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Breathing can be classified into metabolic and behavioral categories. Metabolic breathing and voluntary behavioral breathing are controlled in the brainstem and in the cerebral motor cortex, respectively. This chapter places special emphasis on the reciprocal influences between breathing and emotional processes. As is the case with neural control of breathing, emotions are generated by multiple control networks, located primarily in the forebrain. For several decades, a respiratory rhythm generator has been investigated in the limbic system. The amygdala receives respiratory-related input from the piriform cortex. Excitatory recurrent branches are located in the piriform cortex and have tight reciprocal synaptic connections, which produce periodic oscillations, similar to those recorded in the hippocampus during slow-wave sleep. The relationship between olfactory breathing rhythm and emotion is seen as the gateway to interpreting the relationship between breathing and emotion. In this chapter, we describe roles of breathing in the genesis of emotion, neural structures common to breathing and emotion, and mutual importance of breathing and emotion. We also describe the central roles of conscious awareness and voluntary control of breathing, as effective methods for stabilizing attention and the contents in the stream of consciousness. Voluntary control of breathing is seen as an essential practice for achieving emotional well-being., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Respiratory patterns are influenced and altered by various emotional changes. In the present study, we investigated how respiratory patterns differ from individual to individual during quiet breathing. We examined the State-Trait Anxiety Inventory and various respiratory parameters in 16 healthy male subjects. Tidal volume was significantly larger and respiratory rate (RR) was significantly higher in both the higher trait (HT) and higher state (HS) anxiety groups compared to the lower trait and lower state anxiety groups. Inspiratory (T I ) and expiratory time (T E ) was significantly shorter in both the HT and HS anxiety groups. There was no significant difference in minute ventilation between these two groups. End-tidal CO 2 %, heart rate, and oxygen uptake ([Formula: see text]) also showed no significant differences. V T showed a negative correlation and RR showed a positive correlation with trait scores. T I and T E showed a negative correlation with trait anxiety scores. However, no other respiratory parameter showed any correlation. These results suggest that the respiratory rhythm reflected by RR is affected by the activity generated in the higher center in accordance with the level of trait anxiety during quiet breathing in awake humans.

During exercise, tidal volume initially contributes to ventilatory responses more than respiratory frequency, and respiratory frequency then increases rapidly while tidal volume stabilizes. Dyspnea intensity is also known to increase in a threshold-like manner. We tested the possibility that the threshold of tachypneic breathing is equal to that of dyspnea perception during cycle ergometer exercise (n = 27). Dyspnea intensity was scored by a visual analog scale. Thresholds were expressed as values of pulmonary O 2 uptake at each breakpoint. Dyspnea intensity and respiratory frequency started increasing rapidly once the intensity of stimuli exceeded a threshold level. The thresholds for dyspnea intensity and for occurrence of tachypnea were significantly correlated. An intraclass correlation coefficient of 0.71 and narrow limits of agreement on the Bland-Altman plot indicated a good agreement between these thresholds. These results suggest that the start of tachypneic breathing coincides with the threshold for dyspnea intensity during cycle ergometer exercise.

The precise mechanisms underlying how emotions change breathing patterns remain unclear, but dopamine is a candidate neurotransmitter in the process of emotion-associated breathing. We investigated whether basal dopamine release occurs in the basolateral amygdala (BLA), where sensory-related inputs are received and lead to fear or anxiety responses, and whether D1- and D2-like receptor antagonists affect breathing patterns and dopamine release in the BLA. Adult male mice (C57BL/6N) were perfused with artificial cerebrospinal fluid, a D1-like receptor antagonist (SCH 23390), or a D2-like receptor antagonist ((S)-(-)-sulpiride) through a microdialysis probe in the BLA. Respiratory variables were measured using a double-chamber plethysmograph. Dopamine release was measured by an HPLC. Perfusion of (S)-(-)-sulpiride in the BLA, not SCH 23390, specifically decreased respiratory rate without changes in local release of dopamine. These results suggest that basal dopamine release in the BLA, at least partially, increases respiratory rates only through post-synaptic D2-like receptors, not autoreceptors, which might be associated with emotional responses., (Copyright © 2014 Elsevier B.V. All rights reserved.)

It remains an open question whether placebo/sham acupuncture, in which the needle tip presses the skin, can be used as a placebo device for research on pain. We compare the analgesic effect of the skin-touch placebo needle with that of the no-touch placebo needle, in which the needle tip does not touch the skin, in a double-blind crossover manner including no-treatment control in 23 healthy volunteers. The subjects received painful electrical stimulation in the forearm before and during needle retention to the LI 4 acupoint and after the removal of the needle and rated pain intensity using a visual analogue scale. We found no significant difference in analgesic effects among the skin-touch placebo needle, no-touch placebo needle, and no-treatment control at every point before, during, and after the treatments (p > 0.05). The results indicate that the skin-touch placebo needle can be used as a placebo device in clinical studies on pain.

Background: Whether acupuncture treatment employing multiple penetrating, skin-touch placebo, or no-touch placebo needles designed for double blinding actually do blind practitioners and patients has not been investigated. We aimed to investigate this question., Subjects: 120 patients with functional neck/shoulder stiffness but in otherwise healthy condition were randomly assigned to a treatment using four penetrating, four skin-touch placebo, or four no-touch placebo needles. Each of six acupuncturists applied four needles to four acupoints in the neck/shoulder of 20 patients. Acupuncturists and patients were asked to guess the treatment mode and their confidence in their guesses on 100 mm visual analog scales., Results: The kappa coefficients between practitioner guesses and treatment type and between patient guesses and treatment type were 0.15 and 0.44, respectively. The median score of practitioner confidence was 46.8, and no significant difference in confidence between correct and incorrect guesses was revealed for any treatment. The median score of patient confidence for correct guesses was 77.6. The kappa coefficient between practitioner and patient guesses was 0.06., Conclusions: The practitioners were blinded to the nature of treatment using the same multiple needles, but patient blinding was insufficient. Further improvement is necessary to achieve satisfactory patient blinding with these acupuncture needles.

