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  • Writer's pictureKathleen Choe

Cross Brain Connections: What Are They Good For, Anyway?

There is a great deal of discussion in Trauma Informed Care about cross brain connections, neural pathways that connect throughout the different areas of the brain, leading to a greater capacity for self-regulation and smooth emotional state shifting in response to environmental cues. Brain development begins in utero, developing sequentially from the bottom to the top and from the inside out in response to sensory input. The first part of the brain to develop is the brainstem, which is responsible for regulating autonomic functions like heart rate, breathing, blood pressure, body temperature, sleep and appetite. We generally do not have think about these functions unless something goes wrong with them. The brainstem, which as it name suggests, is at the base of the brain, is responsible for basic survival, and is where our fight, flight and freeze responses originate in response to a traumatic situation.

The next region of the brain to develop is the diencephalon which regulates motor control. (When the freeze response is triggered by the brainstem it indicates that the diencephalon, as well as all of the regions of the brain above it, has gone off line). Following that is the limbic system, which regulates our emotions and makes us capable of attachment and relational connection. The last part of the brain to develop is the neocortex, which allows for abstract and concrete thought, impulse control, planning and other aspects of executive functioning.

Trauma can be defined as input that is arrhythmic and unpredictable. If a pregnancy is unwanted, or the mother is in a chaotic environment due to poverty, domestic violence, struggles with a mental disorder or uses drugs, for example, the fetus is exposed to a barrage of arrhythmic sensory input in the womb. The mother’s heart-rate may be irregular, the cadence of her voice may be harsh or distressed, and her body may be secreting stress chemicals like cortisol and adrenaline that acid wash the womb for nine months. The part of the brain that receives the most sensory input will be the most developed, as the neurons flock there in response to continuous activation. A baby experiencing intra-uterine trauma of any sort will be born prepared for survival, with most of his or her neurons clustered in the lower regions of the brain. A baby whose gestation was full of rhythmic, predicable sensory input from his mother’s well-regulated heartbeat, calm voice, and soothing chemicals like dopamine, serotonin and oxytocin, will be born with up to fifty per cent of his neurons having migrated to the neocortex, ready for language and learning. Intra-uterine trauma primes the baby’s brain to form local connections in the lower regions of the brain in anticipation of being born into a chaotic, unpredictable environment. The foundation for future development is compromised, and any subsequent trauma layers on top of this shaky substrate to create a brain muscled up for survival and reactivity, with few cross brain connections allowing for a regulated, integrated response to environmental or relational stimuli.

Dr. Bruce Perry points out that trauma interferes with what he terms smooth “state shifting,” referring to ability of the brain to communicate between all of its regions to come up with the best response to deal with the situation at hand. Healthy brain development allows a person to accurately interpret input and respond appropriately based on what is actually happening in the present. In the case of a car careening into your lane of traffic, the amygdala sounds the alarm in the limbic system, the diencephalon kicks in and prompts you to quickly maneuver out of the way, and the brainstem briefly shuts down unnecessary functions like digestion that would divert energy away from dealing with the crisis. The neocortex, which would unnecessarily delay the response time, goes off line. Whether the car barreling towards you is a Mercedes or a Chevrolet is completely irrelevant to your survival. Determining the color, make or model of the vehicle occupies precious time and attention that keeps you in harm’s way longer than necessary and compromises your ability to keep yourself safe. When cross brain connections are absent, and the different regions of the brain lack neural pathways to communicate efficiently, the array of responses a person has is limited. A traumatized individual might get stuck in his brainstem, lose access to his diencephalon, freeze, and be unable to turn the steering wheel, incurring a collision with the oncoming car.

Cross brain connections are essential for flexible thinking and appropriate responses. Practicing mindfulness and grounding skills on a regular basis allows these neural pathways to develop and strengthen in a brain compromised by arrhythmic, unpredictable input. Research continues to highlight the neuroplasticity of the brain in response to rhythmic sensory input that allows it to heal and integrate following trauma. Expanding local connections into cross brain connections enhances our ability to experience emotional regulation so that we can build healthier, more satisfying relationships with ourselves and with others.

How does one build or repair cross brain connections? A daily practice of mindfulness (meditation or centering prayer, for example) has been shown to improve brain connection and functioning. Exposure to reparative or corrective relational experiences also contributes to building neural pathways from the lower to the upper regions of the brain. Trauma victims often repeat dysfunctional patterns in relationship due to compromised neural connections in the brain, reinforcing their trauma pathways. Equine Assisted Psychotherapy involves partnering with a horse to provide opportunities for new pathways to form as a healthy relationship is built between horse and human under the guidance of a therapist and equine specialist. Clients learn how to build and sustain healthier relationship patterns as their brains literally re-wire through the experiential component of the therapeutic work with the horses. Through a combination of ground and mounted work, a person can learn self-regulation skills, positive coping resources, and begin to heal from their trauma. For more information, check out the following websites: and

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