Yoga and Its Impact on Neuroplasticity: A Medical Perspective

Yoga, an ancient mind-body practice, has gained recognition for its benefits in improving mental and physical health. Recent studies have focused on the biochemical effects of yoga, particularly its influence on brain-derived neurotrophic factor (BDNF). BDNF, a neurotrophin critical for neuroplasticity, cognitive function, and mental health, plays a vital role in brain development and resilience against neurological disorders. This article explores the relationship between yoga and the upregulation of BDNF, highlighting the potential therapeutic implications of yoga in neuroplasticity.

• In healthy volunteers, the mean plasma BDNF level is approximately 92.5 pg/ml
• BDNF levels are higher in women compared to men and decrease with age in both genders.
• Lower plasma BDNF levels have been associated with advancing age and body weight.
• Beyond the brain, BDNF is also expressed in various other tissues including the lungs, heart, spleen, gastrointestinal tract, liver, fibroblasts, vascular smooth muscle cells, and thymic stroma.

Mechanisms of BDNF Regulation Through Yoga

The exact mechanisms by which yoga influences BDNF levels are not fully understood, but several pathways have been proposed:

1. Asanas: Asanas is a well-known modulator of BDNF. Yoga involves various postures (asanas) that range from gentle to vigorous, depending on the style and intensity of practice. The physical aspect of yoga is believed to stimulate BDNF production, similar to aerobic exercises like running or cycling.
2. Pranayama: Pranayama, has been shown to reduce stress and modulate the autonomic nervous system. Stress reduction is crucial because chronic stress and elevated cortisol levels are associated with decreased BDNF. By promoting relaxation and reducing stress, pranayama may indirectly increase BDNF levels.
3. Dhyana: Mindfulness meditation enhances focus, and emotional regulation, and reduces the grey matter volume in the amygdala, the brain region involved in stress response. This reduction in stress may contribute to the upregulation of BDNF.
4. Karma Yoga - Social interactions provide cognitive stimulation through conversation, problem-solving, and emotional exchange. This cognitive engagement can enhance brain function and promote BDNF expression.
5. Diet - A balanced diet rich in antioxidants, healthy fats, and low in processed foods helps reduce inflammation and oxidative stress, both of which can impact BDNF levels.

Function of BDNF

Activation of TrkB Receptor

When BDNF binds to the TrkB receptor, it activates several intracellular signaling cascades, including those involving Ras, MAP kinase, PI3-kinase, and phospholipase-C-γ (PLC-γ). This activation initiates a range of cellular responses essential for neuronal growth and function:

1. Ras/MAPK/ERK Pathway: Ras subsequently activates the MAPK/ERK pathway, which promotes neurogenesis and cell survival by inducing prosurvival genes and inhibiting pro-apoptotic proteins such as BAD.
2. IRS-1/PI3K/AKT Pathway: Activated Ras stimulates PI3K, which then activates Akt. Akt promotes cell survival by sequestering pro-apoptotic proteins and preventing their action, highlighting its critical role in neuroprotection.
3. PLC/DAG/IP3 Pathway: BDNF binding leads to PLC-γ phosphorylation, breaking down membrane lipids into IP3 and DAG. IP3 increases intracellular calcium levels, while DAG regulates protein kinase C (PKC), crucial for MAPK/ERK signaling. This pathway is involved in neurite outgrowth and other cellular responses vital for neuronal function.

Neurogenesis

1. Developmental Role - Exogenous BDNF has been shown to enhance dendritic length and complexity in pyramidal neurons of the visual cortex, indicating its role in both promoting neuronal growth and guiding dendritic patterning.

Synaptic Plasticity

1. Pre-Synaptic Mechanisms BDNF is essential for regulating pre-synaptic vesicle cycling, which depends on NMDA receptor activation. In BDNF-knockout mice, deficits in pre-synaptic vesicle cycling have been observed, highlighting BDNF’s role in maintaining synaptic function.
2. Post-Synaptic Mechanisms BDNF application to hippocampal neurons restores actin polymerization and long-term potentiation (LTP) stability. It increases NMDA receptor levels and intracellular calcium concentrations, enhancing synaptic activity and plasticity.
3. Synaptic Activity and Calcium Influx BDNF facilitates NMDA receptor trafficking and calcium influx, which leads to increased pre-synaptic vesicle cycling and enhanced LTP. This effect underscores BDNF’s role in promoting long-term changes in synaptic activity and strengthening synaptic connections.

