Retention of orienting reaction habituation in chronic alcoholics

A polygraphic study on resistance to habituation of the somatic (EMG), autonomic (finger plethysmogram, galvanic skin reaction, respiration) and EEG (acoustic-evoked potential and EEG-blocking reaction) components of the orienting reaction, elicited by a repetitive auditory stimulus during successive (weekly) sessions was performed in 67 chronic alcoholics and in 70 matched normal subjects (control group). The study showed significant retention disturbances of orienting reaction habituation (i.e., of learning), or the "saving" of stimulations, achieved from one session to the other to obtain the habituation criterion, the savings being less in alcoholics than in control subjects. The severity of habituation retention disturbances depended on patients' ages, types of alcoholism, alcohol consumption intensity and chronicity, as well as the type of resting EEG.     

Habituation of orienting reaction in night terrors

A polygraphic study on resistance to habituation of the somatic (EMG), autonomic (finger vasoconstriction, galvanic skin reaction, respiration, pulse) and EEG (acoustic-evoked potential, EEG-blocking reaction) components of the orienting reaction elicited by a repetitive auditory stimulus was performed in 36 patients with night terrors and in 72 matched subjects in two control groups. The study evidenced a significantly higher resistance to habituation of the orienting reaction in patients with night terrors than in normal subjects (control group I) but significantly lower than in patients with symptomatic epilepsy (control group II). The severity of these habituation disturbances in patients with night terrors depended on the patients' age, the history of nocturnal events and their clinical form, as well as on the etiology of episodes. The habituation changes found in patients with night terrors may be ascribed to the nervous disorders of functional and/or organic nature which generated also the night terrors episodes.     

Disturbance in responsiveness in patients with post-meningoencephalitic epilepsy

A polygraphic study of the somatic, autonomic and electroencephalographic (EEG) components of the orienting reaction elicited by an auditory stimulus was performed in 29 patients with post-meningoencephalitic epilepsy and in 116 matched subjects in three control groups. Patients with post-meningoencephalitic epilepsy had a significantly more intense orienting reaction than control subjects, the degree depending on the seizure frequency, electroclinical form and history, as well as on the features of the EEG.     

Orienting reaction in patients with multiple sclerosis

A polygraphic study of the somatic (EMG), autonomic (finger plethysmogram, galvanic skin reaction, respiration, pulse, and EEG (acoustic-evoked potential and EEG-blocking reaction) components of the orienting reaction elicited by an auditory stimulus was performed in 71 patients with multiple sclerosis and in 74 matched normal subjects (control group). The study showed a significantly less intense orienting reaction in patients with multiple sclerosis than in control normal subjects. The severity of this responsiveness disturbance depended on the patients' age at symptom onset, major symptom types on admission, and the relapse frequency. The orienting reaction changes found in patients with multiple sclerosis may be ascribed to the diffuse demyelinating lesions in the nervous system of these patients, which generate, apart from the so polymorphous clinical manifestations of this disease, also important responsiveness disturbances.     

Nervous reactivity disturbances in patients with late post-traumatic encephalic syndromes.

A polygraphic study performed on 184 patients with late post-traumatic encephalic syndromes has shown marked nervous reactivity disturbances. The disturbances, estimated by testing for the electrographic components of the orienting reflex elicited by a repetitive auditory stimulus and for their habituation, were expressed by alterations in the intensity, resistance to habituation and sequence of habituation of the somatic, autonomic and EEG components. The character and severity of these disturbances depended on the mechanism behind the syndrome-inducing cranio-cerebral trauma, site of the impact and clinical picture of the syndrome.     

Multiple parameter comparative EEG analysis in alcoholism and narcotic dependence

Multiparametric comparative analysis of spatial organization of EEG was carried out in 137 alcoholics and 131 heroin addicts. Common and different deviations from normal EEG (105 control subjects) were found. Global alterations of EEG spatial organization were observed in drug addicts (as compared to alcoholics). Such changes characterized increasing synchronizing effects of mesolimbic and brainstem structures on the brain cortex. The ethanol effects were more specific and asymmetric. Changes in EEG spectral-coherence characteristics were revealed in all frequency band, however, maximal changes took place in the high-frequency theta in drug addicts and in narrow-frequency alpha subranges in alcoholics. Different effects on the high-frequency EEG component (19.00-21.25 Hz) and information-energy index (coherence-to-spectral power ratio) suggest the difference influence of ethanol and heroin on emotional-motivational and cognitive processes as well as the level of consciousness. The obtained data on EEG discrimination of alcoholism and drug addiction (the inverse problem solution) on the basis of "specific" EEG patterns appear to have considerable promise in development of systems of occupational selection.     

