Imagent™ provides a balance between temporal and spatial resolution for the cognitive study of superficially located areas of human brain by addressing two main applications techniques:

1. Functional Near Infrared Spectroscopy (fNIRS), which detects changes in the absorption of the optical signal in response to a stimulus and provides a map of the areas where the changes occur. The changes in the optical signal (time scale > 100 ms), are due to local variations of oxy- and deoxy-hemoglobin concentrations.
    
2. Event Related Optical Signal (EROS), which detects changes in the scattered component of the diffuse signal subsequent to a stimulus. The changes (time scale < 100 ms) are due to the variation in the shape of the glia and neurons and/or in the optical properties of the membrane.

Brain imaging techniques can be broadly classified in two groups. One group includes the techniques that have a good spatial resolution (up to 1-2 millimeters) but a poor temporal resolution, such as functional Magnetic Resonance Imaging (fMRI) and Positron Emission Tomography (PET). The second group includes techniques featuring an excellent temporal resolution (of the order of milliseconds) but providing a limited spatial information. This group includes the Event Related Brain Potential (ERP) and the Magneto-encephalography (MEG). Imagent™ captures both the slow signals (hemodynamic changes) and the fast signals (EROS).

Notice: Investigational device. Limited by Federal (or United States) law to investigational use. The ISS Imagent™ is presently used for research only.

How Imagent™ Works

Imagent’s working principle is based on the use of near infrared light for probing the cortical surface. The main tissue absorbers in the wavelength region spanning from 700 nm to 900 nm are oxy-hemoglobin (HbO₂) and deoxy-hemoglobin (Hb); on a smaller scale, water, fat and cytochrome oxidase contribute to the partial absorption of the light. The penetration depth of light in tissues is quite significant in this wavelength range. For typical head tissue (skin/scalp, skull and cortical layer), with an absorption coefficient of μ_a = 0.1 cm^-1 and a scattering coefficient μ_s' = 8 cm^-1, the maximum optical penetration can be estimated to be about 1.5 cm when a detector is placed at 4 cm from the source. The penetration depth can be increased by increasing the distance between the source and the detector, although, eventually, the signal-to-noise ratio of the measurement deteriorates.

Figure 1. Main tissue absorbers in the 600-1100 nm region.

Imagent™ utilizes laser diodes emitting at 690 nm and 830 nm. The light is delivered by fiber optics positioned on the head. Upon entering the tissue, the near infrared light, albeit weakly absorbed, is highly scattered by the tissue inhomogeneities. A fraction of the light leaves the tissue and it is collected by the collecting fiber that carries it back to the light detectors housed in the unit for data processing. The fibers are kept in place by a headgear, which is available for adults and children; for the study of specific areas, pads sensors are available. Up to 128 fibers and up to 60 detectors bundles (for a total of 3840 optical channels) can be positioned on the head of an adult. Different patterns (montages) of the excitation and collection fibers can be used.

Figure 2. Light penetration in brain tissue using Imagent™

Imagent™ utilizes the frequency domain technology whereas the light sources are modulated at high frequency (of the order of 100 MHz) and three parameters of the detected signal are measured: the intensity, the modulation depth and the time it takes to traverse the tissue (phase delay). Any two combinations of the three measured quantities can be utilized to provide changes in the physiological parameters, the choice being dictated by the specific parameter to be measured, by the need to reduce physiological noise and by the time scale of the event to be measured.

Applications of Imagent™

fNIRS

Cognitive Neuroscience

• Auditory cortex
• Motor cortex
• Visual cortex
• Language centers

Physiological monitoring

• Stress studies
• Working memory in aging
• Mapping epileptic areas in the brain

Virtual Reality

Brain Computer Interface

EROS

Cognitive Neuroscience

• Auditory cortex
• Motor cortex
• Visual cortex
• Language centers

Resources

Videos

Click on a picture to view the video.

Learn Piano with BACh: An Adaptive Learning Interface that Adjusts Task Difficulty based on Brain State
(courtesy of Dr. Beste Filiz Yuksel, Tufts University, Medford, MA)

Monitoring Attentional State and Stress Management (Mind-Reading Research)
The study investigates mental overload in pilots
(courtesy of fNIRS Cognitive State Monitoring Lab/NASA, Glenn Research Center, Cleveland, OH)

Using Light to measure brain activity; EROS optical Brain Imaging Demonstration
(courtesy of Beckman Institute for Advanced Science and Technology, Urbana, IL)

Technical Notes

	Imagent: Comparison with fMRI
	Imagent: the Power of the Laser Diodes
	Imagent for fNIRS and EROS Measurements

Headgear Sensors

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Sensor Pads

The sensor pads are advantageous when you only need to study area of the head, such as the motor or visual cortex. Can be used on different subject sizes.

