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A major goal in systems neuroscience is to characterize normal cortical dynamics. Numerous in vitro and in vivo studies demonstrated that ongoing cortical dynamics are characterized by cascades of activity across many spatial scales, termed neuronal avalanches. Avalanche dynamics are identified by¬ two measures (1) a power law in the size distribution of activity cascades, with an exponent of -3/2 and (2) a branching parameter of 1, which reflects a balance in the propagation of cortical activity at the border of premature termination and potential exponential blow up. Here we analyzed resting state brain activity recorded using MEG from more than 100 healthy human subjects. We identified discrete events in the MEG signal and segmented them into cascades, using multiple timescales. Cascade-size distributions were found to obey power laws. At the timescale where the branching parameter was close to the critical value of 1, the power law exponent was -3/2, in line with expectations for neuronal avalanches. This behavior was robust to scaling of the number of sensors and to coarse-graining the sensor resolution. As controls, phase-shuffled data with the same power spectrum or empty-scanner data did not exhibit neuronal avalanches. These results indicate that normal resting cortical dynamics are well described by a critical branching process. Both theory and experiments suggest that cortical networks with such critical, scale-free dynamics optimize various types of information processing. Neuronal avalanches could thus provide a biomarker for disorders in information processing, paving the way for novel quantification of normal and pathological cortical states.

During the Middle Ages (roughly 600-1500 CE), the physicians of the Islamic world were renowned for their efficient prevention and treatment of illnesses. Authors like Avicenna (Ibn Sina) and Rhazes (al-Razi) composed medical encyclopedias that were used in Latin translations in European medical schools down to the 18th century, and in their Arabic original, are still used in India in the present day. Moses Maimonides (the Rambam) rose to become head of the Jewish community of Egypt not only because of his halachic knowledge, but also due to his prestige as one of Saladin’s physicians.
This lecture will present a brief outline of major aspects of medical theory and practice in the pre-modern Islamic world. I will discuss the emergence of an Islamic medicine from its Greek, Persian and Arabian antecedents; developments in therapy, especially in pharmacy and surgery; medical training and medical ethics; the place of Jewish physicians and pharmacists within the medical marketplace; and alternatives to learned medicine.