Rapid temporal modulation of synchrony in cortical interneuron networks with synaptic plasticity

The synchrony of neurons in the extrastriate visual cortex is modulated by selective attention even when there are only small changes in firing rate (Fries et al., Science 291 (2001) 1560). We used Hodgkin-Huxley type models of cortical neurons to investigate the mechanism by which the degree of synchrony can be modulated independently of changes in firing rate. The synchrony of local networks of model cortical interneurons interacting through inhibitory synapses with short-term synaptic plasticity was modulated on a fast timescale by selectively activating a fraction of the interneurons. We found that facilitation enhanced the synchrony of the system whereas depression reduced it. In systems with synaptic plasticity, the synchrony modulation was accompanied by larger changes in the firing rate. (c) 2004 Elsevier B.V. All rights reserved.