Some aspects of the history of the law of dynamic polarization of the neuron. From William James to Sherrington, from Cajal and van Gehuchten to Golgi

William James was the first to suggest that propagation of impulses in the nervous system proceeds in one direction, from sensory to motor neurons, but not viceversa. His law of forward direction preceded the formulation of the law of dynamic polarization of van Gehuchten and Cajal, which assumed that nerve impulses are conducted cellulipetally along dendrites and cellulifugally along axons, based on different anatomo-functional properties of these neuronal components. Golgi did not accept the law of dynamic polarization because he believed that dendrites are involved in the nutrition of the neuron rather than in impulse propagation, and that impulses can travel in any direction in the axonal components of the diffuse nerve network. Sherrington in turn experimentally demonstrated that intraneuronic conduction is reversible, whereas, in accord with James's law, propagation of impulses along neuronal chains is irreversible, due to the valve-like action of synapses. The story of the law of dynamic polarization shows that neither Golgi nor Cajal paid much heed to Sherrington's findings and to neurophysiological studies in general, probably because they felt that histology alone could provide the key for understanding the general functioning of the nervous system. It is argued here that this attitude was detrimental to the progress of the neurosciences, because a multidisciplinary approach based on different techniques is inevitably called for in order to develop a plausible theory of the nervous system.     

Alcohol and the family in Canada

In the context of the family in Western society, alcohol often has been viewed as a problem. This article traces how the use of beverage alcohol in Canada related to the family in the transition from the preindustrial to late-twentieth-century era. Powerful temperance movements in the nineteenth century, and divisive prohibition policies in the early twentieth, attempted to protect the material and moral health of the family. Although liquor laws and social attitudes became more open starting in the 1930s, the medicalized discourse on alcoholism in the 1940s and 1950s was linked to notions of the family. Liberalization of retail and on - premise sales of alcohol in the 1960s and 1970s attempted to portray moderate drinking by adults as "normal" family activity. In the last quarter of the century, a neotemperance movement, reacting to issue such as impaired and driving and teenage drinking, suggested that alcohol's relationship to the family remained highly ambiguous.     

The origin of the term plasticity in the neurosciences: Ernesto Lugaro and chemical synaptic transmission

The Italian psychiatrist Ernesto Lugaro can be regarded as responsible for introducing the term plasticity into the neurosciences as early as 1906. By this term he meant that throughout life the anatomo-functional relations between neurons can change in an adaptive fashion to enable psychic maturation, learning, and even functional recovery after brain damage. Lugaro's concept of plasticity was strongly inspired by a neural hypothesis of learning and memory put forward in 1893 by his teacher Eugenio Tanzi. Tanzi postulated that practice and experience promote neuronal growth and shorten the minute spatial gaps between functionally associated neurons, thus facilitating their interactions. In addition to discovering the cerebellar cells known by his name and advancing profound speculations about the functions of the glia, Lugaro lucidly foresaw the chemical nature of synaptic transmission in the central nervous system, and was the first to propose the usage of the terms "nervous conduction" and "nervous transmission" in their currently accepted meaning.     

Descartes' embodied psychology: Descartes' or Damasio's error?

Damasio (1994) claims that Descartes imagined thinking as an activity separate from the body, and that the effort to understand the mind in general biological terms was retarded as a consequence of Descartes' dualism. These claims do not hold; they are "Damasio's error". Descartes never considered what we today call thinking or cognition without taking the body into account. His new dualism required an embodied understanding of cognition. The article gives an historical overview of the development of Descartes' radically new psychology from his account of algebraic reasoning in the early Regulae (1628) to his "neurobiology of rationality" in the late Passions of the soul (1649). The author argues that Descartes' dualism opens the way for mechanistic and mathematical explanations of all kinds of physiological and psychological phenomena, including the kind of phenomena Damasio discusses in Descartes' error. The models of understanding Damasio puts forward can be seen as advanced version of models which Descartes introduced in the 1640s. A far better title for his book would have been Descartes' vision.