Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 16 de 16
Filter
Add more filters










Publication year range
2.
Melanoma Res ; 29(5): 501-509, 2019 10.
Article in English | MEDLINE | ID: mdl-30575644

ABSTRACT

In several cancers, tumor progression is associated with the infiltration of tumor-associated macrophages (TAMs). The aim was to evaluate the prognostic significance of expression of CD163 and CD68 (TAMs' markers) and their correlation with vascular endothelial growth factor (VEGF) and cyclooxygenase-2 (COX-2) expression in cutaneous melanoma. Diagnostic tissues from 102 patients of cutaneous melanoma were evaluated by immunohistochemistry for their CD68, CD163, VEGF, and COX-2 expression. Correlations between the proteins were then investigated. Clinicopathological features, overall survival (OS), and progression-free survival were analyzed in terms of the expression of these proteins. CD163, but not CD68, expression correlated with VEGF and COX-2 expression. High expression for CD163 was associated with a deeper Breslow thickness and an advanced stage of the disease. High expression of CD163 was associated with lower OS. No significant differences were noted in CD68 expression between the clinicopathological variables and the OS. COX-2 expression was associated with a deeper Breslow thickness and a higher frequency of lymph node involvement. Multivariate analysis revealed that CD163 expression and COX-2 expression were independent prognostic markers of lower survival outcomes. Our data confirmed that CD163 expression provides independent prognostic information in cutaneous melanoma. The correlation of CD163 with VEGF and COX-2 expression suggests various tumor-promoting actions of CD163-positive TAMs.


Subject(s)
Antigens, CD/metabolism , Antigens, Differentiation, Myelomonocytic/metabolism , Cyclooxygenase 2/metabolism , Gene Expression Regulation, Neoplastic , Melanoma/diagnosis , Receptors, Cell Surface/metabolism , Skin Neoplasms/metabolism , Vascular Endothelial Growth Factor A/metabolism , Adult , Aged , Aged, 80 and over , Disease Progression , Disease-Free Survival , Female , Humans , Lymphatic Metastasis , Male , Melanoma/metabolism , Middle Aged , Multivariate Analysis , Prognosis , Treatment Outcome
3.
Melanoma Res ; 28(5): 423-434, 2018 10.
Article in English | MEDLINE | ID: mdl-29634635

ABSTRACT

Interactions between immune cells and tumor cells play an important role in tumor progression. We evaluated patterns of tumor-infiltrating lymphocytes (TILs) and programmed death-1 (PD-1) expression in acral and nonacral cutaneous melanoma, and determined their effects on clinicopathological characteristics and biologic responses. We identified 122 cases of cutaneous melanoma, of which 39 were cases of non-nail unit acral melanoma (NNUAM), 35 were cases of nail unit melanoma (NUM), and 48 were cases of nonacral melanoma. Clinicopathological features and survival outcomes were analyzed according to the scores for TILs and PD-1 expression in intratumoral and peritumoral compartments. The effects of the presence of TILs and PD-1 expression on various clinicopathological factors differed according to the clinical subtypes of cutaneous melanoma. The frequency of intratumoral TILs and PD-1 expression were lower in NUM than in the other two subtypes. The density of peritumoral PD-1 was significantly higher in NNUAM. In NUM and nonacral melanoma, a low density of intratumoral TILs and PD-1 was associated with a deeper Breslow thickness and the presence of a vertical growth phase. In NNUAM, a high density of peritumoral TILs and PD-1 was associated with a shallower Breslow thickness and less frequent extracutaneous dissemination. In NNUAM, a high density of peritumoral PD-1 was associated with a better prognosis. This study suggests that the effects of PD-1+ TILs on biological activity differ according to the clinical subtypes of cutaneous melanoma.


Subject(s)
Lymphocytes, Tumor-Infiltrating/metabolism , Melanoma/genetics , Programmed Cell Death 1 Receptor/metabolism , Skin Neoplasms/genetics , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Melanoma/pathology , Middle Aged , Skin Neoplasms/pathology , Young Adult , Melanoma, Cutaneous Malignant
4.
Pediatr Dermatol ; 30(6): e226-7, 2013.
Article in English | MEDLINE | ID: mdl-23437823

ABSTRACT

Congenital melanocytic nevi (CMN) are pigmented lesions presenting on the skin in approximately 1% of all newborns at or shortly after birth. CMN have been described as being associated with several anomalies, including cranial bone hypertrophy, scoliosis, and spina bifida. This is the first report to describe a giant congenital melanocytic nevus on the scalp associated with cranial involvement, poliosis, and alopecia.


