From invertebrate olfaction to human cognition: emerging computational functions of synchronized oscillatory activity.

摘要

Oscillations and synchronization are fundamental processes in many biological systems, from prokaryotes to humans on time-scales that range from milliseconds to days (Winfree, 2001; Gillette and Sejnowski, 2005). In nervous systems, synchronized oscillations are prevalent in active assemblies of neurons. They have been recorded in a wide variety of species, from invertebrates to humans. Although the function of some of these oscillations appears obvious, such as those related to breathing and locomotion, the functions of others, such as those related to human cognition, remain elusive. The human cortex generates oscillations in many frequency ranges, as evidenced by electroencephalography (EEG). Much progress has been made since the original description of the human EEG (Berger, 1929), and we are beginning to understand the mechanisms underlying network oscillations in the mammalian cortex. Recent experiments have shifted focus from studying pacemaker mechanisms to studying the interaction of multiple local oscillators and have revealed an important role of GABAergic interneurons in such local network oscillations. These and other recent developments have been extensively reviewed previously (Steriade et al., 1993; Steriade, 2000; Buzsaki, 2002; Whittington and Traub, 2004; Mann and Paulsen, 2005; Somogyi and Klausberger, 2005). However, we are still far from understanding the function of these oscillations. The computational richness and evolutionary conservation of network oscillations suggest that they are used in neural information processing. This series of three mini-symposia aims to discuss possible functions of network oscillations in relation to their computational roles.Key words: cognition; memory; olfaction; network; oscillation; synchronization