<p></p><h2><a>The Central Nervous System (CNS)</a></h2><p>The central nervous system includes the brain (contained within the skull), which weighs 1.3–1.4 kg in humans, and also the spinal cord, which extends into the vertebral canal. The brain is grossly divided into the brainstem, cerebellum, and cerebrum. The cerebrum is further divided into the basal ganglia, limbic system, and neocortex.</p><img src="@@PLUGINFILE@@/CNS.jpg" alt="Central Nervous System" width="424" height="839"><p></p><p></p><p><i>Figure 2a: The major components of the Central Nervous System</i></p><p></p><h2><a></a><a>Spinal cord</a></h2><p>The spinal cord descends from the brainstem down through the shielded tunnel of the vertebrae,&nbsp; and transmits information from the body to the brain and from the brain to the body. Thus, the central nervous system is composed of nerves the are rooted to both the surface of the brain, as well as to the spinal cord. Most nerves are peripheral nerves, which extend and branch toward the surface of the body.</p><img src="@@PLUGINFILE@@/Spinal%20Cord.jpg" alt="Spinal Cord Anatomy" width="372" height="471"><p></p><p><i>Figure 2b: Anatomy of the Spinal Cord</i></p><p><i><img src="@@PLUGINFILE@@/Peripheral%20Nervous%20System.jpg" alt="Peripheral Nervous System" width="723" height="917"><br></i></p><div>

<p>The brain grows, layer upon layer, like an onion. Brain cells generating grab onto a guide wire,
which is a glial
fiber, a glial highway, with the nucleus
in the back. No other kind&nbsp;<span style="font-size: 1rem;">of cell has to do this. Neurons travel in waves,
which scientists call migration.
&nbsp;In terms of the distances relative to their size, they are making an odyssey, without &nbsp;mistakes telling
them where to go in the brain.</span></p><p>of cell has to do this. Neurons travel in waves,
which scientists call migration.
&nbsp;In terms of the distances relative to their size, they are making an odyssey, without &nbsp;mistakes telling
them where to go in the brain.</p><p>Here is a cool video made by the Pasterkamp lab, outlining the signaling events and molecular mechanisms involved in the formation of neuronal connections during development.<br></p><p>&nbsp;<video controls="true"><source src="<iframe width=&quot;560&quot; height=&quot;315&quot; src=&quot;https://www.youtube.com/embed/ZWACm6BkDVo&quot; frameborder=&quot;0&quot; allow=&quot;accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture&quot; allowfullscreen></iframe>">&lt;iframe width="560" height="315" src="https://www.youtube.com/embed/ZWACm6BkDVo" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen&gt;&lt;/iframe&gt;</video>&nbsp;<br></p><p></p><h2>The Triune Brain Theory</h2><br><p></p><p></p><p>The triune brain
was first described by Maclean in 1990, as consisting of three layers that depict
our evolution individually as a species. &nbsp;The first layer is the reptilian
brain (its core), responsible for activation, arousal,
homeostasis, and reproductive drives. This is the dinosaur brain, the same brain that has been around for 2,000,000
years. The reticular formation at
the conjunction &nbsp;of the thalamus and the brainstem oscillates at 2Hz (delta) {Thatcher, 2015). At&nbsp;<span style="font-size: 1rem;">birth, this structure &nbsp;is already
in place and fully functional.</span></p><img src="@@PLUGINFILE@@/triune%20brain.jpg" alt="Triune Brain" width="790" height="514" class="img-responsive atto_image_button_text-bottom"><br><p></p><p></p><p>The reptilian
brain controls the body’s most basic, involuntary actions, like heartbeat,
breathing, body temperature regulation, and balance. It consists of the
brainstem and the cerebellum (which joins the limbic thalamus by the reticular
activating system). The cerebellum is the most densely packed area;
surprisingly, this is where 80% of the brain’s neurons live (Herculano-Houzel,
2010). Used mostly for gross movements and balance, parts of the cerebellum are
involved in the coordination of language, memory, and&nbsp;<span style="font-size: 1rem;">reasoning (Schmahmann, 1997). Interestingly, new literature
suggests that the cerebellum plays a significant role in regulating the
cerebrum, both via white matter (sub-cortically) and via grey&nbsp;</span><span style="font-size: 1rem;">matter (cortically) (Schmahmann, 1997, 1998, 2000; Teicher,
Anderson, &amp; Polcari, 2012). This is the part of the brain that is cradled
by the hand of a loving mother, and the part of the brain that also
unconsciously senses the absence of her hand, in situations of neglect (Fisher,
2014, p. 23).</span></p>

