Shestakova A.,Moscow State University of Psychology and Education |
Rieskamp J.,University of Basel |
Tugin S.,Saint Petersburg State University |
Ossadtchi A.,Saint Petersburg State University |
And 2 more authors.
Social Cognitive and Affective Neuroscience | Year: 2013
Humans often change their beliefs or behavior due to the behavior or opinions of others. This study explored, with the use of human event-related potentials (ERPs), whether social conformity is based on a general performance-monitoring mechanism. We tested the hypothesis that conflicts with a normative group opinion evoke a feedback-related negativity (FRN) often associated with performance monitoring and subsequent adjustment of behavior. The experimental results show that individual judgments of facial attractiveness were adjusted in line with a normative group opinion. A mismatch between individual and group opinions triggered a frontocentral negative deflection with the maximum at 200 ms, similar to FRN. Overall, a conflict with a normative group opinion triggered a cascade of neuronal responses: from an earlier FRN response reflecting a conflict with the normative opinion to a later ERP component (peaking at 380 ms) reflecting a conforming behavioral adjustment. These results add to the growing literature on neuronal mechanisms of social influence by disentangling the conflict-monitoring signal in response to the perceived violation of social norms and the neural signal of a conforming behavioral adjustment. © The Author (2012). Published by Oxford University Press.
Vvedensky V.L.,Moscow State University of Psychology and Education |
Prokofyev A.O.,Moscow State University of Psychology and Education
Neural Computation | Year: 2016
We studied magnetic signals from the human brain recorded during a second before a self-paced finger movement. Sharp triangular peaks were observed in the averaged signals about 0.7 second before the finger movement. The amplitude of the peaks varied considerably from trial to trial, which indicated that the peaks were concurrent with much longer oscillatory processes. One can cluster trials into distinct groups with characteristic sequences of events. Prominent short trains of pulses in the beta frequency band were identified in the premovement period. This observation suggests that during preparation of the intended movement, cortical activity is well organized in time but differs from trial to trial. Magnetoencephalography can capture these processes with high temporal resolution and allows their study in fine detail. © 2016 Massachusetts Institute of Technology.
Alkhimov V.I.,Moscow State University of Psychology and Education
Theoretical and Mathematical Physics(Russian Federation) | Year: 2017
We consider an ensemble of particles not interacting with each other and randomly walking in the d-dimensional Euclidean space ℝd. The individual moves of each particle are governed by the same distribution, but after the completion of each such move of a particle, its position in the medium is “marked” as a region in the form of a ball of diameter r0, which is not available for subsequent visits by this particle. As a result, we obtain the corresponding ensemble in ℝd of marked trajectories in each of which the distance between the centers of any pair of these balls is greater than r0. We describe a method for computing the asymptotic form of the probability density Wn(r) of the distance r between the centers of the initial and final balls of a trajectory consisting of n individual moves of a particle of the ensemble. The number n, the trajectory modulus, is a random variable in this model in addition to the distance r. This makes it necessary to determine the distribution of n, for which we use the canonical distribution obtained from the most probable distribution of particles in the ensemble over the moduli of their trajectories. Averaging the density Wn(r) over the canonical distribution of the modulus n allows finding the asymptotic behavior of the probability density of the distance r between the ends of the paths of the canonical ensemble of particles in a self-avoiding random walk in ℝd for 2 ≤ d < 4. © 2017, Pleiades Publishing, Ltd.
Stroganova T.A.,Moscow State University of Psychology and Education |
Orekhova E.V.,Gothenburg University |
Prokofyev A.O.,Moscow State University of Psychology and Education |
Tsetlin M.M.,Moscow State University of Psychology and Education |
And 3 more authors.
Cortex | Year: 2012
Illusory contour (IC) perception, a fruitful model for studying the automatic contextual integration of local image features, can be used to investigate the putative impairment of such integration in children with autism spectrum disorders (ASD). We used the illusory Kanizsa square to test how the phase-locked (PL) gamma and beta electroencephalogram (EEG) responses of typically developing (TD) children aged 3-7 years and those with ASD were modulated by the presence of IC in the image. The PL beta and gamma activity strongly differentiated between IC and control figures in both groups of children (IC effect). However, the timing, topography, and direction of the IC effect differed in TD and ASD children. Between 40. msec and 120. msec after stimulus onset, both groups demonstrated lower power of gamma oscillations at occipital areas in response to IC than in response to the control figure. In TD children, this relative gamma suppression was followed by relatively higher parieto-occipital gamma and beta responses to IC within 120-270. msec after stimulus onset. This second stage of IC processing was absent in children with ASD. Instead, their response to IC was characterized by protracted (40-270. msec) relative reduction of gamma and beta oscillations at occipital areas. We hypothesize that children with ASD rely more heavily on lower-order processing in the primary visual areas and have atypical later stage related to higher-order processes of contour integration. © 2011 Elsevier Srl.
