oxy-Hb Levels Research Articles

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Several studies have shown that various types of cognitive processing exist and exert different effects on brain activity. However, when a subject performs the same task, whether the task involves processing or not, such as in mental calculation or with a calculator, the different influences on the brain remain unclear. The purpose of this study was to examine whether the influence of cortical activation when performing mental calculation and using a calculator have different effects on the brain. Fifteen healthy, right-handed participants (mean age, 26.3 ± 8.5 years; 12 men, 27.7 ± 9.0 years; 3 women, 20.6 ± 1.1 years) were recruited as subjects. We measured oxygenated hemoglobin (oxy-Hb) levels while subjects performed subtraction tasks by mental calculation or using a calculator (3 min each). Measurements were made at the frontal lobe and temporal lobe. In both lobes, oxy-Hb level was significantly increased during mental calculation. Locations showing significantly increased oxy-Hb in mental calculation were the prefrontal cortex in the frontal lobe and supramarginal gyrus in the temporal lobe. These results suggest that the brain responds differently to tasks in mental calculation and using a calculator. We hypothesized that using the electronic calculator needs fewer neural networks than performing mental calculation. In recent years, thanks to the development of machines, many tasks have been automated, making our lives easier and more convenient. Our results may provide one example that the developments of modern technology influence brain function.

NIRSを用いた水平振動時の脳賦活分析

Ride comfort is an important issue in improving passenger comfort in an automobile. Quantifying ride comfort is difficult because it affects a person's emotions and physiology. In this paper, we measure brain activities using near-infrared spectroscopy to clarify the features of brain activities while sensing vibration. Hopefully, the results obtained in this study can be applied to quantify subjective evaluation for ride comfort. Moreover, we measured brain activities while sensing vibrations which are uncomfortable and not uncomfortable vibrations. Uncomfortable and not uncomfortable vibrations were determined on the basis of sensory evaluation. Results showed that the concentration of oxygenated hemoglobin (oxy-Hb) levels in the prefrontal cortex change with the sense of vibration. In addition, during uncomfortable vibration, the oxy-Hb level declined more than that while sensing not uncomfortable vibrations. In addition, we measured brain activities while sensing a vibration which is divided over subject's feeling to the vibration and found that oxy-Hb of the subjects sensing uncomfortable vibration declined in the prefrontal cortex. Therefore, we infer that decline of oxy-Hb in the prefrontal cortex is relative to an uncomfortable feeling.

Prefrontal cortex activation is associated with a discrepancy between self- and observer-rated depression severities of major depressive disorder: A multichannel near-infrared spectroscopy study

BackgroundStudies on major depressive disorder (MDD) show that the degree of correlation between the Beck Depression Inventory (BDI) and Hamilton Depression Rating Scale (HAMD) varies widely. We aimed to determine whether this discrepancy reflects specific functional abnormalities in the frontotemporal cortex. MethodsMildly depressed or euthymic patients with MDD (n=52), including 21 patients with MDD with the discrepancy, i.e., those with low HAMD17 scores (≤13) but high BDI-II scores (>28), and 31 patients without the discrepancy, i.e., those with low HAMD17 scores and low BDI-II scores (≤28), participated in the study along with 48 control subjects. Regional changes of oxygenated hemoglobin (oxy-Hb) levels during a verbal fluency task (VFT) were monitored using a 52-channel near-infrared spectroscopy (NIRS) device. ResultsIn the frontotemporal regions, mean oxy-Hb changes induced by the VFT were significantly smaller in patients with MDD than in control subjects. In 5 channels within frontal regions, the increase in mean oxy-Hb levels was significantly greater in MDD patients with the BDI–HAMD discrepancy than in those without the discrepancy. In 6 channels within the frontal region of the patients with MDD, significant positive correlations were observed between mean oxy-Hb changes and BDI total scores (ρ=0.38–0.59; P<0.05, false discovery rate corrected). LimitationsOur findings required replication in severely depressed patients, particularly those with melancholia. ConclusionsThe distinct pattern of activation of the prefrontal cortex suggests that MDD with the BDI–HAMD discrepancy is pathophysiologically different from MDD without the discrepancy.

