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Publications (55)
Objective: The integration of scientific research into medical education is a widely discussed topic. Most research training programs are offered on a voluntary basis. In Germany, it is mandatory to complete a doctoral thesis to obtain the academic title “doctor”. The reasons why students start a dissertation project and the influence of this proje...
Objective: In order to acquire the academic title “doctor” in Germany, it is essential to complete a dissertation. A high number of publications at German universities are based on medical dissertations. The reasons why some dissertations are successfully accomplished and why some are not completed – despite far-reaching consequences – have been ba...
The attitudes of medical students towards psychiatry and psychotherapy were examined considering the extent of their education, previous psychiatry experience, the evaluation of the course, their career intentions and socio-demographic variables.
Five hundred and eight medical students in their second, fifth, ninth and tenth semester completed a qu...
Successful and unsuccessful intention to learn words was assessed by means of event-related functional MRI. Eighteen patients with schizophrenia and 15 healthy control participants were scanned while being given two word lists to read and another seven to learn with immediate recall. Neural activation patterns were segregated according to whether w...
Depressive Störungen gehören zu den häufigsten Erkrankungen in der Psychiatrie: die Lebenszeitprävalenz schwerer depressiver Störungen beträgt 15-18 %. Der Häufigkeitsgipfel für die Ersterkrankung bei rezidivierender unipolarer Depression liegt in der Mitte des dritten Lebensjahrzehnts. 50 % der Patienten erkranken vor dem 40. Lebensjahr. Frauen er...
Neuroimaging studies have indicated involvement of left prefrontal cortex and temporal areas in verbal memory processes. The current study used event-related functional neuroimaging to compare encoding of subsequently recalled and not recalled words in high and low memory performers. Fifteen healthy volunteers were given lists of words to learn wit...
Anfang März 2004 berichteten sowohl die Fa. Janssen-Cilag als auch Lilly Deutschland in Rote Hand Briefen über ein erhöhtes Risiko zerebrovaskulärer Ereignisse bei Demenz-Patienten, die Risperidon bzw. Olanzapin erhalten hatten. Unter Risperidon traten in sechs Plazebo-kontrollierten Studien bei 33 von 989 Patienten (3,3 %) signifikant häufiger tra...
Regional cerebral blood flow (rCBF) and blood oxygenation level-dependent (BOLD) contrasts represent different physiological measures of brain activation. The present study aimed to compare two functional brain imaging techniques (functional magnetic resonance imaging versus [(15)O] positron emission tomography) when using Tower of London (TOL) pro...
Cortical reactions to rare task-related stimuli have been studied with electrophysiological methods in the assessment of the P300 component as well as in functional imaging studies with regard to oddball tasks. While functional magnetic resonance imaging studies using auditory stimuli have to deal with interference between auditory stimuli and scan...
The analysis of auditory deviant events outside the focus of attention is a fundamental capacity of human information processing and has been studied in experiments on Mismatch Negativity (MMN) and the P3a component in evoked potential research. However, generators contributing to these components are still under discussion. Here we assessed cortic...
For several years, a 68-year-old patient had been treated for a dementia of Alzheimer's type and finally admitted to a closed gerontopsychiatric nursing home. According to information from his relatives, he first developed psychotic symptoms 3 years prior to admission in our psychiatric department. Several months later, he developed a lack of drive...
For several years, a 68-year-old patient had been treated for a dementia of Alzheimer's type and finally admitted to a closed gerontopsychiatric nursing home. According to information from his relatives, he first developed psychotic symptoms 3 years prior to admission in our psychiatric department. Several months later, he developed a lack of drive...
This study aimed to identify the neural networks underlying automatic and active auditory deviant detection in six healthy subjects using positron emission tomography. Eight alternating blocks of standard and standard plus duration-deviant tones were presented while subjects performed a visual discrimination task. In an additional four blocks, the...