Subject(s)
Alopecia/complications , Hair Diseases/complications , Nevus, Pigmented/complications , Skin Neoplasms/complications , Skull/pathology , Humans , Male , Nevus, Pigmented/congenital , Nevus, Pigmented/pathology , Scalp/pathology , Skin Neoplasms/congenital , Skin Neoplasms/pathology , Young Adult
5.
J Endocrinol ; 211(3): 285-95, 2011 Dec.
Article in English | MEDLINE | ID: mdl-21965547

ABSTRACT

Cortisol concentration in both serum and saliva sharply increases and reaches a peak within the first hour after waking in the morning. This phenomenon is known as the cortisol awakening response (CAR) and is used as an index of hypothalamus-pituitary-adrenal (HPA) axis function. We examined whether ovarian steroid concentrations increased after awakening as with the CAR in the HPA axis. To do this, cortisol, estradiol-17ß (E(2)), and progesterone (P(4)) concentrations were determined in saliva samples collected immediately upon awakening and 30 and 60 min after awakening in women with regular menstrual cycles and postmenopausal women. We found that both E(2) and P(4) concentrations increased during the post-awakening period in women with regular menstrual cycles, but these phenomena were not seen in any postmenopausal women. The area under the E(2) and P(4) curve from the time interval immediately after awakening to 60 min after awakening (i.e. E(2)auc and P(4)auc) in women with regular menstrual cycles were greater than those in the postmenopausal women. E(2) and P(4) secretory activity during the post-awakening period was influenced by the phase of the menstrual cycle. E(2)auc in the peri-ovulatory phase and P(4)auc in the early to mid-luteal phase were greater than in the menstrual phase. Meanwhile, cortisol secretory activity during the post-awakening period was not influenced by menstrual status or the phase of menstrual cycle. These findings indicate that, as with the CAR in the HPA axis function, ovarian steroidogenic activity increased after awakening and is closely associated with menstrual status and phase of menstrual cycle.


Subject(s)
Estradiol/metabolism , Hydrocortisone/metabolism , Progesterone/metabolism , Wakefulness/physiology , Adult , Circadian Rhythm/physiology , Female , Humans , Menstrual Cycle/physiology , Middle Aged , Postmenopause/physiology , Saliva/metabolism , Young Adult
6.
J Biomed Opt ; 16(8): 087013, 2011 Aug.
Article in English | MEDLINE | ID: mdl-21895340

ABSTRACT

The aim is to study cerebral vascular functional connectivity during motor tasks and resting state using multichannel frequency-domain near-infrared spectrophotometry. Maps of 5.7 × 10.8 cm size displaying changes in cerebral oxyhemoglobin (O(2)Hb), deoxyhemoglobin (HHb), and total hemoglobin (tHb) concentrations were measured in the motor cortex in 12 subjects (mean age of 28.8±12.7 yrs) during resting state and during two palm squeezing tasks with different timing. For each condition, phase plane plots, cross correlation functions, and connectivity indices were generated for O(2)Hb, HHb, and tHb. The amplitude of the concentration changes in O(2)Hb and HHb depends on the age of the subject. We found large regions of connectivity, which were similar for resting state and task conditions. This means the spatial relationships during resting state, when changes in O(2)Hb, HHb, and tHb corresponded to spontaneous oscillations, were correlated to the spatial patterns during the activation tasks, when changes in O(2)Hb, HHb, and tHb concentration were related to the alternation of stimulation and rest. Thus, the vascular functional connectivity was also present during resting state. The findings suggest that the vascular response to functional activation may be a nonlinear synchronization phenomenon and that resting state processes are more important than previously expected.


Subject(s)
Brain Mapping/methods , Hemoglobins/analysis , Motor Activity/physiology , Rest/physiology , Spectroscopy, Near-Infrared/methods , Adolescent , Adult , Cortical Synchronization/physiology , Female , Hemoglobins/metabolism , Humans , Male , Middle Aged , Motor Cortex/metabolism , Nonlinear Dynamics , Task Performance and Analysis
7.
J Dermatol ; 37(11): 965-72, 2010 Nov.
Article in English | MEDLINE | ID: mdl-21039785

