Which part of the brain does not play a role in higher order functions?

The reptilian brain, often referred to as the "reptilian complex," primarily encompasses the most primitive parts of the brain that are responsible for basic survival functions. These include instinctual behaviors such as aggression, dominance, territoriality, and basic functions like heart rate and breathing. It does not engage in the higher-order functions often associated with more advanced areas of the brain, such as complex problem-solving, emotional regulation, and adaptive reasoning.

In contrast, the neocortex is crucial for higher-order functions like sensory perception, cognition, and complex decision-making. The limbic system plays a significant role in emotions and memory, which are also vital in higher cognitive functions. The orbitofrontal cortex is involved in decision-making and social behavior, contributing to the capacity for nuanced thinking and emotional intelligence. Therefore, the distinction lies in the reptilian brain's focus on more instinctual, survival-based functions rather than the complex and abstract operations characteristic of higher-order thinking.