During the past decade, catheter ablation of atrial fibrillation (AF) has evolved rapidly from an investigational procedure to its current status as a commonly performed ablation procedure in many major hospitals throughout the world. Surgical ablation of AF, using either standard or minimally invasive techniques, is also performed in many major hospitals throughout the world.

In 2007, an initial Consensus Statement on Catheter and Surgical AF Ablation was developed as a joint effort of the Heart Rhythm Society, the European Heart Rhythm Association, and the European Cardiac Arrhythmia Society.1 The 2007 document was also developed in collaboration with the Society of Thoracic Surgeons and the American College of Cardiology. Since the publication of the 2007 document, there has been much learned about AF ablation, and the indications for these procedures have changed. Therefore the purpose of this 2012 Consensus Statement is to provide a state-of-the-art review of the field of catheter and surgical ablation of AF and to report the findings of a Task Force, convened by the Heart Rhythm Society, the European Heart Rhythm Association, and the European Cardiac Arrhythmia Society and charged with defining the indications, techniques, and outcomes of this procedure. Included within this document are recommendations pertinent to the design of clinical trials in the field of AF ablation, including definitions relevant to this topic.

This statement summarizes the opinion of the Task Force members based on an extensive literature review as well as their own experience. It is directed to all health care professionals who are involved in the care of patients with AF, particularly those who are undergoing, or are being considered for, catheter or surgical ablation procedures for AF. This statement is not intended to recommend or promote catheter ablation of AF. Rather the ultimate judgment regarding care of a particular patient …

2012 HRS/EHRA/ECAS expert consensus statement on catheter and surgical ablation of atrial fibrillation: Recommendations for patient selection, procedural techniques, patient management and follow-up, definitions, endpoints, and research trial design

Converging evidence now indicates that the amygdala plays a crucial role in the development and expression of conditioned fear. Conditioned fear is a hypothetical construct used to explain the cluster of behavioral effects produced when an initially neutral stimulus is consistently paired with an aversive stimulus. For example, when a light, which initially has no behavioral effect, is paired with an aversive stimulus such as a footshock, the light alone can elicit a constellation of behaviors that are typically used to define a state of fear in animals. To explain these findings, it is generally assumed (cf. McAllister & McAllister 1971 ) that during light-shock pair­ ings (training session ), the shock elicits a variety of behaviors that can be used to infer a central state of fear (unconditioned responses-Figure 1 ). After pairing , the light can produce the same central fear state and thus the same set of bchaviors formerly produced by thc shock. Moreover, the behavioral effects that are produced in animals by this formerly neutral stimulus (now called a conditioned stimulus-CS ) are similar in many respects to the constellation of behaviors that are used to diagnose gener­ alized anxiety in humans (Table 1 ). This chapter summarizes data sup­ porting the idea that the amygdala, and its many efferent projections, may represent a central fear system involved in both the expression and acquisition of conditioned fear.

The role of the amygdala in fear and anxiety

The synucleinopathy, idiopathic Parkinson's disease, is a multisystem disorder that involves only a few predisposed nerve cell types in specific regions of the human nervous system. The intracerebral formation of abnormal proteinaceous Lewy bodies and Lewy neurites begins at defined induction sites and advances in a topographically predictable sequence. As the disease progresses, components of the autonomic, limbic, and somatomotor systems become particularly badly damaged. During presymptomatic stages 1-2, inclusion body pathology is confined to the medulla oblongata/pontine tegmentum and olfactory bulb/anterior olfactory nucleus. In stages 3-4, the substantia nigra and other nuclear grays of the midbrain and forebrain become the focus of initially slight and, then, severe pathological changes. At this point, most individuals probably cross the threshold to the symptomatic phase of the illness. In the end-stages 5-6, the process enters the mature neocortex, and the disease manifests itself in all of its clinical dimensions.