Olfaction is dependent on respiration for the delivery of odorants to the nasal cavity. Taking advantage of the time-locked nature of inspiration and olfactory processing, electroencephalogram dipole modeling (EEG/DT) has previously been used to identify a cascade of inspiration-triggered neural activity moving from primary limbic olfactory regions to frontal cortical areas during odor perception. In this study, we leverage the spatial resolution of functional magnetic resonance imaging (fMRI) alongside the temporal resolution of EEG to replicate and extend these findings. Brain activation identified by both modalities converged within association regions of the orbitofrontal cortex that were activated from approximately 150-300 ms after inspiration onset. EEG/DT was additionally sensitive to more transient activity in primary olfactory regions, including the parahippocampal gyrus and amygdala, occurring approximately 50 ms post-inspiration. These results provide a partial validation of the spatial profile of the olfactory cascade identified by EEG source modeling, and inform novel future directions in the investigation of human olfaction., (Copyright © 2014 Elsevier B.V. All rights reserved.)

There is some evidence that signals coming from both arms are used to determine the perceived position and movement of one arm. We examined whether the sense of position and movement of one (reference) arm is altered by increases in muscle spindle signals in the other (indicator) arm in blindfolded participants (n = 26). To increase muscle spindle discharge, we applied 70-80 Hz muscle vibration to the elbow flexors of the indicator arm. In a first experiment, proprioceptive illusions in the vibrated reference arm in a forearm position-matching task were compared between conditions in which the indicator arm elbow flexors were vibrated or not vibrated. We found that the vibration illusion of arm extension induced by vibration of reference arm elbow flexors was reduced in the presence of vibration of the indicator elbow flexors. In a second experiment, participants were asked to describe their perception of the illusion of forearm extension movements of the reference arm evoked by vibration of reference arm elbow flexors in response to on/off and off/on transitions of vibration of non-reference arm elbow flexors. When vibration of non-reference arm elbow flexors was turned on, they reported a sensation of slowing down of the illusion of the reference arm. When it was turned off, they reported a sensation of speeding up. To conclude, the present study shows that both the sense of limb position and the sense of limb movement of one arm are dependent to some extent on spindle signals coming from the other arm.

As a result of recent progress in brain imaging techniques, a number of studies have been able to identify anatomical correlates of various emotions (Pujol et al., 2013; Tettamanti et al., 2012; van der Zwaag et al., 2012). However, emotions are not solely a phenomenon within the brain-they are also composed of body responses. These include autonomic and behavioral responses, such as changes in heart rate, blood pressure, skin conductance, and respiration. Among these physiological responses, respiration has a unique relationship to emotion. While the primary role of respiration concerns metabolism and homeostasis, emotions such as disgust, anger, and happiness also influence respiratory activities (Boiten et al., 1994). While respiratory change that accompanies emotions can occur unconsciously, respiration can also be voluntarily altered associating with an activation of the motor cortex. There may be no physiological expression for the association between the three areas of the brain that regulate respiration: the brainstem, the limbic system, and the cerebral cortex. The brainstem works to maintain homeostasis, the limbic system is responsible for emotional processing, and the cerebral cortex controls intention. Investigating the interaction between these brain regions may lead to an explanation about why they are so widely dispersed in the brain, despite their common role in the regulation of respiration. In this chapter, we review our findings on breathing behavior and discuss the mechanisms underlying the relationship between emotion and respiration., (© 2014 Elsevier B.V. All rights reserved.)

The anatomical factors involved in upper airway closure of obstructive sleep apnea (OSA) have been established. However, the mechanisms of repetitive OSA are not well understood. We found that dorsomedial medullary 5-HT2 receptor activity is compensated for by hypercapnia and elicits the immediate onset of poikilocapnic hypoxic ventilatory airway responses. Therefore, the aim of this study was to test the hypothesis that hypercapnia compensates for the immediate onset of poikilocapnic hypoxic ventilatory airway responses induced by dorsomedial medullary 5-HT2 receptors. Adult male mice (C57BL/6N) were intraperitoneally anesthetized with pentobarbital sodium. Microdialysis probes were inserted into the dorsomedial medulla oblongata of the mice. The mice were placed in a double-chamber plethysmograph and were allowed to acclimatize and recover from anesthesia. Mice were then exposed to hypercapnic hypoxic gases (7 % O2/5 % CO2 in N2) with or without 5-HT2-antagonist (10(-5) M LY-53857) perfusion. Respiratory curves through the head and body chambers were recorded to measure ventilatory airway variables. Extracellular fluid was collected every 5 min for HPLC analysis of 5-HT concentration. Hypercapnic hypoxia elicited neither delayed onset of ventilatory augmentation nor immediate airway narrowing with dorsomedial medullary 5-HT2 antagonism. Hypoxic polypnea was shifted downward. The increases in dorsomedial medullary 5-HT release and ventilatory volume were not affected with or without 5-HT2 activity. In conclusion, the onset of poikilocapnic hypoxic ventilatory airway responses mediated via dorsomedial medullary 5-HT2 activity is compensated for by hypercapnia. Maintenance of PCO2 level and CO2 responsiveness, especially with lowered 5-HT2 activity, may be important for preventing repetitive OSA.

There is evidence that impaired human cognitive abilities are reflected by loss of olfactory abilities. Declining olfactory perception may be a biomarker for impairment of cognitive function and of impending neurogenerative disorders. As olfactory perception may differ between culture and ethnic group, we sought to confirm this relationship with Japanese participants. In this study, we examined possible relationships between age and olfactory abilities in healthy Japanese subjects (control subjects) over a wide range of ages and compared this relationship with that observed in three neurodegenerative disorders; patients with Parkinson's disease (PD), Type 1 myotonic dystrophy (DM1) and Alzheimer's disease (AD). In control subjects, both threshold and recognition abilities decreased with age. Ability to detect odors was generally intact in most control subjects, however, we found that the abilities of individuals in the three different patient populations to recognize odors were impaired relative to control subjects. All three types of patients exhibited decreased or impaired odor-recognition compared with age-matched controls. Previous studies showed the causes of olfactory impairments in PD and AD patients were attributable to pathological changes and MRI signal abnormalities in limbic areas, including the amygdala (AMG), entorhinal cortex (ENT), hippocampus (HI), and orbitofrontal cortex (OFC). Another study reported that DM1 patients have bilateral lesions in anterior temporal areas, including the subcortical white matter, AMG, ENT and insula. Our findings underscore the need to pay careful attention to significant decreases of odor identification abilities caused by diverse forms of abnormal brain function, especially in the AMG, ENT and HI., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

Background: Vibration-induced finger flexion reflex (VFR) is inhibited with acupuncture to TE 5 or LI 4 at the skin innervated by the radial nerve., Objective: The aim of this study was to determine if acupoints in regions innervated by the radial nerve are specific to inhibit VFR., Materials and Methods: This experiment was performed using a crossover design with 3 acupuncture groups (needle insertion to the right LU 11, PC 9, or SI 1) and a control group (no needle treatment). Each acupoint was randomly needled on separate days. Ten healthy volunteers were recruited for this study. VFR was induced by applying vibration on the volar side of the right middle fingertip. An acupuncture needle was inserted in the acupoint and retained for 5 minutes. For the main outcome measure, maximum finger flexion force (MFFF) was measured during vibration and was compared among four groups., Results: MFFFs in the acupuncture groups were significantly lower ( p <0.05) than that in the control group. However, no significant difference was observed in MFFFs in the three intervention groups after acupuncture to LU 11, PC 9, and SI 1., Conclusions: Acupuncture to the right LU 11, PC 9, or SI 1 point inhibited the ipsilateral VFR, which suggests that afferent inputs from the radial nerve with needle insertion were not specific, compared with those from the median and ulnar nerves to suppress neuronal activities in the VFR reflex circuits.

