fNIRS brain imaging is based on the quantification of hemoglobin (Hb) and deoxy-Hb. The work of D. Boas, BU Neurophotonics Center director and fNIRS brain imaging pioneer is presented at this video by NINDS & partners.
#JHUAPL is one of 6 teams chosen by @DARPA to develop high-resolution, bidirectional brain-machine interfaces for use by able-bodied service members. APL aims to develop a completely noninvasive, coherent optical system for recording from the brain. ⚡️? https://t.co/zQv3wngTd1— Johns Hopkins APL (@JHUAPL) May 20, 2019
Figure 2: Tweet by the APL announcing the DARPA grant
Video 1: https://youtu.be/4gXuOuXZEeo 3min11s: researcher affecting an ultrasonic wave with his hands placed near the sound source, 3min28s: EEG near-infrared sensor
Illumination of brain with infrared light leads to photon scattering resulting in a faint return signal.
By predicting the scattering we can design a holographic pattern for illumination that results in photon focusing in order to obtain a strong signal.
Holography-mediated de-scattering of light.
Holographic illumination of the brain compensating for tissue scattering thereby allowing photon focusing.
Other applications: detections of tumors, stroke
Excerpts from https://www.openwater.cc/faq-1 - Question: "What are the key advantages of the holographic method used in Openwater versus diffuse optical tomography?"
The approach consists of the use of "a novel kind of LCD and detector combination we are pioneering in concert with infrared light sources."
"we make a hologram of the brain or tissue, and invert the hologram with a computational process called phase conjugation to neutralize the effect of the scattering of the brain to make it effectively transparent."
"Then we look at the differential effects of the color change of the blood voxel-by-voxel where oxygen is being consumed (which is exactly what fMRI does, but we do it with an LCD that lines the inside of say a ski-hat)."
"We are also using this system architecture to look at refractive index change of the neuron as its action-potential changes on the millisecond time scale, and the differential scattering of a neuron as its surface roughens in a millisecond as a voltage propagates along it. Neither MRI nor fMRI can look directly at the neurons, we believe we can."
"We are working on using the holographic phase-conjugate approach in reverse as well. As we develop those systems, which will likely ship in subsequent generation products, one can imagine many benefits, such as doing surgery without cutting, ablating tissue, removing plaque from clogged arteries, and the delivery of localized treatments."
"At the extreme we believe we can change neuron states, ideas, and memories with this method."
Technology section of website https://www.openwater.cc/technology
TED Talk (including transcript)
Figure 3: Excerpt from interview by Mary Lou Jepsen - https://www.facebook.com/informationbookcom/posts/482327715440748