The Role of NIRS in Brain Training, Mindfulness, and Stress Reduction
Near-infrared spectroscopy (NIRS) is at the heart of Thinkie. While the technology has been around for quite some time, it has more recently emerged as a valuable tool for measuring brain activity. Thinkie measures cerebral blood flow in the prefrontal cortex (PFC) to gauge brain activity during training.
In similar fashion, NIRS can be used to measure activity in the Default Mode Network (DMN), particularly in the medial prefrontal cortex (mPFC), a key component of the DMN. NIRS offers several advantages for studying DMN activity, including its ability to measure cerebral blood flow changes non-invasively and with fewer physical constraints compared to fMRI.1
Envision Thinkie as a river representing these two aspects of the brain: the rushing, teeming side of brain training giving way to the quieter, more contemplative pool that is mindfulness and stress management. Above both sits Thinkie, connecting the two – just like the Thinkie sensor sits on your forehead, just beyond the brain.
Studies using NIRS have revealed important insights into DMN activity. Consistent with fMRI findings, NIRS measurements show that the magnitude of spontaneous activity in the mPFC decreases with age in healthy subjects.1 This decrease in spontaneous activity corresponds to a sense of relaxation and well-being in the subject. In other words, lower activity is desired in the mPFC to manage stress levels, while higher activity in the PFC is the goal for brain training.
DMN activity is affected by stress levels in several ways:
- Meditation: Studies have shown that meditation, which involves focusing on breathing and relaxation, is associated with reduced activity in the DMN.2 This reduction in DMN activity appears to be related to decreased mind-wandering and increased present-moment awareness
- Mindfulness: A recent study found that one month of mindfulness meditation effectively increases interconnectivity between the DMN, Salience Network (SN), and Central Executive Network (CEN).3 This suggests that mindfulness practices may modulate DMN activity and its interactions with other brain networks
- Stress impact: Stress has been found to affect the activation-deactivation pattern of resting state networks, including the DMN. Stressed individuals show greater activation of the DMN and impairments in the deactivation of resting state networks compared to controls4
- Neurofeedback: Mindfulness-based fMRI neurofeedback (mbNF) has been developed to reduce DMN hyperconnectivity, particularly in adolescents with depression.5 This approach aims to modulate DMN activity through mindfulness practices, coupled with real-time feedback to gauge their efficacy
It’s been well established that NIRS serves a vital role in supplying real-time feedback for brain training. In addition, NIRS can prove a valuable method for studying DMN activity, particularly in the mPFC. The relationship between stress reduction techniques, such as meditation and mindfulness, and DMN activity is complex but generally involves a reduction or modulation of DMN activation.
As a consequence, there is potential for stress reduction techniques to influence brain network dynamics, which may give rise to possible therapeutic applications. More on that topic in a future post.
2 Default mode network - wikipedia
3 Mindfulness meditation increases default mode, salience, and central executive network connectivity