Subjective feeling of control during fNIRS-based neurofeedback targeting the DL-PFC is related to neural activation determined with short-channel correction.

Neurofeedback (NF) training is a promising preventive and therapeutic approach for brain and behavioral impairments, the dorsolateral prefrontal cortex (DL-PFC) being a relevant region of interest. Functional near-infrared spectroscopy (NIRS) has recently been applied in NF training. However, this approach is highly sensitive to extra-cerebral vascularization, which could bias measurements of cortical activity. Here, we examined the feasibility of a NF training targeting the DL-PFC and its specificity by assessing the impact of physiological confounds on NF success via short-channel offline correction under different signal filtering conditions. We also explored whether the individual mental strategies affect the NF success. Thirty volunteers participated in a single 15-trial NF session in which they had to increase the oxy-hemoglobin (HbO2) level of their bilateral DL-PFC. We found that 0.01-0.09 Hz band-pass filtering was more suited than the 0.01-0.2 Hz band-pass filter to highlight brain activation restricted to the NF channels in the DL-PFC. Retaining the 10 out of 15 best trials, we found that 18 participants (60%) managed to control their DL-PFC. This number dropped to 13 (43%) with short-channel correction. Half of the participants reported a positive subjective feeling of control, and the "cheering" strategy appeared to be more effective in men (p<0.05). Our results showed successful DL-PFC fNIRS-NF in a single session and highlighted the value of accounting for extra cortical signals, which can profoundly affect the success and specificity of NF training.

Motor Imagery and Frontal Head Oxygenation: An fNIRS Study.

Motor imagery (MI) is a manifestation of mental movements, but it cannot be identified visually. Therefore, to a large extent, MI assessment has not yet been established. The present study aimed to investigate whether frontal oxy-Hb changes and cardiac autonomic nervous system activity during MI are associated with the psychometric scale assessment of MI and clarify the utility of each index in MI assessment. Thirty-one healthy men and women were included in this study, and Pocket NIRS Duo was used to assess frontal oxygenated hemoglobin levels during walking MI. Simultaneously, heart rate and sympathetic index (low and high frequency (LF/HF) during MI were evaluated using Chiryou Meijin, a heart rate frequency analyser. In addition, a psychometric scale evaluation was carried out in MC and VAS, and its correlation with oxy-Hb levels, heart rate (HR), and LF/HF was investigated. HRs and LF/HF during MI were significantly increased compared with those at rest. However, oxy-Hb levels during MI were not increased. There was a significant correlation between right oxy-Hb levels and mental chronometry (MC) during MI (r = -0.3, p < 0.05). HR and LF/HF were not correlated with MC. VAS was not correlated with oxy-Hb levels, HR, or LF/HF. The results of this study confirm an association between MI performance and frontal oxy-Hb changes and that brain activity is not necessarily elevated during MI. HR were significantly increased but did not show any association with MC.

Brain Functional Connectivity in Middle-Aged Hong Chuan Tai Chi Players in Resting State.

Tai Chi is an effective strategy for slowing cognitive decline, although the underlying mechanism remains unclear. We designed a cross-sectional study to examine brain functional connectivity in middle-aged Hong Chuan Tai Chi practitioners. Eighteen middle-aged Hong Chuan Tai Chi practitioners and 22 age-matched Tai Chi-naïve controls completed functional near-infrared spectroscopy (fNIRS) tests to evaluate oxyhemoglobin changes in the prefrontal cortex (PFC), motor cortex (MC), and occipital cortex (OC) in five frequency intervals (I, 0.6-2 Hz; II, 0.145-0.6 Hz; III, 0.052-0.145 Hz; IV, 0.021-0.052 Hz; V, 0.0095-0.021 Hz). Wavelet phase coherence was used to analyze the match between the instantaneous phases of the two signals to accurately measure brain functional connectivity. Global cognition was measured using the Montreal Cognitive Assessment scale. Compared with the control group, Hong Chuan Tai Chi practitioners had better global cognition (p < 0.01) and showed higher functional connectivity of the PFC, MC, and OC in intervals I, III, VI, and V in the resting state within the same brain hemispheres or between the left and right hemispheres. Our findings revealed that middle-aged Hong Chuan Tai Chi practitioners had higher functional connectivity of the PFC, MC, and OC across both brain hemispheres in cardiac activity, myogenic activity, sympathetic nervous system, and endothelial cell metabolic activities which may contribute to higher global cognition.

