The human prefrontal cortex (PFC) processes complex sensory information for the elaboration of social behaviors. The non-invasive neuroimaging technique near-infrared spectroscopy (NIRS) identifies hemodynamic changes and concentration of oxygenated (HbO₂) and deoxygenated (HHb) hemoglobin in the cerebral cortex. We studied the responses detected by NIRS in the right and left PFC activation of 28 participants (n = 14 adult young females and males) while processing social/emotional facial expressions, i.e., in conscious perception of different expressions (neutral, happy, sad, angry, disgust, and fearful) and in unconscious/masked perception of negative expressions (fearful and disgust overlapped by neutral). The power spectral analysis from concomitant ECG signals revealed the sympathetic and parasympathetic modulation of cardiac responses. We found higher HbO₂ values in the right PFC of females than in males during, and in the left PFC after, following the conscious perception of the happy face. In males, the left PFC increased and the right PFC decreased HbO₂ while viewing the happy expression. In both sexes, HHb values were higher during the masked presentation of disgust than fearful expression, and after the masked presentation of fearful expression than during it. Higher sympathetic and lower parasympathetic activity (LF/ HF components) occurred in females when consciously and unconsciously processing negative emotions (p < 0.05 in all cases). These results demonstrate that the human PFC displays a selective activation depending on sex, hemispheric laterality, attention, time for responding to conscious and unconscious emotionally loaded stimuli with simulataneous centrally modulated cardiovascular responses.

人类前额叶皮层 (PFC) 处理复杂的感官信息以制定社会行为。非侵入性神经成像技术近红外光谱 (NIRS) 可识别血流动力学变化和氧合浓度 (HbO ₂) 和大脑皮层中的脱氧 (HHb) 血红蛋白。我们研究了 NIRS 在 28 名参与者（n = 14 名成年年轻女性和男性）的右侧和左侧 PFC 激活中检测到的反应，同时处理社交/情感面部表情，即在有意识地感知不同表情（中性、快乐、悲伤、愤怒、厌恶和恐惧）以及对负面表达的无意识/蒙面感知（恐惧和厌恶与中性重叠）。伴随心电图信号的功率谱分析揭示了心脏反应的交感神经和副交感神经调制。我们发现女性右侧 PFC 中的HbO ₂值高于男性，之后在有意识地感知到快乐的脸后，左侧 PFC 中的HbO ₂值高于男性。在男性中，左侧 PFC 增加，右侧 PFC 减少 HbO₂一边看一边开心的表情。在两性中，掩饰厌恶表情期间的 HHb 值高于恐惧表情，掩饰恐惧表情后的 HHb 值高于恐惧表情期间。当有意识和无意识地处理负面情绪时，女性会出现较高的交感神经和较低的副交感神经活动（LF/HF 成分）（在所有情况下，p < 0.05）。这些结果表明，人类 PFC 显示出选择性激活，这取决于性别、半球偏侧性、注意力、响应有意识和无意识情绪负荷刺激的时间，同时中枢调节心血管反应。