Yevhen Hlushchuk - Academia.edu (original) (raw)
Papers by Yevhen Hlushchuk
Neuroimage, 2009
Competition imposes constraints for humans who make decisions. Concomitantly, people do not only ... more Competition imposes constraints for humans who make decisions. Concomitantly, people do not only maximize their personal profit but they also try to punish unfair conspecifics. In bargaining games, subjects typically accept equal-share offers but reject unduly small offers; competition affects this balance. Here we used functional magnetic resonance imaging (fMRI) to study adjustment to competition in a bargaining game where
Neuroimage, 2006
Vibrotactile stimuli can facilitate hearing, both in hearing-impaired and in normally hearing peo... more Vibrotactile stimuli can facilitate hearing, both in hearing-impaired and in normally hearing people. Accordingly, the sounds of hands exploring a surface contribute to the explorer's haptic percepts. As a possible brain basis of such phenomena, functional brain imaging has identified activations specific to audiotactile interaction in secondary somatosensory cortex, auditory belt area, and posterior parietal cortex, depending on the quality
PLOS ONE, 2015
Previous studies have shown that the hemodynamic response of the primary somatosensory cortex (SI... more Previous studies have shown that the hemodynamic response of the primary somatosensory cortex (SI) to electrical median nerve stimulation doubles in strength when the stimulus rate (SR) increases from 1 to 5 Hz. Here we investigated whether such sensitivity to SR is homogenous within the functionally different subareas of the SI cortex, and whether SR sensitivity would help discern area 3b among the other SI subareas. We acquired 3-tesla functional magnetic resonance imaging (fMRI) data from nine healthy adults who received pneumotactile stimuli in 25-s blocks to three right-hand fingers, either at 1, 4, or 10 Hz. The main contrast (all stimulations pooled vs. baseline), applied to the whole brain, first limited the search to the whole SI cortex. The conjunction of SR-sensitive contrasts [4 Hz - 1 Hz] > 0 and [10 Hz - 1 Hz] > 0 ([4Hz - 1Hz] + [10Hz - 1Hz] > 0), applied to the SI cluster, then revealed an anterior-ventral subcluster that reacted more strongly to both 10-Hz and 4-Hz stimuli than to the 1-Hz stimuli. No other SR-sensitive clusters were found at the group-level in the whole-brain analysis. The site of the SR-sensitive SI subcluster corresponds to the canonical position of area 3b; such differentiation was also possible at the individual level in 5 out of 9 subjects. Thus the SR sensitivity of the BOLD response appears to discern area 3b among other subareas of the human SI cortex.
The Journal of neuroscience : the official journal of the Society for Neuroscience, Jan 24, 2006
The whole human primary somatosensory (SI) cortex is activated by contralateral tactile stimuli, ... more The whole human primary somatosensory (SI) cortex is activated by contralateral tactile stimuli, whereas its subarea 2 displays neuronal responses also to ipsilateral stimuli. Here we report on a transient deactivation of area 3b of the ipsilateral SI during long-lasting tactile stimulation. We collected functional magnetic resonance imaging data with a 3 T scanner from 10 healthy adult subjects while tactile pulses were delivered at 1, 4, or 10 Hz in 25 s blocks to three right-hand fingers. In the contralateral SI cortex, activation [positive blood oxygenation level-dependent (BOLD) response] outlasted the stimulus blocks by 20 s, with an average duration of 45 s. In contrast, a transient deactivation (negative BOLD response) occurred in the ipsilateral rolandic cortex with an average duration of 18 s. Additional recordings on 10 subjects confirmed that the deactivation was not limited to the right SI but occurred in the SI cortex ipsilateral to the stimulated hand. Moreover, the p...
