Before Robert Whytt, little was known about human reflexes. Whytt was able to advance our knowledge through a series of experiments; he published the results in 1751. Previous scientists had noticed that decapitated animals (and people) still had muscle twitches. Whytt used decapitated animals to systematically show that he could make their muscles twitch by poking or pinching a leg. Clearly, basic reflexes did not require the brain. Whytt went beyond that though. He was able to dissociate reflex action from the brain by severing nerves between the spinal cord and an appendage. When the connection to the spinal cord was lost, there was no reflex. Whytt’s discoveries about reflexes went beyond simple automatic reflexes. He recognized that there was voluntary and involuntary action. The reflexes that he discovered the spinal cord played a large role in controlling were involuntary. He distinguished between voluntary and involuntary actions and stated that voluntary actions, if practiced enough, become habits. Habits, he stated, became more and more automatic with further practice. So while automatic and voluntary reflexes and actions are distinct they are not mutually exclusive. Whytt’s research was the forerunner to 20th century behaviorism, specifically classical conditioning.
A number of years after Whytt published his work, two independent researchers Sir Charles Bell and Francois Magendie discovered the functions of the two main nerve tracts in and out of the spinal cord. While Bell receives a lot of credit, Magendie’s work was the more scientific and documented – Bell just had a lot of political sway. What did these two researchers discover? Magendie exposed the spinal cord of a live dog and severed the posterior verve tract. The dog could still move its limbs but had no sensation in the affected area. Magendie was then able to sever the anterior root of a nerve tract. He discovered that the animal still had sensation in the affected area but no movement. He put the findings together and stated that the efferent anterior nerves controlled movement while the afferent posterior nerves controlled sensation. Bell had earlier discovered essentially the same thing. The law about the functioning of the nerve pathways became known as the Bell-Magendie law. Neurologists and neuropsychologists have been able to use this law as the basis for understanding different types of central nervous system injury.
The man had committed a crime and was sentenced to pay. A crowd gathered to watch his punishment. There standing before him was the fateful Madame, the progeny of a French engineer. This Woman with the acerbic jaw was to seal the criminal’s fate. He faced the crowd wide-eyed and fearful, pleading for his life. His pleas seemed to fall on deaf ears as the frenzied crowd prepared for the spectacle. A German man stood waiting to play his part. Theodor Bischoff was not there to enjoy the public execution, he was there in the name of science. As the executioner led the criminal to the apparatus named after Joseph Guillotin (who by the way did not invent the guillotine), Bischoff approached. The blade fell and the criminal’s head dropped to the ground. Bischoff quickly rushed over to the head to perform his experiment.
This was not true but back in the day it seemed a very logical explanation, especially in light of the new discovery about how the heart worked like a pump for blood. The pineal gland was Descartes ideal structure where mind and body interacted because it was in the middle of the brain and was a singular brain structure (most structures in the brain are in both hemispheres. So for example, there are two hippocampi, two caudates, two frontal lobes, etc…). Even with Descartes advances, psychology remained a philosophy until the 1800s when Wundt and other empiricists created experimental psychological laboratories. From there, the field of psychology grew exponentially into the major field it is today.