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This study was designed to test sleep efficiency while subjects were maintained on non-24-hr regimens of sleep and wakefulness. The regimens studied were 9, 12, 18, 30, and 36-hr sleep-wake cycles. In each regimen the ratio of sleep to wakefulness was held constant in a 1:2 ratio, i.e. there were 2 hfs of wakefulness for each hour of scheduled sleep. The amounts of sleep obtained under each experimental regimen were less than those obtained under the baseline days of 24 hrs. The sleep losses resulted both from an increase In the latency of sleep onset and increased wakefulness after sleep onset. The primary variables which resulted in less efficient sleep were schedule differences in prior wakefulness, circadian effects on the displacement of sleep onset times, a sleep termination effect, and the frequency of occurrence of the allotted sleep periods, in the short regimens the awake time after sleep onset was strongly associated with the degree to which prior wakefulness was reduced. In the longer regimens the principal sources of awake time were extended sleep length and a sleep termination effect. [ABSTRACT FROM AUTHOR]

A simple and inexpensive single channel analyzer is described which can simultaneously detect precise frequency bands in the EEG, operate a feedback loop, and feed an on-line multichannel analyzer capable of spectral analyzing period independent of amplitude above a variable feedforward threshold. [ABSTRACT FROM AUTHOR]

To investigate the effectiveness of informational feedback in the enhancement of the occipital alpha rhythm, 29 subjects were given one session of feedback in which either the presence of a tone signalled alpha (Loop 1) or the absence of tone signalled alpha (Loop 2), while 11 controls received no feedback. Alpha obtained during these conditions was compared to baselines established from maximum eyes closed rating alpha densities obtained in an earlier session. The Loop 1 group increased alpha across feedback trials but did not exceed baseline, while Loop 2 subjects exceeded baseline but showed little increase across feedback trials. Controls showed no significant change in alpha. Enhancement across trials was associated with individual differences in baseline alpha, with only those subjects in the mid-range of the distribution showing increases. These result do not verify claims large magnitude changes in alpha density with feedback training, but do suggest that methods of feedback presentation other than the customary Loop 1 contingency may be more effective in facilitating short term increases in alpha above resting baseline. [ABSTRACT FROM AUTHOR]

This experiment was designed to test the effects on subsequent sleep of a restriction in sleep length on the previous night. Eight male subjects were studied. After baseline recordings were made, sleep was restriction to either a period between 4-8 am or to a period between 6-8 am. On the night following the restriction of sleep the subjects retired at 11 pm and they were permitted to sleep ad lib in the morning. The restricted sleep periods resulted in differential sleep deprivation. Stages REM and 2 were markedly reduced whereas stages 3 and 4 showed little or no reduction in amount. There were significant reductions in sleep latencies and in the amount of time spent in stage 0 and 1. The first 8 hrs of ad lib sleep following the 2 restricted sleep periods did not differ in any significant way from the 8 hrs of baseline sleep. When sleep was permitted to continue until the subjects awakened spontaneously, the sleep after the restriction of sleep after the restriction of sleep to 2 hrs was significantly longer and displayed significantly more of stages REM and 2 when compared with the baseline ad lib sleep condition. The ad lib sleep period following the 4 hr condition showed similar changes although the differences were not statistically significant. The significant reductions in stages REM and 2 during the restricted sleep periods were attributed to the effects of reduced sleep length per se. The increases in sleep length and specially the increases in stages REM and 2 during the ad lib sleep periods were attributed to a differential sleep "debt" accruing from restricted sleep length. [ABSTRACT FROM AUTHOR]

Cortical evoked responses to the onset of angular acceleration (50°/sec2) were obtained from 20 Ss. The Ss were seated in a torsion swing chair (which provided the acceleration stimuli) and wore blindfolds and ear muffs. A discrimination task was used to keep Ss alert and enhance their attention to the onset of the vestibular stimulus. Ss were asked to judge whether the onset of rotation was smooth, having no detectable tactile sense (type A); or rough. with detectable tactile sensations (type B); or if tactile sense was detected in the absence of rotation (type C). Average evoked responses were obtained for each of these stimuli as well as for auditory stimuli. The most prominent and consistent feature of the responses obtained by rotation only (type A), here designated as rotary evoked responses (REPs), was a late negative-positive complex with peaks at about 193 and 345 msec respectively. On the bask or these latencics it is argued that the responses are probably of vestibular rather than sumatosensory origin. It is concluded that vestibular stimulation produces responses from the scalp comparable to those of other sensory systems and that the method or avenge evoked potentials is appropriate to studying vestibular-cortical pathways in man. [ABSTRACT FROM AUTHOR]

