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Functional Optical Brain Imaging Sensor utilizing Near Infrared
TechnologyAta Akin, Banu Onaral, Kambiz Pourrezaei
Drexel UniversityScott Bunce
MCP Hahnemann UniversityBritton Chance, Shoko NiokaUniversity of Pennsylvania
Sponsors: ONR
Drexel University
Project Overview
•Objectives• Research, development and deployment
of an optical brain monitoring/imaging system based on functional Near Infrared (fNIR) imaging modality.
• Deployment in various health applications where blood oxygenation of the prefrontal cortex is linked to the state of mental engagement and other educational and clinical parameters.
Project Goals
• An integration of a pulse laser/LEDs, low power circuitry, and signal and image processing:• To provide a means to assess the performance of
a pilot or operator,• To measure cognitive over-load,• Compatible with existing legacy and COTS
systems
• Dual use deployment, military and civilian (healthcare, training and education)
Biophotonics Optical techniques for diagnostic and therapeutic
applications
Diagnostics & Imaging Treatment & Surgery
Microscopic< 100m
Macroscopic > 100m
•Two-Photon (multi photon) microscopy•Fluorescence microscopy•Optical Coherence Tomography•Tissue spectroscopy
•X-Ray•Optical Radiation (thermograph)•Diffuse Photon Density Waves
•Photodynamic therapy•Laser surgery
Fields of Application
Dermatology, plastic surgeryCardiovascular interventionsGastrointestinal surgeryBreast cancer diagnosisOphthalmic technologiesDentistryBrain Activity MonitoringMuscular ActivationMetabolism ResearchOthers
Laser tissue interactionTissue engineeringThermal treatment of tissueFunctional imaging of living cells and tissuesMicroscopyMolecular probes and dyesNanoparticlesTumor treatmentMicroarraysOthers
Clinical Applications Basic Sciences
FOCUS OF TODAY’S PRESENTATION
Optical Window in Tissue
Near IR
Light in the 700-900 nm wavelength range (Near Infrared) can penetrate into tissue up to 5-6 cmLight sources working within this range can be used in investigating the optical properties of tissue
800 nm Source: Detects changes in Blood Volume
850 nm Source: Detects changes in oxygenated-Hb ([HbO2])
750 nm Source: Detects changes in deoxygenated-Hb ([Hb])
Physics of Light Tissue interaction
Single Scattering
Multiple Scattering
Diffusion Process
In air
In Clean Water
In Tissue
Activation Areas
Imaging Cognition II: An empirical Review of 275 PET and fMRI StudiesR. Cabeza and L. NybergJ. Cognitive Neuroscience, (12):1, pp. 1-47, 2000
Process Areas
Attention 9
Working Memory (object) 9, 46, 45,44
Semantic Memory Retrieval (Categorization)
45
Episodic Memory Encoding (Object)
6, 9, 46, 45,44
Episodic Memory Retrieval (nonverbal)
10, 9, 44
Probing Brain with Light
K K
Na
ATPase
Neuron
Glia
K
K
Metabolic Factors
K : di lation
H : di lation
adenosine : dilation
Spatial Buffering
ECF
[1] W. Kuschinsky, “Neuronal-vascular coupling, a unifying hypothesis,” in Optical Imaging of Brain Function and Metabolism II, ed. A. Villringer and U. Dirnagl, Plenum Press, 1997
P. J. Magistretti and L.Pellerin, “Metabolic coupling during activation,” in Optical Imaging of Brain Function and Metabolism II, ed. A. Villringer and U. Dirnagl, Plenum Press, 1997
Photon Migration in TissueSource
Detector
Work in Progress
• Noninvasive•Non-intrusive •Safe• Affordable• Portable• Combines spatial resolution and time resolution
COGNISCOPE:BRAIN ACTIVITY MONITOR
Cogniscope• Combination of EEG and fNIR sensors to continuously monitor
neuronal and hemodynamic changes
• Motivation: A need to monitor brain activity with high temporal resolution (10 ms range) to better quantify physiological changes due to external stimuli
• Hypothesis:
• A portable optical brain imaging system can provide a quantitative and fast means of monitoring and imaging cognitive brain activity under mental stress
• The relationship between neuronal (EEG) and hemodynamic activity (fNIR) can be established to evaluate/predict human performance under stress
Cogniscope
• Potential Uses• Cognitive activity engagement
• Classroom evaluation
• Soldier/pilot state monitoring
• Alertness/vigilance assessment
• Mental disorders assessment
• Sleep disorders
• Co-registration with fMRI
• Others…
Headpiece
Receiver
Host Server
Patent Pending
f N I R O p t o d e s E E G E le c t r o d e
F le x C i r c u i t s
B a t t e r i e s
Cogniscope Headband
System on Chip•DAQ•T/R•Power
DSP•Data Fusion•Diagnostics•Alarm
Patent Pending
Long-term Goals
• Develop a quantitative technique to evaluate human performance based on the fusion of several physiological parameters
• Use of multi-modality signal/image acquisition/processing in modeling dynamic interactions between cognition, perception, memory, learning, emotional control mechanisms and decision under stress