Spontaneous epileptic activity resembling spike wave discharges (SWD) characteristic of Generalized Absence (GA) epilepsy was induced in rat thalamocortical (TC) slices by incubating the slices in low-Mg2- artiﬁcial cerebrospinal fluid (ACSF) Extracellular field potentials were recorded in the cortex and thalamus to determine the effects of the broad spectrum metabotropic glutamate receptor (mGluR) agonist  trans- (1S  3R)-1-Amino-1  3-cyclopentanedicarboxylic acid (ACPD)  ACPD elicited concentration dependent effects on the duration of SWD