The Role of the Functional Brain Asymmetry in the State of Subjective Perception during Interval Hypoxic Training

The analysis of the significant changes in coherence topography of bioelectric brain processes and the calculation of the correlation between the above processes and the parameters of gas exchange and external respiration showed that the role of brain asymmetry in the antihypoxic state occurred during interval hypoxic training (IHT). It was found that the main information-processing center was located in the left occipital region and that the right cerebral hemisphere was involved in antihypoxic state formation. The activation of the right cerebral hemisphere during IHT caused a particular state subjectively perceived as unrealized emotional excitation.     

Changes in the somatosensory evoked potentials in the night sleep of healthy subjects under conditions of preceding emotional stress

Somatosensory evoked potentials (SEP) were studied in eight healthy subjects in a state of alertness, in different stages of night sleep and also in night sleep after previous emotional stress. Characteristic changes of SEP were revealed in the second stage of sleep in delta-sleep and in the phase of rapid sleep. In conditions of emotional stress changes in SEP characteristics in periods of alertness and of night sleep were observed, expressed in the amplitude increase of a number of components. Asymmetry was revealed with predominance of the amplitude increase in the right hemisphere in the phase of the rapid sleep testifying to different roles of the cerebral hemispheres in processing of emotionally significant information. SEP changes in different functional states after the influence of emotional stress were considered as the reflection of non-specific activation increase possibly due to activation of the limbic structures in response to stress-producing stimulus.     

The delayed effects of systemic circulatory arrest on the free-radical processes in the brain structures of rats with different types of behavior in the emotional resonance test]

Male Wistar rats with different types of behavior in "emotional resonance" test ("active" and "passive") were studied one week after the global ischemia induced by cardiac arrest. Recovery of some physiological functions as well as free-radical-mediated processes and NO-synthase activity were studied in cerebral structures and blood serum. The "open-field" behavior normalized more rapidly in the "active" rats than in the "passive" ones, though the time course of the neurologic deficit compensation did not differ in these groups. A decrease in superoxide scavenging activity and in the content of 2-thiobarbituric acid-reactive material was revealed in the cerebral structures of both "active" and "passive" rats. Increased levels of free-radical generation in the hippocampus of the "passive" rats and in the cerebellum of the "active" rats were found. Higher NO-synthase activity was demonstrated in the cerebellum of the "passive" rats. Taken together, these data suggest that there are specific patterns of free-radical-mediated processes in the brain of rats with different types of behavior in "emotional resonance" test.     

Bases neuro-fonctionnelles des émotions: exploration en imagerie

Recent developments in functional imaging techniques, such as Positron Emission Tomography (PET) and functional Magnetic Resonance Imaging (fMRI), allow us to more precisely characterize the functional neuroanatomy mediating emotional responding. This corpus of studies is part of a new field of research labelled Affective Neuroscience. This paper reviews the studies investigating the neural substrates implicated in the processing of facial expressions and those implicated in the production of experimentally induced emotional responses. The implications of the results and the role of the cerebral structures that have been identified are discussed.     

Functional maturation of the brain and formation of the neurophysiological mechanisms of selective voluntary attention in young schoolchildren

A particular role was demonstrated for functional maturation of the frontothalamic system (FTS) of the brain in forming the cerebral organization of selective voluntary attention in ontogeny. Analysis of the coherence of the rhythmic components of the EEG α range in adults and seven-to eight-and nine-to ten-year-old children showed that, if the functional state of the control structures corresponds to the age, the formation of the neurophysiological mechanisms selectively modulating cortical activity and supporting selective tuning of the cerebral structures to the cognitive task is completed by the age of seven or eight years. Unlike adults, children demonstrated no interhemispheric features of the intercenter integration of cortical zones in the prestimulus period of voluntary attention. Children with a functionally immature FTS lacked selective specific integration of cortical zones in the pretuning period. The deficit of selective modulation of cortical activity in children with a functionally immature FTS is considered as the neurophysiological factor that delays the formation of voluntary attention and voluntary control of activity and, finally, leads to learning difficulties.     

Peculiarities of Formation and Reversibility of Neurogenic Stress-Related Emotional Disorders in Rats

In experiments on rats, we modeled neurogenic stress-induced emotional disorders (stress was evoked by repetitive nociceptive stimulation) and studied their peculiarities within the stressory and post-stressory periods. In these animals, drastic changes in the brain electrical activity and emotional behavior gradually developed; such changes were manifested over a long time period after cessation of the stressory influences. Our experiments demonstrated that tight and stable interrelations among brain limbic structures and negative hypothalamic emotional centers are formed under conditions of prolonged action of emotional stress. This results in the development of a protracted state of negative emotional excitation. The hippocampus is considered one of the key limbic structures responsible for the development of stable pathological stress-related reactions of the brain. Within the post-stressory period, we observed dramatic worsening of the general functional state of the animals, which developed in a parallel manner with intensification of the activity of the negative emotiogenic brain system. It is probable that the existence of periods of unstable equilibrium between oppositely directed emotional reactions in the dynamics of stress and after cessation of stressory influences is a common rule. Such periods reflect peculiarities of rearrangements in the adaptive brain mechanisms under conditions of a stable change in the mode of brain functioning in one particular situation or another.     