NeuroImage, 2004
In area 3b of the monkey primary somatosensory cortex SI, the proximal phalanges of the fingers a... more In area 3b of the monkey primary somatosensory cortex SI, the proximal phalanges of the fingers are represented close to the surface and the fingertips in the depth of the central sulcus. To study whether a similar arrangement might exist in humans, we applied tactile stimuli to the distal and proximal phalanges of the index finger in 11 healthy adults. Cortical somatosensory evoked fields were recorded with a whole-scalp neuromagnetometer. The sources of the responses were situated in the posterior wall of the central sulcus, statistically significantly more superior to proximal than distal stimuli, with a mean difference of 3.1 mm. Thus the distal-to-proximal representation of the index finger shows a similar order in human and monkey SI cortex. D
Proceedings of the National Academy of Sciences, 2010
In the absence of external stimuli, human hemodynamic brain activity displays slow intrinsic vari... more In the absence of external stimuli, human hemodynamic brain activity displays slow intrinsic variations. To find out whether such fluctuations would be altered by persistent pain, we asked 10 patients with unrelenting chronic pain of different etiologies and 10 sex-and agematched control subjects to rest with eyes open during 3-T functional MRI. Independent component analysis was used to identify functionally coupled brain networks. Time courses of an independent component comprising the insular cortices of both hemispheres showed stronger spectral power at 0.12 to 0.25 Hz in patients than in control subjects, with the largest difference at 0.16 Hz. A similar but weaker effect was seen in the anterior cingulate cortex, whereas activity of the precuneus and early visual cortex, used as a control site, did not differ between the groups. In the patient group, seed pointbased correlation analysis revealed altered spatial connectivity between insulae and anterior cingulate cortex. The results imply both temporally and spatially aberrant activity of the affective painprocessing areas in patients suffering from chronic pain. The accentuated 0.12-to 0.25-Hz fluctuations in the patient group might be related to altered activity of the autonomic nervous system. functional MRI | insula | resting state | autonomic nervous system | human A cute pain has an important protective function and is supported by a well-known brain network comprising the insular cortex, anterior cingulate cortex (ACC), primary and secondary somatosensory cortex, and thalamus (1). When pain becomes chronic, its physiological protective function is lost. Chronic pain decreases the quality of life and interferes with the cognitive, affective, and physical functioning. Although one-fifth of the Western population suffers from chronic pain (2), the underlying brain activity is poorly understood.
PLoS ONE, 2012
Independent component analysis (ICA) can unravel functional brain networks from functional magnet... more Independent component analysis (ICA) can unravel functional brain networks from functional magnetic resonance imaging (fMRI) data. The number of the estimated components affects both the spatial pattern of the identified networks and their time-course estimates. Here group-ICA was applied at four dimensionalities (10, 20, 40, and 58 components) to fMRI data collected from 15 subjects who viewed a 15-min silent film (''At land'' by Maya Deren). We focused on the dorsal attention network, the default-mode network, and the sensorimotor network. The lowest dimensionalities demonstrated most prominent activity within the dorsal attention network, combined with the visual areas, and in the default-mode network; the sensorimotor network only appeared with ICA comprising at least 20 components. The results suggest that even very low-dimensional ICA can unravel the most prominent functionally-connected brain networks. However, increasing the number of components gives a more detailed picture and functionally feasible subdivision of the major networks. These results improve our understanding of the hierarchical subdivision of brain networks during viewing of a movie that provides continuous stimulation embedded in an attention-directing narrative.
PAIN, 2009
A recent study described for the first time a patient group that suffered from spontaneous chroni... more A recent study described for the first time a patient group that suffered from spontaneous chronic pain and from recurrent herpes simplex virus (HSV) infections. The patients had pain in widespread areas on one side of the body and were--due to subtle immunological abnormalities--susceptible to HSV infections. Although the clinical features of the pain suggested involvement of the central nervous system, supporting evidence for this was lacking. The objective of this study was to search for changes in the central nervous system that could account for the chronic pain in these patients. We monitored the central processing of pain and touch in eight patients and 11 healthy control subjects, who received painful heat and innocuous tactile stimuli to the hands during functional magnetic resonance imaging. Possible changes in the gray matter density of the brain were assessed with voxel-based morphometry. We found functional changes in the patients' central pain circuitry: activation to heat pain was weaker than in control subjects in the insular cortices, anterior cingulate cortex (ACC), and thalamus, while the activations to innocuous tactile stimuli were similar in both groups. Gray matter density was decreased in the patients' frontal and prefrontal cortices and in the ACC. The observed functional and structural changes in the central pain circuitry, together with the clinical features of the chronic pain support the hypothesis for central involvement in the development of chronic pain in these patients.
