BSCDB Spring Meeting: Molecular & Cellular Basis of Neuroconnectivity location:Leuven, Belgium date:May 4-6, 2006
Various techniques have been applied in the past to study the neocortical parcellation into functionally specialized areas. In this study, we introduced a novel approach in an
attempt to map anatomical subdivisions in the mammalian cortex unambiguously.
We compared the protein expression profiles of the primary visual (V1) and somatosensory area (S1) of mouse using 2-D DIGE and mass spectrometry to screen for new potential area-specific protein markers. Prior to manual collection of V1 and S1, we stained adjacent sections for cytochrome oxidase to use as a guide to avoid the regions of inter-areal borders, this in order to absolutely avoid contamination of the protein samples with proteins of other brain regions. Twenty-three proteins were found to be significantly differential between V1 and S1, of which 56% appeared more abundant in V1.
We selected creatine kinase, brain subtype (CKB) as potential areal marker protein, since this protein also appeared to be differential in a comparable study on cat
neocortex. CKB plays a key role in the energy metabolism of tissues with fluctuating energy requirements. It was found to have a S1/V1 ratio of 1,67 +/- 0,43. In situ hybridisation is a high-resolution method to screen total mouse brain for area-specific expression differences at the mRNA level. This validation method confirmed the differential expression of CKB between V1 and S1 on mouse frontal and sagittal sections. S1 has an intense signal in cortical layers III and V, where the highest signal in
V1 can be found in layers II, IV and VI. This difference in lamination pattern enables us to distinguish with certainty different areas in not only the somato-sensory and visual
system, but also in the auditory and motor system of the mouse. We identified CKB as a valuable marker for the parcellation of mammalian neocortex.