Cardiovascular and respiratory control mechanisms during exercise: an integrated view

1991 ◽  
Vol 160 (1) ◽  
pp. 309-340
Author(s):  
D. L. Turner
Keyword(s):  
Nervous System ◽  
Neural Coding ◽  
Phase 1 ◽  
Sensory Information ◽  
Respiratory Control ◽  
Motor Command ◽  
The Body ◽  
Control Mechanisms ◽  
Parasympathetic Nerves ◽  
Sites Of Action

Exercise can impose an immense stress upon many physiological systems throughout the body. In order that exercise performance may be optimally maintained, it is essential that a profound and complex series of responses is coordinated and controlled. The primary site for coordination is the central nervous system, whereas control mechanisms (both feedback loops and feedforward activation) involve complex sensory information, often in the form of neural coding but also in the form of blood-borne chemical signals, a number of levels of peripheral and central integration and, finally, the efferent branches of the nervous system coursing via sympathetic and parasympathetic nerves to target sites of action. The neurohumoral control of the cardiorespiratory responses to exercise has received intense attention for over two decades and some particularly important steps forward in its understanding have occurred within the last 10 years. The initial fast increase (phase 1) in cardiovascular and ventilatory flow parameters are brought about by neurally mediated muscle mechanoreceptor feedback reflexes and a feedforward ‘central motor command’. The blood pressure operating point is also raised by a combination of these two neural mechanisms. Fine control of the matching of cardiac output to ventilation may occur by means of a feedforward ventilatory control of cardiac origin. During the slower phase of adjustment (phase 2), the neurally mediated mechanisms are augmented by a cohort of humorally mediated feedback reflexes involving muscle and vascular chemoreceptors as well as being supported by central neural reverberation.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Imagination der Bewegung durch Vibrationsreize – ein neuer Ansatz in der Frühmobilisation auf der Intensivstation?

2020 ◽  
Vol 26 (4) ◽  
pp. 214-218
Author(s):  
M. Lippert-Grüner ◽  
B. Bakaláø ◽  
R. Zajíèek ◽  
F. Duška
Keyword(s):  
Nervous System ◽  
Intensive Care ◽  
Pilot Study ◽  
Sensory Information ◽  
Early Mobilization ◽  
Motor Units ◽  
The Body ◽  
Entire Body ◽  
Vibration Effect ◽  
Illusory Movement

Zusammenfassung Die Optimierung der motorischen Leistung und die Einbindung und Vernetzung bisher nicht verwendeter motorischer Einheiten sowie die vermehrte Ausschüttung neurotropher Faktoren sind zentrale Mechanismen der Vibrationswirkung, die therapeutisch auf einzelne Körperteile oder den gesamten Körper angewendet werden können. Eine Möglichkeit, die Frühmobilisation bei kritisch kranken Patienten effektiver zu gestalten und immobilitätsbedingten Veränderungen vorzubeugen, könnte die Verwendung des Vibramoov™-Systems sein. Gezielt programmierte Vibrationssequenzen stimulieren hier das Nervensystem mit sensorischen Informationen, die die Empfindung einer Bewegung nachahmen (z. B. des Gehens) und somit Regenerations- und Reor-ganisationsprozesse im zentralen Nervensystem unterstützen können. Von Bedeutung ist dieser Therapieansatz vor allem bei Patienten, bei denen aufgrund ihres Zustandes konventionelle Maßnahmen nicht oder nur eingeschränkt durchgeführt werden können. Da bisher keine Erfah-rungen zur Anwendung bei intensivpflichtigen Patienten verfügbar sind, wurde eine Pilotstudie durchgeführt mit der Fragestellung, ob diese Therapieform sicher ist und im normalen Betrieb auf der Intensivstation verwendet werden kann. Die Ergebnisse der Pilotstudie mit fünf Patienten zei-gen, dass die Anwendung von Vibramoov™ zu keiner wesentlichen Veränderung kardiopulmo-naler Parameter im Sinne einer Non-Toleranz führte und im klinischen Setting gut umsetzbar war. Schlüsselwörter: Frührehabilitation, Imagination von Bewegung, Intensivstation, Vibramoov™ Imagination of movement through vibrational stimuli – a new approach to early mobilization in intensive care units? A pilot study Abstract The optimization of motor performance and the integration and networking of previously unused motor units, as well as the increased release of neurotrophic factors, are central mechanisms related to the vibration effect that can be applied therapeutically to individual parts of the body or to the entire body. One way to make early mobilization more effective in critically ill patients and to prevent changes due to immobility could be rehabilitation with functional proprioceptive stimulation, also known as “illusory movement”. Specifically programmed vibration sequences stimulate the nervous system with sensory information that mimics the sensation of movement (e. g., walking) and can thus support regeneration and reorganization processes in the central nervous system. This therapeutic approach is particularly important for patients who, due to their condition, cannot – or only to a limited extent – carry out conventional measures. Since no experience has so far been available for use in intensive care patients, we carried out a pilot study to answer the question of whether this form of therapy can be used safely and in normal operations in the intensive care unit. The results of the pilot study with 5 patients showed that the use of Vibramoov™ did not lead to any significant change in cardiopulmonary parameters in terms of non-tolerance and was easy to implement in a clinical setting. Keywords: early rehabilitation, illusory movements, ICU, functional proprio-ceptive stimulation

