Dopamine modulates cortical circuit activity in part through its actions on GABAergic interneurons, including increasing the excitability of fast-spiking interneurons. Though such effects have been demonstrated in single cells, there are no studies that examine how such mechanisms may lead to the effects of dopamine at a neural network level. In this study, we investigated the effects of dopamine on synchronization in two simulated neural networks; one biophysical model composed of Wang-Buzsaki neurons and a reduced model with theta neurons. In both models, we show that parametrically varying the levels of dopamine, modeled through the changes in the excitability of interneurons, reveals an inverted-U shaped relationship, with low gamma band power at both low and high dopamine levels and optimal synchronization at intermediate levels. Moreover, such a relationship holds when the external input is both tonic and periodic at gamma band range. Together, our results indicate that dopamine can modulate cortical gamma band synchrony in an inverted-U fashion and that the physiologic effects of dopamine on single fast-spiking interneurons can give rise to such non-monotonic effects at the network level.
Model Type: Realistic Network
Cell Type(s): Abstract Wang-Buzsaki neuron; Abstract theta neuron
Transmitters: Dopamine
Model Concept(s): Synchronization
Simulation Environment: XPPAUT
Implementer(s): Ermentrout, Bard [bard_at_pitt.edu]; Komek, Kubra [kkomek at andrew.cmu.edu]
References:
Kömek K, Bard Ermentrout G, Walker CP, Cho RY. (2012). Dopamine and gamma band synchrony in schizophrenia--insights from computational and empirical studies. The European journal of neuroscience. 36 [PubMed]