M. G. Starchenko

Study of the Brain Organization of Creativity: III. Brain Activation Assessed by the Local Cerebral Blood Flow and EEG

In this article, a polymethodological approach was applied to the analysis of the brain organization of creative thinking. The electroencephalographic studies and the investigation of the local cerebral blood flow by means of positron-emission tomography in the same testing conditions substantially validate and supplement each other. The physiological indices of subjects were recorded during the composition of stories with the given words belonging to the same or different semantic fields. The reconstruction of correct grammatical forms in a presented text and memorizing of a set of words were used as control tasks. The fundamental importance of the processes taking place in both frontal lobes (Brodmanns areas (BA) 8–11 and 44–47) and the interhemispheric interaction was demonstrated.

EEG local and spatial synchronization during a test on the in site strategy of solving creative verbal tasks

In earlier studies of brain mechanisms of creative activity that were performed at the Institute of the Human Brain, Russian Academy of Sciences, it was found that, during composition of a story including words from different semantic fields, subjects used either a strategy of “uniform” work on the text (a successive, noninsight strategy) or a strategy of deferred, “impulsive” generation of a story immediately before or even during a report (an insight strategy) [1]. At the previous stage, we examined subjects using only the noninsight strategy [2, 3]. In this communication, we present the results of EEG analysis of subjects during their performance of a task requiring the insight strategy. The subjects were presented with two kinds of tasks: (1) in the test task, task D (a variation of Mednick’s remote association test), a subject had to link a “difficult” sequence of 12 words from different semantic fields with associated words (nouns); (2) in the control task, task E (a variation of the generalization test applied in clinical psychology), a subject had to choose five concrete examples (objects or phenomena) belonging to a given word category in response to words of these categories presented in random order (“easy” sequences). Two groups of subjects participated in the study. The first group (15 subjects) comprised first-year students of the Faculty of Acting of the State Academy of Dramatic Art (9 men and 6 women). The second group (15 subjects) comprised students of different St. Petersburg higher educational institutions (7 men and 8 women). The subjects performed each task in silence within a period of 10 s after its administration. The EEG was recorded over the course of this period. They then gave an oral report after a signal. The monopolar EEG was recorded in 19 standard derivations (10/20 system) in reference to linked earlobe electrodes in the frequency band 1.5–30 Hz with a sampling rate of 125 Hz. During the task performance, ten 1-s EEG segments were recorded. The records were analyzed visually, and EEG segments with visible artifacts were excluded from the subsequent analysis. The EEG quantitative characteristics were calculated by means of the WinEEG software package, developed by V.A. Ponomarev. In this communication, we deal with estimations of the EEG absolute spectral power and coherence function (characteristics of the local and spatial EEG synchronization, respectively), summed in the following frequency bands: ∆ (1.5–3.5 Hz), θ (4–7 Hz), α 1 (7.5–9.5 Hz), α 2 (10–12.5 Hz), β 1 (13–18 Hz), and β 2 (18.5–30 Hz). Arrays of the estimations, averaged for each subject during performance of each task, were normalized using the transforms Y =

Selective attention to human voice enhances brain activity bilaterally in the superior temporal sulcus.

Regional cerebral blood flow was measured with positron emission tomography (PET) in 10 healthy male volunteers. They heard two binaurally delivered concurrent stories, one spoken by a male voice and the other by a female voice. A third story was presented at the same time as a text running on a screen. The subjects were instructed to attend silently to one of the stories at a time. In an additional resting condition, no stories were delivered. PET data showed that in comparison with the reading condition, the brain activity in the speech-listening conditions was enhanced bilaterally in the anterior superior temporal sulcus including cortical areas that have been reported to be specifically sensitive to human voice. Previous studies on attention to non-linguistic sounds and visual objects, in turn, showed prefrontal activations that are presumably related to attentional control functions. However, comparisons of the present speech-listening and reading conditions with each other or with the resting condition indicated no prefrontal activity, except for an activation in the inferior frontal cortex that was presumably associated with semantic and syntactic processing of the attended story. Thus, speech listening, as well as reading, even in a distracting environment appears to depend less on the prefrontal control functions than do other types of attention-demanding tasks, probably because selective attention to speech and written text are over-learned actions rehearsed daily.

Study of the Brain Organization of Creative Thinking

This article is a continuation of a series of works on the brain organization of creative thinking. It was shown in earlier studies that, when solving creative tasks, subjects choose between two strategies (successive and insight), and the results of the study of the brain mechanisms of the successive strategy were described [1–3]. The results of positron-emission tomography (PET) study of the second (insight) strategy of solving creative tasks are presented in this communication.