Key Features

• Flexible foam can be strapped to multiple cranial locations
• Fiber depth can be adjusted to ensure contact
• The arrangement of emitter-detector distances are easily customizable

Key Characteristics

• Pad is made of ethylene-vinyl acetate
• Fibers are 2.5 m
• 400 µm emitter fibers with 3 mm fiber detector bundles

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Infant Pad

The infant pad is ideal for visual and motor cortex measurements and is made of comfortable ethylene-vinyl acetate (EVA) foam. The pad can be moved to multiple cranial locations and the fiber depth adjusted.

Key Features

• The arrangement of emitter-detector distances are easily customizable
• Flexible foam can be strapped to multiple cranial locations
• Fiber depth can be adjusted to ensure contact

Key Characteristics

• Pad is made of ethylene-vinyl acetate
• Fibers are 2.5 m
• 400 µm emitter fibers with 3 mm fiber detector bundles

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Universal Headgear

The Universal Headgear allows for the positioning of fibers on the whole head or just an area of interest. The signal from the sources located closer to the detector fibers probe the superficial layer; the signal detected from further distances from the detector bundle probe a deeper region. Therefore, it is possible to separate the contribution of the different layers to the signal. The headgear provides several emitter-detector distances and a variety of montages for disparate applications.

Key Features

• Low profile, very flexible, comfortable
• Many emitter-detector positions available
• Inline detector/emitter geometry maximizes overlap of sample tissue
• Allows measurements on curved surfaces

Key Characteristics

• Pad is made of ethylene-vinyl acetate
• Fibers are 2.5 m
• 400 µm emitter fibers with 3 mm fiber detector bundles

 

Fibers and Bundles

ISS has many emitter fibers and detector bundles for developing your own sensor.

The standard individual emitter fiber comes with a SMA connector on one end and bare cleaved fiber on the other end. The fiber type is 400µm-diameter core, plastic clad silica with a standard length of 2.5 meters. Other fiber lengths are available upon request. The standard fiber bundle for the collection of light and delivery to the PMT detector is a 3 mm bundle with a standard length of 2.5 m. Other fiber lengths are available upon request

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Single fiber, SMA-906 connector on one end and polished on the other end. The fiber is 400 µm in diameter and 2.5 m in length.

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Paired fibers, SMA-906 connector on one end and ferrule end tip, 75 mm -long, on the other end. Each fiber is 400 µm in diameter and 2.5 m in length.

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Flexible Detector Bundle; straight, made of individual fibers with 50µm diameter, glass. The total diameter is 3 mm DIA; length is 2.50 m.

Imagent™ Specifications

Click on a heading below to expand its contents.

fNIRS

Cognitive Neuroscience

Auditory Cortex

The Role of Visual and Auditory Temporal Processing for Chinese Children With Developmental Dyslexia
Chung, K.K., McBride-Chang, C., Wong, S.W., Cheung, H., Penney, T.B., Ho, C.S.
Ann Dyslexia., 2008, 58(1), 15-35. On the Functional Role of Temporal and Frontal Cortex Activation in Passive Detection of Auditory Deviance
Tse, C.Y., Penney, T.B.
Neuroimage., 2008, 41(4), 1462-70. Optical Imaging of Temporal Integration in Human Auditory Cortex
Sable, J.J., Low, K.A., Whalen, C.J., Maclin, E.L., Fabiani, M., Gratton, G.
Eur J Neurosci., 2007, 25(1), 298-306. Latent Inhibition Mediates N1 Attenuation to Repeating Sounds
Sable, J.J., Low, K.A., Maclin, E.L., Fabiani, M., Gratton, G.
Psychophysiology., 2004, 41(4), 636-42. Scalp-Recorded Optical Signals Make Sound Processing in the Auditory Cortex Visible
Rinne, T., Gratton, G., Fabiani, M., Cowan, N., Maclin, E., Stinard, A., Sinkkonen, J., Alho, K., Näätänen, R.
NeuroImage, 1999, 10, 620-624.

