Alexander Korotkov | Russian academy of sciences (original) (raw)
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Papers by Alexander Korotkov
Functional connectivity between brain areas involved in the processing of complex language forms ... more Functional connectivity between brain areas involved in the processing of complex language forms remains largely unexplored. Contributing to the debate about neural mechanisms underlying regular and irregular inflectional morphology processing in the mental lexicon, we conducted an fMRI experiment in which participants generated forms from different types of Russian verbs and nouns as well as from nonce stimuli.The data were subjected to a whole brain voxel-wise analysis of context dependent changes in functional connectivity [the so-called psychophysiological interaction (PPI) analysis]. Unlike previously reported subtractive results that reveal functional segregation between brain areas, PPI provides complementary information showing how these areas are functionally integrated in a particular task. To date, PPI evidence on inflectional morphology has been scarce and only available for inflectionally impoverished English verbs in a same-different judgment task. Using PPI here in conjunction with a production task in an inflectionally rich language, we found that functional connectivity between the left inferior frontal gyrus (LIFG) and bilateral superior temporal gyri (STG) was significantly greater for regular real verbs than for irregular ones. Furthermore, we observed a significant positive covariance between the number of mistakes in irregular real verb trials and the increase in functional connectivity between the LIFG and the right anterior cingulate cortex in these trails, as compared to regular ones. Our results therefore allow for dissociation between regularity and processing difficulty effects. These results, on the one hand, shed new light on the functional interplay within the LIFG-bilateral STG language-related network and, on the other hand, call for partial reconsideration of some of the previous findings while stressing the role of functional temporo-frontal connectivity in complex morphological processes.
Human Physiology, 2012
ABSTRACT The goal of the study was analysis of the cerebral mechanisms of deliberate deception. T... more ABSTRACT The goal of the study was analysis of the cerebral mechanisms of deliberate deception. The eventrelated functional magnetic resonance (ER fMRI) imaging technique was used to assess the changes in the functional brain activity by means of recording the blood oxygen level-dependent (BOLD) signal. Twelve right-handed healthy volunteers aged 19–44 years participated in the study. The BOLD images were obtained during three experimental trials: deliberate deception, manipulative honest and control truthful trials (catch trials). The deliberate deception and manipulative honest actions were characterized by a BOLD signal increase in the anterior cingulate (Brodmann’s area (BA) 32), frontal (BAs 9/10, 6), and parietal (BA 40) cortices as compared with a truthful response. Comparison of the ER fMRI data with the results of earlier studies where event-related potentials (ERPs) were recorded under similar conditions indicates the involvement of the brain mechanism of error detection in deliberate deception.
В обзоре сформулированы и аргументированы теоретические положения о патогенетической роли пре- и ... more В обзоре сформулированы и аргументированы теоретические положения о патогенетической роли пре- и перинатального гипоксически-ишемического поражения мозга в формировании устойчивого кислород-зависимого энергодефицита, составляющего в последующие периоды онтогенеза нейробиологические основы: а) снижения уровня здоровья и компенсаторно-приспособительных возможностей организма; б) нарушений психо-речевого развития и адаптивного поведения у детей; в) раннего развития нервно-психических заболеваний; г) присоединение других видов нарушений энергетического метаболизма мозга (в том числе метаболизма глюкозы) при хронических заболеваниях разной этиологии у лиц молодого и среднего возраста. Выделены и теоретически обоснованы интегральные физиологические параметры типов кислород-зависимого энергодефицита. Исследованы особенности нарушения нейрорефлекторных и нейрогуморальных механизмов регуляции уровня бодрствования, его вегетативного и гемодинамического обеспечения при разных типах энергодефиц...
![Research paper thumbnail of [Factor analysis of brain structure reorganization in patient with multiple sclerosis (based on pet data)]](https://attachments.academia-assets.com/49427991/thumbnails/1.jpg)
](Fiziologiia cheloveka
The goal of present study was to investigate the functional reorganization of brain structures in... more The goal of present study was to investigate the functional reorganization of brain structures in patients with multiple sclerosis (MS). The patterns of distribution of relative estimations of local cerebral metabolic rate of glucose (ICMRglu) in regions of interest (ROIs), corresponding to anatomo-functional brain areas are obtained in groups of healthy volunteers (n=31 subjects) and patients with relapsing-remitting and progressive types of MS (n=59 and 39 accordingly). The analysis of factor structure of the obtained patterns allowed to make a conclusion about the existence of a common features with the factor structure of the distribution of another functional parameter--a regional cerebral blood flow (rCBF). This indicates that both factor solutions mainly reflect the functional organization of a brain. The differences revealed in factor structures of ICMRglu distribution in groups of patients with various types of MS and healthy volunteers allowed to assume that even at early ...
