Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig 04103, Germany
Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig 04103, Germany.
J Neurosci. 2022 Jan 26;42(4):643-656. doi: 10.1523/JNEUROSCI.0592-21.2021. Epub 2021 Dec 1.
Previous studies have shown that timing of sensory stimulation during the cardiac cycle interacts with perception. Given the natural coupling of respiration and cardiac activity, we investigated here their joint effects on tactile perception. Forty-one healthy female and male human participants reported conscious perception of finger near-threshold electrical pulses (33% null trials) and decision confidence while electrocardiography, respiratory activity, and finger photoplethysmography were recorded. Participants adapted their respiratory cycle to expected stimulus onsets to preferentially occur during late inspiration/early expiration. This closely matched heart rate variation (sinus arrhythmia) across the respiratory cycle such that most frequent stimulation onsets occurred during the period of highest heart rate probably indicating highest alertness and cortical excitability. Tactile detection rate was highest during the first quadrant after expiration onset. Interindividually, stronger respiratory phase-locking to the task was associated with higher detection rates. Regarding the cardiac cycle, we confirmed previous findings that tactile detection rate was higher during diastole than systole and newly specified its minimum at 250-300 ms after the R-peak corresponding to the pulse wave arrival in the finger. Expectation of stimulation induced a transient heart deceleration which was more pronounced for unconfident decision ratings. Interindividually, stronger poststimulus modulations of heart rate were linked to higher detection rates. In summary, we demonstrate how tuning to the respiratory cycle and integration of respiratory-cardiac signals are used to optimize performance of a tactile detection task. Mechanistic studies on perception and cognition tend to focus on the brain neglecting contributions of the body. Here, we investigated how respiration and heartbeat influence tactile perception: respiration phase-locking to expected stimulus onsets corresponds to highest heart rate (and presumably alertness/cortical excitability) and correlates with detection performance. Tactile detection varies across the heart cycle with a minimum when the pulse reaches the finger and a maximum in diastole. Taken together with our previous finding of unchanged early event-related potentials across the cardiac cycle, we conclude that these effects are not a peripheral physiological artifact but a result of cognitive processes that model our body's internal state, make predictions to guide behavior, and might also tune respiration to serve the task.
先前的研究表明，心脏周期内感觉刺激的时间与感知相互作用。鉴于呼吸和心脏活动的自然耦合，我们在这里研究了它们对触觉感知的联合影响。41 名健康的男性和女性参与者报告了手指接近阈电脉冲的意识感知（33%的零试验）和决策信心，同时记录了心电图、呼吸活动和手指光体积描记术。参与者调整呼吸周期以适应预期的刺激开始，以便优先在吸气后期/呼气早期发生。这与整个呼吸周期中的心率变化（窦性心律失常）非常吻合，使得最频繁的刺激开始发生在心率最高的时期，可能表明最高的警觉性和皮质兴奋性。触觉检测率在呼气开始后的第一个象限最高。个体间，对任务的呼吸相位锁定越强，检测率越高。关于心脏周期，我们证实了先前的发现，即舒张期的触觉检测率高于收缩期，并且新指定其最小值在 R 波后 250-300ms，对应于脉搏波到达手指的时间。刺激的预期会引起短暂的心动过缓，对于不确定的决策评级，这种减速更为明显。个体间，刺激后心率的调制越强，检测率越高。总之，我们展示了如何调谐呼吸周期和整合呼吸-心脏信号，以优化触觉检测任务的性能。感知和认知的机制研究往往侧重于大脑，而忽略了身体的贡献。在这里，我们研究了呼吸和心跳如何影响触觉感知：预期刺激开始时的呼吸相位锁定对应于最高心率（推测为警觉性/皮质兴奋性），并与检测性能相关。触觉检测在心脏周期内变化，当脉搏到达手指时达到最小值，在舒张期达到最大值。结合我们先前发现的心脏周期内早期事件相关电位不变，我们得出结论，这些影响不是外周生理伪影的结果，而是认知过程的结果，这些过程模拟了我们身体的内部状态，做出预测以指导行为，并且可能还会调整呼吸以完成任务。