NeuroImage, 2006
Citation 1: Schurmann M, Caetano G, Hlushchuk Y, Jousmaki V, Hari R. Touch activates human audito... more Citation 1: Schurmann M, Caetano G, Hlushchuk Y, Jousmaki V, Hari R. Touch activates human auditory cortex. NeuroImage. 2006; 30:1325-1331 The aim of Schurmann and colleagues study was to determine if auditory areas of the brain could be activated by somatosensory information. More specifically, the authors sought to observe and describe overlapping cortical areas, which are coactivated by vibrotactile and auditory input. Additionally, the authors investigated if differences between vibrotactile and tactile stimulation existed.
NeuroImage, 2009
Competition imposes constraints for humans who make decisions. Concomitantly, people do not only ... more Competition imposes constraints for humans who make decisions. Concomitantly, people do not only maximize their personal profit but they also try to punish unfair conspecifics. In bargaining games, subjects typically accept equal-share offers but reject unduly small offers; competition affects this balance. Here we used functional magnetic resonance imaging (fMRI) to study adjustment to competition in a bargaining game where subjects competed against another person for a share of the stake. For medium-sized, but not for minimum offers, competition increased the likelihood of acceptance and thus shifted behavior towards maximizing personal profits, emphasizing the importance of financial incentives. Specifically for medium-sized offers, competition was associated with increased brain activation bilaterally in the temporo-parietal junction, a region associated with mentalizing. In the right inferior frontal region, competition-related brain activation was strongest in subjects whose high acceptance rates in the standard ultimatum game hinted at a profit-oriented approach. The results suggest a network of brain areas supporting decision making under competition, with incentive-dependent mentalizing engaged when the competitor's behavior is difficult to predict and when the stake is attractive enough to justify the effort.
NeuroImage, 2007
In search for suitable tools to study brain activation in natural environments, where the stimuli... more In search for suitable tools to study brain activation in natural environments, where the stimuli are multimodal, poorly predictable and irregularly varying, we collected functional magnetic resonance imaging data from 6 subjects during a continuous 8-min stimulus sequence that comprised auditory (speech or tone pips), visual (video clips dominated by faces, hands, or buildings), and tactile finger stimuli in blocks of 6-33 s. Results obtained by independent component analysis (ICA) and general-linear-model-based analysis (GLM) were compared.
Human Brain Mapping, 2011
Bodily abnormalities in other persons often evoke an uneasy feeling, even disgust. Here, we studi... more Bodily abnormalities in other persons often evoke an uneasy feeling, even disgust. Here, we studied the brain basis of such perceptual salience by presenting static pictures of distorted hand postures to healthy subjects during functional magnetic resonance imaging. Cortical activation sensitive to distorted (vs. natural) finger postures was found-with right-hemispheric dominance-in the primary motor cortex, postcentral somatosensory areas, amygdala, and insula, and bilaterally in the putamen. This activation pattern suggests that the instantaneous ''gut feelings'' during the observation of bodily distortions in others are related to embodied percepts that also involve affect-related brain areas. Hum Brain Mapp 32:612-623, in Wiley Online Library (wileyonlinelibrary.com). V C 2010 Wiley-Liss, Inc. r Embodied Visual Perception of Finger Postures r r 613 r fMRI Evaluation-Preprocessing in SPM2 Preprocessing in SPM2 [Wellcome Department of Imaging Neuroscience, London, UK; Friston et al., 1995] r Schü rmann et al. r r 614 r r Embodied Visual Perception of Finger Postures r r 615 r r Embodied Visual Perception of Finger Postures r r 617 r
Human Brain Mapping, 2011
In models of letter recognition, handwritten letters are considered as a particular font exemplar... more In models of letter recognition, handwritten letters are considered as a particular font exemplar, not qualitatively different in their processing from printed letters. Yet, some data suggest that recognizing handwritten letters might rely on distinct processes, possibly related to motor knowledge. We applied functional magnetic resonance imaging to compare the neural correlates of perceiving handwritten letters vs. standard printed letters. Statistical analysis circumscribed to frontal brain regions involved in hand-movement triggering and execution showed that processing of handwritten letters is supported by a stronger activation of the left primary motor cortex and the supplementary motor area. At the whole-brain level, additional differences between handwritten and printed letters were observed in the right superior frontal, middle occipital, and parahippocampal gyri, and in the left inferior precentral and the fusiform gyri. The results are suggested to indicate embodiment of the visual perception of handwritten letters. Hum Brain Mapp 32:1250-1259,
Human Brain Mapping, 2009
With increasing stimulus rate (SR), cortical EEG and MEG responses typically decrease in amplitud... more With increasing stimulus rate (SR), cortical EEG and MEG responses typically decrease in amplitude whereas BOLD fMRI signals increase. To address this discrepancy, we predicted BOLD responses with squared MEG waveforms using a recently proposed energy-density model. Tactile stimuli were delivered to finger tips at SRs of 1, 4, or 10 Hz in successive 25-s blocks, and brain signals were detected from area 3b of the primary somatosensory cortex of nine healthy adults using a 306-channel whole-scalp neuromagnetometer and a 3-T fMRI magnet. The main MEG deflections decreased in amplitude as a function of SR, whereas the BOLD signals increased from 1- to 4-Hz SR, with no further change at 10 Hz. MEG energy densities, obtained over the whole stimulus train and convolved with different hemodynamic response functions, predicted both the shape and amplitude of the BOLD signals well, and incorporation of nonlinear terms into the model did not offer any further advantage. Thus, squared MEG waveforms obtained over the entire stimulus train provided an appropriate estimate of area 3b neuronal activity associated with the BOLD signal.
