The amygdaloid complex is involved in the mediation of emotional components of behaviour and related clinical symptoms. While numerous studies addressed the synaptic substrates of amygdaloid function in animal models, not a single study is available on synaptic network activity in the human amygdala. Therefore we used slices of amygdaloid tissue obtained from epilepsy surgery (n=5) and monitored electrical activity of the lateral nucleus (LA) using electrophysiological and optical (RH 795) multiple site recording techniques. Upon electrical microstimulation within the LA, population activity was evoked that propagated from the stimulation to more distal sites. Both field potential and optical recordings revealed a preference in the spread of activity from dorsolateral to ventromedial sites in the LA. Directed propagation (DP) was evident upon electrical stimulation at different strengths (threshold to supra-threshold), and during epileptiform activity that occurred spontaneously or in 0-Mg2+ solution. Application of the GABAA receptor antagonist bicuculline (10mM) interfered with DP, in that the spread of electrical activity was symmetrical. It is concluded that GABAergic mechanisms shape the propagation of synaptic activity in the human LA.