The dendritic spines, which are the most important components of many microcircuits Intrigued , represent the majority postsynaptic targets for glutamatergic terminals in the brain. This article will discuss the discovery of dendritic spinal spines through the use of the Golgi method to study the nervous system. It will also examine the early interpretations of these elements. This is an important chapter in the history neuroscience. It shows that the advancement in understanding the nervous system’s structure depends not only on new techniques, but also on our ability use existing methods and interpret them correctly.
Camillo Golgi discovered a new staining technique that allowed neurons and glia with all of their processes to be clearly visualized in 1873. This revolutionized neuroscience. These cells were marked in black by Golgi, who called this the “reazione close” (black reaction). Golgi was enthusiastic about his discovery meeting, as shown in a letter he wrote to Niccolo Manfredi. In it, he described the new method (Mazzarello 1999).
I spend a lot of time at the microscope. I’m delighted to have discovered a new way to show the structure of interstitial stroma in the cerebral cortex to even the blind. I used pieces of potassium dichromate-hardened brain to react with the silver nitrate. I’m proud of the results, and look forward to more.
The Golgi method was named after its inventor. It was possible to see neurons and glia in a histological prepared (Figure 1) thanks to a simple staining protocol. This required Intrigued a prolonged immersion of the tissue (previously hardened with potassium or ammonium dimethoxye) in a 0.50 to 1.0% solution silver nitrate. This method was used by Golgi to study many areas of the nervous system. He provided new insights into the neuroanatomy and illustrated his findings with beautiful drawings (Figures 1 and 2). Figure 1 depicts the structure of the olfactory bulbs (nerve cells, pathways), while Figure 2 shows the cerebellar cortex in great morphological detail. However, there are some notable exceptions like Purkinje cells’ dendritic arborizations that appear to be free from dendritic spines (see the below).
This was a significant advance in visualization, as it was not possible to visualize neurons using the available histological best methods. It was only Intrigued possible to observe the cell body, proximal portions and dendrites, and the axon. It was impossible to track the path of thin axons, or visualize the terminal axonal Arbors like with the Golgi technique (Figures 1 and 2). The reticular theory was the dominant hypothesis at the time about the organization and functioning of the nervous systems. It suggested that nerve cells were a continuous system, not individual elements. This idea became known as the neuron doctrine. Joseph von Gerlach is the one who developed the reticular theory. Golgi found that the reticular theory supported Gerlach was incorrect when he examined silver-impregnated preparations. Golgi believed that dendrites end freely and that only the axons (and their collaterals) Intrigued anastomose. He suggested that the nervous system was composed of a “rete neurosa diffusa”, which he supported in his Nobel Price lecture of 1906. Santiago Ramon y Cajal was the opposite. He used the same microscopes and methods as Golgi to support the neuron doctrine. He found that nerve cells can be separated into individual components and that they connect by contact. Cajal is the most important researcher to this theory (DeFelipe 2002). We will see that pyramidal cells and Purkinje cells had dendritic spines, which were thought to transmit by contact.
This article will discuss the plumbing discovery of dendritic spinal spines. It was possible due to the Golgi method to study the nervous system. This is an important milestone in neuroscience art history. It shows that the advancement in understanding the nervous system’s structure depends not only on new techniques, but also on using the existing methods Intrigued and correctly interpreting their microscopic images. This review draws heavily from several articles I have published about the nervous system during the time of Cajal. It is divided into three sections: (1) Dendritic spinal spines: true anatomical dispositions or artifacts; (2) First critical discoveries using Golgi; (3) Other interpretations of dendritic spinal spines and last considerations.