<p><br></p><h2><a name="_Toc28940388"></a><a name="_Toc3535195">Brainstem</a></h2>

<p>The brainstem is
responsible for carrying all information from the body to the cerebrum and
cerebellum (hindbrain) and from the brain to the body. The pathways ascending
from the body to the brain are the sensory pathways and communicate to your
brain that which is going on with the body (pain, hunger, desires, temperature,
sensations, etc). The descending pathways move from the brain to the body. The
last job of the brain stem is its regulation of various systems, such as your
cardiovascular system, respiratory system, pain sensitivity controls, as well
as alertness, and consciousness.</p>

<p>The brainstem plays a
primary role in conduit functions. That is, all information related from the
body to the cerebrum and cerebellum and vice versa, must traverse the brain
stem. The ascending pathways coming from the body to the brain are the sensory
pathways. Descending tracts are upper motor neurons destined to synapses on
lower motor neurons. The brain stem also has integrative functions. It is
involved in cardiovascular system control, respiratory control, pain
sensitivity control, alertness, and consciousness.</p>Here is a short video on the anatomy of the brainstem.<p></p><p>&nbsp;<video controls="true"><source src="<iframe width=&quot;560&quot; height=&quot;315&quot; src=&quot;https://www.youtube.com/embed/T2zjlB4ctu4&quot; frameborder=&quot;0&quot; allow=&quot;accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture&quot; allowfullscreen></iframe>">&lt;iframe width="560" height="315" src="https://www.youtube.com/embed/T2zjlB4ctu4" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen&gt;&lt;/iframe&gt;</video>&nbsp;<br></p><p></p><h2><a name="_Toc28940390">THE LIMBIC SYSTEM</a></h2>

<p>After the reptilian brain is formed,
the next layer,
the paleomammalian &nbsp;brain, better known as the limbic system,
is primed and ready to be further &nbsp;developed by early life experiences. This area is largely
responsible for the functions&nbsp; of memory, learning,
and emotion. This second layer is responsible for basic autonomic
functioning, as well as reflexes, and basic
survival (DeRidder, 2014).
The proliferation of the limbic system created higher
frequencies, such as theta and alpha. The limbic
structures include the amygdala, hippocampus, thalamus, hypothalamus, basal
ganglia, and cingulate
gyrus. These limbic
structures are wrapped
in the cerebral cortex, which is the outermost
&nbsp;and third &nbsp;layer
of the brain.</p><p><img src="@@PLUGINFILE@@/Limbic%20System.png" alt="Limbic System" width="258" height="179" class="atto_image_button_text-bottom"><br></p>

<p>From an
evolutionary perspective, the reptilian brain is fully functional at birth and
the second layer—the limbic system—is prepared for the organizational
experiences of early life. The neuronal development of the brain’s first and
second layers are virtually complete at birth; the branching of dendrites that
occurs thereafter is dubbed “wiring,” since the growth of neurons and dendrites
resembles wires (Seung, 2012). The wiring and creation of oligodendrocytes
(glia cells </p>

<p><br>
responsible for myelination) now occurs from the limbic structures into the
cortex. The self-reliance of the brain circuits has increased as we have
evolved, and have moved to higher levels in the brain, ones that have less and
less contact with sensory inputs.</p>

