On Disturbances of Interhemispheric Interaction in Psychopathologic States (Development of Ideas of L.Ya. Balonov and V.L. Deglin)

The current state of the problem of changes of brain functional asymmetry in psychopathology is reviewed from the point of view of disorders of interhemispheric interaction as the main chain in genesis of affective disorders and schizophrenia. Based on studies of individual activation of the left and right hemispheres as well as on evaluation of cognitive activity, it is shown that psychopathology is accompanied by a disorder of hemispheric interaction with shift of the interhemispheric activation balance towards the right hemisphere in depression and towards the left hemisphere in maniacal states and paranoid schizophrenia. Changes of the activation balance lead to disorder of cognitive activity and human adaptation in the environment. A conclusion is made that disinhibition of subcortical and brainstem structures in psychoses occurs not only vertically, but also horizontally, when the complementary and superpositional interaction of hemispheres shifts to the evolutionary earlier reciprocal type of interaction with domination of cognitive functions of the right hemisphere in depression and of the left hemisphere in the maniacal state and schizophrenia.     

Contribution of L. Ya. Balonov and V. L. Deglin to Study of Verbal-Thinking Activity from the Viewpoint of Functional Brain Asymmetry

This paper summarized experimental data on the role of the right and left brain hemispheres in performance of the verbal and thinking activity, which were obtained by Lev Yakovlevich Balonov and Vadim L'vovich Deglin and published in numerous articles and monographs. The interpretation of these results, the concepts of Balonov and Deglin on regularities underlying division of functions between two hemispheres and on mechanisms of the hemispheric interaction are presented. The original concept is exposed, which consists in that the functional brain asymmetry is based on different relation of the right and left hemispheres to the language sign, its different vision and perception by each hemisphere. The data of study on the functional brain asymmetry also helped the authors to find answers to the questions concerning general scientific and general human problems dealing with the conscious and the unconscious, speech development in child, evolution of psychic activity. The authors understood clearly that the answers to these questions ...by no means will be exhaustive... and that ...this is merely one of possible points of view.     

Hemispheric specialization in dogs for processing different acoustic stimuli

Considerable experimental evidence shows that functional cerebral asymmetries are widespread in animals. Activity of the right cerebral hemisphere has been associated with responses to novel stimuli and the expression of intense emotions, such as aggression, escape behaviour and fear. The left hemisphere uses learned patterns and responds to familiar stimuli. Although such lateralization has been studied mainly for visual responses, there is evidence in primates that auditory perception is lateralized and that vocal communication depends on differential processing by the hemispheres. The aim of the present work was to investigate whether dogs use different hemispheres to process different acoustic stimuli by presenting them with playbacks of a thunderstorm and their species-typical vocalizations. The results revealed that dogs usually process their species-typical vocalizations using the left hemisphere and the thunderstorm sounds using the right hemisphere. Nevertheless, conspecific vocalizations are not always processed by the left hemisphere, since the right hemisphere is used for processing vocalizations when they elicit intense emotion, including fear. These findings suggest that the specialisation of the left hemisphere for intraspecific communication is more ancient that previously thought, and so is specialisation of the right hemisphere for intense emotions.     

Rearrangement of the Prefrontal Cortex Neural Activity in Both Hemispheres during Learning

Neuronal activity of both right and left hemispheres of the rat prefrontal brain cortex was recorded in the two-ring maze during animal learning to operate in response to signals. At the beginning of learning, pairwise comparison of neural activity that accompanied correct and incorrect choice of the right and left sides showed significant differences in the left hemisphere and the lack of differences in the right one. With increasing percentage of correct choices during a session of learning, the differences in neuronal responses appeared in the right hemispheres and were reduced in the left one. The opposite trends in rearrangement of the total impulse activity are believed to be related to different roles of hemispheres in the construction of the internal behavioral model.     

Modern view of cortical control of posture and brain asymmetry: a literature review

Review concerns cortical mechanisms of postural control. Data on different role of the right and the left cerebral hemispheres in postural control are analyzed. These data are compared with the data on lateralization of perception and action. Peculiarities of sensory perception and motor control in the right and the left hemispheres are supposed to be connected with the specialization of the left hemisphere on the dynamic tasks and of the right hemisphere on the static tasks which include orthograde posture control in human beings.     