FNIRS suggests increased effort during executive access in ecstasy polydrug users.

Ecstasy use is associated with cognitive impairment, believed to result from damage to 5-HT axons. Neuroimaging techniques to investigate executive dysfunction in ecstasy users provide a more sensitive measure of cognitive impairment than behavioural indicators. The present study assessed executive access to semantic memory in ecstasy polydrug users and non-users. Twenty ecstasy polydrug users and 20 non-user controls completed an oral variant of the Chicago Word Fluency Test (CWFT), whilst the haemodynamic response to the task was measured using functional near-infrared spectroscopy (fNIRS). There were no between-group differences in many background measures including measures of sleep and mood state (anxiety, arousal, hedonic tone). No behavioural differences were observed on the CWFT. However, there were significant differences in oxy-Hb level change at several voxels relating to the left dorsolateral prefrontal cortex (DLPFC) and right medial prefrontal cortex (PFC) during the CWFT, indicating increased cognitive effort in ecstasy users relative to controls. Regression analyses showed that frequency of ecstasy use, total lifetime dose and amount used in the last 30 days was significant predictors of oxy-Hb increase at several voxels after controlling for alcohol and cannabis use indices. The results suggest that ecstasy users show increased activation in the PFC as a compensatory mechanism, to achieve equivalent performance to non-users. These findings are in agreement with much of the literature in the area which suggests that ecstasy may be a selective serotonin neurotoxin in humans.

Effects of self-action observation on standing balance learning: A change of brain activity detected using functional near-infrared spectroscopy.

Studies suggest that the observation of others' actions leads to enhanced motor skill learning. We examined whether others' or self-action observation is effective for standing balance learning. In addition, we examined cortical activation during action observation using functional near-infrared spectroscopy. Thirty-nine healthy young subjects were assigned randomly to the Control, Other-Observation (O-O), and Self-Observation (S-O) groups. The subjects learned to stand on a tilting platform while maintaining a horizontal position. The Control group alternated each trial with a rest period. The O-O and S-O groups were provided with information related to their performance during the rest period: the O-O group observed another person, while the S-O group observed their previous performance. Cortical activation was assessed by changes of hemoglobin oxygenation (oxyHb). A 2-way analysis of variance with repeated measures on balance performance revealed a significant difference in post-training (p < 0.05) and retention (p < 0.01) only in the S-O group. And an increase of oxyHb levels at post-training in the S-O group was observed in the supplementary motor area. Self-action observation improved standing balance and brain activity during training and at 24 h after training.

Estimated cerebral oxyhemoglobin as a useful indicator of neuroprotection in patients with post-cardiac arrest syndrome: a prospective, multicenter observational study.

IntroductionLittle is known about oxyhemoglobin (oxy-Hb) levels in the cerebral tissue during the development of anoxic and ischemic brain injury. We hypothesized that the estimated cerebral oxy-Hb level, a product of Hb and regional cerebral oxygen saturation (rSO2), determined at hospital arrival may reflect the level of neuroprotection in patients with post-cardiac arrest syndrome (PCAS).MethodsThe Japan Prediction of neurological Outcomes in patients with Post cardiac arrest (J-POP) registry is a prospective, multicenter, cohort study to test whether rSO2 predicts neurologic outcomes after out-of-hospital cardiac arrest (OHCA). This study assessed a subgroup of consecutive patients who fulfilled the J-POP registry criteria and successfully achieved return of spontaneous circulation (ROSC) from OHCA. The primary outcome measure was the neurologic status at 90 days.ResultsWe analyzed data from 495 consecutive comatose survivors who were successfully resuscitated from OHCA, including 119 comatose patients with prehospital return of spontaneous circulation (ROSC; 24.0%) and 376 cardiac arrests at hospital arrival. In total, 75 patients (15.1%) presented with good neurologic outcomes. Univariate analysis revealed that the cerebral oxy-Hb levels were significantly higher in patients with good outcomes. Multivariate logistic regression using the backward-elimination method confirmed that the oxy-Hb level was a significant predictor of good neurologic outcomes (adjusted odds ratio, 1.27; 95% confidence interval (CI), 1.11 to 1.46). Analysis of the area under the receiver operating characteristic curve (AUC) revealed that an oxy-Hb cut-off of 5.5 provided optimal sensitivity and specificity for predicting good neurologic outcomes (AUC, 0.87; 95% CI, 0.83 to 0.91; sensitivity, 77.3%; specificity, 85.6%). The oxy-Hb level appeared to be an excellent prognostic indicator with significant advantages over rSO2 and base excess, according to AUC analysis. The significant trend for good neurologic outcomes was consistent, even in the subgroup of patients who achieved return of spontaneous circulation on hospital arrival (1st quartile, 0; 2nd quartile, 16.7%; 3rd quartile, 29.4%; 4th quartile, 53.3%; P < 0.05).ConclusionsThe cerebral oxy-Hb level may predict neurologic outcomes and is a simple and excellent indicator of neuroprotection in patients with PCAS.Trial registrationUMIN Clinical Trials Registry UMIN000005065. Registered 1 April 2011.

