What Happened To You?: Conversations on Trauma, Resilience, and Healing

The brain stem is the lowest part of the brain that is connected to the spinal cord. With respect to biological function, it is responsible for the regulation of automatic vital functions such as respiration and maintenance of heart rate. Essentially, the brain stem and its functioning are rooted in survival. It is the first to develop, and information enters the brain stem first before ascending to higher and more complex parts of the brain. It is the lowest layer described in Perry’s representation of the brain as an upside-down triangle. Its survival function causes associations created there to be implicit and strong; meant to be adaptive in nature, these associations can become maladaptive if formed owing to trauma and persist beyond the confines of a negative experience, as in the case of PTSD-associated flashbacks.

The cortex, or more specifically the cerebral cortex, is the brain’s outermost layer of nerve cell tissue. This is the part of the brain responsible for uniquely human traits such as the capacity for cognition. It is the seat of all higher-order cognitive processes including attention, perception, awareness, memory, language, attitudes, beliefs, consciousness, intelligence, and personality. It is the last part of the brain to develop completely, and it is said to attain maturity only in an individual’s mid-twenties. Just as the brain develops sequentially from bottom to top, so too does it process information, and the cortex is the last layer to receive information, particularly in a condition of threat or danger. This is owing to human biology, which causes the survival instinct to kick in and the cortex to shut down when faced with danger, causing a suspension of logic and reaction from instinct. The cortex is most accessible when one is relaxed, secure, and feels safe. It is also the most malleable part of the brain, with great potential for learning.

The diencephalon constitutes the second layer in Perry’s representation of the human brain. It refers to the caudal (lowest) part of the forebrain, located in the center of the human brain, and in anatomical terms, it is seen as either continuous with the brainstem or included as part of it. The diencephalon works as a relay and processing center for sensory information, as well as connects structures of the endocrine system with the nervous system, making it responsible for arousal, sleep, appetite, and movement.

Dissociation is one of the stress-responses described in the book, different from the stages of arousal that are a function of the fight-or-flight responses. In contrast to the latter, dissociation presents in situations when either fight or flight are not viable options to cope with the immediate threat; thus, the mind “dissociates” or escapes from the situation at hand, and the individual finds themselves retreating into an inner world. This is characterized by a disconnection between one’s internal and external world, specifically a lack of continuity between thoughts, memories, actions, and surroundings. In a non-threatening situation, daydreaming is an example of dissociation; however, dissociation can feel like an out-of-body experience when a person is experiencing a traumatic event, such as in the case of rape or sexual abuse. Prolonged instances of dissociation, often in response to frequent or continuous presentation of traumatic circumstances, such as childhood sexual abuse, can lead one to develop a dissociative disorder.

Epigenetics refers to the study of how one’s behavior and environment can influence changes in one’s genetic functioning. Epigenetics concerns itself with reversible changes rather than irreversible ones, the latter of which are rooted in one’s inbuilt DNA sequence. The basic premise of epigenetics is that one’s genes behave like switches, which can be turned “on” or “off” by the environment and one’s experiences. Lifestyle factors such as diet and exercise can result in epigenetic changes, such as contributing to or reversing lifestyle diseases like high blood pressure or diabetes. However, the basic genetic sequence remains the same—epigenetic changes do not delete or create new genes, they merely affect genetic expression, i.e., which genes are turned “on” or “off,” and how. This relatively recent field of study highlights the connections between one’s genes, environment, and behaviors.

The limbic system is located underneath the cerebral cortex and above the brainstem. It is the part of the brain responsible for human emotions and directing related behavioral responses, especially with respect to behaviors needed for survival, such as feeding, reproduction, and stress-response. Thus, the limbic system is responsible for the regulation of hunger, thirst, and mood, as well as the neurochemical reward system that aids learning and habit formation. Relatedly, it is the seat of emotion and autobiographical memory.

Neuroplasticity refers to the brain’s capacity to change through growth and reorganization. This is a function of the neural networks in the brain that can be wired and rewired to function in different ways based on exposure and experiences. Neuroplasticity is a feature of the human brain in childhood as well as in adulthood—even the adult brain can change with enough training. However, the developing brain is seen to have a higher degree of plasticity than the adult brain, meaning that experiences in the earlier years of one’s life have a disproportionate effect in shaping and organizing the brain’s development.

Regulation, specifically emotional self-regulation, refers to an individual’s ability to exert control over one’s emotional state and respond to experience in a manner that is adaptive and socially acceptable. It is a skill learned over years of experience and simultaneous brain development, rather than an inborn trait. Babies are unable to regulate themselves, and they require caregivers to participate in co-regulation, or interactions between the caregiver and the child that see the former soothing the latter, which helps the infant regulate distress. With predictable, consistent, and reliable responses on the part of the caregiver over time, the infant gradually develops the ability to regulate and learns effective strategies for the same.

Resilience refers to the successful adaption to difficult life experiences, and is characterized by mental, emotional, and behavioral flexibility to accommodate changing internal and external demands. Resilience is not inbuilt; it is developed over time with regulated exposure to moderate, predictable, and controllable doses of challenge, with the scaffolding of loving and nurturing relationships. Adequate caregiving in the early years of an individual’s life allows them to develop healthy stress-response systems, ensuring resilience in the face of future hardship.

Sensitization refers to the phenomenon by which repeated exposure to a stimulus eventually causes an amplified reaction to the same stimulus. In the context of trauma, it plays out as frequent, prolonged, inconsistent, and intense exposure to stress in the early years of life, leading to the sensitization of the individual’s stress-response systems. Rather than build resilience, this experience lowers one’s threshold for stress, and leaves one overly reactive to typically mild or moderate levels of stress.