Motor Cortex

	Number-space Interactions in the Human Parietal Cortex: Enlightening the SNARC Effect With Functional Near-infrared Spectroscopy Cutini, S., Scarpa, F., Scatturin, P., Dell'Acqua, R., Zorzi, M. Cereb Cortex., 2014, 24(2), 444-51.
	Functional Near-infrared Spectroscopy-based Correlates of Prefrontal Cortical Dynamics During a Cognitive-motor Executive Adaptation Task Gentili, R.J., Shewokis, P.A., Ayaz, H., Contreras-Vidal, J.L. Front Hum Neurosci., 2013, 7, 277.
	The Cortical Control of Cycling Exercise in Stroke Patients: An fNIRS Study Lin, P.Y., Chen, J.J., Lin, S.I. Hum Brain Mapp., 2013, 34(10), 2381-90.
	Exploring the Role of Primary and Supplementary Motor Areas in Simple Motor Tasks With fNIRS Brigadoi, S., Cutini, S., Scarpa, F., Scatturin, P., Dell'Acqua, R. Cogn Process., 2012, 13 Suppl 1, S97-101.
	When in Doubt, Do It Both Ways: Brain Evidence of the Simultaneous Activation of Conflicting Motor Responses in a Spatial Stroop Task DeSoto, M.C., Fabiani, M., Geary, D.C., Gratton, G. J Cogn Neurosci., 2001, 13(4), 523-36.
	Rapid Changes of Optical Parameters in the Human Brain During a Tapping Task Gratton, G., Fabiani, M., Friedman, D., Franceschini, M.A., Fantini, S., Corballis, P., Gratton, E. J Cogn Neurosci., 1995, 7(4), 446-56.

Visual Cortex

	Early Childhood Development of Visual Texture Segregation in Full-term and Preterm Children. Sayeur, M.S., Vannasing, P., Lefrançois, M., Tremblay, E., Lepore, F., Lassonde, M., McKerral, M., Gallagher, A. Vision Res., 2015, 112, 1-10.
	Comparison of Neuronal and Hemodynamic Measures of the Brain Response to Visual Stimulation: An Optical Imaging Study. Gratton, G., Goodman-Wood, M.R., Fabiani, M. Hum Brain Mapp., 2001, 13(1), 13-25.
	Shades of Gray Matter: Noninvasive Optical Images of Human Brain Responses During Visual Stimulation. Gratton, G., Corballis, P.M., Cho, E., Fabiani, M., Hood, D.C. Psychophysiology., 1995, 32(5), 505-9.

Language Center

	Distinct Hemispheric Specializations for Native and Non-native Languages in One-day-old Newborns Identified by fNIRS Vannasing, P., Florea, O., González-Frankenberger, B., Tremblay, J., Paquette, N., Safi, D., Wallois, F., Lepore, F., Béland, R., Lassonde, M., Gallagher, A. Neuropsychologia., 2016, 84, 63-9.
	Developmental Patterns of Expressive Language Hemispheric Lateralization in Children, Adolescents and Adults Using Functional Near-infrared Spectroscopy Paquette, N., Lassonde, M., Vannasing, P., Tremblay, J., González-Frankenberger, B., Florea, O., Béland, R., Lepore, F., Gallagher, A. Neuropsychologia., 2015, 68, 117-25.
	Early Electrophysiological Markers of Atypical Language Processing in Prematurely Born Infants Paquette, N., Vannasing, P., Tremblay, J., Lefebvre, F., Roy, M.S., McKerral, M., Lepore, F., Lassonde, M., Gallagher, A. Neuropsychologia., 2015, 79(Pt A), 21-32.
	Functional Near-infrared Spectroscopy for the Assessment of Overt Reading Safi, D., Lassonde, M., Nguyen, D.K., Vannasing, P., Tremblay, J., Florea, O., Morin-Moncet, O., Lefrançois, M., Béland, R. Brain Behav., 2012, 2(6), 825-37.
	Near-infrared Spectroscopy as an Alternative to the Wada Test for Language Mapping in Children, Adults and Special Populations Gallagher, A., Thériault, M., Maclin, E., Low, K., Gratton, G., Fabiani, M., Gagnon, L., Valois, K., Rouleau, I., Sauerwein, H.C., Carmant, L., Nguyen, D.K., Lortie, A., Lepore, F., Béland, R., Lassonde, M. Epileptic Disord., 2007, 9(3), 241-55.
	Speeded Naming and Dyslexia Penney, T.B., Wong, S., Ng, K.K., McBride-Chang, C.A. Communicating Skills of Intention, 2007, 75-90.
	Morphological Structure Awareness, Vocabulary, and Reading McBride-Chang, C., Hua, S., Ng, J.Y.L., Meng, X., Penney, T.B. Vocabulary Acquisition: Implications for Reading Comprehension, 2007, 6, 104-122.
	Poor Readers of Chinese Respond Slower Than Good Readers in Phonological, Rapid Naming, and Interval Timing Tasks Penney, T.B., Leung, K.M., Chan, P.C., Meng, X., McBride-Chang, C.A. Ann Dyslexia., 2005, 55(1), 9-27.
	Brain Responses to Segmentally and Tonally Induced Semantic Violations in Cantonese Schirmer, A., Tang, S.L., Penney, T.B., Gunter, T.C., Chen, H.C. J Cogn Neurosci., 2005, 17(1), 1-12.

