Lateralized rhythms of the central and autonomic nervous systems

Traditional Nostril Yoga Breathing Practices and Oxygen Consumption: A Randomized, Cross-over Study

Background

Traditional yoga texts describe "cross nostril breathing," with inhalation and exhalation through different nostrils. Previous research reported no clear differences in oxygen consumption during uninostril breathing (i.e., inhalation and exhalation through the same nostril), hence not supporting right and left uninostril breathing as activating or relaxing, respectively, with no research on oxygen consumed in "cross nostril breathing."

Methods

Oxygen consumed during "cross nostril breathing" was measured in healthy participants (n = 47, males, 26.3 ± 6.4 years). Five sessions (viz., right nostril inspiration yoga breathing [RNIYB], left nostril inspiration yoga breathing [LNIYB], alternate nostril yoga breathing [ANYB], breath awareness (BAW), and quiet rest (QR) were conducted on separate days in random order. Sessions were 33 min in duration with pre, during, and post states.

Results

Volume of oxygen consumed (VO2) and carbon dioxide eliminated (VCO2) increased during RNIYB (9.60% in VO2 and 23.52% in VCO2), LNIYB (9.42% in VO2 and 21.20% in VCO2) and ANYB (10.25% in VO2 and 22.72% in VCO2) with no significant change in BAW and QR. Diastolic blood pressure decreased during BAW and QR and after all five sessions (P < 0.05; in all cases). All comparisons were with the respective preceding state.

Conclusion

During the three yoga breathing practices, the volume of oxygen consumed increased irrespective of the nostril breathed through, possibly associated with (i) conscious regulation of the breath; (ii) attention directed to the breath, and (iii) "respiration-locked cortical activation." Restriction of the study to males reduces the generalizability of the findings.

Case report: binaural beats music assessment experiment

We recruited subjects with the focus on people who were stressed and needed a break to experience relaxation. The study used inaudible binaural beats (BB) to measure the ability of BB to induce a relaxed state. We found through measuring brain wave activity that in fact BB seem to objectively induce a state of relaxation. We were able to see this across several scores, F3/F4 Alpha Assessment and CZ Theta Beta, calculated from EEG readings, that indicated an increase in positive outlook and a relaxing brain, respectively, and scalp topography maps. Most subjects also showed an improvement in Menlascan measurements of microcirculation or cardiovascular score, although the Menlascan scores and Big Five character assessment results were less conclusive. BB seem to have profound effects on the physiology of subjects and since the beats were not audible, these effects could not be attributed to the placebo effect. These results are encouraging in terms of developing musical products incorporating BB to affect human neural rhythms and corollary states of consciousness and warrant further research with more subjects and different frequencies of BB and different music tracks.

Recent insights into respiratory modulation of brain activity offer new perspectives on cognition and emotion

Over the past six years, a rapidly growing number of studies have shown that respiration exerts a significant influence on sensory, affective, and cognitive processes. At the same time, an increasing amount of experimental evidence indicates that this influence occurs via modulation of neural oscillations and their synchronization between brain areas. In this article, we review the relevant findings and discuss whether they might inform our understanding of a variety of disorders that have been associated with abnormal patterns of respiration. We review literature on the role of respiration in chronic obstructive pulmonary disease (COPD), anxiety (panic attacks), and autism spectrum disorder (ASD), and we conclude that the new insights into respiratory modulation of neuronal activity may help understand the relationship between respiratory abnormalities and cognitive and affective deficits.

EEG signatures change during unilateral Yogi nasal breathing

Airflow through the left-and-right nostrils is said to be entrained by an endogenous nasal cycle paced by both poles of the hypothalamus. Yogic practices suggest, and scientific evidence demonstrates, that right-nostril breathing is involved with relatively higher sympathetic activity (arousal states), while left-nostril breathing is associated with a relatively more parasympathetic activity (stress alleviating state). The objective of this study was to further explore this laterality by controlling nasal airflow and observing patterns of cortical activity through encephalographic (EEG) recordings. Thirty subjects participated in this crossover study. The experimental session consisted of a resting phase (baseline), then a period of unilateral nostril breathing (UNB) using the dominant nasal airway, followed by UNB using the non-dominant nasal airway. A 64-channel EEG was recorded throughout the whole session. The effects of nostril-dominance, and nostril-lateralization were assessed using the power spectral density of the neural activity. The differences in power-spectra and source localization were calculated between EEG recorded during UNB and baseline for delta, theta, alpha, beta and gamma bands. Cluster-based permutation tests showed that compared to baseline, EEG spectral power was significantly (1) decreased in all frequency bands for non-dominant nostril UNB, (2) decreased in alpha, beta and gamma bands for dominant nostril UNB, (3) decreased in all bands for left nostril UNB, and (4) decreased in all bands except delta for right nostril UNB. The beta band showed the most widely distributed changes across the scalp. our source localisation results show that breathing with the dominant nostril breathing increases EEG power in the left inferior frontal (alpha band) and left parietal lobule (beta band), whereas non-dominant nostril breathing is related to more diffuse and bilateral effects in posterior areas of the brain.These preliminary findings may stimulate further research in the area, with potential applications to tailored treatment of brain disorders associated with disruption of sympathetic and parasympathetic activity.

Prolonged functional cerebral asymmetry as a consequence of dysfunctional parvocellular paraventricular hypothalamic nucleus signaling: An integrative model for the pathophysiology of bipolar disorder

