BMBF-Bernstein-Kooperation: "Improving interpretability of fMRI data by registration with simultaneously acquired separate components of the hemodynamic response by optical methods and neuronal activity by electrophysiology". Teilprojekt "Cortico-striatal

The neuronal interplay between cortical and striatal systems is believed to play a central role in the organization of learning. However, a number of critical aspects of this hypothesized interplay pertaining to its precise role in learning and the neural mechanisms for its implementation are still unknown. These aspects include the potential differentiation of cortico-striatal interplay between learning situations that include the option for behavioural strategies of improving the present state (operant learning) and those that do not (classical conditioning). Also, the temporal relationships between neural activity and striatum, respectively, with their implications for resolving the processing hierarchy in the cortico-striatal interplay during such learning situations are presently not well understood. A third aspect is the unclear role of cortico-striatal interplay in cortico-cortical information transfer as it appears in crossmodal learning transfer paradigms.The proposed project aims at a more fundamental understanding of the role and mechanisms of the cortico-striatal interplay in learning situations by combining suitable behavioral paradigms with simultaneous registration of brain activity from cortex and striatum. Brain activities will be derived from measuring electrophysiological recording, optical recording of intrinsic signals (ORIS) and voltage-sensitive dyes (VSD) as well as functional magnetic resonance imaging (fMRI) (in collaboration with TP1). While electrophysiological recording will provide access to both cortex and striatum this method is insufficient with respect to spatial sampling. ORIS and VSD, while providing sufficient spatial resolution, are limited to surface brain structures and cannot be used to access striatum. Here, electrophysiology and optical imaging will be complemented by fMRI which allows observation of this deep brain structure. Our theoretical work (in close collaboration with TP2A,B) will include the transformation of 3D electrophysiological data on intracortical current source density distributions to 2D data on the BOLD response observed on the cortical surface with ORIS.