Acoustic Signals of a Dog and Cat Induce Hemodynamic Responses within the Human Brain

ABSTRACTThe objective of this study was to evaluate the response of the human frontal cortex when listening to cat meows and dog barks, accompanied with a non-verbal pictorial using an affective rating system that assesses the dimensions of valence and arousal. Each participant (24 students; 12 females and 12 males) sat individually in the middle of a room and listened to the sounds (cat meows, dog barks, and the sound of a train) through ceiling-mounted speakers with a near infrared spectroscopic (NIRS) device. Participants had significantly higher oxygenated hemoglobin (oxy-Hb) levels during the exposure to meows (p < 0.05) and barks (p < 0.01) compared with the train sound. A significant correlation was observed between the dimensions of valence and oxy-Hb activation when the participants listened to cat meows (r = 0.53, p < 0.017; Bonferroni correction). In conclusion, we found that the acoustic signals of companion animals lead to frontal cortex responses in humans, suggesting that their signals have an important function related to their long coexistence with people.

Experimental pain in the gingiva and its impact on prefrontal cortical hemodynamics: A functional near-infrared spectroscopy study

Evaluating alterations in brain activity in response to pain stimulus can help understand the mechanisms underlying pain perception. We measured oxygenated hemoglobin (oxy-Hb) levels using functional near-infrared spectroscopy (fNIRS) in order to assess prefrontal cortex activation after inducing a pain stimulus to the gingiva. Twenty-three right-handed, healthy male subjects (mean age: 29.3±3.6 years) were subjected to a mild pain stimulus to the tissue around the right maxillary central incisor. The periodontal pain stimulus (PPS) was elicited from a pocket probe, and a multi-channel fNIRS system with its accompanying 22-channel probes was used for measuring oxy-Hb levels. Mean oxy-Hb levels for each channel were calculated on the basis of values obtained at rest and during the PPS load, for 1min each. The change in oxy-Hb level was calculated by subtracting oxy-Hb at rest from oxy-Hb levels during PPS load. Oxy-Hb levels in each channel during both conditions were then compared using the paired t-test and Bonferroni correction. Pain stimulation caused oxy-Hb levels to decrease in virtually all areas of the prefrontal cortex, particularly, in the superior frontal gyrus, the middle frontal gyrus, and the orbital part of the superior, middle, and inferior frontal gyrus, on the brain side contralateral to the pain load. This measurement could prove beneficial as an index for objective pain evaluation.

Evaluating “Cosmetic Therapy” by Using Near-Infrared Spectroscopy

This study examined the effect of cosmetic therapy on frontal lobe activation as revealed by topographic near-infrared spectroscopy (NIRS). We evaluated emotional responses to a photograph of a face with/without makeup by 22 healthy female volunteers (mean age, 52 ± 10.5 years). The results of the first-round analysis showed a significant increase of oxy-Hb in the frontal lobe area when the subject looked at a photograph of herself made up as compared to not made up. In a later round of analysis, we divided the subjects into 2 groups having contrasting scores on the Profile of Mood States-Short Form Japanese version. One group was classed as “high vigor” (a common standard pattern) and the other as “low vigor” (depression-tendency pattern). The made-up/not made-up difference did not have any effect on the oxy-Hb level in the frontal lobe in the high vigor group. In contrast, makeup produced a significant increase in the oxy-Hb level over a wide frontal area in the low vigor group, which indicated widespread frontal lobe activation. This result indicates a beneficial effect of cosmetic therapy on the brain function of patients with depression and/ or dementia.

