Proverbio A M, Pischedda F
Laboratory of Cognitive Electrophysiology, Department of Psychology, University of Milano-Bicocca, Milan, Italy.
Front Hum Neurosci. 2023 Mar 15;17:1146789. doi: 10.3389/fnhum.2023.1146789. eCollection 2023.
While EEG signals reflecting motor and perceptual imagery are effectively used in brain computer interface (BCI) contexts, little is known about possible indices of motivational states. In the present study, electrophysiological markers of imagined motivational states, such as craves and desires were investigated.
Event-related potentials (ERPs) were recorded in 31 participants during perception and imagery elicited by the presentation of 360 pictograms. Twelve micro-categories of needs, subdivided into four macro-categories, were considered as most relevant for a possible BCI usage, namely: primary visceral needs (e.g., hunger, linked to desire of food); somatosensory thermal and pain sensations (e.g., cold, linked to desire of warm), affective states (e.g., fear: linked to desire of reassurance) and secondary needs (e.g., desire to exercise or listen to music). Anterior N400 and centroparietal late positive potential (LPP) were measured and statistically analyzed.
N400 and LPP were differentially sensitive to the various volition stats, depending on their sensory, emotional and motivational poignancy. N400 was larger to imagined positive appetitive states (e.g., play, cheerfulness) than negative ones (sadness or fear). In addition, N400 was of greater amplitude during imagery of thermal and nociceptive sensations than other motivational or visceral states. Source reconstruction of electromagnetic dipoles showed the activation of sensorimotor areas and cerebellum for movement imagery, and of auditory and superior frontal areas for music imagery.
Overall, ERPs were smaller and more anteriorly distributed during imagery than perception, but showed some similarity in terms of lateralization, distribution, and category response, thus indicating some overlap in neural processing, as also demonstrated by correlation analyses. In general, anterior frontal N400 provided clear markers of subjects' physiological needs and motivational states, especially cold, pain, and fear (but also sadness, the urgency to move, etc.), than can signal life-threatening conditions. It is concluded that ERP markers might potentially allow the reconstruction of mental representations related to various motivational states through BCI systems.
虽然反映运动和感知想象的脑电图信号在脑机接口（BCI）环境中得到了有效应用，但对于动机状态的可能指标却知之甚少。在本研究中，对诸如渴望和欲望等想象的动机状态的电生理标记物进行了研究。
在31名参与者观看360个象形图引发的感知和想象过程中记录事件相关电位（ERP）。将12个微观需求类别细分为4个宏观类别，认为这些类别与可能的BCI使用最为相关，即：主要内脏需求（如饥饿，与对食物的渴望有关）；体感热觉和痛觉（如寒冷，与对温暖的渴望有关）、情感状态（如恐惧：与对安心的渴望有关）和次要需求（如锻炼或听音乐的欲望）。测量并统计分析了前部N400和中央顶叶晚期正电位（LPP）。
N400和LPP对各种意志状态的敏感性不同，这取决于它们的感觉、情感和动机强度。与消极状态（悲伤或恐惧）相比，N400对想象的积极食欲状态（如玩耍、快乐）更大。此外，在热觉和伤害性感觉的想象过程中，N400的振幅比其他动机或内脏状态时更大。电磁偶极子的源重建显示，运动想象时感觉运动区域和小脑被激活，音乐想象时听觉和额上区域被激活。
总体而言，ERP在想象过程中比感知过程更小且分布更靠前，但在偏侧化、分布和类别反应方面表现出一些相似性，因此表明神经处理存在一些重叠，相关性分析也证明了这一点。一般来说，前额部N400为受试者的生理需求和动机状态提供了清晰的标记，尤其是寒冷、疼痛和恐惧（还有悲伤、运动的紧迫性等），这些可能预示着危及生命的状况。得出的结论是，ERP标记物可能潜在地允许通过BCI系统重建与各种动机状态相关的心理表征。