The present study was designed to investigate Sokolov's (1963) proposal that overextinction of the orienting response (OR) is related to sleep onset. A series of 80 auditory stimuli was presented to 22 male and female Ss. Although re-evocation of the skin conductance response (SCR) component of the OR occurred, in the majority of Ss, after 40-50 stimulus presentations, this was not accompanied by any change in cortical alertness as measured by integrated EEG output in three frequency bands (2-4, 4-8, and 8- 13 Hz). However, the results did indicate that Ss displaying SCR return required more stimulus presentations before initial SCR habituation and displayed more spontaneous fluctuations in skin conductance during the prestimulus period than did non-return Ss. Within the return group, latency of SCR return was negatively related to both spontaneous activity during the prestimulus period and number of stimuli to initial habituation. [ABSTRACT FROM AUTHOR]

In this experiment an attempt was made to determine which of a number of neuroelectric variables best predict the amplitude of the average evoked potential (AEP). Several EEG parameters derived from period analysis and amplitude integration of the primary trace, as well as the amplitude and latencies of single sensory evoked potentials, were treated with a stepwise multiple regression procedure. The amplitudes of certain components of the AEP were tested against the battery of independent variables (predictors) as separate criteria. The results of these analyses revealed that the amplitude of the single EPs accounted for the greatest proportion of variance in the AEP (each component measured). These data suggest that the size of the AEP is not dependent on spontaneous EEG fluctuations. [ABSTRACT FROM AUTHOR]

Two evoked potential tests of augmenting-reducing, using flash and sine wave modulated light stimuli, were administered to 23 normal Ss to determine: a) generalizability between tests; b) short-term reliability; c) influence of electrooculographic (EOG) activity; d) relationships between perceptual discrimination of stimuli and evoked response measurements; e) correlation between evoked responses, extraversion and neuroticism (Eysenck Personality Inventory). Four months later 11 Ss were retested before and after pilocarpine fixation of the pupil in miosis, to assess long-term reliability and pupillary factors. Although mean amplitudes of sine and flash responses were significantly positively correlated, correlations between linear slope measures of their intensity-response functions were low. Both short- and long-term reliability were high for mean amplitudes, but relatively low for most slope measures. Ocular factors, as reflected in EOG and changes with pupillary miosis, appeared to exert relatively little influence on the evoked potential measures of augmenting-reducing. Subjective perceptual discrimination performance was not correlated with evoked potential measures. Extraversion was correlated with some evoked response augmenting indicators; neuroticism yielded inconsistent results. Generally, results varied with lead placement. [ABSTRACT FROM AUTHOR]

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The neurotoxic effects of ticarcillin, methicillin, phenthicillin, oxacillin, cloxacillin and dicloxacillin were studied in the conscious rabbit. During and after intravenous administration of 1.2 and 2.4 g/kg, resp., over 50 min the blood concentrations of the drugs were determined and the neurotoxicity assessed by continuous recording of the electroencephalogram. The hydrophobia of the penicillins was characterized by determination of their partition coefficients between isobutanol and buffer solution pH 7.4. The penicillins showed quite different neurotoxic properties. A close correlation ( r=0.928) was found between the neurotoxic potency of the penicillins and their partition coefficients. With increasing hydrophobia the neurotoxic potency increased in the following sequence: Ticarcillin, methicillin, oxacillin, phenethicillin, cloxacillin, dicloxacillin. It can be concluded, therefore, that determination of the partition coefficient of a penicillin gives valuable information on the neurotoxicity to be expected. The introduction of a neurotoxicity quotient revealed that penicillins may be divided into two groups: less neurotoxic penicillins with a partition coefficient below 1.0 and highly neurotoxic penicillins with a partition coefficient above 1.0. [ABSTRACT FROM AUTHOR]

The effect of cerbral ischemia in the cat and of the treatment with nicergoline on the cerebral electrical activity has been described. Total cerebral ischemia for 3 min induces almost immediately an isoelectric EEG pattern; the end of ischemia is followed at 84 sec by the reappearance of the first electrical activity and at 16 min by its complete normalization pretreatment with nicergoline by the intravenous route (150 μg/kg) results in a significant shortening of the normalization times. Such effect is even more evident after the intracarotid administration of as little nicergoline as 15 μg/kg when both the reappearance and the normalization times are significantly reduced. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Neurology is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In 1874 Caton was the first to observe the electrical activity of the brain in animals. 50 years later Berger succeeded in recording an EEG from a human brain. Since then the electroencephalogram is been used principally for clinical neurological diagnosis. With the advent of the digital computer, attempts have been made over the past two decades to automate EEG interpretation. EEG analysis for long term monitoring purposes has only recently become feasible with the aid of modern computer technology. This study shows that the evaluation of background activity, performed repeatedly at fairly short intervals, is a parameter of prime interest in many clinical situations. Preliminary results indicate that on-line FFT techniques are highly useful in judging the trend and time course of the EEG background activity of patients suffering from brain lesions. [ABSTRACT FROM AUTHOR]