Human Physiology
The goal of the present study was to investigate functional interactions between brain structures... more The goal of the present study was to investigate functional interactions between brain structures during deliberate deception. On the basis of the results obtained and literature data, the following hypothesis has been formulated: the functional interaction between the brain areas responsible for executive control of the behavior localized in the prefrontal cortex (inferior frontal gyrus) and elements of the error detection system of the brain underlie deliberate deception. This hypothesis has been tested using psychophysiological interaction (PPI) analysis, which has revealed that deceptive actions (in comparison to truthful ones) are related to an increased functional connectivity between the left caudate nucleus and left inferior frontal gyrus. The experimental data support our hypothesis that the interaction of the brain systems responsible for executive control and error detection underpins the brain maintenance of execution of deceptive actions.
Voprosy neĭrokhirurgii
Positron emission tomography by using H2(15)O whose distribution in the brain reflects a genuine ... more Positron emission tomography by using H2(15)O whose distribution in the brain reflects a genuine cerebral blood flow was made in 5 patients with suspected intracranial hematomas. It was shown that tunicary hematomas might be diagnosed by positron emission tomography. However, examination of cerebral blood flow was not optimal in this abnormality. Computerized tomography remains the basic method for diagnosing intracranial hematomas and positron emission tomography should be used to evaluate cerebral function.
International Journal of Psychophysiology, 2014
Rossiĭskii fiziologicheskiĭ zhurnal imeni I.M. Sechenova / Rossiĭskaia akademiia nauk, 2013
For many years the modern methods of functional tomographic brain imaging (fMRI and PET) were act... more For many years the modern methods of functional tomographic brain imaging (fMRI and PET) were actively used not only for the research of basic brain functions, but also in clinical practice. In present paper we described the basic characteristics of the signal registered with fMRI and PET, the principles of image reconstruction, as well as the methodological requirements, which are necessary to obtain reliable results. The advantages and limitations of modem tomographic methods of the brain functions investigation are discussed. The need of the complex approach use in brain study is emphasized and methods for the study of functional integration of the brain are suggested.
![Research paper thumbnail of [The characteristics of the functional state of the human brain anatomical formations during different levels of reactive anxiety. A PET study of healthy volunteers]](https://attachments.academia-assets.com/49427123/thumbnails/1.jpg)
](Zhurnal voprosy neĭrokhirurgii imeni N. N. Burdenko
PET data were compared with the results of computerized tomography (CT) and the neurological stat... more PET data were compared with the results of computerized tomography (CT) and the neurological status of patients. The areas of decreased local cerebral blood flow (LCBF) and reduced local cerebral metabolic glucose rates exceeded those of brain injury shown by CT predominantly in patients with brain posttraumatic cysts. In a group of patients with posttraumatic atrophy documented by CT, PET demonstrated cortical and/or subcortical lesions in most cases, providing objective evidence for neurological symptoms. PET is a useful technique to demonstrate regional brain dysfunction in the presence of morphological integrity as assessed by CT.
Neuroscience and Behavioral Physiology, 2013
ABSTRACT The present study addresses the cerebral support for the mechanism of error detection (E... more ABSTRACT The present study addresses the cerebral support for the mechanism of error detection (ED) operating during conscious execution of incorrect actions (deceptions) and in the resting state. Local cerebral blood flow was measured by positron emission tomography (PET), and demonstrated involvement of the anterior cingulate gyrus in processes associated with conscious deception. The data obtained here showed that ED operates in persistently executed errors – conscious control of ED was shown to be impossible. The hypothesis that failure of ED is an important factor in the formation of obsessive-compulsive disorder (OCD) was supported by analysis of PET data on the rate of glucose metabolism in the state of operative rest. Normative data from healthy subjects were compared with results obtained from patients with diagnoses of OCD and Tourette’s syndrome. Patients showed decreases in glucose metabolism in the anterior cingulate gyrus, which can be regarded as a reflection of abnormal functioning of the cerebral ED system.
International Journal of Psychophysiology, 2004
... The previous authors noted the role of BA 40 in switching from one task to another ( Sohn et ... more ... The previous authors noted the role of BA 40 in switching from one task to another ( Sohn et al., 2000), in imagination ( Knauff ... Therefore we speculate that differences in spatial localization of these activations are related to differences in strategies of creative thinking. ...
