“…Neurons can communicate with each other either synaptically, electrically through gap junctions, or both (Tamás et al, 1998;Galarreta and Hestrin, 1999;Fukuda and Kosaka, 2000;Thomson et al, 2002). Electrical coupling has been observed chiefly among neurons of the same interneuron class (Galarreta and Hestrin, 1999;Tamás et al, 2000;Deans et al, 2001;Szabadics et al, 2001;Beierlein et al, 2003;Blatow et al, 2003;Galarreta et al, 2004;Mancilla et al, 2007;Fanselow et al, 2008) and has been postulated to promote fast spike synchronization (Traub et al, 2001;Gibson et al, 2005;Hughes and Crunelli, 2007;Mancilla et al, 2007). A recent in vitro study, however, suggested that millisecond synchrony between inhibitory interneurons can be equally well achieved by chemical synapses (Hu et al, 2011).…”