We have applied functional near-infrared spectroscopy(fNIRS)to the human forehead to distinguish different levels of mental workload on the basis of hemodynamic changes occurring in the prefrontal cortex.We report dat...We have applied functional near-infrared spectroscopy(fNIRS)to the human forehead to distinguish different levels of mental workload on the basis of hemodynamic changes occurring in the prefrontal cortex.We report data on 3 subjects from a protocol involving 3 mental workload levels based on to working memory tasks.To quantify the potential of fNIRS for mental workload discrimination,we have applied a 3-nearest neighbor classification algorithm based on the amplitude of oxyhemoglobin(HbO2)and deoxyhemoglobin(HbR)concentration changes associated with the working memory tasks.We have found classification success rates in the range of 44%-72%,which are significantly higher than the corresponding chance level(for random data)of 19.1%.This work shows the potential of fNIRS for mental workload classification,especially when more parameters(rather than just the amplitude of concentration changes used here)and more sophisticated classification algorithms(rather than the simple 3-nearest neighbor algorithm used here)are considered and optimized for this application.展开更多
The present work describes the use of noninvasive diffuse optical tomography(DOT)technology to measure hemodynamic changes,providing relevant information which helps to understand the basis of neurophysiology in the h...The present work describes the use of noninvasive diffuse optical tomography(DOT)technology to measure hemodynamic changes,providing relevant information which helps to understand the basis of neurophysiology in the human brain.Advantages such as portability,direct measurements of hemoglobin state,temporal resolution,non-restricted movements as occurs in magnetic resonance imaging(MRI)devices mean that DOT technology can be used in research and clinical fields.In this review we covered the neurophysiology,physical principles underlying optical imaging during tissue-light interactions,and technology commonly used during the construction of a DOT device including the source-detector requirements to improve the image quality.DOT provides 3 D cerebral activation images due to complex mathematical models which describe the light propagation inside the tissue head.Moreover,we describe briefly the use of Bayesian methods for raw DOT data filtering as an alternative to linear filters widely used in signal processing,avoiding common problems such as the filter selection or a false interpretation of the results which is sometimes due to the interference of background physiological noise with neural activity.展开更多
Treatment-induced apoptosis of cancer cells is one goal of cancer therapy.Interestingly,more heat is generated by mitochondria during apoptosis,especially the uncoupled apoptotic state,^(1,2) compared to the resting s...Treatment-induced apoptosis of cancer cells is one goal of cancer therapy.Interestingly,more heat is generated by mitochondria during apoptosis,especially the uncoupled apoptotic state,^(1,2) compared to the resting state.In this case study,we explore these thermal effects by longitudinally measuring temperature variations in a breast lesion of a pathological complete responder during neoadjuvant chemotherapy(NAC).Diffuse Optical Spectroscopic Imaging(DOSI)was employed to derive absolute deep tissue temperature using subtle spectral features of the water peak at 975 nm.^(3)A significant temperature increase was observed in time windows during the anthracycline and cyclophosphamide(AC)regimen but not in the paclitaxel and bevacizumab regimen.Hemoglobin concentration changes generally did not follow temperature,suggesting the measured temperature increases were likely due to mitochondrial uncoupling rather than a direct vascular effect.A simultaneous increase of tissue oxygen saturation with temperature was observed,suggesting that oxidative stress also contributes to apoptosis.Although preliminary,this study indicates longitudinal DOSI tissue temperature monitoring provides information that can improve our understanding of the mechanisms of tissue response during NAC.展开更多
基金supported by NSF Award IIS-0713506,and NIH Grant DA021817。
文摘We have applied functional near-infrared spectroscopy(fNIRS)to the human forehead to distinguish different levels of mental workload on the basis of hemodynamic changes occurring in the prefrontal cortex.We report data on 3 subjects from a protocol involving 3 mental workload levels based on to working memory tasks.To quantify the potential of fNIRS for mental workload discrimination,we have applied a 3-nearest neighbor classification algorithm based on the amplitude of oxyhemoglobin(HbO2)and deoxyhemoglobin(HbR)concentration changes associated with the working memory tasks.We have found classification success rates in the range of 44%-72%,which are significantly higher than the corresponding chance level(for random data)of 19.1%.This work shows the potential of fNIRS for mental workload classification,especially when more parameters(rather than just the amplitude of concentration changes used here)and more sophisticated classification algorithms(rather than the simple 3-nearest neighbor algorithm used here)are considered and optimized for this application.
文摘The present work describes the use of noninvasive diffuse optical tomography(DOT)technology to measure hemodynamic changes,providing relevant information which helps to understand the basis of neurophysiology in the human brain.Advantages such as portability,direct measurements of hemoglobin state,temporal resolution,non-restricted movements as occurs in magnetic resonance imaging(MRI)devices mean that DOT technology can be used in research and clinical fields.In this review we covered the neurophysiology,physical principles underlying optical imaging during tissue-light interactions,and technology commonly used during the construction of a DOT device including the source-detector requirements to improve the image quality.DOT provides 3 D cerebral activation images due to complex mathematical models which describe the light propagation inside the tissue head.Moreover,we describe briefly the use of Bayesian methods for raw DOT data filtering as an alternative to linear filters widely used in signal processing,avoiding common problems such as the filter selection or a false interpretation of the results which is sometimes due to the interference of background physiological noise with neural activity.
基金This work was supported by NIH R01-CA75124,R01-EB002109Susan G.Komen for the Cure Postdoctoral Fellowship provided to University of Pennsylvania,and P41-RR01192,U54-CA105480,U54CA136400,P30-CA62203 provided to University of California,Irvine.
文摘Treatment-induced apoptosis of cancer cells is one goal of cancer therapy.Interestingly,more heat is generated by mitochondria during apoptosis,especially the uncoupled apoptotic state,^(1,2) compared to the resting state.In this case study,we explore these thermal effects by longitudinally measuring temperature variations in a breast lesion of a pathological complete responder during neoadjuvant chemotherapy(NAC).Diffuse Optical Spectroscopic Imaging(DOSI)was employed to derive absolute deep tissue temperature using subtle spectral features of the water peak at 975 nm.^(3)A significant temperature increase was observed in time windows during the anthracycline and cyclophosphamide(AC)regimen but not in the paclitaxel and bevacizumab regimen.Hemoglobin concentration changes generally did not follow temperature,suggesting the measured temperature increases were likely due to mitochondrial uncoupling rather than a direct vascular effect.A simultaneous increase of tissue oxygen saturation with temperature was observed,suggesting that oxidative stress also contributes to apoptosis.Although preliminary,this study indicates longitudinal DOSI tissue temperature monitoring provides information that can improve our understanding of the mechanisms of tissue response during NAC.
