Neurochemical substrates and neuroanatomical generators of the event-related P300

The present review focuses on the current knowledge of the neurochemical processes and neuronal structures involved in the generation of P300. The increasing knowledge in this area facilitates the physiological interpretation of P300 findings as well as the link between P300 research and other research findings in biological psychiatry. Concerning the question of neurochemical substrates, the glutamatergic, GABAergic, cholinergic, noradrenergic, dopaminergic and serotonergic influences on P300 are reviewed. The knowledge of the generating structures of P300 is summarized from intracranial studies, magnetoencephalographic investigations, lesion and animal studies

Lithium-induced EEG changes in patients with affective disorders

In 12 patients with affective disorders (ICD-10: F31, F32, F33), EEGs were recorded before and after 4.4 months of lithium treatment. Effects of lithium on the EEG were analyzed by power spectral analysis controlled for vigilance. We found (1) an increase in relative power in both delta and theta band which was related to the lithium plasma level, (2) a decrease in relative alpha power especially at occipital leads and (3) a reduction of the dominant alpha frequency. The changes in relative power were more pronounced in the right hemisphere, which is in contrast to the hypothesis of a site-specific localization of lithium effects only in left anterior regions. Copyright (C) 2000 S. Karger AG,Basel

Periodic motor impairments in a case of 48-hour bipolar ultrarapid cycling before and under treatment with valproate

Motor impairments of psychiatric patients can be assessed with digital recordings of handwriting tasks. The investigation of patients with bipolar affective disorders differentiates intraindividual changes related to the patient's fluctuating affective states. An unmedicated 67-year-old male with 48-hour bipolar ultrarapid cycling was investigated during 8 consecutive days of ultrarapid cycling and 4 weeks later, after remission under treatment with valproate. The handwriting skills of the patient followed the same rhythmic changes of the psychopathology in the first part of the study and a steady pattern in the second phase, after remission. Therefore, it can be assumed that the handwriting skills reflect a state marker of the disease. Poorer handwriting skills on the manic days, as compared to the depressive ones, support the hypothesis of a low arousal in manic patients. Copyright (C) 2000 S. Karger AG, Basel

Platelet monoamine oxidase activity in alcoholics with and without a family history of alcoholism

A number of studies point at platelet monoamine oxidase (MAO) activity being reduced in alcoholics with a family history of drinking, this being a possible vulnerability marker for alcoholism. To test this hypothesis, we examined a group of recently detoxified alcoholics with high (n = 25) and low genetic loading for alcoholism (n = 28) and a group of healthy controls (n = 21). Clinical assessments were made using the SCID II interview for psychiatric disorders, the Family History Assessment Module and the Semi-Structural Assessment of Genetics in Alcoholism, a questionnaire especially designed for genetic studies. Platelet MAO activity with and without ethanol stimulation and the percentage of MAO activity with ethanol did not differ between groups. The only significant difference was a lower inhibition of MAO activity with ethanol in alcoholics both with and without a family history compared to controls. In patients with antisocial personality traits, platelet MAO activity was also not found to be different from other alcoholics. Our findings question the hypothesis of reduced platelet MAO activity to be a possible vulnerability marker for alcoholism. Copyright (C) 2000 S. Karger AG. Basel