Abstract: We investigated the spontaneous brain electric activity of 13 skeptics and 16 believers in paranormal phenomena; they were university students assessed with a self-report scale about paranormal beliefs. 33-channel EEG recordings during no-task resting were processed as sequences of momentary potential distribution maps. Based on the maps at peak times of Global Field Power, the sequences were parsed into segments of quasi-stable potential distribution, the 'microstates'. The microstates were clustered into four classes of map topographies (A-D). Analysis of the microstate parameters time coverage, occurrence frequency and duration as well as the temporal sequence (syntax) of the microstate classes revealed significant differences: Believers had a higher coverage and occurrence of class B, tended to decreased coverage and occurrence of class C, and showed a predominant sequence of microstate concatenations from A to C to B to A that was reversed in skeptics (A to B to C to A). Microstates of different topographies, putative "atoms of thought", are hypothesized to represent different types of information processing.The study demonstrates that personality differences can be detected in resting EEG microstate parameters and microstate syntax. Microstate analysis yielded no conclusive evidence for the hypothesized relation between paranormal belief and schizophrenia.
Abstract: In this study, the spontaneous brain electric activity (multichannel EEG) of 16 believers
in paranormal phenomena and 13 skeptics was compared. The participants were selected
from volunteer university students through a self-report scale for paranormal beliefs and
experiences. Since paranormal belief has been associated with schizotypy which in turn has
been claimed to correlate with an increased risk to develop schizophrenic episodes, the
present results were compared with previous schizophrenia studies.
Multichannel electroencephalographic (EEG) data was collected during no-task resting
with closed eyes. Two main analysis approaches were used: (1) EEG microstate analysis and
(2) brain functional tomography (low resolution electromagnetic tomography LORETA).
(1) Microstate analysis views EEG potential tracings as sequences of momentary
potential distribution maps (‘landscapes’). These sequences are parsed into temporal
segments of quasi-stable landscape, the microstates, putative ‘atoms of thought’ of about 100
ms duration. The microstates were clustered into four classes (A-D) that are considered to
represent different types of information processing. Believers compared to skeptics showed a
significantly higher time coverage and occurrence frequency of microstate class B. Analysis of
the temporal sequence (syntax) of the microstate classes revealed that believers showed a
predominant sequence of microstate concatenations from A to C to B to A that was reversed
in skeptics (A to B to C to A).(2) LORETA is an ‘inverse solution’ method that determines the 3-dimensional
intracerebral distribution of the electric neuronal generators based on head surface EEG
measurements. Across subjects and for each of the 8 independent EEG frequency bands,
strength of activity in the 6239 ‘eLORETA’ voxels in cortical areas was correlated with
the belief scores obtained from the questionnaire. Significances of correlations were corrected
for multiple testing using a permutation procedure. Only activity of the 8.5–10 Hz EEG
frequency band correlated at corrected P < 0.10; the extreme correlation was r = .566
(uncorrected P < 0.001, corrected P = 0.054) in the right posterior part of the insular cortex
(Brodmann area 13).
Both approaches successfully detected differences in brain electric mechanisms of the
two groups that displayed belief in or rejection of the paranormal. In a no-task situation, the
two groups differ in their sequencing of the building blocks of thought, and in the tomographic patterns of brain activity. On the other hand, the present results that were
obtained from believers with the two analysis approaches clearly did not agree with previous
findings in schizophrenic patients. In conclusion, the results did not show direct evidence for
putative similarities of brain electric mechanisms between believers and schizophrenics.
Abstract: The tyrosine hydroxylase (TH; EC 1.14.16.2) is a rate-limiting enzyme in the dopamine synthesis and important for the central dopaminergic system, which controls voluntary movements and reward-dependent behaviors. Here, to further explore the regulatory mechanism of dopamine levels by TH in adult mouse brains, we employed a genetic method to inactivate the Th gene in the nigrostriatal projection using the Cre-loxP system. Stereotaxic injection of adeno-associated virus expressing Cre recombinase (AAV-Cre) into the substantia nigra pars compacta (SNc), where dopaminergic cell bodies locate, specifically inactivated the Th gene. Whereas the number of TH-expressing cells decreased to less than 40% in the SNc 2 weeks after the AAV-Cre injection, the striatal TH protein level decreased to 75%, 50%, and 39% at 2, 4, and 8 weeks, respectively, after the injection. Thus, unexpectedly, the reduction of TH protein in the striatum, where SNc dopaminergic axons innervate densely, was slower than in the SNc. Moreover, despite the essential requirement of TH for dopamine synthesis, the striatal dopamine contents were only moderately decreased, to 70% even 8 weeks after AAV-Cre injection. Concurrently, in vivo synthesis activity of l-dihydroxyphenylalanine, the dopamine precursor, per TH protein level was augmented, suggesting up-regulation of dopamine synthesis activity in the intact nigrostriatal axons. Collectively, our conditional Th gene targeting method demonstrates two regulatory mechanisms of TH in axon terminals for dopamine homeostasis in vivo: local regulation of TH protein amount independent of soma and trans-axonal regulation of apparent L-dihydroxyphenylalanine synthesis activity per TH protein.
Abstract: A sensitized dopamine system may be linked to the genesis of psychotic symptoms in schizophrenia. Following withdrawal from amphetamine exposures, psychotic-like traits have been robustly demonstrated, but the presence of cognitive/mnemonic deficits remains uncertain.
Abstract: Introduction: We studied the subjective intensity of headache
as reflected by EEG spectral power and by activated brain
regions (functional imaging).
Methods: In 16 migraine patients without aura (6 medicated;
mean age 38 ± 7.7 years; 12 women), 19-channel EEG was
recorded during initial resting (4 min) on an attack-free day;
65.6 s artifact-free EEG was available on average per patient.
Patients self-rated (visual-analog) headache intensity. For
each of the eight independent EEG frequency bands, mean of
spectral power (absolute and relative) across channels, and
LORETA functional images (absolute and relative voxel strength)
were computed. These values were correlated with subjective
headache intensity.
Results: Correlations were negative (p <0.1) with absolute
power in the delta, alpha2, beta1 and 3, and gamma bands, but
positive (p <0.1) with relative power in delta and beta2. Absolute
LORETA voxel strength (corrected for multiple testing p <0.1)
correlated negatively in all bands except delta; relative voxel
strength correlated positively with delta through alpha1. Negative
correlations with absolute LORETA voxel strength concerned
only left anterior voxels in theta and alpha1, only left-hemispheric
in beta1 and beta2, predominantly left in alpha1 and beta3,
but more right in gamma; all positive correlations with relative
strength were right anterior (delta, theta and alpha1). Medicated
and unmedicated patients showed comparable tendencies.
Conclusion: With increasing headache intensity, EEG absolute
power decreased, with left hemispheric localization (in some
frequency bands predominantly anterior), while relative power
increased exclusively right anterior. These results suggest that
increasing headache intensity is associated with increasing
predominant anterior left hemispheric activation (supported in
part by Bial Foundation Grant #44-06).
