Search

The serotonin transporter (5-HTT) plays a key role in regulating serotonergic transmission via removal of serotonin (5-hydroxytryptamine, 5-HT) from synaptic clefts. Alterations in 5-HTT expression and 5-HT transmission have been shown to cause changes to adult behavior including fear. The objective of the present study was to investigate the 5-HTT role in fear in birds at the very early stages of post-hatching life. Using an avoidance test with an elevated balance beam, which was based on depth perception and the respective fear of heights, we assessed fear-related avoidance behaviors of newly hatched chicks of the three functional 5-HTT genotypes W/W, W/D and D/D. Newly hatched chicks of the genotype D/D, which was linked to high 5-HTT expression, showed less intensive avoidance responses as measured by decreased latency to jump than W/W and W/D chicks. Further, significantly fewer D/D hens than W/W hens showed fear-like behavior that resembled a freezing response. Furthermore, in an arousal test the arousal reaction of the chicks in response to an acute short-term visual social deprivation in the home compartment was assessed 5 weeks after hatching, which also revealed that D/D chicks exhibited decreased arousal reaction, compared to W/W chicks. Thus, the results indicate that fear responses differ in D/D chicks in the early post-hatching periods, possibly due to the different expression of 5-HTT respectively 5-HT levels in this strain.

Schlafbezogene Atemstörungen und insbesondere obstruktive Schlafapnoen stellen einen eigenständigen Risikofaktor für die Entwicklung einer arteriellen Hypertonie dar. Inwiefern die einzelnen Störungen und damit assoziierte Ereignisse, wie Entsättigungen, Arousals oder Schnarchen zu kurzfristigen Blutdruckschwankungen führen, war in der Literatur bisher nur in deutlich geringerem Ausmaß untersucht worden. Um das zu ergänzen wurde untersucht, ob es eine feste zeitliche Abfolge von einem auslösenden Ereignis bis zu einer Blutdruckveränderung gibt, ob diese Sequenz nach jedem gleichnamigen Ereignis einem festen Schema folgt, ob der Ereignisbeginn oder dessen Ende als auslösender Anteil einer Blutdruckreaktion anzusehen ist und ob es sich um einen Anstieg oder Abfall handelt. Hierfür wurde bei Probanden mit schlafbezogenen Atemstörungen eine der Routine folgende Polysomnographie abgeleitet und außerdem wurden mittels „beat-to-beat“-Blutdruckmessung von Portapres deren nächtliche Blutdruckveränderungen aufgezeichnet. Zur Auswertung der gewonnenen Blutdrucksignale wurde anschließend erstmals die Methode der Mittelung ereignisbezogener Datenepochen verwendet, die der Methode der „event-related brain potentials“ ähnlich ist und dem Zweck dient, aus mehreren ereignisassoziierten Blutdruckreaktionen wiederkehrende Anteile darzustellen und singulär auftretende, zufällige Veränderungen aus dem Signal herauszufiltern. Die Anwendung der Methode erwies sich in der vorliegenden Arbeit als probates Mittel für die Aufreinigung von Blutdrucksignalen. Es konnte gezeigt werden, dass bei allen respiratorischen Ereignissen und Arousals der gesamten Probandengruppe, sowohl bezogen auf den Beginn, als auch auf das Ende, reproduzierbare Veränderungen der Blutdruckkurve festzustellen sind. Es stellte sich heraus, dass diese Veränderungen, unabhängig von dem damit assoziierten Ereignis, einen hohen Grad morphologischer Analogie teilen und jedes Mal nicht nur ein Anstieg, sondern auch ein Abfall des Blutdruckes verzeichnet werden konnte. Es ließ sich ein festes Schema abbilden: Mit dem Ereignisbeginn aller schlafbezogenen Atemstörungen (SBAS) kommt es zunächst zu einem deutlichen Blutdruckabfall, der von einem mit dem Ereignisende in Verbindung stehenden Blutdruckanstieg abgelöst wird. Im Zusammenhang mit Arousals lässt sich ein gegensätzliches Blutdruckverhalten erkennen. Deren Beginn folgt ein Blutdruckanstieg und deren Ende steht in Assoziation mit einem Blutdruckabfall. Diese Blutdruckveränderungen folgten nicht unmittelbar auf schlafbezogene Ereignisse, sondern konnten erst nach einer gewissen Latenzzeit beobachtet werden. Als Ausnahme stellen sich Entsättigungen und Arousals heraus, die in direktem Zusammenhang mit einer unmittelbar beginnenden Blutdruckreaktion stehen.

