Functional Imaging Unit, Diagnostic Radiology and Neuroradiology, University of Greifswald, Germany.
Functional Imaging Unit, Diagnostic Radiology and Neuroradiology, University of Greifswald, Germany; AICURA Medical GmbH, Berlin, Germany.
Neuroimage Clin. 2022;35:103093. doi: 10.1016/j.nicl.2022.103093. Epub 2022 Jun 21.
Sensorimotor representations of swallowing in pre- and postcentral gyri of both cerebral hemispheres are interconnected by callosal tracts. We were interested in (1) the callosal location of fibers interconnecting the precentral gyri (with the primary motor cortex; M1) and the postcentral gyri (with the primary somatosensory cortex; S1) relevant for swallowing, and (2) the importance of their integrity given the challenges of swallowing compliance after recovery of dysphagia following stroke. We investigated 17 patients who had almost recovered from dysphagia in the chronic stage following stroke and age-matched and gender-matched healthy controls. We assessed their swallowing compliance, investigating swallowing of a predefined bolus in one swallowing movement in response to a 'go' signal when in a lying position. A somatotopic representation of swallowing was mapped for the pre- and postcentral gyrus, and callosal tract location between these regions was compared to results for healthy participants. We applied multi-directional diffusion-weighted imaging of the brain in patients and matched controls to calculate fractional anisotropy (FA) as a tract integrity marker for M1/S1 callosal fibers. Firstly, interconnecting callosal tract maps were well spatially separated for M1 and S1, but were overlapped for somatotopic differentiation within M1 and S1 in healthy participants' data (HCP: head/face representation; in house dataset: fMRI-swallowing representation in healthy volunteers). Secondly, the FA for both callosal tracts, connecting M1 and S1 swallowing representations, were decreased for patients when compared to healthy volunteers. Thirdly, integrity of callosal fibers interconnecting S1 swallowing representation sites was associated with effective swallowing compliance. We conclude that somatosensory interaction between hemispheres is important for effective swallowing in the case of a demanding task undertaken by stroke survivors with good swallowing outcome from dysphagia.
大脑两半球的中央前回和中央后回中的吞咽感觉运动代表区通过胼胝体束相互连接。我们感兴趣的是：（1）与吞咽相关的连接中央前回（初级运动皮层；M1）和中央后回（初级躯体感觉皮层；S1）的胼胝体纤维的胼胝体位置；（2）鉴于吞咽顺应性在中风后吞咽困难恢复后的挑战，它们完整性的重要性。我们调查了 17 名患者，他们在中风后的慢性阶段几乎从吞咽困难中恢复过来，与年龄和性别匹配的健康对照组进行了比较。我们评估了他们的吞咽顺应性，在仰卧位时通过“开始”信号调查一口预定大小的食团的吞咽情况。在中央前回和中央后回上绘制了吞咽的躯体定位图，并将这些区域之间的胼胝体束位置与健康参与者的结果进行了比较。我们对患者和匹配的对照组进行了大脑多向扩散加权成像，以计算各向异性分数（FA）作为 M1/S1 胼胝体纤维的束完整性标志物。首先，M1 和 S1 的连接胼胝体束图谱在空间上很好地分开，但在健康参与者数据（HCP：头/面部代表；内部数据集：健康志愿者的 fMRI 吞咽代表）中，M1 和 S1 内的躯体定位分化重叠。其次，与健康志愿者相比，连接 M1 和 S1 吞咽代表的两条胼胝体束的 FA 降低。第三，连接 S1 吞咽代表部位的胼胝体纤维的完整性与有效的吞咽顺应性相关。我们的结论是，对于具有良好吞咽结果的中风幸存者完成的具有挑战性任务，大脑半球之间的躯体感觉相互作用对于有效的吞咽很重要。