We used serial positron emission tomography (PET) to study training-induced brain plasticity after severe hemiparetic stroke. Ten patients were randomized to either task-oriented arm training or to a control group and scanned before and after 22.6 +/- 1.6 days of treatment using passive movements as an activation paradigm. Increases of regional cer...
In this article, the authors summarize results from imaging studies, analyzing the functional anatomy of motor sequence learning and timing. Emphasis is on the relationship between the cortical motor areas, the basal ganglia, and the cerebellum.
Event-related potential studies in man suggest a role for the supplementary motor area (SMA) in movement preparation, particularly when movements are internally generated. In a previous study combining PET with recording of movement-related cortical potentials, we found similar SMA activation and early pre-movement negativity during self-initiated...
We used serial positron emission tomography (PET) to study the evolution of functional brain activity within 12 weeks after a first subcortical stroke. Six hemiplegic stroke patients and three normal subjects were scanned twice (PET 1 and PET 2) by using passive elbow movements as an activation paradigm. Increases of regional cerebral blood flow co...
Cortical reorganization of motor systems has been found in recovered stroke patients. Reorganization in nonrecovered hemiplegic stroke patients early after stroke, however, is less well described. We used positron emission tomography to study the functional reorganization of motor and sensory systems in hemiplegic stroke patients before motor recov...
The present study investigated the involvement of the human cerebellum in the habituation of the acoustic startle response using PET. The startle response was elicited in seven young, healthy subjects by a tone presented via headphones. Startle responses were recorded from the right sternocleidomastoid muscle. Regional cerebral blood flow (rCBF) wa...
The role of the basal ganglia and cerebellum in the control of movements is unclear. We summarize results from three groups of PET studies of regional CBF. The results show a double dissociation between (i) selection of movements, which induces differential effects in the basal ganglia but not the cerebellum, and (ii) sensory information processing...
In der vorliegenden Übersichtsarbeit werden eine Reihe von Untersuchungen bei Patienten mit umschriebenen Kleinhirnerkrankungen und, mittels funktioneller bildgebender Verfahren, Untersuchungen bei Gesunden vorgestellt, die zeigen, dass das menschliche Kleinhirn an verschiedenen einfachen und komplexen motorischen Lernvorgängen beteiligt ist. Beisp...
Results of recent studies using positron emission tomography (PET) are presented demonstrating the involvement of the human cerebellum in simple and complex motor learning tasks in cerebellar patients and in healthy subjects. Classical conditioning of the limb flexion reflex (associative learning) and learning of sequences of single finger movement...
Using a positron emission tomography (PET) study it was shown recently that in migraine without aura certain areas in the brain stem were activated during the headache state, but not in the headache free interval. It was suggested that this brain stem activation is inherent to the migraine attack itself and represents the so called 'migraine genera...
We used positron emission tomography to study new learning and automatic performance in normal volunteers. Subjects learned sequences of eight finger movements by trial and error. In a previous experiment we showed that the prefrontal cortex was activated during new learning but not during during automatic performance. The aim of the present experi...
We used positron emission tomography to study motor learning by trial and error. Subjects learned sequences of eight finger movements. Tones generated by a computer told the subjects whether any particular move was correct or incorrect. A control condition was used in which the subjects generated moves, but there was no feedback to indicate success...
Recent PET studies performed in humans during migraine attacks revealed a 'spreading depression-like' oligemia in the occipital cortex during the aura phase and a region of increased blood flow in the brainstem during the headache phase. Animal models were established to test new migraine drugs. A number of 5-HT agonists, the so-called 'triptans',...
The performance of a motor task not only requires subjects to plan, prepare, and initiate but also to monitor how a movement is performed. We used positron emission tomography to examine to what extent the human cerebellum is involved in controlling motor output or sensory input from movements in normal subjects. In the first study, we compared the...
We used positron emission tomography (PET) to compare the contribution of the cerebellum and basal ganglia to the sensory guidance of movement. In one condition the subjects used a computer mouse to draw a series of lines on a computer screen (DRAW). In the second condition the same lines were presented to the subjects, and they had to track the li...
