Online supplementary material to

ABSTRACT of the Neuroscience paper

Theta frequency oscillation of the septo-hippocampal system has been considered as a prominent activity associated with cognitive function and affective processes. It is well documented that anxiolytic drugs diminish septo-hippocampal oscillatory theta activity contributing to their either therapeutic or unwanted side effects. In the present experiments we applied a combination of computational and physiological techniques to explore the functional role of GABAA receptors in theta oscillation. In electrophysiological experiments extracellular single unit recordings were performed from medial septum/diagonal band of Broca (MS/DB) with simultaneous hippocampal (CA1) EEG recordings from anesthetized rats. Neurotransmission at GABAA receptors were modulated by means of pharmacological tools: the actions of the GABAA receptor positive allosteric modulator diazepam and inverse agonist/negative allosteric modulator FG-7142 were evaluated on septo-hippocampal activity. Systemic administration of diazepam inhibited, whereas FG-7142 enhanced theta oscillation of MS/DB neurons and hippocampal EEG theta activity. In parallel to these experimental observations, a computational model has been constructed by implementing a MS/DB GABA neuron model with a three-neuron population hippocampal CA1 model (including oriens and basket interneurons and pyramidal cells; each cell type modelled by multicompartmental techniques). This connectivity made the network capable of simulating the responses of the septo-hippocampal circuitry to the modulation of GABAA transmission, and the presently described computational model proved suitable to reveal several aspects of pharmacological modulation of GABAA receptors. In addition, computational findings indicated different roles of distinctively located GABAA receptors in theta generation.

Purpose of these pages

These pages were created to supply the Reader with details: equations, parameter ranges, computer simulations scripts used for simulations published in the article. Scripts are written for the GENESIS simulator program and are available piece-by-piece from cell description pages or as a single tarball from the download page.

We suggest to first browse through the given references as they are of great importance in the understanding of our model. By clicking on different parts of the image below equations and parameters describing the selected component of the model are available.