SSA: Memories of touch: The role of higher order cortical areas in processing and remembering tactile textures.

人类主要使用视觉系统来理解和解释世界，这使得我们很难想象触觉世界的任何细节或理解其重要性。然而，如果我们无法通过物体的感觉识别物体，那么我们很可能会意识到这种至关重要的感觉所产生的丰富信息。这个学生项目旨在了解纹理信息是如何在大脑中处理的，以及大脑如何适应并学习将意义归因于特定的纹理。为此，我们将研究啮齿动物大脑的纹理处理。啮齿动物是夜间活动的动物，因此高度依赖触觉信息来识别环境中的物体。啮齿动物是触摸方面的专家。在实验室任务中，我们发现它们优先使用胡须来识别不同的纹理。值得注意的是，他们能够区分出颗粒大小仅相差18微米的表面，这一距离比面部胡须之间的间距小一个数量级。2017；2020)，我们建议扩大我们对大脑皮层如何发生高级体感加工的研究。我们通过使用化学遗传学方法在胡须依赖的辨别过程中暂时使初级躯体感觉皮质(SI)失活，从而证实了初级躯体感觉皮质(SI)是自由活动小鼠纹理辨别所必需的。此外，在树突棘的活体2光子显微镜下，我们发现，当且仅当小鼠学习这种辨别时，SI神经元在纹理辨别过程中经历结构突触可塑性。下一步是确定文本信息处理是如何通过假设的腹侧流通路从SI进入海马体的。我们将首先研究SII，它与SI有很强的联系，向周围皮质投射腹侧，并对触觉刺激做出反应。我们将在学习任务中使用DREADDS使SII失活，并测量小鼠是否仍然学习结构辨别。这些研究将有助于理解如何将触觉感觉体验存储为记忆，用于指导未来的选择。

Humans mainly use the visual system to understand and interpret the world, making it difficult for us to imagine theworld of touch in any detail or understand its importance. Yet if we were unable to recognise objects from the waythey feel, we would then most likely realise the wealth of information yielded up by this vital sense. This studentshipproject is aimed at understanding how texture information is processed in the brain and how the brain adapts andlearns to attribute meaning to particular textures. To do this we will study texture processing in the rodent brain.Rodents are nocturnal animals and are therefore highly reliant on tactile information for identifying objects in theirenvironment. Rodents are experts at touch. In laboratory tasks, we have found that they preferentially use theirwhiskers to identify different textures. Remarkably, they are able to distinguish between surfaces that differ in particlesize by just 18um, a distance that is orders of magnitude smaller than the spacing between whiskers on the face.Building on the findings of an earlier BBSRC PhD studentship (Pacchiarin et al. 2017; 2020), we propose to extend ourinvestigation of how higher order somatosensory processing occurs in the cerebral cortex. We have established thatprimary somatosensory cortex (SI) is necessary for texture discrimination in freely moving mice by using chemo-genetic methods to inactivate temporarily SI during a whisker-dependent discrimination. Furthermore, using in vivo2-photon microscopy of dendritic spines, we have found that SI neurones undergo structural synaptic plasticity duringtexture discrimination, if and only if the mice learn the discrimination. The next step is to determine how textureinformation processing proceeds from SI to the hippocampus via the hypothesised ventral stream pathway. We willinitially study SII, which is strongly connected to SI, projects ventrally to Perirhinal cortex, and responds to tactiletextures. We will inactivate SII during the learning task using DREADDs and measure whether the mice still learn thetexture discrimination. These studies will lead to an understanding of how tactile sensory experience can be stored asmemories that are used to direct future choices.