致改善这些患者的临床治疗和管理。

DESCRIPTION (provided by applicant): A common tenet of neuroscience is that a brain deprived of stimulation has the ability and tendency to re-organize. That is, intact sensory modalities (e.g., hearing, vision) can recruit the cortices of deprived modalities-known as cross-modal re-organization. A naturally occurring form of sensory deprivation in which cross-modal re-organization has been shown to occur is deafness. In fact, several studies have demonstrated convincing evidence in both animals and humans that the visual system can recruit the auditory cortex in deafness. In contrast, relatively few investigations have shown cross-modal recruitment of the auditory cortex by the somatosensory system in deaf animals and humans. Cochlear implants (CI) are devices that provide access to sound for the auditory system by electrically stimulating the VIII nerve. These devices have proven to be beneficial to many deaf adults and children, with many achieving high levels of behavioral proficiency (e.g., speech perception). On the other hand, some children do not have a great deal of success with CIs. Furthermore, factors such as age of implantation, device programming, and consistency of use have only been able to explain some of the variation in behavioral performance in CI children. However, recent studies have revealed that the degree of cross-modal re-organization between the visual and auditory systems exhibited by adults with CIs is correlated with behavioral performance in these individuals. Due to the high degree of plasticity in the developing brain and because cross-modal re-organization appears to have bearing on behavioral outcomes, it is reasonable to believe that cross-modal re-organization could occur and negatively affect functional performance in children with CIs. No study, to our knowledge, has been done to investigate somatosensory-to-auditory (SS-A) cross-modal re-organization in children with CIs. However, because the somatosensory and auditory systems are responsive to virtually the same physical phenomena (i.e., mechanical pressure in the form of oscillations) in overlapping frequency ranges, it is highly plausible that SS-A cross-modal re-organization could occur in an auditorily deprived system. That is, the auditory system is primed to process somatosensory stimuli, maybe even more so than visual stimuli in some areas of the cortex. If SS-A cross-modal re-organization is occurring in CI children, it may be adversely affecting their behavioral performance. Thus, we propose a study with the following aims: 1) To examine somatosensory-to-auditory cross-modal reorganization using high-density EEG in children with cochlear implants; 2) To examine the relationship between somatosensory-to-auditory cross-modal re-organization and functional performance (speech perception) in children with cochlear implants. We hypothesize that high-density EEG and current source reconstruction of cortical activity will reveal SS-A cross-modal re- organization in children with CIs, and that these findings will be negatively correlated with behavioral outcome in these children. Understanding and being able to harness cortical plasticity in children with CIs is not only a recent focus of neuroscientific research, but also represents a worthy endeavor that could lead to improved clinical treatment and management for these patients.