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Abstract

While neurons communicate, they consume energy and oxygen, which is supplied by
the blood stream. Changes in local cerebral blood flow and in oxygen consumption
can be measured using functional magnetic resonance imaging (fMRI). This technique is one of the most frequently used tools to non-invasively monitor neuronal activity in the human. However, the mechanisms that are coupling the neuronal activity with the vascular response are not well understood so far. Additionally, there is only insufficient quantitative anatomical data on the microvascular system. For example, the regional distribution of the smallest vessels (capillaries) that are crucial for the exchange of gases and metabolites is still unclear. Quantitative data about the brain's microvasculature could provide new insight into the regulatory properties and dynamics of the neurovascular system and may lead to a better interpretation of the non-invasive functional imaging signals. The goal of my
PhD project is a complete quantitative and qualitative description of the angioarchitecture of the macaques visual cortex. As part of the thesis project I have
quantified the vascular density in the visual cortex of the macaque monkey in an
immunohistochemical and histological approach. So far, we were able to show the
characteristic vessel distribution across the different cortical layers and to detect
significant differences between the primary and the higher order visual cortices.
Therefore, caution is advised when in a vision-based task the functional signals from
different regions of the visual cortex are compared.