This review article addresses current knowledge on the arousal reaction during sleep. Diagnostic criteria of the arousal scoring in young children are provided. The possible protective role of the arousal reaction is discussed, and certain abnormalities of the arousal mechanisms in some patients with different types of sleep apneas are considered. Potential links between an abnormal arousal reaction and the origin of the sudden infant death syndrome are discussed.

症例は38歳の女性で, 統合失調症に対し複数の治療薬を内服していた. 乳房切断術後2日目に術後出血に対する止血術を受けた. プロポフォールを用いた全静脈麻酔管理中, 出血点確認の昇圧目的でエチレフリンを8分間に計7mg投与したところ, 強い体動と開眼がみられた. エチレフリンのβ作用による心拍出量の増加は, 肝腎血流増加による代謝クリアランスの増加によりプロポフォールの血中濃度を一過性に低下させ, 覚醒徴候の主な原因になったと考えられた. また, 統合失調症患者では血液脳関門の機能異常のため, 通常中枢神経に作用しない薬剤が作用する傾向がある. したがって, α作用を有するエチレフリンが覚醒に関与する中枢神経のα1受容体に働き, プロポフォールの血中濃度低下による覚醒徴候を助長した可能性が推察された.

This commentary is referred to the review signed by Rattemborg [N.C. Rattenborg, Evolution of slow wave sleep and palliopallial connectivity in mammals and birds. A hypothesis. Brain Res. Bull. 69 (2006) 20-29]. We propose that the review missed important aspects in relation to the characteristics of sleep in poikilotherm vertebrates and in the evolution of sleep. Poikilotherms continuously show an EEG dominated by slow waves, but its highest amplitude appears not during sleep, but during active waking. In addition, they show an arousal reaction which consists in an increase in EEG amplitude and synchrony, opposite to mammals and birds. As a consequence, most of the conclusions proposed in the review should be rejected.

We investigated the correlation between electroencephalography (EEG) abnormalities and dementia in Parkinson’s disease. Three groups of subjects were examined: Parkinson’s disease patients without dementia, Parkinson’s disease patients with dementia, and healthy age-matched controls. Dementia was assessed with the use of Mini-Mental State Examination. All subjects underwent a routine EEG examination with determination of arousal reaction to eye opening, hyperventilation and photic stimulation. Demented patients with Parkinson’s disease more often showed no response to eye opening and presented more slow wave activity in comparison to non-demented patients and healthy controls.

Different anesthetic drugs can produce different electroencephalographic (EEG) patterns. Nondrug induced influences, such as surgical stimulation, may also alter the EEG in anesthetized patients. Increases of delta activity are interpreted as signs of deepening of anesthesia. These EEG patterns are sometimes also found in frontal leads after surgical stimulation during isoflurane anesthesia. However, to avoid incorrect anesthetic management under EEG monitoring, this phenomenon of "paradoxical arousal" must be taken into consideration. This study demonstrates that, after surgical stimulation, frontal activity was enhanced in the 2-3 Hz and 3-4 Hz frequency bands. On the other hand, in the subdelta range (the 0.05-1 Hz and 1-2 Hz frequency bands), there was an opposite reaction. This significant (p

Изучено влияние функциональных нагрузок на показатели электроэнцефалограммы у практически здоровых и с разными формами нарушений испытуемых. Установлено, что у последних значительно снижена реакция на функциональные пробы. Нарушения биоэлектрической активности головного мозга, вызванные сосудистыми патологиями, а также заболеваниями, обусловленными черепно-мозговыми травмами и хронической дисциркуляторной энцефалопатией, выявляют пробы активации и гипервентиляции. Проба фотостимуляции позволяет оценить функциональные изменения биоэлектрической активности головного мозга, вызванные алкогольной интоксикацией организма., The article covers the influence of functional loads on electroencephalography readings in healthy people and patients with various disorders. It was established that patients with various disorders have a significantly lower response to functional tests. The malfunctions of brain bioelectricity caused by vascular pathologies and diseases caused by head injuries and chronic cerebropathy are revealed by activation and hyperventilation tests. The photostimulation test makes it possible to estimate the functional changes in brain bioelectricity generated by alcohol intoxication.

