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Identifying heart-brain interactions during internally and externally operative attention using conditional entropy

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Abstract

Heart and brain interactions mediate human cognition. This investigation identifies heart-brain interactions during internally operative attention (AI) and externally operative attention (AE). AI attention involves short term memory, whereas AE attention deals with automatic and transient response to objects in the external world. A modified Posner’s spatial orienting task used to differentiate AI and AE attention. Heart and brain rhythms recorded in fourteen healthy participants. Functional coupling from heart-to-brain (Cheart→brain) and brain-to-heart (Cbrain→heart) time series derived using an information domain approach based on conditional entropy. The experimental results showed that low-frequency power of heart rate variability (HRV-LF) and sympathovagal balance (LF/HF ratio) during AE significantly increased compared with that for AI. Furthermore, the information flow from heart-to-brain increased and decreased form brain-to-heart during AE as compared to AI. Also, opposite trend in relationship noted between coupling index (Ci→j) and HRV-LF during AI and AE attention. The conditional entropy technique enabled simultaneous analysis of heart-brain rhythms to identify heart-brain interactions during AI and AE attention.

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... The early-stage detection of cardiac arrhythmia is of prime importance [1]. But during the acquisition of ECG data, different types of noise gets involved, which hide its important characteristics that mislead its analysis and introduces the non-linearity [38,39]. Analysis of this nonlinear signal requires automated analysis as provided by computer-aided diagnosis (CAD). ...
... In this paper, 12 real-time recordings (RT DB) were also used to establish the performance of the proposed methodology in a practical scenario. The use of two databases in this paper is in line with other studies in the existing literature that made use of variety of databases for validating their work [39,[72][73][74][75]. ...
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We propose that voluntary and involuntary attention affect different mechanisms and have different consequences for performance measured in reaction time. Voluntary attention enhances the perceptual representation whereas involuntary attention affects the tendency to respond to stimuli in one location or another. In a spatial-cueing paradigm, we manipulated perceptual difficulty and compared voluntary and involuntary attention. For the voluntary-attention condition, the spatial cue was predictive of the target location, whereas in the involuntary-attention condition it was not. Increasing perceptual difficulty increased the attention effect with voluntary attention, but decreased it with involuntary attention. Thus voluntary and involuntary attention have different consequences when perceptual difficulty is manipulated and hence are probably caused by different mechanisms.
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This study employed a paired stimulus paradigm to compare phasic changes in heart rate among children (age categories 6-8, 9-10, and 11-12) and adults (age categories 18-19 and 20-22) with attention-deficit/hyperactivity disorder (ADHD) and age-matched controls. A sample of 95 participants (19 ADHD-diagnosed children, 34 controls, 20 ADHD-diagnosed adults, and 22 controls) solved a planning task, the Tower of London, through 4 levels of difficulty. It was hypothesized that groups with ADHD would show greater heart rate acceleration and less final deceleration than would controls, and that these heart rate responses would change with age and difficulty level as well. Though heart rate differences were found among age categories and difficulty levels, none were found between participants with ADHD and controls. The lack of ADHD differences are not consistent with the behavioral evidence that planning by itself is one of the marked executive function deficits in ADHD. Because ADHD differences were not evident, the effects either were not present or were smaller than that of difficulty level and age. Possible explanations for this lack of difference and future directions are discussed.
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In the present paper, we describe a model of neurovisceral integration in which a set of neural structures involved in cognitive, affective, and autonomic regulation are related to heart rate variability (HRV) and cognitive performance. We detail the pathways involved in the neural regulation of the cardiovascular system and provide pharmacological and neuroimaging data in support of the neural structures linking the central nervous system to HRV in humans. We review a number of studies from our group showing that individual differences in HRV are related to performance on tasks associated with executive function and prefrontal cortical activity. These studies include comparisons of executive- and nonexecutive-function tasks in healthy participants, in both threatening and nonthreatening conditions. In addition, we show that manipulating resting HRV levels is associated with changes in performance on executive-function tasks. We also examine the relationship between HRV and cognitive performance in ecologically valid situations using a police shooting simulation and a naval navigation simulation. Finally, we review our studies in anxiety patients, as well as studies examining psychopathy. These findings in total suggest an important relationship among cognitive performance, HRV, and prefrontal neural function that has important implications for both physical and mental health. Future studies are needed to determine exactly which executive functions are associated with individual differences in HRV in a wider range of situations and populations.