EEG study of the functional organization of the right and left hemisphere during solution of verbal and spatial problems

In adult healthy right-handed subjects, the expression and degree of synchronization of the EEG alpha-range rhythmic components in different areas of the right and left hemispheres, were studied in a state of quiet wakefulness and during solving of verbal and spatial tasks presented in the visual field. The EEG of quiet wakefulness was characterized by different distribution of the alpha-range rhythmic components in the right and left hemispheres; in the right hemisphere low frequencies (7.5-10.5 c/s) were more expressed and more coherent; in the left one--the high frequencies (10.5-13.5 c/s). The solving of tasks was accompanied--along with a decrease of the whole alpha-range power spectra both in the right and the left hemispheres--by a local increase of synchronization of certain components of this range; the increase was specific to the hemisphere and the kind of task. The increase of synchronization of low-frequency components was observed in the right hemisphere during solving of the spatial task and that of the high-frequency components was noticed in the left hemisphere during solving of the verbal task. On the basis of the data on hemispheric specificity of electric activity synchronization of the alpha-rhythm, a suggestion is made about a different character of the functional integration of the structures of the right and left hemispheres in the process of solving of spatial and verbal tasks.     

Functional asymmerty of the brain and emotions

Different kinds of emotional phenomena are related in a different way with the workings of the left and right hemispheres of the brain. Emotional reactions (phasic emotions), which appear on the basis of a cognitive loading (mental representation, recognition, play, prognostication, watching movies, reading of emotionally colored texts or separate words and so on) and which are tested with the help of electrophysiological methods, activate different regions of the left and right hemispheres of the brain depending on the complexity and novelty of emotiogenic situations as well as on the degree of subject's emotional tension. The tonic emotions individual background-mood, on which depends the emotional estimation (negative of positive) of the presented stimuli or events, are determined mostly by a prolonged, relatively stable, tonic activation of each hemisphere connected with subjects' individual characteristics. The predominance of the left hemisphere activity creates positive emotional background, whereas the predominance of the right hemisphere creates negative background.     

Assessment of recognition of emotions by healthy persons and patients with focal brain pathology

To assess the involvement of different structures of the human brain into successive stages of the recognition of the principal emotions by facial expression, we examined 48 patients with local brain lesions and 18 healthy adult subjects. It was shown that at the first (intuitive) stage of the recognition, premotor areas of the right hemisphere and temporal areas of the left hemisphere are of considerable importance in the recognition of both positive and negative emotions. In this process, the left temporal areas are substantially involved into the recognition of anger, and the right premotor areas predominantly participate in the recognition of fear. In patients with lesions of the right and left brain hemispheres, at the second (conscious) stage of recognition, the critical attitude to the assessment of emotions drops depending on the sign of the detected emotion. We have confirmed the hypothesis about a correlation between the personality features of the recognition of facial expressions and the dominant emotional state of a given subject.     

Role of the Right- and Left-Hemispheric Structures in Speech and Memory Formation in Children

The role of structures of the left and right cerebral hemispheres in formation of speech function and memory was studied on the basis of complex examination of children with developmental speech disorders. On the basis of EEG estimation of the functional state of the brain, children were classified in two groups depending on the side of localization of changes in electrical activity: those with local changes in electrical activity in the left hemisphere (group I) and those with changes in the right hemisphere (group II). The medical history suggested that the observed features of topography of local changes in electrical activity were linked with the character of prenatal and labor complications and their consequences leading to embryo- and ontogenetic disorders in development of different brain regions. Comparison of the results of neuropsychological examination of the two groups showed that different regions of the brain cortex of both the left and right hemispheres are involved in speech formation. However, a specific role of the right hemisphere in formation and actualization of automatic speech series was revealed. It was suggested that the integrity of gnostic functions of the right hemisphere and, primarily, the spatial organization of perception and movements is a necessary factor of development of auditory–speech and nominative memory.     

