What Are the Pros and Cons of Deep Brain Stimulation for Parkinson's?

Light stimulation is a series of stimuli caused by light. Among them, the use of infrared, ultraviolet, visible light, X-rays and lasers to stimulate the skin of acupuncture points can play a therapeutic role. Irregular amplitude modulation laser with adjustable strength is a promising treatment method ^[1] .

Photostimulation is considered a category of photochemical reactions, but the term "photostimulation" is not well defined scientifically. Most light stimulation studies involve low-energy-density lasers, which have been the subject of controversial research for decades. A typical energy density that causes photostimulation is 1 to ¹⁰ J / cm ² and usually does not cause an exact temperature rise. Some scientists have limited light stimulation to the absence of any thermal mechanism (such as the use of 1064nm wavelength light, high repetition frequency and low energy density, which can make the skin delicate and shiny).

Light stimulation leads to changes in hormone levels, bringing cosmetic effects;

Light stimulates the autonomic nerves (sympathetic and parasympathetic nerves), and the autonomic nerves are changed, which leads to changes in body functions and brings about cosmetic effects;

Low-energy irradiation of the target site causes changes in the amount of some factors in the tissue, resulting in changes in body functions and a slight cosmetic effect.

The change brought about by light stimulation is the change of the low-light environment, which is invisible to human eyes, but it does exist. There is also vague evidence that low-energy-density lasers accelerate wound healing, and the mechanism is unclear.

Light prenatal education mainly uses the light of a flashlight to enter the uterus through the abdominal wall and muscles. The light in the uterus will turn red after passing through the amniotic fluid, which is a fresh visual stimulus for the dark baby.

When the rod cells of the fetal baby's retina feel the change of light, the information of this light change will be transmitted between brain cells in the form of electrical pulses, and the visual neural pathways that are passed during the transmission process will be developed. It is possible to extend more dendrites or dendritic spines on the basis of these cells, thereby laying the foundation for forming a richer optic nerve network ^[2]

Some experts in sleep research in England say that too much light before going to bed will inhibit the brain's production of melatonin, disrupt the circadian clock, and affect normal sleep. Some people are particularly sensitive to this. Japanese scientists have also found that people who often use mobile phones, computers and other electronic devices at night will reduce their sleep quality and their body's metabolism rate will decrease, resulting in drowsiness and loss of energy the next day.

A study conducted in the United States on young children and adolescents aged 2 to 16 found that vision is quite closely related to the brightness of sleeping light sources before the age of 2 years. Many parents are worried that their children will be scared when they wake up in the dark, so they like to turn on the lights to let their children sleep, which is not good for their eyesight, because young children's eye development is not perfect and they are stimulated by artificial light for a long time. Easy to induce myopia. Parents are advised to turn off the lights as soon as possible when they accompany their children to sleep, so that outdoor natural light sources can adjust the indoor brightness, which is more beneficial to the child's health ^[3]

With the rapid economic development and increasing social competition pressure, the incidence of various neuropsychiatric diseases has also increased rapidly. Mental illness has become a type of illness that seriously affects the physical and mental health of the Chinese people, placing a heavy burden on patients' families and the entire country and society. The pathogenesis of these diseases is not clear, and intervention and treatment methods are limited. Traditional medical treatment is an important method for the treatment of neuropsychiatric diseases. Although the symptoms of some patients can be relieved through drug treatment, about 10% of patients with mental illness cannot effectively control the occurrence of the disease after 2 or even 5 years of drug treatment.

Neuromodulation technology is a reversible treatment. It mainly uses electrical, magnetic or optical stimulation to change the activity of specific neural circuits in the brain to achieve the purpose of treating diseases. There are three main neuromodulation techniques that can be used for neurological intervention and regulation of body cells, including Deep Brain Stimulation (DBS), Transcranial Magnetic Stimulation (TMS), and Optogenetics.

DBS is essentially an electrical stimulation process. Clinically, electrodes are used to stimulate the corresponding parts of the nerve center. It has a certain therapeutic effect on certain diseases such as epilepsy and Parkinson's disease. However, DBS itself has side effects due to lack of cell specificity. In addition, the electrode can be insulated for several months to several years due to the formation of glial cell scars. Furthermore, the mechanism of DBS's effect on certain diseases still not clear.

TMS plays a therapeutic role by depolarizing excited nerve cells through an electric field. It can be used to treat neuropsychiatric diseases such as schizophrenia, Parkinson's disease, major depression, stroke, and chronic pain. But TMS can only stimulate a few centimeters of the surface of the brain, not deep neurons. Like DBS, TMS cannot achieve neuronal suppression and specific stimulation of specific cell subtypes.

Optogenetics is based on gene therapy methods. Viral vectors are used to introduce light-sensitive channels or pump protein genes into a specific subpopulation of cells for expression. One type of light-sensitive channel protein (Channelrhodopsin-2, ChR2) is sensitive to blue light. Blue light can activate the channel, and Na +, K + and other cations enter the cell to excite the cell; the other chloride ion protein (Halorhodopsin, NphR) Sensitive to yellow light, which will allow Cl- to enter the cells and inhibit the cells. This technology overcomes the shortcomings of lack of cell selectivity in traditional pharmacological tools or electrical stimulation modes, and has a higher spatiotemporal resolution compared to other forms of stimulation ^[4] .