Physiological Monitoring

Aging Studies

	Taking the Pulse of Aging: Mapping Pulse Pressure and Elasticity in Cerebral Arteries With Optical Methods Fabiani, M., Low, K.A., Tan, C.H., Zimmerman, B., Fletcher, M.A., Schneider-Garces, N., Maclin, E.L., Chiarelli, A.M., Sutton, B.P., Gratton, G. Psychophysiology., 2014, 51(11), 1072-88.
	Multiple Electrophysiological Indices of Distinctiveness Fabiani, M. Distinctiveness and Memory, 2006, 339-360.
	Reduced Suppression or Labile Memory? Mechanisms of Inefficient Filtering of Irrelevant Information in Older Adults Fabiani, M., Low, K.A., Wee, E., Sable, J.J., Gratton, G. J Cogn Neurosci., 2006, 18(4), 637-50.
	Contributions of Cognitive Neuroscience to the Understanding of Behavior and Aging Kramer, A.F., Fabiani, M., Colcombe, S. Handbook of the Psychology of Aging, Sixth Edition, 2006, 6, 57-83.
	Electrophysiological and Optical Measures of Cognitive Aging Fabiani, M., Gratton, G. Cognitive Neuroscience of Aging: Linking Cognitive and Cerebral Aging, 2005.
	Sensory ERPs Predict Differences in Working Memory Span and Fluid Intelligence Brumback, C.R., Low, K.A., Gratton, G., Fabiani, M. Neuroreport., 2004, 15(2), 373-6.

Epilepsy Studies

	Potential Brain Language Reorganization in a Boy With Refractory Epilepsy; An fNIRS-EEG and fMRI Comparison. Vannasing, P., Cornaggia, I., Vanasse, C., Tremblay, J., Diadori, P., Perreault, S., Lassonde, M., Gallagher, A. Epilepsy Behav Case Rep., 2016, 5, 34-7.
	Recruitment of the Left Precentral Gyrus in Reading Epilepsy: A Multimodal Neuroimaging Study. Safi, D., Béland, R., Nguyen, D.K., Pouliot, P., Mohamed, I.S., Vannasing, P., Tremblay, J., Lassonde, M., Gallagher, A. Epilepsy Behav Case Rep., 2016, 5, 19-22.
	Using Patient-specific Hemodynamic Response Function in Epileptic Spike Analysis of Human Epilepsy: A Study Based on EEG-fNIRS. Peng, K., Nguyen, D.K., Vannasing, P., Tremblay, J., Lesage, F., Pouliot, P. Neuroimage., 2016, 126, 239-55.
	Hemodynamic Changes During Posterior Epilepsies: An EEG-fNIRS Study. Pouliot, P., Tran, T.P., Birca, V., Vannasing, P., Tremblay, J., Lassonde, M., Nguyen, D.K. Epilepsy Res., 2014, 108(5), 883-90.
	fNIRS-EEG Study of Focal Interictal Epileptiform Discharges. Peng, K., Nguyen, D.K., Tayah, T., Vannasing, P., Tremblay, J., Sawan, M., Lassonde, M., Lesage, F., Pouliot, P. Epilepsy Res., 2014, 108(3), 491-505.
	Noninvasive Continuous Functional Near-infrared Spectroscopy Combined With Electroencephalography Recording of Frontal Lobe Seizures. Nguyen, D.K., Tremblay, J., Pouliot, P., Vannasing, P., Florea, O., Carmant, L., Lepore, F., Sawan, M., Lesage, F., Lassonde, M. Epilepsia., 2013, 54(2), 331-40.
	Nonlinear Hemodynamic Responses in Human Epilepsy: A Multimodal Analysis With fNIRS-EEG and fMRI-EEG. Pouliot, P., Tremblay, J., Robert, M., Vannasing, P., Lepore, F., Lassonde, M., Sawan, M., Nguyen, D.K., Lesage, F. J Neurosci Methods., 2012, 204(2), 326-40.

