How did the discipline of cognitive neuroscience emerge and develop? In the following, the most important historical landmarks will be briefly described that led into the development of this exciting scientific discipline. It is important to note that while research on the interrelationships between the brain and mind have not been called cognitive neuroscience until relatively recently, the first attempts to map correspondence between the brain and the mind took place already hundreds of years ago. Sometimes even the early attempts of the Greek philosopher Aristotle to connect mind and the heart are mentioned as initial steps towards localization of mental functions, even though it was Plato, the mentor of Aristotle, who believed the brain to be the seat of mental processes.
In the 17th Century Europe there were theoretical formulations advanced by Rene Descartes of nerves containing animal fluids, the movement of which were thought to carry sensory and motor information, however, the realization that neurons (i.e., specialized cells that make up the nervous system) are important for cognition (the "neuron doctrine") emerged thanks to staining methods developed by Italian scientist Camillo Golgi. These methods allowed one to visualize neurons in tissue samples (Golgi, 1873, Pannese, 1996), for an example of this, see Figure 1-1 below. These staining methods were utilized by Ramón y Cajal in his subsequent work (Ramón y Cajal, 1899, 1904, Andres-Barquin, 2001). Together, Golgi and Ramón y Cajal received the Nobel Prize for their work in 1909. In the neuron doctrine, which still is valid today, it is assumed that a single neuron is the elementary building block of cognition (neurons are described in detail in Chapter
4). Despite of these significant advances, it was not until the 19th Century that research specifically addressing brain-mind interrelationships begun emerging.
Phrenology: an early attempt to localize mental functions
The first attempt to specifically connect specific brain regions with mental functions was introduced by German scientists
Franz Joseph Gall and Johann Gaspar Spurzheim, who started the discipline of phrenology in the turn of the 18th and
19th Centuries (Gall and Spurzheim, 1809, Simpson, 2005). Phrenology was based on mapping the interrelationships between depressions and bumps in the skull with various personality features (see Figure 1-2). The idea behind this was that more developed brain areas, which would go with more developed aspects of personality, would create small bumps in the skull. Thus, it was surmised that by studying the correlations between personality features (such as "hopefulness" and "firmness") and the bumps in the skull one would be able to construct a brain map of personality. While phrenology has been today most often mentioned as a good example of pseudoscience, it is one of the first documented instances where there was an attempt to localize aspects of mental processes to the brain.