Owens Andrew P, Friston Karl J, Low David A, Mathias Christopher J, Critchley Hugo D
Lab of Action & Body, Department of Psychology, Royal Holloway, University of London, Egham, Surrey, UK; Institute of Neurology, University College London, London WC1N 3BG, UK; National Hospital Neurology and Neurosurgery, UCL NHS Trust, London WC1N 3BG, UK.
Wellcome Trust Centre for Neuroimaging, University College London, WC1N 3BG, UK.
Auton Neurosci. 2018 Mar;210:65-71. doi: 10.1016/j.autneu.2018.01.001. Epub 2018 Jan 9.
Predictive coding models, such as the 'free-energy principle' (FEP), have recently been discussed in relation to how interoceptive (afferent visceral feedback) signals update predictions about the state of the body, thereby driving autonomic mediation of homeostasis. This study appealed to 'interoceptive inference', under the FEP, to seek new insights into autonomic (dys)function and brain-body integration by examining the relationship between cardiac interoception and autonomic cardiac control in healthy controls and patients with forms of orthostatic intolerance (OI); to (i) seek empirical support for interoceptive inference and (ii) delineate if this relationship was sensitive to increased interoceptive prediction error in OI patients during head-up tilt (HUT)/symptom provocation. Measures of interoception and heart rate variability (HRV) were recorded whilst supine and during HUT in healthy controls (N = 20), postural tachycardia syndrome (PoTS, N = 20) and vasovagal syncope (VVS, N = 20) patients. Compared to controls, interoceptive accuracy was reduced in both OI groups. Healthy controls' interoceptive sensibility positively correlated with HRV whilst supine. Conversely, both OI groups' interoceptive awareness negatively correlated with HRV during HUT. Our pilot study offers initial support for interoceptive inference and suggests OI cohorts share a central pathophysiology underlying interoceptive deficits expressed across distinct cardiovascular autonomic pathophysiology. From a predictive coding perspective, OI patients' data indicates a failure to attenuate/modulate ascending interoceptive prediction errors, reinforced by the concomitant failure to engage autonomic reflexes during HUT. Our findings offer a potential framework for conceptualising how the human nervous system maintains homeostasis and how both central and autonomic processes are ultimately implicated in dysautonomia.
预测编码模型，如“自由能原理”（FEP），最近在关于内感受（传入内脏反馈）信号如何更新对身体状态的预测从而驱动内稳态的自主调节方面得到了讨论。本研究借助FEP下的“内感受推理”，通过检查健康对照者和体位性不耐受（OI）患者的心脏内感受与自主心脏控制之间的关系，来寻求对自主（功能障碍）功能和脑-体整合的新见解；（i）为内感受推理寻求实证支持，以及（ii）确定这种关系在OI患者头高位倾斜（HUT）/症状激发期间对内感受预测误差增加是否敏感。在健康对照者（N = 20）、体位性心动过速综合征（PoTS，N = 20）和血管迷走性晕厥（VVS，N = 20）患者仰卧位和HUT期间记录内感受和心率变异性（HRV）测量值。与对照者相比，两个OI组的内感受准确性均降低。健康对照者仰卧位时内感受敏感性与HRV呈正相关。相反，两个OI组在HUT期间内感受意识与HRV呈负相关。我们的初步研究为内感受推理提供了初步支持，并表明OI患者群体在不同心血管自主病理生理学中表现出的内感受缺陷背后存在共同的核心病理生理学。从预测编码的角度来看，OI患者的数据表明未能减弱/调节上升的内感受预测误差，同时在HUT期间未能启动自主反射进一步强化了这一点。我们的研究结果为概念化人类神经系统如何维持内稳态以及中枢和自主过程最终如何与自主神经功能障碍相关提供了一个潜在框架。
