History of Neuroscience – Free Online Neuroscience Course

Hello friends!

This is Lesson 2 of our Free Online Neuroscience Course! Today, we’re going to talk about the history of neuroscience. In other words, what is the history of the study of the nervous system, central and peripheral?

When we study history, at school or college, we know that whenever we are going to study a subject, we have to go back in time a little earlier (perhaps a few centuries), in order to be able to understand the conditions and causes of events that directly affected the subject we are studying. . Thus, if we are going to study the neurosciences and their rapid development in the 20th century, we will have to go back in time and study research and studies that were their conditions of possibility.

Egypt, more than Greece, is the cradle of Western civilization. Thousands of years ago, the Egyptians performed brain surgery. However, what exactly was done, how and for what purpose was lost in time. We know that such surgeries were done because we find perforations in the skull in skeletons from that time. Papyri from the 15th century BC. C also describe intracranial procedures. What is known today is that they were able to relate motor functions to the brain.

Unfortunately, the real story of what happened and the level of knowledge of the Egyptian doctors is practically lost.

With that, we have to go forward in time and start the history of neuroscience a few centuries later, in Greece. Hippocrates, the father of Western medicine, defined the brain as the seat of the mind. He wrote: “It should be known that he is the source of our pleasure, joy, laughter and amusement, as well as our grief, pain, anxiety and tears, and none other than the brain. It is specifically the organ that enables us to think, see and hear, to distinguish between ugly and beautiful, bad and good, pleasure and displeasure. It is the brain that is also the seat of madness and delirium, of the fears and frights that take us over, often at night, but sometimes also during the day; it is where lies the cause of sleeplessness and sleepwalking, of thoughts that will not occur, forgotten duties and eccentricities.”

Reading this quotation – with the knowledge we have today – it is incredible to observe the acuity of Hippocratic thought. The great research problem for the neurosciences has always been how to study the brain and the entire nervous system in a living organism. When dissecting a cadaver, it is possible to see the brain, meninges, spinal cord, and nerves radiating from the spinal cord to the limbs. But how to relate these structures with functioning, with physiology when the body is alive?

In view of this, between the conceptions of Hippocrates and the 20th century, we find more conjectures (close to philosophy and theology) than real, empirical, laboratory knowledge for the knowledge of the nervous system.

However, before we reach the last century, we must mention important discoveries and hypotheses that, although they have been shown to be wrong, have helped researchers to advance knowledge.

The 19th century and phrenology

Perhaps you have already seen films that show the great popularity of Gall’s phrenology in the 19th century. The idea of ​​this German doctor was that, from the cranial projections, it was possible to establish personality types, or rather types of mind. The name phrenology comes from the Greek: φρήν, phrēn, “mind”; and λόγος, logos, “logic or study”.

The problem mentioned above (of observing the functioning of the living brain) should be solved with the possibility of measuring the skull. We can understand this conception by thinking about the following. The brain, within the skull, has several regions. Each region is responsible for a function of the mind. So if a subject develops more than one of these functions, that part of the brain grows, putting pressure on the part of the skull that is nearby, creating bumps and bulges that can be measured.

Gall’s argument, in the opinion of current neuroscientists, was correct only in considering that the brain has regions or locations that are responsible for certain functions. However, the 35 locations described by Gall are not correct. In fact, they are imaginary locations for imaginary functions, that is, invented by him. And therefore the measurement of the skull for the assessment of personality or for the assessment of the development of certain functions is meaningless.

Florens and the aggregate field

Still in the 19th century, Jean Pierre Florens, a French physician, defended a thesis contrary to Gall’s. Studying pigeons and rabbits with brain trauma, he noticed experimentally that the functions of these animals were not impaired by the injuries. Such research led him to argue that the brain did not work through specialized regions (argument of localizationists), but worked as an aggregated field.

The aggregate field theory, therefore, was based on the experimental study of animal physiology, and in that sense it was a breakthrough. Continuing his study, Florens proceeded to remove the cerebellum from rabbits and pigeons and concluded that muscle functions were only momentarily impaired. Cognitive functions were affected only with the removal of the cerebral hemispheres, too, temporarily. The final conclusion was that the brain worked as a whole, that is, the cortex, cerebellum and brainstem worked as an aggregated field. In other words, injuries were healed over time by activating other nearby areas.

In this way, he initiated the movement against the localizationists, establishing the globalists’ argument.

Florens defined the aggregate field as follows: all sensations, perceptions and desires occupy the same space in the brain.

Jackson and the Topographic Organization of the Brain

JH Jackson, instead of studying animals, started studying the human brain, in epileptic patients.

See also – Epilepsy: types, symptoms and role of the psychologist

Observing in detail the seizures of epileptics, Jackson noticed that they all had similar motor movements. From this information, he concluded that epileptics must have a brain problem in a specific part of the brain. The explanatory model is that of the mental map, each brain region controlling a motor part, in other words, this is the topographical conception of the brain. Remembering that tops, in Greek, it means place. In this way, Jackson – with other data – returned to defend the localizationist position, taking a big step beyond Gall’s imaginary ideas.

Paul Broca and Carl Wernick – Language and the brain

During psychology college, I studied Broca’s discoveries, which were one of the most important in the history of neuroscience. Here, of course, we are bringing a panoramic view of this story. In other lessons, we will pick up specific points and go deeper.

The two researchers, Broca and Wernick, were able to carry out the first major research into the specific location of a function in the brain. They accomplished this feat by studying damage to parts of the brain and its effect on psychic functions. It all started in 1861 when Broca evaluated a man who could understand language but was unable to speak. The only word he could speak was “tan”. Later, they discovered that this man had a lesion in the left frontal lobe, which was called – from then on – Broca’s area.

Wernicke, a German neurologist, studied a patient who could speak but often uttered nonsense sentences. This patient had suffered a stroke and, although he could speak, he could not understand spoken or written language. The stroke lesion had been in the posterior part of the left temporal lobe, a place that became known as Wernicke’s area.

Both Broca’s and Wernicke’s findings supported – with evidence – the localizationists’ point of view, that is, lesions in specific areas of the brain caused specific behavioral changes, that is, they discovered two exact regions in the brain for the expression of speech and speech. speech understanding.

Later, in the 20th century, with the development of neuroimaging, a set of techniques for medical diagnosis such as tomography, scintigraphy and magnetic resonance, knowledge of the nervous system grew a lot and thousands of other studies were carried out. We will talk more about these researches in the next texts.

Before we conclude, I would also like to mention the research of the German physician Alois Alzheimer, who also contributed to the expansion of our knowledge about the brain.

See here – What is Alzheimer’s?

Diagnosis and Treatment of Alzheimer’s

In our next Lesson of the Online and Free Neuroscience Course it will be about the Central and Peripheral Nervous System, already with the great discoveries of the 20th century and, mainly, the 1990s, the decade of the brain.

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