Peripheral Nervous System Quotes

In truth, there is no such thing as an “intuitive boundary” of a sensory state. That most philosophers take such states as brain-bound is not an intuition, but a prejudice.

Your guts also have about 100 million nerves, more than the number of nerves in your spinal cord or your entire peripheral nervous system.

Self-consciousness is, from a naturalistic point of view (in this case neurobiological), not more than a degree of sophistication of neural processes. The emergence of self-conscious states is not a drastic, extravagant, earth-shaking phenomenon.

The reason I said earlier that the mind is neither the Cartesian, highly intellectualized, cranium-confined firm-and-frozen ego, nor the self-effaced, world-immersed, flowing, field-like non-thingy occurrence, is that even though I was feeling my limbs to be alien to myself, that did not mean that I felt them to be disconnected. Rather, they were intimately connected, yet, merely connected to me, and not phenomenologically proper parts of myself. The mind-world boundary seems to have moved from the skin/environment junction to the innervated/denervated junction within the body. So part of the body has become external to the mind, or ‘de-minded’.

The easiest way for us to recognize this simple concept is to realize that when we experience stress we most often identify it by talking about muscle aches and pains or some type of gastrointestinal or sleep disturbance. These are indicators that the myofascia patterns in the human body have started to constrict and the nervous system has started to elevate. Recognizing that myofascia patterns are intricately linked with the brains neural circuitry as well as the central and peripheral nervous systems, helps us to make sense of the body’s coordinated efforts to protect us when it senses danger.

(...) to think that worms and slugs are neurologically simple is another blunder of contemporary, scientifically uninformed philosophy. To take as an example the current “superstar” nematode worm --superstar, because it was the first multicellular organism to have its genome completely sequenced, by 1998, and is widely used as a model organism-- the 1 mm long Caenorhabditis elegans, it exhibits a nervous system of 302 neurons and a sensorimotor system with very complex connectivity patterns.

Many essential oils are natural analgesics—substances that provide relief from pain by acting on the peripheral and ventral nervous systems. For instance, wintergreen essential oil contains between 85 and 99 percent methyl salicylate, which is the same active ingredient contained in aspirin. Before synthetic pain relievers were introduced in the 1920s, wintergreen and birch were considered to be the best remedies for pain; in fact, Native Americans used both plants before written records were ever kept.

At the present, a plausible nominee for the neural substrate of consciousness is one of the most important neurological discoveries of our time. T h is is that tangle of tiny internuncial neurons called the reticular formation, which has long lain hidden and unsuspected in the brainstem. It extends f rom the top of the spinal cord through the brainstem on up into the thalamus and hypothalamus, attracting collaterals from sensory and motor nerves, almost like a system of wire-tabs on the communication lines that pass near it. But this is not all. It also has direct lines of command to half a dozen major areas of the cortex and probably all the nuclei of the brainstem, as we ll as sending fibers down the spinal cord where it influences the peripheral sensory and motor systems. Its function is to sensitize or “awaken” selected nervous circuits and desensitize others, such that those who pioneered in this work christened it “ t he waking b r a i n

With the most complex brain in the animal kingdom, humans have the most complex nervous system. Its main task is to process sensations. The nervous system has three main parts, working in harmony. One is the peripheral nervous system, running through organs and muscles, such as the eyes, ears, and limbs. The second part is the autonomic nervous system, controlling involuntary functions of heart rate, breathing, digestion, and reproduction. The third part is the central nervous system (CNS), consisting of countless neurons, a spinal cord, and a brain.