Recordings of the electroencephalogram (EEG) and the electromyogram (EMG) were collected continuously from rats equipped with permanent cortical and temporalis muscle electrodes. Automatic injections of mescaline were administered through indwelling i.p. cannulas at an initial dose of 30 mg/kg every 6 hrs for the first 2 days. This dose was then increased to 60 mg/kg/6 hr which was given for the duration of the study. The initial injections of the mescaline induced an immediate desynchronization of the EEG and behavioral arousal of the rat, which endured for 2-3 hrs. After this time, slow wave (SW) sleep and rapid eye movement (REM) sleep episodes reappeared, with the return of regular alternations of the sleep-wakefulness cycle. Upon continued administration of the drug, partial tolerance to the arousal effects of mescaline developed, which was reflected by a gradual reduction in the latencies to onset of SW sleep and REM sleep. Rats rendered tolerant to mescaline in this manner were found to be cross tolerant to lysergic acid diethylamide (LSD) and N,N-diethyltryptamine (DET). In contrast, cross tolerance did not occur to amphetamine, which exerts similar arousal and EEG desynchronizing effects. These results agree with physiological and behavioral studies of tolerance and cross tolerance among hallucinogens and support the usefulness of the EEG as a quantitative indicator of central nervous system functions. [ABSTRACT FROM AUTHOR]

Rats rendered chronically epileptic by the implantation of cobalt in the right parietal cortex were simultaneously prepared with permanent cortical and temporalis muscle electrodes for longitudinal EEG and EMG recording. Animals treated similarly with glass rods served as the controls. Wet dog shakes were quantified by counting the characteristic artifacts produced in the EEG tracings upon their appearance. The number of wet dog shakes exhibited by the control rats remained at a low and constant level over 18 days of recording. In contrast, wet dog shakes in the chronically epileptic rats began to increase by the fourth day after cobalt placement and remained significantly elevated up to the 18th day. Administration of reserpine to naive rats or to cobalt epileptic rats on days 7 and 9 after implantation resulted in an almost complete suppression of wet dog shakes which endured over a period of 3-5 days. These results suggest that the abnormally elevated wet dog shake response of the cobalt-epileptic rats and the spontaneous wet dog shake behavior of normal rats may be mediated by common neural pathways. [ABSTRACT FROM AUTHOR]

The effects of secobarbital and chlorpromazineupon behavior in a continuous, rapidly presented successive (go-no go) discrimination ('attention') task were evaluated in six Macaca mulatta monkeys. Simultaneous monitoring of EEG activity from epidural and subcortical electrodes permitted an evaluation of the nature of altered central nervous system events during erroneous performance (errors of omission) on this task. The computer-assisted analysis of pre-stimulus and post-stimulus EEG frequency activity (baseline crossings) suggests that the best measure of attentive behavior from the pre-stimulus EEG is percentage of beta 2 (25-40 cps) activity. No difference could be observed between drugs or among cerebral placements in this regard. This was determined by comparing measures of EEG frequency, pooled for a given test period, with performance from the same test period. On a trial-by-trial basis, however, the beta 2 measure in the pre-stimulus epoch failed to distinguish correct responses from errors of omission. Separation between correct responses and errors of omission is possible if comparisons are made between the changes in percentage of beta 2 activity in the pre-stimulus vs. post-stimulus epochs. For both drugs, the largest absolute change in beta 2 pre- vs. post-stimulus occurs with correct positive trials and the smallest change with correct negative trials. For secobarbital, no difference could be detected between correct and incorrect positive trials. For chlorpromazine, however, there was significantly less change in beta 2 for incorrect positive than for correct positive trials. The results were interpreted in terms of the hypothesis that secobarbital produces errors by depression of the general level of activation whereas chlorpromazine acts by reducing the sensory input which is necessary for correct discrimination performance. [ABSTRACT FROM AUTHOR]

These experiments examined in three strains of mice (Ha/ICR, Swiss Webster and C57BL/6J) the influence of pentylenetetrazol injections on: 1) brain seizure activity recorded from cortical electrodes, and 2) retrograde amnesia in an inhibitory avoidance task. In Ha/ICR mice, pentylenetetrazol administered after training impaired retention in doses that elicited brain seizures as well as in doses just below those which elicit brain seizures. The degree of retention impairment decreased with increasing training-treatment intervals. In Swiss Webster and C57BL/6J mice, doses of pentylenetetrazol which produced brain seizures did not affect retention. The results indicate that elicitation of brain seizures is not a sufficient condition for producing retrograde amnesia with pentylenetetrazol. [ABSTRACT FROM AUTHOR]

