Laser Speckled Contrast Imaging to measure blood flow to microvasculature

* 皮肤机械感受器的激活调节上肢和下肢的肌肉活动以调节运动。选择机械感受器类别，特别是快速适应（FAI），与运动神经元有很强的耦合，表明它们在平衡控制中发挥重要作用。Bent博士工作的最新进展揭示了血流和皮肤传入放电模式之间关系的潜在混杂因素。在显微神经摄影的单个单元记录期间，足底的冷却显示了皮肤传入神经响应于负荷的行为的显著变化，这些变化被认为与血流的调制有关。据称，血流改变皮肤特性，包括血管诱导的皮肤硬度，以及影响机械感受器本身的机械特性。外力到机械感受器末端器官的传导受到皮肤环境的这些机械性质（包括硬度和刚度）的影响，导致传入神经放电的能力改变。这会影响负荷转化为传入放电的能力，并导致运动控制的缺陷。因此，不仅传入输入的数量，而且传入输入的质量随着可变的血流而改变。** 血流对于了解中枢致敏背后的机制也至关重要。中枢敏感化（CS）是神经系统的一种适应不良状态，对骨骼肌的结构和功能有重要影响。虽然疼痛无处不在，但我们目前还不了解导致肌肉症状表现的机制，例如导致功能改变的触发点。Srbely博士的研究计划的目的是探索CS与肌肉功能的时间和剂量反应关系。然而，为了评估CS的变化，必须能够测量它。传统上使用主观测量，这限制了量化变化的能力。为了解决这一知识差距，Srbely博士需要一种能够客观测量中枢致敏变化的工具，这将使未来的工作能够推进和评估剂量依赖性反应和干预措施。对疼痛的自主神经反应改变血流，并且是使外周皮肤微血管灌注能够用作CS的可行客观生物标志物的机制。这将通过量化脊柱水平的疼痛来实现该领域的重大进步。** 这项拨款提案是为了申请资金购买一台能够测量毛细血管血流的激光散斑对比成像（LSCI）相机。这些设备将直接支持两个NSERC资助的研究项目，目前培训了20名HQP。采购相机将大大增加HQP在各级培训中的机会，并通过提供多层调查（血管，神经，全身）来扩大制定高质量研究目标的能力。

***Activation of cutaneous mechanoreceptors modulates muscle activity in the upper and lower limbs to regulate movement. Select mechanoreceptor classes, in particular Fast Adapting (FAI), have strong coupling to motor neurones suggesting they have a large role in balance control. Recent advancements in Dr. Bent's work have revealed potential confounding factors in the relationship between blood flow and cutaneous afferent firing patterns. During single unit recordings in microneurography, cooling of the foot sole has shown significant changes in the behaviour of cutaneous afferents in response to load, changes believed to relate to modulation of blood flow. Blood flow purportedly changes skin properties, including vascular induced skin stiffness, as well as impacting the mechanical properties of the mechanoreceptors themselves. Transduction of external forces to the mechanoreceptor end organ is impacted by these mechanical properties of the skin environment, including hardness and stiffness, resulting in altered capability of the afferents to discharge. This affects the ability of load to translate into afferent firing, and results in deficits in movement control. As such, not only the quantity, but the quality of the afferent input is altered with variable blood flow. ******Blood flow is also critical to understand mechanisms behind central sensitization. Central Sensitization (CS) is a maladaptive state of the nervous system with significant implications to skeletal muscle structure and function. While pain is ubiquitous, we do not currently understand the mechanisms that lead to manifestation of symptoms in muscle, such as trigger points, which lead to altered function. The objective of Dr. Srbely's research program is to explore both the temporal and dose-response relationship of CS with muscle function. However, to assess changes in CS, it is necessary to be able to measure it. Traditionally subjective measures have been used, which limit the ability to quantify change. To address this knowledge gap Dr. Srbely requires a tool able to objectively measure changes in central sensitization, which will allow future work to push forward and evaluate dose dependent responses and interventions. Autonomic responses to pain alter blood flow and are mechanisms that will enable the use of peripheral cutaneous microvascular perfusion as a viable objective biomarker for CS. This will allow significant advancements in the field by quantifying pain at the spinal level. ******This grant proposal is to request funds for the purchase of a Laser Speckle Contrast Imaging (LSCI) Camera capable of measuring blood flow to capillaries. The equipment will directly support two NSERC funded research programs, which currently train 20 HQP. Procurement of the camera will vastly increase the opportunities for HQP across all levels of training and expand the capacity to develop high quality research goals by providing multiple tiers of investigation (vascular, nerve, whole body).*****