Background: The use of positive end-expiratory pressure (PEEP) is a practical intervention to improve oxygenation during anesthetic management; however, the underlying mechanisms have not been elucidated., Methods: Parameters of ventilator settings and results of arterial blood gas analyses were collected from medical records of adult patients undergoing surgery under general anesthesia with pressure-controlled ventilation in our hospital from January 2009 to March 2010. We analyzed the changes in dynamic compliance (Cdyn) and alveolar-arterial oxygen difference (A-aDo2)., Results: A total of 139 patients were enrolled; anesthesia was maintained with sevoflurane in 82 patients, and with propofol in 57 patients. After the application of PEEP, significant decreases in A-aDo2 were accompanied with significant increases in Cdyn under sevoflurane anesthesia. However, significant decreases in A-aDo2 were not always accompanied by significant increases in C(dyn) under propofol anesthesia., Conclusions: These results suggest that the mechanisms for improved oxygenation by PEEP under sevoflurane anesthesia are different from those under propofol anesthesia. The improved oxygenation after the application of PEEP under sevoflurane anesthesia is mainly due to reduction of atelectasis, whereas reduction of atelectasis as well as reduction of intrapulmonary shunt is associated with the improved oxygenation after the application of PEEP under propofol anesthesia.

Automatic regulation of tidal volume (VT) maintains CO2 homeostasis when spontaneous respiratory rhythm is replaced with a cortically triggered rhythm. We examined whether automatic regulation of respiratory frequency (fR) could maintain CO2 homeostasis at rest if the VT is cortically designated in experiments performed in 21 conscious humans. First, volitionally controlled fR at levels lower than baseline resulted in a larger VT, maintaining end-tidal CO2 fraction constant at eupneic levels. However, when fR was volitionally controlled at levels higher than baseline, end-tidal CO2 fraction decreased unexpectedly. Next, when the VT was volitionally constrained but fr was freely chosen, end-tidal CO2 fraction decreased. The present study revealed some limitations in the control of CO2 homeostasis by automatic regulation of fR, probably because respiratory rhythm is susceptible to non-metabolic factors. This study also showed the importance of automatic regulation of VT in maintaining CO2 homeostasis at rest. Nevertheless, automatic regulation of VT was incomplete when fR was volitionally imposed at high levels., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Previously, we undertook simultaneous recording of ventilation and pulmonary gas exchange in mice and revealed that dopamine D(2) receptors participate in exercise hyperpnoea via behavioural control of ventilation with unchanged pulmonary gas exchange. Here, we examined the hypothesis that D(1) receptors also contribute to exercise hyperpnoea using a D(1) receptor antagonist (SCH 23390; SCH) that crosses the blood-brain barrier, with the same recording technique and protocol as in the previous study. The respiratory responses of mice injected with saline or SCH (50 μg (kg body weight)(-1), i.p.) were compared during constant-load exercise at 6 m min(-1). Each mouse was set in an airtight treadmill chamber equipped with a differential pressure transducer and open-circuit system with a mass spectrometer. At rest, SCH-injected mice had significantly reduced respiratory frequency, minute ventilation and pulmonary gas exchange compared with saline-injected mice. Ventilation during hyperoxic gas inhalation and hypercapnic ventilatory responses between groups were similar. Abrupt increases and sequential declines to the steady-state level were produced by treadmill exercise in both groups of mice. Treatment with SCH lowered the increased levels of respiratory frequency, tidal volume and minute ventilation during the steady state, as well as reducing the O(2) uptake, CO(2) output and body temperature throughout treadmill exercise. These data suggest that D(1) receptors contribute to a resting ventilation level and exercise hyperpnoea during the steady state in parallel with metabolic changes. Notably, the metabolic control of D(1) receptors was important for maintenance of the steady state, and D(1) receptors in hypothalamic nuclei could be involved in this modulation.

We have shown that constant-load treadmill exercise in mice produces an abrupt ventilatory increase to a maximal level at exercise onset. We examined what caused this abrupt response. We measured ventilation during 30-min constant-load exercise on a treadmill, below the lactate threshold, in conscious mice. Video analysis showed that hyperpnoea started before locomotion began. Incremental changes in speed did not further increase ventilation during the early phase of exercise. Next, we measured ventilatory responses to a sudden movement of the treadmill belt on which the mice were kept in a stationary position by a mesh cover. Hyperpnoea started concurrently with the sudden belt movement. In the absence of locomotion, ventilation increased to the extent reached during exercise hyperpnoea. Finally, the abrupt response showed plasticity but was attenuated by experience. The present study shows the importance of factors independent of limb movements in the hyperpnoeic response during the early phase of treadmill exercise in mice., (Copyright © 2012 Elsevier B.V. All rights reserved.)

No previous report has described whether information regarding an odor used in aromatherapy has placebo effects. We investigated whether placebo analgesia was engendered by verbal information regarding the analgesic effects of an odor. Twelve of 24 subjects were provided with the information that a lavender odor would reduce pain (informed), whereas the other 12 subjects were not (not-informed). Concurrent with respiration recording, the subjects were administered a lavender-odor or no-odor treatment during application of painful stimulation to the forefinger. The subjects reported their experience of pain and its unpleasantness on a visual analogue scale after the painful stimulation. The lavender-odor treatment significantly alleviated pain and unpleasantness compared with the no-odor treatment in the informed (P < 0.01) and not-informed groups (P < 0.05). The no-odor treatment in the informed group significantly alleviated pain and unpleasantness compared with both the no-odor and lavender-odor treatments in the not-informed group (P < 0.05). Rapid and shallow breathing induced by the painful stimulation became slow and deep during the lavender-odor and no-odor treatments in both groups. Information regarding a lavender odor, the lavender odor itself, and slower breathing contributed to reduced perceptions of pain and unpleasantness during painful stimulation, suggesting that placebo effects significantly contribute to analgesia in aromatherapy.