Changes of cerebellar blood flow were studied in normal humans using positron emission tomography (PET). A motor driven peg marked pairs of lines on subjects' right hands at different velocities. Subjects had to decide whether the second line was marked slower or faster than the first. Estimation of velocity (compared with control, i.e. presentatio...
During active and passive (driven by a torque motor) flexion and extension of the right elbow, regional cerebral blood flow (rCBF) was measured in six healthy, male volunteers using positron emission tomography and the standard H2(15)O injection technique. During active as well as during passive movements of the right elbow there were strong increa...
In its most general sense, cerebellar ataxia (irregular and disordered movements) presents as truncal ataxia, ataxia of stance and gait, limb ataxia, dysarthria and a variety of eye movement abnormalities. Damage of the flocculonodular lobe and lower vermis causes truncal ataxia and oculomotor signs. Lesions of the anterior lobe cause ataxia of sta...
We used positron emission tomography (PET) to localize a cerebellar timing function. Six healthy volunteers estimated time differences by comparing a test interval (defined by two tones) with a standard interval. In the timing condition, subjects lifted their right index finger if the test interval was shorter and their right middle finger if it wa...
Evidence from animal experiments shows that the brain stem is involved in the pathophysiology of migraine. To investigate human migraine, we used positron emission tomography to examine the changes in regional cerebral blood flow as an index of neuronal activity in the human brain during spontaneous migraine attacks. During the attacks, increased b...
The energy metabolism of the adult human brain almost completely depends on glucose. The functional coupling of regional cerebral blood flow and local cerebral glucose metabolism has been established in a wide range of experiments using autoradiographic techniques in rats, cats, and monkeys as well as double-tracer techniques in humans. Glucose uti...
Neuere Entwicklungen auf dem Gebiet der nicht-invasiven bildgebenden Methoden bieten die Möglichkeit, neben der Morphologie auch die Hirnfunktion abzubilden. Diese Methoden des “funktionellen brain mappings” basieren auf der Tatsache, daß physiologische Veränderungen der Hirnfunktion unter Aktivierung des visuellen, motorischen und anderer neuronal...
The brainstem mediated inhibitory reflex of the m. temporalis was investigated on average 3 days after the accident in 61 patients (f = 36; m = 25; mean age = 28 years +/- 9 SD) who presented an acute cervico-cephalic syndrome with posttraumatic headache and neck pain following acute whiplash injury but without neurological deficits, bone injury of...
In einer prospektiven Studie untersuchten wir bei 451 Patienten die Arteria vertebralis mit der extrakraniellen CW-Doppler-Sonographie (Atlasschlingenbereich), der subokzipitalen transkraniellen Doppler-Sonographie sowie der farbkodierten Duplexsonographie. Die auffälligen Vertebralarterienbefunde (Hypoplasie, Stenose, Verschluß) in der farbkodiert...
The specific binding of tritiated muscimol to gamma-aminobutyric acid (GABA) receptor sites was studied in distinct brain areas of female rats during different endocrine states. In diestrous rats with intact ovaries the highest receptor densities were found in the cortex (10.24 pmol/mg protein) and the lowest concentrations in the mediobasal hypoth...
3 alpha-Hydroxy-5 alpha-pregnan-20-one (HPO) is a progesterone metabolite which exhibits narcotic properties at high concentrations by interactions with the receptor for gamma-aminobutyric acid (GABA). The present investigation characterized low-dose effects of HPO on GABAA receptor binding, by determining the allosteric properties of HPO on the in...
The distribution of GABAA receptor sites was studied in female and male rat brain by an improved in vitro binding assay using 3H-muscimol and carefully washed membrane fractions. The binding studies revealed a single class of binding sites exhibiting the properties of GABAA receptors. The specific binding of 3H-muscimol was measured in four brain a...
