PART 1: THE STRUCTURE AND FUNCTION OF THE BRAIN
INTRODUCTION TO THE BRAIN
Trauma, according to the fifth edition of the “Diagnostic and Statistical Manual of Mental Disorders” (American Psychiatric Association, 2012, p. 271) results from “exposure to actual or threatened death, serious injury, or sexual violence in one (or more) of the following ways: directly experiencing the traumatic event(s); witnessing, in person, the traumatic event(s) as it (they) occurred to others; learning that the traumatic event(s) occurred to a close family member or close friend (in case of actual or threatened death of a family member or friend, the event(s) must have been violent or accidental); or experiencing repeated or extreme exposure to adverse details of the traumatic event(s).”
The first step toward fully understanding the devastating effects of trauma should be a neurological one-that is, understanding the structure and function of the brain the sufferer is forced to use to both experience and then process it. As an organism, it is the center of his universe and the most complicated structure in existence.
“The human brain is the most complex structure in the universe,” according to Professor Ken Ashwell in “The Brain Book” (Firefly Books, 2012, p. 9). “Nothing-not even the most advanced computer-comes close to equaling its performance in carrying out feats of information processing. And no computer has anything like a sense of self. Yet each one has a multifaceted sense of ourselves as a unique individual.”
Interpreting and processing information both about the world within the body and the world without, it can be considered the command enter of the nervous system, enabling its user to make decisions and induce, usually and automatically, his glands and muscles to effectuate the changes that ensure physical health and stability, all by means of converting stimuli into electrical signals.
BRAIN GROWTH AND DEVELOPMENT
Progressing from an embryo to infancy, childhood, adolescence, adulthood, and advanced age, the human being begins as a single cell created by the fertilized egg, which carries the genetic code form his parent or sperm donor.
After 18 days of gestation, the brain assumes initial form as a racket-shaped neural plate that appears on the embryo’s surface and already contains the map of its ultimate parts. From the front portion the forebrain will develop and from its tail will grow the spinal cord. During ensuing gestation, the sides of the neural place fold upward, forming a tube over a three-day interval.
Ridges from the plate’s thickening walls give rise to neural crest cells, which themselves produce the cells of the peripheral nervous system (PNS).
Actual brain shape solidifies between 28 and 50 days. Three bulges at its end develop into the fore-, mid- and hind-brain sections.
After birth, a baby’s brain, at about three-fourths of a pound, is only a quarter of its eventual weight, with increases to two pounds after the first year of life and 2.2 pounds after two years of life. Early experience sparks the growth of the brain’s nerve cells or neurons.
The rate of brain size growth significantly decreases between the ages of two and eight, resulting in overall weight gains of only about 20 percent. Despite that deceptive number, the amount of additional brain tissue now incorporates a significant increase in connections, which enable the baby to acquire the necessary cognitive and motor skills he will use as he matures.
Childhood experiences are instrumental in his development.
“Experiences during childhood-good and bad-can have long-lasting effects on behavior later in life,” according to Ashwell (ibid, p. 103). “Many studies have shown that children who have been abused or neglected during childhood are at a much higher risk of developing anxiety and depression during adult life. Stress early in life causes a rise in the stress hormone cortisol in the blood and a reduction in the number of receptors for cortisol in the brain. These changes are believed to predispose the person to anxiety and depression when stress and misfortune occur during adult life.”
Although most of the brain-controlling processes cease by adolescence, two important developments continue: (1). Important executive function areas of the cerebral cortex continue to mature, albeit at a slow rate, and (2). Poised on the threshold of adult life with its responsibilities and demands, the person acquires complex cognitive capabilities and motor skills.
The period between approximately 25 and advanced age can be considered the middle years, during which up to 30 percent of the brain’s volume can be reduced because of its pruning of no longer needed nerve cell connections. Although this results in subtle behavioral and cognitive changes, and these reconifigurations accelerate in the very late years, intellectual and motor skills acquired early in life have become mostly automatic; therefore, a person can remain both functional and alert. This mental and physical activity, retaining original and sometimes even prompting new nerve cell connections, can delay further decline.
At significantly advanced ages, a reduction in the number of neurons, synapses, and neurotransmitter levels, even in the absence of any neurodegenerative diseases, can further reduce brain weight, decreasing mental flexibility and psychomotor speeds, the difficulty in learning new skills, and reducing processing and response capabilities.
