Enhancement of stereotypy induced by nomifensine in rats during continuous chronic haloperidol treatment

Stereotyped behaviour induced by apomorphine (0.125 mg/kg s.c.) was inhibited in rats treated continuously for 20 months with haloperidol (1.4–1.6 mg/kg/day) while that induced by a higher dose of apomorphine (1.0 mg/kg s.c.) was enhanced. Stereotypy induced by nomifensine (3.125–25.0 mg/kg i.p.) was not inhibited at any dosage level in haloperidol-treated rats, and was enhanced by higher doses of nomifensine. The results indicate that the behavioural effects of endogenously released dopamine may not remain inhibited in rats undergoing chronic neuroleptic treatment.     

Effect of melatonin and pinealectomy on brain electrical activity of rats at different times of day

Department of Pharmacology, Stavropol' Medical Institute Laboratory of Psychopharmacology, Research Institute of Pharmacology, Russian Academy of Medical Sciences, Moscow (Presented by Academician of the Russian Academy of Medical Sciences G. N. Kryzhanovskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 114, No. 9, pp 286–288, September, 1992.     

Spectral analysis of spontaneous contractions of the isolated portal vein of rats

Summary The spontaneous contractions of segments of rat portal veins have been examined in vitro under isotonic and isometric conditions. The power density spectra of recorded time series lasting 10–60 min were calculated. The spectra usually consist of harmonic frequency components. Only during shorter periods of analysis (10 min time series) we sometimes found additional non-harmonic components. All frequency components are proportionally shifted by changes of the bath temperature according to an average Q₁₀ of 2.0. Increase of the load decreases the frequency of the contractions.The results of the spectral analysis, indicating a preponderance of a single source of periodicity, were supported by direct evidence of a pacemaker region. By recording contractions after systematic dissections of the portal vein segment, we found that spontaneous activity is generated at the central end of the segment.This work was supported by the Austrian Research Fund     

Spectral analysis of EEG responses

The techniques used and the results obtained in a spectral analysis of two specific responses in the human electroencephalogram are presented in this paper. The purposes are to show how the techniques may be applied to the necessarily short lengths of EEG data and to illustrate these techniques and the useful results obtained by relevant examples. The necessary data-processing procedures and precautions for transforming from the time to frequency domain are presented in a tutorial fashion. The importance of augmenting zeros, choice of the most appropriate data window and pretransformation of the data to avoid the combined effects of energy loss and low frequency content biasing caused by windowing is explained. The pros and cons of the tapered-cosine (Tukey) and Kaiser-Bessel windows are illustrated. The usefulness of applying certain statistical tests, which are based on a physical model of the responses, to the harmonic components of the responses is demonstrated. Thus a comparison is made between the features of auditory evoked responses and of the contingent negative variation, and the usefulness of predictive statistical diagnosis in differentiating between subject groups is illustrated by application to normal subjects and Huntington's chorea patients.     

NMDA component in the effects of piracetam and new nootropic peptide GVS-111 on the neocortical and hippocampal EEG in conscious rats

The effects of new nootropic dipeptide GVS-111 (N-phenylacetyl-L-prolylglycine ethyl ester) on EEG spectral characteristics were compared with those of piracetam. The EEG was recorded in the cortex and hippocampus of nonanesthetized nonrestrained rats with chronically implanted electrodes. GVS-111 and piracetam induced similar changes in EEG spectral profile in both structures increasing the α-band power and decreasing the power of the β-and δ-bands. These effects were prevented by intracerebral injection of 10⁻¹⁰ mol NMDA receptor antagonist (±)-3-(2-carboxypiperazine-4-il)-propyl-l-phosphonic acid. The data correlate with behavioral and neurochemical findings and suggest that NMDA receptors can be specifically involved in the mechanisms of nootropic effects of piracetam and GVS-111. Translated fromByullenten' Eksperimental'noi Biologii i Meditsiny, Vol. 128, No. 8, pp. 190–193, August, 1999     