Experimental Brain Research, 2006
Functional magnetic resonance imaging (fMRI) can reveal human brain activations with high precisi... more Functional magnetic resonance imaging (fMRI) can reveal human brain activations with high precision. The accuracy may, however, be impaired by movement and deformation of brain tissue associated with cardiac pulsations. Here we corrected for such artifacts by time-locking the fMRI data acquisition to the cardiac cycle in ten subjects who received tactile stimuli to their lips, fingers, and toes. The imaged brain areas covered the parietal operculum and the thalamus, including the secondary somatosensory cortex (SII) bilaterally. Variance of the blood-oxygen-level-dependent signal decreased on average by 38-40% in the SII cortex and by 26% in the thalamus during cardiac triggering compared with conventional imaging. Consequently, statistically significant responses were seen both in the SII cortex and in the ventroposterior thalamus in a larger number of subjects. At the cortical level, the activation pattern revealed two distinct representations for both fingers and toes in the SII region, and the more medial representations were detected with enhanced clarity during cardiac-triggered imaging. In the group-level analysis, the thalamic response to finger stimulation was seen with cardiac triggering, only.
Cerebral Cortex, 2006
Understanding another person's experience draws on ''mirroring systems,'' brain circuitries share... more Understanding another person's experience draws on ''mirroring systems,'' brain circuitries shared by the subject's own actions/ feelings and by similar states observed in others. Lately, also the experience of pain has been shown to activate partly the same brain areas in the subjects' own and in the observer's brain. Recent studies show remarkable overlap between brain areas activated when a subject undergoes painful sensory stimulation and when he/she observes others suffering from pain. Using functional magnetic resonance imaging, we show that not only the presence of pain but also the intensity of the observed pain is encoded in the observer's brain-as occurs during the observer's own pain experience. When subjects observed pain from the faces of chronic pain patients, activations in bilateral anterior insula (AI), left anterior cingulate cortex, and left inferior parietal lobe in the observer's brain correlated with their estimates of the intensity of observed pain. Furthermore, the strengths of activation in the left AI and left inferior frontal gyrus during observation of intensified pain correlated with subjects' self-rated empathy. These findings imply that the intersubjective representation of pain in the human brain is more detailed than has been previously thought.
16th Annual Meeting of the Organization for Human Brain Mapping. Barcelona, Spain, 2010
A fifth of the western population suffers from chronic pain, the brain pathophysiology of which i... more A fifth of the western population suffers from chronic pain, the brain pathophysiology of which is still poorly understood. We recently found that patients suffering from chronic pain displayed both temporally and spatially aberrant activity evident in resting-state functional magnetic resonance imaging (fMRI). Seed-based connectivity analysis revealed altered functional connectivity between the patients' insulae and anterior cingulate cortex (Malinen et al., under revision).