Since all brains do not age at the same rate, and physical and mental activity, along with genetics, can have positive influences on it, decline can considerably vary, but long-term memory and personality remain.
THE SKULL
Because of the brain’s gelatinous composition and delicate tissue, it is protected by bones that collectively form the skull.
“The braincase is made up of a skull base, including the occipital, sphenoid, petrous temporal and frontal bones,” according to Ashwell (ibid, p. 64), “which form three bowl-shaped depressions into which the lower parts of the brain fit snugly.”
THE CEREBRAL HEMISPHERES
When viewed from above, it is evident that the brain is subdivided into two (left and right) cerebral hemispheres, each of which governs the motor control and sensations of the body side opposing it. Left hemisphere functions include, among others, motor control of the body’s right side, movement of both eyes to the right, touch and pain sensations on the body’s right side, and goal-oriented planning. Right hemisphere functions include motor control of the body’s left side, touch and pain sensations on the body’s left side, movement of both eyes to the left, appreciation of the emotional aspects of music and speech, and rationalization of emotionally difficult decisions.
Two regions concerned with language, Broca’s Area and Wernicke’s Area (named after neurologists), are only located in the left hemisphere, although studies have shown that those belonging to 15 percent of left dominant handed people are located in the right hemisphere.
Spatial perception is mostly located in the right hemisphere of all.
The corpus callosum, a bundle of between 250 and 300 million axons, facilitates connections and communication between the two hemispheres.
A VERTICAL PROFILE OF THE BRAIN
If the brain were viewed from the side, it would consist of the upper portion, the cerebral cortex; the midbrain, which is in the upper portion of the brainstem and facilitates emotions; and the brainstem itself, which descends from the thalamus to the spinal cord.
THE CEREBRAL CORTEX
Subdivided into the four lobes of frontal, parietal, temporal, and occipital, the cerebral cortex caps the forebrain, which is its largest part. Under the lobes themselves and deep within the core is the insula. One third, or appxoximate9y 30 billion, of all nerve cells facilitate neural processing and high levels of executive functioning, with further functional subdivisions for aspects such as motor control, touch, sound, smell, taste, sight, spatial perception, balance, and planning.
THE BRAIN CORE
Within the brain core is a group of structures and cells, linked together to foster smooth movement, which facilitate sensory, endocrine, cognitive, and movement functions. They include the following.
1). Basal Ganglia: The collection of nerve cells itself, the basal ganglia fosters emotion, decision making, and movement control.
2). Thalamus: Consisting of two large, egg-shaped structures, located on either side of the third ventricle and itself the biggest of the structures that constitute the diencephalon, receives and interprets incoming stimuli and information, processes it, and routes or relays it either above, to the cerebral cortex, or below, to the brainstem.
3). Hypothalamus: Located just below the thalamus, the relatively small hypothalamus governs the nervous system’s automatic functions, the endocrine system’s glands, the heart rate, and the blood pressure, all of which play roles in emotional responses. It also provides conscious satisfaction of animal needs, including eating, mating, and the body’s internal environment.
THE BRAINSTEM
The brainstem, located between the thalamus and the spinal cord connection, is subdivided into the three components of midbrain, pons, and medulla oblongata, and in turn provides three major functions.
1). It serves as the central nervous system’s nerve pathway, whose travel is bidirectional-that is, both up and down.
2). As the processing center of sensory information, it controls bodily function by means of mostly subconscious commands to organs.
3). “(It) allows us to process sensory information from the cranial nerves and to control the muscles and glands of the head and neck to consume and digest food and communicate by speech and facial expression,” advises Ashwell (ibid, p. 40).
It is from the brainstem, which has changed little throughout the centuries and is almost identical to that in lower food chain animals, that the brain ultimately evolved into higher-functioning areas, particularly the cerebral cortex. Its nerve pathways connect it, via the intermediate brainstem, with the spinal cord.
BRAIN CELLS
Sensations, thoughts, and actions are controlled by the brain and the spinal cord through the nerve cells.
“Nerve cells, also called neurons, are concerned with processing information and transferring (it) to other nerve cells in that complex network that makes up the brain,” notes Ashwell (ibid, p. 72).
