Disruption of situational reflexes in experimental neurosis brought on by changes in the space factor

Motor activity elaborated in dogs and consisting of delayed choice reactions in a stochastic system (methods developed by Beritashvili, Hunter) and of rhythmic stereotypes of motor situational reflexes (Kupalov method) was not impaired by changes in spatial parameters of unconditioned stimulus in the stochastic system of choosing one feeding trough out of five. The changes in the spatial arrangement of conditioned and unconditioned stimuli in stable stereotypes led to changes in the behaviour of the animals and experimental neurosis with long-lasting disturbances in the situational conditioned reflexes and the short-term memory.     

The role of cholinergic mechanisms in memory processes in experimental neurosis in dogs

In experiments on dogs the role was studied of cholinergic mechanisms in memory processes at different stages of neurosis. Predominance was shown in initial state of M-cholinergic mechanisms which also in conditions of neurotic inhibition of conditioned activity decrease the level of functioning less than N-cholinergic link. In the postneurotic period excessive activity of N-cholinergic memory mechanism was revealed. The supposed mechanisms are discussed of cholinergic system disturbances in neurosis dynamics and possibility of their pharmacological correction.     

EMOTIONAL PROBLEMS IN CHILDREN—The Uses of Drugs in Therapeutic Management

Emotional disturbances in children may be due to an anxiety state, to obsessive-compulsive neurosis, to schizophrenia or to a brain injury causing a behavior disorder. Children in an anxiety state have difficulty in school because anxiety interferes with concentration, impairs memory and makes decisions difficult. Consequently, these children often fear school and express their anxiety by behavior disturbances which alienate them from parents and teachers.There are a number of chemotherapeutic agents physicians can use as a part of the treatment of emotionally disturbed children. Phenobarbital is valuable for short-term therapy for the anxious child. Meprobamate also may be prescribed for anxiety reactions. It is of limited value for the hyperkinetic and obsessive-compulsive child and of no value in the schizophrenic child. Atarax (hydroxyzine dihydrochloride) is beneficial for the neurotic and hyperkinetic brain-injured child. Children with severe anxiety reactions and schizophrenic disorders respond best to chlorpromazine or reserpine.It must be emphasized that drug therapy is a part of the total therapeutic attack on the emotional problems of children.     

Dynamics of the summary electrical activity of the dorsal hippocampus during development of experimental informational behavioral pathology

Dynamics of dorsal hippocampal EEG changes were traced in cats during the short-term memory loads under conditions of the time deficit between the separate delayed reactions. Shortening the intervals between the tests from 3-5 min to 15-20 s led to an expressed ECoG desynchronization accompanied by an initial increase and later blockade of the hippocampal theta-rhythm. Hippocampal theta-activity changes under conditions of the time deficit was a result of emotional stress. The long emotional stress impaired the short-term image memory, and this was manifested in hippocampal theta-rhythm disappearance.     

Luteolin Could Improve Cognitive Dysfunction by Inhibiting Neuroinflammation

Neuroinflammation and oxidative stress play an important role in cognition deficit following chronic cerebral hypoperfusion (CCH). Luteolin, a natural flavonoid found in many plants, is known for a variety of pharmacological activities, such as its anti-inflammatory, anti-allergy, urate, anti-tumor, antibacterial, and antiviral effects. To assess whether luteolin could prevent CCH-induced cognitive dysfunction, through its anti-inflammatory and anti-oxidative-stress effects, we used enzyme-linked immunosorbent assays, enzyme activity assays, behavioral methods, immunohistochemistry, and electrophysiology to detect neuroinflammation and oxidative stress, cognition alterations, and long-term potential (LTP), in a bilateral common carotid arteries ligation (2VO) rat model. We demonstrated that CCH increased tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), interleukin 6 (IL-6), and malondialdehyde (MDA), and decreased superoxide dismutase (SOD) and glutathione peroxidase (GPx) levels. Further, it caused microglia over-activation and astrogliosis, learning and short-term memory dysfunction, and an LTP deficit. Luteolin treatment reversed CCH-induced changes. Specifically, luteolin prevented the increase of TNF-α and IL-1β, IL-6, and MDA, improved the activity of SOD and GPx, inhibited microglia over-activation and astrogliosis (particularly in the hippocampus and cortex), and ameliorated learning and short-term memory dysfunction, and LTP deficit. Thus, our study suggested that luteolin could be a preferable anti-inflammatory agent to protect cognitive function and synaptic plasticity following CCH. Luteolin could also be putative therapeutic candidate for other inflammation-related brain diseases.     

