The Nervous System

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There is a lot of information in these details. I do try to keep it simple, but I know that it can still seem complex. To help, I have linked short videos to provide graphic illustration.

The nervous system is a communication highway and decision-making center that work together to process information received from all parts of the body, make decisions about how to respond to that information, and then deliver instruction to targeted body parts to act in certain ways based on those decisions. As simple as it sounds, it involves a great deal of complexity. There is a lot of information here, so take your time.

Neurons (nerve cells)

Here is a 2-minute video that describes a neuron and how it works: https://www.youtube.com/watch?v=6qS83wD29PY

Here is a 2-minute video that describes how one neuron talks to another cell: https://www.youtube.com/watch?v=6qS83wD29PY

Here is some more information that can be helpful in understanding certain medical concerns or language that you may hear from healthcare providers.

The axons referred to in the video are covered by an insulating tissue called myelin. It appears white and is the reasons parts of the brain are referred to as white matter.  The cell bodies are grey and this is the reason you may hear people refer to other parts of the brain as grey matter.

Nerves are either sending or receiving signals. Most of the information a nerve receives is sensory information. Most of the information a nerve sends is motor (movement) information.

The myelin sheath can be become damaged in some health conditions, like multiple sclerosis. As mentioned in the video, the myelin helps the communication signal travel along the axon to the receptor site. If it is damaged, the signal has a harder time traveling and the person's nervous system may not be able to translate the communication properly.

Opioids have an effect on neurotransmitters. Those are the chemicals referred to in the video that cross a tiny divide between the axon and the receptor cell to 'communicate' information to that cell. It is easy to think of the neurochemicals as keys and the receptors sites as keyholes. An opioid attempts to block a keyhole so that a pain key cannot communicate. Unfortunately, the cell is pretty aware of changes. It realizes that it has blocked keyholes and produces new key holes for the pain key. This, then, requires more opioid medication to block the new keyholes. This cycle keeps going until it is no longer safe to continue to increase the opioid dose. As a person tries to come off of the opioids, more and more of those keyholes become unblocked. This includes the original keyholes and the newer keyholes. That is a lot of keyholes receiving pain key signals. The experience can be overwhelming. This is why we want to avoid opioids in the first place and to help step a person off of them while their cells recover to a lower number of keyholes if a person was on opioids. 

Here is a 2-minute video that is more technically correct explaining opioid and the nervous system: https://www.youtube.com/watch?v=NPlNCqBHPnE 

Neurons connect to become long nerve fibers. Nerve fibers bundle together to travel to and from body parts. These bundles of nerves may weave together with other bundles of nerves, unweave, weave together with other bundles, unweave, and eventually unweave to tiny neurons when they reach their specific destinations. There are theories that the weaving and unweaving is part of the reason a person may feel pain in another area of their body then the area that is injured.
 

Nerve healing: 

Nerves inside the spinal cord, in adult mammals, do not spontaneously heal, nor do we have a process to repair them at this time.

A nerve that is damaged outside of the spinal cord has the potential to heal but it is a very, very slow process.  

• A bruised or traumatized nerve that has not been cut can take 6-12 weeks to heal.
• A cut nerve will retract and rest for about a month and then grow at a rate of about 1 mm a day. 
• The nerve may never heal completely.
• If it is cut and not surgically repaired, it may meander on its course, attach incorrectly to another nerve or wrong location, or it may develop lump call a neuroma. 

Spinal cord

Here is a2-minute video that explains the major features of the spinal cord: https://www.youtube.com/watch?v=MM7YNKJj_Lg&list=PLNZqyJnsvdMrr2Zfak7B89soUJo_jzqrH&index=19

The video refers to the brachial plexus and the lumbar plexus. These are two major areas where several bundles of nerves leave the spinal cord and spread out to the arms (brachial plexus) and legs (lumbar plexus). If there is compression of the spinal bones, the vertebrae, in these areas, the ability of these nerves to communicate can be impaired. A person may experience numbness, tingling, weakness, or unusual sensations. They may also have a more difficult time providing an affected part of their body with nutrients, warmth, or cooling as the nerve communication to and from their regulatory systems may be impaired.

Damage to the spinal cord can affect the function of multiple parts of the body whose nerves leave the spinal cord below the level of the damage, depending upon the severity of the damage. 

The brain

The brain is the ‘Grand Central Station’ where information is processed and decisions are made. It has many components, but the big 4 are: the cerebrum, cerebellum, brainstem, and diencphalon. 

The cerebrum is the largest part of the brain taking up most of the space in your skull and is what many people think when imagining the brain. It has right and left sides (hemispheres) which are connected by the corpus callosum which are the ‘white matter’ nerve axons travelling within the brain and connecting the two sides. 

The cerebrum has 4 lobes: frontal, temporal, parietal, and occipital. Each lobe has a set of operations it is primarily responsible for such as executive decision-making, memory, and emotions in the frontal lobe, speech, pain, and touch in the parietal lobe, sensory processing in the temporal lobe, and vision processing, specifically, in the occipital lobe.

