Phasic heart rate changes during word translation of different difficulties

Sensorimotor Feedback Control Dysfunction as a Marker of Posttraumatic Stress Disorder

BACKGROUND

Posttraumatic stress disorder (PTSD) is characterized not only by its direct association with traumatic events but also by a potential deficit in inhibitory control across emotional, cognitive, and sensorimotor domains. Recent research has shown that a continuous sensorimotor feedback control task, the rapid assessment of motor processing paradigm, can yield reliable measures of individual sensorimotor control performance. This study used this paradigm to investigate control deficits in PTSD compared with both a healthy volunteer group and a non-PTSD psychiatric comparison group.

METHODS

We examined control processing using the rapid assessment of motor processing paradigm in a sample of 40 individuals with PTSD, matched groups of 40 individuals with mood and anxiety complaints, and 40 healthy control participants. We estimated Kp (drive) and Kd (damping) parameters using a proportional-derivative control modeling approach.

RESULTS

The Kp parameter was lower in the PTSD group than in the healthy control (Cohen's d = 0.86) and mood and anxiety (Cohen's d = 0.63) groups. After controlling for color-word inhibition, Kp remained lower in the PTSD group than in the healthy control (Cohen's d = 0.79) and mood and anxiety (Cohen's d = 0.62) groups. Mediation analysis showed that Kd significantly mediated the relationship between PTSD and control deficits in the Kp parameter, with 96% of the effect being mediated by Kd.

CONCLUSIONS

These findings underscore the potential of using dynamic control paradigms to elucidate the control dysfunctions in PTSD and suggest that different psychiatric conditions may distinctly influence subcomponents of sensorimotor control.

The infant-doctor relationship: an examination of infants' distress reactions in the presence of a doctor

Fear of doctors is a common source of distress among infants; however, the underlying sources of this distress are unknown. To investigate the doctor-infant relationship, the behaviors of 61 healthy infants (176-617 days old) were observed in a simulated examination room. Their behaviors and electrocardiograms were recorded. Two groups of infants were analyzed: those who cried and those who did not. When an experimenter dressed in the doctor's attire entered the room, all 9 infants who were crying (14.8% of all infants) stopped crying, all infants gazed at the experimenter, and their mean heart rate (HR) decreased. After the auscultation started, 29.5% of all infants cried, and the HRs of infants who cried were higher than those of infants who did not cry. During the auscultation, 80.0% of infants who cried averted from the experimenter, while 34.4% of infants who did not cry. Within 5 s of gazing at the stethoscope, the number of infants who cried increased from 3 to 12, and their mean HR also increased. Our findings suggest that the fear of doctors is not due to the appearance of doctors but rather to specific actions performed by doctors, such as auscultation. Infants may regard a doctor's appearance as a source of interest. Furthermore, a stethoscope is a possible trigger for infants' crying. These behavioral observations suggest the potential for patient-centered care for infants.

The frequency architecture of brain and brain body oscillations: an analysis

Research on brain oscillations has brought up a picture of coupled oscillators. Some of the most important questions that will be analyzed are, how many frequencies are there, what are the coupling principles, what their functional meaning is, and whether body oscillations follow similar coupling principles. It is argued that physiologically, two basic coupling principles govern brain as well as body oscillations: (i) amplitude (envelope) modulation between any frequencies m and n, where the phase of the slower frequency m modulates the envelope of the faster frequency n, and (ii) phase coupling between m and n, where the frequency of n is a harmonic multiple of m. An analysis of the center frequency of traditional frequency bands and their coupling principles suggest a binary hierarchy of frequencies. This principle leads to the foundation of the binary hierarchy brain body oscillation theory. Its central hypotheses are that the frequencies of body oscillations can be predicted from brain oscillations and that brain and body oscillations are aligned to each other. The empirical evaluation of the predicted frequencies for body oscillations is discussed on the basis of findings for heart rate, heart rate variability, breathing frequencies, fluctuations in the BOLD signal, and other body oscillations. The conclusion is that brain and many body oscillations can be described by a single system, where the cross talk - reflecting communication - within and between brain and body oscillations is governed by m : n phase to envelope and phase to phase coupling.