Applications to Infants

	Perception of Caucasian and African faces in 5- to 9-month-old Caucasian infants: A functional near-infrared spectroscopy study. Timeo, S., Brigadoi, S., Farroni, T. Neuropsychologia. 2017 Sep 13. pii: S0028-3932(17)30337-8. doi: 10.1016/j.neuropsychologia.2017.09.011. [Epub ahead of print]
	Infant cortex responds to other humans from shortly after birth. Farroni, T., Chiarelli, A.M., Lloyd-Fox, S., Massaccesi, S., Merla, A., Di Gangi, V., Mattarello, T., Faraguna, D., Johnson, M.H. Sci Rep. 2013 Oct 4;3:2851. doi: 10.1038/srep02851.
	Coupled Oxygenation Oscillation Measured by NIRS and Intermittent Cerebral Activation on EEG in Premature Infants. Roche-Labarbe, N., Wallois, F., Ponchel, E., Kongolo, G., Grebe, R. Neuroimage., 2007, 36(3), 718-27.

Studies of the Brain

	Measurement of Brain Activity by Near-infrared Light Gratton, E., Toronov, V., Wolf, U., Wolf, M., Webb, A. J Biomed Opt., 2005, 10(1), 11008.
	Noninvasive Determination of the Optical Properties of Adult Brain: Near-infrared Spectroscopy Approach Choi, J., Wolf, M., Toronov, V., Wolf, U., Polzonetti, C., Hueber, D., Safonova, L.P., Gupta, R., Michalos, A., Mantulin, W., Gratton, E. J Biomed Opt., 2004, 9(1), 221-9.
	Fast Cerebral Functional Signal in the 100-ms Range Detected in the Visual Cortex by Frequency-domain Near-infrared Spectrophotometry Wolf, M., Wolf, U., Choi, J.H., Toronov, V., Paunescu, L.A., Michalos, A., Gratton, E. Psychophysiology., 2003, 40(4), 521-8.
	Absolute Frequency-domain Pulse Oximetry of the Brain: Methodology and Measurements Wolf, M., Franceschini, M.A., Paunescu, L.A., Toronov, V., Michalos, A., Wolf, U., Gratton, E., Fantini, S. Adv Exp Med Biol., 2003, 530, 61-73.
	Different Time Evolution of Oxyhemoglobin and Deoxyhemoglobin Concentration Changes in the Visual and Motor Cortices During Functional Stimulation: A Near-infrared Spectroscopy Study Wolf, M., Wolf, U., Toronov, V., Michalos, A., Paunescu, L.A., Choi, J.H., Gratton, E. Neuroimage., 2002, 16(3 Pt 1), 704-12.
	On-line Optical Imaging of the Human Brain with 160-ms Temporal Resolution ranceschini, M.A., Toronov, V., Filiaci, M., Gratton, E., Fantini, S. Opt Express, 2000, 6(3), 49-57.
	Near-infrared Study of Fluctuations in Cerebral Hemodynamics During Rest and Motor Stimulation: Temporal Analysis and Spatial Mapping Toronov, V., Franceschini, M.A., Filiaci, M., Fantini, S., Wolf, M., Michalos, A., Gratton, E. Med Phys., 2000, 27(4), 801-15.
	Cerebral Hemodynamics Measured by Near-infrared Spectroscopy at Rest and During Motor Activation Franceschini, M.A., Fantini, S., Toronov, V., Filiaci, Gratton, E. Proc. Inter-Institute Workshop on In Vivo Optical Imaging at the NIH, 1999, 73-80.
	Shades of Gray Matter: Noninvasive Optical Images of Human Brain Responses During Visual Stimulation Gratton, G., Corballis, P.M., Cho, E., Fabiani, M., Hood, D.C. Psychophysiology., 1995, 32(5), 505-9.

Monitoring Attentional State and Stress Management

	Dynamic Filtering Improves Attentional State Prediction With fNIRS Harrivel, A.R., Weissman, D.H., Noll, D.C., Huppert, T., Peltier, S.J. Biomed Opt Express., 2016, 7(3), 979-1002.
	Monitoring Attentional State With fNIRS Harrivel, A.R., Weissman, D.H., Noll, D.C., Peltier, S.J. Front Hum Neurosci., 2013, 7, 861.
	Detection of Attentional State in Long-Distance Driving Settings Using Functional Near-Infrared Spectroscopy Tucker, M., Aubert, M.C., Sampaio, V., Clamann, M., Cummings, M.L. 95th Annual Transportation Research Board Meeting, 2016.
	Investigating Mental Workload Changes in a Long Duration Supervisory Control Task Boyer, M., Cummings, M., Spence, L., Solovey, E. Interacting with Computers, 2015, 27, 512-520.