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The cerebral cortex had massive bidirectional connections to autonomic nervous system and mental performance can induce change of autonomic activity, but which regions are related to autonomic function is not clear. The study was to analyze the scalp positions which may affect cardiac autonomic nervous activity during a mental arithmetic (MA) task. Forty-three healthy male subjects were voluntarily participated in the study. Sympathetic and parasympathetic activities were estimated with heart rate variability. Scalp potential was determined by the wavelet packet parameters and approximate entropy (ApEn) of Electroencephalogram (EEG). The results showed that heart rate and the normalized low frequency power component were significantly increased (p<0.01) and the high frequency power component was decreased (p<0.01). Meanwhile relative wavelet packet energy in alpha band of EEG at P3, P4, Pz, O1, O2 and Oz electrodes were decreased and the beta band of EEG at the same electrodes were increased significantly (p<0.01). ApEn was significantly increased in MA (p<0.01). Moreover, changes of brain activity were earlier than the changes of autonomic activity and significantly correlations existed between heart rate variability and wavelet packet energy (p<0.05). In addition, a significant positive correlation between HR change and the laterality ratio score of alpha band in P3 v P4 (p<0.05) were observed. It is noted that cerebral conscious activity enhanced with the decrease of parasympathetic activity and increase of sympathetic activity, and the right post-central areas dominated sympathetic activity during stress-inducing mental tasks.
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The neural regulation of circulatory function is mainly effected through the interplay of the sympathetic and vagal outflows. This interaction can be explored by assessing cardiovascular rhythmicity with appropriate spectral methodologies. Spectral analysis of cardiovascular signal variability, and in particular of RR period (heart rate variability, HRV), is a widely used procedure to investigate autonomic cardiovascular control and/or target function impairment. The oscillatory pattern which characterizes the spectral profile of heart rate and arterial pressure short-term variability consists of two major components, at low (LF, 0.04-0.15Hz) and high (HF, synchronous with respiratory rate) frequency, respectively, related to vasomotor and respiratory activity. With this procedure the state of sympathovagal balance modulating sinus node pacemaker activity can be quantified in a variety of physiological and pathophysiological conditions. Changes in sympathovagal balance can be often detected in basal conditions, however a reduced responsiveness to an excitatory stimulus is the most common feature that characterizes numerous pathophysiological states. Moreover the attenuation of an oscillatory pattern or its impaired responsiveness to a given stimulus can also reflect an altered target function and thus can furnish interesting prognostic markers. The dynamic assessment of these autonomic changes may provide crucial diagnostic, therapeutic and prognostic information, not only in relation to cardiovascular, but also non-cardiovascular disease. As linear methodologies fail to provide significant information in conditions of extremely reduced variability (e.g. strenuous exercise, heart failure) and in presence of rapid and transients changes or coactivation of the two branches of autonomic nervous system, the development of new non-linear approaches seems to provide a new perspective in investigating neural control of cardiovascular system.
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In recent years, several attempts have been made to characterize the nature of the cognitive deficits shown by patients with Parkinson's disease. It has been suggested variously that they have difficulty in switching cognitive set, in performing effortful (or controlled) as opposed to automatic tasks, or that their impairment is found in tasks which maximize the amount of 'self-directed task specific planning'. It is proposed that this latter distinction may be reformulated in terms of the degree of internal versus external attentional control which is required by the task. An experiment is described which attempted to manipulate this parameter. A version of the Stroop colour-word test was used, in which the words 'red' and 'green' were presented in the complementary coloured 'ink'. Subjects responded either to the colour of the ink in which the word was written or the colour named by the word. The relevant attribute changed at intervals during the course of the experiment. In one condition, the relevant stimulus attribute was cued before each trial. In another condition, subjects had to remember which attribute was currently relevant. Results revealed that patients with Parkinson's disease were impaired mainly on the second version of the task which required internal attentional control. The results are discussed in relation to the models of Working Memory (Baddeley, 1986), and attentional control (Norman and Shallice, 1980). Exploration of these models leads to the formulation of a theory in which the crucial determinant of cognitive impairment in Parkinson's disease is reduced resources in the Supervisory Attentional System. Provided the demands of the task are within the patient's available attentional resources the patient may not show any deficit. If, however, the attentional demands exceed available resources, as in tasks which depend upon internal cues, then deficits will be observed.