Regional difference in prefrontal oxygenation before and during overground walking in humans: a wearable multichannel NIRS study.

Using wireless multichannel near-infrared spectroscopy, regional difference in cortical activity over the prefrontal cortex (PFC) was examined before and during overground walking and in response to changes in speed and cognitive demand. Oxygenated-hemoglobin concentration (Oxy-Hb) as index of cortical activity in ventrolateral PFC (VLPFC), dorsolateral PFC (DLPFC), and frontopolar cortex (FPC) was measured in 14 subjects, whereas heart rate was measured as estimation of exercise intensity in six subjects. The impact of mental imagery on prefrontal Oxy-Hb was also explored. On both sides, Oxy-Hb in VLPFC, DLPFC, and lateral FPC was increased before the onset of normal-speed walking, whereas Oxy-Hb in medial FPC did not respond before walking onset. During the walking, Oxy-Hb further increased in bilateral VLPFC, whereas Oxy-Hb was decreased in DLPFC and lateral and medial FPC. Increasing walking speed did not alter the increase in Oxy-Hb in VLPFC but counteracted the decrease in Oxy-Hb in DLPFC (but not in lateral and medial FPC). Treadmill running evoked a greater Oxy-Hb increase in DLPFC (n = 5 subjects). Furthermore, increasing cognitive demand during walking, by deprivation of visual feedback, counteracted the decrease in Oxy-Hb in DLPFC and lateral and medial FPC, but it did not affect the increase in Oxy-Hb in VLPFC. Taken together, the profound and localized Oxy-Hb increase is a unique response for the VLPFC. The regional heterogeneity of the prefrontal Oxy-Hb responses to natural overground walking was accentuated by increasing walking speed or cognitive demand, suggesting functional distinction within the PFC.

Prefrontal cortex activation during incremental inspiratory loading in healthy participants.

We aimed to investigate whether changes in prefrontal cortex (PFC) oxyhemoglobin (O2Hb) and deoxyhemoglobin (HHb) associates with inspiratory muscle effort during inspiratory threshold loading (ITL) in healthy participants. Participants performed an incremental ITL. Breathing pattern, partial pressure of end-tidal CO2 (PETCO2), mouth pressure and O2Hb and HHb over the right dorsolateral PFC, sternocleidomastoid (SCM), and diaphragm/intercostals (Dia/IC) were monitored. Fourteen healthy participants (8 men; 29 ± 5 years) completed testing. Dyspnea was higher post- than pre-ITL (5 ± 1 vs. 0 ± 1, respectively; P<0.05). PFC O2Hb increased (P < 0.001) and HHb decreased (P = 0.001) at low loads but remained stable with increasing ITL intensities. PFC total hemoglobin increased at task failure compared to rest. SCM HHb increased throughout increasing intensities. SCM and Dia/IC total hemoglobin increased in the at task failure compared to rest. PETCO2 did not change (P = 0.528). PFC is activated early during the ITL but does not show central fatigue at task failure despite greater dyspnea and an imbalance of SCM oxygen demand and delivery.

Acute L-Citrulline Supplementation Increases Nitric Oxide Bioavailability but Not Inspiratory Muscle Oxygenation and Respiratory Performance.

