AP PSYCHOLOGY

Detailed explanation-1: -Answer and Explanation: The region of the brain that appears to have the oldest evolutionary history is the brainstem.

Detailed explanation-2: -The oldest is the “reptilian brain, ” designated “R-complex, ” which consists of the ventral striatum and the basal ganglia. The R-complex is the definition given by MacLean to structures that evolved from the floor of the forebrain during development.

Detailed explanation-3: -The brainstem is critically important for the survival of an animal. It lies between higher centres and the spinal cord and constitutes one of the oldest parts of our brains.

Detailed explanation-4: -The reptilian brain, the oldest of the three, controls the body’s vital functions such as heart rate, breathing, body temperature and balance. Our reptilian brain includes the main structures found in a reptile’s brain: the brainstem and the cerebellum.

Detailed explanation-5: -Evolutionarily, the brainstem is the most ancient part of the brain. Structurally, it can be divided into the medulla oblongata, pons, and midbrain.