Experimentally Measured Optical Pathlengths for the Adult Head, Calf and Forearm and the Head of the Newborn Infant as a Function of Inter Optode Spacing

Zee, Pieter van der; Cope, M; Arridge, Simon; Essenpreis, Matthias; Potter, Laurence; Edwards, Anthony; Wyatt, John; McCormick, David; Roth, Simon; Reynolds, E. O. R.; Delpy, David T.

doi:10.1007/978-1-4615-3404-4_17

Cited by 392 publications

(194 citation statements)

References 24 publications

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“…The emitter and detector were encased in a rubber holder with a separation distance of 4 cm. A differential path length factor of 5.93 for the adult forehead was used (van der Zee et al, 1992) to provide a measure of concentration changes (Δ) in micromolar (μM) units of O 2 Hb, HHb, and tHb (sample rate: 2 Hz). The probes were placed approximately over the left and right dorsolateral PFC (between Fp1-F3 and Fp2-F4, respectively, of the International 10-20 System for EEG electrode placement) and were secured to the skin using a double adhesive sticker.…”

Section: Methodsmentioning

confidence: 99%

Self-reported tolerance influences prefrontal cortex hemodynamics and affective responses

Tempest

Parfitt

2015

Cogn Affect Behav Neurosci

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The relationship between cognitive and sensory processes in the brain contributes to the regulation of affective responses (pleasure-displeasure). Exercise can be used to manipulate sensory processes (by increasing physiological demand) in order to examine the role of dispositional traits that may influence an individual's ability to cognitively regulate these responses. With the use of near infrared spectroscopy, in this study we examined the influence of self-reported tolerance upon prefrontal cortex (PFC) hemodynamics and affective responses. The hemodynamic response was measured in individuals with high or low tolerance during an incremental exercise test. Sensory manipulation was standardized against metabolic processes (ventilatory threshold [VT] and respiratory compensation point [RCP]), and affective responses were recorded. The results showed that the high-tolerance group displayed a larger hemodynamic response within the right PFC above VT (which increased above RCP). The lowtolerance group showed a larger hemodynamic response within the left PFC above VT. The high-tolerance group reported a more positive/less negative affective response above VT. These findings provide direct neurophysiological evidence of differential hemodynamic responses within the PFC that are associated with tolerance in the presence of increased physiological demands. This study supports the role of dispositional traits and previous theorizing into the underlying mechanisms (cognitive vs. sensory processes) of affective responses.

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Section: Methodsmentioning

confidence: 99%

Self-reported tolerance influences prefrontal cortex hemodynamics and affective responses

Tempest

Parfitt

2015

Cogn Affect Behav Neurosci

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“…As the source-detector distance increases the average path length increases significantly while the average photon visit depth increases only slightly. Maximum penetration depth of light is thought to be approximately half the distance between source and detector [21,22]. Studies have been widely performed to analyze optical propagation in various media.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Diffuse Reflectance in Multi-layered Tissue for High Intensity Laser Therapy

Lee¹,

Youn²

2013

Journal of the Optical Society of Korea

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Pain is one of the quite common symptoms in clinics and many treatment methods have been applied to relieve pain. Among the treatments, high-intensity light therapy for pain has been introduced, but this therapy has not been fully supported by confirmed efficacy due to the absence of quantitative assessments and treatment feedback data in real time. In this study, the evaluation of light distribution in tissue was performed with current high-intensity light sources quantitatively using light-tissue interaction simulations. The diffuse reflectance in tissue was generated using Monte Carlo simulation that traces photons as they undergo multiple scattering and absorption within each tissue layer (skin, fat, and muscle) and within multi-layered tissue. The results showed that the highest diffuse reflectance and the deepest penetration of tissue were achieved at λ =830 nm when compared with other wavelengths like λ =650 nm, 980 nm and 1064 nm.

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“…An emitter-detector separation distance of 4 cm was adopted in this study in order to maximize light penetration depth in tissue [4]. A DPF of 3.59 for the forearm has been employed [9]. …”

Section: B Ppg Processing System (Zen Ppg)mentioning

confidence: 99%

Investigation of photoplethysmography and Near Infrared Spectroscopy for the assessment of tissue blood perfusion

Abay

Kyriacou

2014

2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society

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Experimentally Measured Optical Pathlengths for the Adult Head, Calf and Forearm and the Head of the Newborn Infant as a Function of Inter Optode Spacing

Cited by 392 publications

References 24 publications

Self-reported tolerance influences prefrontal cortex hemodynamics and affective responses

Self-reported tolerance influences prefrontal cortex hemodynamics and affective responses

Evaluation of Diffuse Reflectance in Multi-layered Tissue for High Intensity Laser Therapy

Investigation of photoplethysmography and Near Infrared Spectroscopy for the assessment of tissue blood perfusion

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