麻醉剂浓度对大鼠暴发-抑制脑电特征的影响

暴发-抑制脑电图(EEG)是深度麻醉状态下EEG活动受到严重抑制的表现。为定量研究暴发-抑制波形特征与麻醉剂浓度之间的关系,本文采用暴发-抑制比、暴发频率、暴发幅度和抑制幅度4个时域指标,分析大鼠麻醉模型在不同异氟烷浓度下的EEG特征。结果表明,暴发-抑制脑电的4个指标均随异氟烷浓度的改变而变化:异氟烷浓度越大,暴发-抑制比和暴发幅度越大,暴发频率和抑制幅度越小。暴发-抑制比可快速反映异氟烷浓度的变化,且个体间一致性高,有潜力作为深度麻醉状态下暴发-抑制EEG较理想的特征指标。     

Spectral analysis of the fetal electrocardiogram

The spectral curves of the averaged fetal and maternal electrocardiograms as recorded from the abdomen were studied. The power spectrums were obtained using a technique which includes the subtraction of an averaged maternal ECG waveform using cross-correlation function and fast Fourier transform algorithm. The spectral curves of the averaged maternal and fetal ECG waveforms obtained from 21 pregnant women who had gestation periods of 32–41 weeks were studied. It was found that the poor signal to noise ratio, the high rate of coincidence between maternal and fetal ECGs and the similar frequency spectra of the signal and the noise components make an analysis of the abdominal ECG using conventional filtering technique rarely possible and an alternative method should be used.     

Electroencephalogram spectral analysis by the direct and indirect methods: a comparison

An artificially-created electroencephalogram was used to perform a comparison between the indirect and direct analysis methods. The results obtained by Fourier transform of the correlation function and smoothing of Fourier series development differ for a stochastic process in which the correlation functions are not sufficiently damped. Some mathematical framework is also appended in which the difference is worked out from a more theoretical point of view. In order to obtain results independent of inherent conditions, which in the simplest way can be detected by calculating the correlation functions, the indirect method is preferable.     

Effect of psychostimulants on rats relearning the direction of avoidance in a U-shaped maze

The ability of rats to relearn the direction of the avoidance response was studied in a U-shaped maze. Four training series of experiments were carried out, each with a different direction (to right or left) of running. In small and average doses (0.5 and 2 mg/kg) amphetamine shortened the latent periods of the responses and had no effect on the animals ability to relearn. A large dose of amphetamine (5 mg/kg) shortened the latent period of response but, at the same time, impaired relearning of the direction of the avoidance response, and this correlated with the strengthening of spatial preference. Caffeine, in doses of 25 and 50 mg/kg, did not affect the rats' ability to relearn.Department of Pharmacology, Medical Institute, Chita. (Presented by Academician of the Academy of Medical Sciences of the USSR V. V. Zakusov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 81, No. 5, pp. 554–556, May, 1976.     

Different EEG topographic effects of painful and non-painful intramuscular stimulation in man

To clarify the specific effects of muscle pain on electroencephalogram (EEG) activation in man, painful and non-painful sensations were produced by intramuscular injections of capsaicin and vehicle solution in the left brachioradialis muscle, with identical procedures in 15 male volunteers. Thirty-one channel EEG data acquired before, during and after the two injections were analysed and compared in respect of topography and power spectrum. Although the painful and non-painful muscular stimulations evoked similar EEG topographic patterns, statistics demonstrated that distinct EEG activation over different areas of the head were induced by the painful and non-painful stimulation compared with the baselines. The decreases in theta and alpha-1 (8-10.5 Hz) activity in central and posterior parietal parts were evoked by non-painful stimulation, but the decreases in alpha-1 and alpha-2 (11-13.5 Hz) activities in the posterior part of the head were induced by painful stimulation. The alpha-2 activity augmented during the waning pain following a decrease in the overt pain. Comparing the EEG changes between baseline, non-painful and painful stimulations as well as waning pain, we found that the increase in beta-2 activity during muscle pain was significant over the extensive areas of the head, whereas a significant increase in alpha-2 activity took place at the posterior part of the head during waning pain following a marked decrease in overt pain. These results may imply that the painful and non-painful muscular stimulations evoke distinct EEG activation in different neural networks of the human brain and the intensity of nociceptive input from muscle may encode the variety of topographic EEG changes.     