ABSTRACT

The incidence of infections caused by non-tuberculous mycobacteria has increased in recent years, due to a rise in dermatological procedures and a greater prevalence of immunosuppression in the general population. This study investigated the clinical and microbiological findings of non-tuberculous mycobacterial skin infections. The study population included 29 patients from whom non-tuberculous mycobacteria were cultured after isolation from skin biopsy materials, cutaneous abscesses or exudates. Clinical, microbiological and epidemiological data were collected from each patient. Eight patients were immunocompromised while 21 were not. Precipitating factors such as acupuncture, filler injection, surgical procedures and other traumatic events preceded infection in 13 (including 11 normal hosts and two immunocompromised hosts) of the 29 patients. Multiple skin lesions were present in eight patients (including three normal hosts and five immunocompromised hosts). In eight patients (including four immunocompromised hosts), symptoms were accompanied by tenosynovitis, osteomyelitis and myositis. Mycobacterium abscessus was isolated from nine patients, Mycobacterium fortuitum was isolated from nine patients, Mycobacterium chelonae was isolated from six patients, Mycobacterium marinum was isolated from two patients, a Mycobacterium avium complex member was isolated from two patients, and Mycobacterium haemophilum was isolated from one patient. Ten of the 24 cases caused by rapidly growing organisms (i.e. M. chelonae, M. abscessus and M. fortuitum groups) were precipitated by skin injuries such as acupuncture, filler infection and other medical procedures. Increases in skin medical procedures, including both acupuncture and esthetic interventions, explain the increasing incidence of these organisms. Immunocompromised patients tended to develop multiple skin lesions and deep tissue infections.


Subject(s)
Mycobacterium Infections/microbiology , Mycobacterium/isolation & purification , Skin Diseases, Bacterial/microbiology , Adolescent , Adult , Aged , Child , Female , Humans , Immunocompromised Host , Male , Middle Aged , Mycobacterium Infections/epidemiology , Mycobacterium Infections, Nontuberculous/epidemiology , Mycobacterium Infections, Nontuberculous/microbiology , Retrospective Studies , Skin/injuries , Skin Diseases, Bacterial/epidemiology , Young Adult
8.
J Vasc Interv Radiol ; 18(9): 1094-101, 2007 Sep.
Article in English | MEDLINE | ID: mdl-17804770

ABSTRACT

PURPOSE: Measurements in muscle tissue are often performed at a selected single location over the muscle of interest. The hypothesis is that the values obtained reflect the status within the entire muscle or muscle group. This, however, may not be the case. The study was performed to investigate whether this hypothesis is true for hemodynamics and oxygenation in the healthy human calf muscle at rest. MATERIALS AND METHODS: Hemoglobin flow, blood flow, oxygen consumption, and venous hemoglobin oxygen saturation were mapped at 22 locations in 30 legs of 15 healthy subjects (nine women, six men aged 26-37 years) simultaneously by using frequency-domain near-infrared spectrophotometry with a specially designed probe during venous occlusion. RESULTS: For all parameters, spatial heterogeneity was found between subjects and within individual legs. All parameters were highly significantly different when comparing proximal and distal regions. Differences were also found between medial and lateral regions. The global mean values (+/-standard deviation) over all measurements were as follows: hemoglobin flow, 1.27 micromol per 100 mL/min +/- 0.88; blood flow, 0.56 mL per 100 g/min +/- 0.38; oxygen consumption, 0.016 mL per 100 g/min +/- 0.011; and venous oxygen saturation, 77.6% +/- 5.9. The thickness of the overlying adipose tissue had an influence on the measurements and must be considered. CONCLUSION: Highly significant spatial heterogeneity of hemodynamics and oxygenation was found in the healthy human calf muscle.


Subject(s)
Blood Flow Velocity/physiology , Muscle, Skeletal/blood supply , Muscle, Skeletal/physiology , Oxygen/metabolism , Spectrophotometry, Infrared/methods , Adult , Female , Humans , Male , Metabolic Clearance Rate , Thigh/blood supply , Thigh/physiology , Tissue Distribution
9.
Arch Gerontol Geriatr ; 39(3): 207-25, 2004.
Article in English | MEDLINE | ID: mdl-15381340

