A historical review of investigations on laterality of emotions in the human brain

Different models of emotional lateralization, advanced since the first clinical observations raised this issue, will be reviewed following their historical progression. The clinical investigations that have suggested a general dominance of the right hemisphere for all kinds of emotions and the experimental studies that have proposed a different hemispheric specialization for positive vs. negative emotions (valence hypothesis) or for approach vs. withdrawal tendencies (motivational hypothesis) will be reviewed first and extensively. This historical review will be followed by a short discussion of recent anatomo-clinical and activation studies that have investigated (a) emotional and behavioral disorders of patients with asymmetrical forms of fronto-temporal degeneration and (b) laterality effects in specific brain structures (amygdala, ventro-medial prefrontal cortex, and anterior insula) playing a critical role in different components of emotions. Overall, these studies support the hypothesis of a right hemisphere dominance for all components of the emotional system.     

Amerigo Vespucci and His Alleged Awareness of America as a Separate Land Mass

ABSTRACT

The Florentine Amerigo Vespucci is widely believed to have been the first European to realize on his third voyage (May 1501 to September 1502) that America was a separate land mass, unconnected to Asia and completely surrounded by water, a communis opinio refuted in the present article. Close analysis of the geographical terms used in Vespucci’s letters, and their comparison with early sixteenth-century printed cosmographies, suggest that, on the contrary, Vespucci regarded the newly discovered land mass as a southern extension of the Asian continent. Also discussed are Matthias Ringmann’s 1507 Cosmographiae Introductio and Martin Waldseemüller’s 1507 world map, whose depiction of America as a separate land mass, allegedly based on Vespucci, paved the way for a concept that could not have been recognized as geographical truth in early sixteenth-century Europe.