BMBF-Bernstein-Gruppe: "Components of cognition: small networks to flexible rules". Teilprojekt "Ongoing dynamics of neocortex: amplitude and phase modulations"

The motivation for our project is to better understand the neuronal dynamics in cortical networks. This is a prerequisite for the design of new brain-machine interfaces and the implementation of cortical neuroprostheses. A key issue in this topic is the understanding of how input into cortical networks is processed. The project aims at integrating experimental and theoretical approaches to unravel the mechanisms underlying amplitude and phase modulation in neocortical activity exploiting the complementary expertises from three domains: human scalp electrophysiology (Herrmann), human intracranial electrophysiology (Hinrichs), and animal intracranial electrophysiology (Ohl).Some of the questions to be addressed are:· Is bottom-up modulation of cortical activity after sensory input predominantly reflected in the phase organization and top-down modulation rather in amplitude parameters?· What are intracortical and thalamocortical contributions to cortical oscillations?· How do classical parameters of single unit activity (spike timing, spike probability, correlations, etc.) relate to classical parameters of neuronal mass activity (amplitude and phase structure of LFP and EEG)?· We aim at testing hypotheses on the mechanisms underlying modulation of amplitude and phase structure of EEG by predicting effects of pharmacological manipulations (e.g. selective facilitation or inhibition of transmitter systems) in the animal model. The predictions are arrived at using a biologically plausible model of the cortical network.