Primary and Secondary Hypothalamus and Brain Stem Lesions. In: Dietz H, Brock M, Klinger M, editors. Extra-Intracranial Vascular Anastomoses Microsurgery at the Edge of the Tentorium. Berlin: Springer Berlin Heidelberg; 1985. pp. 217-53. [DOI: 10.1007/978-3-642-70603-5_37]

Function tests on the neuroendocrine hypothalamo-pituitary system following acute midbrain syndrome, with special reference to computertomographical and magnetic resonance imaging results

Seventeen patients underwent a neuroendocrinological function test at a mean 6.3 years following a severe craniocerebral trauma (CCT) accompanied by midbrain syndrome. An insulin hypoglycaemia test (IHT) and the combined pituitary anterior lobe test (CPALT) were applied. Whereas the IHT as maximum stimulator of the hypothalamo-pituitary system (HPS) showed an adequate reserve capacity, the CPALT yielded a partial limitation of the secretion dynamic in the somatotropic, adrenocorticotropic axis as well as a dysfunction in the FSH secretion. Neuroradiological tests could not establish substantial injury in the regio hypothalamica in any patient.

Biomathematics of intracranial CSF and haemodynamics. Simulation and analysis with the aid of a mathematical model

A mathematical model of the isolated intracranial system including autoregulation of cerebral blood flow with the aid of a variable cerebrovascular resistance is described. The rate of formation of cerebrospinal fluid is assumed to depend on the regional blood flow through the choroid plexuses. This model is extended by cardiovascular components including the left ventricle of the heart, the aorta and the peripheral resistance. Additionally the model contains control circuits to simulate the short-time behaviour of the blood pressure regulation with the aid of the baroreceptor reflex. Disturbances of central regulation of blood pressure are simulated depending on changes of the regional blood flow through the brain stem. The application of the model is demonstrated by the analysis of the influence of arterial blood pressure upon the intracranial pulse pressure relationship (PPR) and upon the pressure response to a volume pressure test. Theoretical considerations and simulations reveal an opposite effect of arterial blood pressure (ABP) and its amplitude upon PPR. The ICP amplitude rises with decreasing ABP or increasing ABP amplitude. Breakpoints and other deviations from a linear PPR over the whole ICP range are studied by the analysis of the transfer function. The application of the model concerning parameter estimation methods is demonstrated and discussed. Simulations of rhythmic phenomena with the aid of the extended model point out possible approaches to quantitative descriptions of disturbances of central regulation.

Plasticity of the central nervous system--a neurosurgeon's experience of cerebral compensation and decompensation

Cerebral plasticity constitutes one of the most decisive factors in recovery and readaptation after cerebral lesions. In contrast to the considerable progress in current studies on normal neuronal plasticity including the idea of "l'homme neuronal", the concept of plasticity postulated by Albrecht Bethe in 1929 received little attention. The author, as a neurosurgeon, has tried to describe cranial morphological plasticity, morphological and functional plasticity in infantile encephalopathies and especially in hemiatrophic lesions. It is supposed that a true morphological substrate exists due to compensatory hyperplasia of the uninvolved hemisphere. Modern neurosurgical techniques have demonstrated that the functional plastic capacity is much larger than has been supposed, even in the elderly. Some aspects of the mechanisms of compensation and decompensation of cortical and subcortical structures as well as of the central regulation systems are discussed. The full extent of the amazing recovery and functional reorganization is reached by plastic capacity, personal motivation, adequate training and sufficient time. The contribution ends with an exposition of a personal philosophy concerning psycho-somatic dualism, the body-mind problem, the future of the human brain and the ethical outlook, based on the progressive biological evolution of the basal neocortex and the immanent functional development (H. Spatz).