The present study aimed to investigate whether acute L-citrulline supplementation would affect inspiratory muscle oxygenation and respiratory performance. Twelve healthy males received 6 g of L-citrulline or placebo in a double-blind crossover design. Pulmonary function (i.e., forced expired volume in 1 s, forced vital capacity and their ratio), maximal inspiratory pressure (MIP), fractional exhaled nitric oxide (NO•), and sternocleidomastoid muscle oxygenation were measured at baseline, one hour post supplementation, and after an incremental resistive breathing protocol to task failure of the respiratory muscles. The resistive breathing task consisted of 30 inspirations at 70% and 80% of MIP followed by continuous inspirations at 90% of MIP until task failure. Sternocleidomastoid muscle oxygenation was assessed using near-infrared spectroscopy. One-hour post-L-citrulline supplementation, exhaled NO• was significantly increased (19.2%; p < 0.05), and this increase was preserved until the end of the resistive breathing (16.4%; p < 0.05). In contrast, no difference was observed in the placebo condition. Pulmonary function and MIP were not affected by the L-citrulline supplementation. During resistive breathing, sternocleidomastoid muscle oxygenation was significantly reduced, with no difference noted between the two supplementation conditions. In conclusion, a single ingestion of 6 g L-citrulline increased NO• bioavailability but not the respiratory performance and inspiratory muscle oxygenation.

A randomized-controlled neurofeedback trial in adult attention-deficit/hyperactivity disorder.

Attention-deficit/hyperactivity disorder (ADHD) is a childhood onset disorder persisting into adulthood for a large proportion of cases. Neurofeedback (NF) has shown promising results in children with ADHD, but randomized controlled trials in adults with ADHD are scarce. We aimed to compare slow cortical potential (SCP)- and functional near-infrared spectroscopy (fNIRS) NF to a semi-active electromyography biofeedback (EMG-BF) control condition regarding changes in symptoms and the impact of learning success, as well as changes in neurophysiological parameters in an adult ADHD population. Patients were randomly assigned to SCP-NF (n = 26), fNIRS-NF (n = 21) or EMG-BF (n = 20). Outcome parameters were assessed over 30 training sessions (pre, intermediate, post) and at 6-months follow-up (FU) including 3 booster sessions. EEG was recorded during two auditory Go/NoGo paradigms assessing the P300 and contingent negative variation (CNV). fNIRS measurements were conducted during an n-back- as well as a Go/NoGo task. All three groups showed equally significant symptom improvements suggesting placebo- or non-specific effects on the primary outcome measure. Only when differentiating between learners and non-learners, fNIRS learners displayed stronger reduction of ADHD global scores compared to SCP non-learners at FU, and fNIRS learners showed specifically low impulsivity ratings. 30.8% in the SCP-NF and 61.9% of participants in the fNIRS-NF learned to regulate the respective NF target parameter. We conclude that some adults with ADHD learn to regulate SCP amplitudes and especially prefrontal hemodynamic activity during NF. We did not find any significant differences in outcome between groups when looking at the whole sample. When evaluating learners only, they demonstrate superior effects as compared to non-learners, which suggests specific effects in addition to non-specific effects of NF when learning occurs.

Subjective Effects of Inhaling Kuromoji Tea Aroma.

Teas and various herbal teas are well-known beverages and are commonly consumed around the world. In this study, we focused on kuromoji tea. Kuromoji is a deciduous shrub of the Lauraceae family, and the plucked leaves and branches have been drunk as a tea in production areas for a long time. However, no studies have investigated the subjective and physiological effects of kuromoji tea. In this study, the effects of kuromoji tea were examined on the basis of the measurements of heart rate variability and cerebral blood flow, core body temperature and subjective assessments. Moreover, the results of this study showed that a pleasant subjective feeling could be obtained by sniffing the aroma of kuromoji teas, especially tea leaves. It was also found that the aroma of kuromoji teas has the potential to stimulate saliva secretion and increase subjective and physiological excitements in the oral cavity. 1,8-Cineole, linalool, terpinen-4-ol, carvone and geraniol were determined in both kuromoji leaves and branches. In this study, the beneficial effects of kuromoji teas when drunk conventionally were investigated.

Significance of the ability to differentiate emotional prosodies for the early diagnosis and prognostic prediction of mild hypoxic-ischemic encephalopathy in neonates.