Human Physiology, 2013
In the present article the features of the functional activity of the anterior cingulate cortex (... more In the present article the features of the functional activity of the anterior cingulate cortex (ACC), a key element of neuroanatomical brain system of an error detection, in drug-resistant forms of obsessive-compulsive disorder (OCD) are discussed on a basis of both original and literature data. Available data indicate the presence of functional deficit in the ACC during OCD. This allows to suggest that functions of the ACC in OCD patient are partially redistributed between other brain areas. Thus in contrast to the previously accepted notion, the ACC as the target ofstereotactic surgery for OCD is pathologically altered brain region. Probably this is the reason why stereotactic destruction of ACC does not lead to significant changes in the patient's psyche. The essence of the pathological reorganisation of the functional activity of the brain in OCD remains unclear and requires further investigation.
Human Physiology, 2010
ABSTRACT The results of comprehensive monitoring of the state of 25 patients in the vegetative st... more ABSTRACT The results of comprehensive monitoring of the state of 25 patients in the vegetative state (prolonged coma) before and after compensating for the factors of secondary brain damage were analyzed and followed up for no less than six months. The primary results showed that the best recovery of consciousness and cognitive functions was observed if, according to the positron emission tomography data, a diffuse decrease in the glucose metabolism rate (GMRglu), significantly exceeding the extent of the zones of morphological/anatomical lesions, was present in the brain before treatment, while the minimal improvement was observed if the GMRglu was sufficiently intact. These and other paradoxical results can be explained if the vegetative state is regarded as a stable pathological state of the brain, which offers new approaches to the treatment of this group of patients.
Human Physiology
The goal of the present study was to investigate functional interactions between brain structures... more The goal of the present study was to investigate functional interactions between brain structures during deliberate deception. On the basis of the results obtained and literature data, the following hypothesis has been formulated: the functional interaction between the brain areas responsible for executive control of the behavior localized in the prefrontal cortex (inferior frontal gyrus) and elements of the error detection system of the brain underlie deliberate deception. This hypothesis has been tested using psychophysiological interaction (PPI) analysis, which has revealed that deceptive actions (in comparison to truthful ones) are related to an increased functional connectivity between the left caudate nucleus and left inferior frontal gyrus. The experimental data support our hypothesis that the interaction of the brain systems responsible for executive control and error detection underpins the brain maintenance of execution of deceptive actions.
International Journal of Psychophysiology, 2014
Functional connectivity between brain areas involved in the processing of complex language forms ... more Functional connectivity between brain areas involved in the processing of complex language forms remains largely unexplored. Contributing to the debate about neural mechanisms underlying regular and irregular inflectional morphology processing in the mental lexicon, we conducted an fMRI experiment in which participants generated forms from different types of Russian verbs and nouns as well as from nonce stimuli.The data were subjected to a whole brain voxel-wise analysis of context dependent changes in functional connectivity [the so-called psychophysiological interaction (PPI) analysis]. Unlike previously reported subtractive results that reveal functional segregation between brain areas, PPI provides complementary information showing how these areas are functionally integrated in a particular task. To date, PPI evidence on inflectional morphology has been scarce and only available for inflectionally impoverished English verbs in a same-different judgment task. Using PPI here in conjunction with a production task in an inflectionally rich language, we found that functional connectivity between the left inferior frontal gyrus (LIFG) and bilateral superior temporal gyri (STG) was significantly greater for regular real verbs than for irregular ones. Furthermore, we observed a significant positive covariance between the number of mistakes in irregular real verb trials and the increase in functional connectivity between the LIFG and the right anterior cingulate cortex in these trails, as compared to regular ones. Our results therefore allow for dissociation between regularity and processing difficulty effects. These results, on the one hand, shed new light on the functional interplay within the LIFG-bilateral STG language-related network and, on the other hand, call for partial reconsideration of some of the previous findings while stressing the role of functional temporo-frontal connectivity in complex morphological processes.