Spectral analysis of hippocampal slow wave activity during feeding and drinking in the rabbit

The dorsal hippocampal electrical activity was recorded in rabbits and correlated with discrete components of consummatory responses during drinking and eating, as well as during immobile attention. Power-spectral and autocorrelation analyses revealed that chewing was accompanied by two dominant frequencies, one of low power from 0.5 to 3.0 Hz, and one in the theta range of relatively low power and frequency. Theta rhythms accompanied all other components of ingestive behavior, with an increasing order of frequencies from licking of water, eating of liquid food, biting of solid foods, to immobile attention, whereas power of theta remained invariant across these conditions.     

Spectral analysis of event-related EEG responses during short-term memory performance

Summary Averaged event-related EEG frequency response profiles were generated from normalized spectral analysis data obtained in 2 studies of short-term memory. A continuous performance task was used requiring a keyboard response to targeted letter sequences presented on a video screen at 2 sec. intervals. Seven 2 Hz frequency bands between 5–15 Hz were evaluated. In the first study (n=14) response profiles from control and target stimuli were compared. This analysis disclosed 1) a short latency increase at 5–7 and 7–9 Hz in posterior cortex that was identical in both conditions and was attributed to frequency manifestations of the extrinsic visual evoked response (VEP), 2) a separate long-latency increase of uncertain origin at 5–7 Hz in anterior cortex only in the task condition, and 3) a generalized mid-latency alpha frequency suppression and recovery pattern (event-related desynchronization, or ERD) in all bands during both conditions. The ERD in bands between 9–13 Hz was significantly increased at left central and bilateral parietal cortex during target recall. The second study (n=26) compared good vs. poor performance in the target recall task. Findings disclosed significant differences at 7–9 Hz localized to posterior temporal cortex bilaterally. These differences included reduced magnitude in the VEP component and increased suppression in the ERD component among good performers.This work was supported by the Veterans Administration, the Northrop-Grumman Corporation, and the United States Air Force.     

Spectral analysis of courtship songs in behavioral mutants ofDrosophila melanogaster

Spectral analyses were applied to the courtship songs of the mutantscacophony (cac), dissonance (diss), fruitless (fru), andperiod (per), as well as to the double mutantcac diss. Aberrant intervals between song pulses were observed indiss, cac, cac diss, andfru songs,diss males displayed a defect in song hums manifested by an irregular sine wave, although the fundamental frequencies were normal. Sine song frequencies and intrapulse frequencies were aberrant incac diss males. Two per mutant alleles (per ^o1 andper ^s) were associated with normal seng pulses and hums. These findings are discussed with regard to the mechanisms of song production and the role of these sounds inDrosophila reproduction.This research was supported by US NIH Grant GM-21473 and NIH Training Grant NS-07292.     

Phenomenological Description of Local Extremes on Contrast Sensitivity Curves

Previous studies have demonstrated that human contrast sensitivity curves have marked extremes [4]. This phenomenon has not yet been investigated. The present report describes studies of plots of frequency-contrast characteristics obtained using gratings with orientations of 0°, 90°, and 135°. The results showed that: 1) periodically located extremes were marked on the averaged curve obtained using gratings with an orientation of 0°, while use of gratings with orientations of 90° and 135° gave weak peaks; 2) on repeat testing, the amplitudes of extremes decreased sharply, to the level of disappearance by day 5 of testing. These data lead to the suggestion that the phenomenon of local extremes is not associated with random errors by the subjects but reflects the specific characteristics of information processing by the visual system. Translated from Rossiiskii Fiziologicheskii Zhurnal imeni I. M. Sechenova, Vol. 94, No. 5, pp. 566–573, May, 2008.