1. that the emergence of the nervous system was an indispensable enabler of life in elaborate multicellular organisms; the nervous system has been a servant of whole-organism homeostasis, although its cells also depend on that same homeostasis process for its own survival; this integrated mutuality is most often overlooked in discussions of behavior and cognition; 2. that the nervous system is part of the organism it serves, specifically a part of its body, and that it holds close interactions with that body; that these interactions are of an entirely different nature from those that the nervous system holds with the environment that surrounds the organism; the particularity of this privileged relationship also tends to be overlooked; I will say more on this critical issue in part II; 3. that the extraordinary emergence of the nervous system opened the way for neurally mediated homeostasis—an addition to the chemical/visceral variety; later, after the development of conscious minds capable of feeling and creative intelligence, the way was open for the creation, in the social and cultural space, of complex responses whose existence began as homeostatically inspired but later transcended homeostatic needs and gained considerable autonomy; therein the beginning but not the middle or the end of our cultural lives; even at the highest levels of sociocultural creation, there are vestiges of simple life-related processes present in the most humble exemplars of living organisms, namely, bacteria; 4. that several complex functions of the higher nervous system have their functional roots in simpler operations of the lower devices of the system itself; for this reason, for example, it has not been productive to first look for the grounding of feeling and consciousness in the operations of the cerebral cortex; instead, as discussed in part II, the operation of brain-stem nuclei and of the peripheral nervous system offers better opportunities to identify precursors to feeling and consciousness.

The numbers of sensory endings and motor neurons in the periphery have multiplied considerably as fishes and birds and mammals developed, producing sharper and more complete sensory impressions, and making possible a finer and finer control of the musculature. But the essential features of the peripheral system have not greatly altered. In them the basic rudiments of the primitive nervous system are still preserved, “a mechanism by which a muscular movement can be initiated by some change in peripheral sensation, say, an object touching the skin.” What has changed enormously is the relationship between these ancient sensory and motor elements. In the hydra sensation and motor response were united in a single cell; in the jellyfish these two functions were divided into two specialized cells; and in the flatworm an intermediate network of cells was placed between them. The two more primitive elements have since become increasingly separated as the internuncial net has increased in bulk and sophistication, and their synaptic connections, once direct, have been distanced by more and more modifying circuits.

As nervous systems developed, they acquired an elaborate network of peripheral probes—the peripheral nerves that are distributed to every parcel of the body’s interior and to its entire surface, as well as to specialized sensory devices that enable seeing, hearing, touching, smelling, and tasting. Nervous systems also acquired an elaborate collection of aggregated central processors in the central nervous system, conventionally called the brain.10 The latter includes (1) the spinal cord; (2) the brain stem and the closely related hypothalamus; (3) the cerebellum; (4) a number of large nuclei located above brain-stem level—in the thalamus, basal ganglia, and basal forebrain; and (5) the cerebral cortex, the most modern and sophisticated component of the system. These central processors manage learning and memory storage of signals of every possible sort and also manage the integration of these signals; they coordinate the execution of complex responses to inner states and incoming stimuli—a critical operation that includes drives, motivations, and emotions proper; and they manage the process of image manipulation that we otherwise know as thinking, imagining, reasoning, and decision making. Last, they manage the conversion of images and of their sequences into symbols and eventually into languages—coded sounds and gestures whose combinations can signify any object, quality, or action, and whose linkage is governed by a set of rules called grammar. Equipped with language, organisms can generate continuous translations of nonverbal to verbal items and build dual-track narratives of such items.

Efferent impulses may be conducted along one of two major pathways of motor neurons as they pass from the brain through the cord and out to the muscles, and together these longitudinal pathways provide for the convergence of the influences from all levels of the central nervous system upon the motor units. The fastest of these descending routes is the direct corticospinal pathway. As the name suggests, the cell bodies of this path are in the cortex, and they send their long axons directly through the brain and down the spinal cord without any interruptions. These axons do not form any synapses until they reach their corresponding motor neurons in the cord, and thus they form direct connections between specific cells in the motor cortex and specific motor neurons at each level of the cord, making one-to-one relationships between cortical cells and peripheral motor units. This pathway bypasses most of the intermediate circuitry of the lower brain and the spinal cord. This gives it the advantage of speedy transmission. The axons which are bundled together within it maintain a constant spatial relationship throughout their length, faithfully reflecting the spatial relationships of the cell bodies in the cortex. The longest axons, reaching all the way to the end of the cord, lie the closest to the center of the cord, and the progressively shorter axons which synapse to motor neurons in progressively higher segments, are carefully laid down in layers progressively far from the center of the cord, so that a “map” of skeletal muscle relationships is projected onto the motor cortex. This gives a high degree of specificity to this direct corticospinal tract. This direct pathway is the mediator of fine, intricate movements, which require close conscious attention and constantly refined adjustment. When it is severed, actions become clumsier, because the sharp edge of delicate conscious control is missing.