AIMS: Waking up in response to an alarm-clock may evoke a stress reaction that leads to rising glucose concentrations. METHOD: 30 type 1-diabetic patients participated in 3 overnight conditions: (a) with an alarm-clock set at 2 h intervals for glucose self monitoring, (b) with a nurse performing blood glucose determinations, and (c) with the patients left undisturbed. Continuous glucose monitoring (CGM) was performed with a GlucoDay ® S device. RESULTS: After waking up in response to an alarm-clock, CGM-determined glucose concentrations rose by 18±6 mg/dl at 4 a.m. (p=0.0003), whereas negligible increments were seen with nurse assistance (e. g., 0±4 mg/dl at 4 a.m.). CONCLUSIONS: Waking up in response to an alarm-clock leads to an arousal reaction that causes significant elevations in glucose concentrations. Continuous glucose monitoring is a suitable method to detect such short-lived increments in glucose concentrations. But at the moment the CGMS is not able to substitute for inpatient glucose profiles. Registered with ClinicalTrials.gov, Identification number NCT00740012.

Hintergrund und Ziele: In dieser Studie sollten mögliche zentralnervöse Nikotineffekte, ausgelöst durch sensorische Reizung (trigeminal und olfaktorisch), und deren zeitlicher Verlauf von den systemischen, pharmakologischen Nikotineffekten differenziert werden. Da die sensorische Komponente eine wichtige Rolle bei der Anwendung von Nikotinersatzstoffen einnimmt, sollte der Versuchsaufbau dazu dienen, neben subjektiven auch objektive Parameter für die Testung von Nikotinersatzstoffen zu etablieren. Methoden: In einem einfach verblindeten, 3-fach-crossover-Design wurden zehn freiwillige gesunde Teilnehmer an vier Versuchstagen randomisiert untersucht. Der Studienplan wurde von der lokalen Ethik-Kommission positiv begutachtet. Als objektive Parameter wurden die Powerspektren aus dem Hintergrund-EEG und die Amplituden bzw. Latenzzeiten der visuell evozierten Potentiale (VEP) erfasst. Blutentnahmen zur Bestimmung der Nikotin-Konzentration im Serum wurden zu drei festgelegten Zeitpunkten durchgeführt. Während der drei Sitzungen eines Messtages wurde mit Hilfe eines Olfaktometers die Pharynxhinterwand des jeweiligen Probanden mit drei unterschiedlich starken Nikotinreizen stimuliert. Die jeweilige Reizstärke wurde in einer Probesitzung individuell für jeden Versuchsteilnehmer bestimmt, um eine leichte, mittlere und deutlich überschwellige trigeminale Stimulation zu erreichen. In einer Vergleichsuntersuchung, die nicht Schwerpunkt dieser Arbeit sein soll, wurden die Messungen unter dem Einfluss von randomisiert dargebotenen Zigaretten (Nikotingehalt: 0,08mg, 0,51mg, 1,01mg) wiederholt durchgeführt. Die resultierenden EEG-Daten wurden im Hinblick auf Veränderungen der Amplituden bzw. Latenzzeiten der VEP-Signale (P0, N1, P1, N2, P2) und bezüglich Verschiebungen bei den Powerspektren (Frequenzbänder: Sub- Delta, Delta, Theta, Alpha 1, Alpha 2, Beta 1, Beta 2) verblindet ausgewertet. Am Ende jeder Messung wurden die jeweils applizierte Reizstärke und das momentane, mittels visueller Analogskalen und anhand eines Fragebogens zur Hedonik, von den Probanden bewertet. Ergebnisse: Die Auswertung der subjektiven Parameter zeigte, dass die Teilnehmer dem stärksten Nikotin-Reiz die stärkste Intensität, die stärkste Empfindung in Mund-Rachenraum und den deutlichsten pelzige Beigeschmack zuordnen konnten. Auch in der Vergleichsuntersuchung wurde nach inhalativer Applikation des Nikotins eine signifikante Dosisabhängigkeit für die subjektiven Parameter „Empfindung“ und „Zufriedenheit“ gefunden. Unter olfaktometrischer Stimulation mit der stärksten Prüfkonzentration, zeigten die VEPs im Anschluss an die zweite Stimulation eine signifikante Zunahmen der Amplitude N1P1 an O2, sowie signifikante Zunahmen der AUC P1N2 an den Ableitepositionen O1 und OZ. Diese Effekte waren jedoch regredient im weiteren Untersuchungsverlauf. Unter Nikotin-Inhalation kam es zu einer Zunahme der P1-, P0N1-, N1P1- und N2P2-Amplituden, sowie zu einer Verkürzung der Latenzzeiten der P1- und der P2-Signalkomponenten. In den Powerspektren konnte ebenfalls unter olfaktometrischer Applikation eine signifikante Zunahme der 2-Power über die gesamte Untersuchungszeit, unabhängig von der Prüfkonzentration, nachgewiesen werden. Diskussion: In der Vergleichsuntersuchung, bei Inhalation von Nikotin, konnte die pharmakologische Wirkung auf das zentrale Nervensystem elektrophysiologisch erfasst werden. Das Arousal ging konform mit den subjektiven Einschätzungen der Probanden und den gemessenen Serum-Nikotin-Konzentrationen. In der vorliegenden Arbeit wurde nach sensorischer Reizung des Rachens eine Amplitudenzunahme der VEPs unmittelbar