Here is a 5-6 minute video that describes an overview of the brain using your hands as a model (pretty cool): https://www.youtube.com/watch?v=FczvTGluHKM

This video talks about the cerebrum, it's lobes, an overview of their actions, and how they connect to the brain stem and spinal cord.

The cerebellum sits under the back end of the cerebrum and looks a bit like a ball of yarn. We know that it is involved with regulating voluntary motor control, balance, and coordination. It may have more functions, though, that we are still learning about. 

Here is a 2-minute video describing the cerebellum: https://www.youtube.com/watch?v=Fir-v6EoZNE

The brainstem is a small area extending from the middle of the brain as it transitions to the spinal cord. It is involved in regulating, heart rate, blood pressure, breathing rate, swallowing, eye movements, hearing, long-term memory, and more. 

Here is a 2-minute video describing the brainstem: https://www.youtube.com/watch?v=T2zjlB4ctu4

The diencephalon is in the center of the brain and houses to thalamus, a ‘traffic cop’ directing sensory information among other important tasks, and the hypothalamus, which works with the pituitary gland to transmit hormonal signals.

Here is a 1-2 minute video illustrating a quick overview of the diencephalon: https://www.youtube.com/watch?v=Na_4HZLvFiM 

The Limbic System

The limbic system is an operational system comprised of several parts of the central brain, including the diencephalon. There is a lot to understand about this system. The basic information to know is that it has a role in emotions, memory, learning, and hormonal regulation, though this is not all. Some parts of the limbic system respond to an experience, such as craving a food or substance that has a strong tie to a good experience (memory) and immediate sense of reward (emotion). Other parts of this system help to regulate that response so that it is not overwhelming and triggering impulsive behaviors.  

Here is a short video that describes the limbic system: https://www.youtube.com/watch?v=LNs9ruzoTmI

The central nervous system is made up of the brain and the spinal cord.

The peripheral nervous system is made up of the nerves outside of the brain and the spinal cord. It can be divided further into the somatic and autonomic nervous systems.

The somatic nervous system is usually thought of the ‘voluntary’ nervous system because you have more conscious control over it. Sensations, including pain signals, travel to the brain and the brain make a conscious choice about how to respond. Despite the ‘voluntary’ nature of this system, it also houses reflex responses, such as removing your hand from a hot stove. 

The autonomic nervous system controls the nerves to your organs. These are nerves that cannot be controlled voluntarily. This system, too, can be divided into the sympathetic (fight-flight-freeze-appease) nervous system and the parasympathetic (rest and digest) nervous system. These sub-systems are involved in the regulation of your digestion, sexual arousal, heart rate, breathing, and blood pressure. The autonomic system can also carry and respond to pain signals.

Here is a 2-minute video describing the divisions of the nervous system: https://www.youtube.com/watch?v=q3OITaAZLNc

To learn more about parasympathetic and sympathetic nervous systems see these 2-minute videos.

Parasympathetic: https://www.youtube.com/watch?v=ADnWvmOlBZk

Sympathetic: https://www.youtube.com/watch?v=FNHRSXe5do8&list=PLNZqyJnsvdMrr2Zfak7B89soUJo_jzqrH&index=37
 

Pain Processing, Mood, and the Nervous System

Several structures in the limbic system and associated cerebral regions are involved in processing pain signals. Many of these same structures are also involved in regulating emotional and motivational responses. As a result, these responses are linked.

• “Changes in the emotional and motivational cues can affect the intensity and degree of pain experience” (section 3, paragraph 1, Yang & Chang, 2019).
• “Fear-avoidance of pain influences physical impairment and is more strongly associated with functional disability than pain severity” (pg 6, Garland, 2012).
   

A special note from my doctoral research related to this:

• Most of those same areas of the brain associated with processing pain signals and mood are also affected by post-traumatic stress disorder (PTSD) and sensory processing disorders (SPD).
• People who experience chronic pain also tend to have experienced significantly traumatic events, including events during childhood. Those who have experienced Adverse Childhood Experiences (ACE factors) tend to be more vulnerable to long-term health challenges.
  NOTE: ACE factors are one side of the coin. We are just delving into resiliency factors. These are important to consider, too.
• When studying the brains of children with SPD, we see beneficial changes to these areas of the brain through sensory-based interventions.
• There is emerging evidence that supports the use of sensory-based interventions to help adults with PTSD as well however this data is very limited and very young.
   

• Manage, manage, manage causes of inflammation, including diabetes and borderline diabetes.
• Use ice to spot treat inflammation and know that you might do better overall in a cool environment compared to a hot one.
• Make relaxation/mindfulness a regular practice to support lower levels of stress-related neurotransmitters.
• Manage your energy so you are not overextending yourself and increasing stress-related neurotransmitters.
• Get restful sleep. It is important for integrating all experiences into their appropriate memory banks in the brain, including the traumatic experiences. It also allows you brain to engage in needed repair processes.
• Manage your mood and relationships to support lower levels of stress-related neurotransmitters.
• Understand that your mood may be influenced by your pain and vice versa. If a provider recommends a medication that you associate with mood management, it may be because it is also associated with pain management.
• There are medications that target nerve function to help reduce pain. There can be side-effects to these so it is best to pair them with other pain management methods to reduce the amount you need.