CBBS-ScienceCampus

Project group 7 

The hippocampus plays important roles in the consolidation of learning directed processes. Considerable evidence suggests that dopamine is involved in modulating the consolidation or retrieval of memory. Dopaminergic neurons of the midbrain are the major source of dopamine in the brain. Hippocampal activity is indirectly linked to the activity of dopaminergic neurons in the midbrain (ventral tegmental area and substantia nigra; VTA-SN) and controls by that the function of various structures in the mesolimbic system, such as the nucleus accumbens, the amygdala, the medial prefrontal cortex and eventually the hippocampus itself. Electrical stimulation of one major hippocampal output system, the fimbria-fornix, in combination with functional magnetic resonance imaging (fMRI) or fast scan cyclic voltammetry (FSCV) will reveal how altered hippocampal activity drives mesolimbic dopaminergic activity and how this in turn modifies hippocampal activity.

Thus, in this project we study how activation of the hippocampus-VTA loop affects brain wide neuronal networks. For that, a multimodal imaging approach is employed to examine global and local changes in neuronal activities that occur during defined electrical hippocampal fimbria-fornix stimulation in the rat brain. Changes in global neuronal network activity during electrical stimulation of the fimbria fibres will be visualized by fMRI and local neurochemical changes will be monitored by FSCV. Engineered designer receptors exclusively activated by designer drugs (DREADD) will be used to selectively silence dopaminergic neurons in the VTA to examine how a disturbed hippocampal-VTA loop modifies functional interactions of the hippocampus with various subcortical and cortical structures.