Functional Modules in Primary Motor Cortex

初级运动皮层的功能模块

• 批准号: 369934445
• 负责人: Professor Dr. Cornelius Schwarz
• 金额: --
• 依托单位: Werner Reichardt-Centrum für integrative Neurowissenschaften (CIN)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/369934445?language=en
• 关键词: Functional; Modules; Primary; Motor; Cortex

Classically it is held that the body's musculature is mapped in a somatotopic fashion across the surface of the motor cortex (somatotopy hypothesis). While a coarse somatotopy is an undeniable fact, finely resolved functional analysis has shown, time and again, and in different species, that the somatotopy is broken on the smaller scale. Moreover, intracortcal micro-stimulation (ICMS) covering long intervals revealed that each point on the motor cortex elicits complex, behaviorally and etiologically relevant movements. This has been interpreted to signify a representation of behavioral functions rather than elemental movements (functional modules hypothesis).Our own previous work in primary whisker motor cortex (vM1) of rodents revealed two areas sharply delineated from each other, and strong candidates for functional, modular organization. Upon ICMS, subarea RW elicits rhythmic whisking, while TZ elicits whisker retraction accompanied by whole body movements. Only TZ, not RW, is a target zone of somatosensory cortex. In this project our aim is to firstly study the causal role of each of the two candidate modules for volitional behavior, needed to decide between the somatotopy and functional module hypotheses. Secondly we aim to work out the behavioral functions and contexts served by these presumptive modules. We will first characterize the connectivity of the candidate modules, expecting to find qualitative different subsets of connections in the case of modules, or orderly shifts of a basic projection pattern across cortex surface in the case of somatotopy. In a second and third objective, integrated within one experiment, we will employ a behavioral task in head-fixed mice, designed to tap into presumed functions of the two candidate modules, and test the respective behavior after permanent lesions and acute deactivations using optogenetic silencing. The task will be comprised of two components, one involving whisking in air (thus testing the presumed function to set control parameters of a known brainstem pattern generator), and the other involving active touch, i.e adaptation of whisks against textures to maximize discrimination. Any differential involvement of the two areas in these different behaviors and sensorimotor contexts would strengthen the functional module hypothesis.

经典的观点认为，身体的肌肉组织以躯体定位的方式映射在运动皮层的表面（躯体定位假说）。虽然一个粗糙的躯体形态是一个不可否认的事实，精细解析的功能分析一次又一次地表明，在不同的物种中，躯体形态在较小的尺度上被打破。此外，覆盖长时间间隔的皮层内微刺激（ICMS）显示，运动皮层上的每个点都激发复杂的、行为上和病因学上相关的运动。这已被解释为表示行为功能，而不是基本的运动（功能模块假说）。我们自己以前的工作在初级须运动皮层（vM1的啮齿动物）揭示了两个领域明显划定彼此，和功能，模块组织的强有力的候选人。在ICMS时，RW区诱发节律性拂动，TZ区诱发伴随全身运动的触须回缩。只有TZ，而不是RW，是躯体感觉皮层的靶区。在这个项目中，我们的目标是首先研究意志行为的两个候选模块中的每一个的因果作用，需要在躯体和功能模块假设之间做出决定。其次，我们的目标是制定出这些假定模块的行为功能和服务的背景。我们将首先描述候选模块的连接性，期望在模块的情况下找到定性的不同连接子集，或者在躯体映射的情况下找到基本投影模式在皮层表面的有序转移。在第二个和第三个目标中，整合在一个实验中，我们将在头部固定的小鼠中采用行为任务，旨在挖掘两个候选模块的假定功能，并使用光遗传学沉默测试永久性病变和急性失活后的相应行为。该任务将由两个部分组成，一个涉及在空气中搅拌（从而测试设定已知脑干模式发生器的控制参数的假定功能），另一个涉及主动触摸，即针对纹理调整搅拌以最大化辨别力。在这些不同的行为和感觉运动背景下，这两个区域的任何差异参与都会加强功能模块假设。