im Anschluss an die ersten Nikotinapplikationen gefunden. Diese kann als frühe, sensorische Komponente bei der Nikotinwahrnehmung angesehen werden. Die Hypothese, dass es sich um einen rein sensorischen Effekt handelt, wird durch die im Serum gefundenen, niedrigen und sich im Rahmen der Stimulation kaum ändernden Nikotin-Konzentrationen gestützt. Dieser Effekt war im Verlauf der Messungen durch Adaptation und Ermüdung geringer ausgeprägt. Auch die Ergebnisse der Powerspektren lassen ein sensorisch induziertes Arousal erkennen, das sich zudem dosisunabhängig darstellte. Insgesamt kann festgehalten werden, dass rein sensorische Effekte zeitlich meist an frühe Phasen der Stimulation gebunden sind und dass sich diese mit der getesteten Methode erfassen lassen. Introduction and aim: In this study possible sensory effects (trigeminal and olfactory) induced by nicotine on the central nervous system and their temporal changes should be seperated from systemic, pharmacological effects. The better understanding of nicotine effects on the sensory system might help to establish objective parameters for testing nicotine replacement drugs. Methods: Ten healthy subjects were included in a single-blinded,randomized, 3-way-crossover study repeated on four days. The protocol was approved by the local ethics committee. Power spectra from continuous recorded EEG as well as amplitudes and latencies from visual evoked potentials (VEP) served as objective parameters. Blood samples were taken at three predefined time points during measurements to obtain nicotine serum concentrations. During the three sessions of one experimental day, three individually adjusted nicotine concentrations were delivered by an olfactometer to the pharyngeal mucosa. The individual concentrations were obtained for each subject in a training session prior to the experiments. In a comparative investigation, which is not the main focus of this thesis, measurements were repeated during smoking three different types of cigarettes (nicotine contents: 0.08mg, 0.51mg, 1.01mg). Changes in power spectra (subdelta-, delta-, theta-, alpha 1-, alpha 2, beta 1- and beta 2-activity) as well as changes from baseline regarding amplitudes and latencies of the VEPs (P0, N1, P1, N2 and P2) were analyzed on a blinded condition. After each session, subjects were asked to estimate their actual condition and the nicotine stimulus by using visual analogue scales and a hedonic questionnaire. Results: The evaluation of the subjective data demonstrated that participant’s estimates correlated with the concentration of the applied nicotine stimuli in terms of stimulus intensity, sensation and cotton mouth sensation. Similar significant and dose dependent results were found for parameters such as “sensation” and ”satisfaction” in the comparative study after inhaling nicotine by cigarettes. During olfactometer stimulation with the highest nicotine concentration, the VEPs demonstrated after the second stimulus a significant increase in amplitudes N1P1 at O2 and a significant increase in AUC P1N2 at O1 und OZ. However, these effects decreased at later time points during measurements. During stimulation with inhaled nicotine an increase in amplitudes P1, P0N1, N1P1 und N2P2 as well as a decrease in latencies P1 and P2 could be detected. During olfactometer stimulation also a significant increase in the 2-power spectrum activity could be recorded during the entire observation period, regardless of the nicotine concentration used. Discussion: In the other part of the study using cigarettes for stimulation, the pharmacological effects in the central nervous system could be detected by means of electro-physiological recordings as expected. The recorded arousal correlated with subject’s estimates for stimulus intensity and also with nicotine concentrations found in the serum. In the actual study using pharyngeal stimulation to obtain sensory input only, the increase in VEP amplitudes after the first stimulus might be interpreted as an early sensory effect caused by nicotine. This hypothesis of an exclusive sensory effect is confirmed by the low nicotine concentrations found in blood samples. Additionally, the concentrations did not show any obvious change during stimulation. This effect on amplitudes was reduced at later time points of the measurement most likely due to adaptation and habituation. Furthermore, the results from the power spectra analysis revealed a sensory induced arousal which was independent of the nicotine concentration used. In conclusion it could be summarized, that the exclusive sensory effects are mainly linked to early parts of the stimulation period and that they are recordable with this experimental setup.

