 In our previous blog, we discussed the brain and its various characters. As a refresher, the brain is comprised of two keys players: the limbic system and the pre-frontal cortex. The limbic system is the “animal” part of our brain; it is where our emotions originate and houses our fight-or-flight response system. The limbic system sits deep down in the center of our brain and is surrounded by the outer cortical surface of the brain called the cortex. The cortex is comprised of five major lobes: the frontal, parietal, temporal, occipital, and cerebellar areas. Each of these lobes play a distinct role in human function, but the frontal lobe, arguably, may be the most important in terms of human consciousness.
The frontal lobe is segmented into a handful of definitive areas, one of which is called the prefrontal cortex (PFC). Sitting at the most anterior portion of the frontal lobe in our forehead region, the PFC is responsible for a myriad of functions. At the top of the list, the PFC is mainly in charge of executive function (Siddiqui, 2008). Executive function includes many of the everyday tasks we need to function in society, such as an ability to pay attention, retain new information, communicate with others, and engage in goal-directed behaviors. The PFC functions at peak performance when we are listening to a teacher explain a new concept, brainstorming new ideas with our boss at work, or planning a family vacation. The PFC has also been linked to each individual’s overall intelligence level, as many IQ tests challenge the PFC’s responsibilities directly. As mentioned in the first edition of this blog, the PFC interacts with the limbic system on a constant basis. The PFC acts as the gatekeeper to our emotionally charged limbic system and ensures our emotional impulses are kept in check and our needs are being met. However, this delicate communication system can be severely compromised when the PFC becomes injured. An injury to the PFC can come about in hundreds of different ways. Perhaps of the most famous brain injuries every recorded occurred in the fall of 1848 (Garcia-Molina, 2010). Phineas Gage was born in New Hampshire and found work as a railroad constructor, taking him all the way to the western coasts of California. At the age of 25, a tragic accident occurred. Phineas Gage was standing over an area of rail line that exploded, causing an iron tamping rod to rocket out of the ground straight upwards into the left side of Phineas’ skull. The rod penetrated through his left jaw, traveled behind his left eye socket, and exited out of the top of his left frontal lobe. Shockingly, he survived, and lived 12 more years before dying of an epileptic seizure. However, those 12 years were marked by extreme personality changes for Phineas, and this dramatic injury changed the medical community’s understanding of the significance of the PFC in a person’s neuropsychological function. While the story of Phineas Gage is severe, many injuries to the frontal lobe often result from everyday occurrences. In the United States, motor vehicle accidents and slip-and-fall accidents account for over half of all traumatic brain injury (TBI) hospitalizations (Center for Disease Control and Prevention, 2021). In addition, concussions and TBI’s from sport-related accidents are also becoming increasingly concerning. Both children/adolescent and professional sports such as football, hockey, lacrosse, and soccer are gaining national media attention for athletes suffering from long-term head injury symptoms. So, what happens exactly when the frontal lobe is injured? The PFC sits in the foremost portion of the frontal lobe, directly behind the bones of our forehead. There is little space between the PFC and these skull bones. The PFC is suspended in the skull and its’ only protection from the skull bones are thin layers of tissue and membrane. During a head impact event, the delicate tissue of the PFC can be jostled back and forth, causing it to come into contact with the skull bones. Next, the brain ricochets backwards, and this forward and backward momentum continues until the brain reaches a resting point. Imagine a piece of Jello sitting on a plate: as the plate moves back and forth, the Jello jiggles front to back and side to side. Even once the plate becomes still, there may still be subtle movements of the Jello due to physics and the properties of inertia. While the brain is not quite Jello consistency, it is this movement that often results in the traditional symptoms we associate with concussions and TBIs. The U.S. Department of Veteran’s Affairs and Department of Defense defines and classifies severity of TBI using the following criteria: loss of consciousness, memory loss, altered mental state, neurological deficits, Glasgow Coma Scale, and imaging results. Common symptoms of mild TBI include:
In addition, depending upon the severity of injury, other parts of the brain’s cortex can become injured, resulting in additional symptoms that are often difficult to diagnose at face value. Injury to the PFC can greatly alter a person’s ability to function in everyday society. For many, a TBI diagnosis can have lifelong impacts and depending upon a person’s specific recovery, may or may not improve over time. However, there are many therapeutic options for TBI treatment. Perhaps one of the most helpful interventions can simply be understanding what a brain injury is and how the PFC changes after an injury. Through the use of psychoeducation, we can begin to better understand how our PFC functions post-injury and in turn, make appropriate accommodations at work, school, and home. As we learn to better understand how the PFC functions and what it needs for recovery, we can learn to give ourselves grace and the time it often takes to adapt to a new way of functioning. Living with a brain injury is challenging, but with the right resources and support from loved ones and health care providers, thriving with a brain injury is possible. The office of Hilary Morris, LPC provides psychological services and trauma therapy for those struggling with emotional symptoms following TBI or concussion. They provide psychotherapy to help clients learn to gain control over episodes of anxiety or panic. Their clients integrate changes into their daily life and make peace with their brain injury recovery process. For more information on brain injury and brain injury recovery, please refer to these organizations advocating for TBI-patient care:
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 Meet the Characters
