Table of Contents
Brain disorders and parvalbumin cells
Alzheimer’s disease and schizophrenia are considered to be the most common brain disorders, which are the result of problems in cells containing parvalbumin protein that represent almost one-tenth of all brain cells, but relatively little is known about their operation. Researchers from the USA have started to study the principle of cell operation by stimulating mouse brains with laser systems.
Custom-built fiber laser for brain research
A custom-built laser system has allowed the researchers from Washington University to find the connection among activity in specific inhibitory neural circuits, cerebral blood flow, and volume. Fiber laser demonstrated that higher activity, in particular inhibitory neural circuits, decreases cerebral blood flow and volume, while excitatory activity evokes blood flow and volume to increase.
Unexpected findings in blood flow and volume
The researchers discovered unexpected changes in blood volume and flow during stimulation of cells, including parvalbumin protein. The used laser technology is based on specially bred mice whose brains are stimulated with laser beam pulses.
Optogenetics technology and its advantages
The method of brain stimulation with light signals from the laser module, called optogenetics, has enlarged the understanding of brain operation as well as the brain processes of fear, sense of smell, and even the reason for drug addiction.
Mechanism of fiber laser stimulation
Optogenetics technology with a fiber laser system is convenient, less invasive, repeatable, and easy to use because this technique does not require putting any probes into the mouse brain. The principle of laser technology operation is quite simple; the researchers hit the necessary area of the mouse brain with the red colored laser beam, therefore, a desired neural circuit is activated.
Blood and oxygen response in neural circuits
More neurons are stimulated, and more blood and oxygen are produced. At the same time, the use of the laser system enabled to finding of the opposite response during the stimulation of parvalbumin-expressing cells. This connection between activity in specific neural populations and local changes in blood flow plays a crucial role in the regulation of blood supply by the brain.
Laser speckle contrasting imaging and measurements
The fiber laser technology reveals that parvalbumin-expressing cells are able to pull back and fine-tune the blood supply in areas where they are activated. A separate laser system technology, called laser speckle contrasting imaging, allowed researchers to measure the exact blood and oxygen levels that significantly reduced when parvalbumin cells were excited.
Long-range communication of parvalbumin cells
Parvalbumin cells were the way to transmit messages to faraway parts of the brain to change their hemodynamics, or blood flow, as well. In fact, the information obtained by the laser system will provide a better understanding of parvalbumin’s role in neurovascular coupling, demonstrating its influence on brain development or the emergence of neurological disorders.