Effect of psychotropic substances on conditioned reflexes in cats after emotional excitation]

Emotional rage and fear were found to destroy the differential inhibition and the short-term memory in cats. Stelazine, haloperidol, amitriptyline, imizine, chlordiazepoxide, diazepan and benactyzine prevented these disturbances. Chlorpromazine, as well as stelazine and haloperidol in high doses, enhanced these disturbances. The tranquillizers and the antidepressants normalized the higher nervous activity at a greater dose range than neuroleptics and were more preferable for the elimination of the negative consequences of the strong emotional reactions.     

Compensatory and antiamnestic effects of heptapeptide Selank in monkeys

The work presents results of study of role of heptapeptide Selank—an anxiolytic from group of biologically active peptides—in compensation of disturbed psychic and homeostatic functions in monkeys. New data have been obtained which indicate that an intranasal administration of Selank produces long-term changes of the monkey behavior disturbed during neurosis: elimination of fear and aggression and an increase of explorative activity as well as facilitation of handling reactions and communicational relations. It has been established that on the background of the Selank there occurs a long compensation of disturbed psychic functions (processes of memory) and of homeostatic parameters. It has been shown that unlike the earlier studied neurohormones (thyroliberin and ACTH_4?10), the antistress Selank effects do not depend on the type of neurotic disturbances and have long-term compensatory character. Comparison of the data obtained on monkeys with results of similar studies on the more low-organized mammals (rodents) allow suggesting that the new peptide preparation Selank is a promising agent for correction of various psychoemotional disturbances (alarm-and depression-like disorders).     

Short-term memory of motor network performance via activity-dependent potentiation of Na+/K+ pump function

Brain networks memorize previous performance to adjust their output in light of past experience. These activity-dependent modifications generally result from changes in synaptic strengths or ionic conductances, and ion pumps have only rarely been demonstrated to play a dynamic role. Locomotor behavior is produced by central pattern generator (CPG) networks and modified by sensory and descending signals to allow for changes in movement frequency, intensity, and duration, but whether or how the CPG networks recall recent activity is largely unknown. In Xenopus frog tadpoles, swim bout duration correlates linearly with interswim interval, suggesting that the locomotor network retains a short-term memory of previous output. We discovered an ultraslow, minute-long afterhyperpolarization (usAHP) in network neurons following locomotor episodes. The usAHP is mediated by an activity- and sodium spike-dependent enhancement of electrogenic Na(+)/K(+) pump function. By integrating spike frequency over time and linking the membrane potential of spinal neurons to network performance, the usAHP plays a dynamic role in short-term motor memory. Because Na(+)/K(+) pumps are ubiquitously expressed in neurons of all animals and because sodium spikes inevitably accompany network activity, the usAHP may represent a phylogenetically conserved but largely overlooked mechanism for short-term memory of neural network function.     

Age-related deficits of long-term memory in the crab Chasmagnathus

Short and long-term memory in adult crabs Chasmagnathus granulatus of different age are evaluated in two learning paradigms: habituation to a visual danger stimulus and appetitive conditioning. No difference between young, middle-aged and aged animals is found in short-term habituation with 15 training trials. A good level of retention of the habituated response at 24 h is exhibited by young and middle-aged crabs but a poor one by aged crabs. When the training-to-testing interval is lengthened to 48 h or the training session reduced to 7 trials, young and middle-aged crabs continue to show long-term habituation but aged individuals exhibit no retention at all. As regards appetitive conditioning, young, middle-aged and aged crabs present similar short-term memory with 5 training trials and similar long-term memory when tested at 24 h, but an age-related deficit in long-term retention is exhibited when the intersession interval is lengthened to 48 h or the training reduced to 3 trials. Thus, a reduction of long-term memory related to age is demonstrated in the crab Chasmagnathus. Since it is shown in two different learning paradigms, the possibility of explaining the deficit in terms of a failure in memory mechanisms due to aging rather than as a consequence of ontogenetic shift in the crab's behavior is discussed.     