Approximately 45 million people worldwide are diagnosed with bipolar disorder (BD). While there are many known risk factors and models of the pathologic processes influencing BD, the exact neurologic underpinnings of BD are unknown. We attempt to integrate the existing literature and create a unifying hypothesis regarding the pathophysiology of BD with the hope that a concrete model may potentially facilitate more specific diagnosis, prevention, and treatment of BD in the future. We hypothesize that dysfunctional signaling from the parvocellular neurons of the paraventricular hypothalamic nucleus (PVN) results in the clinical presentation of BD. Functional damage to this nucleus and its signaling pathways may be mediated by myriad factors (e.g. immune dysregulation and auto-immune processes, polygenetic variation, dysfunctional interhemispheric connections, and impaired or overactivated hypothalamic axes) which could help explain the wide variety of clinical presentations along the BD spectrum. The neurons of the PVN regulate ultradian rhythms, which are observed in cyclic variations in healthy individuals, and mediate changes in functional hemispheric lateralization. Theoretically, dysfunctional PVN signaling results in prolonged functional hemispheric dominance. In this model, prolonged right hemispheric dominance leads to depressive symptoms, whereas left hemispheric dominance correlated to the clinical picture of mania. Subsequently, physiologic processes that increase signaling through the PVN (hypothalamic-pituitaryadrenal axis, hypothalamic- pituitary-gonadal axis, and hypothalamic-pituitary-thyroid axis activity, suprachiasmatic nucleus pathways) as well as, neuro-endocrine induced excito-toxicity, auto-immune and inflammatory flairs may induce mood episodes in susceptible individuals. Potentially, ultradian rhythms slowing with age, in combination with changes in hypothalamic axes and maturation of neural circuitry, accounts for BD clinically presenting more frequently in young adulthood than later in life.

Psychophysiological responses to various slow, deep breathing techniques

Deep breathing exercises are commonly used for several health conditions including pain and hypertension. Various techniques are available to practice deep breathing, whereas possible differential psychophysiological effects have not been investigated. We compared four deep breathing techniques and examined outcomes in blood pressure variability, respiratory sinus arrhythmia, baroreflex function, and emotional state. Healthy adult volunteers performed pursed-lips breathing, left and right unilateral nostril breathing, and deep breathing with an inspiratory threshold load (loaded breathing), all at a frequency of 0.1 Hz (i.e., controlled breathing) and for three minutes each. Results showed that blood pressure variability was higher during loaded breathing versus other conditions and higher during pursed-lips breathing versus left and right unilateral nostril breathing. Respiratory sinus arrhythmia was higher during loaded breathing versus other conditions and higher during pursed-lips breathing versus left unilateral nostril breathing. The effect of breathing condition on respiratory sinus arrhythmia was mediated by alterations in blood pressure variability. There was no difference between the breathing conditions in baroreflex sensitivity or effectiveness. Participants rated pursed-lips breathing as more calming and pleasant and with more sense of control (vs. other conditions). Overall, among the four tested deep breathing techniques, loaded breathing was associated with enhanced cardiovascular effects and pursed-lips breathing with better emotional responses, while also enhancing cardiovascular effects (albeit less than loaded breathing). These findings can be informative in applying deep breathing techniques as self-management interventions for health conditions, in which baroreceptors stimulation and autonomic and emotional modulations can be beneficial, such as pain and hypertension.

Using Deep Brain Stimulation to Unravel the Mysteries of Cardiorespiratory Control

This article charts the history of deep brain stimulation (DBS) as applied to alleviate a number of neurological disorders, while in parallel mapping the electrophysiological circuits involved in generating and integrating neural signals driving the cardiorespiratory system during exercise. With the advent of improved neuroimaging techniques, neurosurgeons can place small electrodes into deep brain structures with a high degree accuracy to treat a number of neurological disorders, such as movement impairment associated with Parkinson's disease and neuropathic pain. As well as stimulating discrete nuclei and monitoring autonomic outflow, local field potentials can also assess how the neurocircuitry responds to exercise. This technique has provided an opportunity to validate in humans putative circuits previously identified in animal models. The central autonomic network consists of multiple sites from the spinal cord to the cortex involved in autonomic control. Important areas exist at multiple evolutionary levels, which include the anterior cingulate cortex (telencephalon), hypothalamus (diencephalon), periaqueductal grey (midbrain), parabrachial nucleus and nucleus of the tractus solitaries (brainstem), and the intermediolateral column of the spinal cord. These areas receive afferent input from all over the body and provide a site for integration, resulting in a coordinated efferent autonomic (sympathetic and parasympathetic) response. In particular, emerging evidence from DBS studies have identified the basal ganglia as a major sub-cortical cognitive integrator of both higher center and peripheral afferent feedback. These circuits in the basal ganglia appear to be central in coupling movement to the cardiorespiratory motor program. © 2020 American Physiological Society. Compr Physiol 10:1085-1104, 2020.

Evaluation on Context Recognition Using Temperature Sensors in the Nostrils

We can benefit from various services with context recognition using wearable sensors. In this study, we focus on the contexts acquired from sensor data in the nostrils. Nostrils can provide various contexts on breathing, nasal congestion, and higher level contexts including psychological and health states. In this paper, we propose a context recognition method using the information in the nostril. We develop a system to acquire the temperature in the nostrils using small temperature sensors connected to glasses. As a result of the evaluations, the proposed system can detect breathing correctly, workload at an accuracy of 96.4%, six behaviors at an accuracy of 54%, and eight behaviors in daily life at an accuracy of 86%. Moreover, the proposed system can detect nasal congestion, therefore, it can log nasal cycles that are considered to have a relationship with the autonomic nerves and/or biological states.

Sleep architecture, insulin resistance and the nasal cycle: Implications for positive airway pressure therapy

Background: The global pandemic of metabolic disease is worsening. The metabolic theory of obesity proposes that hormonal changes, especially hyperinsulinaemia, precede metabolic disease development. Although quality sleep is recognised as a key factor for good health, less is known about disrupted sleep as a risk factor for hyperinsulinaemia. Aim: To explore the relationship between sleep, especially sleep architecture and the nasal cycle, on insulin secretion in obstructive sleep apnoea (OSA) with comorbid metabolic disease. This review includes a discussion of the potential role of Rest-Activity-Cycler positive airway pressure (RACer-PAP), a novel non-pharmacological OSA treatment strategy. Methods: A narrative review of all the relevant papers known to the authors was conducted. This review also included results from a polysomnographic sleep clinic pilot study (n = 3) comparing sleep efficiency of RACer-PAP to nasal continuous positive airways pressure (n-CPAP) in OSA patients.  Results: Metabolic disease is strongly associated with disturbed sleep. Sleep architecture influences cerebral hormonal secretion, lateral shifts in the autonomic nervous system and nasal airflow dominance. Disturbed sleep shortens short-wave sleep periods, decreasing insulin sensitivity and glucose tolerance. Improvements to metabolic function during n-CPAP treatment are inconsistent. If RACer-PAP demonstrates superior effects on sleep architecture and autonomic function, it may offer advantages in OSA patients with comorbid metabolic disease. Conclusion: Improving sleep architecture by maintaining the nasal cycle proposes a novel non-pharmacological treatment paradigm for treating OSA with comorbid metabolic disease. Research is required to demonstrate if RACer-PAP therapy influences whole night sleep architecture, sympathovagal balance and markers of metabolic disease.