We studied the influence of false proprioceptive information generated by arm vibration and false visual information provided by a mirror in which subjects saw a reflection of another arm on perception of arm position, in a forearm position-matching task in right-handed subjects (n = 17). The mirror was placed between left and right arms, and arranged so that the reflected left arm appeared to the subjects to be their unseen right (reference) arm. The felt position of the right arm, indicated with a paddle, was influenced by vision of the mirror image of the left arm. If the left arm appeared flexed in the mirror, subjects felt their right arm to be more flexed than it was. Conversely, if the left arm was extended, they felt their right arm to be more extended than it was. When reference elbow flexors were vibrated at 70-80 Hz, an illusion of extension of the vibrated arm was elicited. The illusion of a more flexed reference arm evoked by seeing a mirror image of the flexed left arm was reduced by vibration. However, the illusion of extension of the right arm evoked by seeing a mirror image of the extended left arm was increased by vibration. That is, when the mirror and vibration illusions were in the same direction, they reinforced each other. However, when they were in opposite directions, they tended to cancel one another. The present study shows the interaction between proprioceptive and visual information in perception of arm position.

Corticotropin-releasing factor (CRF) is a neuropeptide that mediates neuroendocrine, autonomic, and behavioral processes associated with the stress response. CRF-containing fibers and receptors are found in various regions of the central nervous system including the spinal cord. Here, we report excitatory effects of CRF on sympathetic preganglionic neurons in the intermediolateral cell column (IML) of in vitro spinal cord preparations from newborn rats. We also examine the receptor subtypes that are involved in the CRF effects. Application of CRF significantly depolarized the IML neurons and increased the frequency of excitatory postsynaptic potentials (EPSPs) in the IML neurons. These effects were blocked by the CRF receptor 1 antagonist, antalarmin. Menthol, a transient receptor potential channel M8 agonist, depressed EPSPs enhanced by CRF. Our findings suggested that CRF depolarized the IML neurons via direct postsynaptic action and CRF-affected interneurons located in the spinal cord send EPSPs to IML neurons. These excitatory effects of CRF may be caused through CRF1 receptors but not CRF2 receptors., (Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.)

Breathing plays an important role in perception of odors and the experience of emotions. We used the dipole tracing method to analyze brain areas related to odor-induced autobiographical memory and emotions estimated from averaged electroencephalograms triggered by inspiration onset during odor presentation. Odor stimuli were perfumes subjects named that elicited a specific, pleasant and personal memory as well as two pleasant odors for controls. The perfumes induced specific emotional responses during memory retrieval, arousal level of the memory, feelings of pleasantness and a sense of familiarity with the odor. Respiration measurement indicated that tidal volume increased and respiratory frequency decreased during presentation of perfume stimuli, showing a deep and slow breathing pattern. Throughout the olfactory stimulation, electroencephalograms and respiration were simultaneously recorded. In the averaged potentials, low frequency oscillation was phase-locked to inspiration. Dipole analysis showed that perfumes activated more widespread areas of the right parahippocampal cortex and converged in the right amygdala compared to control odors. Slow breathing synchronized with odor-induced autobiographical memory and emotions may be subconsciously stored in the parahippocampal cortex and amygdala., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

An important feature of olfactory perception is its dependence on respiratory activity. By inspiration, olfactory information ascends directly to olfactory-related limbic structures. Therefore, every breath with odor molecules activates these limbic areas associated with emotional experience and memory retrieval. We tested whether odors associated with autobiographical memories can trigger pleasant emotional experiences and whether respiration changes during stimulation with these odors. During presentation of odors related to autobiographical memories and control odors, we measured minute ventilation, tidal volume, respiratory frequency, O2 consumption, and end tidal CO2 concentration. Findings showed that autobiographical memory retrieval was associated with increasing tidal volume and decreasing respiratory frequency more than during presentation of control odors. Subjective feelings such as emotional arousal during retrieval of the memory, arousal level of the memory itself, or pleasantness and familiarity toward the odor evoked by autobiographical memory were more specific emotional responses compared with those related to control odors. In addition, high trait anxiety subjects responded with a stronger feeling of being taken back in time and had high arousal levels with tidal volume increases. We discussed assumptions regarding how deep and slow breathing is related to pleasantness and comfortableness of an autobiographical memory.

Studies of empathy show that seeing another person in pain, fear or disgust elicits the same brain activations associated with pain, fear or disgust in oneself. Our interest is to know whether respiratory change can be observed in empathy, that is, whether respiration can be altered when observing emotions in others. A discomfort associated with respiration can be breathlessness. We investigated respiratory pattern and metabolic response during observation of a breath-holding subject. We found that breathlessness occurred in participants who observed breath-holding in another person. It is interesting to note that observers felt more breathlessness after breath-holding ended with an increase in respiratory rate consistent with the breath-holder's respiratory pattern. In addition, observers with high trait anxiety felt more breathlessness accompanied with an increase in respiratory rate. An increase in respiratory rate may be involved in the perception of breathlessness, in addition to the effect of observing breath-holding, indicating shared negative emotion., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Dopamine is related to behaviour (including arousal, motivation and motor control of locomotion), and its turnover in the brain is increased during exercise. We examined the hypothesis that dopamine D(2) receptors contribute to exercise hyperpnoea via central neural pathways using the D(2)-like receptor antagonist, raclopride. We simultaneously measured ventilation and pulmonary gas exchange for the first time in mice. Mice injected with saline and raclopride (2 mg (kg body weight)(-1); i.p.) were compared for respiratory responses to constant-load exercise at 6 m min(-1). Each mouse was set in an airtight treadmill chamber. In the resting state, raclopride-treated mice had reduced respiratory frequency (f(R)) and minute ventilation (V) compared with saline-treated mice, but arterial P(CO(2)) and pulmonary gas exchange were not affected, showing that alveolar ventilation was maintained. Inhalation of hyperoxic gas maintained V in saline-treated mice, and hypercapnic ventilatory responses between the two groups were similar. Treadmill exercise produced an abrupt increase in V to a maximal level within 1 min and declined to a steady-state level in both groups. Raclopride-treated mice had reduced f(R) and V compared with saline-treated mice during steady states, but showed a similar increase in f(R) and V at exercise onset. Minute ventilation in the steady state was controlled, along with the increase in pulmonary O(2) uptake in both groups, but was lowered in raclopride-treated mice. Thus, D(2) receptors participate in resting breathing patterns to raise f(R) and exercise hyperpnoea in the steady state, probably through behavioural control and not central motor command, at exercise onset.