The effects of intraventricular injection of eledoisin and physalaemin in the rat were studied. Both peptides reduced explorative behaviour; eledoisin, but not physalaemin, produced catatonia, reduction of muscular strength, tremor and sialorrhea. The electrocorticogram showed the signs of a depressive effect both after physalaemin and eledoisin administration. [ABSTRACT FROM AUTHOR]

Three Rhesus monkeys were treated daily po with crude marihuana extract (CME) containing δ-THC 22-25%, cannabidiol 2-3% and cannabinol 2-3%, but no δ-THC. CME with the equivalent of δ-THC 12.5 mg/kg or more caused sedation, ptosis, ataxia, huddled posture, spontaneous jerky body movements and increased EEG synchrony without an initial phase of increased motor activity. Thereafter, δ-THC 12.5 mg/kg in 2/3 monkeys produced specific EEG changes including the appearance of protracted trains of 20-25 cps rhythmic activity in thalamus and cerebellar nuclei. δ-THC 37.5 mg/kg or more, in all 3 monkeys tested, caused 1.5-2 cps slow waves in hippocampus, amygdala and septum. Spikes or other epileptiform EEG activity were not observed. EEG manifestations after oral treatment were therefore different from those previously observed following i.v. injection or smoke inhalation. Behavioral effects consistently preceded and outlasted EEG changes, and tolerance developed more rapidly to specific EEG changes than to behavioral effects. The two monkeys that became tolerant after 50 daily treatments with δ-THC 37.5 mg/kg responded to termination of treatment with withdrawal signs manifested by increased aggressiveness. One of the two exhibited 'hallucinations' and increased periods of EEG desynchronization. Withdrawal signs were, therefore, more severe for behavioral than for EEG effects. [ABSTRACT FROM AUTHOR]

Chronic experimental epilepsy was produced in adult female Sprague-Dawley rats by the implantation of cobalt wire into the right parietal cortex. Rats treated similarly with glass rods were used as controls. All animals were simultaneously prepared with permanent cortical and temporalis muscle electrodes for EEG and EMG recording. Administration of pentylenetetrazol i.p. at a dose of 15 mg/kg every 15 min until the appearance of generalized convulsions resulted in the lowering of the chemical seizure threshold expected for the cobalt-treated rats, with only 2 injections of the drug required in contrast to the 3 to 4 injections needed for the control rats. Analysis of the EEG recordings collected over the 24 h period after the first injection revealed the presence of a more pronounced suppression of REM sleep in the cobalt-epileptic rats. This effect was found to be due to a reduction in the total number of REM sleep episodes, while the duration of the individual episodes remained unchanged. The latencies to REM onset in these rats, moreover, were markedly reduced. These results in a chronic seizure model further support the usefulness of cobalt experimental epilepsy in the rat for the study of human seizure disorders in comparison with acute seizure models. [ABSTRACT FROM AUTHOR]

Spontaneous (EEG) and visual evoked (V.E.P.) electroencephalographic activity have been longitudinally studied during acute alcohol poisoning in 8 young voluntary subjects; a comparison with i) neuropsychiatric state of the subject, ii) alcoholic haematic rate and iii) the time of reaction to different sensorial and sensitive stimulations has been made. A spectral EEG analysis has been carried out and the temporal behaviour of four main frequency bands has been studied. [ABSTRACT FROM AUTHOR]

Five volunteers slept 8 to 15 consecutive nights in the laboratory with electroencephalogram, chin electromyogram, and eye movements monitored by the method originated by Dement and Kleitman. δ-tetrahydrocannabinol (THC), 20 mg administered at bedtime decreased the amount of time spent in the REM or paradoxical phase of sleep. Abrupt withdrawal of THC after 4 to 6 consecutive nights of use produced a mild insomnia characterized by difficulty in falling and staying asleep but did not produce a marked REM rebound. [ABSTRACT FROM AUTHOR]

Copyright of International Archives of Occupational & Environmental Health is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The goal of this study was twofold: at which conceptional age do the spontaneous skin potential responses (SPRs) appear in premature infants; are they related to the sleep cycle as they are in human adults. Twenty nine sleeping infants, conceptional age (CA) 24 to 41 weeks, were investigated with polygraphic recordings. SPRs first appeared at 28 weeks. Their number increased rapidly after 30 weeks CA. They appeared mostly simultaneously with slow wave EEG activity which in premature infants is the EEG pattern of active sleep. Unlike the spontaneous SPRs which in adults occur mainly in NREM sleep, they are in premature and full term newborns well correlated with active (or REM) sleep. The relationships between spontaneous SPRs and autonomic or phasic events of sleep are also studied. [ABSTRACT FROM AUTHOR]