Alternate-Nostril Yoga Breathing Reduced Blood Pressure While Increasing Performance in a Vigilance Test

BACKGROUND Reports suggest that vigilance or sustained attention increases sympathetic activity. A persistent increase in sympathetic activity can lead to an increase in blood pressure. Alternate-nostril yoga breathing has been shown to be useful to (i) improve attention and (ii) decrease the systolic and diastolic blood pressure. Earlier studies did not report simultaneous recordings of the blood pressure and performance in vigilance tests after alternate-nostril yoga breathing. With this background, the present study was planned to determine if 15 minutes of alternate nostril yoga breathing could improve the performance in a vigilance test without an increase in blood pressure. MATERIAL AND METHODS Fifteen healthy male volunteers participated in the study (group mean age ±SD, 22.4±2.4 years). Participants were assessed on 3 separate days in 3 different sessions. These were (i) alternate nostril yoga breathing, (ii) breath awareness, and (iii) sitting quietly as a control. Blood pressure and the digit vigilance test were simultaneously assessed before and after each session. RESULTS Systolic blood pressure (p<0.01), mean arterial blood pressure (p<0.05), and the time taken to complete the digit vigilance test (p<0.05) significantly decreased following alternate-nostril yoga breathing. The time taken to complete the digit vigilance test differed significantly between sessions (p<0.05). The time taken to complete the digit vigilance test was also significantly decreased after sitting quietly (p<0.01). CONCLUSIONS Alternate-nostril yoga breathing appears to improve performance in the digit vigilance test, along with a reduction in systolic blood pressure. This is suggestive of better vigilance without sympathetic activation.

Measuring and Characterizing the Human Nasal Cycle

Nasal airflow is greater in one nostril than in the other because of transient asymmetric nasal passage obstruction by erectile tissue. The extent of obstruction alternates across nostrils with periodicity referred to as the nasal cycle. The nasal cycle is related to autonomic arousal and is indicative of asymmetry in brain function. Moreover, alterations in nasal cycle periodicity have been linked to various diseases. There is therefore need for a tool allowing continuous accurate measurement and recording of airflow in each nostril separately. Here we provide detailed instructions for constructing such a tool at minimal cost and effort. We demonstrate application of the tool in 33 right-handed healthy subjects, and derive several statistical measures for nasal cycle characterization. Using these measures applied to 24-hour recordings we observed that: 1: subjects spent slightly longer in left over right nostril dominance (left = 2.63 ± 0.89 hours, right = 2.17 ± 0.89 hours, t(32) = 2.07, p < 0.05), 2: cycle duration was shorter in wake than in sleep (wake = 2.02 ± 1.7 hours, sleep = 4.5 ± 1.7 hours, (t(30) = 5.73, p < 0.0001). 3: slower breathing was associated with a more powerful cycle (the extent of difference across nostrils) (r = 0.4, p < 0.0001), and 4: the cycle was influenced by body posture such that lying on one side was associated with greater flow in the contralateral nostril (p < 0.002). Finally, we provide evidence for an airflow cycle in each nostril alone. These results provide characterization of an easily obtained measure that may have diagnostic implications for neurological disease and cognitive state.

Nasal airflow and brain activity: is there a link?

BACKGROUND

Over the past few decades, evidence has emerged suggesting that nasal airflow asymmetry and brain asymmetry are linked. The nose exhibits asymmetrical airflow, with the dominant airflow alternating from one nasal passage to the other over a period of hours. Some authors have suggested a correlation between cerebral hemisphere dominance and nostril dominance. Others have proposed an association between rhythmic fluctuations in nasal airflow and corresponding fluctuations in cerebral hemisphere activity. Based on ancient yoga breathing techniques, newer evidence suggests that altering nasal airflow can influence brain activity, with reports of improved cognitive function caused by unilateral forced nostril breathing. It seems that a nasal airflow stimulus may have an activating effect on the brain, as it has also been shown to trigger seizure activity in epileptic patients.

OBJECTIVES

This article explores these theories in detail, reviews the evidence, and presents new models linking nasal airflow and brain activity.

The subtle body: an interoceptive map of central nervous system function and meditative mind-brain-body integration

Meditation research has begun to clarify the brain effects and mechanisms of contemplative practices while generating a range of typologies and explanatory models to guide further study. This comparative review explores a neglected area relevant to current research: the validity of a traditional central nervous system (CNS) model that coevolved with the practices most studied today and that provides the first comprehensive neural-based typology and mechanistic framework of contemplative practices. The subtle body model, popularly known as the chakra system from Indian yoga, was and is used as a map of CNS function in traditional Indian and Tibetan medicine, neuropsychiatry, and neuropsychology. The study presented here, based on the Nalanda tradition, shows that the subtle body model can be cross-referenced with modern CNS maps and challenges modern brain maps with its embodied network model of CNS function. It also challenges meditation research by: (1) presenting a more rigorous, neural-based typology of contemplative practices; (2) offering a more refined and complete network model of the mechanisms of contemplative practices; and (3) serving as an embodied, interoceptive neurofeedback aid that is more user friendly and complete than current teaching aids for clinical and practical applications of contemplative practice.

Nasal cycle dominance and hallucinations in an adult schizophrenic female

Nasal dominance, at the onset of hallucinations, was studied as a marker of both the lateralized ultradian rhythm of the autonomic nervous system and the tightly coupled ultradian rhythm of alternating cerebral hemispheric dominance in a single case study of a schizophrenic female. Over 1086 days, 145 hallucination episodes occurred with left nostril dominance significantly greater than the right nostril dominant phase of the nasal cycle. A right nostril breathing exercise, that primarily stimulates the left hemisphere, reduces symptoms more quickly for hallucinations.