Iourov I.Y.,Russian Academy of Medical Sciences |
Vorsanova S.G.,Moscow State University of Psychology and Education |
Yurov Y.B.,Moscow State University of Psychology and Education
Cytogenetic and Genome Research | Year: 2013
Recent genomic advances have exacerbated the problem of interpreting genome-wide association studies aimed at uncovering genetic basis of brain disorders. Despite of a plethora of data on candidate genes determining the susceptibility to neuropsychiatric diseases, no consensus is reached on their intrinsic contribution to the pathogenesis, and the influence of the environment on these genes is incompletely understood. Alternatively, single-cell analyses of the normal and diseased human brain have shown that somatic genome/epigenome variations (somatic mosaicism) do affect neuronal cell populations and are likely to mediate pathogenic processes associated with brain dysfunctions. Such (epi-)genomic changes are likely to arise from disturbances in genome maintenance and cell cycle regulation pathways as well as from environmental exposures. Therefore, one can suggest that, at least in a proportion of cases, inter- and intragenic variations (copy number variations (CNVs) or single nucleotide polymorphisms (SNPs)) associated with major brain disorders (i.e. schizophrenia, Alzheimer's disease, autism) lead to genetic dysregulation resulting in somatic genetic and epigenetic mosaicism. In addition, environmental influences on malfunctioning cellular machinery could trigger a cascade of abnormal processes producing genomic/chromosomal instability (i.e. brain-specific aneuploidy). Here, a brief analysis of a genome-wide association database has allowed us to support these speculations. Accordingly, an ontogenetic 2-/multiple-hit mechanism of brain diseases was hypothesized. Finally, we speculate that somatic cell genomics approach considering both genome-wide associations and somatic (epi-)genomic variations is likely to have bright perspectives for disease-oriented genome research. Copyright © 2013 S. Karger AG, Basel.
Ivlieva N.Yu.,Moscow State University of Psychology and Education
Neuroscience and Behavioral Physiology | Year: 2011
The midbrain dopaminergic system is traditionally regarded as a "common neural currency" for rewards of any modality. As regards the specific involvement of the mesocorticolimbic system in behavior there are currently three main hypotheses under consideration: 1) dopamine mediates "satisfaction;" 2) dopamine signals errors in predictions of rewards and thus serves as a learning signal critical in processes of associative learning; 3) dopamine creates motivation for actions directed to receiving a reward. However, considerable evidence has been obtained providing different levels of contradiction of these views of the functions of central dopamine. Attempts to clarify the role of the mesocorticolimbic dopaminergic system in adaptive behavior have shown that this system is involved in learning processes, in assessing the results of actions, in the processes identifying the significance of new stimuli, and in the mechanisms of decision-taking, though most studies have provided evidence that that the activity of the mesocorticolimbic system is of particular importance in situations of indeterminacy. We believe that this is the major enigma of dopamine, on the one hand supporting spontaneity and, on the other, protecting against excessive reactivity. © 2011 Springer Science+Business Media, Inc.
Barabanschikov V.A.,Moscow State University of Psychology and Education
Perception | Year: 2015
We studied preferably fixated parts and features of human face in the process of recognition of facial expressions of emotion. Photographs of facial expressions were used. Participants were to categorize these as basic emotions; during this process, eye movements were registered. It was found that variation in the intensity of an expression is mirrored in accuracy of emotion recognition; it was also reflected by several indices of oculomotor function: duration of inspection of certain areas of the face, its upper and bottom or right parts, right and left sides; location, number and duration of fixations, viewing trajectory. In particular, for low-intensity expressions, right side of the face was found to be attended predominantly (right-side dominance); the right-side dominance effect, was, however, absent for expressions of high intensity. For both low- and high-intensity expressions, upper face part was predominantly fixated, though with greater fixation of high-intensity expressions. The majority of trials (70%), in line with findings in previous studies, revealed a V-shaped pattern of inspection trajectory. No relationship, between accuracy of recognition of emotional expressions, was found, though, with either location and duration of fixations or pattern of gaze directedness in the face. © 2015, © The Author(s) 2015.
