The impact of non-invasive stimulation of the ventromedial prefrontal cortex on attentional biases and reward processing: an advanced network approach

该研究项目的总体目标是阐明腹内侧前额叶皮层（vmPFC）在处理情感材料和奖励方面的主要作用。我们打算把重点放在VMPFC的“工作”，而它的偏见情绪和奖励处理，直接跟踪其激活，但特别是跟踪其功能与其他皮质区的关系。到目前为止，这两种偏见背后的神经机制的证据主要是基于相关方法和对分离的特定大脑区域的分析。相比之下，我们计划直接和非侵入性地调节vmPFC的兴奋性，并计划引入一种新的网络连接方法，使我们能够在神经信息交换过程中跟踪功能性脑回路。我们提出，vmPFC调节其他大脑区域，并通过双向反馈和前馈连接被它们调节。基于现有的文献和德国和波兰研究小组以前的工作，我们预测，注意偏向和奖励加工的神经机制将通过vmPFC和其他脑区之间的动态相互作用来反映，特别是背外侧前额叶和颞顶皮层区域以及与背侧和腹侧注意网络的功能连接。我们将结合联合收割机非侵入性经颅直流电刺激（tDCS）和EEG/MEG方法来增加和降低vmPFC兴奋性并以高时间分辨率监测大脑活动。我们将采用源定位方法，以良好的空间分辨率重建特定大脑结构的激活。重要的是，为了确定注意偏差和奖励处理过程中大脑区域之间的动态关系，将使用定向传递函数（DTF）有效连接进行因果分析，这是一种由波兰小组成功使用并不断开发的创新网络方法。该项目的结果将推进目前对注意偏差和奖励处理的神经基础的理解。特别是，我们的目标是解开这些偏见的动态作用vmPFC。由于情绪注意力和奖励处理中的干扰偏差被认为是包括抑郁症或成瘾在内的各种精神疾病的关键症状，因此该项目的结果将为相应的病理生理学理论提供信息。同时，通过使用DTF，我们将开发一个新的管道来分析源-空间MEG数据。项目的目标和目标只有在两个小组之间的密切合作才能实现。德国小组提供实施MEG-tDCS研究的专门知识，而波兰小组提供传感器和源空间有效连通性分析的专门知识。该联合项目将促进知识和技能的转让，并进一步加强两个小组的合作。

The overarching goal of the proposed research project is to illuminate the presumed cardinal role of the ventromedial prefrontal cortex (vmPFC) on the processing of emotional material and reward. We intend to focus on the vmPFC "at work", while it biases emotional and reward processing, to directly trace its activation but especially trace its functional relationships with other cortical areas. Until now, evidence for the neural mechanisms underlying both types of biases was predominately based on correlational approaches and analyses of particular brain areas in separation. In contrast, we plan to directly and non-invasively modulate vmPFC excitability and plan to introduce a novel network connectivity approach that enables us to track functional brain circuits during exchange of neural information.We propose that the vmPFC modulates other brain regions and gets modulated by them via bidirectional feedback and feedforward connections. Based on the existing literature and previous work of the German and Polish groups, we predict, that neural mechanisms of attentional bias and reward processing will be reflected by a dynamic interaction between vmPFC and other brain areas, specifically dorsolateral prefrontal and temporoparietal cortex regions as well as functional connectivity with the dorsal and ventral attentional networks.In our experiments, we will combine non-invasive transcranial direct-current stimulation (tDCS) with EEG/MEG methodology to increase and decrease vmPFC excitability and monitor brain activity with high temporal resolution. We will employ source localization methods that reconstruct activations of particular brain structures with good spatial resolution. Importantly, to determine dynamic relationships across brain regions during attentional bias and reward processing, causal analyses will be performed using the Directed Transfer Function (DTF) effective connectivity, an innovative network approach which is successfully used and constantly developed by the Polish group.The results of this project will advance current understanding of the neural underpinnings of attentional biases and reward processing. In particular, we aim to unravel the dynamic role of vmPFC during these biases. As disturbed biases in emotional attention and reward processing are considered key symptoms of various psychiatric disorders including depression or addiction, the results of this project will inform theories of corresponding pathophysiology. At the same time, by employing DTF, we will develop a novel pipeline for the analysis of the source-space MEG data.The projects objectives and goals can only be achieved in close collaboration between both groups. The German group provides expertise in implementation of MEG-tDCS studies while the Polish group provides expertise in effective connectivity analyses in sensor and source space. The joint project will enable transfer of knowledge and skills and further strengthen the collaboration of both groups.