This study compared the conditioning of averaged evoked potentials in 1! psychotic and 11 normal children (57 experiments). Evoked potentials, like the blocking of alpha rhythm, can be conditioned by coupling a short sound of low intensity with an intense light flash. In normal children, the amplitude of the potential evoked by sound at the occipital region is small and quite variable. Its amplitude increases and its variability diminishes after coupling of sound and light. Also its form may resemble the potential evoked by light, especially in its rhythmic after-effects. In psychotic children auditory evoked responses are variable and small and remain so during the coupling of sound and light. Instead, these patients respond to the sound with a late slow wave, which is strong and generalized. It is particularly prominent during conditioning and resembles the slow waves which follow the visual evoked potentials in these autistic children. This slow wave can be experimentally reproduced in normal Ss by Psilocybine. It also resembles in certain ways the slow waves provoked by movement or its anticipation in normal Ss but it appears here during sensorial conditioning which requires no movement. We suspect that this slow wave may reflect a diffuse motor component in the perceptual and associative processes of these autistic children. [ABSTRACT FROM AUTHOR]

Electroencephalograms (EEGs) were recorded in a group of 37 normal boys aged 92-206 months during performance of a word-association task. Ss were instructed to say the first word that came to mind, as quickly as possible, following presentation of each of 18 stimulus words that were familiar to young children. Word-association latency, or the associative reaction time (RT), was analyzed only for trials in which a stimulus word evoked the same response word. Younger children were found to have significantly longer associative RTs than older children, with associative RT decreasing with increasing age according to a reciprocal power-law function. Comparison of this function with similar functions relating simple and disjunctive RT to age, suggested that the longer word-association latencies of children could not be attributed merely to developmental differences in non-verbal processes or processes concerned primarily with speed of responding. Sufficient EEG data for analysis were available for only 5 of the stimulus-response word combinations, and for these data, average EEG period from the left hemisphere was significantly different from (longer than) EEG period from the right hemisphere. Results of a partial-correlation analysis showed that left-hemisphere differences in EEG period between Ss can account, in part, for the relationship between associative RT and age, while righthemisphere differences in EEG period cannot. Although this suggested a hypothesis which ascribes the long word-association latencies of young children to age-associated differences in EEG period of the left hemisphere, evidence was inconclusive. [ABSTRACT FROM AUTHOR]

We investigated the relationship between the attention enhancement of the visual average evoked response (AER) and the S's ability to predict the,presentation of the attended stimulus. Twelve students were presented with sequences of two distinct visual stimuli while DC EEG and electro-oculogram (EOG) were simultaneously recorded. Stimuli were either regularly alternated (predictable) or randomly intermixed (nonpredictable). Verbal instructions directed S's attention and push button response to either one or both of the two stimuli. Interstimulus interval was held constant to permit computer averaging of the AER and the contingent negative variation. Selective attention enhanced the late positive component of the AER equally in the two conditions of predictability. Thus, it seems that the AER enhancement with intramodal selective attention does not depend on the S's ability to predict the presentation of the attended stimulus or to differentially arouse prior to its presentation. In the high predictability condition, the baseline EEG potential fluctuated with attention such that the AERs to the attended stimuli were negative relative to those to the ignored stimuli. [ABSTRACT FROM AUTHOR]

PP.T0007-0-ABCE-ST A computational procedure is presented which permits the measurement and averaging of physiological activity time-locked to a preceding voluntary event (e.g., the subject's operant behavior). The method allows the assessment of activity antecedent to any event on-line, i.e., during the course of an experiment; it may be used with any small general-purpose laboratory computer. Applications to electroencephalographic and electromyographic data are described. [ABSTRACT FROM AUTHOR]

The auditory evoked response (AER) to unpredictable stimuli was studied in 18 Ss. 100 msec sound bursts consisting of either a pure tone or white noise were presented every sec. One type of stimulus constituted the frequent expected stimulus and the other the infrequent stimulus that occurred as a random substitution. For the low probability (LP) stimulus condition, the mean ratio of infrequent to frequent was 1:30; for the intermediate probability (IP), 1:15; and for the high probability (HP), 1 : 7.5. Ss were instructed to ignore the sounds. The amplitude of a late positive wave (P3) of the AER was largest in the LP and smallest in the HP condition. There was a general decrease of all AER components over the course of a session. No evidence of dishabituation in the AER to the stimuli following the infrequent stimuli was obtained. The results of a detailed analysis of two orbital leads make it unlikely that eye movement or eye blink could account for the results. [ABSTRACT FROM AUTHOR]

