What Do Master Teachers Do? Teach & Repeat

My first mindfulness teacher, Dr. Gus Castellanos, writes an informative and wonderfully honest newsletter called Inner Inmate Wisdumb, Mindfulness, and Such. The title speaks volumes about his originality and eagerness to infuse humor into the teachings. It also says a lot about how we as teachers can demystify a simple, noble practice.

Gus was an understated teacher, leading post-meditation inquiry with deliberate pauses. I recall his unassuming presence in front of the camera, modest and innocent, even while demonstrating mindful movements. This can be quite hard to pull off when you’re a mature, accomplished man with a medical degree. A few years later, after reading several of his newsletters, I ultimately reached out to him. I wanted to tell him about my own mindfulness journey and seek his perspective. Like all Master Teachers, he responded promptly and with kindness. I greatly appreciated his willingness to accommodate me in spite of his busy schedule.

Many people ask questions about mindfulness like: What is it, exactly? How did your interest in the practice develop? What happens during meditation? What drives people to explore Mindfulness Based Stress Reduction strategies? What are the neurological effects? And so forth. While there are shared fundamental principles, each practitioner and teacher will provide unique responses. Personally, I never get tired of asking about the practice. I truly believe mindfulness itself embodies a constant state of openness and curiosity and only through shared inquiry do we raise our consciousness. 

Today, I’m sharing Gus’s responses to some of these basic questions as a means of expressing my respect and gratitude for his life’s work and offerings.

What got you interested in mindfulness? I came to mindfulness through a Mindfulness Based Stress Reduction (MBSR) course in 1998. I was practicing medicine, having lots of job-related stress, and coping with the stress maladaptively. Practicing medicine caused me stress with little self-awareness. I was “treating” myself by using Rx meds inappropriately, acting out, and isolating myself. I was told by close friends and family that I needed help, but I was in denial. Then fortuitously, MBSR was brought to the hospital where I worked. Being curious about meditation and yoga and at the request of the doctor friend who brought MBSR to the hospital, I decided to try it out. At first, I went to see what it was about and how it may help my patients, but half way through, I knew I was the one that needed the help. I then participated with the intent of relieving my own suffering and less so to see how it could help others. 

Why mindfulness training, as opposed to other types of therapeutic/wellness programs and approaches? We say MBSR is therapeutic, but not therapy. MBSR is considered a psychoeducational program based on experiential learning and group processing. That is, the benefits derived from MBSR are grounded in engaging with the practices, exercise, inquiry, and group discussions. 

Isn’t meditation a central component of mindfulness? If so, why not just call it learning meditation? Mindfulness and meditation are not the same. Meditation is a general term for a number of different practices, just like the word exercise, which includes many different activities. Mindfulness is about being aware in the present moment of what is happening, as it is happening. It can be cultivated in everyday activities. And, it is also cultivated with mindfulness meditation.

From a neurological perspective, can you explain what happens with consistent mindfulness meditation practice? The changes in the brain brought about by mindfulness have been studied quite a bit, but the science is still young. The changes are related to the practice and the intent of the research. Some of the changes include: mindfulness training increases/enhances: Prefrontal cortex (attention, impulse control, critical thinking, rationality, planning), Hippocampus (memory, learning), Anterior Cingulate Cortex (meta-awareness, compassion, emotion regulation) and Insula (body awareness, salience, empathy). Mindfulness training decreases: Amygdala (stress response, emotional valence) and Default Mode Network (mind wandering, self-referential & self-critical thinking, mental time traveling). Mindfulness alters the brain to oppose chronic stress, which decreases the activity of the prefrontal cortex and hippocampus; and increases the amygdala.

What are some patterns and trends you notice with regards to client needs and concerns? In the post-pandemic era, trends include a significant increase in anxiety, depression, loss, trauma, and substance use disorders. Chronic pain and insomnia are also common. Others are looking to mindfulness for performance enhancement and increasing resilience.

What criteria should people keep in mind when looking for a mindfulness teacher? Who are they trained by or certified by? How long have they been teaching? What groups of people are they most experienced teaching? Do they have a personal practice? If so, what is it?

Does mindfulness training naturally lead to feelings of loving kindness towards others? If so, what is loving kindness, exactly? Is this related to wanting to do acts of service? Mindfulness training has been shown to increase compassion and empathy, although training specifically for these will foster them more. Mindfulness is a pro-social practice, depending on the actual training. I am probably not the best person to answer what Loving Kindness is, but there are many teachers and practitioners who focus on this topic.


Dr. Gus Castellanos is a retired Neurologist and Sleep Specialist, UMass certified MBSR teacher, and long-time meditator. You can learn more about him at https://innerinmate.com/home/