Structural and functional reorganization of neurons and glia in the sensomotor cortex of the cerebral cortex in experimental neurosis

Histological and hypoxic changes in different tissue elements (neurones and glia), testifying to active disturbances of metabolic processes, are observed in the sensorimotor cerebral cortex of rabbits with experimental neurosis. These changes indicate a complex structural-metabolic rearrangement, occuring with this form of CNS pathology. The results of the study may be used for investigation of mechanisms compensating disturbances in the higher nervous activity and for pathogenetically grounded therapy.     

P300 component changes of the auditory event-related potential in the patients with typical and atypical panic attacks

84 patients with panic disorders and 36 healthy control subjects with use of clinico-neurologic technique, psychometric, neuropsychological and the neurophysiological method of auditory event-related potentials P300 were examined. Patients with panic disorders were characterized by the raised level of anxiety, depression and cognitive function disturbances in the form of decrease of short-term memory and attention insufficiency in comparison with the healthy control subjects. Patients with atypical panic disorders differed from the patients with typical panic disorders by lower level of anxiety, a greater degree of depression and more expressed cognitive function disturbances. In comparison with the healthy control subjects with atypical panic disorders the decrease of P300 peak amplitude was observed, with typical--its augmentation. It is supposed, that P300 peak change is bound to dysfunction of temporal-limbic-reticular brain structures.     

The reactivity of the hypophyseal-adrenal system in rats with different forms of adaptive behavioral pathology]

The dexamethasone suppression test (DST) was applied to male Wistar rats with different models of depression: group with the learned helplessness, group with informational neurosis provided by time-deficit conditioned avoidance training, as well as groups of rats of two strains selected for low (KLA)--and high (KHA) avoidance learning. The pre-dexamethasone basal and stress-induced corticosterone levels were similar in intact rats and those exposed to inescapable shock. The dexamethasone administration (5 mkg/kg) failed to decrease the serum corticosterone level in rats with learned helplessness. The informational neurosis increased significantly the basal corticosterone level and decreased the stress response. Serum corticosterone levels were similar in KLA and KHA rats. These results give evidence that two stress-induced rat models of depression with similar behavioural disturbances (reduction of escape/avoidance reactions) exhibit marked differences in the activity of hypothalamo-pituitary-adrenal (HPA) axis.     

Behavior and neurotoxic consequences of lead on rat brain followed by recovery

Long-term exposure to lead has been shown to produce behavioral disturbances in human and animal models. These disturbances are shown to be associated with alterations in cholinergic and dopaminergic neurotransmission in the central nervous system. The present experiment was designed to study the effect of lead exposure on neurotransmitters like dopamine, serotonin, norepinephrine, and activity of acetyl cholinesterase along with alterations seen in memory and locomotor functions. Lead was administrated orally in a dose of 50 mg/kg for 8 wks on alternate days and a study was done at the end of exposure and also after 8 wk of recovery. Lead exposure reduced the brain and body weight, which, however, did not improve even after recovery of 8 wk. The alterations seen in the various transmitters also remain unchanged at the end of recovery. Lead exposure for 8 wk affected the locomotor and cognitive functions as assessed by the rota rod treadmill and active avoidance test. However, following a recovery period, a significant improvement was seen in locomotor as well as cognitive behavior. The short-term memory as assessed by the passive avoidance test remains unchanged both following lead exposure as well as recovery.     

Impaired mismatch negativity (MMN) generation in schizophrenia as a function of stimulus deviance,probability, and interstimulus/interdeviant interval

Schizophrenia is a severe mental disorder associated with disturbances in perception and cognition. Event-related potentials (ERP) provide a mechanism for evaluating potential mechanisms underlying neurophysiological dysfunction in schizophrenia. Mismatch negativity (MMN) is a short-duration auditory cognitive ERP component that indexes operation of the auditory sensory (`echoic') memory system. Prior studies have demonstrated impaired MMN generation in schizophrenia along with deficits in auditory sensory memory performance. MMN is elicited in an auditory oddball paradigm in which a sequence of repetitive standard tones is interrupted infrequently by a physically deviant (`oddball') stimulus. The present study evaluates MMN generation as a function of deviant stimulus probability, interstimulus interval, interdeviant interval and the degree of pitch separation between the standard and deviant stimuli. The major findings of the present study are first, that MMN amplitude is decreased in schizophrenia across a broad range of stimulus conditions, and second, that the degree of deficit in schizophrenia is largest under conditions when MMN is normally largest. The pattern of deficit observed in schizophrenia differs from the pattern observed in other conditions associated with MMN dysfunction, including Alzheimer's disease, stroke, and alcohol intoxication.     