Exploring the benefits of unilateral nostril breathing practice post-stroke: attention, language, spatial abilities, depression, and anxiety

OBJECTIVE

Unilateral nostril breathing (UNB) is a yogic pranayama technique that has been shown to improve verbal and spatial cognition in neurologically intact individuals. Early study of UNB in healthy individuals has shown benefits for attention and memory. This preliminary study explored whether UNB influenced various measures of attention, language, spatial abilities, depression, and anxiety in post-stroke individuals, both with and without aphasia.

DESIGN

A within-subjects repeated-measures design was used to determine whether UNB improved cognitive, linguistic, and affect variables in post-stroke individuals. Within-subjects comparisons determined UNB's effects over time, and between-subjects comparison was used to determine whether changes in these variables differed between post-stroke individuals with and without aphasia.

SETTING

Athens and Atlanta, Georgia.

PARTICIPANTS

Eleven post-stroke individuals participated in a 10-week UNB program. Five individuals had stroke-induced left hemisphere damage with no diagnosis of aphasia (left hemisphere damage control group; LHD), and six individuals experienced left hemisphere damage with a diagnosis of aphasia (individuals with aphasia group; IWA).

MEASURES

Individuals were assessed on measures of attention, language, spatial abilities, depression, and anxiety before, during, and after UNB treatment.

RESULTS

UNB significantly decreased levels of anxiety for individuals in both groups. Performance on language measures increased for the individuals with aphasia.

CONCLUSIONS

Significant findings for language and affect measures indicate that further investigation regarding duration of UNB treatment and use of UNB treatment alongside traditional speech-language therapy in post-stroke individuals is warranted.

Yoga breathing through a particular nostril is associated with contralateral event-related potential changes

BACKGROUND

In earlier studies uninostril yoga breathing was shown to influence the activity of the cerebral hemispheres differently, based on (i) auditory evoked potentials recorded from bilateral scalp sites, and (ii) performance in hemisphere-specific tasks. But change in P300 (event-related potential generated when subjects attend to and discriminate between stimuli) from bilateral scalp sites when subjects were practicing uni- and alternate-nostril breathing are yet to be explored.

AIM

The present study was designed to determine whether or not immediately after uninostril or alternate nostril yoga breathing there would be a change in the ability to pay attention to a given stimulus.

MATERIALS AND METHODS

Twenty-nine healthy male volunteers, with ages between 20 and 45 years were randomly allocated to five sessions, viz., (i) right-, (ii) left-, (iii) alternate-nostril yoga breathing, (iv) breath awareness and (v) no intervention, each for 45 min on separate days. The P300 event related potential was recorded using an auditory oddball paradigm from sites on the left (C3) and right (C4), referenced to linked earlobes, before and after each session.

RESULTS

Post-hoc analysis with Bonferroni adjustment showed that the P300 peak latency was significantly lower at C3 compared to that at C4, following right nostril yoga breathing (P<0.05).

CONCLUSION

These results suggest that right nostril yoga breathing facilitates the activity of contralateral (left) hemisphere, in the performance of the P300 task.

Nostril dominance at rest associated with performance of a left hemisphere-specific cancellation task

BACKGROUND

An association has been reported between the dominant nostril through which we breathe and the cerebral hemisphere found to be active.

AIMS

To understand the association between the nostril dominant at rest and the performance in a cancellation task using verbal information-a left hemisphere task.

MATERIALS AND METHODS

Two hundred eighty-nine normal, healthy volunteers attending a one week nonresidential yoga camp were assessed in a single 30 minute period. Nostril dominance was assessed using a standard method. After this, participants were given the letter cancellation task and nostril dominance was again checked. For each participant, the numbers of letters that had been left out and wrongly cancelled as well as total errors were assessed. The Mann-Whitney u test and Chi-Square test were used to assess whether there was a significant difference in cancellation task performance between right and left nostril-dominant persons.

RESULTS

There was no statistically significant difference between right and left nostril-dominant participants.

CONCLUSIONS

The present results do not support previous findings of contralateral cerebral hemisphere improvement with breathing through a specific nostril.

Bright light effects on ultradian rhythms in performance on hemisphere-specific tasks

Ultradian rhythms in indices of brain hemisphere activity and in cognitive performance have been found in numerous studies. Asymmetry of these rhythms with regard to phase and frequency have also been documented in some studies. There is some evidence that bright light can affect ultradian rhythms of arousal state and vigilance. A study on unilateral exposure to bright light has demonstrated more pronounced effects of bright light on the right hemisphere. The aim of this study was to examine whether daytime intermittent bright light could affect parameters of ultradian rhythms in performance speed on hemisphere-specific tasks, and whether the effect of bright light was symmetric for the rhythms in performance on hemisphere-specific tasks presented laterally. A counter-balanced, within-subject research design was applied. The performance of 15 participants on hemisphere-specific tasks exposed laterally was measured every 30 min starting at 08:00 h and ending at 20:30 h in intermittent bright light (IBL, pulses of 15 min of 4000 lux light regularly interspersed between 45 min of background light levels of 300 lux) and in ordinary room light (ORL) conditions (300 lux). Individual time series data were subjected to cosinor analysis. General linear model analyses (the factors were: level of processing, visual field, and the task) were performed on the rhythms' parameters. There was a substantial lengthening of the rhythms' periods in IBL conditions for performance speed on spatial tasks and an increase in amplitude of the rhythms of performance speed for spatial tasks in both visual fields and for verbal tasks in the left visual field in the IBL conditions when compared to the ORL conditions. The results showed that the schedule of light exposure affected ultradian rhythms of hemisphere-specific tasks differently and that the right hemisphere seems to be more "sensitive" to light than the left hemisphere.

Relationships between intestinal parasitosis and handedness

The aim of the study was to investigate if there is a possible relation between intestinal parasitosis and handedness in patients with suspected intestinal parasitosis. Hand preference was assessed on the Edinburgh Handedness Inventory. Stool samples were examined microscopically for the presence of parasite. In the present study right-handers had many more helminth infections and left-handers had many more protozoon infections. Lower rate of helminth infections in the present study, and higher asthma incidences in the left-handed population in literature, may be associated with different immune machinery in left-handed people than in right-handed ones.