BACKGROUND: Disturbances of central regulatory processes of sleep and arousal are potential causes of nocturnal enuresis. The intranasal application of an ADH analogue is an established therapeutic option to influence nocturnal enuresis. The aim of the study was to evaluate effects of an ADH analogue on sleep and arousal in patients suffering from primary nocturnal enuresis. PATIENTS AND METHODS: In our study the influence of ADH analogue on sleep architecture was investigated by polysomnographic studies before and during therapy in 24 patients. RESULTS: In polysomnography arousal index and movement time were significantly improved after 6 weeks, sleep stages 1 to 4 did not change significantly. Treatment reduced the frequency of nocturnal wetting significantly and this effect lasted for another 6 weeks. CONCLUSION: The long lasting effect of ADH to reduce enuresis could possibly be caused by changes in arousal reaction and a normal wake up facilitation. HINTERGRUND: Veranderungen in der Entwicklung zentralnervos regulierender Prozesse werden als mogliche Ursachen bei der Enuresis nocturna diskutiert. Die intranasale Applikation von ADH-Analoga hat sich als therapeutische Moglichkeit etabiliert. In unserer Studie sollte der Einflus von einem ADH-Analogon (Desmopressin) auf die Schlafphasen und Aufwachreaktion (Arousal) bei Kindern mit Enuresis nocturna untersucht werden. PATIENTEN UND METHODE: Mit Hilfe der Polysomnographie wurden vor und wahrend der Therapie mit Desmopressin Veranderungen auf die Schlafarchitektur bei 24 Patienten mit En-uresis bewertet. ERGEBNISSE: Die Aufwachreaktionen sowie die Bewegungen wahrend des Schlafes zeigten einen signifikanten Anstieg nach 6 Wochen Therapie, die Schlafstadien 1 bis 4 veranderten sich aber nicht signifikant. Die nachtliche Enuresis konnte wahrend der Therapie signifikant reduziert werden und zeigte auch nach 6 Wochen Nachbeobachtung ohne Therapie keine erneute Zunahme der Enuresishaufigkeit. SCHLUSSFOLGERUNG: Die langanhaltende Reduktion der Enuresis auch nach Beendigung der ADH Therapie kann in der Normalisierung der registrierten Aufwachreaktionen wahrend des Schlafes begrundet sein.

A new system has been developed to assess human alertness and to alert the subject with acoustic stimulation in accordance with the assessed level of alertness. Dynamic characteristics of saccadic eye movement (saccade: SC) were used to calculate an alertness index. Digital signal processor was adopted for the calculation. The system was tested through eye tracking tasks. The results indicated that the developed system could awaken the subject by feeding sound back to the subject. Also, arousal reaction induced by the sound was visualized quantitatively by analyzing values of the alertness index after the stimulation. These results indicate applicability of the system not only to awakening device for accident prevention, but also to a tool for investigating effects of the stimulation.

The sleep-wake pattern of healthy preterm infants under two different schedules of routine procedures was studied by 4-day polygraphic-recording. Group-I experienced the usual routine care conditions, Group-II remained less disturbed by means of time-coordination of the procedures. Group-II-infants were less awake, showed a higher percentage of active sleep and the undisturbed phases of active and quiet sleep were longer than in Group-I-infants. Routine procedures left Group-II-infants more often in an unchanged state than Group-I-infants, the latter exhibiting an arousal reaction more frequently. The unknown effect of sleep disturbances in preterm-infants demands a reduction and coordination of routine procedures as far as possible.