The brain is a complex organ. It controls everything humans think and feel and allows us to interact in an ever increasingly multifaceted world. But, when you get right down to it, the brain looks quite fragile and uncomplicated. So how can such a humble-looking organ cause so much distress in our everyday lives? I think this question is best answered by one of my favorite science blog writers, Tim Urban. He explained there are two forces in our brains working together (and sometimes against each other) that control every thought, every emotion, every aspect of our functioning. According to Tim, these two characters exist to keep us safe and in control of our environment, and also allow us to feel the pleasures of a fresh-baked cookie or a warm summer breeze. These characters also allow us to feel loss, grief, and emotional pain that can often shift the entire course of our lives. While our brains are not completely segmented into two characters, per se, the brain develops over time and two key biological systems work together to form human consciousness. The first character to discuss is the limbic system of the brain. Evolutionarily speaking, this is an old brain system that all mammals possess. It is the part of our brain that responds immediately to danger and sits quietly in the background when we are relaxing at home. There are few things the limbic system has to worry about – mainly our immediate safety and what we are feeling in any given moment. The human limbic system is similar to that of an animal brain: when a threat appears, the limbic system jumps into action through a rush of adrenaline, intricate muscle movements, and an increase in heart rate and blood pressure. These reactions to danger keep the animal alive for another day, and the human limbic system has helped our species survive and thrive for millennia. The next character in our brain’s development story is that of the prefrontal cortex (PFC). The PFC came along in human evolution approximately 6 million years ago and gave rise to language, emotional expression, and high-level executive functioning (Smaers, et al, 2017). The PFC helps us to rationalize situations, create imaginative scenarios in our minds, and respond appropriately to threats. Unlike the limbic system who is easily startled at every noise, the PFC can take in information from our senses to better understand the noise and whether or not our survival is at risk. Working together, the limbic system and the PFC have shaped the human brain into the machine it is today. These two characters play vital roles in our everyday functioning and also inform our life’s biggest decisions. These characters allow us to feel the thrill of a roller coaster without truly fearing for our lives. They allow us to love another person so deeply while also making logical decisions about marriage and commitments. They allow us to feel and to think simultaneously. But what happens when these characters are no longer playing on the same team? What happens when one character has more power than the other? The Limbic System vs. The PFC The interplay between the limbic system and the PFC in the brain is quite refined and delicate. When these systems start to work against each other, the destruction to human function can feel like a never-ending battle. When the PFC is in charge, things may seem reasonable on the surface. A person may appear to be logical, rational, smart, and never makes a wrong decision. With the wave of a wand, things seem to fall into place. However, bubbling below the surface, you may find a suppressed limbic system waiting to angrily take over. We often stereotype people who are run by their PFC as being cold, calculated, or having a difficult time expressing emotions. With the PFC running the show, life is done and is often successful, but may not be enjoyed to its fullest potential. On the other hand, the limbic system can just as easily run the show. When this system is in charge, a person may feel every emotion so deeply that the ups and downs of everyday life are joyous and catastrophic at the same time. A person being driven by the limbic system may even start to appear as animal-like: skittish, easily startled, shy, and wary of their environment. However, the limbic system also allows us to develop meaningful relationships, love unconditionally, and protect ourselves from danger. Pitting the limbic system and the PFC against each other can certainly be a recipe for disaster. And even though we may think the PFC is smarter, he often loses this battle…but why? The PFC often loses because he is young in terms of the evolution of the human brain. The limbic system, on the other hand, has been around for tens of millions of years (Smaers, et al, 2017). The limbic system is the human brain’s default network and when threatened, jumps in to take control. The Limbic System Runs the Show It is no wonder why humans, when exposed to an acute stressor, react before we think. This is our limbic system taking over the PFC to keep us out of harm’s way. The fight or flight network came pre-installed in humans and the PFC is like a new software upgrade. As hard as we may try, this default networking in the human brain is unchangeable. At birth, the limbic system is just about fully developed. A few weeks into life, the limbic system is in full work mode. Infants cry for everything they need; eating and sleeping are about as complex as life gets. Its not until much later into puberty that the PFC comes online. The PFC reaches full maturity around late teens to early twenties and even then, can spend a few more years developing. By the time the PFC makes his appearance and begins to fully contribute to human functioning, the limbic system has been around for more than a decade. As an example, when a stressful life event occurs when we are children, the limbic system is all we have to rely on. We may have left our trusted blanket or stuffed animal at the playground and we cry and scream that it is gone forever. The limbic system thinks that this dependable, deeply loved, and necessary item is key to our survival and we will panic until it is returned to our grasp. As the PFC is not yet in the picture, we as children have no way to understand that we are responsible for the lost blanket, and logically must retrace our steps to go retrieve it. However, even as fully developed adults with properly developed PFC’s, the limbic system can still take over and run the show. There are many ways this can happen, and in the following series, we will talk about the ways the limbic system can take charge over our functioning, leaving the PFC far behind. |
AuthorsMichaela Olson is a registered psychotherapist with over 6 years of experience working with traumatic brain injury and recovery. Archives
February 2022
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