We examined two male patients (64 and 70 years old) with rapid eye movement sleep behaviour disorder (RBD) using cognitive tests, myocardial (123)I-metaiodobenzylguanidine (MIBG) scintigraphy, and dopamine positron emission tomography (PET) imaging. One patient had impaired social cognition and decision-making skills and reduced MIBG reuptake, and dopamine PET imaging indicated striatal terminal loss. The other patient had normal social cognition and reduced MIBG reuptake, but no abnormalities were detected by dopamine PET imaging. Both patients reported constipation. This study supports the hypothesis by Braak et al. [Mov Disord 2006;21:2042-2051] that impairment of the amygdala and striatum occurs at the same stage as α-synucleinopathy, and the findings suggest that autonomic dysfunctions such as reduced MIBG reuptake and constipation are the earliest symptoms of RBD. Detailed neuropsychological and radiological assessments of these 2 cases revealed that idiopathic RBD could develop in various clinical situations and include cognitive and autonomic changes. Further longitudinal studies with larger sample sizes will help understand the neuropsychology and pathophysiology of RBD., (Copyright © 2011 S. Karger AG, Basel.)

Respiratory rhythm is susceptible to behavioral influences including emotions. Since laboratory dyspnea induces negative emotions, we examined whether tachypneic breathing occurs in relation to perception of dyspnea during CO(2) rebreathing (n=21). Dyspnea intensity scored by a visual analog scale and respiratory frequency started to increase rapidly once the intensity of the stimuli exceeded a threshold for the end-tidal CO(2) fraction. The thresholds for dyspnea and respiratory frequency were similar (7.5±0.1% and 7.6±0.2% of the end-tidal CO(2) fraction, respectively), while the threshold for tidal volume (8.0±0.2%), when the tidal volume had stabilized, was significantly higher than the thresholds for dyspnea (p<0.01) and respiratory frequency (p<0.05). A positive correlation was found between the thresholds for dyspnea and respiratory frequency (r=0.81, p<0.001), and these thresholds showed good agreement on a Bland-Altman plot. These findings suggest that the start of tachypneic breathing is coupled with the threshold for dyspnea., (Copyright © 2011 Elsevier B.V. All rights reserved.)

This study aimed to test whether type 1 myotonic dystrophy (DM1) patients who have a lower sensitivity to emotional facial expressions have an abnormal olfactory threshold or recognition level. We measured DM1 patients' performances in an olfactory acuity test and respiratory responses to odor stimuli, and compared their results to those of healthy controls (HCs). We found that DM1 patients exhibited a significantly reduced odor detection sensitivity compared with that in HCs. Three out of seven DM1 patients exhibited impaired odor recognition, while other four patients had significantly lower odor recognition compared with HCs. Even when patients were able to identify the type of odor, the levels of pleasantness they reported experiencing in response to a pleasant odor were significantly lower than those reported by HCs. These subjective data in DM1 patients were reflected in the respiratory responses (RRs). In the current study, one patient showed impairments in both odor detection and odor recognition. Abnormalities of the olfactory limbic areas might have been the cause of the olfactory impairments observed in the DM1 patients., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

The amygdala is an important higher regulatory center of the autonomic nervous system, involved in respiratory and cardiovascular control, and it also plays a role in the formation of emotions. Corticotropin-releasing factor (CRF) is a neuropeptide involved in stress responses. We have examined the effects of CRF on the spontaneous burst activity in the piriform-amygdala complex of rat brain preparations in vitro. Limbic-brainstem-spinal cord preparations of 0- to 1-day-old Wistar rats were isolated under deep ether anesthesia, and were superperfused in a modified Krebs solution. Bath application of 50nM CRF substantially increased the frequency of burst activity in the piriform-amygdala complex, whereas this polypeptide exerted only minor effects on C4 inspiratory activity. The excitatory effect of CRF on the amygdala burst was effectively blocked by the CRF1 antagonist, antalarmin, but not the CRF2 antagonist, astressin-2B, suggesting that CRF1 mediated the excitatory effect. The spatio-temporal pattern of the burst activity according to optical recordings was basically identical to the controls; the burst activity initially appeared in the piriform cortex and then propagated to the amygdala. The present experimental model could be useful for the study of role of the limbic system, including the amygdala, in stress responses., (Copyright © 2011 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.)

We tested the hypothesis that fasting affects hypoxic ventilatory responses through metabolic changes via histamine H1 receptors. Wild-type (WT) and histamine H1 receptor knockout (H1RKO) mice were studied in fed and fasted states. In the fed WT, hypoxic-gas exposure elicited an increase and a subsequent decline in ventilation (hypoxic ventilatory decline or HVD). HVD was influenced by fasting in breathing pattern with metabolic rate. Fasting elicited hypoglycemia, a drop in R, and increases in free fatty acid and ketone bodies in the serum. In H1RKO, HVD was blunted in the fed state, but it appeared in the fasted state. There was a minimal drop in R following fasting and a low triglyceride concentration. Thus, fasting affects HVD through a change in energy mobilization from glucose to lipid metabolism. Histamine H1 receptors are involved in HVD during fed and fasted states, resulting in adaptation to the environmental conditions.

Menthol is known as an agonist for cold-sensitive transient receptor potential channels (TRPM8) and also as a direct modulator of GABA channels. We examined the effects of menthol on respiratory rhythm generation in the brainstem-spinal cord preparations isolated from newborn rats. Menthol decreased respiratory rhythm dose-dependently (0.1-1 mM). Effects of menthol were reversed by the GABAA antagonist, bicuculline. Menthol caused pronounced reduction in the driving potential of pre-inspiratory but not inspiratory neurons. Expression of the TRPM8 channel protein was not detected in the respiratory related region of the rostral ventrolateral medulla by immunohistochemistry. The results suggest that the potent inhibitory action of menthol on burst generation of pre-inspiratory neurons is because of direct activation of tonic GABA channels by menthol.

