Jun 7, 2007 - This special issue of Trends in Neurosciences is dedicated to the INMED/TINS ... also display periodic Up and Down states. Destexhe, Cru-.
Editorial
TRENDS in Neurosciences
Vol.30 No.7
INMED/TINS special issue
Physiologic and pathologic oscillations Yehezkel Ben-Ari INSERM U29-INMED, Parc Scientifique de Luminy, BP 13. 13273 MARSEILLE Cedex 09, France
This special issue of Trends in Neurosciences is dedicated to the INMED/TINS meeting held in La Ciotat, France, in September, 2006, which focussed on physiological and pathological oscillations in the brain. The mechanisms that translate voltage- and transmitter-gated channel activity into behaviour rely on the generation of specific types of neural oscillation. Oscillatory electrical activity occurs in the brain when groups of neurons synchronize their firing activity. These oscillations are classified according to the neuron firing frequency: alpha oscillations are relatively slow (8–13 Hz) and are associated with closed-eye relaxation; beta oscillations (13 to 25 Hz) are commonly associated with normal waking consciousness; whereas gamma oscillations (25–40 Hz) have been associated with various aspects of perception and consciousness. Fries, Nikolic´ and Singer [1] review the generation of gamma oscillations, arguing that pyramidal neurons that fire strongly discharge early in the gamma cycle, thus providing a mechanism that relies on the conversion of amplitude to phase. This provides a way to rely more on coincident detection than on rate integration. Next, Jensen, Kaiser and Lachaux [2] unite to discuss the contribution of gamma to sensory binding. Relying on MEG, EEG and iEEG, they show that task-dependent gamma activity occurs during cognitive tasks in sensory and non-sensory areas. Various functions have been proposed for the slower theta rhythm (4–8 Hz), from sleep to perceptual integration. Maurer and McNaughton [3] discuss theta in relation to the mystery of place cells and ‘place field.’ They discuss a phase precession model in which the onset of theta indicates that the animal is in the current location but looks ahead during the rest of the theta cycle, announcing somehow its future location. They suggest that the precession originates in the entorhinal cortex and, subsequently, is enhanced by Hebbian plasticity in the network. The frequency range of delta waves is lower than that of theta (