Power-spectrum analysis of the electroencephalogram and inhaled-exhaled concentrations of halothane (when used), nitrous oxide, and carbon dioxide of 36 patients during surgical operations under general anesthesia were monitored. Electroencephalographic arousal reactions were detected in 24 patients and these were accompanied by irregular respirations in nine patients. Cardiac arrhythmias occurred following an arousal reaction in eight patients. The authors conclude that this electroencephalographic arousal phenomenon occurs frequently and deserves further investigation to define its clinical implications and how it might be avoided.

The effects of the arousal reaction on the reduction or habituation of nystagmus in the unanesthetized cat repeatedly rotated in darkness were determined. A reduction in nystagmus was associated with a reduction of alertness as indicated by the electroencephalogram, but alerting an animal by sounds occasioned only a temporary and partial recovery of nystagmus. Further, a continuous arousal sustained by cutaneous electric shock stimuli did not prevent habituation. It is concluded that a reduction of alertness is not wholly responsible for the nystagmic reduction and that other factors, not yet identified, play a powerful role.

On proprioceptive stimulation or after the intravenous administration of physostigmine rabbits show a very regular 4–7/sec activation within the rhinencephalon and diencephalon, while in cortical leads a simultaneous reduction of voltage occurs which is characteristic for the arousal reaction. The regular activity can be modified by electrical stimulation at a circumscript median area within the septum.

SUMMARY Following the audiogenic seizure in rats the mesencephalic and cortical postural reflexes as well as the conditioned alimentary reflexes were abolished. The duration of this postparoxysmal inhibition was dependent on the symptomatology of the seizure. It was lengthened by deafferentation of the olfactory or trigeminus nerve or by stimulation of the gastric interoceptors; no changes were found after optic deafferentation. During the inhibition the arousal reaction was elicited only by nociceptive stimulation. Later, after the audiogenic seizure, when conditioned reflexes were restored, it was possible to establish positive and negative alimentary conditioned reflexes. Respiratory frequency decreased after the seizure for about 20 minutes. During this period the respiratory centre was inexcitable by olfactory stimuli. The postparoxysmal inhibition after an audiogenic seizure as well as after an electro-shock has many symptoms in common with decerebrate rigidity. RESUME A la suite de la crise audiogenique chez les rats, les reflexes posturaux mesencephaliques et corticaux disparaissent, tout aussi bien que les reflexes alimentaires conditiones. La duree de cette inhibition postparoxysmal depend de la symptomatologie de la crise. Elle etait prolongee par la deafferentation des nerfs olfactif et trijumeau ou par la stimulation des interocepteurs gastriques; on n'a pas observe de changements apres la deafferentation optique. Pendant Finhibition, la reaction du reveil ne s'est produite que par suite d'une stimulation nociceptive. Plus tard, apres la crise audiogenique, quand se manifestent les reflexes conditiones, il est possible d'obtenir des reflexes conditiones alimentaires positifs et negatifs. La frequence respiratoire diminue 20 minutes a peu pres apres la crise. Pendant cette periode, le centre respiratoire n'est pas excitable par des stimuli olfactifs. L'inhibition postparoxysmale, qu'elle suive une crise audiogenique ou un electrochoc, comprend plusieurs symptomes de rigidite decerebree.