Orekhova E.V.,Moscow State University of Psychology and Education |
Stroganova T.A.,Moscow State University of Psychology and Education
Frontiers in Human Neuroscience | Year: 2014
The extended phenotype of autism spectrum disorders (ASD) includes a combination of arousal regulation problems, sensory modulation difficulties, and attention re-orienting deficit. A slow and inefficient re-orienting to stimuli that appear outside of the attended sensory stream is thought to be especially detrimental for social functioning. Event-related potentials (ERPs) and magnetic fields (ERFs) may help to reveal which processing stages underlying brain response to unattended but salient sensory event are affected in individuals with ASD. Previous research focusing on two sequential stages of the brain response-automatic detection of physical changes in auditory stream, indexed by mismatch negativity (MMN), and evaluation of stimulus novelty, indexed by P3a component, -found in individuals with ASD either increased, decreased, or normal processing of deviance and novelty. The review examines these apparently conflicting results, notes gaps in previous findings, and suggests a potentially unifying hypothesis relating the dampened responses to unattended sensory events to the deficit in rapid arousal process. Specifically, "sensory gating" studies focused on pre-attentive arousal consistently demonstrated that brain response to unattended and temporally novel sound in ASD is already affected at around 100 ms after stimulus onset. We hypothesize that abnormalities in nicotinic cholinergic arousal pathways, previously reported in individuals with ASD, may contribute to these ERP/ERF aberrations and result in attention re-orienting deficit. Such cholinergic dysfunction may be present in individuals with ASD early in life and can influence both sensory processing and attention re-orienting behavior. Identification of early neurophysiological biomarkers for cholinergic deficit would help to detect infants "at risk" who can potentially benefit from particular types of therapies or interventions. © 2014 Orekhova and Stroganova.
Vvedensky V.L.,Moscow State University of Psychology and Education
Neuroscience Letters | Year: 2014
We measured magnetic cortical responses to self-paced finger movements. Wide frequency band measurements revealed sharp elements of the response wave-shape, and allowed analysis of individual trials. The signal time course was decomposed into three components in the time window from 600. ms before to 600. ms after the movement. Each component had its own wave-shape and highly individual behavior. Two components displayed large trial-to-trial amplitude variations, whereas the amplitude of the third, high-frequency component remained stable. The frequency spectrum of the high-frequency component decayed exponentially, which indicates deterministic dynamics for the processes generating this magnetic signal. In spite of the large variations in the movement-related cortical signals, the movement itself, as measured by accelerometer attached to the finger tip, remained stable from trial to trial. The magnetic measurements are well-suited to reveal fine details of the process of movement initiation. © 2014 Elsevier Ireland Ltd.
Butorina A.,Moscow State University of Psychology and Education |
Prokofyev A.,Moscow State University of Psychology and Education |
Litvak V.,University College London |
Stroganova T.,Moscow State University of Psychology and Education
NeuroImage | Year: 2014
We tested whether mirror visual feedback (MVF) from a moving hand induced high gamma oscillation (HGO) response in the hemisphere contralateral to the mirror and ipsilateral to the self-paced movement. MEG was recorded in 14 subjects under three conditions: bilateral synchronous movements of both index fingers (BILATERAL), movements of the right hand index finger while observing the immobile left index finger (NOMIRROR), and movements of the right hand index finger while observing its mirror reflection (MIRROR). The right hemispheric spatiospectral regions of interests (ROIs) in the sensor space, sensitive to bilateral movements, were found by statistical comparison of the BILATERAL spectral responses to baseline. For these ROIs, the post-movement HGO responses were compared between the MIRROR and NOMIRROR conditions. We found that MVF from the moving hand, similarly to the real movements of the opposite hand, induced HGOs (55-85. Hz) in the sensorimotor cortex. This MVF effect was frequency-specific and did not spread to oscillations in other frequency bands. This is the first study demonstrating movement-related HGO induced by MVF from the moving hand in the absence of proprioceptive feedback signaling. Our findings support the hypothesis that MVF can trigger the feedback-based control processes specifically associated with perception of one's own movements. © 2014.