Vuong Quoc C, Shaaban Aya M, Black Carla, Smith Jess, Nassar Mahmoud, Abozied Ahmed, Degenaar Patrick, Al-Atabany Walid
Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom.
Biomedical Engineering Department, Faculty of Engineering, Helwan University, Helwan, Egypt.
Front Neurosci. 2020 Oct 14;14:548030. doi: 10.3389/fnins.2020.548030. eCollection 2020.
The three-dimensional micro-structure of physical surfaces produces frictional forces that provide sensory cues about properties of felt surfaces such as roughness. This tactile information activates somatosensory cortices, and frontal and temporal brain regions. Recent advances in haptic-feedback technologies allow the simulation of surface micro-structures via electro-static friction to produce touch sensations on otherwise flat screens. These sensations may benefit those with visual impairment or blindness. The primary aim of the current study was to test blind and sighted participants' perceptual sensitivity to simulated tactile gratings. A secondary aim was to explore which brain regions were involved in simulated touch to further understand the somatosensory brain network for touch. We used a haptic-feedback touchscreen which simulated tactile gratings using digitally manipulated electro-static friction. In Experiment 1, we compared blind and sighted participants' ability to detect the gratings by touch alone as a function of their spatial frequency (bar width) and intensity. Both blind and sighted participants showed high sensitivity to detect simulated tactile gratings, and their tactile sensitivity functions showed both linear and quadratic dependency on spatial frequency. In Experiment 2, using functional magnetic resonance imaging, we conducted a preliminary investigation to explore whether brain activation to physical vibrations correlated with blindfolded (but sighted) participants' performance with simulated tactile gratings outside the scanner. At the neural level, blindfolded (but sighted) participants' detection performance correlated with brain activation in bi-lateral supplementary motor cortex, left frontal cortex and right occipital cortex. Taken together with previous studies, these results suggest that there are similar perceptual and neural mechanisms for real and simulated touch sensations.
物理表面的三维微观结构会产生摩擦力，这些摩擦力能提供有关所触摸表面属性（如粗糙度）的感官线索。这种触觉信息会激活躯体感觉皮层以及额叶和颞叶脑区。触觉反馈技术的最新进展使得能够通过静摩擦模拟表面微观结构，从而在原本平坦的屏幕上产生触摸感。这些感觉可能会使视力受损或失明者受益。本研究的主要目的是测试盲人和视力正常参与者对模拟触觉光栅的感知敏感度。次要目的是探究哪些脑区参与模拟触摸，以进一步了解触觉的躯体感觉脑网络。我们使用了一种触觉反馈触摸屏，它通过数字操控的静摩擦来模拟触觉光栅。在实验1中，我们比较了盲人和视力正常参与者仅通过触摸检测光栅的能力，这是空间频率（条纹宽度）和强度的函数。盲人和视力正常参与者在检测模拟触觉光栅方面均表现出高敏感度，并且他们的触觉敏感度函数显示出对空间频率的线性和二次依赖性。在实验2中，我们使用功能磁共振成像进行了一项初步研究，以探究对物理振动的脑激活是否与蒙眼（但有视力）参与者在扫描仪外对模拟触觉光栅的表现相关。在神经层面，蒙眼（但有视力）参与者的检测表现与双侧辅助运动皮层、左侧额叶皮层和右侧枕叶皮层的脑激活相关。结合先前的研究，这些结果表明，真实和模拟触摸感觉存在相似的感知和神经机制。