Lateralization of olfactory processes

Over the last ten years, methods of cerebral imaging have revolutionized our knowledge of cognitive processes in humans. An impressive number of papers dealing with cerebral imaging for olfaction have been published to date. Whereas the early works revealed those structures participating in the processing of odours presented passively to subjects, researchers later recorded brain activity when subjects performed specific olfactory tasks based on memory, emotion and identification. From these results, we suggest that there is a dissociation of olfactory processes, with involvement of the right hemisphere in memory processes and the left hemisphere in emotional processes. The review concludes with a summary of how these lateralized processes are consistent with the gestalt-nature of our olfactory perception.     

Identifying distinct components in the cerebral treatment of visual sexual information through functional neuroimaging

For now several years, the growing developement of neuroimaging techniques such as Positron Emission Tomography (PET) or functional Magnetic Resonance Imaging (fMRI) allowed a better understanding of neural processes involved in human emotions and goal-directed behaviors. In particular, several studies are now available on the neural correlates of male sexual arousal. A neurobehavioral model of neural processes involved in sexual arousal has been proposed (Redouté et al., 2000) comprising: i) a cognitive component; ii) an emotional component; iii) a motivational component and iv) an autonomic component. Among other regions, several cerebral areas have been found to be linked to: 1) the cognitive component which comprises: i) the orbitofrontal cortex involved in attentional processes directed toward the target and the superior parietal lobules; ii) the inferior parietal lobules involved in motor imagery processes; 2) the motivational component which involves the caudal part of the anterior cingulate cortex, related to motor preparation processes; 3) the autonomic component: concurrent measures of cerebral activations by functional neuroimaging and of erectile response by penile plethysmography allow the demonstration of the involvement of the hypothalamus, the insula, and the rostral part of the anterior cingulate cortex in this component.     

Formation of the head-trunk boundary in the animal body plan: an evolutionary perspective

Gene expression analyses and anatomical studies suggest that the body plans of protostomes and deuterostomes are phylogenetically related. In the central nervous system (CNS), arthropods and vertebrates (as well as their closest related phyla the urochordates and cephalochordates) share a nerve cord with rostral specification: the cerebral neuromeres in Drosophila, cerebral sensory vesicle of ascidians and lancelets and the large brain of craniates. Homologous genes, in particular of the otd/Otx and Hox families, are at play in these species to specify the anterior and posterior CNS territories, respectively. In contrast, homologies in the establishment of boundary regions like those separating head and trunk structures in arthropods or mid- and hindbrain domains in chordates are still unclear. We compare in these species the formation, properties and molecular characteristics of these boundaries during embryonic development. We also discuss recent findings suggesting that insects and vertebrates might have co-opted factors of related families to control the formation of these boundary regions, the evolution of which would then appear dramatically different from that of the anterior and posterior CNS domains.     

Agenesis of the corpus callosum: genetic, developmental and functional aspects of connectivity

Agenesis of the corpus callosum (AgCC), a failure to develop the large bundle of fibres that connect the cerebral hemispheres, occurs in 1:4000 individuals. Genetics, animal models and detailed structural neuroimaging are now providing insights into the developmental and molecular bases of AgCC. Studies using neuropsychological, electroencephalogram and functional MRI approaches are examining the resulting impairments in emotional and social functioning, and have begun to explore the functional neuroanatomy underlying impaired higher-order cognition. The study of AgCC could provide insight into the integrated cerebral functioning of healthy brains, and may offer a model for understanding certain psychiatric illnesses, such as schizophrenia and autism.     

A set of rehabilitation measures for compensating emotional stress

The physiological mechanisms of an integrated rehabilitation program and its constituent rehabilitation techniques, namely, local rhythmic thermal impulses; rapid autogenic regulation (RAR); and a session of slow, deep breathing, were studied in apparently healthy subjects who had experienced emotional stress. Mental arithmetic under the conditions of a time deficit with a reprimand was used as a model of emotional stress, which caused a number of rearrangements in the cerebral activity of the subjects, including enhanced β activity in the right frontal area and depression of slow EEG waves in the posterior cerebral areas, and promoted sympathetic influences and hemodynamic impairment. The set of rehabilitation measures, which was designed to affect the body as a whole, promoted the restoration of the initial cortical bioelectrical activity and autonomic status of the subjects. The mechanisms of each rehabilitation technique included in the program were determined.     