In some recent reports, authors have found no evidence for habituation during sleep, and have concluded that habituation and sleep are incompatible. This finding was tested using skin potential, heart rate, and EEG responses to a 70 dB, 1 sec, 1000 Hz tone, in sleep stages 2, 4, and REM, with daytime controls. Interstimulus intervals used ranged from 10 to 30 sec. Autonomic responses analyzed separately for each series of stimuli showed significant habituation, except for heart rate responses in REM and in the daytime (drowsy) controls. EEG responses also demonstrated habituation. An interstimulus interval effect was found with EEG K-complexes, habituation occurring more slowly or not at all with the longer, irregular interstimulus intervals. It is suggested that previous failure to detect habituation has been due to a technique of averaging responses over hourly periods and/or the use of long irregular interstimulus intervals. It is concluded that habituation is indeed possible in human sleep if stimulus intervals are not long. [ABSTRACT FROM AUTHOR]

EEG delta activity during human sleep has a rhythmic pattern resembling a damped sinusoid with a period of about 100 min. Although the REM episodes coincide with the troughs of the delta cycle, the two rhythms are semi-independent. [ABSTRACT FROM AUTHOR]

The cortical evoked response in man to an amplitude modulated complex sound was investigated in order to find out whether the response reflects the acoustic spectrum of the stimulus or its modulation rate. The complex sound consisted of a train of square waves repeated 200 times a second and filtered so that only the acoustic energy confined predominantly to the region of 1000 Hz was delivered to the listener. Perceptually, the pitch of this complex sound is in the neighborhood of 200 Hz. The results from l0 listeners, tested repeatedly, showed that the presence of 1000 Hz tones interposed between successive presentations of the periodic complex stimulus served to habituate the response to the latter; intervening 200 Hz tones exerted relatively little effect on the responsiveness to the periodic stimulus. These data suggest that periodicity differences in stimulation at the periphery are not converted into place differences at the level of the auditory cortex; that a low-pitched sound is not necessarily mediated by those neural units maximally responsive to low frequency sinusoids. [ABSTRACT FROM AUTHOR]

Differences in the rate of increase of average evoked response (AER) amplitude with increasing intensity of light flash stimuli were studied in 80 male and 40 female college student volunteers. AERs to four intensities of light were recorded from the Ss and a measure of the rate of increase of AER amplitude with increasing stimulus intensity was obtained. Results from Ss tested twice, several weeks apart, showed that the slope of the amplitude intensity function was a stable individual characteristic. The observed amplitude intensity slope was greater in women than in men; vertex-ear leads showed lower slopes than vertex-occiput leads; subject handedness or hemisphere of lead derivation had little effect. Twenty extreme Ss, 10 individuals with the greatest slopes and 10 individuals with an actual decrease in AER amplitude with increasing stimulus intensity (negative slopes), were studied in greater detail. The amplitude-intensity slope was more affected by the absolute intensity of the light than the interstimulus interval or habituation effects. [ABSTRACT FROM AUTHOR]

The parietal-occipital EEG was recorded while subjects performed various fixation, accommodation and tracking maneuvers with stationary and moving targets. For some experiments the target was continuously in view and independent of the EEG; in others, a feedback path connected the occurrence of parietal-occipital alpha with the visibility of the target. The results show that alpha attenuation or blocking is not due to visual attention but to processes of fixation, lens accommodation, and pursuit tracking. Saccadic movements were not reliably linked to alpha or alpha blocking. [ABSTRACT FROM AUTHOR]

The experiment was designed to determine the value of measures of physiological activity as predictors of performance in a vigilance task. Subjects, for whom resting (EEG, heart rate, and skin conductance) and response (electrodermal) measures were available, were given an auditory vigilance task. Overall vigilance performance was significantly correlated with one measure of electrodermal habituation, latency of response to the first of a series of stimuli, and total number of responses to stimuli. None of the measures of resting physiological activity were significantly related to vigilance performance. The results are discussed in terms of Mackworth's (1969) theory of vigilance. [ABSTRACT FROM AUTHOR]

The response hierarchy of EEG and autonomic variables to tones of increasing intensity was studied during waking and sleep stages 2, REM, and SW (3 & 4 combined). Tones of 1000 Hz (5 sec duration, 55 sec ISI) were presented to 35 young adult male subjects. During waking, the tones began below awake auditory threshold and increased by 5 db until a motor response (button press) was made. During sleep, tones began at awake threshold and went to arousal threshold, i.e., motor response and/or an EEG change indicative of arousal. Changes in EEG, finger pulse amplitude, heart rate, skin potential, skin resistance, and respiration period were measured for each stimulus and were compared to a pseudostimulus response scored 25 sec prior to the actual stimulus. In the awake state, statistically significant responses (p < .05) were found for EEG, finger pulse, heart rate earlydeceleration, skin potential, and skin resistance to the tone at awake threshold, but not to tones at lesser db levels. During sleep, significant EEG responses were present to tones 30-25 db below arousal threshold, finger pulse 20-15 db below, and heart rate acceleration 20-5 db below. Significant skin potential, skin resistance, and motor responses were seen only at arousal threshold. Thus, in sleep, in contrast to waking, there were clear responses to stimuli below the arousal threshold, and there was definite ordering of the appearance of the various responses: EEG preceded the cardiovascular, with electrodermal and motor occurring only at arousal. This order was constant over sleep stages. Arousal thresholds were very similar across sleep stages in day sleepers (ap. proximately 35 db above awake threshold). The threshold during stage 2 for night sleepers was about 15 db lower than that for day sleepers. [ABSTRACT FROM AUTHOR]