Changes in the brain's electrical activity during habituation to verbal stimulus in subjects with high and low levels of personal anxiety

Brain electrical activity during habituation to repeated verbal stimulus was recorded in subjects with high and low levels of personal anxiety. During habituation of subjects with low anxiety, the spectral power of EEG alpha and theta bands increased in the frontal cortical areas. Such a reaction was not observed in subjects with high anxiety level. Moreover, during habituation traces, the latency of P300 of the auditory evoked potential increased. This parameter did not depend on anxiety level. The amplitude of P300 in the right temporal region was shown to be related to anxiety level: it increased after habituation in subjects with low anxiety and did not change in subjects with high anxiety.     

Fast habituation of the long-latency auditory evoked potential in the awake albino rat

Fast habituation of the long-latency, vertex-recorded auditory evoked potential (AEP) peaks in humans was first described by Callaway (1973) as a reduction in AEP amplitude that occurs to the second of a pair of acoustic stimuli when both stimuli are presented with an interstimulus interval (ISI) of no more than 10 sec. When acoustic stimuli are presented in pairs with an ISI of 2 sec and an interpair interval (IPI) of approximately 10 sec, reduction in amplitude to the second tone occurs by as much as 30–50%. Fast habituation may depend somewhat on a subject's anticipation of the stimulus and on other factors related to attention and orienting. Studies in our laboratory have demonstrated this amplitude decrement to the second tone of a pair in human infants, children and adults and have explored the implications of this finding with respect to attentional processes and the allocation of cerebral resources. In the present investigation we describe an animal model of fast habituation. Here, vertex-recorded AEPs were obtained to paired tone stimuli delivered to awake adult male Sprague-Dawley rats chronically implanted with skull electrodes. Findings showed: (a) an AEP wave form with 8 distinct peaks, (b) for one component there was a marked decrement in amplitude from tone 1 to tone 2 in recordings obtained from an electrode placed slightly to the right of midline, and (c) that there were no significant differences in peak latencies across tones. This methodology may further our understanding of fast habituation in humans and may prove useful for studies of attention, orienting, and resource allocation using techniques that are not possible for use with human subjects.     

Cortical evoked potentials as indicators of auditory-visual cross-modal association in young adults

Auditory evoked potentials (AEPs) were studied from scalp locations Cz and Oz on 37 adults aged 20-22 years during sensori-sensorial association of a weak sound (S) and a strong flash of light (L). After sound alone repetition (habituation), S-L association modified AEP: first, it caused a generalized orienting response expressed as increasing of Cz and Oz amplitude AEPs. Then, this pattern gave way to an activation limited to the Oz lead: the increase of amplitude was then concomitant with shortened latencies when compared to sound-alone-habituated responses. Inter-individual differences were observed since these occipital modifications were recorded only on 26 subjects. The other 11 subjects did not exhibit any occipital modifications following S-L association. For them, the main modification was a strong decrease of Cz AEP induced by S-L association. These two groups also differed in their capacity to ignore irrelevant stimuli which is higher in the first group (AEP amplitude habituation with sound-alone repetition) than in the second one (no AEP habituation).     

Feedback control and quantification of the response of EEG alpha to visual stimulation

The response of the posterior EEG alpha rhythms to visual stimulation is so variable that it is difficult to obtain reliable on-line measurement of it. Feedback between the EEG alpha and the visual stimulus (1) reduces random variation in the response and (2) facilitates on-line quantification. With feedback EEG, the response to visual stimulation is measured as a series of time durations of alpha and of no-alpha intervals in the EEG. This time series occurs in two stages: an initial disturbance followed by a recovery. The quantification of the series of time durations is achieved by fitting curves to the series of alpha time intervals and of no-alpha time intervals. These functions, computed in each trial of 30 stimulations, are an objective, quantitative definition of EEG response. The utility of the method was demonstrated by testing it with reference to well-known effects. Habituation to a repeated stimulus, dishabituation, habituation to a class of stimuli, dishabituation by changing the class of stimuli, and differences among brain-lesioned, psychiatric patients and normals were shown with a detailed quantification. It was concluded that biofeedback is the method of choice for quantitative research on the EEG component of the human orienting response.     