Immediate effect of specific nostril manipulating yoga breathing practices on autonomic and respiratory variables

The effect of right, left, and alternate nostril yoga breathing (i.e., RNYB, LNYB, and ANYB, respectively) were compared with breath awareness (BAW) and normal breathing (CTL). Autonomic and respiratory variables were studied in 21 male volunteers with ages between 18 and 45 years and experience in the yoga breathing practices between 3 and 48 months. Subjects were assessed in five experimental sessions on five separate days. The sessions were in fixed possible sequences and subjects were assigned to a sequence randomly. Each session was for 40 min; 30 min for the breathing practice, preceded and followed by 5 min of quiet sitting. Assessments included heart rate variability, skin conductance, finger plethysmogram amplitude, breath rate, and blood pressure. Following RNYB there was a significant increase in systolic, diastolic and mean pressure. In contrast, the systolic and diastolic pressure decreased after ANYB and the systolic and mean pressure were lower after LNYB. Hence, unilateral nostril yoga breathing practices appear to influence the blood pressure in different ways. These effects suggest possible therapeutic applications.

Selective unilateral autonomic activation: implications for psychiatry

Research advances have led to three methods for selectively activating one half of the autonomic nervous system in humans. The first method is an ancient yogic technique called unilateral forced nostril breathing (UFNB) that employs forced breathing through only one nostril while closing off the other. The second method works by stimulation of an autonomic reflex point on the fifth intercostal space near the axilla. The most recent method employs unilateral vagus nerve stimulation (VNS) via the mid-inferior cervical branch and requires surgical implantation of a wire and pacemaker. UFNB is non-invasive and seems to selectively activate the ipsilateral branch of the sympathetic nervous system with a possible compensation effect leading to contralateral VNS. UFNB and VNS have been employed to treat psychiatric disorders. While UFNB has been studied for its potential effects on the endogenous ultradian rhythms of the autonomic and central nervous system, and their tightly coupled correlates, VNS has yet to be studied in this regard. This article reviews these three methods and discusses their similarities, putative mechanisms, their studied effects on the endogenous autonomic nervous system and central nervous system rhythms, and their implications for the treatment of psychiatric disorders.

Immersion of the hand in ice water releases adrenergic vasoconstrictor tone in the ipsilateral temple

Immersion of the hand in painfully cold water induces cutaneous vasodilatation in the temples, more so ipsilaterally than contralaterally. To investigate the mechanism of this response, guanethidine or saline was administered by transcutaneous iontophoresis to a recording site in the temple of ten participants before they immersed one of their hands in ice water. Guanethidine displaces noradrenaline from sympathetic nerve terminals and inhibits sympathetic noradrenergic neurotransmission. Therefore, it was hypothesized that guanethidine pre-treatment would block vasodilatation mediated by release of sympathetic vasoconstrictor tone in cutaneous vessels in the temple. During hand immersion, increases in the amplitude of the pulse waveform detected by laser Doppler flowmetry were greater in the ipsilateral than contralateral temple (86% vs. 34% above baseline, p<0.05), and pre-treatment with guanethidine prevented this asymmetric response (ipsilateral response 21% above baseline and contralateral response 32%, difference not significant). Guanethidine also inhibited ipsilateral increases in cutaneous blood flow during hand immersion in responsive participants. These findings suggest that limb pain inhibited ipsilateral adrenergic vasoconstrictor outflow in the temple. Thus, the findings challenge the concept of the sympathetic nervous system as a "mass action" system that discharges in unison to meet environmental demands. Instead, they suggest that the sympathetic nervous system is highly differentiated, with separate control of discrete reflex pathways on each side of the body.

Diurnal autonomic variations and emotional reactivity

Diurnal temporal variations of emotional reactivity were investigated in relationship with fluctuations of psychophysiological state, evaluated by tonic autonomic activity. Neutral and unpleasant pictures, selected to constitute seven matched sets, were evaluated by 12 participants during seven sessions in the course of daytime. Skin conductance level (SCL) was recorded at the beginning of each session, whereas skin conductance responses (SCRs), affective evaluation and emotional experience were measured during or after each session. Data show significant temporal variations for SCL, SCRs and emotional experience which follow similar patterns during the daytime. Discussion highlights the role of temporal patterns of autonomic activity as an interesting basis to better understand the emotional regulation and affective disorders.

Patient perspectives: Kundalini yoga meditation techniques for psycho-oncology and as potential therapies for cancer

The ancient system of Kundalini Yoga (KY) includes a vast array of meditation techniques. Some were discovered to be specific for treating psychiatric disorders and others are supposedly beneficial for treating cancers. To date, 2 clinical trials have been conducted for treating obsessive-compulsive disorder (OCD). The first was an open uncontrolled trial and the second a single-blinded randomized controlled trial (RCT) comparing a KY protocol against the Relaxation Response and Mindfulness Meditation (RRMM) techniques combined. Both trials showed efficacy on all psychological scales using the KY protocol; however, the RCT showed no efficacy on any scale with the RRMM control group. The KY protocol employed an OCD-specific meditation technique combined with other techniques that are individually specific for anxiety, low energy, fear, anger, meeting mental challenges, and turning negative thoughts into positive thoughts. In addition to OCD symptoms, other symptoms, including anxiety and depression, were also significantly reduced. Elements of the KY protocol other than the OCD-specific technique also may have applications for psycho-oncology patients and are described here. Two depression-specific KY techniques are described that also help combat mental fatigue and low energy. A 7-part protocol is described that would be used in KY practice to affect the full spectrum of emotions and distress that complicate a cancer diagnosis. In addition, there are KY techniques that practitioners have used in treating cancer. These techniques have not yet been subjected to formal clinical trials but are described here as potential adjunctive therapies. A case history demonstrating rapid onset of acute relief of intense fear in a terminal breast cancer patient using a KY technique specific for fear is presented. A second case history is reported for a surviving male diagnosed in 1988 with terminal prostate cancer who has used KY therapy long term as part of a self-directed integrative care approach.

Effect of unilateral forced nostril breathing on tonic accommodation and intraocular pressure

BACKGROUND

Unilateral forced nostril breathing (UFNB) has specific measurable effects on the autonomic nervous system. Ocular accommodation, which is controlled by the autonomic nervous system, would be expected to be under the influence of UFNB when it is applied. The purpose of this study was to investigate the effect of UFNB on the resting state of the accommodation system, i. e. tonic accommodation (TA), along with measures of intraocular pressure (IOP), blood pressure and heart rate.

