Photobiomodulation: Another lesser-known way cellphones could affect mental states

While much attention is given to neurotransmitter molecules like serotonin and dopamine, not everyone realizes how much of our activity is connected to certain electrical brainwave patterns. These patterns are directly tied to our emotions, and altering them (modulating) can alter our mental state. Modern cellphones have the ability to do such modulating.

For instance, one type of brainwave, labeled beta waves, affect our alertness and emotions:

Anxiety, insecurity, fear, panic and phobia are observed by QEEG when the levels of total Beta >17% and High-Beta waves >10% at T3 and T4.

https://pmc.ncbi.nlm.nih.gov/articles/PMC6200158/

The human brain is characterized by endogenous oscillatory activity, i.e., rhythmic fluctuations stemming from electrical potentials spontaneously generated by neurons. Such oscillations are the result of synchronized and coordinated electrical activities that describe functional networks across large populations of neurons. It is generally accepted that brain oscillations reflect neural communication and information processing within neural networks (Cole and Voytek, 2017), resulting in distinct patterns of brain wave frequencies. Natural brain frequencies are classified into five bands: alpha (8–12 Hz), beta (15–29 Hz), theta (3.5–7 Hz), delta (0.5–3.5 Hz), and gamma (30–90 Hz). Interestingly, each phase and power of each endogenous frequency range of neural activity was assigned to a functional role in behavior and cognition (Buzsaki, 2004, Van Wassenhove, 2016). The close relationship between changes in brain oscillations and behavior suggests that targeting oscillations could improve cognitive functions. Accordingly, a significant number of studies focusing on brain-behavior relationships were published in the scientific literature. As a result, there has been extensive research into the use of brain stimulation techniques for therapeutic purposes, with the goal of inducing specific frequencies to guide the brain into desired states (for review, see Polanía et al., 2018). 

https://www.sciencedirect.com/science/article/abs/pii/S030645222400321X

Photobiomodulation is a technology that uses delivery of near infrared light pulses to the brain to affect our brain's activity. (See https://pmc.ncbi.nlm.nih.gov/articles/PMC11171912/.) Cellphones shine that type of light onto our eyeballs and onto the interior surfaces of our noses and ears (cellphone proximity sensors* emit near infrared light), meaning they can hypothetically be used to either stir up or reduce alertness and anxiety.

In the intranasal PBM approach, light is positioned within the nostril, allowing the direct irradiation of subcortical and cortical structures associated with the pathologies of AD and PD. Additionally, combining light exposure through the sphenoid sinus and mouth cavity has been proposed to achieve sufficient fluence at the SNc in humans. 

https://pmc.ncbi.nlm.nih.gov/articles/PMC11171912/. Nairuz, T.; Sangwoo-Cho; Lee, J.-H. Photobiomodulation Therapy on Brain: Pioneering an Innovative Approach to Revolutionize Cognitive Dynamics. Cells 2024, 13, 966.

I wonder how many places, knowingly or unknowingly, use infrared lights to calm us as part of a spa or worship experience. 

* "The proximity sensor usually sits up near the top speaker and combines an infrared LED and light detector to work out when you have the phone up to your ear, so that screen can be switched off. The sensor emits a beam of light that gets bounced back, though it’s invisible to the human eye." Downloaded from https://gizmodo.com/all-the-sensors-in-your-smartphone-and-how-they-work-1797121002 on September 9, 2025.