Characteristics of the perception and imagination of emotions in patients with focal brain pathology

Voluntary components of the emotion perception were shown to be related to the left hemisphere temporal area in patients with focal lesions of postero-frontal and temporal areas of both hemispheres, whereas the involuntary components required involvement of the right hemisphere temporal area. The voluntary components of the emotion reproduction are associated with involvement of the left hemisphere postero-frontal area, whereas involuntary components of perception are related to work of the right hemisphere postero-frontal area. The data obtained suggest that the voluntary (conscious) recognition and reproduction of emotions are mainly related to the sensory and motor speech centres of the left hemisphere, whereas involuntary those involve symmetrical areas of the opposite hemisphere.     

Lateralized ultradian rhythms of the right and left brain: temporal variations of tactile discrimination tested in German subjects.

Endogenous ultradian rhythms with a periodicity of 2-3 hours operate separately in the right and left hemispheres of the human brain and modulate physiological functions, perception and cognition. Since sensory pathways from either hand terminate in the contralateral hemisphere, ultradian rhythms of the right and left brain can be monitored by variations in the tactile discrimination of the left and right hand, respectively. Thirteen right-handed German males were tested every 15 minutes for 8 hours. Time series of the tactile error rate determined for the right and left hands oscillate with significantly different ultradian periodicities. Whereas cycles in tactile discrimination of the right hand (left hemisphere) have a periodicity of about 2 hours, tactile discrimination of the left hand (right hemisphere) is modulated by longer periods of about 3 hours. This is interpreted in terms of the overall functional asymmetry of the human brain. Since the left brain is the specialized locus for verbal processing and the right brain for visual-spatial processing, lateralized ultradian rhythms operating in the hemispheres may provide a distinct frame for long-term timing of neuronal processes underlying semantic and spatial mapping of the environment. This is particularly important for interpreting biosocial behavioural rhythms seen in humans living under natural conditions.     

Sex differences in the relationship between creativity and hemispheric information selection at the global and local levels

Sex-related differences in creativity-related hemispheric selective processes at the global and local levels were studied using hierarchically presented letters under the conditions of their identification and comparison. The results showed that, irrespective of the sex and the type of creative thinking, its originality was associated with the acceleration of right-hemispheric processes of information selection at the global level and deceleration of interhemispheric communication. Relationships between the originality of ideas and hemispheric attentional characteristics were stronger in men during the solution of verbal creative problems and in women during figurative original thinking. The originality of verbal activity in men was more closely associated with the success of selective processes in the left hemisphere; in women, with the selective functions of both hemispheres. Figurative thinking in men was less related to hemispheric characteristics of attention compared to women. An increase in figurative originality in women was accompanied by the acceleration of information selection in the right hemisphere and a higher efficiency of local attention and speeds of global processing in the left hemisphere.     

Effects of peptide factors from right and left brain hemispheres of rats on amplitude-time characteristics of projective and interhemispheric evoked responses

Peptide extracts of the right and left hemispheres were applied to the projective (somatosensory and visual) and temporal associative regions of the left brain hemisphere in cats. In the zones of peptide application, evoked potentials (EP) in response to singular and coupled somatic, visual and transcallosal stimuli were registered. The data obtained showed that right and left peptide extracts had different effects on evoked potentials of the left hemisphere. Thus ipsilateral extract increased the amplitude of projective EP, decreased duration of their cycles and amplitude of transcallosal responses. Contralateral extract, on the contrary, activated interhemispheric inputs to brain cortex, suppressed thalamic inputs and increased multimodal properties of neurons. A differential approach to the problem of specific correction of pathological states of the right and left brain hemispheres is required. Right and left peptide extracts may be used in normalization of interhemispheric activity balance in compensatory-recovering processes.     

Interhemispheric Interaction during Memorization of Movement Rhythm

After memorizing a simple periodical movement in the ankle joint, 36 healthy subjects (right-handers) reproduced it from memory. The movement rhythm image that formed during movement in the left ankle joint was memorized better than when the movement was performed by the right extremity. The specific features of interhemispheric interaction at various stages of trace processes, unequal participation of the hemispheres in perception and processing of information, and the physiological expedience of the signal transmission from the right to the left hemisphere are sufficient to assume a basic sequence of hemispheric functional activity redistribution when the brain masters new cognitive actions.     