BACKGROUND: Perinatal brain injury affects around 300,000 neonates in China each year, early diagnosis and active intervention are also crucial for timely treatment and better prognoses. As hearing is the earliest as well as the most sensitive sense to develop in neonates, we propose that the ability to differentiate among different emotional prosodies may differ between neonates with and without brain injuries. METHODS: We enrolled full-term neonates admitted to the neonatology department of Peking University First Hospital from January 2016 to December 2016, conducted functional near-infrared spectroscopy (fNIRS) monitoring within 24 hr of admission, and analyzed changes in oxyhemoglobin (ΔHbO2 ) and deoxyhemoglobin (ΔHb) to study the ability of neonates to differentiate among emotional prosodies. The neonates were followed up to 36 months for neurological outcome evaluation. RESULTS AND CONCLUSIONS: We found that neonates showed the early ability to differentiate among emotional prosodies, responding most sensitively to positive emotions, and this ability may have been impaired following brain injury.

Dietary flavanols improve cerebral cortical oxygenation and cognition in healthy adults.

Cocoa flavanols protect humans against vascular disease, as evidenced by improvements in peripheral endothelial function, likely through nitric oxide signalling. Emerging evidence also suggests that flavanol-rich diets protect against cognitive aging, but mechanisms remain elusive. In a randomized double-blind within-subject acute study in healthy young adults, we link these two lines of research by showing, for the first time, that flavanol intake leads to faster and greater brain oxygenation responses to hypercapnia, as well as higher performance only when cognitive demand is high. Individual difference analyses further show that participants who benefit from flavanols intake during hypercapnia are also those who do so in the cognitive challenge. These data support the hypothesis that similar vascular mechanisms underlie both the peripheral and cerebral effects of flavanols. They further show the importance of studies combining physiological and graded cognitive challenges in young adults to investigate the actions of dietary flavanols on brain function.

Increased prefrontal oxygenation prior to and at the onset of over-ground locomotion in humans.

Our laboratory has reported with near-infrared spectroscopy (NIRS) that prefrontal oxygenated-hemoglobin concentration (Oxy-Hb), measured as index of regional cerebral blood flow, increased before and at the onset of arbitrary (i.e., noncued) ergometer exercise in a laboratory environment. In the current study, we hypothesized that naturally occurring over-ground locomotion, despite "very light" motor effort, as indicated by a Borg scale of 8.0 ± 0.3, likewise causes preexercise activation of the prefrontal cortex. Using wireless NIRS, we examined in this study how early and to what extent prefrontal activity changed before the onset of arbitrary walking in 13 subjects. Prefrontal Oxy-Hb increased 2 s before the onset of arbitrary walking, and the increased Oxy-Hb reached a peak at 5 s from walking onset. The preexercise and initial increase in prefrontal Oxy-Hb was absent when over-ground walking was forced to start by cue. The difference in the Oxy-Hb response between arbitrary and cued start, which was considered to be related to central command, became significant 2 s before walking onset, preceding the difference in the heart rate (HR) response by 8 s. This demonstrated a positive relationship with the HR difference in 69% of subjects. Imagery of arbitrary walking was, likewise, able to increase prefrontal oxygenation to the same extent as actual walking. Thus, it is likely that prefrontal oxygenation increases before the onset of naturally occurring walking in daily life, despite "very light" effort. The increased prefrontal oxygenation may contribute at least partly to cardiac adjustment, synchronized with the beginning of motor performance.NEW & NOTEWORTHY We found using wireless near-infrared spectroscopy that prefrontal oxygenation increased before the onset of arbitrary over-ground walking, whereas the preexercise increase was absent when walking was suddenly started by cue. The difference in prefrontal oxygenation between start modes (considered related to central command) preceded heart rate response variances and demonstrated a positive relationship with the difference in heart rate. The central command-related prefrontal activity may contribute to cardiac adjustment, synchronized with the beginning of over-ground walking.

Photobiomodulation effect on local hemoglobin concentration assessed by near-infrared spectroscopy in humans.