Comparison of the effects of the subjective complexity and verbal creativity on EEG spectral power parameters

The EEG recording was made when the subjects performed tasks that involved overcoming the stereotype (creative) and retrieving information from memory (noncreative) with the usual and complicated presentation of the initial material (incomplete proverbs and sayings without concluding words). The subjective complexity of the task performance under different conditions was assessed. The EEG power from 19 EEG derivations was compared in the β2 and γ frequency bands. The creative task performance was associated with a marked increase in the EEG power; significantly more complicated noncreative tasks were not accompanied by marked changes in the EEG power in these bands.

Stages of the cerebral mechanisms of deceptive responses

Cerebral mechanisms of perceiving and telling lies were studied by recording event-related potentials (ERPs) both after an actual deceptive response and during the time interval when the subject decided to tell a lie. Ten healthy volunteers participated in the study. The test consisted of their playing a game against a computer. The subjects could choose between deceptive and truthful answers so as to win the game. The subjects gave a deceptive answer intentionally, the structure of the test ensuring equal numbers of deceptive and truthful answers. The relaxation times in the cases of truthful and deceptive answers did not differ significantly from each other. The comparison of ERPs accompanying deceptive and truthful answers showed the existence of a negativity with a latent period of 90 ms in the regions of the right frontal, central, and right parietal derivations. This negativity indicated that the brain reacted to a deceptive answer even if this a priori “erroneous” act ensured reaching the goal and, in this sense, was subjectively relevant. In terms of the cerebral error detector mechanism, this phenomenon may be regarded as a special case of a general response of the brain to giving an incorrect (deceptive) answer, rather than a response to a lie per se. The interval of time when, presumably, the decision on a deceptive answer was being made was found to contain the late positive component P540, which is most likely to be involved in the preparation of the deceptive answer and the intention to tell a lie.

Changes in the power and coherence spectra of the EEG rhythmic components during solution of a verbal creative task of overcoming a stereotype

Changes in EEG power and coherence were analyzed in 117 subjects during the performance of the creative task of finishing well-known proverbs in a new way, so as to change, if possible, their meaning, and the noncreative task of recalling the original (well-known) version of the end of each proverb. A characteristic feature of the creative task was that proverbs and sayings are stereotypes fixed in a memory matrix. During the task performance, the EEG was recorded in 19 derivations according to the international 10–20 system. Performance of the creative task was accompanied by a highly significant and reproducible increase in the power of the γ and β2 EEG frequency bands, as well as a less pronounced decrease in the power of the ϑ band in the central and parietoccipital cortical areas. In addition, the performance of the creative task was also characterized by an increase in the EEG coherence in the α2, β2, and γ bands. No gender-related differences were found in the patterns of EEG changes.

EEG Reflection of Clinical Effects Dynamics during Botulinum Toxin Therapy of Movement Disorders under Long-Term Consciousness Disorders

When studying the dynamics of brain electric activity (BEA) in the course of botulinum toxin (Incobotulinumtoxin A) injections into all hypertonic muscles of 16 patients suffering from post-coma longterm consciousness disorders, BEA changes were observed to start within the first minutes after the first intramuscular injection of botulinum toxin, while not being associated with any pain stimulus response. Despite the diversity of brain lesions in these patients, the dynamics of BEA reorganisation during botulinum toxin therapy showed the presence of pathological sensorimotor integration involving the whole brain in case of long-term consciousness disorders. In our opinion, it is expressed in a pathological state developing in the brain, which affects the polyfunctional capabilities of neurons. This state is unbalanced due to destabilizing effect at the beginning of the reduction by pathological hyperafferentation from muscles and, in principle, can be disrupted at a complete reduction. It is, however, maintained by memory matrix, which manifests itself in the shape of oscillation process during its disruption when the newly build-up BEA is occasionally displaced by the previous one. During the reduction of sensory hyperafferentation, BEA reorganisation initially involved the motor cortex (in 15 out of 16 patients) and then spread to other brain areas, including those responsible for the higher mental functions, vision, and hearing. The first transiently decreased muscle tone (in all patients) and improvement of neurological signs of awareness (in some patients) were observed immediately after injecting all hypertonic muscles with widespread BEA changes. The appearance of high-frequency EEG activity in the frontal areas was considered as a universal marker of an improved functional state of the brain during the disruption of pathological sensorimotor integration even before clinical signs, suggesting neuronal readiness to maintain various activities. In view of data obtained, the first-stage clinical measures in patients with disorders of consciousness should focus on disrupting pathological sensorimotor integration, opening a way for restoring neuronal functional activity, provided that all “pathological afferents” are reduced.

On the possibility of the correction of emotional disorders under the conditions of the action of a destabilizing factor

The influence of the drug dilantin on the mental state of humans in the presence of objective neuroticizing factors (restriction of freedom and the concomitants) was studied. A positive effect of the drug on the emotional state of prisoners, namely, decreases in the levels of reactive and personal anxiety and depression, as well as in the probability of the development of neurotic disorders, was shown.