METHODS

TA levels were measured using the Shin-Nippon autorefractor before and after 20 minutes of UFNB. IOP, blood pressure and heart rate, which are known to be affected by UFNB, were also measured with a non-contact tonometer and an automated blood pressure monitor respectively.

RESULTS

Right and left UFNB produced slight, but not significant changes in TA. However, there was a tendency for left UFNB to produce a greater decrease in TA in subjects with higher base-line TA levels. Right UFNB produced a statistically significant decrease in IOP while the effect of left UFNB on IOP was not significant.

CONCLUSION

UFNB produced changes in IOP consistent with previous reports. As studied in this trial, UFNB did not have any significant effect on TA. Further studies using a larger sample size are required to investigate the effect of UFNB on the autonomic inputs to the ciliary muscle of the eye and the subsequent measures of tonic accommodation.

The effects of yoga on the attention and behavior of boys with Attention-Deficit/ hyperactivity Disorder (ADHD)

Boys diagnosed with ADHD by specialist pediatricians and stabilized on medication were randomly assigned to a 20-session yoga group (n = 11) or a control group (cooperative activities; n = 8). Boys were assessed pre- and post-intervention on the Conners' Parent and Teacher Rating Scales-Revised: Long (CPRS-R:L & CTRS-R:L; Conners, 1997), the Test of Variables of Attention (TOVA; Greenberg, Cormna, & Kindschi, 1997), and the Motion Logger Actigraph. Data were analyzed using one-way repeated measures analysis of variance (ANOVA). Significant improvements from pre-test to post-test were found for the yoga, but not for the control group on five subscales of the Conners' Parents Rating Scales (CPRS): Oppositional, Global Index Emotional Lability, Global Index Total, Global Index Restless/Impulsive and ADHD Index. Significant improvements from pre-test to post-test were found for the control group, but not the yoga group on three CPRS subscales: Hyperactivity, Anxious/Shy, and Social Problems. Both groups improved significantly on CPRS Perfectionism, DSM-IV Hyperactive/ Impulsive, and DSM-IV Total. For the yoga group, positive change from pre- to post-test on the Conners' Teacher Rating Scales (CTRS) was associated with the number of sessions attended on the DSM-IV Hyperactive-Impulsive subscale and with a trend on DSM-IV Inattentive subscale. Those in the yoga group who engaged in more home practice showed a significant improvement on TOVA Response Time Variability with a trend on the ADHD score, and greater improvements on the CTRS Global Emotional Lability subscale. Results from the Motion Logger Actigraph were inconclusive. Although these data do not provide strong support for the use of yoga for ADHD, partly because the study was under-powered, they do suggest that yoga may have merit as a complementary treatment for boys with ADHD already stabilized on medication, particularly for its evening effect when medication effects are absent. Yoga remains an investigational treatment, but this study supports further research into its possible uses for this population. These findings need to be replicated on larger groups with a more intensive supervised practice program.

Staring at one side of the face increases blood flow on that side of the face

To investigate the effect of observation on blushing, an experimenter sat next to 28 participants and looked closely at one cheek while the participant sang (embarrassing) or read aloud (not embarrassing). Increases in cheek temperature were greater on the observed than the unobserved side during both tasks. Changes in cheek temperature were symmetrical when the experimenter sat next to another 23 participants and looked straight ahead, as well as when the experimenter stared at one side of the participant's face through a glass window while the participant sang. However, increases in cutaneous blood flow were greater on the observed than the unobserved side of the forehead during singing. These findings suggest that staring at one side of the face triggers an ipsilateral increase in facial blood flow.

Hormonal changes during 17 days of head-down bed-rest

We investigated in six men the impact of 17 days of head-down bed rest (HDBR) on the daily rhythms of the hormones involved in hydroelectrolytic regulation. This HDBR study was designed to mimic a real space flight. Urine samples were collected at each voiding before, during and after HDBR. Urinary excretion of Growth Hormone (GH), Cortisol, 6 Sulfatoxymelatonin, Normetadrenaline (NMN) and Metadrenaline (NM) was determined. A decrease in urinary cortisol excretion during the night of HDBR was noted. For GH, a rhythm was found before and during HDBR. The rhythm of melatonin, evaluated with the urine excretion of 6 Sulfatoxymelatonin (aMT6S), the main hepatic metabolite, persisted throughout the experiment without any modification to the level of phase. A decrease during the night was noted for normetadrenaline urinary derivates, but only during the HDBR.

Brain interleukin asymmetries and paw preference in mice

The two sides of the brain are differently involved in the modulation of immune responses as demonstrated by lesion and behavioral approaches. To study the interactions between cerebral cortex cytokines and brain lateralization, three groups of BALB/c mice were selected on the basis of their performance in the paw preference test (left-pawed, ambidextrous and right-pawed) and the levels of interleukin-1beta and interleukin-6 were measured in the two cerebral cortices after an intraperitoneal saline or lipopolysaccharide. Generally, right cortices had higher interleukin-1beta and interleukin-6 levels than left cortices for both saline and lipopolysaccharide-treated mice. A strong correlation between the levels of interleukin-1beta and interleukin-6 in right and left cortices and behavioral lateralization was observed. For the saline-treated mice: in their left cortices, interleukin-1beta levels were higher for ambidextrous mice than for right-pawed mice (P<0.05); in their right cortices, interleukin-6 levels were higher for ambidextrous mice than for right-/left-pawed mice, and right-pawed mice have higher levels of interleukin-6 than left-pawed mice (P<0.01). In their left cortices, interleukin-6 levels are higher for left-pawed mice than for both ambidextrous and right-pawed mice (P<0.01). In their left cortices, interleukin-6 levels are higher for left-pawed mice than for both ambidextrous and right-pawed mice (P<0.01). The quadratic curve equations showed that the levels of interleukin-1beta and interleukin-6 in the right/left cortices had a highly significant correlation with paw preference scores in both normal and lipopolysaccharide-treated mice. In conclusion, the present report demonstrated that the basal levels of interleukin-1beta and interleukin-6 were higher in the right cortex than left cortex in mice. There was a strong correlation between the levels of interleukin-1beta and interleukin-6 and behavioral lateralization, and cytokine asymmetries had a strong correlation with the direction and the intensity of behavioral lateralization.

