Two contradictory viewpoints in the same research field won the Nobel Prize in Physiology at the same time

The Nobel Prize ceremony in 1906 was a lively and exciting event.

Santiago Ramón y Cajal, known as the father of "modern neurology," won the Nobel Prize in Physiology together with Camilo Golky.

Although they won the Nobel Prize for their achievements in the same research field, their views on neurophysiology were very different.

Network Theory

The first person to propose the network theory of nerves was a German histologist named Joseph Gerlach. He believed that the human nervous system is a network-like structure.

Every neuron cell clearly visible under the microscope is connected into a whole in some way, just like the vascular network in the human body.

In this way, the nervous system can form a complete structural and functional unit and realize complex operational functions. Gorky was a supporter of Joseph Gerlach's reticular theory.

Joseph Gerlach, Image source: Wikipedia

The reticular theory was supported by a large number of academic researchers in the biological academic community at that time. Its strong theoretical support lies in the fact that once it is assumed that the nervous system is a naturally connected whole and that there is some kind of invisible connection between cells, there is no need to continue to consider how each scattered cell cooperates with each other, and many discussions on detailed issues can be omitted.

Camillo Gorky, Image source: Wikipedia

Neuron theory

Another school of neuron theory, represented by Cajal, believes that nerve cells exist independently, that neurons are a physiological unit of the human central nervous system, and that each neuron is an independent entity.

Dendrites and axons extend from the nerve cell body, which is responsible for support and nutrition.

Cajal Image source: Wikipedia

How was the neuron discovered by Cajal?

In 1873, Italian scientist Maximilian Golgi invented the silver dichromate staining method, mixing silver nitrate with potassium dichromate to prepare silver dichromate, and used silver dichromate to stain brain tissue.

Golgi found that the staining effect of most brain tissues was not ideal. Only about 3% of neurons appeared very clearly under the action of silver dichromate, but the complete structure of a neuron could be clearly observed.

Five years later, Cajal, who had just returned from medical school, improved the silver staining procedure, and the technique of silver staining was further developed.

Cajal observed the finer structures of nerve cells and took the opportunity to display his talent for painting - he drew detailed nerve cells and recorded his observations faithfully. Later, these paintings of Cajal became classics.

Cajal's drawing of pyramidal neurons in the cerebral cortex on paper in 1904. Image credit: Cajal Institute (CSIC), Madrid

Under a microscope, Cajal discovered a key point: there was a gap between the axons of nerve cells and other cells, and they were not tightly connected. Since then, he has adhered to the principle of seeing is believing and became a firm supporter of the neuron theory.

He summarized the research of his predecessors and put forward three important inferences about the neuron theory:

First, the signal of a nerve impulse is transmitted from one neuron to the next by excitation.

Second, the cell body, axon and dendrites of nerve cells can all generate action potentials.

Third, neurons produce a "dynamic polarization" phenomenon, and the signal transmission of nerve impulses is orderly, with dendrites transmitting to the cell body, and the cell body transmitting to the axon.

These three inferences accurately describe the core process of signal transmission in the nervous system.

However, since various experimental methods and equipment were not well developed at that time and people's cognitive level was limited, the two influential factions in the academic community each held their own opinions, and neither faction had sufficient evidence to completely overturn the views of the other.

Electron microscopy advances neuron theory

It was not possible to visually observe the connections between nerve cells until 50 years after Cajal's time.

After the invention of the electron microscope, the neuron theory received the strongest support, and biologists finally determined the status of the neuron theory in the academic world through a series of new studies.

However, even though it was impossible to reconcile Cajal and Golgi's differences on the neuron theory, the 1906 Nobel Prize in Biology was still awarded to these two scientists with completely different conclusions.

Because both of them have made great contributions to human research on life, enabling humans to understand themselves more advanced. Scientific research always pursues objectivity, but the research value of Cajal and Golgi's research on the morphological structure of the nervous system is beyond doubt in the academic community.

The wheel of history rolls forward. With the advancement and development of science and technology, the research theories of predecessors have laid the foundation for the important position of neuron theory as the cornerstone of today's neuroscience theory. Cajal naturally became the founder of neuron theory.

Observation and evidence are the most important test criteria in natural science research.

As Cajal said in his 1906 Nobel Prize acceptance speech: "It is true that the method of analysis would be very economical and convenient if we assumed that the motor and sensory nerves of the nervous system were connected in an unbroken network, but unfortunately, nature does not seem to care for the human ingenuity's taste for convenience and consistency, and prefers complexity and variety."

END

Review expert: Zhu Guangsi, member of Beijing Science Writers Association.

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