Brain Computer Interface

	Learn Piano with BACh: An Adaptive Learning Interface that Adjusts Task Difficulty based on Brain State Yuksel, B.F., Oleson, K.B., Harrison, L., Peck, E.M., Afergan, D., Chang, R., Jacob, R.J.K. CHI '16, ACM, 2016, 5372-5384.
	BRAAHMS: A Novel Adaptive Musical Interface Based on Users' Cognitive State Yuksel, B.F., Afergan, D., Peck, E.M., Griffin, G., Harrison, L., Chen, N.W.B., Chang, R., Jacob, R.J.K. NIME'15, ACM, 2015.
	A Hybrid NIRS-EEG System for Self-paced Brain Computer Interface With Online Motor Imagery Koo, B., Lee, H.G., Nam, Y., Kang, H., Koh, C.S., Shin, H.C., Choi, S. J Neurosci Methods., 2015, 244, 26-32.
	Brain-based Target Expansion Afergan, D., Shibata, T., Hincks, S.W., Peck, E.M., Yuksel, B.F., Chang, R., Jacob, R.J.K. UIST 2014, ACM, 2014, 583-593.
	Temporal Decoupling of Oxy- and Deoxy-Hemoglobin Hemodynamic Responses Detected by Functional Near-Infrared Spectroscopy (fNIRS) Tam, N.D., Zouridakis, G. Journal of Biomedical Engineering and Medical Imaging, 2014, 1(2).
	Using fNIRS Brain Sensing to Evaluate Information Visualization Interfaces Peck, E.M., Yuksel, B.F., Ottley, A., Jacob, R.J.K., Chang, R. CHI 2013, ACM, 2013, 473-482.
	Classification of Prefrontal Activity Due to Mental Arithmetic and Music Imagery Using Hidden Markov Models and Frequency Domain Near-infrared Spectroscopy Power, S.D., Falk, T.H., Chau, T. J Neural Eng., 2010, 7(2), 26002.
	Single-trial Classification of NIRS Signals During Emotional Induction Tasks: Towards a Corporeal Machine Interface Tai, K., Chau, T. J Neuroeng Rehabil., 2009, 6, 39.

Virtual Reality

An Exploratory fNIRS Study With Immersive Virtual Reality: A New Method for Technical Implementation. Seraglia, B., Gamberini, L., Priftis, K., Scatturin, P., Martinelli, M., Cutini, S. Front Hum Neurosci., 2011, 5, 176.

Technical Development

	Taking NIRS-BCIs Outside the Lab: Towards Achieving Robustness Against Environment Noise Falk, T.H., Guirgis, M., Power, S., and Chau, T.T. IEEE Trans Neural Syst Rehabil Eng., 2011, 19(2), 136-46.
	A New Method Based on ICBM152 Head Surface for Probe Placement in Multichannel fNIRS Cutini, S., Scatturin, P., Zorzi, M. Neuroimage., 2011, 54(2), 919-27.
	Bayesian Filtering of Human Brain Hemodynamic Activity Elicited by Visual Short-term Maintenance Recorded Through Functional Near-infrared Spectroscopy (fNIRS) Scarpa, F., Cutini, S., Scatturin, P., Dell'Acqua, R., Sparacino, G. Opt Express., 2010, 18(25), 26550-68.
	Validation of a Method for Coregistering Scalp Recording Locations With 3D Structural MR Image. Whalen, C., Maclin, E.L., Fabiani, M., Gratton, G. Hum Brain Mapp., 2008, 29(11), 1288-301.
	Level-set Algorithm for the Reconstruction of Functional Activation in Near-infrared Spectroscopic Imaging. Jacob, M., Bresler, Y., Toronov, V., Zhang, X., Webb, A. J Biomed Opt., 2006, 11(6), 064029.
	Signal and Image Processing Techniques for Functional Near-infrared Imaging of the Human Brain. Toronov, V.Y., Zhang, X., Fabiani, M., Gratton, G., Webb, A.G. Proc SPIE Int Soc Opt Eng., 2005, 5696, 117-124.
	Optimization of the Frequency-domain Instrument for the Near-infrared Spectro-Imaging of the Human Brain Toronov, V., D'Amico, E., Hueber, D.M., Gratton, E., Webb, A., Barbieri, B. Proc. SPIE, 2004, 5312, 378-383.
	Optimization of the Signal-to-Noise Ratio of Frequency-domain Instrumentation for Near-infrared Spectro-Imaging of the Human Brain Toronov, V., D'Amico, E., Hueber, D., Gratton, E., Barbieri, B., Webb, A. Opt. Express, 2003, 11, 2717-2729.