NMDA-Receptors in the central nervous system of the honey bee with kynurenine deficiency

Effects of some drugs on the short-term memory were tested. In kynurenine deficit, mutant snow laranja manifested the same pharmacological profile and 10 to 100-fold enhancement of sensitivity of the NMDA receptors' different sites. The data obtained suggest that the gene controlling the key enzyme activity of the kynurenine pathway of tryptophan metabolism is involved in regulation of the CNS NMDA receptors' functional condition. The kynurenines may be classified as endogenous modulators of the NMDA receptor sensitivity.     

Stages in the development of neuroses in the dog and effects of preparations with antidepressive and tranquilizing properties

In modelling of neuroses, successive stages of development of this pathology were observed in dogs. The first stage is characterized by circular disturbances of conditioned activity, vegetative shifts of compensatory character and intensification of individual characteristics of behaviour. At the second stage, parallel with sharp disturbances of conditioned reflexes and with vegetative dystonia, a distortion of emotional reactions was observed in dogs. It is essential that resumption of neurotization episodes in experiments on dogs with the second stage of disease promoted a development of depressive-like states. Diazepam corrected the behavioural and vegetative shifts at the first stage of neurosis. Non-typical antidepressants eliminated the manifestation of symptoms complex of the disease, especially at prolonged treatment.     

Single bout of exercise eliminates the immobilization-induced oxidative stress in rat brain

We were interested in the effects of immobilization (IM), a single bout of exercise (E) and immobilization followed by exercise (EIM) on memory and oxidative damage of macromolecules in hippocampus of rat brain. Eight hours of IM resulted in impairment of passive avoidance test (memory retrieval deficit) and increased latency to start locomotion in an open-field test. Two hours of swimming did not significantly alter the memory retrieval deficit and latency, while the EIM group had longer latency and similar memory than control and E groups. The oxidative damage of lipids, proteins and nuclear DNA increased significantly in IM group and no increase was observed in E and EIM animals. The activity of proteasome was not altered in any groups. The activity of glutamine synthetase (GS) was decreased in IM group (P < 0.05), this down regulation was not observed in E and EIM groups. These data suggest that oxidative damage of macromolecules is associated with impaired cognitive function. Single bout of exercise after immobilization eliminates the oxidative damage of macromolecules and normalizes memory function, probably by its ability to restore the activity level of GS and eliminate the consequences of immobilization-induced prolonged efflux of glutamate.     

The use of endogenous <Emphasis Type="Italic">P</Emphasis>300 event-related potentials of the brain for assessing cognitive functions in healthy subjects and in clinical practice

Assessment of higher mental functions, objective detection of cognitive impairments, and investigation of pathophysiological mechanisms underlying these impairments in various neuropsychological diseases are of great importance for neuropsychophysiology. The endogenous event-related potential (ERP) approach is one of the instrumental neurophysiological methods that are currently used for assessing these complicated processes because recorded potentials reflect the intrinsic brain activity and changes in these potentials are caused by endogenous factors of the brain activity. The P300 cognitive evoked potential, induced by selective attention to a stimulus, has been the most widely used endogenous ERP. This potential may be helpful for studying mechanisms of mental disturbances, as it reflects neuronal processes connected with nonspecific activating reticulothalamic systems, as well as with limbic and neocortical mechanisms of selective attention and short-term memory.     

Effects of voluntary control of the functional state on the organization of cortical processes during mnemenic activity in schoolchildren aged nine to ten years

In schoolchildren aged nine to ten years, the analysis of EEG indices (spectral power density, the function of coherence in the α band) of different cortex regions in four experimental situations—quiet wakefulness, mnemenic activity, relaxation, and mnemenic activity in the postrelaxation period—was performed. In the mnemenic activity situations, a task for determining the short-term auditory-speech memory span was used. A positive effect of relaxation on the efficiency of mnemenic activity expressed in an increase in the short-term memory span was found. Comparison of groups formed according to the increase in the memory span showed differences in the dynamics of coherence indices. Only in children with a pronounced postrelaxation increase in the memory span in the situation of mnemenic activity was an increase in coherence in the high-frequency subrange of the α band of the EEG detected, whose functional significance is related to selective inhibition.