Objective: To understand the functional roles of brain regions related in the auditory spatial localization, we recorded auditory event-related potentials (ERPs) and estimated their source generators using the dipole tracing method., Methods: Target sound stimuli perceived as coming from two directions (-90 degrees, +90 degrees where 0 degrees was straight behind the subject within the azimuth in the interaural plane) were randomly presented with two distracter stimuli for providing difficulty of detection. The distracter stimuli were 75 degrees behind the target stimuli (easy task) and 45 degrees behind the target stimuli (difficult task)., Results: Compared with the passive listening tasks, distinct potentials appeared in the easy task at the early (110-150 ms: N1-late) time windows of ERPs and in the difficult task at the late (450-800 ms: slow wave, SW) time windows of ERPs. Dipoles were estimated to be at the posterior auditory cortex, precuneus and thalamus for N1-late, and the middle/inferior frontal gyrus, anterior region of superior temporal gyrus and parahippocampal gyrus for SW for both tasks., Conclusions: Difficulty of sound localization may affect brain function related to analyzing features of the spatial cue, eventually identifying the spatial location, and attention., Significance: Brain regions responsible for sound localization may show different activity patterns depending on the functional roles of each brain region., (2010 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)

Experiments were carried out on blindfolded human subjects to study the contribution of proprioceptive inputs from both arms in a forearm position matching task. Blindfolded matching accuracy was compared with accuracy when the subject could see their indicator (matching) arm, when they used a dummy arm for matching, and when they looked at a mirror image of the matching arm. The position of the mirror had been arranged so that the image of the indicator arm coincided with the position of the reference arm. None of these conditions significantly altered the matching errors. When reference elbow flexors were vibrated at 70-80 Hz, the illusion of extension of the vibrated arm reported by blindfolded subjects was significantly reduced by vision of the mirror image of the indicator arm or when using the dummy arm. It was concluded that visual information about the position of the indicator arm, or the apparent position of the reference arm, could reduce the size of the kinaesthetic illusion from vibration, but not abolish it. In a second experiment, subjects indicated, by tracking with their vibrated arm, the illusion of forearm extension evoked by elbow flexor vibration. It was found that the perceived speed of extension could be reduced by moving the indicator into extension and increased by moving it into flexion. These experiments demonstrate the importance for the matching process of the input provided by the indicator arm. Such a conclusion may help to explain some apparent discrepancies between observations made on position sense using one-arm and two-arm tasks. More broadly, this paper provides support for the idea that aspects of proprioceptive inputs from both arms are processed conjointly, as part of a strategy for use of the two hands as a single instrument in certain skilled tasks.

Background: Vibration-induced finger flexion reflex (VFR) in the upper extremity is inhibited by needle insertion acupuncture to the large intestine 4 (LI4) at the hand. This claim has a limitation because the inhibitory effect is deduced only from reduction in the maximum finger flexion (FF) force during the tonic flexion reflex by vibratory stimulation after acupuncture., Methods: The study was a crossover design with two conditions-acupuncture and control-to which 16 healthy volunteers were subjected. VFR in the upper extremity was induced by applying vibratory stimulation on the volar side of the middle fingertip of the right hand, before and after acupuncture at the right LI4 in 16 healthy volunteers. We measured the area under the curve (AUC) of finger flexion force and surface electromyogram (EMG) in the flexor muscles, in addition to the maximum FF force during vibratory stimulation. We compared AUC, surface EMG and maximum FF force in the acupuncture condition with those in the control condition. We also estimated the correlation between AUC, surface EMG and maximum FF force., Results: AUC, surface EMG and maximum FF force were significantly reduced (p <0.01) after acupuncture compared with those of the control group. A strong correlation was observed in maximum FF force versus AUC (r=0.98, p <0.01) and surface EMG (r=0.77, p <0.01)., Conclusions: Acupuncture at ipsilateral LI4 inhibited tonic activities in the finger flexor muscles during VFR, which suggests that afferent input with needle penetration has inhibitory effect on the motor neuronal activities in the reflex circuits of VFR.

Respiration is essential for smell perception. Previously we found that 8-12-Hz cortical rhythms were phase-locked to inspiration onset during the presentation of odor stimuli; this is referred to as inspiration phase-locked alpha band oscillation (I-alpha). Generators of I-alpha estimated with a dipole fitting model were found in the piriform, the entorhinal cortex (ENT), the amygdala (AMG), the hippocampus (HI) and the orbitofrontal cortex (OFC). Such olfactory perception is said to occur via the orthonasal olfaction route. Another route is the retronasal olfaction route. In this study, we investigated the link between respiration phase and retronasal olfactory perception. Electroencephalograph (EEG) and respiratory flows (separately measured with mouth and nose) were simultaneously recorded during stimulation of subjects' tongues with liquids of chocolate, sucrose and water. The percentage of subjects correctly identifying the chocolate taste was higher when subjects were asked to breathe through the nose than when they were breathing through the mouth. In the averaged EEGs triggered by the onset of expiration measured from the flow through the nose, a 8-12-Hz oscillation was observed. Generators of this potential were found in the left ENT, HI, AMG and OFC in the order of milliseconds after expiration onset. Perception of retronasal olfaction is dependent on expiration, and combining retronasal olfactory information with gustatory information and somatosensation enable us to identify flavors when drinking and feeding.

It may not be easy to present to beginners CO(2) and O(2) having the opposite effect on respiration, using the conventional diagram explaining negative feedback. In the new diagram we developed, the "cause", its facilitating effect on the "result", the facilitating and inhibiting noises on the "result", the current magnitude of the "result", the set-point, their comparison, and feedback effect on the "cause" are all clearly illustrated. For example, the engine RPM is the "cause", increase in speed is the "result", a downhill slope is the facilitating noise, and an uphill slope is the inhibiting noise. By having direction in the "result", such as INCREASE in speed, INCREASE in O(2), and DECREASE in CO(2), the same diagram could be used to present CO(2) and O(2) having the opposite effect on respiration.

The airway and ventilatory responses in mice elicited by the inhalation of hypercapnic or hypoxic gas mixtures were investigated by a microdialysis technique, 5-HT release analysis and double-chamber plethysmography with or without 5-HT2 receptor activity in the dorsomedial medulla oblongata (DMM). Hypercapnia elicited compensatory airway dilation and additive ventilatory augmentation to 5-HT2 receptor activity in the DMM. Hypoxia mediated immediate onset of hypoxic hyperventilation and airway dilation, and subsequent hypoxic ventilatory decline. Chemical control of the airway and ventilatory responses mediated via 5-HT2 receptors in the DMM are reviewed.