Brain Activity during Stereognostic Discrimination Using the Tongue Measured By Functional Near-Infrared Spectroscopy

We previously reported our investigation of the stereognostic ability of the tongue to recognize the shape and size of materials in the mouth and its clinical applications. In the present study, we observed brain activity while performing stereognostic discrimination using the tongue; the changes in levels of oxyhemoglobin (oxy-Hb), deoxyhemoglobin (deoxy-Hb), and total hemoglobin (total-Hb) in the frontal cortex area of 37 healthy individuals (18–75 years old) were measured using a functional near-infrared spectrometer with 45 channels. As an experimental task, the stereognostic test piece (TP) was placed on the center of the tongue dorsum, and subjects moved the TP for shape discrimination without letting it touch the teeth or gums. As a control task, subjects did not move the TP placed on the tongue. Stereognostic task-attributed changes in Hb levels were obtained by subtracting the Hb level of the control task from that of the experimental task. During the stereognostic task, oxy-Hb levels increased in the frontal cortex, including the prefrontal area, in most subjects. However, the results also demonstrated large individual variability. When the degree of change in Hb levels during the stereognostic task was mapped, it was found that the changes in the oxy- and total-Hb levels were similar, while the deoxy-Hb level did not change to the same degree. When subjects were divided into three groups, highly-, moderately- and mildlyincreased oxy-Hb levels, there was a significant negative correlation between age and degree of oxy-Hb level increase. The present study suggests stereognosis may be involved in several different information processing pathways, and that aging may also be a factor in the large variability we observed.

Reduction in Cortical Activation in the Sensorimotor Cortex during Motor Skill Learning of a Pursuit Rotor Task: A Functional Near-Infrared Spectroscopy Study

To investigate the cerebral mechanisms underlying learning of motor skills, we assessed serial changes of brain activation patterns during a pursuit rotor (PR) task in 12 right-handed healthy subjects using functional near-infrared spectroscopy (fNIRS). The subjects performed the task with their right hand for 15-s, alternated with a 30-s rest period, for 18 repetitions (cycles 1 to 18). Gains in motor skill were evaluated by recording the time for which the stylus remained on the target. Performance improved with repetition of the task. Task-related increases of oxygenated hemoglobin (oxy-Hb) were observed around the predicted location of the sensorimotor cortices on both hemispheres. The increased oxy-Hb levels appeared to reduce with repetition of the task in the channels covering the left sensorimotor area. Furthermore, there was a significant correlation between PR task performance gain and the oxy-Hb signal in the left and right sensorimotor areas. Our results suggest that cortical activation in the sensorimotor cortex reflects changes in a number of factors including sensory feedback processing, correct motor commands, and perceptual or cognitive function during learning of a PR task. Therefore, changes in contralateral sensorimotor cortical activation may serve as a motor sequence learning biomarker for rehabilitation purposes or the prediction of recovery.

Increased cerebral blood flow in the right frontal lobe area during sleep precedes self-awakening in humans.

BackgroundSome people can subconsciously wake up naturally (self-awakening) at a desired/planned time without external time stimuli. However, the underlying mechanism regulating this ability remains to be elucidated. This study sought to examine the relationship between hemodynamic changes in oxyhemoglobin (oxy-Hb) level in the prefrontal cortex and sleep structures during sleep in subjects instructed to self-awaken.ResultsFifteen healthy right-handed male volunteers with regular sleep habits participated in a consecutive two-night crossover study. The subjects were instructed to wake up at a specified time (“request” condition) or instructed to sleep until the morning but forced to wake up at 03:00 without prior notice (“surprise” condition). Those who awoke within ± 30 min of the planned waking time were defined as those who succeeded in self-awakening (“success” group). Seven subjects succeeded in self-awakening and eight failed.No significant differences were observed in the amounts of sleep in each stage between conditions or between groups. On the “request” night, an increase in oxy-Hb level in the right prefrontal cortex and a decrease in δ power were observed in the “success” group around 30 min before self-awakening, whereas no such changes were observed in the “failure” group. On the “surprise” night, no significant changes were observed in oxy-Hb level or δ power in either group.ConclusionsThese findings demonstrate a correlation between self-awakening and a pre-awakening increase in hemodynamic activation in the right prefrontal cortex, suggesting the structure’s contribution to time estimation ability.