Human Physiology, 2012
ABSTRACT The goal of the study was analysis of the cerebral mechanisms of deliberate deception. T... more ABSTRACT The goal of the study was analysis of the cerebral mechanisms of deliberate deception. The eventrelated functional magnetic resonance (ER fMRI) imaging technique was used to assess the changes in the functional brain activity by means of recording the blood oxygen level-dependent (BOLD) signal. Twelve right-handed healthy volunteers aged 19–44 years participated in the study. The BOLD images were obtained during three experimental trials: deliberate deception, manipulative honest and control truthful trials (catch trials). The deliberate deception and manipulative honest actions were characterized by a BOLD signal increase in the anterior cingulate (Brodmann’s area (BA) 32), frontal (BAs 9/10, 6), and parietal (BA 40) cortices as compared with a truthful response. Comparison of the ER fMRI data with the results of earlier studies where event-related potentials (ERPs) were recorded under similar conditions indicates the involvement of the brain mechanism of error detection in deliberate deception.
В обзоре сформулированы и аргументированы теоретические положения о патогенетической роли пре- и ... more В обзоре сформулированы и аргументированы теоретические положения о патогенетической роли пре- и перинатального гипоксически-ишемического поражения мозга в формировании устойчивого кислород-зависимого энергодефицита, составляющего в последующие периоды онтогенеза нейробиологические основы: а) снижения уровня здоровья и компенсаторно-приспособительных возможностей организма; б) нарушений психо-речевого развития и адаптивного поведения у детей; в) раннего развития нервно-психических заболеваний; г) присоединение других видов нарушений энергетического метаболизма мозга (в том числе метаболизма глюкозы) при хронических заболеваниях разной этиологии у лиц молодого и среднего возраста. Выделены и теоретически обоснованы интегральные физиологические параметры типов кислород-зависимого энергодефицита. Исследованы особенности нарушения нейрорефлекторных и нейрогуморальных механизмов регуляции уровня бодрствования, его вегетативного и гемодинамического обеспечения при разных типах энергодефиц...
Fiziologiia cheloveka
The goal of present study was to investigate the functional reorganization of brain structures in... more The goal of present study was to investigate the functional reorganization of brain structures in patients with multiple sclerosis (MS). The patterns of distribution of relative estimations of local cerebral metabolic rate of glucose (ICMRglu) in regions of interest (ROIs), corresponding to anatomo-functional brain areas are obtained in groups of healthy volunteers (n=31 subjects) and patients with relapsing-remitting and progressive types of MS (n=59 and 39 accordingly). The analysis of factor structure of the obtained patterns allowed to make a conclusion about the existence of a common features with the factor structure of the distribution of another functional parameter--a regional cerebral blood flow (rCBF). This indicates that both factor solutions mainly reflect the functional organization of a brain. The differences revealed in factor structures of ICMRglu distribution in groups of patients with various types of MS and healthy volunteers allowed to assume that even at early ...
Human Physiology
The goal of the present study was to investigate functional interactions between brain structures... more The goal of the present study was to investigate functional interactions between brain structures during deliberate deception. On the basis of the results obtained and literature data, the following hypothesis has been formulated: the functional interaction between the brain areas responsible for executive control of the behavior localized in the prefrontal cortex (inferior frontal gyrus) and elements of the error detection system of the brain underlie deliberate deception. This hypothesis has been tested using psychophysiological interaction (PPI) analysis, which has revealed that deceptive actions (in comparison to truthful ones) are related to an increased functional connectivity between the left caudate nucleus and left inferior frontal gyrus. The experimental data support our hypothesis that the interaction of the brain systems responsible for executive control and error detection underpins the brain maintenance of execution of deceptive actions.
Voprosy neĭrokhirurgii
Positron emission tomography by using H2(15)O whose distribution in the brain reflects a genuine ... more Positron emission tomography by using H2(15)O whose distribution in the brain reflects a genuine cerebral blood flow was made in 5 patients with suspected intracranial hematomas. It was shown that tunicary hematomas might be diagnosed by positron emission tomography. However, examination of cerebral blood flow was not optimal in this abnormality. Computerized tomography remains the basic method for diagnosing intracranial hematomas and positron emission tomography should be used to evaluate cerebral function.
International Journal of Psychophysiology, 2014
Rossiĭskii fiziologicheskiĭ zhurnal imeni I.M. Sechenova / Rossiĭskaia akademiia nauk, 2013
For many years the modern methods of functional tomographic brain imaging (fMRI and PET) were act... more For many years the modern methods of functional tomographic brain imaging (fMRI and PET) were actively used not only for the research of basic brain functions, but also in clinical practice. In present paper we described the basic characteristics of the signal registered with fMRI and PET, the principles of image reconstruction, as well as the methodological requirements, which are necessary to obtain reliable results. The advantages and limitations of modem tomographic methods of the brain functions investigation are discussed. The need of the complex approach use in brain study is emphasized and methods for the study of functional integration of the brain are suggested.