Nerve cells themselves consist of an axon, which transfers information to other neurons; tree branch-resembling dendrites, which stretch up to 0.2 inches in length to receive the information; and axon-surrounding myelin sheaths, which augment faster, more reliable electrical impulses. Neurotransmitters are chemical messenger molecules, which bridge the synaptic cleft between them, sparking changes in the recceing cell’s electrical behavior and creating a neuropathway. Transfer speeds depend upon axon diameter and the existence or absence of myelin sheath coating.
The actual electrical signal transfer is designated an “action potential” and is considered an all-or-nothing-at-all sequence-that is, either the bridge between the neurons will be completed or it will not be initiated. There is no turning back midway across the cleft.
Multiple nerve cell connections are considered circuits. Their repeated use as neuropathways creates progressively thicker connections and it takes concerted effort to change a person’s thoughts so that he can forge new ones.
SYSTEMS
Several systems, activated by and responding to brain impulses, spark physiological, emotional and behavioral changes, ensuring internal homeostasis and regulation and augmenting the person’s survival potential.
The nervous system, the first of them, is subdivided into the central nervous system (CNS), which consists of the brain and the spinal cord, and the peripheral nervous system (PNS) that sends impulses to both. The latter can be further subdivided into the somatic nervous system, which controls voluntary functions, and cautoromic nervous system, which controls the automatic ones.
The limbic system, located on the border (or “limbus” in Latin) of the forebrain, is a dual system, consisting of the amygdala, a group of almond-shaped nerve cells-“amygdala” is Latin for “almond”-in the temporal lobe and the hippocampus, cortical tissue also in the temporal lobe, and connected by means of the amygdala outflow and the papez circuits, thus forming a link between memory and emotion.
Vital to understanding the mechanism and routing of trauma is the amygdala itself.
“The most important tasks performed by the amygdala is to link sensory stimuli and emotional experience,” according to Ashwell (ibid, p. 244). “This allows them to learn whether experiences are positive or negative and is profoundly important in regulating future behavior. The amygdala also lets us recognize anger and fear in the faces of others. Stimulation of the amygdala in humans produces a feeling of anxiety and the experience of déjà vu (the feeling of having experienced the same situation before).”
Strongly influencing a person’s nervous system, defenses, and emotional responses through his internal organs, it generates a fight-or-flight dynamic, so severely dictating his actions that he may have little to no control over them.
“The pathway to the cerebral cortex… allows the amygdala to influence decisions about movement that serve the satisfaction of basic drives, and to serve links between the perception of objects, (such as) a snake, and appropriate emotional responses, (such as) fear… ,” Ashwell continues (ibid, p. 34.) “The pathway to the hypothalamus allows the amygdala to initiate the physical changes in emotional responses.”
The final system is the autonomic one, so designated because it is considered automatic or not under the conscious control of the person. Subdivided into the sympathetic and parasympathetic nervous systems, they maintain the body’s internal environment and use energy reserves during emergency times.
Preparing a person for survival-intended actions, the first of the two increases the heart rate, opens the airways, and redirects blood from the stomach to the muscles.
The second both complements and counteracts the first by restoring regulation, thus lowering the heart rate and decreasing blood pressure.
Full, simultaneous activation of both divisions seldom occurs.
The enteric system, also an autonomic system division, controls the movement of digested substances, food, and liquid through the gastrointestinal tract.
CHEMICALS AND HORMONES
Several chemicals and hormones are instrumental in behavior and emotion.
Adrenalin, both a hormone and a neurotransmitter, is released into the bloodstream during stressful, emergency, and life-threatening times, whether they are real or only perceived, to create fight-or-flight responses intended to improve and increase a person’s safety and survival-that is, it increases the heart rate, blood pressure, airflow to the lungs, and blood flow to the muscles. During panic attacks, it acts like an overheating engine, overriding the autonomic system and rendering it impossible for the person to regulate himself.
Cortisol, a stress hormone secreted by the adrenal cortex, controls mood, motivation, and fear, and aids in the body’s fight-or-flight responses.
Dopamine is a neurotransmitter chemical used by the neurons of the midbrain’s substantia nigra to regulate motor activity, pathway-routed to the limbic system and medial cortex to augment motivation and cognition. Although it rewards behavior by amplifying the brain’s pleasure centers, misuse of its pathway can lead to addition.
Melatonin is a hormone produced by the pineal gland to control circadian rhythms, a 24-hour cycle in the physiological processes of living beings.