ABSTRACT

Cerebral hemodynamic responses due to normal aging may interfere with hormonal changes, drug therapy, diseases, life style, and other factors. Age-correlated alterations in cerebral vasculature and autoregulatory mechanisms are the subject of interest in many studies. Near-infrared spectroscopy (NIRS) is widely used for monitoring cerebral hemodynamics and oxygenation changes at the level of small vessels. We believe that the compensatory ability of cerebral arterioles under hypoxic conditions and the dilatatory ability of cerebral vessels due to vasomotion may decline with normal aging. To test this hypothesis we used frequency-domain NIRS to measure changes in cerebral tissue oxygenation and oxy- and deoxy-hemoglobin concentrations caused by hypoxia during breath holding. We also assessed cerebral vasomotion during profound relaxation. Thirty seven healthy volunteers, 12 females and 25 males, ranging from 22 to 56 years of age (mean age 35 +/- 11 years) participated in the study. We observed age-correlated changes in the cerebral hemodynamics of normal subjects: diminished cerebral hemodynamic response to hypoxia due to breath holding in middle-aged subjects (38-56 years) and reduced amplitude of cerebral hemodynamic changes due to vasomotion during rest. Snoring related changes in cerebral hemodynamics did not allow us to observe the effect of age in a group of snorers. The prolonged supine position influenced measured changes due to hypoxia. In this investigation NIRS methodology allowed detection of age-correlated changes in cerebral oxygenation and hemodynamics. Other variables, such as snoring or posture impacted the observations in our group of healthy volunteers.


Subject(s)
Aging/physiology , Cerebrovascular Circulation/physiology , Hemodynamics/physiology , Spectroscopy, Near-Infrared/methods , Adult , Age Factors , Female , Heart Rate/physiology , Humans , Male , Middle Aged , Oxygen/blood , Oxyhemoglobins/analysis , Spectroscopy, Near-Infrared/instrumentation
10.
Psychophysiology ; 40(4): 521-8, 2003 Jul.
Article in English | MEDLINE | ID: mdl-14570160

ABSTRACT

Brain activity is associated with physiological changes, which alter the optical properties of the tissue in the near-infrared part of the spectrum. Two major types of optical signals following functional brain activation can be distinguished: a slow signal due to hemodynamic changes and a fast signal, which is directly related to neuronal activity. The fast signal is small and therefore difficult to detect. We used a specially noise-optimized frequency-domain near-infrared spectrometer with a pi-sensor, which was expected to be particularly sensitive to deeper tissue layers, to investigate the human visual cortex during visual stimulation generated by a checkerboard. We were able to detect significant fast signals in single light bundles, but not in pi-signals. The fast signals were mostly collocated with strong slow hemodynamic signals, but showed a higher degree of localization than the latter. The latencies of 40 +/- 16 ms of the fast signals were similar between locations. Our results also indicate that the brain responds differently to a single and double (forth and back) reversal of the checkerboard, with a stronger reaction upon the double reversal.


Subject(s)
Spectroscopy, Near-Infrared/methods , Visual Cortex/physiology , Adult , Algorithms , Female , Humans , Image Processing, Computer-Assisted , Male , Photic Stimulation , Visual Cortex/anatomy & histology
12.
Neuroimage ; 19(4): 1521-31, 2003 Aug.
Article in English | MEDLINE | ID: mdl-12948708

ABSTRACT

To study the behavior of cerebral physiological parameters and to further the understanding of the functional magnetic resonance imaging (fMRI) blood-oxygen-level-dependent (BOLD) effect, multisource frequency-domain near-infrared and BOLD fMRI signals were recorded simultaneously during motor functional activation in humans. From the near-infrared data information was obtained on the changes in cerebral blood volume and oxygenation. To relate our observations to changes in cerebral blood flow the well-known "balloon" model was employed. Our data showed that the deoxyhemoglobin concentration is the major factor determining the time course of the BOLD signal. The increase in cerebral blood oxygenation during functional activation is due to an increase in the velocity of blood flow, and occurs without significant swelling of the blood vessels.


Subject(s)
Blood Volume/physiology , Hemoglobins/metabolism , Image Processing, Computer-Assisted/methods , Magnetic Resonance Imaging/methods , Motor Cortex/blood supply , Oxygen Consumption/physiology , Psychomotor Performance/physiology , Adolescent , Adult , Arousal/physiology , Attention/physiology , Humans , Male , Mathematical Computing , Middle Aged , Motor Cortex/physiology , Oxyhemoglobins/metabolism , Regional Blood Flow/physiology , Spectroscopy, Near-Infrared
13.
J Vasc Surg ; 37(5): 1017-26, 2003 May.
Article in English | MEDLINE | ID: mdl-12756348