Computer analysis of EEG data, recorded under both resting and work conditions following smoking, was compared to the appropriate control data in 6 male subjects. Following digitizing, a Power Spectral Analysis was performed which revealed significant reductions in the peak alpha frequency component up to 20 rain following smoking, during a visual task. Eyes open resting data showed a similar but not significant loss, after 8 min. No indications of increased fast activity were found. These results were related to comparable work on animals and humans. A suggestion was made as to the relevance of these changes. [ABSTRACT FROM AUTHOR]

This investigation was an attempt to study systematically the effects of uncertainty, or stimulus information, on habituation rate. Subjects were randomly assigned to one of three conditions varying in uncertainty. EEG alpha desynchrony duration, electrodermal conductance change, and reaction time were the dependent measures. The results showed uncertainty to have no significant effect on any of the neurophysiological measures. There was a significant effect on the reaction time measure. There was no significant correlation between the EEG and electrodermal response measures, nor was there any correlation between either of these measures and reaction time. Results indicated that habituation could occur in the presence of cortical and behavioral arousal. It was concluded that information may be most meaningfully measured behaviorally and that habituation parameters are dependent upon the physiological system being measured. [ABSTRACT FROM AUTHOR]

Three studies involving quantitative changes in alpha activity are reported. Sixteen normal volunteers were shown neutral or emotionally provoking words appearing with slowly increasing intensity on a frosted glass pane in a darkened room. A differential reaction was observed, i.e., with emotional words there was a higher alpha percentage from the time before the Ss perceived the light until after they could read the word. In the second study 10 normal volunteers were stimulated with closed eyes for 2-sec periods of diffuse light after the hypnotic suggestion of blindness. Compared with the prestimulus interval there was an average increase in alpha amplitude, whereas the control condition showed the usual alpha decrease during stimulation. In the third study 32 chronic schizophrenic patients were given a Phenothiazine derivative over 3 months after a 2-month placebo period. Ratings of alpha activity as to occipital amplitude, group length, topographical extension, and occurrence in synchronous groups showed a progressive increase from the placebo condition to the third month. [ABSTRACT FROM AUTHOR]

A late positive-going component (P[SUB3]) of the average evoked potential recorded from human scalp was shown to be quantitatively related to a priori stimulus probability both when the S was told the identity of the stimulus before it was presented and when the S was not told, and was instructed to guess. In the guessing situation, the amplitude of P[SUB3] was much larger and was influenced not only by the a priori probability of events determined by the experimenter but also by the interaction of these probabilities with the S's guessing behavior. The amplitude of the late positive component was inversely related to the proportion of trials in which a particular event was associated with a particular guess, i.e., the proportion of hits and misses. It was larger the more unexpected the outcome of the guess. This relationship held for different methods of manipulating the probability of two events. [ABSTRACT FROM AUTHOR]

The goal of this study was to develop an objective quantitative method for representing the temporal organization of sleep in terms of the period and rhythmicity of REM sleep occurrences. Data on normative human sleep, already scored for stage REM and not stage REM, were subjected to a "binary autocorrelation." The mean period over 92 nights of sleep for 10 Ss was 101.5 rain and quite stable. Data is also presented on variability of the rhythm in terms of an "index of rhythmicity." Measures of temporal organization may prove to be as significant for sleep research as amount of the various sleep stages. [ABSTRACT FROM AUTHOR]

The question is asked, can the same visceral changes occur in different states of consciousness. A survey of EEG and autonomic activity found in the awake state and during the various stages of sleep leads to the conclusion that the question must be affirmatively answered. The conclusion is reached that EEG and autonomic activity cannot be used to define states of consciousness. The state of consciousness of the subject must first be known before the physiological significance and possible behavioral meaning of the EEG and autonomic responses can be inferred. [ABSTRACT FROM AUTHOR]

The major purposes of this study were to test the effects of altering the typical home sleeping arrangement on subsequent laboratory sleep, to determine the nature of transient disturbances in EEG sleep patterns of habitual good sleepers, and to explore sex differences in sleep patterns of married couples. Twenty-eight married good sleepers slept three consecutive nights in the laboratory under both sleep-with-spouse and sleep-alone conditions. Continuous EEG and eye movement recordings were obtained throughout the seven hour bed period. Analyses of variance showed a significant increase in the amount of Stage 4 sleep and a significant decrease in REM sleep under the sleep-alone condition. Transient changes in sleep patterns of good sleepers were not associated with the usual correlates of poor sleep. Sex differences showed females with significantly more Stage 4 sleep, more total sleep, and fewer awakenings. It was concluded that the typical home sleeping arrangement may be a significant subject-selection variable in sleep and dream research. The major findings were discussed within the framework of a cortical homeostasis hypothesis. [ABSTRACT FROM AUTHOR]