These descending sensory pathways originate in the cortex, and their influence can either inhibit or facilitate the sensory input from any area of the body, greatly amplify or suppress altogether any given sensation. Sensory activity within the central nervous system is a Janus head, a two-way stream; signals originating in the brain have just as much to do with conscious sensation as do actual stimulations of the peripheral nerve endings. In fact, it is the descending paths which determine the sensitivity of any particular ascending pathway. The wide varieties of sexual response—among different individuals and within the same individual at different times—provide us with a clear example of this centrifugal influence upon incoming sensations: Depending upon past experiences and the present situation, the same stimulation of the genitals can produce intense ecstasy, bland and neutral sensations, or extreme discomfort. Orgasm can be immediate, or deferred indefinitely. And the imagination alone can produce constant engorgement, utter impotence, and all the degrees of arousal in between. The descending paths can color all kinds of sensory input to this degree. These pathways allow the mind to determine the active threshold for different sensory signals, and make it possible to focus attention upon a single source of input in the midst of many. It is difficult to imagine what practical use our sensory apparatus would be to us without such a mechanism. We would have no way of selecting a voice from all the other sounds around us, of locating specific objects within the swirl of visual impressions, or of retiring from our senses for contemplation and sleep. This centrifugal principle of selectivity is as vital to our appropriate responses to the world as is stimulation itself.

It is important to remember that in its simplest form the nervous system is merely a mechanism by which a muscular movement can be initiated by some change in the peripheral sensation, say, an object touching the skin.

There is another way of separating the whole system into major divisions, divisions which are not as visually obvious as peripheral and central, but which in some ways more accurately represent actual functional distinctions. Roughly half of our neurons have their dendrites reaching out towards the surfaces of our organisms, and their axons reaching in towards the core. This means that they propagate their action potentials in an inward—centripetal—direction. The other half are arranged with their dendrites reaching in towards the core and their axons reaching out towards the periphery; these neurons send their action potentials in an outward—centrifugal—direction. The pathways created by these differently oriented neurons do not stop at the threshold of the central nervous system; both can be traced from the periphery to the spinal cord, throughout the cord’s length, through the brainstem and the hypothalamus, and finally to the literal summit of the brain, the sensory and motor cortexes. This division is based, then, not on the separation of these different anatomical structures, but upon the direction of action potential flow through those structures and the specific pathways they take.

It is really just as accurate to say that it has been the increasingly numerous and complex sensations associated with locomotion that has led to the development of the brain, as it is to state the case the other way around. As with all matter, usage dictates shape, specific function produces specific form. Thus as the animal kingdom has moved forward from jellyfish to worms to vertebrates, new behavior patterns have bodied forth new neural structures and circuits, just as surely as new neural mechanisms have opened up new modes of behavior. Once such a pattern has been established, the increasing sensory experience which arises from the assumption of a terrestrial existence is associated with further increases in the size and complexity of the brain, so that more complex behavior patterns are possible. Thus in man the assumption of the erect posture and the freeing of the upper limb from its supporting functions, with the consequent development of the hand as a potent new sensory organ, may well have played a significant part in the growth of the human nervous system to its present complexity.9 And note well: In this development, it has been the kind and the amount of sensory input which have been major factors in these profound changes in the structure and function of the central and peripheral nervous systems. Deep neuromuscular patterns most certainly are, and always have been, wide open to the influences of specific qualities and quantities of touch. In this context, it does not seem at all impossible that effective bodywork could foster new levels of awareness, new patterns of response, and even new neural conditions that would influence all future responses in an individual. The entire developmental history of the centralization and encephalization of the human nervous system is evidence of the potent organizing powers of touch.