ABSTRACT

PURPOSE: Near-infrared spectrophotometry is used to measure flow, concentration, and oxygenation of hemoglobin in arterioles, capillaries, and venules several centimeters deep in tissue. The purpose of this study was to investigate the distribution of flow, concentration, and oxygenation of hemoglobin in calf muscle in patients with documented peripheral arterial occlusive disease (PVD), patients with risk factors for PVD,and healthy younger subjects at rest. METHOD: With a frequency-domain near-infrared spectrophotometer and a specially designed probe, we generated maps at 22 locations simultaneously of hemoglobin flow, concentration, and oxygenation, with the venous occlusion method. Eight legs of 7 patients with diagnosed PVD (PVD group), 10 legs of 8 patients with normal ankle-brachial index but with risk factors for PVD (RF group), and 16 legs of 8 healthy subjects (H group) were studied. RESULTS: Global mean values were significantly (P <.05) different between the three groups for oxygen consumption (PVD group, 0.027 +/- 0.009 mL/100 g/min; RF group, 0.038 +/- 0.017 mL/100 g/min; H group, 0.022 +/- 0.020 mL/100 g/min), venous oxygen saturation (PVD, 59.7% +/- 15.4%; RF, 69.6% +/- 10.5%; H, 80.8% +/- 4.5%), and, at 60 s of venous occlusion, concentration changes in oxyhemoglobin (PVD, 4.48 +/- 3.25 micromol/L; RF, 8.44 +/- 2.33 micromol/L; H, 6.85 +/- 4.57 micromol/L), deoxyhemoglobin (PVD, 3.60 +/- 0.73 micromol/L; RF, 4.39 +/- 1.30 micromol/L; H, 2.36 +/- 1.79 micromol/L), and total hemoglobin (PVD, 8.07 +/- 3.83 micromol/L; RF, 12.83 +/- 2.75 micromol/L; H, 9.21 +/- 6.34 micromol/L). No significant difference was found between the three groups for hemoglobin flow (PVD, 0.92 +/- 0.69 micromol/100 mL/min; RF, 1.68 +/- 0.50 micromol/100 mL/min; H, 1.44 +/- 1.17 micromol/100 mL/min) and blood flow (PVD, 0.45 +/- 0.28 mL/100 g/min; RF, 0.77 +/- 0.21 mL/100 g/min; H, 0.62 +/- 0.50 mL/100 g/min). All parameters featured a distribution dependent on location. CONCLUSION: Mean value for venous oxygen saturation was higher in healthy subjects compared to patients with documented PVD. In patients with PVD, areas of lower oxygenation were clearly discernible. At distal locations of calf muscle, significant correlations between reduced hemoglobin flow, venous oxygen saturation, oxyhemoglobin, and total hemoglobin and reduced ankle-brachial index were found. Maps revealed localized irregularities in oxyhemoglobin, total hemoglobin, and venous oxygen saturation in patients with PVD. Near-infrared spectrophotometry is a noninvasive bedside technique that can enable determination of blood flow and oxygenation in tissue and may provide a method for evaluating patients with PVD.


Subject(s)
Hemoglobins/metabolism , Muscles/metabolism , Oxygen/blood , Peripheral Vascular Diseases/blood , Peripheral Vascular Diseases/diagnosis , Adult , Aged , Ankle/blood supply , Ankle/physiology , Arm/blood supply , Arm/physiology , Biomarkers/blood , Blood Pressure/physiology , Brachial Artery/physiology , Female , Humans , Male , Middle Aged , Muscles/physiopathology , Observer Variation , Oxygen Consumption/physiology , Peripheral Vascular Diseases/physiopathology , Regional Blood Flow/physiology , Risk Factors , Spectrophotometry, Infrared , Statistics as Topic , Tibial Arteries/physiology
14.
Adv Exp Med Biol ; 510: 193-7, 2003.
Article in English | MEDLINE | ID: mdl-12580427

ABSTRACT

Using non-invasive near infrared spectroscopy fast changes in the range of ms in the optical properties of neurons during brain activity have been described. Since the signal is small, the system to detect it has to be highly noise optimized. We used a frequency-domain tissue oximeter, whose laser diodes were modulated at 110 MHz and the amplitude (AC), mean intensity (DC) and phase (phi) of the modulated optical signal was measured at 96 Hz sample rate. In two volunteers, 36 and 37 years old, the probe consisting of 4 crossed source detector pairs was placed above the motor cortex (C3 position), contralateral to the hand performing the tapping exercise. The tapping frequency was set at 2.5 times the heart rate of the subject to avoid the influence of harmonics on the signal. An electronic device recorded the tapping movement. Control-data were obtained from a solid medium of approximately the same optical properties as the human head. To reduce physiological noise the arterial pulsatility was removed using an adaptive filter, the data was detrended by a high pass filter and a cross correlation function between the optical data and the tapping signal was calculated. The instrumental noise of the control data was very low (AC mean 0.0015% +/- SD 0.00092%, DC 0.00037% +/- 0.00023% and phi 0.00083 degrees +/- 0.00042 degrees). On the head the noise level was AC 0.0042% +/- 0.0031%, DC 0.0021% +/- 0.0012% and phi 0.0020 degrees +/- 0.0017 degrees. In 14 DC, 5 AC and 0 phi out of 30 locations a fast signal was detected, which was higher (p<0.001) than the noise level. This signal disappeared during non-tapping periods. With the signal to noise ratio that we have achieved single subject measurements become feasible.


