High Quality Content by WIKIPEDIA articles! Ablative brain surgery (also known as brain lesioning) is the surgical ablation by various methods of brain tissue to treat neurological or psychological disorders. The lesions it causes are irreversible. There are some target nuclei for ablative surgery and deep brain stimulation. Those nuclei are the motor thalamus, the globus pallidus, and the subthalamic nucleus. Ablative brain surgery was first introduced by Pierre Flourens (1774–1867), a French physiologist. He removed different parts of the nervous system from animals and observed what effects were caused by the removal of certain parts. For example, if an animal could not move its arm after a certain part was removed, it was assumed that the region would control arm movements. The method of removal of part of the brain was termed "experimental ablation". With the use of experimental ablation, Flourens claimed to find the area of the brain that controlled heart rate and breathing. Ablative brain surgery is also often used as a research tool in neurobiology. For example, by ablating specific brain regions and observing differences in animals subjected to behavioral tests, the functions of the removed areas may be inferred. Experimental ablation is used in research on animals. Such research is considered unethical on humans due to the irreversible effects and damages caused by the lesion and by the ablation of brain tissues. However, these effects of brain lesions (caused by accidents or diseases) on behavior can be observed to draw conclusions on the functions of different parts of the brain.