Mechanisms for generating temporal filters in the electrosensory system

1999 ◽  
Vol 202 (10) ◽  
pp. 1281-1289 ◽  
Author(s):  
G.J. Rose ◽  
E.S. Fortune
Keyword(s):  
Nervous System ◽  
Discharge Rate ◽  
Temporal Structure ◽  
Sensory Information ◽  
Gain Control ◽  
Membrane Properties ◽  
Control Mechanisms ◽  
Temporal Features ◽  
Level Of Activity ◽  
The Central Nervous System

Temporal patterns of sensory information are important cues in behaviors ranging from spatial analyses to communication. Neural representations of the temporal structure of sensory signals include fluctuations in the discharge rate of neurons over time (peripheral nervous system) and the differential level of activity in neurons tuned to particular temporal features (temporal filters in the central nervous system). This paper presents our current understanding of the mechanisms responsible for the transformations between these representations in electric fish of the genus Eigenmannia. The roles of passive and active membrane properties of neurons, and frequency-dependent gain-control mechanisms are discussed.

scholarly journals Distinct Proximal and Distal Corticospinal Signals Embed Limb Dynamics Through the Modulation of Stiffness

2019 ◽  
Author(s):  
R. L. Hardesty ◽  
P. H. Ellaway ◽  
V. Gritsenko
Keyword(s):  
Nervous System ◽  
Physical Properties ◽  
Neural Control ◽  
Primary Motor Cortex ◽  
Equations Of Motion ◽  
Task Demands ◽  
The Body ◽  
Control Mechanisms ◽  
Neural Signals ◽  
Limb Dynamics

AbstractThe complexities of the human musculoskeletal system and its interactions with the environment creates a difficult challenge for the neural control of movement. The consensus is that the nervous system solves this challenge by embedding the dynamical properties of the body and the environment. However, the modality of control signals and how they are generated appropriately for the task demands are a matter of active debate. We used transcranial magnetic stimulation over the primary motor cortex to show that the excitability of the corticospinal tract is modulated to compensate for limb dynamics during reaching tasks in humans. Surprisingly, few profiles of corticospinal modulation in some muscles and conditions reflected Newtonian parameters of movement, such as kinematics or active torques. Instead, the overall corticospinal excitability was differentially modulated in proximal and distal muscles, which corresponded to different stiffness at proximal and distal joints. This suggests that the descending corticospinal signal determines the proximal and distal impedance of the arm for independent functional control of reaching and grasping.Significance StatementThe nervous system integrates both the physical properties of the human body and the environment to create a rich repertoire of actions. How these calculations are happening remains poorly understood. Neural activity is known to be correlated with different variables from the Newtonian equations of motion that describe forces acting on the body. In contrast, our data show that the overall activity of the descending neural signals is less related to the individual Newtonian variables and more related to limb impedance. We show that the physical properties of the arm are controlled by two distinct proximal and distal descending neural signals modulating components of limb stiffness. This identifies distinct neural control mechanisms for the transport and manipulation actions of reach.