Finally, serotonin is a neurotransmitter used by brainstem cells to control sleep-awake cycles, moods, and pain perceptions by means of upper and lower pathways.
PART 2: TRAUMA
Familiarization with brain structure and function can immeasurably aid the neurological understanding of trauma, which alerts a person to perceived or possible danger by gearing the body for survival-promoting strategies.
There are levels of trauma severity, however. Major ones include life-threatening accidents, rapes, losses, abuse, parental or primary caregiver alcoholism, para-alcoholism, and/or abandonment, and horrific events, such as wars, terrorism, the 9/11 attacks, and the holocaust. Lesser traumas include living with someone who himself suffers from post-traumatic stress disorder (PTSD); overexposure to media reports about terrorism; growing up with economic insecurity; harassment, sexual or otherwise, in school or in the workplace; extended periods of illness or pain; and behaving in ways that are opposed to the person’s core beliefs.
Integral to all of these adverse experiences is fear.
“Fear is the acute emotion that is usually experienced when confronted with a dangerous or painful situation, whereas anxiety is the anticipation of painful and unpleasant experiences and may be felt over a much longer period of time,” advises Ashwell (ibid, p. 246).
Incoming stimuli, which can number in the hundreds of thousands on any given day, enter the brain through the thalamus, its router, which then relays it through two possible paths-the slow upper one or the faster lower one.
In the case of the slow upper route, information entering and routed by the thalamus is sent to the cerebral cortex for processing and understanding, and the hippocampus.
In the case of the fast lower route, the information is sent directly to the amygdala. This pathway, sparking the characteristic overtaking and controlling sensations because the amygdala is inextricably tied to the hypothalamus, results in several fundamental differences.
1). It is faster, overriding the logic and reasoning of the upper route through the cerebral cortex, whose path it cuts off.
2). It floods the blood with adrenalin stress hormones, which increase the heart and blood pressure rates.
3). It activates the sympathetic division of the autonomic nervous system, which increases airflow to the lungs and redirects blood to the muscles, initiating the survival-promoting, fight-or-flight response.
4). It drives the person’s response behavior, controlling him with floods of stress hormones to either combat or flee from the danger, real or perceived.
5). It is reactive in nature.
6). It creates, via the sympathetic division, a rupture in the autonomic system, which the parasympathetic division cannot counteract or reregulate, leaving the energy locked in. Because it cannot be discharged, later retriggerings create post-traumatic stress disorder.
Like emotionally going off line, the person who suffers from PTSD can have any or all of the following symptoms: bracing, exaggerated startle effects, eruptive rage as opposed to anger, hypervigilance, numbing, dissociation, cognitive distortions and misinterpretations, the inability to sustain intervals of calm without assistance, and the same emotional and physiological effects that were generated by the original trauma, leaving him to believe that it is just as real now as it was then.
Understanding these neurological, physiological, and emotional concepts can greatly aid an adult child, who experienced abusive, dysfunctional, and alcoholic upbringings, in his life’s plight.
Most likely subjected to an original trauma at an early age that could be measured in months, unable to resolve or even understand it, hypervigilant for repeated danger as he is held captive to sometimes raging, out-of-control parents or primary caregivers, developing PTSD, and adding layer upon layer to his dilemma, he is forced to filter much of his life through the amygdala, leaving little surprise as to why he was (or still is) afraid of people, places, and things.
“Eventually, even imaging the situation may cause a rise in blood pressure and heart rate that we experience as anxiety,” according to Ashwell (ibid, p. 247).
Regressing to the age of his original trauma, despite being an adult who may have already passed the half-century mark in life, he re-experiences now the same tool-devoid, powerlessness he felt then, thus explaining one of the adult child survival traits, “We are reactors, not actors.”
“Trauma,” according to Roger Keizerstein, a clinical social worker and therapist in East Setauket, New York, “is an injury to the autonomic system, not (just) an event. Post-traumatic stress is the way in which the body speaks the unspeakable. (And) healing begins in a place between stimulus and response.”
Article Sources
Ashwell, Ken. “The Brain Book.” Buffalo, New York: Firefly Books, 2012.
“Diagnostic and Statistical Manual of Mental Disorders,” Fifth Edition. American Psychiatric Association, 2013.
“PTSD and Biofeedback: From Emotional Deregulation to Homeostasis and Resilience” Course, taught by Roger Keizerstein at Stony Brook University, Stony Brook, New York, September 17, 2019.