<p>Most of our
significant early emotional and intellectual experiences, those that shape our
later perceptions and reactions, occur when the limbic and reptilian structures
are in dominance (Cozolino, 2002, p. 9). That is to say, many of our
social-emotional reactions and behaviors are literally programmed beneath the
surface of our consciousness. Indeed, empirical evidence suggests that
processing emotion can occur without conscious awareness (Balconi &amp;
Lucchiari, 2008; Bunce, Bernat, Wong, &amp; Shevrin, 1999; LeDoux, 1998a). </p>

<p>&nbsp;</p><h3><a name="_Toc28940391">Neuroanatomy of the Limbic System</a></h3><p><b style="color: rgb(82, 96, 105); font-size: 1rem; font-family: &quot;Open Sans&quot;, sans-serif;">&nbsp;</b><span style="color: rgb(82, 96, 105); font-size: 1rem; font-family: &quot;Open Sans&quot;, sans-serif;">The amygdala is located
within the temporal</span>&nbsp;lobes. It is essential to the experience of fear responses and its primary
function is arousal.
This complex structure &nbsp;controls the autonomic responses associated with fear; emotional responses
{i.e. rage and anger) and Hormonal
Secretions. The right-side amygdala is devoted
to survival and reacts to threats, both real and perceived. The amygdala is an
almond shaped mass of nuclei located deep within the temporal lobes, medial to the hypothalamus and adjacent to the hippocampus. This area of the brain is
prone to kindling, which is essentially repetitive &nbsp;neuronal firing
that gives rise to high
amplitudes, until the pattern collapses. Each kindling lowers
the threshold of the future
ones, making them more likely.</p><img src="@@PLUGINFILE@@/amygdala.png" alt="amygdala" width="456" height="585" class="img-responsive atto_image_button_text-bottom">Check out this video of the Amygdala:<br><p></p><p>&nbsp;<video controls="true"><source src="<iframe width=&quot;560&quot; height=&quot;315&quot; src=&quot;https://www.youtube.com/embed/JVvMSwsOXPw&quot; frameborder=&quot;0&quot; allow=&quot;accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture&quot; allowfullscreen></iframe>">&lt;iframe width="560" height="315" src="https://www.youtube.com/embed/JVvMSwsOXPw" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen&gt;&lt;/iframe&gt;</video>&nbsp;<br></p><p></p><h3><br></h3>

<h4>Basal Ganglia</h4>

<p>The Basal Ganglia are collections of nerve cells deep within
the brain. Most of the basal ganglia are concerned with movement, though parts are devoted to language, thought, motivation &nbsp;and emotion. They include the caudate nucleus,
the putamen, the thalamus, the globus pallidus,
and the tail of the caudate nucleus.</p><p><img src="@@PLUGINFILE@@/Basal%20Ganglia.png" alt="Basal Ganglia" width="574" height="402" class="img-responsive atto_image_button_text-bottom"><br></p><div>

<h4>Diencephalon</h4><p>This is the division
of the forebrain, the forward &nbsp;most
portion &nbsp;of the brain in vertebrates, which controls temperature, reproductive functions, eating, sleeping, and the display
of emotions. The diencephalon includes
the thalamus, hypothalamus, posterior portion of
the pituitary &nbsp;gland and the pineal gland. The third
ventricle is enclosed
by the diencephalon.<span style="font-size: 1rem;">&nbsp;</span></p><p><span style="font-size: 1rem;"><img src="@@PLUGINFILE@@/diencephalon.jpg" alt="diencephalon" width="500" height="376" class="img-responsive atto_image_button_text-bottom"><br></span></p>

<h4>Hypothalamus</h4><p>The hypothalamus links the nervous
system to the endocrine system via the pituitary
&nbsp;gland (hypophysis). The hypothalamus controls
body temperature, hunger, thirst, fatigue, anger, and circadian
cycles. The hypothalamus is located below the thalamus,
just above the brain stem. The hypothalamus is responsible for certain metabolic processes and other activities of the autonomic nervous system. It synthesizes and secretes neurohormones, often
called hypothalamic-releasing &nbsp;hormones, and these in turn stimulate or inhibit the secretion of pituitary
&nbsp;hormones.</p>