Major sensory and motor systems

2013 ◽  
Author(s):  
Martin E. Atkinson
Keyword(s):  
Nervous System ◽  
Cerebral Cortex ◽  
No Value ◽  
Cranial Nerves ◽  
Sensory Information ◽  
The Body ◽  
Functional Responses ◽  
Motor Pathways ◽  
Sensory Pathways ◽  
And Function

The previous chapter provided an overview of the anatomy of the CNS, concentrating on structures that can be seen during dissection of the human brain and spinal cord or the study of anatomical models of these structures. Some indication of the function of different components of the CNS has been given in Chapter 15, but this chapter shows how the various anatomical components of the CNS are functionally linked together through sensory and motor pathways. These pathways enable the nervous system to convey information over considerable distances, to integrate the information, and formulate functional responses that coordinate activities of different parts of the body. It will be necessary to introduce some other structures in addition to those described in Chapter 15 during the description of major pathways; most are not visible to the naked eye and even when seen in microscopical sections, they require considerable practice to distinguish them. However, they are important landmarks or relay stations in the central nervous pathways and you need to know of them for a full understanding of pathways. As emphasized in Chapter 14, our views of the structure and function of many aspects of the nervous system are constantly subject to revision in the light of new clinical and experimental observations and methods of investigation. This applies to nerve pathways just as much as any other aspect of the nervous system. This chapter presents a summary of current views on somatic sensory and motor functions and their application to the practice of dentistry. The special sensory pathways of olfaction, vision, and hearing are described in Chapter 18 in the context of the cranial nerves that form the first part of these pathways. The information conveyed from the periphery by the sensory components of spinal and cranial nerves is destined to reach the cerebral cortex or the cerebellum. You will be conscious of sensory information that reaches the cerebral cortex, but mostly unaware of information that does not travel to the cortex. However, this does not mean that sensory information that does not attain cortical levels is of no value. For example, sensory neurons or their collateral processes form the afferent limbs of many reflex arcs.

Sympathoadrenal system in neuroendocrine control of glucose; mechanisms involved in the liver, pancreas, and adrenal gland under hemorrhagic and hypoglycemic stress

1992 ◽  
Vol 70 (2) ◽  
pp. 167-206 ◽  
Author(s):  
Nobuharu Yamaguchi
Keyword(s):  
Nervous System ◽  
Autonomic Nervous System ◽  
Adrenal Gland ◽  
Nerve Stimulation ◽  
Sympathetic Nerves ◽  
Control Mechanisms ◽  
Sympathoadrenal System ◽  
Neuroendocrine Control ◽  
Functional Implication ◽  
Parasympathetic Nerves

Glucose homeostasis is maintained by complex neuroendocrine control mechanisms, involving three peripheral organs: the liver, pancreas, and adrenal gland, all of which are under control of the autonomic nervous system. During the past decade, abundant results from various studies on neuroendocrine control of glucose have been accumulated. The principal objective of this review is to provide overviews of basic adrenergic mechanisms closely related to glucose control in the three peripheral organs, and then to discuss the integrated glucoregulatory mechanisms in hemorrhage-induced hypotension and insulin-induced hypoglycemia with special reference to sympathoadrenal control mechanisms. The liver is richly innervated by sympathetic and parasympathetic nerves. The functional implication in glucoregulation of sympathetic nerves has been well-documented, while that of parasympathetic nerves remains less understood. More recently, hepatic glucoreceptors have been postulated to be coupled with capsaicin-sensitive afferent nerves, conveying sensory signals of blood glucose concentration to the central nervous system. The pancreas is also richly supplied by the autonomic nervous system. Besides the well documented adrenergic and cholinergic mechanisms, the potential implication of peptidergic neurotransmission by neuropeptide Y and neuromodulation by galanin has recently been postulated in the endocrine secretory function. Presynaptic interactions of these putative peptidergic neurotransmitters with the classic transmitters, noradrenaline and acetylcholine, in the pancreas remain to be clarified. It may be of particular interest that it was vagus nerve stimulation that caused a dominant release of neuropeptide Y over that caused by sympathetic nerve stimulation in the pig pancreas. The adrenal medulla receives its main nerve supply from the greater and lesser splanchnic nerves. Adrenal medullary catecholamine secretion appears to be regulated by three distinct local mechanisms: adrenoceptor-mediated, dihydropyridine-sensitive Ca2+ channel-mediated, and capsaicin-sensitive sensory nerve-mediated mechanisms. In response to hemorrhagic hypotension and insulin-induced hypoglycemia, the sympathoadrenal system is activated resulting in increases of adrenal catecholamine and pancreatic glucagon secretions, both of which are significantly implicated in glucoregulatory mechanisms. An increase in sympathetic nerve activity occurs in the liver during hemorrhagic hypotension and is also likely to occur in the pancreas in response to insulin-induced hypoglycemia. The functional implication of hepatic and central glucoreceptors has been suggested in the increased secretion of glucose counterregulatory hormones, particularly catecholamines and glucagon.Key words: sympathetic nerves, adrenal medulla, catecholamines, glucose, hypoglycemia, hemorrhage.

