At last we come to the neomammalian complex (or cerebral neocortex). This third part of the brain is represented in the hand model by the fingers and top surface of the hand. This part of the brain is unique to primates. There is also an even more highly evolved brain that is unique to humans. The neocortex is responsible for things that make us distinctly human: logic; reasoning skills; higher-order thinking skills such as analysis and problem-solving; speech and verbal understanding; meaning-making; willpower; and, wisdom.
The goal of successful trauma processing is to move, or to connect, the emotionally charged material out of the limbic brain, into the neocortex, the part of the brain that is more efficient in its long-term storage capacities. Metaphorically speaking, trauma processing allows the lines of communication between the two brains to become more open so that these shifts in storage can occur. However, until that occurs, the neocortex is of little help for trauma resolution and healing. To illustrate this concept, try to recall a time when you attempted to reason with someone in crisis. It probably didn't go very well. Or, have you ever tried to think logically and rationally when your body is crying out from the exhaustion of chronic stress? Because unhealed trauma hasn't reached the cerebral cortex, it means it may be unresponsive to cognitive-rational approaches to healing.
Cognitive therapy (also called cognitive behavioral therapy) often encourages people to leave the past in the past, and instead focus on the present or the here-and-now. While these sorts of interventions are helpful for some things, they are not particularly helpful for trauma integration. Cognitive therapies or any reason-based interventions primarily target the prefrontal regions of the brain (logic, reason, and time awareness). However, it was the limbic region of the brain that was activated during the original trauma to help the person survive (through flight, fight, or freeze). During traumatic experiences, when the limbic brain is activated, the prefrontal lobes go offline. This makes perfect sense from a survival perspective. You can't reason your way out of tiger attack. For a person in crisis or intense emotional distress, whether in real time or in response to triggers from earlier, unprocessed experiences, no amount of reasoning will help.
So why would any of us attempt to appeal to a part of the brain that isn't really "on?" For optimal healing to occur, all three brains must be able to work together. Neurologically, unprocessed trauma creates disconnection in the brain. If this sounds alarming complex, don't panic. You will not need a team of experts to devise ways for the three brains to work together. Pause here and take a nice deep breath. Great! All three brains worked together during that slow deep breath. Deep breathing might be considered a whole brain intervention. Breath originates in that primitive reptilian region of the brain. Likewise, any movement-based or body-based intervention automatically works within the limbic and reptilian brains.