Clinical Neuroscience

[THE ROLE OF MICRO-AROUSALS IN THE REGULATION OF SLEEP]

HALÁSZ Péter

JULY 30, 2006

Clinical Neuroscience - 2006;59(07-08)

[This work give a short account about a three decades research of the sleep microstructure. The studies, executed by the Strassbourg, Budapest and Parma schools, paved the way of exploring the participation of micro-arousals in the sleep regulation. It was shown that micro-arousals, not leading to instant arousal but influencing the later course of sleep are weaved into the network of sleep. A certain class of microarousals differs from the traditional desyncronisation-type and in a paradox way result a rebound like mobilisation of sleeplike activity with deltas and K-complexes. The desynchronisation- and synchronisation-type micro-arousals show different distribution along the sleep cyclicity and may play different role in sleep regulation. On the basis of the studies dealing with micro-arousals we can assume that beside the traditional long time constant, brain stem driven tonic chemical regulation, an other phasic regulation, with shorter time constant, underlied by the micro-arousals, also exist. This kind of phasic regulation makes sleep flexible and possible to adapt the actual sleep course to the inner and outer demands. An other important role of micro-arousals in pathological sleeps is to provide a gate for the different pathological events, pinpointing the key-points where these events could be expected in the sleep process.]

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Clinical Neuroscience

[THE IMPACT OF MOOD ALTERATIONS ON CREATIVITY]

JANKA Zoltán

[Basic elements of artistic (and other) creativity are the technical-professional skill and knowledge, the special talent and ability and the willingness or motivation; one of which being absent results in partially realised creativities like juvenile, frustrated or abandoned types, respectively. Psychometric scales have been developed to measure everyday and eminent creativities, which show that creativity correlates with higher psychoticism, impulsivity and venturesomeness scores and with lower neuroticism and conformity scores of the personality test employed in a general population. Among the psychological components of creativity are the cognitive processes, mood, motivation, and personality traits. Regarding mood, a theory of “inverted U” has been proposed as elevation of mood facilitates creativity to a certain point after what extreme increase has an adverse effect on achievement. Analysing psychopathology and creativity among various professions, higher rates of psychopathology, especially affective symptoms, have been found in art-related professions. Examples of immortal poets, writers, painters, sculptors and composers, having created invaluable cultural treasures for the mankind, illustrate that many of them showed signs of mood alterations (unipolar or bipolar affective disorder spectrum) which were expressed in their artistic products.]

Clinical Neuroscience

[PARALLEL PROCESSING OF VISUAL INFORMATION]

BENEDEK György, JANÁKY Márta, BENEDEK Krisztina, KÉRI Szabolcs

[This is a survey on the function of parallel visual pathway with a special emphasis on its clinical implications. It is based on data in the literature and own results of our group. The paper primarily deals with the X, Y, W pathways and by the magnocellular, parvocellular and koniocellular visual pathways characterized by cells of various size as well as by nerve fibers of various thickness. Electrophysiological, microelectrode recording of single-unit activity makes the distinction between the pathways available in animal modell. Much more difficulties arise if we intend to characterize the pathways in humans or to detect the selective damage of one of these pathways in patients. The non-invasive diagnostic methods that could be used in the diagnosis are detailed here, too. Finally, the neurological, ophtalmological and psychological diseases are discussed in which a selective damage of any visual pathway is suspected. Summing it up, the survey provides evidences for the introduction of the novel concept of parallel pathways into the diagnostic aspects of ophthalmology, neurology and psychiatry.]

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TÚRY Ferenc, LUKÁCS Liza

Clinical Neuroscience

[THE AUGMENTATION OF CLOZAPINE TREATMENT WITH ELECTROCONVULSIVE THERAPY]

GAZDAG Gábor, KOCSIS-FICZERE Nárcisz, TOLNA Judit

[Objectives - The assessment, in terms of safety and efficacy, of augmenting clozapine monotherapy, as well as combined psychopharmacotherapy involving clozapine, with electroconvulsive therapy (ECT). Method - Reviewed were the charts of patients who received clozapine-ECT treatment in the Department of Psychiatry and Psychotherapy of Semmelweis University between November 1999 and December 2003. Results - During the studied period there were altogether 43 patients treated with the combination of clozapine and electroconvulsive therapy. In the schizoaffective group, the values for post-electroconvulsive therapy CGI were significantly lower than either in the catatonic (Z=-3.72, p<0.01) or in the hebephrenic (Z=-3.17, p<0.01) group. Among the groups created on the basis of the number of augmentation strategies utilized, the clozapine+3 group consisted of patients significantly older than the clozapine+1 group (Z=2.45, p=0.01). In the clozapine monotherapy group, the values for post-electroconvulsive therapy CGI were significantly lower than in any of the groups that had received a combination of augmentations (monotherapy-1 augmentation: Z=-3.01, p<0.01; monotherapy-2 augmentation: Z=-2.89, p<0.01; monotherapy- 3 augmentation: Z=-2.41, p=0.01). Conclusions - According to our examinations, the augmentation of clozapine treatment with electroconvulsive therapy should be tried primarily on schizoaffective patients, in case the clozapine monotherapy is ineffective. The simultaneous use of different augmentation strategies is expected to increase only the side effects not the efficacy of the treatment.]