<p>&nbsp;<img src="@@PLUGINFILE@@/hypothtrlamus.jpg" alt="hypothalamus" width="600" height="300" class="img-responsive atto_image_button_text-bottom"></p><p>For your viewing pleasure, a short video on the hypothalamus:</p><p>&nbsp;<video controls="true"><source src="<iframe width=&quot;560&quot; height=&quot;315&quot; src=&quot;https://www.youtube.com/embed/TVhm2rBGhB0&quot; frameborder=&quot;0&quot; allow=&quot;accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture&quot; allowfullscreen></iframe>">&lt;iframe width="560" height="315" src="https://www.youtube.com/embed/TVhm2rBGhB0" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen&gt;&lt;/iframe&gt;</video>&nbsp;<br></p>

<h4>Hippocampus&nbsp;</h4><p>&nbsp;The hippocampus is a part of the forebrain, located
in the medial temporal lobe. It belongs to the limbic system and plays major roles in short term memory
and spatial navigation.</p>

<p>&nbsp;Here's a video on the hippocampus:&nbsp;&nbsp;<video controls="true"><source src="<iframe width=&quot;560&quot; height=&quot;315&quot; src=&quot;https://www.youtube.com/embed/5EyaGR8GGhs&quot; frameborder=&quot;0&quot; allow=&quot;accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture&quot; allowfullscreen></iframe>">&lt;iframe width="560" height="315" src="https://www.youtube.com/embed/5EyaGR8GGhs" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen&gt;&lt;/iframe&gt;</video>&nbsp;</p>

<h4>Pituitary</h4><p>The &nbsp;pituitary is a small pea-size master gland of the endocrine
&nbsp;system that sits in a
bony depression beneath
the hypothalamus. Its job deals with directing chemical changes to regulate
the entire organic
system.</p><p>Here is a short video on the pituitary and the hypothalamus</p><p>&nbsp;<video controls="true"><source src="<iframe width=&quot;560&quot; height=&quot;315&quot; src=&quot;https://www.youtube.com/embed/TVhm2rBGhB0&quot; frameborder=&quot;0&quot; allow=&quot;accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture&quot; allowfullscreen></iframe>">&lt;iframe width="560" height="315" src="https://www.youtube.com/embed/TVhm2rBGhB0" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen&gt;&lt;/iframe&gt;</video>&nbsp;<br></p>

<p>&nbsp;</p>

<h4>Reticular
formation</h4><p>The reticular &nbsp;formation (also known as the reticular activating system) is at the core of the brainstem
&nbsp;and plays a
vital role in sleep, emotion, breathing, blood pressure, and heart rate.&nbsp;<span style="font-size: 1rem;">The reticular formation oscillates at 2 hz and is the dinosaur
brain, roughly </span><i style="font-size: 1rem;">2,000,000 </i><span style="font-size: 1rem;">years old in its evolutionary trajectory,
is the same structure &nbsp;that we have.</span></p><p><span style="font-size: 1rem;"><img src="@@PLUGINFILE@@/RAS.jpg" alt="RAS" width="600" height="600" class="atto_image_button_text-bottom"><br></span></p></div>