General Review

	Detection of Event-related Hemodynamic Response to Neuroactivation by Dynamic Modeling of Brain Activity. Aqil, M., Hong, K.S., Jeong, M.Y., Ge, S.S. Neuroimage., 2012, 63(1), 553-68.
	Cortical Brain Imaging by Adaptive Filtering of NIRS Signals. Aqil, M., Hong, K.S., Jeong, M.Y., Ge, S.S. Neurosci Lett., 2012, 514(1), 35-41.
	Review: Near Infrared Brain and Muscle Oximetry: From the Discovery to Current Applications Ferrari, M., Quaresima, V. JNIRS, 2012, 20, 1-14.
	Review: Functional Near Infrared Optical Imaging in Cognitive Neuroscience: An Introductory Review Cutini, S., Basso Moro, S., Bisconti, S. JNIRS, 2012, 20, 75-92.
	A Brief Review on the History of Human Functional Near-infrared Spectroscopy (fNIRS) Development and Fields of Application. Ferrari, M., Quaresima, V. Neuroimage., 2012, 63(2), 921-35.

EROS

Cognitive Neuroscience

Auditory Cortex

	The Influence of Posterior Parietal Cortex on Extrastriate Visual Activity: A Concurrent TMS and Fast Optical Imaging Study. Parks, N.A., Mazzi, C., Tapia, E., Savazzi, S., Fabiani, M., Gratton, G., Beck, D.M. Neuropsychologia., 2015, 78, 153-8.
	Preattentive Change Detection Using the Event-related Optical Signal. Tse, C.Y., Penney, T.B. IEEE Eng Med Biol Mag., 2007, 26(4), 52-8.
	Event-related Optical Imaging Reveals the Temporal Dynamics of Right Temporal and Frontal Cortex Activation in Pre-attentive Change Detection. Tse, C.Y., Tien, K.R., Penney, T.B. Neuroimage., 2006, 29(1), 314-20.

Motor Cortex

The Event-related Optical Signal to Electrical Stimulation of the Median Nerve. Maclin, E.L., Low, K.A., Sable, J.J., Fabiani, M., Gratton, G. Neuroimage., 2004, 21(4), 1798-804.

Visual Cortex

	Fast Optical Signal in Visual Cortex: Improving Detection by General Linear Convolution Model Chiarelli, A.M., ChiarelliDi Vacri, A., Romani, G.L., Merla, A. Neuroimage., 2013, 66, 194-202.
	Time Course of Activation of Human Occipital Cortex Measured with the Event-Related Optical Signal (EROS) Gratton, G., Low, K.A., Maclin, E.L., Brumback, C.R., Gordon, B., Fabiani, M. Biomedical Optics, 2006.

Frontal Cortex

	Time Course of Activation of Human Occipital Cortex Measured with the Event-Related Optical Signal (EROS) Gratton, G., Low, K.A., Maclin, E.L., Brumback, C.R., Gordon, B., Fabiani, M. Biomedical Optics, 2006.
	Fast Optical Imaging of Frontal Cortex During Active and Passive Oddball Tasks. Low, K.A., Leaver, E., Kramer, A.F., Fabiani, M., Gratton, G. Psychophysiology., 2006, 43(2), 127-36.
	Dynamic Brain Imaging: Event-Related Optical Signal (EROS) Measures of the Time Course and Localization of Cognitive-Related Activity Gratton, G., Fabiani, M. Psychosonomic Bulletin & Review, 1998, 5, 535-563.

Language Center

	Cortical Dynamics of Semantic Processing During Sentence Comprehension: Evidence From Event-related Optical Signals. Huang, J., Wang, S., Jia, S., Mo, D., Chen, H.C. PLoS One., 2013, 8(8), e70671.
	Imaging Cortical Dynamics of Language Processing With the Event-related Optical Signal. Tse, C.Y., Lee, C.L., Sullivan, J., Garnsey, S.M., Dell, G.S., Fabiani, M., Gratton, G. Proc Natl Acad Sci U S A., 2007, 104(43), 17157-62.

