Physiological Regulation: How It Really Works

Ramsay, Douglas S.; Woods, Stephen C.

doi:10.1016/j.cmet.2016.08.004

Cited by 42 publications

(36 citation statements)

References 45 publications

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“…Memorial representations of prior experience with food are then used to guide future ingestive behavior. One manifestation of the involvement of learning and memory is anticipatory responding 11 …”

Section: Monitoring Nutrientsmentioning

confidence: 99%

Blaming the Brain for Obesity: Integration of Hedonic and Homeostatic Mechanisms

2017

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The brain plays a key role in the controls of energy intake and expenditure and many genes associated with obesity are expressed in the central nervous system. Technological and conceptual advances in both basic and clinical neurosciences have expanded the traditional view of homeostatic regulation of body weight by mainly the hypothalamus to include hedonic controls of appetite by cortical and subcortical brain areas processing external sensory information, reward, cognition, and executive functions. Thus, hedonic controls interact with homeostatic controls to regulate body weight in a flexible and adaptive manner that takes environmental conditions into account. This new conceptual framework has several important implications for the treatment of obesity. Because much of this interactive neural processing is outside awareness, cognitive restraint in a world of plenty is made difficult and prevention and treatment of obesity should be more rationally directed to the complex and often redundant mechanisms underlying this interaction.

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Section: Monitoring Nutrientsmentioning

confidence: 99%

Blaming the Brain for Obesity: Integration of Hedonic and Homeostatic Mechanisms

2017

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“…Rats learned to decrease their resting respiratory rates, an effect that was maintained between sessions and corresponded with a reduction in anxiety-like behavior. Future studies that enhance the ecological validity of operant conditioning procedures could optimize physiological learning (Ramsay and Woods, 2016). Additional studies on controlled animal respiration have employed classical conditioning paradigms (Gallego and Perruchet, 1991; van den Bergh et al, 1995; Nsegbe et al, 1997), or externally induced (“forced”) respiration paradigms using anesthetized and mechanically ventilated preparations, intubated rats, or hypoxic/hypercapnic animals.…”

Section: Future Directions and Proposed Studiesmentioning

confidence: 99%

Hypothesis: Pulmonary Afferent Activity Patterns During Slow, Deep Breathing Contribute to the Neural Induction of Physiological Relaxation

2019

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Control of respiration provides a powerful voluntary portal to entrain and modulate central autonomic networks. Slowing and deepening breathing as a relaxation technique has shown promise in a variety of cardiorespiratory and stress-related disorders, but few studies have investigated the physiological mechanisms conferring its benefits. Recent evidence suggests that breathing at a frequency near 0.1 Hz (6 breaths per minute) promotes behavioral relaxation and baroreflex resonance effects that maximize heart rate variability. Breathing around this frequency appears to elicit resonant and coherent features in neuro-mechanical interactions that optimize physiological function. Here we explore the neurophysiology of slow, deep breathing and propose that coincident features of respiratory and baroreceptor afferent activity cycling at 0.1 Hz entrain central autonomic networks. An important role is assigned to the preferential recruitment of slowly-adapting pulmonary afferents (SARs) during prolonged inhalations. These afferents project to discrete areas in the brainstem within the nucleus of the solitary tract (NTS) and initiate inhibitory actions on downstream targets. Conversely, deep exhalations terminate SAR activity and activate arterial baroreceptors via increases in blood pressure to stimulate, through NTS projections, parasympathetic outflow to the heart. Reciprocal SAR and baroreceptor afferent-evoked actions combine to enhance sympathetic activity during inhalation and parasympathetic activity during exhalation, respectively. This leads to pronounced heart rate variability in phase with the respiratory cycle (respiratory sinus arrhythmia) and improved ventilation-perfusion matching. NTS relay neurons project extensively to areas of the central autonomic network to encode important features of the breathing pattern that may modulate anxiety, arousal, and attention. In our model, pronounced respiratory rhythms during slow, deep breathing also support expression of slow cortical rhythms to induce a functional state of alert relaxation, and, via nasal respiration-based actions on olfactory signaling, recruit hippocampal pathways to boost memory consolidation. Collectively, we assert that the neurophysiological processes recruited during slow, deep breathing enhance the cognitive and behavioral therapeutic outcomes obtained through various mind-body practices. Future studies are required to better understand the physio-behavioral processes involved, including in animal models that control for confounding factors such as expectancy biases.

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“…As a general rule, homeostatic control systems for key biological variables require inputs that both accurately represent the current and also predict the future states of those variables (Ramsay and Woods, 2016). One consequence of this type of arrangement is that the variable in question does not actually have to change for corrective responses to be engaged that keep it stable.…”

Section: Lessons Learned From the Thermoregulatory Systemmentioning

confidence: 99%

Revisiting How the Brain Senses Glucose—And Why

2019

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Glucose-sensitive neurons have long been implicated in glucose homeostasis, but how glucose-sensing information is used by the brain in this process remains uncertain. Here, we propose a model in which 1) information relevant to the circulating glucose level is essential to the proper function of this regulatory system, 2) this input is provided by neurons located outside the blood-brain barrier (BBB) (since neurons situated behind the BBB are exposed to glucose in brain interstitial fluid, rather than that in the circulation), and 3) while the efferent limb of this system is comprised of neurons situated behind the BBB, many of these neurons are also glucose-sensitive. Precedent for such an organizational scheme is found in the thermoregulatory system, which we draw upon in this framework for understanding the role played by brain glucose sensing in glucose homeostasis.

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Physiological Regulation: How It Really Works

Cited by 42 publications

References 45 publications

Blaming the Brain for Obesity: Integration of Hedonic and Homeostatic Mechanisms

Blaming the Brain for Obesity: Integration of Hedonic and Homeostatic Mechanisms

Hypothesis: Pulmonary Afferent Activity Patterns During Slow, Deep Breathing Contribute to the Neural Induction of Physiological Relaxation

Revisiting How the Brain Senses Glucose—And Why

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