Appearance of parvalbumin-specific immunoreactivity in the cerebral cortex and hippocampus of the developing rat and gerbil brain

Summary Developmental changes in the distribution of parvalbumin-specific immunoreactivity in the brain, in particular in the cerebral cortex and hippocampus, were followed immunohistochemically in two different species, the rat and the Mongolian gerbil (Meriones unguiculatus) using an antibody raised against for rat parvalbumin. The gerbil is known to develop its auditory and visual capacity later than rat. In both the rat and gerbil, parvalbumin-specific immunoreactivity appeared after birth in both the cerebral cortex and hippocampus. The timing of the development of expression of parvalbumin varied among different parts of the cerebral cortex. The parietal cortex showed evidence of the earliest expression of parvalbumin whilst the occipital and temporal cortices expressed parvalbumin at a later stage of a development. This feature was common to both the rat and gerbil but occurred at a relatively later stage in the gerbil. The profile of the distribution of parvalbumin in the brain of the developing and adult gerbil was similar to that of the rat, but there were some differences. The frequency of bead-like structures on the dendrites of the parvalbumin-positive cells in the CA1 region of the hippocampus was markedly lower in the gerbil; instead, straight non-beaded fibers which ran vertically into the pyramidal layer were stained. Parvalbumin-positive fibers were also found in the cerebral cortex of the gerbil.     

Appearance of parvalbumin-specific immunoreactivity in the cerebral cortex and hippocampus of the developing rat and gerbil brain

Developmental changes in the distribution of parvalbumin-specific immunoreactivity in the brain, in particular in the cerebral cortex and hippocampus, were followed immunohistochemically in two different species, the rat and the Mongolian gerbil (Meriones unguiculatus) using an antibody raised against for rat parvalbumin. The gerbil is known to develop its auditory and visual capacity later than rat. In both the rat and gerbil, parvalbumin-specific immunoreactivity appeared after birth in both the cerebral cortex and hippocampus. The timing of the development of expression of parvalbumin varied among different parts of the cerebral cortex. The parietal cortex showed evidence of the earliest expression of parvalbumin whilst the occipital and temporal cortices expressed parvalbumin at a later stage of a development. This feature was common to both the rat and gerbil but occurred at a relatively later stage in the gerbil. The profile of the distribution of parvalbumin in the brain of the developing and adult gerbil was similar to that of the rat, but there were some differences. The frequency of bead-like structures on the dendrites of the parvalbumin-positive cells in the CA1 region of the hippocampus was markedly lower in the gerbil; instead, straight non-beaded fibers which ran vertically into the pyramidal layer were stained. Parvalbumin-positive fibers were also found in the cerebral cortex of the gerbil.     

Cardiovascular responses to emotional stress during activation of the brain imidazoline receptors

In alert normotensive and hypertensive (SHR) rats, effects of imidazoline receptor activating compounds of the central nervous system on the level of blood pressure, heart rate and value of arterial baroreceptor reflex at rest and in emotional tension, were investigated. It was shown, that the activation of the cerebral imidazoline receptors leads to an increase in the baroreceptor reflex value (both in resting and in emotional tension) and a decrease in the pressor reaction evoked by emotional affect. No data showing the role of imidazoline receptors in functioning of systems regulating of the initial level of blood pressure were obtained.     

Role of the pulvinar-lateralis posterior nucleus complex (P-LP) in the experimental epilepsy of the cat

The ability of the pulvinar-lateralis posterior nucleus complex (P-LP) to evoke epileptic activity when stimulated, was studied in 20 adult cats. Twelve animals were analyzed after they recovered from the surgical procedure (chronic model). In seven of them a cannula with electrodes was implanted in the P-LP and one twisted bipolar electrode was placed ipsilaterally in the following structures: hippocampus, superior colliculus, caudate nucleus and cerebral cortex. Through the cannula Na penicillin was injected. The electrodes allowed both to stimulate and to record the electrical activity. In the remaining five cats, the cannula was implanted in hippocampus in order to compare its sensitivity to generate epileptic activity to that of P-LP. Another group of eight cats were surgically implanted and studied in the same day (acute model). In four of them the cannula was placed in the P-LP through the temporal pathway, to avoid crossing the hippocampus and the ventricle. In another four, penicillin was injected in the P-LP after suctioning the cerebral cortex and the hippocampus overlying the former structure. Epileptic activity could be induced in P-LP and it spread rapidly to hippocampus and after a while to the other implanted structures. This was observed both with penicillin and electrical stimulation. The sensitivity of P-LP to generate epileptic activity was lower than that of the hippocampus. In particular, it was necessary to use two to ten times more penicillin and three times the electrical current intensity in the P-LP as compared to the values needed in the hippocampus. These results are discussed in view of the controversial problem about the ability of the thalamus to generate and spread epileptic activity.     