1. Bei pyknoleptischen Patienten wurde gepruft, ob die gelegentliche praparoxysmale Desynchronisierung des EEGs mit gesteigerter psychischer Aktivitat verknupft und damit als Ausdruck einer Weckreaktion aufzufassen ist. 2. Die Patienten musten verschiedene Signale fortlaufend beantworten. Die Antworten wurden synchron mit dem EEG registriert. Antwortzeit und Fehlerzahl wurden mit den Intervallwerten verglichen und statistisch ausgewertet. 3. Unmittelbar vor klinisch manifesten Absencen war die Antwortzeit signifikant verkurzt. 4. Unter 218 praparoxysmalen Antworten war keine falsch, wahrend im Intervall 2,4% der Antworten falsch waren. 5. Beide Feststellungen weisen auf eine kurze praparoxysmale Phase gesteigerter Aufmerksamkeit und Konzentration hin. Die gelegentliche praparoxysmale Desynchronisierung des EEGs mus daher als Zeichen einer arousal-reaction aufgefast werden. 6. Ferner fand sich eine statistisch gesicherte reziproke Beziehung zwischen praparoxysmaler Antwortzeit und Dauer des folgenden Anfalls, d. h. die Steigerung der Aufmerksamkeit ist deutlicher vor langerwahrenden, weniger auffallig vor kurzen und subklinischen Absencen. 7. Entstehung und Bedeutung der praparoxysmalen Weckreaktion und der damit verknupften Phanomene werden diskutiert. Die „praparoxysmale arousal-Phase“ ist wahrscheinlich ein obligatorisches Vorstadium des pyknoleptischen Anfalls. Die Dauer der folgenden Absence scheint in dieser Phase bereits festgelegt zu sein. Es wird auf die Moglichkeit hingewiesen, das wahrend dieses Vorstadiums auch erregungsbegrenzende Mechanismen ablaufen.

1. Brief inhalation of an anoxic mixture containing 7.5% O2 and 92.5% N2 causes a distinct arousal reaction appearing as a slow (4–7/sec) regular rhythm in the mesencephalic reticular formation, hippocampus, hypothalamus, nonspecific thalamic nuclei, parieto-occipital regions of the cortex, and desynchronization of electrical activity in the sensorimotor cortex. 2. For the structures studied, arousal reaction occurs first in the mesencephalic reticular formation and hippocampus. 3. The arousal reaction evoked by anoxia can persist after administration of chlorpromazine (5–8 mg/kg), which completely blocks nociceptive activation. 4. With higher doses of chlorpromazine (10–12 mg/kg) the arousal reaction evoked by anoxia is completely blocked.

Taurine, homotaurine, GABA and muscimol, given intraventricularly to the conscious, unrestrained rabbit cause hypothermia and a reduction in skeletal muscle tone. Taurine and homotaurine desynchronize areas of the motor and limbic cortices, while GABA and muscimol synchronize both tracings and markedly depress the arousal reaction following external stimuli.

In 1875 a young English physiologist, Caton, reported in the British Medical Journal that he had succeeded in recording weak electrical currents from the brain of rabbits and monkeys. Caton had found that a sudden potential change occurred when the animal turned its head or chewed some food. Even more fascinating was the observation that a potential change was induced when a flame, which was the only source of light available in the room, was placed in front of the animal’s eyes. Caton’s report passed unnoticed and remained unknown for many years, and several other authors later claimed priority for the discovery of ‘brain currents’. About 15 years after Caton’s discovery, a Polish physiologist, Beck, reported in Centralhlatt fur Physiologie that there were waxing and waning potential changes in the cortex and that these rhythmic potentials disappeared when the animal’s eyes were stimulated with light; this appears to be the first description of the arousal reaction.

A simple integrator to process the EEG of small laboratory animals is described. This device simultaneously integrates, at fixed short intervals, average wave frequency (SF) and wave area (SA, in μV × sec), assumed as a simplified index of the actual EEC power. From these values the average wave area, SA/SF, i.e., the quantal component of SA is calculated. By measuring the average wave frequency and by calculating SA/SF, different conditions, such as arousal reaction, druginduced EEG activation, seizures, and anesthesia can be easily distinguished and quantified. Moreover, this approach allows one to correlate the fundamental EEG parameters (wave frequency and SA/SF) with neurochemical signs of brain activity, such as the release of neurotransmitters from the brain. Thus, a more complete knowledge of the pharmacological profile of neuroactive compounds is made possible.

Lonetil is a new tranquilizer with great therapeutic range. With its influence on the pentylenetetrazol seizures, hypothermal effect and depression of provoked fight it is similar to the classic tranquilizers. The drug possesses also marked neuroleptic action: depression of orientation reflex and arousal reaction in case of RF stimulation, great antimorphine effect.