The lowest level of this modifying intermediate network is the spinal cord. The cord still possesses many features that were first developed in the segmented earthworm. It is largely made up of neurons completely contained within it, which form bridges between the sensory and motor elements throughout the whole body. Each peripheral nerve trunk still innervates a specific segment of the body, and still joins the cord at a specific level, creating a ganglion. Sensory signals entering into a single segment may be processed by its own ganglion, and cause localized motor response within the segment; or the signals may pass to adjacent segments, or be carried even further up or down the line, involving more ganglia in a more widely distributed response. In this way, the cord can monitor a large number of sensorimotor reactions without having to send signals all the way up to the brain. Thus stereotyped responses can be made without our having to “think” about them on a conscious level. Most of these localized and segmentally patterned responses are not the result of experience or training, but of genetically consistent wiring patterns in the internuncial network of the cord itself. These basic wiring patterns unfold in the foetus during the “mapping” process of the nervous system, and they have been pre-established by millions of years of development and usage. The spinal cord can be surgically sectioned from the higher regions of the internuncial net, and the experimental animal kept alive, so that we can isolate the range of responses that are primarily controlled by these cord reflexes. Almost all segmentally localized responses can be elicited, such as the knee jerk caused by tapping the tendon below the knee cap, or the elbow jerk caused by tapping the bicep tendon. These simple responses can also be spread into other segments, so that a painful prick on a limb causes the whole body to jerk away in a general withdrawal reflex. The bladder and rectum can be evacuated. A skin irritation elicits scratching, and the disturbance can be accurately located with a paw. Some of the basic postural and locomotive reflex patterns seem to reside in the wiring of the cord as well. If an animal with only its cord intact is assisted in getting up, it can remain standing on its own. The sensory signals from the pressure on the bottoms of the feet are evidently enough to trigger postural contractions throughout the body and hold the animal in the stance typical of its species. And if the animal is suspended with its legs dangling down, they will spontaneously initiate walking or running movements, indicating that the fundamental sequential arrangements of the basic reflexes necessary for walking are in the cord also. All of these localized and intersegmental responses are rapid and automatic, follow specific routes through the spinal circuitry, and elicit stereotyped patterns of muscular response. Most of them appear to consistently use the same neurons, synapses, and motor units every time they are initiated.

The dorsal root ganglia are located all along the spinal column, at the level of each vertebra, one on each side of the spine, linking the body’s periphery with the spinal cord, that is, connecting peripheral nerve fibers to the central nervous system. This is one of the routes for conveying sensory signals from limbs and torso to the central nervous system. Information about the face is also transmitted centrally by two large but lonely ganglia: the trigeminal ganglia, one on each side of the brain stem.

This finding means that while the neurons themselves work to convey peripheral signals to the central nervous system, they do not do so alone. On the contrary, they are assisted; they are modulated directly by molecules circulating in the blood. The signals that, for example, help generate the pain from a wound are conveyed to precisely such dorsal root ganglia.20 Given the arrangement I just described, the signals are thus not “purely” neural. The body has its say on the process, directly, via influential chemical molecules circulating in the blood. The same influence can be exerted higher up in the system, at the level of the brain stem and the cerebral cortices. The denuding of the blood-brain barrier is one mechanism for blending body and brain. In fact, permeability may turn out to be a fairly general feature of peripheral ganglia.21 These facts need to be factored in the scholarship of feelings.

Anxiety is a fact of life! Everyone experiences it. It began in our cave-dweller days as a fight-or-flight response. Think of it this way: If you were walking through the woods and you ran into a bear, it would be normal for your body to activate the fight-or-flight response. Your heart would race, your muscles would tense up, your pupils would dilate, you would breathe more rapidly. The same thing would happen today if you were walking down the street and ran into a mugger. There is a simple, scientific explanation of this response: Your mind and body are preparing to protect you—whether you can feel it happening or not. Let us briefly examine this process. Your nervous system is divided into two basic parts: The voluntary nervous system controls actions that require thought, such as using the different parts of your body to drive a car; the autonomic nervous system, among its many functions, suspends all nonessential activity of the body and increases the physiological activity needed to confront the situation—either by fighting or by fleeing the external threat. Here is what it is responsible for: -increase muscle tension -accelerated heartbeat -rapid breathing -constriction of peripheral blood vessels (this is what causes cold hands) -dilation of the pupils -suspension of the digestive process -dry mouth -a voiding of bladder and bowels In addition, the fight-or-flight response causes a marked increase in the flow of adrenaline through the bloodstream and therefore added strength.