Towards the neurobiology of emotional body language

People's faces show fear in many different circumstances. However, when people are terrified, as well as showing emotion, they run for cover. When we see a bodily expression of emotion, we immediately know what specific action is associated with a particular emotion, leaving little need for interpretation of the signal, as is the case for facial expressions. Research on emotional body language is rapidly emerging as a new field in cognitive and affective neuroscience. This article reviews how whole-body signals are automatically perceived and understood, and their role in emotional communication and decision-making.     

A Shared Neural Substrate for Mentalizing and the Affective Component of Sentence Comprehension

Using event-related fMRI in a sample of 42 healthy participants, we compared the cerebral activity maps obtained when classifying spoken sentences based on the mental content of the main character (belief, deception or empathy) or on the emotional tonality of the sentence (happiness, anger or sadness). To control for the effects of different syntactic constructions (such as embedded clauses in belief sentences), we subtracted from each map the BOLD activations obtained during plausibility judgments on structurally matching sentences, devoid of emotions or ToM. The obtained theory of mind (ToM) and emotional speech comprehension networks overlapped in the bilateral temporo-parietal junction, posterior cingulate cortex, right anterior temporal lobe, dorsomedial prefrontal cortex and in the left inferior frontal sulcus. These regions form a ToM network, which contributes to the emotional component of spoken sentence comprehension. Compared with the ToM task, in which the sentences were enounced on a neutral tone, the emotional sentence classification task, in which the sentences were play-acted, was associated with a greater activity in the bilateral superior temporal sulcus, in line with the presence of emotional prosody. Besides, the ventromedial prefrontal cortex was more active during emotional than ToM sentence processing. This region may link mental state representations with verbal and prosodic emotional cues. Compared with emotional sentence classification, ToM was associated with greater activity in the caudate nucleus, paracingulate cortex, and superior frontal and parietal regions, in line with behavioral data showing that ToM sentence comprehension was a more demanding task.     

Sleep, emotions, and visceral control

It is known that sleep is connected with sensory isolation of the brain, inactivation of the consciousness and reorganization of the electrical activity in all cerebral cortical areas. On the other hand, sleep deprivation leads to pathology in visceral organs and finally to the death of animals, while there are no obvious changes in the brain itself. It is still unclear how the changes in the brain activity during sleep could be connected with the visceral health. We assumed that the same brain areas and the same neurons that, in wakefulness, process exteroceptive information, switch, during sleep, to the processing of the interoceptive information. Thus, the central nervous system is involved in regulating the life support functions of the body during sleep. The results of our experiments supported this hypothesis, explained many observations obtained in somnology, and offered mechanisms of several pathological states connected with sleep. However, at the present level of the visceral sleep theory, there is no understanding of the well-known link between the emotional reactions of the body and transition from wakefulness to sleep, and sleep quality. In this study, an attempt is undertaken to combine the visceral theory of sleep with the need-informational theory of emotions proposed by P. Simonov. The visceral theory of sleep assumes that in living organisms there is a constant monitoring of the correspondence of the visceral parameters to the genetically determined values. Mismatch signals evoke the feeling of tiredness and the need of sleep. This sleep need enters the competition with other actual needs of the body. In accordance with the theory of Simonov, emotions connected with a particular need play an important role in their ranking for satisfaction. We propose that emotional estimation of the sleep need based on visceral signals occurs in the same brain structures which undertake this estimation for other behavioral needs in wakefulness. During sleep, the same brain structures involved in estimating emotions continue to rank visceral needs and define their order for processing in the cortical areas and in the highest centers of visceral integration. In the context of the proposed hypothesis, we discuss the results of the studies on the link between sleep and emotions.     

Postnatal development of the scratch reflex in rabbits]

The development of the scratch reflex was studied in newborn (up to 2 months old) rabbits in norm and after elimination or activation of some parts of their nervous system (reticular formation, cerebellum, caudate nucleus, cerebral cortex, superior cervical sympathetic ganglia). The experiments with the section of the brain stem at the border between the medulla and the midbrain showed that in very young (5-10 days old) rabbits in norm the scratch reflex is controlled by the spinal cord with no influences of structures situated above the section's level. Later on the spinal mechanism of the scratch reflex becomes subject to supraspinal influences, among which in 2-3 weeks old animals facilitatory effects are predominant produced, in particular, by the reticular formation and the cerebellum, whereas in older age prevail inhibitory influences of the cerebral cortex, cerebellum, caudate nucleus and the sympathetic nervous system.