In the last decade, cardiac vagal tone has emerged as a psychophysiological marker of many aspects of behavioral functioning in both children and adults. Research efforts during this time have produced an extensive list of vagal tone correlates that includes temperamental variables as well as both anxious/internalizing and disruptive/externalizing behaviors. This potentially confusing state of affairs is compounded by developmental shifts in vagal tone behavior relations that to date have not been elucidated. In this paper, the vagal tone literature is reviewed, and discrepancies, including the lack of specificity of vagal tone as a psychophysiological marker, are clarified. Such clarification requires that we (a) view vagal tone-behavior relations in developmental context, (b) juxtapose vagal tone-behavior relations in typical and atypical samples, and (c) consider the parasympathetic underpinnings of vagal tone as but one component in a broader model of autonomic nervous system functioning. Such a model is provided by combining Gray's motivational theory with Porges's polyvagal theory. Together these models account for behavioral and emotional differences in a diverse range of psychological disorders that are not differentiated by either model alone. Moreover, use of the integrated model offers a theory-driven approach to the study of autonomic nervous system-behavior relations.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954579401002012

Vagal tone, development, and Gray's motivational theory: toward an integrated model of autonomic nervous system functioning in psychopathology.

NMDA receptors play key roles in synaptic plasticity and neuronal development, and may be involved in learning, memory, and compensation following injury A polyclonal antibody that recognizes four of seven splice variants of NMDAR1 was made using a C-terminus peptide (30 amino acid residues) NMDAR1 is the major NMDA receptor subunit, found in most or all NMDA receptor complexes On immunoblots, this antibody labeled a single major band migrating at M(r) = 120,000 The antibody did not cross-react with extracts from transfected cells expressing other glutamate receptor subunits, nor did it label non-neuronal tissues Immunostained vibratome sections of rat tissue showed labeling in many neurons in most structures in the brain, as well as in the cervical spinal cord, dorsal root and vestibular ganglia, and in pineal and pituitary glands Staining was moderate to dense in the olfactory bulb, neocortex, striatum, some thalamic and hypothalamic nuclei, the colliculi, and many reticular, sensory, and motor neurons of the brainstem and spinal cord The densest stained cells included the pyramidal and hilar neurons of the CA3 region of the hippocampus, Purkinje cells of the cerebellum, supraoptic and magnocellular paraventricular neurons of the hypothalamus, inferior olive, red nucleus, lateral reticular nucleus, peripheral dorsal cochlear nucleus, and motor nuclei of the lower brainstem and spinal cord Ultrastructural localization of immunostaining was examined in the hippocampus, cerebral cortex, and cerebellar cortex The major staining was in postsynaptic densities apposed by unstained presynaptic terminals with round or mainly round vesicles, and in associated dendrites The pattern of staining matched that of previous in situ hybridization but differed somewhat from that of binding studies, implying that multiple types of NMDA receptors exist Comparison with previous studies of localization of other glutamate receptor types revealed that NMDAR1 may colocalize with these other types in many neurons throughout the nervous system

https://www.jneurosci.org/content/jneuro/14/2/667.full.pdf

Light and electron microscope distribution of the NMDA receptor subunit NMDAR1 in the rat nervous system using a selective anti-peptide antibody

Kalman filters are commonly used to estimate the states of a dynamic system. However, in the application of Kalman filters there is often known model or signal information that is either ignored or dealt with heuristically. For instance, constraints on state values (which may be based on physical considerations) are often neglected because they do not fit easily into the structure of the Kalman filter. A rigorous analytic method of incorporating state equality constraints in the Kalman filter is developed. The constraints may be time varying. At each time step the unconstrained Kalman filter solution is projected onto the state constraint surface. This significantly improves the prediction accuracy of the filter. The use of this algorithm is demonstrated on a simple nonlinear vehicle tracking problem.