Stages in the development of Parkinson’s disease-related pathology

The location of neurons generating the rhythm of breathing in mammals is unknown. By microsection of the neonatal rat brainstem in vitro, a limited region of the ventral medulla (the pre-Botzinger Complex) that contains neurons essential for rhythmogenesis was identified. Rhythm generation was eliminated by removal of only this region. Medullary slices containing the pre-Botzinger Complex generated respiratory-related oscillations similar to those generated by the whole brainstem in vitro, and neurons with voltage-dependent pacemaker-like properties were identified in this region. Thus, the respiratory rhythm in the mammalian neonatal nervous system may result from a population of conditional bursting pacemaker neurons in the pre-Botzinger Complex.

https://science.sciencemag.org/content/sci/254/5032/726.full.pdf

Pre-Botzinger Complex: A Brainstem Region That May Generate Respiratory Rhythm in Mammals

http://www.unicog.org/publications/DehaeneChangeux_ReviewConsciousness_Neuron2011.pdf

Experimental and Theoretical Approaches to Conscious Processing

Butyrylcholinesterase is a serine hydrolase related to acetylcholinesterase that catalyses the hydrolysis of esters of choline, including acetylcholine. Butyrylcholinesterase has unique enzymatic properties and is widely distributed in the nervous system, pointing to its possible involvement in neural function. Here, we summarize the biochemical properties of butyrylcholinesterase and review the evidence that this enzyme has important roles in cholinergic neurotransmission and could be involved in other nervous system functions and in neurodegenerative diseases.

Neurobiology of butyrylcholinesterase.

The aim of this study was to map the viscerotopic representation of the upper alimentary tract in the sensory ganglia of the IXth and Xth cranial nerves and in the subnuclei of the solitary and spinal trigeminal tracts. Therefore, in 172 rats 0.5-65 microliters of horseradish peroxidase (HRP), wheat germ agglutinin-HRP, or cholera toxin-HRP were injected into the trunks and major branches of the IXth and Xth cranial nerves as well as into the musculature and mucosa of different levels of the upper alimentary and respiratory tracts. The results demonstrate that the sensory ganglia of the IXth and Xth nerves form a fused ganglionic mass with continuous bridges of cells connecting the proximal and distal portions of the ganglionic complex. Ganglionic perikarya were labeled in crude, overlapping topographical patterns after injections of tracers into nerves and different parts of the upper alimentary tract. After injections into the soft palate, pharynx, esophagus, and stomach, anterograde labeling was differentially distributed in distinct subnuclei in the nucleus of the tractus solitarius (NTS). Palatal and pharyngeal injections resulted primarily in labeling of the interstitial and intermediate subnuclei of the NTS and in the paratrigeminal islands (PTI) and spinal trigeminal complex. Esophageal and stomach wall injections resulted in labeling primarily of the subnucleus centralis and subnucleus gelatinosus, respectively. The distribution of upper alimentary tract vagal-glossopharyngeal afferents in the medulla oblongata has two primary groups of components, i.e., a viscerotopic distribution in the NTS involved in ingestive and respiratory reflexes and a distribution coextensive with fluoride-resistant acid-phosphatase-positive regions of the PTI and spinal trigeminal nucleus presumably involved in visceral reflexes mediated by nociceptive or chemosensitive C fibers.

Viscerotopic representation of the upper alimentary tract in the rat: sensory ganglia and nuclei of the solitary and spinal trigeminal tracts.

Background

The extent and locations of intrinsic cardiac ganglia on the human heart were investigated to facilitate studying their function.



Methods

The locations and number of major intrinsic cardiac ganglia were determined in six human hearts by means of microdissection following methylene blue staining. Light and electron microscopic analyses were performed on right atrial and cranial medial ventricular ganglia obtained from 12 other human hearts.