Ultradian sleep rhythms of lateral EEG, autonomic, and cardiovascular activity are coupled in humans

This study compared the dynamics of multiple systems during sleep with earlier results during waking rest. Three consecutive nights of data were collected from three healthy adults for 10 variables: left and right central EEGs; the nasal cycle (NC); beat-to-beat measures of CO, SV, HR, SBP, DBP, MAP, and hemoglobin-oxygen saturation. Time series analysis detected periods at 280-300, 215-275, 165-210, 145-160, 105-140, 70-100, and 40-65 min bins with the greatest spectral power in longer periods. We found significance across subjects with all parameters at 280-300, 105-140 (except left EEG power, left minus right EEG power, and HR), 70-100, and 40-65 min. Significant periods were reported earlier during waking for the NC, pituitary hormones, catecholamines, insulin, and cardiovascular function in five bins at 220-340, 170-215, 115-145, 70-100, and 40-65 min, with 115-145, 70-100, and 40-65 min common across all variables. These results suggest that lateral EEG power during sleep has a common pacemaker (the hypothalamus), or a mutually entrained pacemaker, with the cardiovascular and autonomic nervous systems (ANS), and that the waking ultradians of the neuroendocrine and fuel regulatory hormones may also be coupled to lateral EEG activity. Taken together these results present a new perspective for the Basic Rest-Activity Cycle and the physiology of the ANS-central nervous system during both waking and sleep.

Lateralized ultradian rhythms: evidence from tactile discrimination of either hand

Endogenous ultradian rhythms with periods of one or a few hours affect not only on physiological and behavioural functions but also perception and cognition. In particular, lateralized ultradian rhythms which seem to operate separately in the right and left hemispheres of the brain can be monitored by testing the tactile discrimination of the contralateral hand. The present paper is based on two subsequent studies: First, ultradian rhythms in tactile discrimination of either hand were examined in German subjects under laboratory conditions. Considerably different ultradian periods of right and left-handed tactile error rate were found in men but not in women. In a second study, a group of Kenyan Masai shepherds were tested while the subjects were leading herds on daily feeding routes through a savanna habitat. They showed ultradian periods of about 2 hours in tactile discrimination of either hand. Since the right hemisphere is specialized for visuospatial, the left for verbal processing lateralized ultradian rhythms may serve for a long-scale timing of neural processes underlying spatial and semantic mapping of the environment. Sex difference in German subjects and lateral differences found in left-handed (right-hemispheric) ultradian rhythms of German and Masai subjects are discussed from this point of view.

Mental walking through a complex maze influences lateralized ultradian rhythms

Subjects of two experimental groups, 10 males and 10 females in each group, explored artificial environments represented by compact city mazes. The mazes, a simple and a complex one, were generated by means of a computer program. After turning the program on, a scene with houses, streets, and alleys appeared on a TV screen. The subjects sat in front of the screen and manoeuvered through the simple or the complex maze with the help of a hand-operated device. Correspondingly the street scenes changed in such a way that the subject had the illusion of a normal pace. Each subject explored one maze for eight hours. Every 15 min. an experimenter interrupted the subject's walk and measured tactile discrimination in either hand. Ultradian periodic variations in the tactile error rate of the right and left hands with periods of 2 or 3 hours are found. They are considered manifestations of endogenous rhythms operating separately in the left and right cerebral hemispheres. As demonstrated in a previous paper, lateralized ultradian rhythms in tactile discrimination are different for males and females when tested under quiet laboratory conditions. The present paper shows that the rhythms are specifically influenced in both sexes by the spatial complexity of an artificial environment (maze). These findings are discussed from an evolutionary point of view.

Ultradian rhythms in young and adult mice: further support for the basic rest-activity cycle

Basic Rest-Activity Cycle (BRAC) rhythmicity has been shown in many parameters in animals as well as in humans. A similarity between the periods of BRAC and REM/NREM cycles has been frequently reported. However, this does not necessarily prove the idea that BRAC is a diurnal extension of the REM/NREM cycle. A concurrent variation of the BRAC and REM/NREM cycles during ontogenetic development would confirm the link between these rhythms. For this purpose, we investigated the existence of a BRAC periodicity in young (23 days of life) and adult (90 days of life) mice, in comparison with the REM/NREM species-specific cycle. Reaction times of the avoidance response to a visual warning stimulus that preceded an electric shock were measured by a computer-controlled shuttle-box. Results revealed the existence of an evident ultradian rhythm in all subjects confirming previous reports of a 20-min BRAC in avoidance behavior of adult mice. Furthermore, young mice showed a shorter periodicity of about 9 min, which is analogous to their 10-min REM/NREM cycle. These results seem to confirm the hypothesis of a strong relationship between BRAC and REM/NREM sleep cycle.

Behavioural lateralisation of the tetrapod type in the zebrafish (Brachydanio rerio)

Visual lateralisation resembling that found in a bird (domestic chick) is here demonstrated in a teleost (zebrafish, Brachydanio rerio). Zebrafish predominantly view objects with the body axis close to facing the object (0-20 degrees on either side of facing). Strange objects were viewed at first exposure chiefly with the right frontal field; so was a complex and unfamiliar scene made up of familiar components. In a second trial, using the same stimulus or scene, left frontal viewing tended to be used instead. A familiar partner (a fish of another species) was viewed left frontally. The domestic chick also uses the left eye to view familiar stimuli, shifting to the right when it has to decide what response is appropriate to the object at which it is looking. An empty scene in which nothing could be concealed (and so no response was called for) was viewed by zebrafish with the left eye from the start. In zebrafish and the chick, the right eye is used when it is necessary to inhibit premature response, in order to sustain viewing until a decision is reached, and the left is used when it is necessary to keep an eye on a familiar or clearly empty scene. The findings suggest homology of cerebral lateralisation in teleost fish and tetrapods.