The auditory evoked response was measured between the vertex and left ear in 9 Ss. In an extension of the idea of the recovery function, series of tones, including sets of 5 tone pips with ½, 1, or 2 sec between them, and 11 sec between sets, were presented, while Ss were instructed to press a button whenever there was a change in tone length. Because of the slow recovery of this response, no subtraction procedure was necessary. There were 6 runs representing 6 experimental conditions for each S. Habituation within runs was not observed, but there was significant habituation between runs in spite of a constant vigilance level. The evoked responses to the second and subsequent stimuli of each set were much smaller than to the first, depending on the interstimulus interval within sets. Evoked responses to 65 db stimuli were less than to 85 db, but showed proportionally the same changes with successive stimuli. [ABSTRACT FROM AUTHOR]

Two experiments were performed to explore further the relationship between the cortical slow potential change known as the "contingent negative variation" (CNV) and the concept of "expectancy." In Experiment I, 24 male Ss were presented click pairs, with inter-click intervals of 800, 1600 and 4800 msec (2 blocks of 10 trials each, counterbalanced between Ss for order), and instructed to press a key after the second click. Interval by order by trials analysis of variance showed interval to be the only significant factor: CNVs were lower and RTs longer as interval increased. In Experiment II, 8 female Ss given 60 pairs of clicks, 30 each with separations of 1200 and 2400 msec, were instructed to respond as in Experiment I, and were asked to make a pretrial prediction of the interval they would next receive. Analysis of variance of RTs showed that Ss responded slower when the interval was other than that predicted. Prediction by reception by subjects analysis of variance of CNV amplitude at the 1200 msec point gave a significant F only for prediction, mean amplitude for short being higher than for long. A similar design applied to CNV amplitudes at both the 1200 and 2400 msec points when Ss received the long interval yielded a significant measurement point by interval predicted interaction; at the 1200 msec point, short predictions were followed by higher CNVs than were long predictions; at 2400 msec, the opposite was found. These data combine with those already in the literature to indicate that the relationship between "expectancy" and the CNV is far from simple, and that cognitive and motivational factors play a significant role in determining CNV amplitude. [ABSTRACT FROM AUTHOR]

During stage REM sleep, eye movements were found to be distributed in discrete bursts of rapid eye movement (REM-bursts). REM-burst time averaged approximately 10 percent of stage REM sleep and the rate within a subject was consistent from epoch-to-epoch and night-to-night. Consistent subject biases in eye movement direction were also found. Within subject correlations were obtained between REM-burst time and autonomic activity. Significant positive correlations were found for respiration rate and number of finger pulse responses. There were positive but insignificant correlations with electrodermal activity, heart rate and decreases in respiration amplitude. Autonomic variability was not significantly associated with REM-burst time. [ABSTRACT FROM AUTHOR]

The number of nocturnal galvanic skin responses-(GSRs) varied widely between the electroencephalograph (EEG) stages of sleep as well as from night to night and from person to person. As others have found, non-specific GSRs occurred much more frequently during stage IV than other EEG stages, and were rare in stage REM. However, night-to-night variation and individual differences were related to the presleep state of the person. In general, electrodermai activity increased in all EEG stages as daytime stress increased, being especially great on nights preceding important school examinations. The nocturnal EEG profile was also related to the presleep state, the percentage of stage IV decreasing as daytime stress increased. The percentage of stage REM showed no systematic relation to stress. The occurrence of GSR "storms" during slow-wave sleep is consistent with the notion of release of cortical or other inhibitory influences during this state, but another mechanism is needed to explain the fact that presleep stress increases the frequency of GSRs in all stages of sleep, while simultaneously decreasing the percentage of slow-wave sleep. [ABSTRACT FROM AUTHOR]

Statistical analysis of baseline nocturnal EEG profiles identified two groups of Ss (a restless and quiet set) who differed in their performance efficiency under acute sleep deprivation. The restless group with less slow-wave sleep, more body movements, more awakenings, more transitions from stage to stage, and longer sleep latencies showed greatest sleep-loss decrement. On the first night of recovery sleep, the sleep profiles of the two groups were virtually identical, but by the third recovery night, the restless group was again showing signs of disturbed sleep. Within each group, all Ss had highly systematic stage-of-sleep cycles, forming Markov chains of at least order one. [ABSTRACT FROM AUTHOR]