Grasp stability during manipulative actions

1994 ◽  
Vol 72 (5) ◽  
pp. 511-524 ◽  
Author(s):  
Roland S. Johansson ◽  
Kelly J. Cole
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Precision Grip ◽  
Sensory Information ◽  
Parameter Control ◽  
Control Mechanisms ◽  
Control Processes ◽  
Grasp Stability ◽  
The Central Nervous System ◽  
Fingertip Forces

The control of adequate contact forces between the skin and an object (grasp stability) is examined for two classes of prehensile actions that employ a precision grip: lifting objects that are "passive" (subject only to inertial forces and gravity) and preventing "active" objects from moving. For manipulating either passive or active objects the relevant fingertip forces are determined by at least two control processes. "Anticipatory parameter control" is a feedforward controller that specifies the values for motor command parameters on the basis of predictions of critical characteristics, such as object weight and skin–object friction, and initial condition information. Through vision, for instance, common objects can be identified in terms of the fingertip forces necessary for a successful lift according to previous experiences. After contact with the object, sensory information representing discrete mechanical events at the fingertips can (i) automatically modify the motor commands, (ii) update sensorimotor memories supporting the anticipatory parameter control policy, (iii) inform the central nervous system about completion of the goal for each action phase, and (iv) trigger commands for the task's sequential phases. Hence, the central nervous system monitors specific, more or less expected peripheral sensory events to produce control signals that are appropriate for the task at its current phase. The control is based on neural modelling of the entire dynamics of the control process that predicts the appropriate output for several steps ahead. This "discrete-event, sensor-driven control" is distinguished from feedback or other continuous regulation. Using these two control processes, slips are avoided at each digit by independent control mechanisms that specify commands and process sensory information on a local, digit-specific basis. This scheme obviates explicit coordination of the digits and is employed when independent nervous systems lift objects. The force coordination across digits is an emergent property of the local control mechanisms operating over the same time span.Key words: precision grip, hand, grasp stability, grasp force, tactile afferents.

Anticipation requires adaptation

2008 ◽  
Vol 31 (2) ◽  
pp. 199-200
Author(s):  
Christian Balkenius ◽  
Peter Gärdenfors
Keyword(s):  
Nervous System ◽  
Time Scales ◽  
Sensory Information ◽  
The Body ◽  
Predictive Mechanisms ◽  
Different Time Scales

AbstractTo successfully interact with a dynamic world, our actions must be guided by a continuously changing anticipated future. Such anticipations must be tuned to the processing delays in the nervous system as well as to the slowness of the body, something that requires constant adaptation of the predictive mechanisms, which in turn require that sensory information be processed at different time-scales.

Nerve and muscle

2012 ◽  
Keyword(s):  
Skeletal Muscle ◽  
Nervous System ◽  
Smooth Muscle ◽  
Cardiac Muscle ◽  
Clinical Symptoms ◽  
Sensory Information ◽  
The Body ◽  
Membrane Receptors ◽  
Excitable Cells ◽  
Chemical Synapses

Higher animals have four basic tissue types: epithelial tissue, connective tissue, nervous tissue, and muscle. Of these, nerve and muscle are grouped together as ‘excitable cells’ because the cell membrane has the ability to vary membrane ion conductance and membrane voltage so as to transmit meaningful signals within and between cells. Within excitable cells information is transmitted using either an amplitude-modulated (AM) code using slow, electrotonic potentials, or a frequency-modulated (FM) code when signalling is by action potentials. Much of the signalling between excitable cells occurs at chemical synapses where a chemical neurotransmitter is released from presynaptic cells and then interacts with postsynaptic membrane receptors. Clinical symptoms can arise when the release of chemical neurotransmitters is disturbed, or when availability of postsynaptic receptors is altered. Thus, a reduction in dopamine release from basal ganglia substantia nigra cells is found in Parkinson’s disease, while myasthenia gravis results from loss of nicotinic acetylcholine receptors at the neuromuscular junction of skeletal muscle. Sometimes transmission from cell to cell is not by chemical neurotransmitter but by electrical synapses, where gap-junctions provide direct electrical connectivity. Transmission between cardiac muscle cells occurs in this way. Some cardiac arrhythmias, such as Wolff –Parkinson–White syndrome, are a consequence of an abnormal path of electrical conduction between cardiac muscle fibres. Sensory cells on and within the body pass information via afferent pathways from the peripheral nervous system into the central nervous system (CNS). CNS processes and sensory information are integrated to produce outputs from the CNS. These outputs pass by various efferent routes to the effector organs: skeletal muscle, cardiac muscle, smooth muscle, and glands. It is through these effectors that the CNS is able to exert control over the body and to interact with the environment. Alterations of function anywhere in the afferent, integrative, or efferent aspects of the system, as well as defects in the effectors themselves, are likely to lead to significant clinical symptoms and signs. The efferent outflow from the CNS has two major components. One, the somatic nervous system, innervates only skeletal muscle. The other is the autonomic nervous system (ANS), which innervates cardiac muscle, smooth muscle, and the glands of the viscera and skin.