Electrophysiological study of the choice motivation in man

In 70 Ss EEG coherence, amplitude and frequency characteristics as well as formal-dynamic (temperamental) properties were compared with the two dimensions of motivation involved in the choice of profession--its subjective "value" and the probability of its achievement ("accessability"). It was shown that the persons orienting themselves to the subjective value of the future profession tend to possess those features of temperament that testify to the stronger, more mobile and more labile nervous system as distinct from the subjects orienting themselves to the higher level of accessability. It was also shown that the persons with a higher level of the subjective value had a much higher level of EEG cortical activation in both hemispheres of the brain. The subjects with higher magnitudes of "accessability" were characterized by a lower level of brain activation.     

EEG of the interstimulus intervals during habituation of auditory evoked potentials in depressive moods

Averaging of EEG of interstimulus intervals in the process of study of habituation of auditory evoked potentials (EPs) in healthy subjects and patients with endogenous depression, revealed a rhythmic wave process (RWP) especially expressed in patients. RWP appeared and became stronger in successive averaging of 10 realizations completing each of four series of 30 clicks; often (especially in depressive patients) it was manifest in averaging of all 120 realizations with an amplitude comparable with that of main EPs components and even greater. A significant correlation was found of RWP parameters with characteristics of melancholic mood in both subgroups. It is suggested that RWP appears as a result of regular changes of EEG background during multiple stimuli repetition in connection with increased "slow" habituation and in a special manifestation of perceptive defence during depression including mechanisms of active isolation from external world.     

Effects of vasopressin on the habituation of the orienting reaction in men

Effects of arginine-vasopressin (AVP) on the habituation of the orienting reaction and response to stimulus mismatch were investigated in a between-group design with 40 healthy male volunteers using skin conductance and heart rate responses as dependent measures. Twenty-one 1000 Hz tones of 90 dB(A) intensity and 2 s duration were presented with alternating intervals of 20 and 140 s. Stimulus mismatch responses were analyzed to the tones after the long intervals and to a change of the interval duration. The expected prevention of habituation as an indicator of a general stimulus-related increase of phasic arousal under AVP could not be confirmed. There were no differences between the AVP and the placebo group in the skin conductance and heart rate responses. The interval change did not provoke a dishabituation reaction, but responses to the tones after the long intervals were reliably enhanced. However, AVP did not increase the reaction to stimulus mismatch. It is concluded that autonomic indicators of the habituation of the OR remain unaffected by AVP.     

Orienting reaction, organizing for action, and emotional processes

In the first half of the sixties, general notions were formulated concerning the functional role of the orienting reaction (OR) in adaptive activity, its elicitation and habituation. These notions included the following: a) The OR is elicited only by significant changes in a situation. This implies that OR elicitation is preceded by brain processes (usually unconscious) pertaining to the evaluation of the significance of changes according to an existing hierarchy of motivations, attitudes, and goals. Therefore, the OR is of an active (vs. reactive) nature, i.e., is inevitably determined by internal factors of brain activity. b) The OR is not a unitary reaction, but a complex polyfunctional activity, different aspects of which are reflected in different OR components which can be modified rather independently. c) The OR represents the processes of organizing new (non-standard) actions: sensory, motor, or intellectual. OR habituation is a manifestation of attenuation of the active control of an action, and an increase in its automation. Thus, the emphasis in understanding the OR has shifted from a predominantly "sensualistic" platform to a predominantly "actualistic" one. In recent experiments, the role of emotional processes in the elicitation and habituation of components of the OR has been analyzed. Complex relations between the GSR and anxiety were found in a study of patients with acute alcohol withdrawal syndrome treated with different psychopharmacological agents. The study of auditory evoked potential habituation in depressive patients has shown the emotional state influence on sensory aspects of the OR with the participation of the OR brain mechanisms in perceptual defense.(ABSTRACT TRUNCATED AT 250 WORDS)     