/pdf/kalman-filtering-with-state-equality-constraints-45ynbm3xls.pdf

Kalman filtering with state equality constraints

Apnea of prematurity (AOP) is frequently managed with nasal continuous positive airway pressure (NCPAP). Nasal cannula (NC) are used at low flows (<0.5 L/min) to deliver supplemental oxygen to neonates. A number of centers use high-flow nasal cannula (HFNC) in the management of AOP without measuring the positive distending pressure (PDP) generated. Objective. To determine the NC flow required to generate PDP equal to that provided by NCPAP at 6 cm H(2)O and to assess the effectiveness of HFNC as compared NCPAP in the management of AOP. Method. Forty premature infants, gestation 28.7 +/- 0.4 weeks (mean +/- standard error of mean), postconceptual age at study 30.3 +/- 0.6 weeks, birth weight 1256 +/- 66 g, study weight 1260 +/- 63 g who were being managed with conventional NCPAP for at least 24 hours for clinically significant apnea of prematurity, were enrolled in a trial of ventilator-generated conventional NCPAP versus infant NC at flows of up to 2.5 L/min. End expiratory esophageal pressure was measured on NCPAP and on NC, and the gas flow on NC was adjusted to generate an end expiratory esophageal pressure equal to that measured on NCPAP. Two 6-hour periods were continuously recorded and the data were stored on computer. Results. The flow required to generate a comparable PDP with NC varied with the infant's weight and was represented by the equation: flow (L/min) = 0.92 + 0.68x, x = weight in kg, R = 0.72. There was no difference in the frequency and duration of apnea, bradycardia or desaturation per recording between the 2 systems. Conclusion. NC at flows of 1 to 2.5 L/min can deliver PDP in premature neonates. HFNC is as effective as NCPAP in the management of AOP.

High-Flow Nasal Cannulae in the Management of Apnea of Prematurity: A Comparison With Conventional Nasal Continuous Positive Airway Pressure

Objective:To review the use of airway pressure release ventilation (APRV) in the treatment of acute lung injury/acute respiratory distress syndrome.Data Source:Published animal studies, human studies, and review articles of APRV.Data Summary:APRV has been successfully used in neonatal, pediatric, an

Other approaches to open-lung ventilation: airway pressure release ventilation.

Apnea of prematurity: Comparative therapeutic effects of cutaneous stimulation and nasal continuous positive airway pressure

The effect of a low continuous positive airway pressure on the reflex control of respiration in the preterm infant.

An adaptive algorithm (CAMAC, control advance moving average controller) to control multiinput/multioutput physiological systems has been implemented and tested. The algorithm is a self-tuning controller that determines the input on the basis of the expected difference between the output and desired output at a time interval equal to or greater than the system dead time. The algorithm was used to simultaneously control mean arterial pressure and cardiac output in anesthetized dogs by the simultaneous computer-controlled infusion of sodium nitroprusside and dobutamine. The results demonstrate the feasibility of using CAMAC for multivariable drug delivery, but they indicate the need for further work before clinical applications are attempted.

Adaptive Multivarable Drug Delivery: Control of Artenal Pressure and Cardiac Output in Anesthetized Dogs

Maturation of cardiac control in full-term and preterm infants during sleep

A self-tuning controller was implemented for the automated infusion of sodium nitroprusside to lower mean arterial pressure in anesthetized dogs. The system incorporated a recursive least-squares parameter identifier and a modified minimum-variance controller. The onset delay was estimated on-line, the performance criterion included the cost of control, and requested step-changes were automatically translated into five successive smaller steps to reduce overshoot. The performance of the system in lowering mean arterial pressure was quantitatively compared with that of a well-trained anesthesiologist. In 10 runs in four animals, the automated system performed as well as the physician who devoted 100% of his attention to the task. Since the stability of the self-tuning controller cannot be guaranteed, such a system should be operated only in the presence of appropriate supervisory algorithms.

Peter G. Katona

Papers

Apnea of prematurity: Comparative therapeutic effects of cutaneous stimulation and nasal continuous positive airway pressure

The effect of a low continuous positive airway pressure on the reflex control of respiration in the preterm infant.

Adaptive Multivarable Drug Delivery: Control of Artenal Pressure and Cardiac Output in Anesthetized Dogs

Maturation of cardiac control in full-term and preterm infants during sleep

The self-tuning controller: comparison with human performance in the control of arterial pressure.