Tag Archives: The Brain

The Glorious Brain-8

Today, a mishmash of facts about the brain I find fascinating-

1.The cells that form the outer layer of the embryo eventually fold inward and become the very beginning of the spinal cord.  Clusters of these cells gather at one end of the spinal cord to become the skull encased brain.

2. The experiences we have in life cause neural firing. The more neurons (nerve cells) firing together (from repeated experiences of all sorts) the stronger the pathway. As neurons fire together, the genes in the nuclei become activated and produce proteins. Proteins allow synaptic linkages to be constructed or strengthned. Remember-neurons are connected to each other by synapses.

3. Experience also stimulates the production of myelin, a fatty sheath around the axon of the neuron.  This speeds up firing and synaptic connection.

4. Experience also stimulates neural stem cells to differentiate into new neurons.

I often write about mindfulness and tuning into the inner body and its sensations. These experiences, if done consistently, can literally strengthen your brain functioning and change the neural pathways. Well worth the effort!

Somatic Experiencing-9

Peter Levine developed Somatic Experiencing; his latest book, In An Unspoken Voice, is brilliant. I’ve written often about tracking the sensations in the body; today, with the help of this book,  I will go into more detail. The four categories listed below are part of  Peter Levine’s model for tracking sensations in the body.

The physical sensations that arise in the body travel via nerve impulses from the interior of the body to the thalamus in the brain stem (please check earlier posts on areas of the brain).  They are then transferred to most other areas of the brain.   There are four categories:

1. Kinesthetic Receptors-picks up tension in our muscles and sends this information to the brain. When we are particularly tense, we receive an excess of nerve impulses coming from the the sight of the tension, maybe the shoulders, neck, pelvis, etc. causing us to feel uncomfortable and ‘uptight’.

2. Proprioceptive Receptors-gives us positional information about our joints.  Working with kinesthesia, proprioception tells us where we are in space.

3.Vestibular Receptors-There are microscopic hairs in the semicircular canals of the inner ear, the two canals are at right angles to each other.  When we move, fluid in these canals bends the hairs.  Each hair is connected to a receptor that sends messages to the brain.  It is here we learn our position in regard to gravity and movement.

4. Visceral Receptors-This is the deepest level of sensation and involves our blood vessels and viscera(internal organs).  We feel open, flowing, relaxed and warm when our viscera and blood vessels are open, anxious and cold when constricted.

Autonomic Nervous System-2

I’m excited about something I just read about the ANS (autonomic nervous system) and want to tell you all about it but first, a quick review.

As you may recall from earlier posts, the ANS is coordinated in the middle prefrontal area of the brain.  It is coordinates bodily functions such as heart rate, respiration and digestion.  It is comprised of two branches:sympathetic which functions as the accelerator and parasympathetic which works as the brake. Fight or flight (please see earlier post) occurs here.

David Eagleman’s fascinating new book, Incognito,The Secret Lives of The Brain, is filled with scientific studies documenting unconsciousness:there is so much going on in our brains, affecting every aspect of our livest, that we know nothing about.  I’m going to write about some of these studies and facts-let me know what you think.

Antoine Bechara, a neuroscientist, tested (1997) the validity of hunches. Her team placed four decks of cards in front of subjects and asked them to choose one card at a time.  Each card represented a gain or a loss of money.  Slowly, the subjects realized each deck had a theme:two of them were “good,” meaning they would make money and two were “bad,” representing a loss.

As they thought about which deck to draw from, they were interrupted at various points by the investigators and asked which decks were good, which bad. It usually required about twenty-five draws from the decks to make this determination.

At the same time they measured the subject’s skin conductance response, which reflects the activity of the autonomic nervous system (fight/flight). The ANS picked up the statistics of the decks long before the conscious mind did! When the subjects reached for bad decks, there was an anticipatory spike in activity (sympathetic branch)-a warning sign! This was picked up by the thirteenth draw; well before the conscious mind. This information was being delivered in the form of a hunch; subjects began to select the good deck before they knew why!

Studies like this one led scientists (Damasio, et al)  to propose that the feelings produced by physical states of the body guide behavior and decision making. “When something bad happens, the brain leverages the entire body (heart rate, contraction of the gut, weakness of the muscles, etc) to register that feeling and that feeling becomes associated with the event.  When the event is next pondered, the brain essentially runs a simulation, reliving the physical feelings of the event.Those feelings then serve to navigate, or at least bias, subsequent decision making.” Eagleman, 2011)

This makes me think about SE and meditation.  It’s so important to tune inward to pick up the sensations of our body-they come directly from the brain.  There is a wealth of knowledge here on every single level-we only have to turn inwards and listen.

The Glorious Brain-7


The brain of a young child is laden with 1,000 trillion synapses (Chang et al. 2004). With time the young cells that are not being used are pruned, making the brain more efficient. Pruning takes place again in early adolescence, following overproduction. By the mid-20’s the brain is stable, the pruning process over. This stability involves over 100-500 trillion synapses (Giedd et al, 1999).

We’ve often heard people proclaim we use only a fraction of our brain power; the adult brain has the potential to activate 10 to the millionth power neurons!(Badenoch, 1999) Let’s get busy!!!!