Technical Development

	Establishing the functional connectivity of the frontotemporal network in pre-attentive change detection with Transcranial Magnetic Stimulation and event-related optical signal. Tse, C.Y., Long-Yin, Y., Lui, T.K., Xiao, X.Z., Wang, Y., Chu, W.C.W., Parks, N.A., Chan, S.S., Neggers, S.F.W. Neuroimage. 2018 Jun 18. pii: S1053-8119(18)30560-3. doi: 10.1016/j.neuroimage.2018.06.053. [Epub ahead of print]
	Validation of a Method for Coregistering Scalp Recording Locations With 3D Structural MR Images Whalen, C., Maclin, E.L., Fabiani, M., Gratton, G. Hum Brain Mapp., 2008, 29(11), 1288-301.
	Improving the Signal-to-Noise Ratio of Event Related Optical Signals (EROS) by Manipulating Wavelength and Modulation Frequency Maclin, E.L., Low, K.A., Fabiani, M., Gratton, G. IEEE Engineering in Medicine and Biology Magazine, 26(4), pp. 47-51, July-Aug. 2007.
	Effects of Measurement Method, Wavelength, and Source-detector Distance on the Fast Optical Signal Gratton, G., Brumback, C.R., Gordon, B.A., Pearson, M.A., Low, K.A., Fabiani, M. Neuroimage., 2006, 32(4), 1576-90.
	Lagged Covariance Structure Models for Studying Functional Connectivity in the Brain Rykhlevskaia, E., Fabiani, M., Gratton, G. Neuroimage., 2006, 30(4), 1203-18.
	Optimum Filtering for EROS Measurements Maclin, E.L., Gratton, G., Fabiani, M. Psychophysiology., 2003, 40(4), 542-7.
	The Event-related Optical Signal (EROS) in Visual Cortex: Replicability, Consistency, Localization, and Resolution Gratton, G., Fabiani, M. Psychophysiology., 2003, 40(4), 561-71.
	Toward Noninvasive 3-D Imaging of the Time Course of Cortical Activity: Investigation of the Depth of the Event-related Optical Signal Gratton, G., Sarno, A., Maclin, E., Corballis, P.M., Fabiani, M. Neuroimage., 2000, 11(5 Pt 1), 491-504.
	Bootstrap Assessment of the Reliability of Maxima in Surface Maps of Brain Activity of Individual Subjects Derived with Electrophysiological and Optical Methods Fabiani, M., Gratton, G., Corballis, P., Cheng, J., Friedman, D. Behavioral Research Methods, Instruments, & Computers, 1998, 30, 78-86.

General Review

	Fast Optical Signals: Principles, Methods, and Experimental Results Gratton, G., Fabiani, M. In Vivo Optical Imaging of Brain Function, 2009, 2, 223-247.
	Optical Imaging Gratton, G., Fabiani, M. Neuroergonomics: The Brain at Work, 2007, 65-81.
	Biosignal Processing Gratton, G. Handbook of Psychophysiology, 2007, 3, 834-858.
	Optical Imaging of the Intact Human Brain Fabiani, M., Schmorrow, D.D., Gratton, G. IEEE Eng Med Biol Mag., 2007, 26(4), 14-6.
	Lagged Covariance Structure Models for Studying Functional Connectivity in the Brain Rykhlevskaia, E., Fabiani, M., Gratton, G. Neuroimage., 2006, 30(4), 1203-18.
	Seeing Right Through You: Applications of Optical Imaging to the Study of the Human Brain Gratton, G., Fabiani, M., Elbert, T., Rockstroh, B. Psychophysiology, 2003, 40(4), 487-491.
	Fast Cerebral Functional Signal in the 100-ms Range Detected in the Visual Cortex by Frequency-domain Near-infrared Spectrophotometry Wolf, M., Wolf, U., Choi, J.H., Toronov, V., Paunescu, L.A., Michalos, A., Gratton, E. Psychophysiology., 2003, 40(4), 521-8.
	Shedding Light on Brain Function: The Event-related Optical Signal. Gratton, G., Fabiani, M. Trends Cogn Sci., 2001, 5(8), 357-363.
	The Event-Related Optical Signal: A New Tool for Studying Brain Function. Gratton, G., Fabiani, M. Int J Psychophysiol., 2001, 42(2), 109-21.
	Fast Cerebral Functional Signals in the 100 ms Range Detected by Frequency-domain Near-infrared Spectroscopy Wolf, M., Wolf, U., Choi, J.H., Toronov, V., Paunescu, L.A., Michalos, A., Gratton, E. NeuroImage, 2000, 11(5), 521-8.