Localization of cortical lesions of the human brain and features of recognition of emotional expression

The quantity of correct and erroneous identifications of human emotions was compared according to their intonational and mimical cues in the group of healthy persons (31 persons) and in the group of patients with lesions of different cortical parts of the left and right cerebral hemispheres (54 patients). It was established that the intactness of the temporal parts of both hemispheres is important for non-verbal recognition (choosing of appropriate photograph by the observer) of emotions by mimics. Correct verbal identification of emotions by mimics requires the integrity of the fronto-parietal parts of the left hemisphere while verbal identification of emotional intonation needs the intactness of the fronto-parietal parts of the right hemisphere. The significance of the temporal areas (especially of the right hemisphere) increases in case when the emotional colouring of the presented verbal communication does not coincide with its contents.     

Metaphorical and Associative Thinking in Healthy Children and in Children with Asperger's Syndrome at Different Ages

The study of healthy children and patients with childhood autism (Asperger's syndrome) showed that metaphorical thinking is normally efficient at the age of 7–8 years and that autistic children have an impaired ability to understand metaphors and idioms widely used in verbal communication. The deficit of metaphorical thinking in autism is thought to be due to a decreased activity of the right hemisphere. In a study of associative thinking, healthy schoolchildren displayed a high degree of association between words describing sensual objects and autistic patients displayed an impairment of objective associations and a predominance of proper names, which is indicative of the left-hemispheric type of association. The impairment of the speech and mental activity (metaphorical and associative thinking) testified to changes in the interhemispheric interaction in autistic children, which is likely to show up in a decreased functional activity of the right hemisphere and an increased activity of the left hemisphere.     

Interhemispheric asymmetry of positive emotional reactions in rats

Interhemispheric asymmetry of positive emotional reactions was studied in rats: satisfaction of drinking need and self-stimulation. Successive inactivation of the hemispheres was carried out by potassium spreading depression. Switching off of the right as well as the left hemispheres symmetrically influenced the whole quantity of the water, drunk by the rats to a full thirst satisfaction, i. e. the magnitude of need. However, at different stages of drinking need satisfaction an interhemispheric asymmetry was observed: under a strong drinking motivation the right hemisphere dominated, under a weak motivation--the left one. Switching off of the right hemisphere lowered the frequency of self-stimulation of the lateral hypothalamus and switching off the left one heightened it, testifying to the dominance of the right hemisphere in the reaction of self-stimulation. This reaction was also characterized by asymmetry of the lateral hypothalamus nuclei; reactivity to hemispheres inactivation (decreasing or increasing of self-stimulation frequency) of the right nucleus was more expressed than that of the left one.     

Characteristics of the interhemispheric EEG relationships in assessing the functional state of the human brain

In healthy subjects (11 right-handed men) reorganization was studied of intra- and interhemispheric correlation of the electrical brain activity at transition from the state of alertness to drowsiness. At the lowering of alertness level, the coherence of hemispheres symmetrical points changed not abruptly, with a tendency towards an increase at differently directed character of changes of combinations of separate physiological rhythms ranges. Comparison of the EEG coherence changes within the right and left hemispheres revealed a greater reactivity of the left (dominant) hemisphere. The reduction of the predominance (observed in the dominant hemisphere in alertness) of the degree of EEG conjunction, at transition to drowsiness, leads to smoothing of interhemispheric asymmetry in the organization of electrical brain processes.     

Functional asymmetry of the neocortex electrical activity during food conditioning in dogs

Four dogs were trained to perform a conditioned alimentary response to a sound stimulus. The EEG was recorded from six pairs of chronically implanted neocortical electrodes. The EEG spectra and coherence functions between the neighboring derivations of each of the hemispheres were analyzed in the theta, alpha, beta 1 and beta 2 frequency ranges. At the first stages of conditioning, the percent of cases increased when the highest mean values of EEG frequency were localized in the left hemisphere. Later on the percent of cases, when the mean coherence values in the left hemisphere were higher than in the right hemisphere, also increased. At the stage of conditioned response stabilization, this asymmetry either disappeared or the right hemisphere became more active than the left one. The spatial localization of the maximal values of the EEG frequency was different for different frequency ranges. The highest values in the beta 1 range were more frequently registered in the posterior cortical regions and in the beta 2 range they were revealed, predominantly, in the anterior areas. The maximal values of coherence dominated in the anterior regions and their spatial distribution was similar for different frequencies. Thus, the initial stages of conditioning are accompanied by activation of the left hemisphere.