Exposure of biological tissue to photobiomodulation therapy (PBMT) seems to increase the oxygen availability and mitochondrial electrochemical activity. With the advancement of new technologies, such as near-infrared spectroscopy (NIRS), information can be obtained about the balance between oxygen utilization and delivery by assessing local oxy- ([O2Hb]) and deoxy-myohemoglobin ([HHb]) concentrations, both measured in micromolars (µM). Consequently, NIRS can be used to study ("in vivo") PBMT effects on the oxidative system, including oxygen availability. Thus, the main objective of the present study was to use NIRS to investigate the acute effects of PBMT by light-emitting diode (LED) on the oxygen delivery and utilization in humans. Twelve healthy young participants were treated with a LED device (850 nm, 50 mW, 2 J) and placebo applied over the proximal third of the flexor carpi ulnaris muscle of the left or right forearm selected in a random order. The LED was applied in direct contact with skin and the device was switched on for 40 s in 4 different interventions (I1, I2, I3 and I4) with a 3-min interval between interventions. The placebo condition was considered as the period before the first PBMT. The NIRS device was used to evaluate the relative changes in [O2Hb] and [HHb] before and after placebo and interventions. We found that PBMT statistically increased the [O2Hb] in 0.39 µM. These results demonstrate the potential of PBMT to increase oxygen availability.

Using fMRI to investigate the potential cause of inverse oxygenation reported in fNIRS studies of motor imagery.

Motor imagery (MI) is a commonly used cognitive task in brain-computer interface (BCI) applications because it produces reliable activity in motor-planning regions. However, a number of functional near-infrared spectroscopy (fNIRS) studies have reported the unexpected finding of inverse oxygenation: increased deoxyhemoglobin and decreased oxyhemoglobin during task periods. This finding questions the reliability of fNIRS for BCI applications given that MI activation should result in a focal increase in blood oxygenation. In an attempt to elucidate this phenomenon, fMRI and fNIRS data were acquired on 15 healthy participants performing a MI task. The fMRI data provided global coverage of brain activity, thus allowing visualization of all potential brain regions activated and deactivated during task periods. Indeed, fMRI results from seven subjects included activation in the primary motor cortex and/or the pre-supplementary motor area during the rest periods in addition to the expected activation in the supplementary motor and premotor areas. Of these seven subjects, two showed inverse oxygenation with fNIRS. The proximity of the regions showing inverse oxygenation to the motor planning regions suggests that inverse activation detected by fNIRS may likely be a consequence of partial volume errors due to the sensitivity of the optodes to both primary motor and motor planning regions.

Age-related differences in the within-session trainability of hemodynamic parameters: a near-infrared spectroscopy-based neurofeedback study.

Neurofeedback studies revealed that the hemodynamic response as assessed with near-infrared spectroscopy (NIRS) can be voluntarily modulated. However, the hemodynamic response generally changes with age, and it remains unclear whether age-related differences in the hemodynamic response affect the trainability of brain signals. In the present study, N = 24 healthy young adults (mean age: 23 years; age range: 21-28 years) and N = 19 healthy older individuals (mean age: 69 years; age range: 60-84 years) performed one NIRS-based neurofeedback session. Half of all participants either tried to increase deoxygenated hemoglobin (deoxy-Hb) or decrease oxygenated hemoglobin over the inferior frontal gyrus (IFG) during imagery of swallowing movements. In addition, the hemodynamic response during motor imagery and execution of swallowing without real-time feedback was compared between groups. Young and older adults showed an opposite NIRS signal change during motor imagery, probably indicating a reduced movement inhibition ability in older individuals. Age-related differences in the trainability of the hemodynamic response during neurofeedback training were observed, too. Young participants were able to decrease oxygenated hemoglobin and increase deoxy-Hb over the bilateral IFG, whereas older participants were mainly able to increase deoxy-Hb over the left IFG. Our results provide evidence of age-related differences in the within-session trainability of the hemodynamic response as assessed with NIRS and have an impact on the application of NIRS-based real-time feedback.

Contrast Baths, Intramuscular Hemodynamics, and Oxygenation as Monitored by Near-Infrared Spectroscopy.