scholarly journals Comparison of the 3-D patterns of the parasympathetic nervous system in the lung at late developmental stages between mouse and chicken

2018 ◽  
Author(s):  
Tadayoshi Watanabe ◽  
Ryo Nakamura ◽  
Yuta Takase ◽  
Etsuo A Susaki ◽  
Hiroki R Ueda ◽  
...  
Keyword(s):  
Nervous System ◽  
Gas Exchange ◽  
Parasympathetic Nervous System ◽  
Developmental Stages ◽  
Close Association ◽  
Smooth Muscles ◽  
Distribution Patterns ◽  
The Body ◽  
Anatomy And Physiology ◽  
Parasympathetic Nerves

Although the basic schema of the body plan is similar among different species of amniotes (mammals, birds, and reptiles), the lung is an exception. Here, anatomy and physiology are considerably different, particularly between mammals and birds. In mammals, inhaled and exhaled airs mix in the airways, whereas in birds the inspired air flows unidirectionally without mixing with the expired air. This bird-specific respiration system is enabled by the complex tubular structures called parabronchi where gas exchange takes place, and also by the bellow-like air sacs appended to the main part of the lung. That the lung is predominantly governed by the parasympathetic nervous system has been shown mostly by physiological studies in mammals. However, how the parasympathetic nervous system in the lung is established during late development has largely been unexplored both in mammals and birds. In this study, by combining immunocytochemistry, the tissue-clearing CUBIC method, and ink-injection to airways, we have visualized the 3-D distribution patterns of parasympathetic nerves and ganglia in the lung at late developmental stages of mice and chickens. These patterns were further compared between these species, and three prominent similarities emerged: (1) parasympathetic postganglionic fibers and ganglia are widely distributed in the lung covering the proximal and distal portions, (2) the gas exchange units, alveoli in mice and parabronchi in chickens, are devoid of parasympathetic nerves, (3) parasympathetic nerves are in close association with smooth muscle cells, particularly at the base of the gas exchange units. These observations suggest that despite gross differences in anatomy, the basic mechanisms underlying parasympathetic control of smooth muscles and gas exchange might be conserved between mammals and birds.

scholarly journals Tactile suppression stems from sensation-specific sensorimotor predictions

2021 ◽  
Author(s):  
Elena Fuehrer ◽  
Dimitris Voudouris ◽  
Alexandra Lezkan ◽  
Knut Drewing ◽  
Katja Fiehler
Keyword(s):  
Sensory Feedback ◽  
Sensory Information ◽  
Motor Command ◽  
The Body ◽  
Textured Surfaces ◽  
Vibrotactile Feedback ◽  
The World ◽  
Tactile Sensations ◽  
Predictive Mechanisms

The ability to sample sensory information with our hands is crucial for smooth and efficient interactions with the world. Despite this important role of touch, tactile sensations on a moving hand are perceived weaker than when presented on the same but stationary hand.1-3 This phenomenon of tactile suppression has been explained by predictive mechanisms, such as forward models, that estimate future sensory states of the body on the basis of the motor command and suppress the associated predicted sensory feedback.4 The origins of tactile suppression have sparked a lot of debate, with contemporary accounts claiming that suppression is independent of predictive mechanisms and is instead akin to unspecific gating.5 Here, we target this debate and provide evidence for sensation-specific tactile suppression due to sensorimotor predictions. Participants stroked with their finger over textured surfaces that caused predictable vibrotactile feedback signals on that finger. Shortly before touching the texture, we applied external vibrotactile probes on the moving finger that either matched or mismatched the frequency generated by the stroking movement. We found stronger suppression of the probes that matched the predicted sensory feedback. These results show that tactile suppression is not limited to unspecific gating but is specifically tuned to the predicted sensory states of a movement.

Sign in / Sign up

Export Citation Format

Share Document