The Glorious Brain-6

Neurons are the basic building blocks of the nervous system.  They transmit information, chemically or electrically, throughout the body.  There are several types of neurons: sensory neuron-they convert external stimuli into internal electrical impulses and transmit this information to the brain and motor neurons-located in the central nervous system, they directly or indirectly control muscles

Neurons have extensions called dentrites that look like spikes extending from the body of the cell.  It is primarily the surface of the dentrite that receives chemical messages from other neurons. Another important extension is the axon that transmits electro-chemical signals to other neurons.

There are 100 billion (more or less) neurons in the adult brain!! Each of these neurons have 7,000-10,000 synaptic connections to other neurons (Bonnie Badenoch, 2008).

Neurotransmitters facilitate communication between neurons by carrying messages that increase (excite) or decrease (inhibit) electrical activity in the neuron.  Thought, mood, behavior and the manner in which we relate to others is greatly influenced by these neurotransmitters.

Reptilian Brain-con’t

As previously stated, the reptilian brain controls our physical response to threat-flight, fight or freeze (these are all reflexes) .  I’ve written often about tracking the sensations in the body; the language of the reptilian brain is sensation. Balance, initiation of movement, breathing, digestion, circulation, sleep, sexuality and action are all governed by this oldest part of the brain.

The reptilian brain-or brainstem-also effects the energy levels of the brain area above it; the limbic and cortex.  It controls arousal, appetite, sexual engagement and sleep. When there is trauma in the body, the reptilian brain stays on ‘on’ and all these systems are impacted.

The Miraculous Somatic Experiencing-8

I recently completed my fifth module of a nine module (3 year) training in Somatic Experiencing.  I am still in awe, still so grateful I found Peter Levine’s tremendous work.  I want to share some of the most striking things I have learned; if you are unfamiliar with Dr. Levine’s work, you might read “Waking The Tiger”.

I particularly love learning about the reptilian brain, also known as the brain stem.  I think of a reptile slowly dragging itself around, always on the look out for danger, constantly scanning the environment.  We, as modern 21st century people, don’t think too much of this part of our selves, being more identified with the thinking, rational cortex.  But it’s there and it still scans and when it senses danger it signals the automatic nervous system.

In previous blogs I wrote about Peter Levine’s model being based on the way animals shake off trauma; if the prey survives the predator, it literally shakes the experience out of its body; the reptilian brain is satisfied all is safe,  and then the trauma free animal continues along its way.  I’ve seen a number of videos of this phenomena; it’s quite striking.  The animal is not left with trauma in its nervous system; humans often are. Remember: what makes an event a trauma is if it’s been locked in the nervous system with no apparent way out. The reptilian brain is thwarted and the autonomic nervous system is is deeply affected.

This effect can show itself in many ways and can effect the sympathetic and/or the parasympathetic systems (please see previous posts).  Next time I’ll write more about this-


The last thing a cell does before it dies is maintain its distinction between inner and outer.  In between the two is a plasma membrane; one of the interesting things about this membrane is that it is not tight and in fact leaks a bit in a controlled way.

The inside of the cell is called the cytoplasm and here things are tightly packed in, divided into sub-cellular compartments. The nucleus is one of these compartments;  you probably remember from high school biology that there is one nucleus in each cell. It is here that we find the chromosomes that contain DNA.

Mitochondriais another sub-cellular compartment. It is the power source of the cell, the part that breathes (uses oxygen to burn food and generate oxygen).  The intake of oxygen is limited to this area for a very good reason-too much oxygen can be lethal and  cause premature aging and cancer.

The Spinal Cord

The  brain stem goes directly into the spinal cord, which is encased in the spinal column and is comprised of 31 vertebrae.  Between each two vertebrae are openings where nerves leave the spinal cord. There are posterior neurons that carry information to the spinal cord; anterior neurons  carry information away.

Afferent nerves, also referred to as sensory, carry sensory information to the spinal cord and brain.  The nerve fibers that carry information away are efferent nerves, also referred to as motor nerves, bring commands to the muscles and organs. The connection between the nervous system and the rest of the body comes from these spinal nerves.  The sole connection between the brain and the rest of the body (with the exception of cranial -neck-nerves )is the brain stem and spinal cord.

In an earlier post, I suggested sitting quietly and doing a slow body scan,  from the feet all the way up to the head. If you’d like, you can add one more element.  After you complete the scan, imagine the spinal cord. Try to visualize it, starting from the brain stem and moving down; imagine all the wonderful energy that passes through the spine-stay with this and try to get a sense of it flowing through your body.

More on The Glorious Brain-5

Our brain’s organization is firstly influenced by genetics and then by experience.  Our experience influences which genes are actually expressed (Siegel, 1999). We constantly have inner and outer experiences that neurons, forming synaptic connections with each other, send to the brain.  They are carried by energy (electrical firing) and information (mental representations that happen with the firing).

All parts of an experience gather in a neural net, that encodes that event (this is how memories are formed).  When one strand of that net is activated by current experience, it is likely the whole net will be activated (this is remembering). Remembering playing ball with your father on a sunny day, you may feel the warmth of this connection, the sensations in your body as you remember throwing the ball, the laughter shared, etc. Thoughts, images, feelings,  body sensations and personal connections tend to flow together. (Badenoch, 2008)