CONTEXT:: Contrast baths (CB) is a thermal treatment modality used in sports medicine, athletic training, and rehabilitation settings. Proposed physiological effects of CB include increasing tissue blood flow and oxygenation and decreasing tissue swelling and edema to promote better healing, improved limb function, and quicker recovery. OBJECTIVE:: To investigate the physiological effects of CB on the intramuscular hemodynamics and oxygenation of the lower leg muscles using near-infrared spectroscopy (NIRS), an optical method for monitoring changes in tissue oxygenated (O2Hb), deoxygenated (HHb), and total hemoglobin (tHb) as well as tissue oxygen saturation index (TSI%). DESIGN:: Descriptive laboratory study. PATIENTS OR OTHER PARTICIPANTS:: Ten healthy men and women with a mean age of 29 (range = 17 ± 42) years, mean body mass index of 24.6 ± 3.2, and mean adipose tissue thickness of 6.4 ± 2.2 mm. INTERVENTION(S):: Conventional CB (10-minute baseline, 4 : 1-minute hot : cold ratio) was applied to the left lower leg. MAIN OUTCOME MEASURE(S):: Changes in chromophore concentrations of O2Hb, HHb, tHb, and TSI% of the gastrocnemius muscle were monitored during 10 minutes of baseline measurement, a 30-minute CB protocol, and 10 minutes of recovery using a spatially resolved NIRS. RESULTS:: After a 30-minute CB protocol, increases ( P < .05) in tissue O2Hb (7.4 ± 4 µM), tHb (7.6 ± 6.1 µM), and TSI% (3.1% ± 2.3%) were observed as compared with baseline measures. CONCLUSIONS:: Application of CB induced a transient change in the hemodynamics and oxygenation of the gastrocnemius muscle in healthy individuals. The effect of CB application in improving tissue hemodynamics and oxygenation may, therefore, support the therapeutic benefits of CB in the treatment of muscle injuries.

An increase in prefrontal oxygenation at the start of voluntary cycling exercise was observed independently of exercise effort and muscle mass.

PURPOSE: We have reported using near-infrared spectroscopy that an increase in prefrontal oxygenated-hemoglobin concentration (Oxy-Hb) at the start of cycling exercise has relation to central command, defined as a feedforward signal descending from higher brain centers. The final output of central command evokes the exercise effort-dependent cardiovascular responses. If the prefrontal cortex may output the final signal of central command toward the autonomic nervous system, the prefrontal oxygenation should increase depending on exercise effort. To test the hypothesis, we investigated the effects of exercise intensity and muscle mass on prefrontal oxygenation in 13 subjects. METHODS: The subjects performed one- or two-legged cycling at various relative intensities for 1 min. The prefrontal Oxy-Hb and cardiovascular variables were simultaneously measured during exercise. RESULTS: The increase in cardiac output and the decrease in total peripheral resistance at the start of one- and two-legged cycling were augmented in proportion to exercise intensity and muscle mass recruitment. The prefrontal Oxy-Hb increased at the start of voluntary cycling, while such increase was not developed during passive cycling. Mental imagery of cycling also increased the prefrontal Oxy-Hb, concomitantly with peripheral muscle vasodilatation. However, the increase in prefrontal Oxy-Hb at the start of voluntary cycling seemed independent of exercise intensity and muscle mass recruitment. CONCLUSIONS: It is likely that the increased prefrontal activity at the start of cycling exercise is not representative of the final output signal of central command itself toward the autonomic nervous system but may trigger neuronal activity in the caudal brain responsible for the generation of central command.

Physiological Effects of Visual Stimulation with Forest Imagery.