<h4>Thalamus</h4><p>The thalamus
is an egg-shaped structure &nbsp;deep within the brain that acts as a relay station, receiving information from all senses (except
olfactory) &nbsp;processing the data and passing it between the spinal <i>cord,</i><i> </i>the medulla oblongata and the cerebral
cortex. It relays sensory signals like motor &nbsp;signals to the <i>cortex, </i>and it also plays in the regulation of
sleep and arousal states. It is the beginning of the brain's
formation at 5 weeks in utero.</p><p><span style="font-size: 1rem;">The thalamus is composed of the thalamic nuclei, which aids in the processing of various stimuli. Here is a general video of the thalamus:</span></p><p><span style="font-size: 1rem;">&nbsp;<video controls="true"><source src="<iframe width=&quot;560&quot; height=&quot;315&quot; src=&quot;https://www.youtube.com/embed/IF8_82e9RmQ&quot; frameborder=&quot;0&quot; allow=&quot;accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture&quot; allowfullscreen></iframe>">&lt;iframe width="560" height="315" src="https://www.youtube.com/embed/IF8_82e9RmQ" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen&gt;&lt;/iframe&gt;</video>&nbsp;<br></span></p><p>And here is a video on the specificities of the various parts of the thalamic nuclei:</p><p>&nbsp;<video controls="true"><source src="<iframe width=&quot;560&quot; height=&quot;315&quot; src=&quot;https://www.youtube.com/embed/H-oCTE41Evg&quot; frameborder=&quot;0&quot; allow=&quot;accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture&quot; allowfullscreen></iframe>">&lt;iframe width="560" height="315" src="https://www.youtube.com/embed/H-oCTE41Evg" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen&gt;&lt;/iframe&gt;</video>&nbsp;<br></p><p>Here is a general video of the Basal Ganglia</p><p>&nbsp;<video controls="true"><source src="<iframe width=&quot;560&quot; height=&quot;315&quot; src=&quot;https://www.youtube.com/embed/OD2KPSGZ1No&quot; frameborder=&quot;0&quot; allow=&quot;accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture&quot; allowfullscreen></iframe>">&lt;iframe width="560" height="315" src="https://www.youtube.com/embed/OD2KPSGZ1No" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen&gt;&lt;/iframe&gt;</video>&nbsp;<br></p>

<h4>Caudate Nucleus</h4><p>The caudate nucleus is one of the structures that makes up
the dorsal striatum of the basal ganglia. This part of the brain&nbsp;plays
important roles in various other nonmotor functions as well, including&nbsp;<a href="https://en.wikipedia.org/wiki/Procedural_learning" title="Procedural learning">procedural learning</a>, <a href="https://en.wikipedia.org/wiki/Associative_learning" title="Associative learning">associative learning</a>&nbsp;and&nbsp;<a href="https://en.wikipedia.org/wiki/Inhibitory_control" title="Inhibitory control">inhibitory control</a>&nbsp;of action, &nbsp;among
other functions. The caudate is also one of the brain structures which compose
the&nbsp;<a href="https://en.wikipedia.org/wiki/Reward_system" title="Reward system">reward system</a>&nbsp;and functions as part of
the&nbsp;<a href="https://en.wikipedia.org/wiki/Prefrontal_cortex" title="Prefrontal cortex">cortico</a>–<a href="https://en.wikipedia.org/wiki/Basal_ganglia" title="Basal ganglia">basal ganglia</a>–<a href="https://en.wikipedia.org/wiki/Thalamus" title="Thalamus">thalamic</a>&nbsp;loop.</p>

<p>And here is a little video of the Caudate Nucleus (It's a little funky, but helps explain anatomy):</p><p>&nbsp;<video controls="true"><source src="<iframe width=&quot;560&quot; height=&quot;315&quot; src=&quot;https://www.youtube.com/embed/GcB5_gXka2g&quot; frameborder=&quot;0&quot; allow=&quot;accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture&quot; allowfullscreen></iframe>">&lt;iframe width="560" height="315" src="https://www.youtube.com/embed/GcB5_gXka2g" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen&gt;&lt;/iframe&gt;</video>&nbsp;<br></p>