Zhurnal voprosy neĭrokhirurgii imeni N. N. Burdenko
PET data were compared with the results of computerized tomography (CT) and the neurological stat... more PET data were compared with the results of computerized tomography (CT) and the neurological status of patients. The areas of decreased local cerebral blood flow (LCBF) and reduced local cerebral metabolic glucose rates exceeded those of brain injury shown by CT predominantly in patients with brain posttraumatic cysts. In a group of patients with posttraumatic atrophy documented by CT, PET demonstrated cortical and/or subcortical lesions in most cases, providing objective evidence for neurological symptoms. PET is a useful technique to demonstrate regional brain dysfunction in the presence of morphological integrity as assessed by CT.
Neuroscience and Behavioral Physiology, 2013
ABSTRACT The present study addresses the cerebral support for the mechanism of error detection (E... more ABSTRACT The present study addresses the cerebral support for the mechanism of error detection (ED) operating during conscious execution of incorrect actions (deceptions) and in the resting state. Local cerebral blood flow was measured by positron emission tomography (PET), and demonstrated involvement of the anterior cingulate gyrus in processes associated with conscious deception. The data obtained here showed that ED operates in persistently executed errors – conscious control of ED was shown to be impossible. The hypothesis that failure of ED is an important factor in the formation of obsessive-compulsive disorder (OCD) was supported by analysis of PET data on the rate of glucose metabolism in the state of operative rest. Normative data from healthy subjects were compared with results obtained from patients with diagnoses of OCD and Tourette’s syndrome. Patients showed decreases in glucose metabolism in the anterior cingulate gyrus, which can be regarded as a reflection of abnormal functioning of the cerebral ED system.
International Journal of Psychophysiology, 2004
... The previous authors noted the role of BA 40 in switching from one task to another ( Sohn et ... more ... The previous authors noted the role of BA 40 in switching from one task to another ( Sohn et al., 2000), in imagination ( Knauff ... Therefore we speculate that differences in spatial localization of these activations are related to differences in strategies of creative thinking. ...
Human Physiology, 2013
In the present article the features of the functional activity of the anterior cingulate cortex (... more In the present article the features of the functional activity of the anterior cingulate cortex (ACC), a key element of neuroanatomical brain system of an error detection, in drug-resistant forms of obsessive-compulsive disorder (OCD) are discussed on a basis of both original and literature data. Available data indicate the presence of functional deficit in the ACC during OCD. This allows to suggest that functions of the ACC in OCD patient are partially redistributed between other brain areas. Thus in contrast to the previously accepted notion, the ACC as the target ofstereotactic surgery for OCD is pathologically altered brain region. Probably this is the reason why stereotactic destruction of ACC does not lead to significant changes in the patient's psyche. The essence of the pathological reorganisation of the functional activity of the brain in OCD remains unclear and requires further investigation.
Human Physiology, 2010
ABSTRACT The results of comprehensive monitoring of the state of 25 patients in the vegetative st... more ABSTRACT The results of comprehensive monitoring of the state of 25 patients in the vegetative state (prolonged coma) before and after compensating for the factors of secondary brain damage were analyzed and followed up for no less than six months. The primary results showed that the best recovery of consciousness and cognitive functions was observed if, according to the positron emission tomography data, a diffuse decrease in the glucose metabolism rate (GMRglu), significantly exceeding the extent of the zones of morphological/anatomical lesions, was present in the brain before treatment, while the minimal improvement was observed if the GMRglu was sufficiently intact. These and other paradoxical results can be explained if the vegetative state is regarded as a stable pathological state of the brain, which offers new approaches to the treatment of this group of patients.
Human Physiology
The goal of the present study was to investigate functional interactions between brain structures... more The goal of the present study was to investigate functional interactions between brain structures during deliberate deception. On the basis of the results obtained and literature data, the following hypothesis has been formulated: the functional interaction between the brain areas responsible for executive control of the behavior localized in the prefrontal cortex (inferior frontal gyrus) and elements of the error detection system of the brain underlie deliberate deception. This hypothesis has been tested using psychophysiological interaction (PPI) analysis, which has revealed that deceptive actions (in comparison to truthful ones) are related to an increased functional connectivity between the left caudate nucleus and left inferior frontal gyrus. The experimental data support our hypothesis that the interaction of the brain systems responsible for executive control and error detection underpins the brain maintenance of execution of deceptive actions.
International Journal of Psychophysiology, 2014