|
|
| 11. |
Nicotine Affects the Occipital Theta Rhythm after Lesion of the Pedunculopontine Tegmental Nucleus in Rats |
| |
Neuropsychobiology,
Volume 35,
Issue 2,
1997,
Page 102-107
Andreas Bringmann,
Preview
|
PDF (1164KB)
|
|
摘要:
The pedunculopontine tegmental nucleus (PPTg) is assumed to be one of the brainstem sites for eliciting the theta rhythm that is expressed in rat hippocampal and occipital EEG in high arousal states. Unilateral lesions of the PPTg in rats induced a hemispheric asymmetry in the expression of occipital theta waves during exploratory sniffing with a significantly lower mean power in the lesioned hemisphere. Acetylcholine was found to be the main neuro-transmitter used by the PPTg neurones. Therefore, the present study was conducted to determine if nicotine was effective in counteracting the lesion-induced hemispheric asymmetry of the theta waves in the occipital EEG of freely moving rats. In 12 rats the PPTg was unilaterally lesioned by ibotenic acid. The occipital EEG was recorded from both hemispheres in three waking states and after intraperitoneal nicotine and physostigmine application. Nicotine reversed the lesion-induced hemispheric asymmetry of the theta rhythm during exploratory sniffing in a dose-dependent manner. Physostigmine did not reverse the hemispheric asymmetry of the theta waves. The present study indicates that a nicotinic component may be involved in the reinforcement or elicitation of the theta rhythm by the pontomesencephalic tegmentum.
ISSN:0302-282X
DOI:10.1159/000119399
出版商:S. Karger AG
年代:1997
数据来源: Karger
|
| 12. |
Spectral Analysis of P300 Generation in Depression and Schizophrenia |
| |
Neuropsychobiology,
Volume 35,
Issue 2,
1997,
Page 108-114
Joachim Röschke,
Jürgen Fell,
Preview
|
PDF (1362KB)
|
|
摘要:
In the past it was reported in several studies that both depressive and schizophrenic patients exhibit reduced P300 amplitudes compared to healthy controls. In order to elucidate the underlying mechanisms of spectral P300 generation, we analysed P300 responses in depression and schizophrenia by a frequency based approach. Herefore, the amplification (poststimulus/prestimulus) of spectral power in different frequency bands was evaluated for non-target and target epochs. Generally, we found that P300 responses are accompanied by a pronounced frequency amplification in the delta and theta range. For the depressive patients we detected only under target condition a statistically significant reduction of alpha and gamma amplification compared to controls. In contrast to this, we observed a highly significant reduction of delta amplification in schizophrenic patients, under both target and non-target conditions.
ISSN:0302-282X
DOI:10.1159/000119400
出版商:S. Karger AG
年代:1997
数据来源: Karger
|
|
首页
