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Treating brain disorders with lasers

brain tissue sample

In the research project NEUROPA Oulu researchers utilize recent progress in photonics, neuroscience and medicine to develop a non-invasive means of modulating specific neural pathways in the brain.

The ultimate goal of the NEUROPA research is to provide treatment and alleviate the long-term brain dysfunction in certain neurodegenerative conditions, such as Huntington’s or Alzheimer’s disease. The project was made possible through a 3.6 ME grant from the European Commission under the Future and Emerging Technology Programme, it will last for three years and started in January. Each partner from different European universities brings to the project specific skills and knowledge from the fields of phytoptogenetics, photonics, genetic engineering and medical imaging.

Phytoptogenetics

In the project the researchers will use light in combination with phytoptogenetics to improve patients’ cognitive abilities. Phytoptogenetics is a form of optogenetics, which is where viral vectors carry genetic instructions for making light-sensitive protein switches called channel-rhodopsins. Long-term modulation of targeted neural network activity will be achieved by activating light-sensitive protein “switches” – phytochromes – in specific neurons located close to the brain surface in Alzheimer’s patients.

The control of neural networks will be implemented through the activation of cortical projecting neurons using infra-red light. Since radiation in this range penetrates the skull and brain tissues better than the blue and green light used in optogenetics, the expression of light-sensitive proteins can be controlled noninvasively using new compact NIR lasers. To do that, new phytochrome viral vectors carrying genetic instructions will be delivered to specific brain regions or cells. The interactive control of the brain cells network activation by photo-switchable phytochromes will be monitored by a variety of optical methods, including the use of diffusing wave spectroscopy blood flow detection.

”The main advantage is that all intervention and monitoring of effects will be selective and non-invasive. Currently, drug treatments for brain disorders as well as transcranial magnetic stimulation has a lack of selectivity in cell targeting,” says scientific project coordinator Alexander Bykov from the Optoelectronics and Measurement Techniques research unit (OPEM) at the University of Oulu.

Optical analogs of biotissues

Noninvasive brain-sensing has been among his and his colleagues research topics for about ten years, developing the methods of brain hemodynamics monitoring. In parallel, they have developed a technology for the manufacturing of optical analogs of biotissues (biotissue phantoms), including the human brain.

”These phantoms are used for calibration of optical measurement techniques and assessment of some specific parameters that are not easy to assess at in vivo measurements, for example the dose of optical radiation that the brains are exposed to during the transcranial illumination,” says Bykov.

The task of his group in NEUROPA will be to develop the optical based technique for sensing brain activity e.g. via blood circulation.

Image caption: Sample of the brain tissue before the characterization with the laser-based imaging system