Results

Gross anatomy: Collections of ganglia associated with nerves, i.e., ganglionated plexuses, were observed consistently in five atrial and five ventricular regions. Occasional ganglia were located in other atrial and ventricular regions. Atrial ganglionated plexuses were identified on 1) the superior surface of the right atrium, 2) the superior surface of the left atrium, 3) the posterior surface of the right atrium, 4) the posterior medial surface of the left atrium (the latter two fuse medially where they extend anteriorly into the interatrial septum), and 5) the inferior and lateral aspect of the posterior left atrium. Ventricular ganglionated plexuses were located in fat 1) surrounding the aortic root, 2) at the origins of the right and left coronary arteries (the latter extending to the origins of the left anterior descending and circumflex coronary arteries), 3) at the origin of the posterior descending coronary artery, 4) adjacent to the origin of the right acute marginal coronary artery, and 5) at the origin of the left obtuse marginal coronary artery. Microscopic anatomy: Ganglia ranged in size from those containing a few neurons to large ganglia measuring up to 0.5 × 1 mm. The human heart is estimated to contain more than 14,000 neurons. Neuronal somata varied in size and shape. Many axon terminals in intrinsic cardiac ganglia contained large numbers of small, clear, round vesicles that formed asymmetrical axodendritic synapses, whereas a few axons contained large, dense-cored vesicles.



Conclusions

The human intrinsic cardiac nervous system is distributed more extensively than was considered previously, most of its ganglia being located on the posterior surfaces of the atria and superior aspect of the ventricles. Each ganglion therein contains a variety of neurons that are associated with complex synaptology. Anat. Rec. 247:289-298, 1997. © 1997 Wiley-Liss, Inc.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/%28SICI%291097-0185%28199702%29247%3A2%3C289%3A%3AAID-AR15%3E3.0.CO%3B2-L

Gross and microscopic anatomy of the human intrinsic cardiac nervous system

The nucleus ambiguus has been reported to innervate various thoracic and abdominal viscera in addition to the musculature of the upper alimentary tract. However, the literature is contradictory as to how different regions of the nucleus ambiguus innervate specific organs. Therefore, a systematic investigation of the viscerotopic organization of the nucleus ambiguus was undertaken. In 102 rats, 0.5–10.0 μl of HRP, WGA-HRP, cholera toxin-HRP or fluorescent tracers were injected into the IXth, Xth, and XIth cranial nerves and the major branches of the Xth as well as organs supplied by them.



The results demonstrate that the nucleus ambiguus in the rat is made up of two major longitudinal divisions: a dorsal division comprised of three rostrocaudally aligned subdivisions representing the special visceral efferent component, and a ventral division comprised of at least two subdivisions representing the general visceral efferent component. The dorsal division corresponds to the nucleus ambiguus in the narrow sense and comprises a rostral esophagomotor compact formation, an intermediate pharyngolaryngomotor semicompact formation, and a caudal laryngomotor loose formation. Each of these formations displays a characteristic dendroarchitecture. The stylopharyngeal and cricothyroid motoneurons are displaced rostrad from the main pharyngeal and laryngeal motoneuronal pools. Thyropharyngeal (lower constrictor) motoneurons occupy the rostral half of the semi-compact formation and hyopharyngeal (middle constrictor) motoneurons its entire length. The ventral division of the nucleus ambiguus corresponds to the external formation, extends along the entire length of the medulla oblongata, and contains preganglionic neurons innervating the heart and supradiaphragmatic structures innervated by the glossopharyngeal and the superior laryngeal nerves.

David A. Hopkins

Papers

Neurobiology of butyrylcholinesterase.

Viscerotopic representation of the upper alimentary tract in the rat: sensory ganglia and nuclei of the solitary and spinal trigeminal tracts.

Gross and microscopic anatomy of the human intrinsic cardiac nervous system

Viscerotopic representation of the upper alimentary tract in the medulla oblongata in the rat: the nucleus ambiguus.

The central distribution of the cervical vagus nerve and gastric afferent and efferent projections in the rat.