Breathing is primarily involuntary and generated for metabolic and homeostatic purposes in the brainstem. However, changes in breathing can be voluntary or altered by various environmental stimuli. Therefore, breathing is categorized as either metabolic or behavioral. Breathing that changes during various emotions is a subcategory of behavioral breathing due to the strong connection it has with emotion and behavior. The limbic system, located in the medio-temporal lobe of the brain, is the center that governs emotion.

Central histamine has crucial roles in circadian rhythm, ventilation, and the balance of energy metabolism via H1 receptors. We focused on the variation in ventilatory responses to hypoxia between light and dark periods, and the requirement of histamine H1 receptors for the circadian variation, using wild-type (WT) and histamine H1 receptor-knockout (H1RKO) mice. In WT mice, minute ventilation (V(E)) during hypoxia was higher in the dark period than in the light period. In H1RKO mice, changes in V(E) between photoperiods were minimal because V(E) increased relative to VO(2) (particularly in the light period). H1RKO mice showed metabolic acidosis, and increased levels of ketone bodies in blood during the light period. These data suggested that changes in V(E) during hypoxia vary between light and dark periods, and that H1 receptors have a role in the circadian variation in V(E) through control of acid-base status and metabolism in mice.

The objective of this study was to explore characteristics of breathing pattern and anxiety levels of athletes involved in women's rhythmic gymnastics. We tested 13 college level female rhythmic gymnasts (GG) from the same team, and compared their results with those of 26 non-athlete medical students (RG). Subjects were tested by a CO(2) rebreathing method using a gas mixture of 5% CO(2) and 95% O(2). The trait and state anxiety levels of the subjects were tested using the Spielberger's trait and state anxiety inventory (STAI). GG was significantly higher in both trait and state anxiety levels and, in comparison with RG, they also exhibited significantly less variance in the % contribution of change in frequency to the overall increase in minute ventilation during CO(2) rebreathing when compared to RG. Furthermore, there was a positive correlation between both trait and state anxiety and % contribution of frequency change in the RG.

Olfaction is a unique sensory modality. Odor molecules reach olfactory receptors by inspiration, and odor information projects directly to limbic structures not through the thalamus. Odor stimuli thus induce respiratory changes, and simultaneously induce emotion and memory recognition via stimulation of olfactory-related limbic structures. We review the relations between respiration and olfaction, and between brain rhythm and respiration from our studies in normal subjects and in patients with Parkinson's disease who had been reported to have olfactory impairment.

The intermediolateral cell column (IML) of the spinal cord is an important area where sympathetic impulses propagate to peripheral sympathetic organs. ANG II and aldosterone are important components of the renin-angiotensin-aldosterone system (RAAS), which activate the sympathetic nervous system. Each is partly synthesized in the brain and plays a paracrine role in the regulation of blood pressure independently of RAAS in the periphery. Our purpose in the present study was to clarify the contributions of sympathetic preganglionic neurons in the IML (IML neurons) and the effects of ANG II and aldosterone on the sympathetic nervous system. To examine responses to ANG II and aldosterone, we intracellularly recorded 104 IML neurons using a whole cell patch-clamp technique in spinal cord slice preparations. IML neurons were classified into two types: silent and firing. Both neuron types were significantly depolarized by ANG II, and candesartan inhibited this depolarization. After pretreatment with TTX, firing neurons (but not silent neurons) were significantly depolarized by ANG II. Aldosterone significantly increased the number of excitatory postsynaptic potentials (EPSPs) in both neuron types, but this response disappeared after pretreatment with TTX. ANG II and aldosterone had no synergistic effects on the IML neurons. The silent neurons had large cell soma, and many more dendrites than the firing neurons. These results suggest that ANG II acts presynaptically and postsynaptically in IML neurons, while aldosterone acts mainly presynaptically. Thus, the physiological effects of these substances are likely to be transmitted via specific membrane receptors of IML and/or presynaptic neurons.

The dorsomedial medulla oblongata (DMM) includes the solitary tract nucleus and the hypoglossal nucleus, to which 5-HT neurons project. Effects of 5-HT in the DMM on ventilatory augmentation and airway dilation are mediated via 5-HT2 receptors, which interact with the CO(2) drive. The interaction may elicit cycles between hyperventilation with airway dilation and hypoventilation with airway narrowing. In the present study, effects of 5-HT2 receptors in the DMM on hypoxic ventilatory and airway responses were investigated, while 5-HT release in the DMM was monitored. Adult male mice were anesthetized, and then a microdialysis probe was inserted into the DMM. The mice were placed in a double-chamber plethysmograph. After recovery from anesthesia, the mice were exposed to hypoxic gas (7% O(2) in N(2)) for 5 min with or without a 5-HT2 receptor antagonist (LY-53857) perfused in the DMM. 5-HT release in the DMM was increased by hypoxia regardless of the presence of LY-53857. Immediate onset and the peak of initial hypoxic hyperventilatory responses were delayed. Subsequent ventilatory decline and airway dilation during initial hypoxic hyperventilation were suppressed with LY-53857. These results suggest that 5-HT release increased by hypoxia acts on 5-HT2 receptors in the DMM, which contributes to the immediate onset of initial hypoxic hyperventilation, airway dilation, and subsequent ventilatory decline. Hypoxic ventilatory and airway responses mediated via 5-HT2 receptors in the DMM may play roles in immediate rescue and defensive adaptation for hypoxia and may be included in periodic breathing and the pathogenesis of obstructive sleep apnea.

It is reasonable to hypothesize that dipoles estimated from grand averaged event-related potentials based on summed-up data obtained from multiple subjects and standard head models could correspond to typical brain regions associated to a particular event. Six healthy subjects were enrolled in a study to test this hypothesis. We estimated dipoles from somatosensory-evoked potentials (SEP) elicited by electrical stimulation to the left median nerve. We also created individual three-layered (scalp, skull, and brain) head models from each subject's magnetic resonance imaging scan, and dipoles were estimated from the individual averaged SEP with each individual head model. We then estimated dipoles using grand averaged SEP across all subjects on the standard head model created from the Montreal Neurological Institute (MNI) standard coordinate system brain template to compare the estimated dipoles located on our own head model and those on the MNI. The dipoles in the post-central gyrus were estimated from negative potentials at 20 ms from the grand averaged data incorporated with the MNI head model, corresponding to a typical location related to SEP stimulation. The results suggest the validity of estimating the dipole location from the grand averaged potential of all subjects with the MNI model if we focus on typical regions related to the task.

