At first glance, yoga and neuroscience seem separate. In fact, they are intimately connected.
Yoga is an ancient practice rooted in Indian philosophy that consists of eight limbs, made up of various meditations, breathing exercises, physical postures, moral disciplines, and guided imagery techniques. Since then, yoga has spread and evolved into a global practice with several types, such as Kundalini, Vinyasa, and Ashtanga.
All practice types have one thing in common: harmonizing the mind-body connection and the human-to-nature relationship. In contrast, neuroscience is the study of the nervous system. Yoga and neuroscience converge because the nervous system is the mind-body connection’s relay station. All information transmitted between the mind and the body travels through the nervous system.
HelloYogaWorld launched this Neuroscience blog series to provide insight into the brain, wellbeing, and yoga.
The yogic lifestyle has sparked great interest in the scientific and medical community because of its ability to change the brain’s chemistry, structure, and function. On this blog, we dive deep into various topics related to neuroscience and its connection to yoga. This first post offers the basics about the nervous system, and provides a foundation of knowledge for future posts in this series.
Let’s start with the nervous system as a whole. It is the control center for human life. The nervous system has two major parts: the central and peripheral. They work together as the lifeline which regulates all bodily functions. The central nervous system (CNS) consists of the spinal cord and brain. The peripheral nervous system (PNS) extends externally from the CNS to all other muscles and organs and branches into two sections, the somatic and the autonomic.
The first major section of the nervous system is the CNS. It includes the spinal cord, which is lined with neurons that relay information to and from the body and brain. The brain is the processing center for all internal and external information. There are three sections in the brain: the forebrain, midbrain, and hindbrain.
Together, the midbrain and hindbrain control all involuntary bodily functions. They make up the brainstem.
The hindbrain also consists of the pons, cerebellum, and medulla oblongata. The pons is the bridge that transmits signals from the brainstem to the brain. The cerebellum is vital for coordinating refined muscle movements. It is also the only part of the brain which contains Purkinje cells, a unique cell type capable of processing many signals simultaneously to enable graceful voluntary movements, posture, and balance.
The Medulla oblongata is also part of the brain stem and is where the brain transitions to the spinal cord. It is the control center of vital autonomic functions, such as heart rate, blood pressure, breathing, and involuntary reflexes, such as swallowing and sneezing.
The forebrain is the largest section, making up two-thirds of the brain’s total mass. It controls all voluntary action and contains four lobes (sections) which assist humans to think critically, to speak, and to move.
The four lobes of the forebrain play a major role in human’s ability to process incoming sensory information and choose output behaviors accordingly. Below is a summary of the four lobes and their functions:
The frontal lobe- Higher cognitive processing, critical thinking, speech and language, reasoning, impulse control, voluntary movement, decision making, and attention.
The parietal lobe- Integrating sensory information from the five senses, limb and body position, and spatial awareness.
The temporal lobe- Also dedicated to integrating sensory information, primarily hearing, and secondarily making sense of complex, abstract visual details. This region assists in language recognition and memory formation. The temporal lobe contains the limbic lobe, which is the emotional processing center. It also consists of the hippocampus, an essential brain region for memory, learning, and emotions.
The occipital lobe- The brain’s major visual processing center receives information from the eyes. After visual information is received, it is relayed to several secondary visual processing areas, which interpret depth, distance, location, and objects.
The second major part of the nervous system is the PNS. As its name suggests, the PNS is part of the nervous system peripheral (external) to the brain and spinal cord.
The PNS includes the somatic nervous system and the autonomous nervous system. The somatic performs voluntary activities, whereas the autonomic nervous system performs vital functions for internal organs. The autonomic nervous system is further divided into two sections: the sympathetic and the parasympathetic. The sympathetic activates fight-or-flight mode and prepares the body’s energy for stressful or energy-exerting activities. The parasympathetic conserves energy and promotes relaxation.
The cells that make up the nervous system are neurons (nerve cells) and glia. Neurons are the transductors of electrical signals and make up the nervous system’s structure. They communicate to process incoming sensory information and send out conscious or unconscious body movements and functions. Glial cells are non-neuronal, but surround the neurons to provide support and nourishment and remove the waste of toxins.
Neurons are highly specialized cells that make up the nervous system’s structure. They contain soma (the cell body where the DNA is located), and extensions called axons and dendrites. Neurons communicate with electrical and chemical signaling. The gaps between neurons are called synapses or the synaptic cleft. A signal is sent through the dendrites and soma and out the axon into the synaptic cleft where it then enters back into the neighboring dendrites. The signal is electrical as it travels through the dendrite, soma, and axons. However, through the synapse, the signals turn into chemical messengers called neurotransmitters. The neurotransmitters work in a specialized way on dendrite’s receptors. Once the signal re-enters the neuron on the receiving dendrites, the signal turns back to electrical.
As a recap, the basic definitions to remember about neurons, which will be beneficial for upcoming blog posts are:
Dendrites- Tree-like structures that branch out from the soma. Dendrites are the messaging receivers from neighboring neurons. The number of dendrites on each neuron varies with an average of 5-7 dendrites.
Soma or Cell Body- Contains the nucleus (genetic information) and other specialized organelles and maintains neuron structure.
Synapses- specialized junctions (gaps) between neurons that convert electrical signals into chemicals through the release of neurotransmitters.
Neurotransmitters- Molecules that bind to receptors on the dendrite to tell other neurons to carry out specific messages.
Furthermore, there are five types of glial cells, all of which help the metabolic function of neurons and ensure their health and integrity. The five types are Schwann Cells, Oligodendrocytes, Microglial Cells, Ependymal Cells, and Astrocytes. We will not study glial cells in detail, but it is important to know that neurons and glial cells are the basic units of the nervous system.
The next topic that will be discussed often are neural circuits (also called neural networks), which are clusters of neurons and glial cells that work together to carry out various duties of the nervous system. They organize in bulk arrangements to carry out functions, such as reflexes like sneezing and more complex tasks like cognitive processes and behavioral control.
The critical information to remember about neural circuitry regarding yoga is that not all neural circuits are present at birth. Throughout life, one can alter neural circuitry. Changing habits can be successful with conscious awareness, repetition, and understanding what is required for the age and brain development stage. We will discuss this topic often and how it also relates to epigenetic changes beneficial for mental and physical health.
In conclusion, we discussed the nervous system’s sections, the types of cells making up the nervous system, and how neurons and glial cells communicate and organize themselves in circuits to process incoming senses and drive bulk movement. This post can be referenced for blogs to come.
The purpose of life is to know yourself and your maker, love yourself and the people around you, and live the fullest expression of your soul.
Not understanding the nervous system and the mind-body connection is equivalent to a gardener planting crops without understanding how to use the proper tools. Understanding the tool we have been gifted breaks the barriers which prevent us from living our fullest potential.