Karl Zilles: “What transmitter receptors can tell us about cortical organization”
CiNet 1F Conference Room
Institute of Neuroscience and Medicine
Research Centre Jülich
Department of Psychiatry
Psychotherapy and Psychosomatics
RWTH University Aachen
Transmitter receptors represent key molecules of signal transmission in the nervous system. We know a lot about their structure and functions at the molecular level, but how can we understand the role of receptors at a much higher scale, i.e. the regional level (e.g., cortical areas, functional neural systems) in the human brain? At this scale their properties at the molecular level provide necessary, but not sufficient knowledge for understanding their role in the context of the complex circuitry of the brain. Therefore, a top-down approach is necessary to analyze the expression of receptor at a much higher organizational level.
It will be shown that multiple receptor types of all classical transmitter systems are expressed at different but system- or region- specific densities in different neural networks. The quantitative multiple receptor pattern, which is the balance between the densities of multiple receptor within one brain region (“receptor fingerprint”), is characteristic for each brain region, for each modality (visual versus somatosensory versus auditory cortices), similar in regions of the same functional system (e.g., language-related cortical areas), and differs between such large-scale neural system. Examples of changes in receptor expression caused by neurological a psychiatric disorders will also be demonstrated. Finally, a first approach to a multimodal and multiscale brain map, which integrates microscopic cyto- and receptorarchitectonic data as well as magnetic resonance imaging data in a common reference brain will be presented. This map provides a bridge between the scales from microscopic to meso- or macroscopic resolution, and a reference frame for anatomically and neurochemically precise interpretation of structural and functional MRI or PET data.