|dc.description.abstracteng||The bipolar and the unipolar disorder that are both part of affective disorders belong to those psychological diseases which occur the most often after substance-related addictions and panic disorders. According to epidemiological studies there is an increased incidence of this illness, a high recurrence rate as well as accompanying symptoms, thus the bipolar disorder is of great importance for the medical and socio-economical field.
The pathophysiological basis of this disease is not yet completely understood, and still subject to further research. The importance of the hippocampus as part of the limbic system has been disregarded for a respectable amount of time. Preceding studies, however, prove that there is undoubtedly a connection with changes of the hippocampus, which plays a significant role with regard to memory formation, affect processing, and the bipolar disorder.
The aim of this dissertation – which is to our knowing the first stereological analysis of the human posterior hippocampus - is to find a potential correlate on a cellular level within the subregions CA1 up to CA4 as well as the subiculum. To conduct the experiment, pieces of brains, which belong to Magdeburg's collection, were extracted from 10 samples and 8 patients who suffered from bipolar disorders, and were then analyzed by using a valid stereological method. Apart from the structural volume, the number of cells, the cell density, and their volume were determined. The latter, however, was not taken into consideration during the evaluation due to an insufficient intra-rater reliability.
Our postmortem study shows that patients with a bipolar disorder have an increased number of cells as well as a higher cell density with respect to neurons and oligodendrocytes within several subregions of the posterior hippocampus. Since the volume of those regions has not been subject to any changes, though, we conclude that there is a disorder concerning the neuronal plasticity. Our observation demonstrates once again the importance of the hippocampus during the earlier pathogenesis of bipolar disorders. Consequently, this implies the need for further research – while also considering the functional subdivision of the hippocampus and its importance for the anterior affect processing - by taking the hippocampus as a whole into account.||de