Fast Electrical Oscillations in Somatosensory Cortex

体感皮层的快速电振荡

• 批准号: 6724820
• 负责人: DANIEL S. BARTH
• 金额: $ 24.44万
• 依托单位: UNIVERSITY OF COLORADO
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-08-15 至 2007-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6724820
• 关键词: brain electrical activity; brain mapping; electrocorticography; experimental brain lesion; laboratory rat; neural information processing; oscillography; sensory cortex; sensory discrimination; stereotaxic techniques; thalamus; vibrissae

Perhaps the oldest, most widely recognized, and least understood electrical phenomena of the human brain in sickness and in health are its characteristic large amplitude electrical oscillations. Recently, there has been a major advance towards understanding the relationship between oscillations and brain function. Electrocortical oscillations in the gamma bind (approximately 4o Hz), and much higher frequency fast and very fast oscillations (FO and VFO; approximately 300 and 500 Hz, respectively), appear to play a role in temporal coding in sensory cortex. Yet, their functional significance and underlying cellular mechanisms are still a matter of speculation and controversy. In the present experimental series, we address both of these issues by combining in vivo three dimensional extracellular recording with intracellular recording and labeling to study the neural circuitry responsible for generating and propagating fast oscillations in the posteromedial barrel subfield (PMBSF) of rat somatosensory cortex. First, we will extrapolate our results in the auditory system concerning thalamic modulation of cortical gamma oscillations, to the somatosensory system. In so doing, we will establish structural and functional analogies that should strongly support or refute hypotheses about the participation of distinct thalamic systems in the generation or modulation of cortical gamma oscillations, to the somatosensory system. In so doing, we will establish structural and functional analogies that should strongly support or refute hypotheses about the participation of distinct thalamic systems in the generation or modulation of cortical gamma oscillations. Second, we will determine the neural generators of thalamically evoked gamma oscillations in the PMBSF and compare these to our results from intracellular recordings in auditory cortex to evaluate our hypotheses that the generation of cortical gamma oscillations may be based on common cell types in both sensory modalities and not rely on specialized neural pacemakers. Third, we will measure the spatiotemporal response field of single vibrissa stimulation to establish the somatotopic organization and two dimensional shape of stimulus evoked gamma, FO and VFO in the PMBSF and to better anticipate how each oscillatory class could contribute to temporal interactions between adjacent cortical columns. Fourth, we will evaluate possible spatiotemporal interaction patterns of fast oscillations measured at the surface of the PMBSF, evoked by multi-vibrissal stimulation. By looking at how each class of fast oscillations may propagate from multiple start points in the PMBSF and interact in phase sensitive ways within sub-regions of the field, we expect to better understand how these oscillations may encoded the precise timing of sequential transient vibrissal contact with objects and/or how they may synchronize activity in multiple cortical columns when activated by a common and more prolonged stimulus. Finally, we will explore both sub- and suprathreshold events at the intracortical and intracellular level that support temporal integration of each oscillatory class within the PMBSF and histologically label and identify neurons and their processes responsible for this spatio integration.

也许人类大脑在疾病和健康状态下最古老、最广泛认识和最不了解的电现象是其特有的大幅度电振荡。最近，在理解振荡和大脑功能之间的关系方面取得了重大进展。伽马结合中的皮层电振荡（大约 4o Hz）以及频率更高的快速和非常快的振荡（FO 和 VFO；分别大约 300 和 500 Hz）似乎在感觉皮层的时间编码中发挥作用。然而，它们的功能意义和潜在的细胞机制仍然是一个猜测和争议的问题。在本实验系列中，我们通过将体内三维细胞外记录与细胞内记录和标记相结合来解决这两个问题，以研究负责在大鼠体感皮层后内侧桶状子场（PMBSF）中产生和传播快速振荡的神经回路。首先，我们将把听觉系统中丘脑皮质伽马振荡调制的结果外推到体感系统。在此过程中，我们将建立结构和功能类比，这些类比应该强烈支持或反驳关于不同丘脑系统参与皮质伽玛振荡的生成或调节的假设，以及体感系统。在此过程中，我们将建立结构和功能类比，这些类比应该强烈支持或反驳关于不同丘脑系统参与皮质伽玛振荡的生成或调节的假设。其次，我们将确定 PMBSF 中丘脑诱发伽马振荡的神经发生器，并将其与听觉皮层细胞内记录的结果进行比较，以评估我们的假设，即皮质伽马振荡的产生可能基于两种感觉模式中的常见细胞类型，而不依赖于专门的神经起搏器。第三，我们将测量单个触须刺激的时空响应场，以建立 PMBSF 中刺激诱发的伽马、FO 和 VFO 的体位组织和二维形状，并更好地预测每个振荡类别如何促进相邻皮层柱之间的时间相互作用。第四，我们将评估在 PMBSF 表面测量的由多振动刺激引起的快速振荡的可能时空相互作用模式。通过观察每一类快速振荡如何从 PMBSF 中的多个起点传播并在场的子区域内以相敏方式相互作用，我们期望更好地理解这些振荡如何编码与物体的连续瞬时振动接触的精确时间和/或当被常见且更长时间的刺激激活时它们如何同步多个皮层柱中的活动。最后，我们将探索皮质内和细胞内水平的阈下和阈上事件，这些事件支持 PMBSF 内每个振荡类别的时间整合，并在组织学上标记和识别神经元及其负责这种空间整合的过程。