Subject(s)
Motor Cortex/physiology , Neurons/physiology , Animals , Hemodynamics/physiology , Motor Cortex/blood supply , Oximetry/instrumentation , Oximetry/methods , Reproducibility of Results , Signal Transduction/physiology , Spectrophotometry, Infrared/methods
15.
Adv Exp Med Biol ; 510: 225-30, 2003.
Article in English | MEDLINE | ID: mdl-12580432

ABSTRACT

We investigated the influence of the adipose tissue thickness (ATT) on near-infrared spectroscopy (NIRS) measurements of the absorption coefficient (mu a), the reduced scattering coefficient (mu s') and changes in concentrations of oxyhemoglobin ([O2Hb]) and deoxyhemoglobin ([HHb]). We used a frequency domain spectrometer and a special probe to generate maps of these parameters on the human calf during venous occlusion. For ATT below 6 mm mu a remained constant, whereas for ATT between 6 and 14 mm mu a decreased quickly and became almost constant again for ATT larger than 14 mm. Mu s' was not significantly altered by the ATT but the values showed a high variability between subjects. We found significantly different changes in both the [O2Hb] and the [HHb] between the proximal and distal locations of measurement. Although ATT influences the recovery of the optical properties of the underlying tissue, these differences depending on the location cannot be sufficiently explained by the ATT for the following reasons. The ATT varied little within one subject (mean difference 0.88 +/- 1.80 mm). The inter-subject variability was 5 times higher. For a given ATT within one subject we observed different values for changes in [O2Hb] and [HHb] depending on the measurement location. Moreover for a smaller ATT the difference between the values of delta[O2Hb] and delta[HHb] proximal versus distal were more distinct. The thinner the overlying tissue (ATT) the higher is the proportion of muscle tissue in the probed tissue volume. Therefore these differences are most likely coming from the muscle tissue rather than the ATT. This indicates that although the ATT has an evident influence on the measurement of optical parameters and hemodynamics and should therefore be recognized when performing NIRS measurements, other factors will have to be considered as well.


Subject(s)
Adipose Tissue/anatomy & histology , Hemodynamics , Oxygen Consumption/physiology , Oxyhemoglobins/metabolism , Hemoglobins/metabolism , Humans , Oximetry/methods , Reproducibility of Results , Spectrophotometry, Infrared/methods
16.
Neuroimage ; 17(4): 1868-75, 2002 Dec.
Article in English | MEDLINE | ID: mdl-12498761

ABSTRACT

Millisecond changes in the optical properties of the human brain during stimulation were detected in five volunteers using noninvasive frequency-domain near-infrared spectroscopy. During a motor stimulation task we found highly significant signals, which were directly related to neuronal activity and exhibited much more localized patterns than the slow hemodynamic signals that are also detected by the near-infrared method. We considerably reduced the noise in the instrumental system and improved data analysis algorithms. With the achieved signal-to-noise ratio, single subject measurements were feasible without the requirement of particularly strong stimuli and within a reasonable period of measurement of 5 min at a mean signal-to-noise ratio of 3.6. The advantage of this noninvasive technique with respect to electrical recording is that it is able to detect neuronal activity with the relatively high spatial resolution of 8 mm.


Subject(s)
Motor Cortex/physiology , Oxygen Consumption/physiology , Spectroscopy, Near-Infrared/methods , Synaptic Transmission/physiology , Dominance, Cerebral/physiology , Feasibility Studies , Female , Hemoglobins/metabolism , Humans , Male , Motor Activity/physiology , Motor Cortex/blood supply , Oxyhemoglobins/metabolism , Reference Values , Regional Blood Flow/physiology , Sensitivity and Specificity
SELECTION OF CITATIONS
SEARCH DETAIL
...