Clinical Neuroscience

[AIDS-RELATED TOXOPLASMA-ENCEPHALITIS PRESENTING WITH ACUTE PSYCHOTIC EPISODE]

ILNICZKY Sándor, DEBRECZENI Róbert, KOVÁCS Tibor, VÁRKONYI Viktória, BARSI Péter, SZIRMAI Imre

[The most frequent neurological manifestations of the Acquired Immunodeficiency Syndrome- (AIDS) are Cerebral Toxoplasmosis, Primary Central Nervous System Lymphoma (PCNSL), Progressive Multifocal Leukoencephalopathy (PML) and AIDS-encephalitis (AIDS-dementia complex, multinucleated giant cell encephalitis, HIV-encephalopathy). Neurological complications usually occur in the advanced stages of the disease, and they are uncommon in the beginning as presenting illness, but may result in lifethreatening condition or in death. Rarely the disease presents as a neuropsychiatric illness in an undiagnosed AIDS patient, delaying a proper diagnosis. We present the case of a 34 years old patient treated for AIDS-related Toxoplasma-encephalitis in our department. His illness started as an acute psychosis followed by rapid mental and somatic decline, leading to death in three months. His HIV-seropositivity was not known at his admission, and the extraneural manifestations were slight. The diagnosis was established by serology, imaging methods and histopathological investigation. After presenting the medical history and results of autopsy studies of the patient we discuss the problems of the differential diagnosis, especially regarding the findings of the imaging methods.]

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Clinical Neuroscience

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[A growing body of evidence suggests that sleep plays an essential role in the consolidation of different memory systems, but less is known about the beneficial effect of sleep on relational memory processes and the recognition of emotional facial expressions, however, it is a fundamental cognitive skill in human everyday life. Thus, the study aims to investigate the effect of timing of learning and the role of sleep in relational memory processes. 84 young adults (average age: 22.36 (SD: 3.22), 21 male/63 female) participated in our study, divided into two groups: evening group and morning group indicating the time of learning. We used the face-name task to measure relational memory and facial expression recognition. There were two sessions for both groups: the immediate testing phase and the delayed retesting phase, separated by 24 hours. 84 young adults (average age: 22.36 (SD: 3.22), 21 male/63 female) participated in our study, divided into two groups: evening group and morning group indicating the time of learning. We used the face-name task to measure relational memory and facial expression recognition. There were two sessions for both groups: the immediate testing phase and the delayed retesting phase, separated by 24 hours. Our results suggest that the timing of learning and sleep plays an important role in the stabilizing process of memory representation to resist against forgetting.]

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Clinical Neuroscience

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Over the second half of the 19th century, numerous theories arose concerning mechanisms involved in understanding of action, imitative learning, language development and theory of mind. These explorations gained new momentum with the discovery of the so called “mirror neurons”. Rizzolatti’s work inspired large groups of scientists seeking explanation in a new and hitherto unexplored area of how we perceive and understand the actions and intentions of others, how we learn through imitation to help our own survival, and what mechanisms have helped us to develop a unique human trait, language. Numerous studies have addressed these questions over the years, gathering information about mirror neurons themselves, their subtypes, the different brain areas involved in the mirror neuron system, their role in the above mentioned mechanisms, and the varying consequences of their dysfunction in human life. In this short review, we summarize the most important theories and discoveries that argue for the existence of the mirror neuron system, and its essential function in normal human life or some pathological conditions.

Clinical Neuroscience

Neuroscience highlights: Main cell types underlying memory and spatial navigation

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Interest in the hippocampal formation and its role in navigation and memory arose in the second part of the 20th century, at least in part due to the curious case of Henry G. Molaison, who underwent brain surgery for intractable epilepsy. The temporal association observed between the removal of his entorhinal cortex along with a significant part of hippocampus and the developing severe memory deficit inspired scientists to focus on these regions. The subsequent discovery of the so-called place cells in the hippocampus launched the description of many other functional cell types and neuronal networks throughout the Papez-circuit that has a key role in memory processes and spatial information coding (speed, head direction, border, grid, object-vector etc). Each of these cell types has its own unique characteristics, and together they form the so-called “Brain GPS”. The aim of this short survey is to highlight for practicing neurologists the types of cells and neuronal networks that represent the anatomical substrates and physiological correlates of pathological entities affecting the limbic system, especially in the temporal lobe. For that purpose, we survey early discoveries along with the most relevant neuroscience observations from the recent literature. By this brief survey, we highlight main cell types in the hippocampal formation, and describe their roles in spatial navigation and memory processes. In recent decades, an array of new and functionally unique neuron types has been recognized in the hippocampal formation, but likely more remain to be discovered. For a better understanding of the heterogeneous presentations of neurological disorders affecting this anatomical region, insights into the constantly evolving neuroscience behind may be helpful. The public health consequences of diseases that affect memory and spatial navigation are high, and grow as the population ages, prompting scientist to focus on further exploring this brain region.