<p>&nbsp;</p>

<h4><a name="_Toc525053947">Parahippocampal Gyrus</a></h4><p><a name="_Hlk525136529">The parahippocampal gyrus is a region which is responsible for
many functions, most notably for short-term working memory. The left-hand side
is related to more verbal processes than the right, the right hand side has
more to do with forming associations. This area of the brain has much to do
with the encoding and recognition of scenes; this area of the brain becomes
active when taking in topographical scenes (images of cities, landscapes, and
rooms—images of places).&nbsp; Furthermore,
this area is involved in procedural memory consolidation, recognition, and
recall. It is a component part of the networks for autobiographical memory,
embarrassment, and regret.</a> </p><img src="@@PLUGINFILE@@/Parahippocampal%20gyrus.jpg" alt="PArahippocampal gyrus" width="1600" height="1131" class="img-responsive atto_image_button_text-bottom"><br><p></p><p><img src="@@PLUGINFILE@@/parahippocampal%20gyrus.png" alt="parahippocampal gyrus" width="1077" height="1239" class="img-responsive atto_image_button_text-bottom"><br></p><h4>Tiff Thompson's Depth Theory of Neuroanatomy</h4><p></p><p>Proponents of
the collective unconscious theory in neuroscience have suggested that neurobiological
correlates to the collective unconscious are the subcortical areas of the
brain, specifically the thalamus (which oscillates in delta, theta, and alpha
rhythms). The thalamus operates like a regulatory gateway, since all of the
sensory input that comes into the brain, and all motor output, goes through the
thalamus. The thalamus regulates what goes in and what goes out.&nbsp; Because these structures are located centrally,
linking the brain with the rest of the nervous system, they are said to control
vital processes, such as emotions and long-term memory (Hunt, 2012). Arousal
occurs in the face of a threat, triggered by the amygdala, which is an almond
shaped structure in the brain responsible for mediating the fear response. The
amygdala locks down the hippocampus so as to react by shutting down this
structure, the seat of the memory (LeDoux, 1998b). LeDoux speculates, however,
that psychoanalysis works by strengthening the cortical control of the
amygdala. In fact, the face-to face reciprocity between infant and mother is
crucial for the development of the pre-frontal cortex, which serves to mediate
the amygdala and regulate affect (Schore, 1994, 2003; Siegel, 1999; Stern,
2013; Tronick, 2007).</p>

<p>Sigmund Freud, quite rightly, believed
that mental activity
was rooted in phylogenically­ old emotion &nbsp;and motivation
&nbsp;systems, which
were constructed&nbsp; in early mental development, and instantiated throughout later adult life (LeDoux, 1998a;Panskepp, 1998). Thus, affective reactivity, such as dissociation, can be seen as a return
&nbsp;to nonverbal, largely unconscious parts of the brain. These are areas that can influence the higher-ordered new-mammalian brain
(Cozolino, 2002, p. 6). Furthermore, these older regions are innervated
&nbsp;by the vagus nerve,
which literally means "wandering nerve." The vagus nerve is also called the "wandering nerve" because it's the longest
nerve in the human body and has countless branches
that wind their
way from the brainstem all the way down to the lowest
part of the intestines, touching
most major organs along the way. The vagus nerve is the tenth
&nbsp;cranial nerve and is the main afferent pathway connecting the gut to the brain. This nerve modulates the parasympathetic nervous system, which counterbalances the fight, flight,&nbsp;<span style="font-size: 1rem;">or freeze stress response
by eliciting the so­
called "relaxation &nbsp;response."</span></p><h4><span style="font-size: 1rem;">The Vagus Nerve</span></h4>

<p>&nbsp;<img src="@@PLUGINFILE@@/Vagus%20Nerve.jpg" alt="Vagus Nerve" width="500" height="1859" class="atto_image_button_text-bottom">A study released in June of 2015 noted the
discovery of vessels directly connecting the brain
and the lymphatic system, a finding which will likely
have continual substantial implications for major neurological diseases and also more common &nbsp;psychopathologies (Louveau
et al., 2015). This finding changes
the way scientists
perceive neuro-immune interaction, and may make the link between the body and the brain/mind something beyond esotericism.</p><br><p></p><p></p></div><p></p>