Abstract 9991: The Product of Blood Hemoglobin and Regional Brain Oxygen Saturation is a Simple and Excellent Predictor for a Short-term Neurological Outcome in Patients with Post Cardiac Arrest Syndrome

BACKGROUND: It has been suggested that brain tissue oxygenation (rSO2) and blood hemoglobin (Hb) at hospital arrival are independently crucial for a prognosis in post cardiac arrest syndrome (PCAS). Although it has been reported that rSO2 correlates with Hb in perioperative patients, this correlation has not been demonstrated during CPR. The product of Hb and rSO2 might represent tissue oxy-Hb level, theoretically. Therefore, it was speculated that the product during CPR predicts neurological outcome in PCAS. AIM: To investigate the relationship between the product of Hb and rSO2 on hospital arrival and good neurological outcome at 30 days in PCAS patients. METHODS: The database of the J-POP registry (multicenter observational study) has prospectively enrolled 764 OHCA patients. Of these, 193 PCAS patients admitted to the wards after ROSC were included in this study. Hb and rSO2 were obtained during resuscitation within 3 min after hospital arrival. The neurological outcome was evaluated by CPC at 30 days, and CPC1 and 2 were defined as favorable neurological outcome. RESULTS: Among 193 PCAS patients, 27 presented favorable outcome (14%) and median [IQR] of Hb and rSO2 were 12.0g/dL [10.4-13.8] and 35% [15-55]. The favorable outcome group showed higher Hb (13.8+/-2.5 vs. 11.7+/-2.7, p&lt;0.001) and rSO2 (58.6 +/- 20.5 vs. 30.6+/-21.0, p&lt;0.001) compared to the unfavorable group. The ROC analysis revealed the product of Hb and rSO2 significantly predicted the favorable outcome (AUC, 0.861; optimal cut-off point, 411; sensitivity, 0.917; specificity, 0.709). When divided into 4 groups by quartile of the product of Hb and rSO2 level, the ratio of patients with favorable outcome was 4.2% in the first quartile (Q1, the product&lt;182), 4.2% in Q2 (183-257), 16.6% in Q3 (258-627), and 75.0% in Q4 (&gt;628), respectively (chi-square test: p&lt;0.001). CONCLUSIONS: The product of blood Hb and rSO2 level during resuscitation is a simple and excellent predictor for a 30-day neurological outcome in patients with PCAS.

Relationship between going outdoors daily and activation of the prefrontal cortex during verbal fluency tasks (VFTs) among older adults: A near-infrared spectroscopy study

This study sought to investigate the relationship between going outdoor daily and prefrontal cortex activation during execution of the VFT using near-infrared spectroscopy (NIRS) in community-dwelling older adults. Blood oxygenation changes in left and right prefrontal cortices were measured in twenty older adults (mean age 76.1±6.7 years) by NIRS during VFT performance. In this task, participants were required to pronounce as many nouns as possible beginning with the letters “Shi,” “I,” and “Re.” Changes in oxygenated hemoglobin (oxy-Hb) levels during the VFT were compared between two groups defined by the frequency of going outdoors: daily or non-daily within a week. Participants in both groups exhibited significantly increased oxy-Hb levels in the left and right prefrontal cortices during the VFT compared to a resting baseline condition. After controlling for age and gender, there were significant group-by-condition interactions on oxy-Hb levels with less activation during the execution of the VFT over both cortices in the non-daily group (left: F=4.76, p=0.04; right: F=6.32, p=0.02). These findings indicate that going outdoors daily is associated with increased activation in the prefrontal cortices during VFT performance in community-dwelling older adults.

Brain Activity Stimulated by Prism Adaptation Tasks Utilized for the Treatment of Unilateral Spatial Neglect: A Study with fNIRS.