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In the present paper we present the outlines of a model that integrates autonomic, attentional, and affective systems into a functional and structural network that may help to guide us in our understanding of emotion regulation and dysregulation. We will emphasize the relationship between attentional regulation and affective processes and propose a group of underlying physiological systems that serve to integrate these functions in the service of self-regulation and adaptability of the organism. We will attempt to place this network in the context of dynamical systems models which involve feedback and feedforward circuits with special attention to negative feedback mechanisms, inhibitory processes, and their role in response selection. From a systems perspective, inhibitory processes can be viewed as negative feedback circuits that allow for the interruption of ongoing behavior and the re-deployment of resources to other tasks. When these negative feedback mechanisms are compromised, positive feedback loops may develop as a result (of dis-inhibition). From this perspective, the relative sympathetic activation seen in anxiety disorders may represent dis-inhibition due to faulty inhibitory mechanisms.
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The aim of the present study was to investigate the effect of vagal tone on performance during executive and non-executive tasks, using a working memory and a sustained attention test. Reactivity to cognitive tasks was also investigated using heart rate (HR) and heart rate variability (HRV). Fifty-three male sailors from the Royal Norwegian Navy participated in this study. Inter-beat-intervals were recorded continuously for 5 min of baseline, followed by randomized presentation of a working memory test (WMT) based on Baddeley and Hitch's research (1974) and a continuous performance test (CPT). The session ended with a 5-min recovery period. High HRV and low HRV groups were formed based on a median split of the root mean squared successive differences during baseline. The results showed that the high HRV group showed more correct responses than the low HRV group on the WMT. Furthermore, the high HRV group showed faster mean reaction time (mRT), more correct responses and less error, than the low HRV group on the CPT. Follow-up analysis revealed that this was evident only for components of the CPT where executive functions were involved. The analyses of reactivity showed a suppression of HRV and an increase in HR during presentation of cognitive tasks compared to recovery. This was evident for both groups. The present results indicated that high HRV was associated with better performance on tasks involving executive function.
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Sensory processing is affected by both endogenous and exogenous mechanisms of attention, although how these mechanisms interact in the brain has remained unclear. In the present study, we recorded event-related potentials (ERPs) to investigate how multiple stages of information processing in the brain are affected when endogenous and exogenous mechanisms are concurrently engaged. We found that the earliest stage of cortical visual processing, the striate-cortex-generated C1, was immune to attentional modulation, even when endogenous and exogenous attention converged on a common location. The earliest stage of processing to be affected in this experiment was the late phase of the extrastriate-cortex-generated P1 component, which was dominated by exogenous attention. Processing at this stage was enhanced by exogenous attention, regardless of where endogenous attention had been oriented. Endogenous attention, however, dominated a later, higher-order stage of processing indexed by an enhancement of the P300 that was unaffected by exogenous attention. Critically, between these early and late stages, an interaction was found wherein endogenous and exogenous attention produced distinct, and overlapping, effects on information processing. At the same time that exogenous attention was producing an extended enhancement of the late-P1, endogenous attention was enhancing the occipital-parietal N1 component. These results provide neurophysiological support for theories suggesting that endogenous and exogenous mechanisms represent two attention systems that can affect information processing in the brain in distinct ways. Furthermore, these data provide new evidence regarding the precise stages of neural processing that are, and are not, affected when endogenous and exogenous attentions interact.
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Do voluntary (endogenous) and involuntary (exogenous) attention have the same perceptual consequences? Here we used fMRI to examine activity in the fusiform face area (FFA--a region in ventral visual cortex responsive to faces) and frontal-parietal areas (dorsal regions involved in spatial attention) under voluntary and involuntary spatial cueing conditions. The trial and stimulus parameters were identical for both cueing conditions. However, the cue predicted the location of an upcoming target face in the voluntary condition but was nonpredictive in the involuntary condition. The predictable cue condition led to increased activity in the FFA compared to the nonpredictable cue condition. These results show that voluntary attention leads to more activity in areas of the brain associated with face processing than involuntary attention, and they are consistent with differential behavioral effects of attention on recognition-related processes.