The isolated mention of the existence of a powerful Jewish polity in the Horn of Africa by Jewish traveller Benjamin of Tudela in the twelfth century AD has generally been given such credence by the twentieth-century orientalistes that it is often considered the first mention of the people later to be known as Falasha. This short passage has indeed engendered a large amount of scholarly literature, which has partially obscured the wider historical and geographical context to which it refers and (...) in which it was produced. Beyond his formulation of the hypothesis of this Jewish polity, which, it will be argued, probably never existed, this article suggests that Benjamin's Jewish viewpoint has much more to tell us about the regional scene than has been recognized. First, analyzed as an itinerary, Benjamin's text sheds new light on the trading routes of the time. Second, the comparison of this text with other sources from the twelfth and thirteenth centuries provides new perspectives on the religious, political, and economic intricacies of the time, a context in which, it is suggested, Benjamin's confusion about the identity of the polity he describes makes sense. Finally, while it probably does not constitute a reflection on a political entity that existed in actual fact, Benjamin's narrative, with all its ambiguities, may be considered a rather faithful mirror of the social complexity of the communities near the Red Sea and the Horn of Africa, which are at the crossroads of several worlds. (shrink)

Deciding between different voluntary movements implies a continuous control of the competition between potential actions. Many theories postulate a leading role of prefrontal cortices in this executive function, but strong evidence exists that a motor region like the primary motor cortex is also involved, possibly via inhibitory mechanisms. This was already shown during the pre-movement decision period, but not after movement onset. For this pilot experiment we designed a new task compatible with the dynamics of post-onset control to study the (...) silent period duration, a pause in electromyographic activity after single-pulse transcranial magnetic stimulation that reflects inhibitory mechanisms. A careful analysis of the SP during the ongoing movement indicates a gradual increase in inhibitory mechanisms with the level of competition, consistent with an increase in mutual inhibition between alternative movement options. However, we also observed a decreased SP duration for high-competition trials associated with change-of-mind inflections in their trajectories. Our results suggest a new post-onset adaptive process that consists in a transient reduction of GABAergic inhibition within M1 for highly conflicting situations. We propose that this reduced inhibition softens the competition between concurrent motor options, thereby favoring response vacillation, an adaptive strategy that proved successful at improving behavioral performance. (shrink)