Modifications of EEG Related to Repeated Realizations of the Emotional Stroop Task

Multichannel recording of EEG in 11 subjects, who were three times subjected to the emotional Stroop task (in the presence of words with negative emotional loading, neutral words, and inhibitory verbal stimuli), demonstrated that the spectral power of the high-frequency subcomponent of the alpha-rhythm in the left hemisphere increased sequentially under these conditions. Modifications of EEG, in general, were indicative of noticeable transformation of informational flows related to the learning effect and decrease of the cognitive “pressure” due to habituation to the effects of emotionally neutral and inhibitory verbal stimuli. Data related to the EEG pattern agree with the results of measurements of a behavioral index (decrease in the time of sensorimotor reaction).     

Long-term retention of behavioural habituation in the rat

The orienting response in rats was measured by the interruption in licking that occurred during the presentation of a tone stimulus. Habituation occurred after a mean of 6·3 presentations and there was complete retention of habituation for 72 hr, and 70 per cent retention after 288 hr. This long-term storage involved in habituation distinguishes it from fatigue and supports the view that it must be regarded as a type of learning.     

Simultaneous biofeedback of heart rate and frontal EMG as a pretraining for the control of EEG theta activity

Following one base-line session, 20 normal subjects received four half hour sessions consisting of simultaneous feedback of heart rate and frontalis muscle (pretraining). Ten subjects received contingent (CF), the other ten noncontingent feedback (NCF). Subjects were asked to lower heart rate and frontal muscle tension (EMG). Heart rate within sessions decreased up to 19 bpm, with a mean of 4 bpm for the CF group. There was only a weak decrease over sessions, however, because of the strong habituation effect. The following events accompanied the heart rate decrease: (1) an increase of the variability of the heart rate, (2) a decrease of the variance of the EMG, (3) an increased correlation between heart rate slowing and EMG decrease, and (4) an increasing subjective experience of control of heart rate and EMG. After pretraining, subjects received eight sessions of auditory feedback of their frontal EEG theta activity (four sessions with CF and four sessions with NCF in balanced order). There was a weak increase of theta for the CF condition over sessions, but a decrease within the sessions. Pretraining on heart rate and frontal EMG control had no influence on the performance during theta training. It was hypothesized that control of heart rate slowing and theta control involve different mechanisms.     

Metabolic Effects of 2 Days of Strict Bed Rest

ObjectiveTo examine the possibility of whether 2 days of strict hospitalized bed rest would alter the metabolic profile (including insulin resistance as calculated by the quantitative insulin sensitivity check index or QUIC- KI) in both normal subjects and patients with type 2 diabetes in comparison with 2 days of normal activity.MethodsThe design of this pilot study was a randomized, crossover protocol that evaluated the effects of strict bed rest versus normal activity in 5 healthy normal subjects and 5 healthy patients with type 2 diabetes. All study participants completed a screening visit for assessment of baseline health.ResultsAll 10 study subjects completed the protocol without adverse events. Fasting plasma glucose, insulin, and C-peptide levels as well as several known risk factors for atherosclerosis were unchanged in both the subjects without diabetes and the patients with type 2 diabetes after 2 days of hospitalized bed rest. Insulin resistance demonstrated no significant change during the 48 hours of bed rest when compared with the mean value at baseline.ConclusionThis study demonstrates that 48 hours of bed rest has no significant effect on insulin resistance or standard metabolic variables in normal subjects and patients with type 2 diabetes. Therefore, achieving good glucose control in patients hospitalized for a period of 2 days or less does not necessitate early ambulation to prevent an increase in insulin resistance. (Endocr Pract. 2008;14:564-569)     

Electrical activity of the caudate body during the orienting reaction in dogs]

It has been shown that during an orienting reaction a delta-rhythm sets in in the dog EEG of the caudate nucleus head, which coincides with facilitation of the recruited rhythm in the auditory cortex EEG and inhibition of the motor activity. It has been assumed that the caudate nucleus head is involved in the processes of limitation of non-selective movements during orienting reactions.