(Johannes Muller, 2014). The doctrine of specific nervous energies was his most important contribution to the study of behavioral physiology. He observed that all nerves carry the same basic message, but that we discern that the message from different nerves is not the same. Due to his doctrine of the specific nerve, experiments were carried out directly on the brains of animals, which was carried out by Pierre Flourens, a French physiologist. This was called experimental ablation. He then claimed to have discovered the part of the brain responsible for breathing, heart rate control, purposeful movements and auditory reflexes. Shortly after, this experimental ablation was applied to a human brain. This observation made it possible to show that a part of the cerebral cortex located at the front of the left side of the brain fulfills the functions necessary for speech. This remains important for understanding the brain. (Behavioral physiology,