Brisk heart rate and EEG changes during execution and withholding of cue-paced foot motor imagery

Cue-paced motor imagery (MI) is a frequently used mental strategy to realize a Brain-Computer Interface (BCI). Recently it has been reported that two MI tasks can be separated with a high accuracy within the first second after cue presentation onset. To investigate this phenomenon in detail we studied the dynamics of motor cortex beta oscillations in EEG and the changes in heart rate (HR) during visual cue-paced foot MI using a go (execution of imagery) vs. nogo (withholding of imagery) paradigm in 16 healthy subjects. Both execution and withholding of MI resulted in a brisk centrally localized beta event-related desynchronization (ERD) with a maximum at ~400 ms and a concomitant HR deceleration. We found that response patterns within the first second after stimulation differed between conditions. The ERD was significantly larger in go as compared to nogo. In contrast the HR deceleration was somewhat smaller and followed by an acceleration in go as compared to nogo. These findings suggest that the early beta ERD reflects visually induced preparatory activity in motor cortex networks. Both the early beta ERD and the HR deceleration are the result of automatic operating processes that are likely part of the orienting reflex (OR). Of interest, however, is that the preparatory cortical activity is strengthened and the HR modulated already within the first second after stimulation during the execution of MI. The subtraction of the HR time course of the nogo from the go condition revealed a slight HR acceleration in the first seconds most likely due to the increased mental effort associated with the imagery process.

Correlation between EEG burst-to-burst intervals and HR acceleration in preterm infants

One objective of this paper is to confirm the coupling between heart rate (HR) changes and electroencephalographic (EEG) bursts (as reported for the first time in Pfurtscheller et al. [K. Pfurtscheller, G.R. Müller-Putz, B. Urlesberger, W. Müller, G. Pfurtscheller, Relationship between slow-wave EEG bursts and heart rate changes in preterm infants, Neurosci. Lett. 385 (2) (2005) 126-130]) in a larger group of preterm infants. Other objectives are to report on semi-automatic detection of burst-to-burst intervals (BBI, time period between the onsets of 2 consecutive EEG bursts) and on correlations between BBI and HR changes. A group of 34 preterm infants with a conceptional age (CA) of 35.9+/-0.6 weeks (mean+/-S.D.) was studied. Periods with a length of about 10 min with low HR variability and discontinuous EEG were selected from long-term EEG and ECG registrations and analyzed. From the automated detection of EEG bursts, an estimate for the mean burst-to-burst interval was obtained. EEG trials with a duration of 16s and a single EEG burst in the middle, were selected and averaged together with the corresponding instantaneous HR trials. It was found that preterm infants without evidence of neurological deficit and with normal development revealed a mean BBI of 13.4+/-2.6s (mean+/-S.D.) and a HR increase of 1.7+/-0.9 bpm (mean+/-S.D.) during the occurrence of EEG bursts. This HR increase is comparable with the earlier reported increase of 1.9+/-0.8 bpm. A significant negative correlation of r=0.453 (p<0.01) was found between BBI and HR increase and a positive correlation between CA and HRV (r=0.438, p<0.01) and between CA and HRI (r=0.452, p<0.01).

Self-initiation of EEG-based brain-computer communication using the heart rate response

Self-initiation, that is the ability of a brain-computer interface (BCI) user to autonomously switch on and off the system, is a very important issue. In this work we analyze whether the respiratory heart rate response, induced by brisk inspiration, can be used as an additional communication channel. After only 20 min of feedback training, ten healthy subjects were able to self-initiate and operate a 4-class steady-state visual evoked potential-based (SSVEP) BCI by using one bipolar ECG and one bipolar EEG channel only. Threshold detection was used to measure a beat-to-beat heart rate increase. Despite this simple method, during a 30 min evaluation period on average only 2.9 non-intentional switches (heart rate changes) were detected.