Virtual slice simulation of resonance in a layered cortical model

TitleVirtual slice simulation of resonance in a layered cortical model
Publication TypeConference Paper
Year of Publication2008
AuthorsNeymotin, SA., Uhlrich DJ., & Lytton WW.
Conference NameSociety for Neuroscience

We explored oscillations of a 6 layer visual cortex virtual slice of 1620 cells and 558,464 synapses. Cells were modeled using complex rule-based units with myriad features including fast and slow adaptation and voltage-sensitive NMDA activation. Interlaminar synaptic densities were approximated from anatomy and prior simulations in the literature. The virtual slice setup permitted exploration of responses with interactive manipulation of synaptic strength parameters. Synaptic strengths were gradually increased until a response was elicited that involved all layers without producing overactivation (depolarization blockade) in any. Basic response involved 2-4 oscillatory cycles at 10-25 Hz. Activity spread was dominated by the major feedforward pathway from layer 4->2/3->5 with fast 2/3-4 antiphase oscillations within the slow oscillatory envelope (Fig. 1). NMDA strength augmentation produced a continuous oscillation while disinhibition did not substantially increase activity duration. (Fig. 1. A. Raster plots of excitatory cells in 4 layers of model cortex after 20 ms stimulation to layers 4 and 6. Layer 5 has both regular firing (5R) and bursting (5B) cells B. Color coded representative single unit voltages.)