Organization and Development of Sensory Systems and Emotions

根据过去的专门知识和成就，本项目有三个主要主题。第一部分考察了感觉系统和多感觉整合。视觉-触觉刺激的多感觉整合将着眼于不同半空间内或跨不同半球的整合，以研究当一起呈现而不是单独呈现时对表现的促进作用。当刺激呈现在不同的半空间时，特别令人感兴趣的是CC如何促进整合。这是通过比较神经典型和CC切片或发育不全的受试者来实现的。对行为结果的解释将使用功能磁共振成像进行验证。还将研究植入颅内脑电电极(IEEG)的患者的视觉和听觉处理，以及当刺激直接或通过大脑间通路，即胼胝体(CC)时，视觉对象识别时神经元如何结合。特别令人感兴趣的是阿尔法和伽马波，以及较高水平的皮质区域如何通过自上而下的促进作用促进识别，以及当复杂刺激第二次出现在半球内或半球间时，这一点。对于在不同识别水平上呈现的听觉刺激，也就是当复杂的刺激(铃声、声音)以不同的信噪比呈现时，将检查类似的过程。第二个主题将考察情绪过程。因此，我们将研究当情绪负载刺激呈现在分辨率较高但传输时间较慢的中央视觉中时，外围视网膜呈现的情绪视觉刺激是如何影响识别的。为了进一步验证我们的假设，还将使用正常和修改的空间分辨率对刺激进行调制和呈现。我们还将研究不同唤醒(强烈、中性)和效价(积极、消极、中性)值的情绪刺激的大脑半球专门化。实际上，对于觉醒，似乎有一个右半球优势(纹状体-边缘区域)，但在中央凹出现时，有一个左眶-额区，用于识别。这些研究将使用行为评估(认出时的反应时间)、电生理测量(皮肤电导反应-SCR)和脑磁图成像。我们还将在植入患者中使用我们的iEEG范式来检查上述次级主题。这些患者还将接受疼痛同理心的测试，即他们在大脑皮层水平上理解和体验他人情感和需求的能力。因此，患者必须识别演员表达的疼痛，我们检查他们的大脑皮层反应。另一个子主题是情绪化决策，当受试者必须处理风险和安全条件才能赢钱或输钱时。在这两种情况下，岛叶皮质是感兴趣的目标区域。我们应该特别注意镜像神经元系统，也就是说，无论他们经历或观察到他人的同理心或危险决策，神经元的反应都是相似的。最后，我们最近验证了可行性的一个新主题将检查在这些患者中如何在单细胞水平上处理上述刺激(例如，复杂图像的视觉处理、情绪面部识别)。考虑到记录患者单细胞反应的限制，我们仍在掌握该技术的所有组件的过程中，因此提出的具体项目很少。然而，我们有信心我们将有效地进行这项工作，因为我们最近在一名患者的枕下回记录到四个神经元，其中一个神经元对高兴或愤怒的面孔表现出不同的激活。这些结果预示着令人兴奋的可能性。

The present project has three principal themes based on past expertise and accomplishments. The first examines sensory system and multi-sensory integration. Multisensory integration of visuo-tactile stimuli will look at integration within or across different hemispaces to study the facilitation of performance when presented together instead of separately. Of particular interest when stimuli are presented in different hemispaces is how the CC contributes to integration. This is achieved by comparing neurotypical and CC sectioned or agenesis subjects. The interpretations of the behavioral results will be validated using fMRI imaging. Visual and auditory processing will also be examined in patients implanted with intracranial EEG electrodes (iEEG) and how neuronal binding at visual object recognition is achieved when stimuli are presented directly to one or via the inter-hemispheric pathway, namely the corpus callosum (CC). Of particular interest are the alpha and gamma waves and how higher level cortical areas facilitate recognition through top-down facilitation, and this for complex stimuli when they are presented intra- or inter-hemispherically for a second time. Similar processes will be examined for auditory stimuli presented at different levels of recognition, that is, when complex stimuli (bells, voices) are presented at different signal to noise ratios. The second theme will examine emotional processing. Thus, we shall examine how emotional visual stimuli presented in peripheral retina, which has poor spatial resolution but transmits rapidly to visual areas, influences recognition when emotionally laden stimuli are presented in central vision, which has high resolution but slower transmission time. To further validate our hypothesis, stimuli will also be modulated and presented using normal and modified spatial resolution. We shall also examine the hemispheric specialization for emotional stimuli of different arousal (strong, neutral) and valence (positive negative, neutral) values. In effect, there appears to be a right hemispheric dominance (striato-limbic areas) for arousal but a left orbito-frontal one for recognition at foveal presentation. These studies will use behavioral assessments (reaction time at recognition), electrophysiological measures (skin conductance response- SCR) and MEG imaging. We shall also examine the above sub-themes using our iEEG paradigm in implanted patients. These patients will also be tested on empathy for pain, namely, their capacity at the cortical level to understand and experience other's emotional feelings and needs. Thus the patient has to recognize the pain expressed by an actor and we examine their cortical responses. Another sub-theme is emotional decison making when a subject has to treat risky and safe conditions to win or loose money. In both, the insular cortex is the target region of interest. We shall pay particular attention to the mirror neuron system, that is, neurons that react similarly whether they experience or observe empathy or risky decision making in others. Finally, a new theme for which we have recently validated the feasibility will examine how the stimuli presented above (e.g., visual treatment of complex images, emotional face recognition) are treated at the single-cell level in these patients. Few specific projects are presented since we are still in the process of mastering all the components of the technique given the constraints of recording in patients single-cell responses. However, we are confident that we shall carry this out effectively since we have recently recorded four neurons in one patient in the inferior occipital gyrus, including one neuron that showed differential activations to happy or angry faces. These results promise exciting possibilities.