Brain Renaissance: From Vesalius to Modern Neuroscience by Catani Marco Sandrone Stefano

Author:Catani, Marco, Sandrone, Stefano
Language: eng
Format: epub
Publisher: Oxford University Press
Published: 2015-08-29T16:00:00+00:00

FIG 22.3 Left: A frog loses the ability to coordinate movement after damage to the left cerebellum (Onimus, 1872). Right: This soldier suffered a severe injury to his right cerebellum. Ten weeks later his right thigh can be fully flexed onto the chest, his heel placed on his buttock, and his foot flexed upwards with minimal effort (Holmes, 1917).

Early attempts to divide the cerebellum included an old “paleocerebellum” in the anterior regions and an evolutionary “younger” posterior “neocerebellum”. Key to this division were stimulation studies based on novel methods, such as the targeted positioning of stereotactic probes or axonal tracing, which helped decode the pattern of connections between the cerebellum and the rest of the brain. By 1888, parcellation of the cerebellum was also dividing scientific opinion, nowhere more so than in London. When neurologist John Hughlings Jackson speculated that these new patterns of connection suggested that the cerebellum had an opposite representation of the body compared with the cortical one, where the head is represented on the upper part and the feet on the lower regions, his colleague William Gowers scoffed at the localizationist idea. Instead, in the first edition of his Manual of diseases of the nervous system, it was Flourens’s original unitary concept that Gowers favored. Moreover, taking a forerunning stance, he was convinced that the cerebellum contributes to higher cognitive functions:

“[The cerebellar hemispheres] are connected chiefly with those parts of the cortex of the cerebrum which chiefly subserve psychical processes. . . . Hence it seems possible that the old theory may be correct which assumes that the cerebellar hemispheres are in some way connected with psychical processes.” (Gowers, 1888)

The debate between these two giants of neurology reached an impasse. But by the time Gowers and Jackson had begun their squabble, many had already turned their attention to a new and different way of viewing biological phenomena, including the brain.

The advent of powerful microscopes was providing anatomists with a wealth of new insights into the makeup of tissue, no more so than when Theodor Schwann stepped forward with his theory that the basic unit of life was the humble cell (see chapter 35). It was hoped that by exploring the microscopic features of the cerebellum it might be possible to determine whether it really was specialized. Thus the search for neurons that were unique to the cerebellum begun. In 1838, Jan Purkinje indentified previously undescribed “flasked-shaped ganglion bodies” in cerebellar tissue. These large, elaborately branched neuronal cells would go on to take his name (Purkinje cells). Then, in 1874, Camillo Golgi announced a second population of cerebellar cells, which he identified using his newly discovered black staining method. These too would end up bearing his name (Golgi’s cells) (Golgi, 1874).

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