YOGI NERVE REVITALIZING BREATH This is an exercise practiced by virtually all yogis, who generally consider it one of the strongest nerve stimulants. It stimulates the central and peripheral nervous systems, and develops nerve force, energy, and vitality. It also brings stimulating pressure on several important nerve plexi that are associated with various chakras, which stimulates the entire nervous system and sends increased peripheral nerve force to all parts of the body. 1. Stand erect, inhale a Complete Breath, and retain it. 2. Extend your arms in front of you loosely, in a relaxed way. 3. Slowly move your hands back to your shoulders, as you squeeze your fists increasingly hard. 4. With your fists clenched very tightly, push them out and draw them back rapidly, several times. 5. Exhale vigorously through the mouth.

brain and other nerve-related problems such as headaches from concussions, vascular dementia (dementia caused by blood vessel problems in the brain), migraines, Bell’s palsy (a paralysis of the facial nerve), and tinnitus (ringing of the ears). He emphasized he was influenced by research that had been done in Israel on light therapy and the brain. Dr. Shimon Rochkind, a neurosurgeon at Tel Aviv University, originally pioneered work using lasers to treat injuries in the peripheral nervous system, that is, all the nerves in the body except those in the brain and spinal cord. Injury to peripheral nerves can lead to problems sensing or moving.

Typically, one of the arguments against the ethicalness of chemical castration is that it affects the very core of personhood, part of which is sexual drive and sexual fantasizing, by indirectly acting on the CNS (…) But, I think, an equally good argument could be that it interferes with basic homeostatic processes of the organism, regulated by the autonomic PNS and the endocrine system. Maybe the public tends to agree with chemical castration of sexual offenders, especially of pedophiles, not only because of the terrible acts they have committed, but also because there is a hidden prejudice that the “real or genuine person” of such offenders is a mind that has been captured by hormones, and that there is nothing wrong in “killing off these hormones and liberate the person from their vicious influence” (…) I say it is a prejudice because part of what it means to be a mentally healthy and well adapted individual involves a huge influence of the hormonal component, not only testosterone, but all other hormones, and, as a matter of fact, sexual offenders do not have abnormally high levels of free testosterone.

Synapsin Synapsin is a major immunoreactive protein found in most neurons of the central and peripheral nervous systems. It is a brain protein involved in the regulation of neurotransmitters (brain hormones). These antibodies to your brain cause demyelinating diseases (like MS) and numbness and tingling anywhere in your body. Synapsin also will inhibit the release of neurotransmitters and can cause lupus as well as mood disorders and depression.

Findings have become common on brain-like processes outside of the skull. The conductive structure inside the heart, like pacemaker cells, which organizes the heartbeat, can be known as the brain of the heart, just as the intestine's brain is the ganglion cells in the gut. Conduction system independence is shown when a transplanted heart continues to beat even though the nerves that connected it to the central and peripheral nervous systems of the donor have been severed. The interaction between the independent processing of the heart and that of the brain is complex and not fully understood. The trillions of bacteria that outnumber the cells of the body by ten to one are even more enigmatic, residing mostly within the digestive tract but also on the skin and in the brain and other organs. We think of these bacteria as pests, but these micro-organisms were simply introduced in vast stretches along the double helix of human DNA over eons. The consequences are immense and essentially uncharted for what we call "being alive" The bacterial part of the body, taken as a whole, is called the microbiome. It is not sitting on the skin or in the gut passively, nor is it invading the body. Actually, the microbiota is the barrier between "in here" and "out there," containing DNA, antibodies, and chemical signaling that allows the brain to do the same stuff. There is no clear role of the microbial DNA that is incorporated into our genomes, but at least this is ancestral material that we have assimilated as our own. More suggestively, this once-foreign DNA in all higher life-forms may be the swapping mechanism for genes. These discoveries demonstrate that our intelligence extends to the whole of ecology. Everywhere mentality has a physical basis. Any attempt at isolating it in the skull comes up against serious objections. Instead of treating cynicism with unbounded consciousness, we need to see that every perception is unbounded. By going beyond the illusory boundaries of the disconnected body, you cannot see, hear or touch anything in the universe. Watching a sunset is like watching yourself, actually.

In chronic anemia, diminished oxygen-carrying capacity is compensated by an increased cardiac output, recruitment of additional capillaries, redistribution of blood flow (from peripheral tissue to cardiac and central nervous system), and increased production of 2,3-diphosphoglycerate (2,3-DPG) by RBCs.