In 1954 Green and Arduini (13) reported the presence of approximately sinusoidal, high-amplitude, slow waves of 3–7 cps in the hippocampus of both curarized and freely moving rabbits. In the curarized rabbit, the slow waves appeared in response to natural sensory stimulation of electrical stimulation of certain subcortical structures. The waves appeared in the freely moving animal when it was alert and interested in its surroundings. The hippocampal slow waves were termed theta rhythm in keeping with the designation that had previously been established for human EEG components in the 4–7 cps frequency range, and the theta rhythm was characterized as an arousal reaction of the hippocampus.

Injections of solutions of procaine into the median parts of the septum region in rabbits have been performed. They can supress the regular pattern of hippocampal activity which occurs during an arousal reaction or after intravenous injection of physostigmine. This phenomenon was found to be entirely reversible. A slight deviation of the injection needle to one side of the septum causes only a homolateral effect. It is possible that the effect of procaine is partly due to a direct action of this substance on the nucleus of Cajal.

Experiments were performed on cats that carried implanted electrodes and in which reactivity was evaluated by presence of EEG “activation” in somatic sensory cortex. Animals were first exposed to repeated application of a “basic” tone until the latter became inoperant (“primary” habituation); subsequently, successive series of “test” tones, differing in frequency from the “basic” value and from each other, were presented (“secondary” habituation). As a consequence of having been accustomed to the “basic” tone, responsiveness of cats was modified in the sense that effectiveness of “test” tones near the “basic” value upon the pitch continuum was reduced in a selective manner. Reduction became manifest through two essential aspects, each suggesting different but complementary conclusions. 1. (i) On their first presentation, sounds removed from the “basic” value by at least 5 c/sec. in 200 were effective; those closer, ineffective. Specificity of habituation was thus limited by generalization of inoperancy to frequencies adjacent to the “basic” value. Notwithstanding this restriction, mechanisms mediating EEG “arousal” exhibited a relatively marked ability for differentiating between dissimilar pitches. 2. (ii) In successive series, initially positive tones became ineffectual following a staggered sequence in which values closer to the “basic” frequency achieved negativity earlier. Hence, the process that neutralized “basic” and, by generalization, adjacent tones, affected also other values: since ability to remain effective in the course of successive applications augmented as pitch separation from “basic” value increased, the impediment occurred in a decremental manner. Two features of habituation to tones were stressed: specificity and influence upon subsequent learning processes of similar kind. Both appeared related critically to the linear arrangement of tones upon the pitch scale.

A cause du comportement des indices polygraphiques et surtout du fait de provocation par des stimuli d'eveil, on conclut que le grincement des dents pendant le sommeil se manifeste comme une sorte de reaction d'eveil.

Publisher Summary This chapter compares the effects of atropine, scopolamine, and benactyzine against the electroencephalogram (EEG) arousal evoked by physostigmine in rabbits. The effects of atropine, scopolamine and benactyzine on the EEG traces are qualitatively similar and they differed only in the intensity of their actions. It is established that the effect of scopolamine exceeded that of atropine more than ten times. Also, benactyzine proved to be about twice as effective as atropine. These ratios of the effects of these three drugs are also in good agreement with the results obtained in behavioral experiments or with different central pharmacological effects. If the ratio for the central and peripheral anticholinergic effects of atropine, scopolamine and benactyzine is evaluated the specificity of the central effect of scopolamine and especially that of benactyzine is evident.

The effects of secobarbital and chlorpromazine were studied in monkeys trained on a continuous, rapidly presented successive discrimination task. The subjects were implanted with epidural electrodes to monitor EEG during drug-induced impairment of performance. The analysis was focussed on the phase of drug effect during which both drugs induced intermittent lapses of responding.

Rats with transected spinal cords showed electroencephalographic desynchronization and exhibited behavioral arousal in response to x-irradiation of the whole body of the head only, at dose rates between 0.5 and 1.5 roentgens per second. Neither arousal nor desynchronization occurred when only the body of the animal was exposed. Results indicate that neither the circulatory system nor the vagi are essential to the arousal reaction to x-irradiation.

Summary A spontaneous discharge-like wave in widespread cortical areas was induced by a strong click stimulation under very deep pheno-barbital anesthesia in cats. This phenomenon was facilitated by the destruction of the midbrain reticular formation and abolished after the bilateral destruction of the classic acoustic pathway up to the medial geniculate body. We believe that this phenomenon was a kind of arousal reaction and the mechanism by which this phenomenon produced was independent of Magoun's activating system in the lower brain stem.