Protocol of Yoga

Asanas

Dynamic Asana: Sun Salutations (Surya Namaskar)

Standing Asanas

1. Warrior II (Virabhadrasana II)
2. Tree Pose (Vrksasana)
3. Chair Pose (Utkatasana)
4. Mountain Pose (Tadasana)
5. Extended Side Angle Pose (Utthita Parsvakonasana)

Sitting Asanas

1. Lotus Pose (Padmasana)
2. Easy Pose (Sukhasana)
3. Seated Forward Bend (Paschimottanasana)
4. Bound Angle Pose (Baddha Konasana)
5. Seated Twists (Ardha Matsyendrasana)

Prone Asanas

1. Cobra Pose (Bhujangasana)
2. Locust Pose (Salabhasana)
3. Bow Pose (Dhanurasana)
4. Superman Pose
5. Plank Pose (Phalakasana)

Supine Asanas

1. Legs-Up-The-Wall Pose (Viparita Karani)
2. Supine Bound Angle Pose (Supta Baddha Konasana)
3. Bridge Pose (Setu Bandhasana)
4. Corpse Pose (Savasana)
5. Reclining Spinal Twist (Supta Matsyendrasana)

Pranayamas

1. Alternate Nostril Breathing (Nadi Shodhana)
2. Kapalabhati (Skull Shining Breath)
3. Bhramari (Humming Bee Breath)
4. Sheetali Pranayama (Cooling Breath), or ANY

Meditation Practices

1. Mindfulness Meditation
2. Loving-Kindness Meditation (Metta)
3. Transcendental Meditation
4. Body Scan Meditation, or ANY

Dietary Changes

Guidelines:

• Incorporate: Fruits, vegetables, whole grains, lean proteins, and healthy fats.
• Minimize: Processed foods, added sugars, and trans fats.
• Hydrate: Maintain adequate hydration with water and herbal teas.

Fasting -? Common protocols include the 16/8 method (16 hours of fasting, 8-hour eating window) or the 5:2 method (5 days of normal eating, 2 days of restricted calories).

Omega 3 -1000-3000 mg of combined EPA and DHA daily, depending on individual health needs and goals.

Green Tea - Dosage: 1-2 cups of green tea daily.

Curcumin Dosage: 500-1000 mg of curcumin daily, often divided into 2-3 doses. The dosage can vary based on individual tolerance and health goals.

Vitamin D - Dosage: Aim for a daily intake of 600-800 IU of Vitamin D for general health. For individuals with low levels, higher doses (up to 2000 IU) may be necessary.

Benefits of increased BDNF

• Improved Learning and Memory: BDNF supports synaptic plasticity, which is essential for learning and memory formation.
• Neurogenesis: BDNF promotes the growth and differentiation of new neurons, particularly in the hippocampus, a brain region critical for learning and memory.

• Reduced Depression: Elevated BDNF levels are linked to reduced symptoms of depression.
• Stress Resilience: Increased BDNF enhances the brain's ability to cope with stress, improving emotional resilience and reducing anxiety.

• Neuroprotection: BDNF provides protection against neurodegenerative diseases by supporting neuron survival and function, and reducing neuroinflammation.

• Protection Against Neurodegeneration: Higher BDNF levels have been associated with a lower risk of neurodegenerative diseases such as Alzheimer’s and Parkinson’s disease.
• Cellular Health: BDNF helps protect neurons from oxidative stress and apoptosis (cell death), supporting long-term brain health.
• Slowed Cognitive Decline: Higher BDNF levels are associated with slower cognitive decline in ageing, supporting cognitive function and brain health in older adults.

• Improved Mental Function: Enhanced BDNF levels can help maintain cognitive functions such as executive function, attention, and processing speed.

• Neurorehabilitation: BDNF promotes recovery and rehabilitation following brain injuries by supporting neuronal repair and synaptic plasticity.
• Stroke Recovery: Higher BDNF levels are linked to improved outcomes in stroke recovery, aiding in the restoration of lost functions.

• Protective Effects Against Schizophrenia: BDNF may offer protective effects against certain symptoms of schizophrenia by supporting neuronal health and function.

References

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