This study was aimed to clarify the physiological effects of visual stimulation using forest imagery on activity of the brain and autonomic nervous system. Seventeen female university students (mean age, 21.1 ± 1.0 years) participated in the study. As an indicator of brain activity, oxyhemoglobin (oxy-Hb) concentrations were measured in the left and right prefrontal cortex using near-infrared time-resolved spectroscopy. Heart rate variability (HRV) was used as an indicator of autonomic nervous activity. The high-frequency (HF) component of HRV, which reflected parasympathetic nervous activity, and the ratio of low-frequency (LF) and high-frequency components (LF/HF), which reflected sympathetic nervous activity, were measured. Forest and city (control) images were used as visual stimuli using a large plasma display window. After sitting at rest viewing a gray background for 60 s, participants viewed two images for 90 s. During rest and visual stimulation, HRV and oxy-Hb concentration in the prefrontal cortex were continuously measured. Immediately thereafter, subjective evaluation of feelings was performed using a modified semantic differential (SD) method. The results showed that visual stimulation with forest imagery induced (1) a significant decrease in oxy-Hb concentrations in the right prefrontal cortex and (2) a significant increase in perceptions of feeling "comfortable," "relaxed," and "natural."

Study on mechanism of release oxygen by photo-excited hemoglobin in low-level laser therapy.

According to the calculated results on the charge distribution of oxygenated heme and deoxygenated heme, and based on the theory of electron excitations in photo-acceptor molecules and the absorption spectra of hemoglobin, it is found that low-level laser within the waveband of about 800-1060 nm can promote the release of oxygen from oxyhemoglobin and improve the oxygen supply of capillaries to surrounding tissues. Furthermore, the reasons have been explained that why the low-level laser at a wavelength of 830 nm is better in the treatment on burn injury and stimulation of hair growth. We also explained why the near-infrared laser of 1064 nm is applied to the forehead to improve cerebral oxygenation in healthy humans. Finally, according to comparison of atomic charge distribution in heme before and after bound to small molecule of carbon monoxide or nitric oxide, it could be inferred that the low-level laser with an appropriate wavelength can promote the carbon monoxide hemoglobin and nitric oxide hemoglobin to dissociate the carbon monoxide molecules and the nitric oxide molecules. This may be used for adjuvant therapy of carbon monoxide poisoning or nitric oxide poisoning.

Physiological effects of viewing fresh red roses.

OBJECTIVES: The present study aimed to clarify the effects of viewing fresh roses on prefrontal cortex activity, autonomic nervous activity and subjective assessments of psychological relaxation. DESIGN: A crossover design, in which each experimental group crosses over from one treatment to another, was used. SETTING AND INTERVENTIONS: A total of 15 female university students (mean age 21.7±1.1years) viewed fresh roses for 3min; the control consisted of no experimental stimulus. MAIN OUTCOME MEASURES: Physiological effects on prefrontal cortex activity were determined by near-infrared time-resolved spectroscopy, which was assessed by measuring oxyhemoglobin (oxy-Hb) concentration in the left and right prefrontal cortex; effects on autonomic nervous activity were assessed by measuring heart rate variability (HRV) and heart rate. Modified semantic differential method and Profile of Mood States were used to determine subjective evaluations. RESULTS: Viewing roses induced: 1) a significant decrease in oxy-Hb concentrations in the right prefrontal cortex; 2) a marginally significant decrease in ln[LF/(LF+HF)] of HRV, which is associated with sympathetic nervous activity; 3) a significant increase in perceptions of feeling 'comfortable,' 'relaxed,' and 'natural;' and 4) a significant improvement in mood state. CONCLUSIONS: These findings indicate that visual stimulation with roses induces physiological and psychological relaxation.

Effects of Visual Stimulation with Bonsai Trees on Adult Male Patients with Spinal Cord Injury.

Nature therapy has been demonstrated to induce physiological relaxation. The psychophysiological effects of nature therapy (stimulation with bonsai trees) on adult male patients with spinal cord injury (SCI) were examined. Oxyhemoglobin concentration changes in the prefrontal cortex were measured using near-infrared spectroscopy, and heart rate variability was analyzed. Psychological responses were evaluated using the modified semantic differential method and Profile of Mood States (POMS) subscale scores. Visual stimulation of adult male patients with SCI elicited significantly decreased left prefrontal cortex activity, increased parasympathetic nervous activity, decreased sympathetic nervous activity, increased positive feelings, and resulted in lower negative POMS subscale scores. Nature therapy can lead to a state of physiological and psychological relaxation in patients with SCI.