We investigated the neurological basis for efficacy of prism adaptation therapy, which is used for the treatment of poststroke unilateral spatial neglect (USN). Study subjects were 6 USN-positive (+), 6 USN-negative patients, and 6 healthy volunteer control subjects. USN was identified by the Behavioural Inattention Test (BIT). During the tasks, brain activity was assessed with fNIRS via changes in oxyHb concentration per unit length. There was no significant difference in the number of errors in the task between the 3 groups. However, in the USN(+) group there was a significantly greater reduction in oxyHb levels in the right parietal association cortex during the prism adaptation task than in the other 2 groups (P < 0.05). There was an immediate improvement in USN symptoms as well as a significant increase in oxyHb levels during the prism adaptation in the channels covering the right frontal and parietal lobes in 2 patients in the USN(+) group (P < 0.05). This result suggested that decreased activity in the right parietal association cortex, which is related to spatial perception, during the prism adaptation task and task-induced reorganization of the right frontal and parietal areas were involved in improvement in USN symptoms.

Increased Cerebral Cortex Perfusion in Stroke Patients with Cognitive Disorder Following Cilostazol Administration, Two Cases Report

Objective: In our search for a new augmentation therapy for stroke patients, we administered cilostazol, an antiplatelet agent. Subjects: The patients suffered from mild hemiparesis or cognitive disorder showing reduced cerebral perfusion in the prefrontal cortex. Methods: We evaluated the functional cerebral blood flow (CBF) before and after the administration of cilostazol using near-infrared resonance spectroscopy (NIRS) during a verbal fluency task (VFT). Results: For the patient with cognitive disorder, statistically significant improvements were observed in the number of generated words in the VFT before and after administration of 50 mg cilostazol (p 0.05, Mann-Whitney U test). Another patient without cognitive disorder, however, showed no significant VFT improvement after administration of cilostazol. Effect size data revealed large or very large effects of cilostazol on brain activation (oxy-Hb levels) at the affected side prefrontal cortex for both patients. The patient with cognitive disorder showed significant improvement in VFT performance as well as an increase in bilateral prefrontal CBF after cilostazol administration. Discussion: These findings suggest that, for patients with cerebrovascular lesions suffering from cognitive disorder, cilostazol may be promising as a drug to improve cognitive function in addition to preventing recurrent cerebral infarction.

Correlation of prefrontal activity measured by near-infrared spectroscopy (NIRS) with mood, BDNF genotype and serum BDNF level in healthy individuals

Depression has been known to reduce the prefrontal activity associated with the execution of certain cognitive tasks, although whether a temporarily depressed or anxious mood in healthy individuals affects the prefrontal blood oxygen level during cognitive tasks is unknown. Combining the measurement of prefrontal activity with near-infrared spectroscopy (NIRS) and the two cognitive tasks, namely the letter version of the verbal fluency test (VFT-l) and the Stroop test, we measured the effect of a depressed or anxious mood and gender on the changes in the prefrontal oxygenated hemoglobin (Oxy-Hb) levels during those cognitive tests in healthy individuals. Depressed mood or anxious mood was assessed by the Hospital Anxiety and Depression Scale (HADS). Thereby we aimed to explore the possibility of NIRS measurement for detecting the early subclinical manifestation of major depression. Moreover, we examined the possible relationships between prefrontal activation and the functional Val66Met polymorphisms of the brain derived neurotropic factor (BDNF) gene and serum BDNF level. As a result, the increased prefrontal Oxy-Hb levels during cognitive tasks were significantly correlated with the severity of depressed mood in males. The course of the prefrontal Oxy-Hb increase was different depending on the cognitive tasks, i.e., the VFT-l or the Stroop test, in both genders. Correlations of BDNF genotype and serum BDNF level with the prefrontal Oxy-Hb levels during those cognitive tasks were negative. Our results suggest that the early subclinical manifestation of depressed mood in males might be detected by the NIRS measurement, which is not correlated with the individual properties of BDNF.

