Shikha Deep, Ojha Pooja, Shukla Kamla Kant, Bhagat Om Lata, Dixit Abhinav
Department of Physiology, All India Institute of Medical Sciences, New Delhi, Delhi, India.
Department of Physiology, All India Institute of Medical Sciences, Jodhpur, Rajasthan, India.
Ann Neurosci. 2024 Jan 4:09727531231215556. doi: 10.1177/09727531231215556.
Olfactory pathway and limbic system demonstrate a close nexus, which paves common ground for investigating the effects of smell on emotions, cognitive load and autonomic functions. Notably, olfactory stimulation during the administration of cognitive load may interfere with the performance. The study is planned to investigate the effect of citrus inhalation on cognitive performance, through psychophysiological assessments. Thirty male participants were subjected to the cognitive load with the 2-back task in control and experimental sessions. Olfactory stimulation was administered with a pure citrus odour through an aroma diffuser. Electrocardiogram (ECG) for heart rate variability (HRV); photoplethysmography (PPG), and electrodermal activity (EDA) were recorded in experimental and control sessions. Citrus odour significantly improved the performance in 2-back task. A paired t-test revealed that the target correct response numbers and target accuracy were significantly increased with the citrus odour inhalation. The EDA showed a rise in the skin conductance level with the 2-back task that was suppressed with the citrus odour administration. The HRV measures, pNN50, RMSSD, and HF power demonstrated a significant increase in the citrus smell. Importantly, citrus odour produced resilience to cognitive stress due to the cognitive task and it was reflected in the EDA. Olfactory stimulation with citrus improved the scores in the 2-back task performance. Though there was no alteration in the overall variability of cardiac oscillation but there was a conspicuous shift of autonomic balance towards the parasympathetic system with the citrus inhalation. The observed finding advocates the use of citrus odour as a cognitive stress-suppressing measure for cognitive enhancement.
嗅觉通路与边缘系统显示出紧密的联系，这为研究气味对情绪、认知负荷和自主功能的影响奠定了共同基础。值得注意的是，在施加认知负荷期间进行嗅觉刺激可能会干扰表现。本研究计划通过心理生理学评估来探究吸入柑橘气味对认知表现的影响。30名男性参与者在对照和实验环节中接受了2-back任务的认知负荷。通过香薰扩散器给予纯柑橘气味进行嗅觉刺激。在实验和对照环节中记录心电图（ECG）以测量心率变异性（HRV）、光电容积脉搏波描记法（PPG）和皮肤电活动（EDA）。柑橘气味显著提高了2-back任务的表现。配对t检验显示，吸入柑橘气味后目标正确反应数量和目标准确率显著增加。EDA显示，2-back任务期间皮肤电导水平升高，而给予柑橘气味后受到抑制。HRV测量指标，如pNN50、RMSSD和高频功率，在柑橘气味刺激下显著增加。重要的是，柑橘气味对认知任务引起的认知应激产生了恢复力，这在EDA中得到了体现。用柑橘进行嗅觉刺激提高了2-back任务表现的得分。虽然心脏振荡的总体变异性没有改变，但吸入柑橘气味后自主神经平衡明显向副交感神经系统转移。观察结果支持将柑橘气味用作一种减轻认知应激以增强认知的措施。
