Non-invasive low powered lasers are now being applied to specific cortical regions of the brain to elicit physiological and cognitive responses. These lasers are invisible to the human eye with wavelengths of around 600–1000nm.
Low-level laser therapy has the potential to enhance many cortical processes. Researchers are finding promising applications of LLLT for neuroenhancement (attention, memory, reactions), the alleviation of depression, the acceleration of wound healing and possibly even the treatment of Alzheimer’s disease.
In 2017, a study out of the University of Texas, found that participants exposed to low levels of infrared light on the head found an increase in cortical metabolic activity¹. The people that were exposed to the infrared lasers had greater attention and memory and it gave them a superior cognitive edge over a placebo group in a card sorting task. The basic physiological process behind the enhancement is thought to be caused by an enzyme called cytochrome c oxidase, which is found in the mitochondria of the neurons (the ‘powerhouse’ of the cell). In simple terms, the low-level lasers emit photons which are absorbed in the neurons by these enzymes resulting in an increase in ATP production² (which is the basic units of energy storage in cells). The increase in energy production in neurons seems to be the cause for the neuroenhancement.
In other recent research, LLLT is also being used to tackle depression³. Although the research on LLLT for treating depression is scarce, results so far have shown that it could be a promising treatment in the future. Another observed benefit of LLLT is the increase in reaction times of treated participants in a vigilance test⁴ (participants having to hold their attention in delayed intervals and press a button as quickly as possible when a certain stimulus presents on the monitor). A faster reaction time is thought to be due to the increase in attention as a result of the laser therapy. An increase in cellular respiration in the cortical regions relevant to attention (such as the prefrontal cortex and parietal lobe) could be responsible for the enhancement of these phenomena.
Further benefits of LLLT include the regeneration of certain body tissues and cell types such as blood cells. Some of the predicted reasons for this are the increase in cellular respiration and decrease in inflammatory processes, which are induced by cytochrome c oxidase as a result of LLLT⁵. As well as the acceleration of wound healing, the therapy has shown positive results in increasing visual acuity in people with macula degeneration⁶. In a study consisting of four sessions spaced over two weeks, LLLT was administered to people with macula degeneration. The results showed an increase in visual acuity and a reduction in degeneration for over 90% of people. The benefits in visual acuity enjoyed by these people with macula degeneration lasted for up to 36 months.
The regenerative ability of LLLT leads to bigger questions, such as the capability of low-level lases to treat neurodegenerative diseases (such as the infamous Alzheimer’s disease) and stroke. One study found that in stroke-induced rats, LLLT possibly caused neurogenesis (the creation of neurons) reducing the defects associated with stroke⁷. The question of LLLT to treat stroke and neurodegenerative diseases should aim to be answered with an army of experimental research in the future.
But so far, the use of LLLT for many purposes such as the alleviation of depression, the enhancement of cognition (attention, memory and reactions) and the ability to accelerate would healing and regeneration are some of the primary benefits of LLLT and the majority of research so far is very promising.