Water Immersion to the Femur Level Affects Cerebral Cortical Activity in Humans: Functional Near-Infrared Spectroscopy Study

Water immersion is widely used in physiotherapy and may even improve the functional outcomes of hemiplegic patients after stroke. To investigate the cortical responses to water immersion, functional near-infrared spectroscopy (fNIRS) was used to measure cortical activations in the primary somatosensory area (S1), parietal association area (PAA), supplementary motor area (SMA), and primary motor area (M1). Nine healthy adult males were rested in a sitting position for 15 min with simultaneous measurements of fNIRS, blood pressure, and skin temperature. The fNIRS signal and other physiological parameters were measured under three conditions, the non-immersed condition (baseline control), as the immersion tank was filling with water (pouring water condition), and during sustained water immersion. Each condition lasted for 5 min. The water level was allowed to reach the femur, and during the experiment, room and water temperatures were maintained at 34°C. Oxygenated hemoglobin (oxyHb) concentrations in the S1, PAA, SMA, and M1 remained stable during baseline recording but gradually increased during water pouring and immersion. Significantly higher oxyHb levels were observed in S1 at 20 s after the onset of water immersion condition and in the PAA at 40 s. Subsequently, oxyHb levels in the SMA and M1 increased significantly 100 s after the onset of water immersion condition. In contrast, no significant changes in blood pressure, heart rate, or skin temperature were observed. Water immersion resulted in increased activity in both sensory and motor areas of cortex as measured by non-invasive fNIRS. Water immersion may enhance the efficacy of physical therapy by providing background activation to affected areas of the cortex, thereby enhancing signal processing and learning.

Parietal and temporal activity during a multimodal dance video game: An fNIRS study

Using functional near infrared spectroscopy (fNIRS) we studied how playing a dance video game employs coordinated activation of sensory-motor integration centers of the superior parietal lobe (SPL) and superior temporal gyrus (STG). Subjects played a dance video game, in a block design with 30 s of activity alternating with 30 s of rest, while changes in oxy-hemoglobin (oxy-Hb) levels were continuously measured. The game was modified to compare difficult (4-arrow), simple (2-arrow), and stepping conditions. Oxy-Hb levels were greatest with increased task difficulty. The quick-onset, trapezoidal time-course increase in SPL oxy-Hb levels reflected the on-off neuronal response of spatial orienting and rhythmic motor timing that were required during the activity. Slow-onset, bell-shaped increases in oxy-Hb levels observed in STG suggested the gradually increasing load of directing multisensory information to downstream processing centers associated with motor behavior and control. Differences in temporal relationships of SPL and STG oxy-Hb concentration levels may reflect the functional roles of these brain structures during the task period. NIRS permits insights into temporal relationships of cortical hemodynamics during real motor tasks.

P03-390 - One night sleep restriction impairs the cortical oxygenation responses

IntroductionSleep restriction has adverse effects on performance and neurobehavioral function. However, the mechanism of impaired performance and neurobehavioral function has not been studied yet.ObjectivesWe examined the effect of insufficient sleep on cerebral blood flow and cognitive function in 8 healthy adults (mean age 22.4 years).MethodsAll participants were in bed for 8 h (sufficient sleep), and for &lt; 4 h (insufficient sleep). The oxyhemoglobin (oxyHb) level by a word fluency task was measured with a near-infrared spectroscopy recorder on the morning following sufficient and insufficient sleep periods. Wisconsin card sorting test (WCST), continuous performance test (CPT) and N-back test were evaluated on the same days.ResultsThe peak oxyHb level was significantly lower in the left and right frontal lobes after insufficient sleep than after sufficient sleep (left: 0.25 ± 0.10 vs. 0.70 ± 0.29 mmol, P &lt; 0.05; right: 0.23 ± 0.13 vs. 0.73 ± 0.22 mmol, P &lt; 0.05). There was no significant difference in the number of words generated during the word fluency task between sufficient and insufficient sleep states. The percentage of correct responses on CPT after insufficient sleep was significantly lower than that after sufficient sleep (86.6 ± 10.2 vs. 96.0 ± 4.9%, P &lt; 0.05). The reaction time of WCST was significantly longer after insufficient sleep than after sufficient sleep (76.6 ± 13.4 vs. 70.6 ± 16.2 sec, P &lt; 0.05).ConclusionsOne night sleep restriction decreased the concentration changes of oxyHb in brain tissue, leading to impaired cognitive function.