As a result of intrafusal thixotropy, muscle contraction at a short length followed by passive lengthening enhances the subsequent tonic vibration reflex (TVR). We studied the effects of muscle vibration, contraction, and their combination on the subsequent TVR in the left biceps in 20 healthy men. The preceding vibration (20 or 80 Hz) conditioning at a short or long length was applied to the muscle belly with and without a contraction. After conditioning, distal tendon vibration (80 Hz) was used to elicit the TVR at the test length. The strength of the TVR was measured by surface electromyography. Conditioning with 80-Hz vibration at a short length followed by passive lengthening enhanced the subsequent TVR, which was greater in the presence than in the absence of a conditioning contraction. These results suggest that vibration and contraction work synergistically to develop intrafusal thixotropy.

Respiration is primarily regulated for metabolic and homeostatic purposes in the brainstem. However, breathing can also change in response to changes in emotions, such as sadness, happiness, anxiety or fear. Final respiratory output is influenced by a complex interaction between the brainstem and higher centres, including the limbic system and cortical structures. Respiration is important in maintaining physiological homeostasis and co-exists with emotions. In this review, we focus on the relationship between respiration and emotions by discussing previous animal and human studies, including studies of olfactory function in relation to respiration and the piriform-amygdala in relation to respiration. In particular, we discuss oscillations of piriform-amygdala complex activity and respiratory rhythm.

Thixotropy conditioning of inspiratory muscles at lower lung volumes decreases functional residual capacity (FRC) of following breath cycles with increases in inspiratory capacity. It remains uncertain whether this conditioning would improve exercise tolerance in chronic obstructive pulmonary disease (COPD). Sixteen male stable COPD patients with mild to severe airway obstruction participated. Before the study, all patients completed the 6-min walk test at least twice. The 6-min walk distance (6MWD) was measured after single inspiratory muscle training (IMT) maneuver or without intervention (control) in a randomized cross-over fashion. The 6MWD was also measured after thixotropy conditioning of inspiratory muscles at the maximal expiratory position or without intervention (control). There were no significant differences in the 6MWD after the IMT maneuver (493.2+/-83.7m, P>0.05) versus without intervention (495.7+/-85.9m). The 6MWD after thixotropy conditioning (526.2+/-96.3m, P=0.030) was significantly higher than the 6MWD without intervention (504.3+/-94.1m). The 95% confidence interval of the difference was from 2.6 to 41.2m. Percentage predicted FRC correlated positively with differences in the 6MWD between control and after the thixotropy conditioning maneuver (r=0.78, P=0.007), whereas percentage predicted forced expiratory volume in 1s or the BODE index did not correlate with differences in the 6MWD (P>0.05). Thixotropy conditioning increases self-paced walking distance in patients with COPD. Patients with higher resting FRC benefited more from the conditioning with greater walking distance.

Electroencephalography (EEG) is a non-invasive technique for monitoring electrical activity and has good time resolution. Combining these advantages of EEG with dipole-tracing analysis incorporating a realistic three-layer head model (scalp-skull-brain head model; SSB/DT) allows for the detection of dipoles in the millisecond range and investigation of the processing of cognitive function and movement execution. In this study, we constructed a scalp-skull-brain head model from Montreal Neurological Institute standard brain images and detected dipole localizations in the millisecond range from grand-averaged negative slope (NS) to motor potentials during a simple pinching movement. The left movement activated the presupplementary motor area (pre-SMA), rostral cingulate cortex and rostral premotor area, which are associated with cognitive functions and self-initiated decisions. These areas were associated with the early NS potential during left pinching movement preparation. The right movement activated the caudal cingulate cortex, pre-SMA and caudal premotor area, and these areas were activated just before the execution of movement.

Background and Objective: Thixotropy conditioning of inspiratory muscles changes the end-expiratory position of the respiratory system during resting breathing. We examined the immediate effects of thixotropy conditioning of inspiratory muscles on chest wall inflation induced by CPAP., Methods: A cross-over design study was performed in 13 healthy men. Operating chest wall volume (Vcw) was measured by respiratory inductive plethysmography. Conditioning consisting of a 5 s inspiratory effort at a mask pressure of -20 cm H(2)O was performed under CPAP (10 cm H(2)O) at three Vcw values to change the muscle length at which conditioning occurred: (i) FRC at a CPAP of 10 cm H(2)O (FRC(10)); (ii) FRC at a CPAP of 0 cm H(2)O (FRC(0)); and (iii) RV at a CPAP of 10 cm H(2)O (RV(10))., Results: CPAP (10 cm H(2)O) increased FRC by 0.60-0.70 L. Decreases in operating Vcw were noted after conditioning at RV(10), which decreased end-expiratory Vcw by 0.16 +/- 0.12 L and end-inspiratory Vcw by 0.20 +/- 0.14 L at 180 s (P < 0.01). Inspiratory capacity (1.59 +/- 0.45 L) and inspiratory reserve volume (1.18 +/- 0.40 L) were greater than preconditioning values (1.44 +/- 0.49 L and 0.99 +/- 0.41 L, respectively; P < 0.01). Conditioning at FRC(0) also decreased operating Vcw significantly, but conditioning at FRC(10) did not change operating Vcw., Conclusions: Thixotropy conditioning of inspiratory muscles performed below inflated FRC decreased the level of CPAP-induced inflation.

There are many reports of olfactory impairment in patients with Parkinson's disease (PD) and the impairment can be observed before the appearance of typical PD symptom. Accordingly, olfactory screening tests may predict disease onset and indicates a need for early treatment before classic signs of the disease. Olfaction is dependent on inspiration, and activation of olfactory limbic areas are synchronized with the natural breathing cycle in animals and humans. Subconscious changes in respiratory pattern occur in response to odor stimulation. The use of olfactory stimuli to investigate respiratory pattern could be used to assess olfactory perception and serve as an index for olfactory limbic activation. In this study, we tested olfactory acuity in normal subjects and in patients with PD and recorded V(O2) and respiratory variables during pleasant and unpleasant odor presentation. All subjects were able to detect the odorants; however patients with PD were assigned to one of two groups, group that could recognize odors or the group with impaired odor recognition. Respiratory response toward unpleasant and pleasant odor recognition were weak in PD groups who could recognize odors than normal subject as well as emotional response to odor stimuli. PD group with impaired odor recognition showed no respiratory response toward odor stimuli. PD may experience difficulty in feeling positive emotions toward pleasant odors prior to the unpleasant odor because respiratory responses to pleasant odors may also be related to higher processes including intentional control of breathing pattern as a result of olfactory cortex processing and perceptions or emotions.