Dissection of Synchronous Population Discharges In Vitro

Abstract

Synchronous population activities are generated by neuronal circuits of most brain regions. Distinct behavioural states are associated with the emergence of oscillations such as the theta and gamma rhythms of the hippocampus (Bragin et al., 1995; Buzsaki et al., 1983; Leung, 1992). Sleep phases are recognized by distinct rhythmic synchronous patterns (Steriade and Timofeev, 2003). Neuronal synchrony is observed during perinatal development, in many brain structures including the hippocampus (Leinekugel et al., 1998), retina (Meister et al., 1991) and spinal cord (O’Donovan, 1999). Pathological neuronal synchronization is associated with several disease states including Parkinson (Levy et al., 2000) and the epilepsies (Jefferys, 1994). This list shows that synchrony is ubiquitous in the nervous system, observed in many areas with different spatial and temporal properties and physiological or pathological correlates. In this review, we will focus on epileptiform and allied activities generated in the hippocampal formation attempting to show how different techniques and methods of analysis have propelled recent progress.