Yoga breathing through a particular nostril increases spatial memory scores without lateralized effects

Uninostril breathing facilitates the performance on spatial and verbal cognitive tasks, said to be right and left brain functions, respectively. Since hemispheric memory functions are also known to be lateralized, the present study assessed the effects of uninostril breathing on the performance in verbal and spatial memory tests. School children (N = 108 whose ages ranged from 10 to 17 years) were randomly assigned to four groups. Each group practiced a specific yoga breathing technique: (i) right nostril breathing, (ii) left nostril breathing, (iii) alternate nostril breathing, or (iv) breath awareness without manipulation of nostrils. These techniques were practiced for 10 days. Verbal and spatial memory was assessed initially and after 10 days. An age-matched control group of 27 were similarly assessed. All 4 trained groups showed a significant increase in spatial test scores at retest, but the control group showed no change. Average increase in spatial memory scores for the trained groups was 84%. It appears yoga breathing increases spatial rather than verbal scores, without a lateralized effect.

Functional brain asymmetry, handedness and age characteristics of climacterium in women

A total of 1985 women aged between 55 and 65 were distributed into two groups (145 left-handers and 1840 right-handers). They were asked to complete a questionnaire on the appearance of menopause, duration of menopausal transition and age of menopause. In left-handed women a significantly earlier appearance of premenopause was established together with a shorter menopause transition and an earlier occurrence of menopause. These results give grounds for a correlation between handedness, functional brain asymmetry, respectively and the genetically determined fading away of ovary steroidogenesis associated with the appearance and progression of the climacterium. In light of the available literature we assume that progressive reduction in ovarian function during climacterium is coupled with possible specific functioning of the hypothalamo-pituitary-gonadal axis, dependent on the type of hemispheric asymmetry.

Ultradian rhythms in the N1-P2 amplitude of the visual evoked potential in two inbred strains of mice: DBA/2J and C57BL/6

Ultradian rhythmicity has been showed in many behavioural parameters in animals as well as in humans. We investigated the existence of a Basic Rest-Activity Cycle (BRAC) rhythm in amplitude fluctuations of mice's visual evoked potential (VEP) primary component. Two inbred strains of mice, C57BL/6 and DBA/2J, were used to verify the influence of genetics on biological rhythm as well. Results revealed the existence of an evident rhythm in the parameter under study and confirm previous reports of a 20 min. BRAC in avoidance behavior in DBA mice. This rhythm shows similar period within each strain, but significatively different periods between strains. Observed periods are near to species-specific reported BRAC cycle. Genetic hypothesys is suggested to explain differences between strains in expression of ultradian rhythm.

Ultradian rhythms in avoidance behavior of DBA mice

This study investigates ultradian rhythm in avoidance behavior of mice, which may constitute a basic rest activity cycle (BRAC). Reaction times (RTs) of an avoidance response to a visual warning stimulus that preceded an electric shock were measured by the use of a computer-controlled shuttle box. The male naive DBA mice were brought to a criterion of 98% correct responses in numerous training sessions. For each subject, all the temporal sequences of the RTs in the trials following achievement of the criterion were examined with discrete Fourier transform. Periodograms were obtained from three sessions for each of the two animals in the first experiment and from 15 subjects in the second experiment. Analysis of the periodograms reveals a stable rhythm in avoidance behavior of mice, with a period of about 14 min. The presence of these periodicities could show the existence, also in small rodents, of a BRAC rhythm.

The effects of unilateral forced nostril breathing on cognitive performance

This study describes the effects of 30 minutes of unilateral forced nostril breathing on cognitive performance in 51 right-handed undergraduate psychology students (25 males and 26 females). A verbal analogies task modeled after the Miller Analogies and SAT Tests was used as a test of left-hemispheric performance and mental rotation tasks based on the Vandenburg and Kuse adaptation of Shepard and Metzler's tests were used as spatial tasks for testing right-hemispheric performance. Spatial task performance was significantly enhanced during left nostril breathing in both males and females, p = .028. Verbal task performance was greater during right nostril breathing, but not significantly p = .14. These results are discussed in comparison to other cognitive and physiological studies using unilateral forced nostril breathing. This yogic breathing technique may have useful application in treating psychophysiological disorders with hemispheric imbalances and disorders with autonomic abnormalities.

The effects of unilateral forced nostril breathing on the heart

Three experiments are described that employ impedance cardiography to monitor the effects of unilateral forced nostril breathing (UFNB) on the heart. Experiment 1 includes 7 subjects (4 males, 3 females) with a respiratory rate of 6 breaths/min (BPM). Experiment 2 includes 16 trials using one subject to examine the intraindividual variability, at 6 BPM. Experiment 3 includes 10 trials with the same subject in experiment 2, but with a respiratory rate of 2-3 breaths/s. This rapid rate of respiration is a yogic breathing technique called "breath of fire" or "kapalabhatti" and employs a very shallow but rapid breath in which the abdominal region acts like a bellows. All 3 experiments demonstrated that right UFNB increases heart rate (HR) compared to left. Experiment 1 gave 7 negative slopes, or lowering in HR with left nostril breathing and 7 positive slopes, or increases in HR with right nostril breathing, p = .001. The second and third experiments showed differences in HR means in which right UFNB increases HR more than left, p = .013, p = .001, respectively. In experiment 2 stroke volume was higher with left UFNB, p = .045, compensating for lower HR. Left UFNB increased end diastolic volume as measured in both experiments 1 and 2, p = .006, p = .001, respectively. These results demonstrate a unique unilateral effect on sympathetic stimulation of the heart that may have therapeutic value.

The ultradian rhythm of alternating cerebral hemispheric activity

This review covers cognitive and electroencephalographic studies of the ultradian rhythm of alternating cerebral hemispheric activity found in humans and animals. This endogenous alternation of right and left dominance ranges in periodicity from about 25 to 300 min with peaks between 90-200 min during waking and around 100 min during sleep. Studies of lateralized EEG activity during sleep are reported as correlates of the REM-NREM sleep cycle. Studies of lateralized ultradian rhythms of EEG during wakefulness reveal a correlation between hemispheric dominance and the nasal cycle. The rhythm of cerebral dominance has also been identified with tests of lateralized cognitive performance using left and right hemisphere dependent tasks. Awakening from REM or NREM sleep is associated with different effects on left or right hemispheric dominance. This rhythm plays an important role in cognitive performance, memory processes, visual perception, levels of arousal and performance, mood, and individual and social behavior.