One of the challenges of naturalistic neurosciences using movie-viewing experiments is how to int... more One of the challenges of naturalistic neurosciences using movie-viewing experiments is how to interpret observed
brain activations in relation to the multiplicity of time-locked stimulus features. As previous studies
have shown less inter-subject synchronization across viewers of random video footage than story-driven films,
new methods need to be developed for analysis of less story-driven contents. To optimize the linkage between
our fMRI data collected during viewing of a deliberately non-narrative silent film ‘At Land’ by Maya Deren
(1944) and its annotated content, we combined the method of elastic-net regularization with the modeldriven
linear regression and the well-established data-driven independent component analysis (ICA) and
inter-subject correlation (ISC) methods. In the linear regression analysis, both IC and region-of-interest (ROI)
time-series were fitted with time-series of a total of 36 binary-valued and one real-valued tactile annotation of
film features. The elastic-net regularization and cross-validation were applied in the ordinary least-squares linear
regression in order to avoid over-fitting due to the multicollinearity of regressors, the results were compared
against both the partial least-squares (PLS) regression and the un-regularized full-model regression. Nonparametric
permutation testing scheme was applied to evaluate the statistical significance of regression. We
found statistically significant correlation between the annotationmodel and 9 ICs out of 40 ICs. Regression analysis
was also repeated for a large set of cubic ROIs covering the grey matter. Both IC- and ROI-based regression
analyses revealed activations in parietal and occipital regions, with additional smaller clusters in the frontal
lobe. Furthermore, we found elastic-net based regression more sensitive than PLS and un-regularized regression
since it detected a larger number of significant ICs and ROIs. Along with the ISC rankingmethods, our regression
analysis proved a feasible method for ordering the ICs based on their functional relevance to the annotated
cinematic features. The novelty of our method is – in comparison to the hypothesis-driven manual preselection
and observation of some individual regressors biased by choice – in applying data-driven approach to
all content features simultaneously. We found especially the combination of regularized regression and ICA
useful when analyzing fMRI data obtained using non-narrative movie stimulus with a large set of complex and
correlated features.
© 2015 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license
(http://creativecommons.org/licenses/by/4.0/).
Neuroimage, 2009
Competition imposes constraints for humans who make decisions. Concomitantly, people do not only ... more Competition imposes constraints for humans who make decisions. Concomitantly, people do not only maximize their personal profit but they also try to punish unfair conspecifics. In bargaining games, subjects typically accept equal-share offers but reject unduly small offers; competition affects this balance. Here we used functional magnetic resonance imaging (fMRI) to study adjustment to competition in a bargaining game where
Neuroimage, 2006
Vibrotactile stimuli can facilitate hearing, both in hearing-impaired and in normally hearing peo... more Vibrotactile stimuli can facilitate hearing, both in hearing-impaired and in normally hearing people. Accordingly, the sounds of hands exploring a surface contribute to the explorer's haptic percepts. As a possible brain basis of such phenomena, functional brain imaging has identified activations specific to audiotactile interaction in secondary somatosensory cortex, auditory belt area, and posterior parietal cortex, depending on the quality
PLOS ONE, 2015
Previous studies have shown that the hemodynamic response of the primary somatosensory cortex (SI... more Previous studies have shown that the hemodynamic response of the primary somatosensory cortex (SI) to electrical median nerve stimulation doubles in strength when the stimulus rate (SR) increases from 1 to 5 Hz. Here we investigated whether such sensitivity to SR is homogenous within the functionally different subareas of the SI cortex, and whether SR sensitivity would help discern area 3b among the other SI subareas. We acquired 3-tesla functional magnetic resonance imaging (fMRI) data from nine healthy adults who received pneumotactile stimuli in 25-s blocks to three right-hand fingers, either at 1, 4, or 10 Hz. The main contrast (all stimulations pooled vs. baseline), applied to the whole brain, first limited the search to the whole SI cortex. The conjunction of SR-sensitive contrasts [4 Hz - 1 Hz] > 0 and [10 Hz - 1 Hz] > 0 ([4Hz - 1Hz] + [10Hz - 1Hz] > 0), applied to the SI cluster, then revealed an anterior-ventral subcluster that reacted more strongly to both 10-Hz and 4-Hz stimuli than to the 1-Hz stimuli. No other SR-sensitive clusters were found at the group-level in the whole-brain analysis. The site of the SR-sensitive SI subcluster corresponds to the canonical position of area 3b; such differentiation was also possible at the individual level in 5 out of 9 subjects. Thus the SR sensitivity of the BOLD response appears to discern area 3b among other subareas of the human SI cortex.
The Journal of neuroscience : the official journal of the Society for Neuroscience, Jan 24, 2006
The whole human primary somatosensory (SI) cortex is activated by contralateral tactile stimuli, ... more The whole human primary somatosensory (SI) cortex is activated by contralateral tactile stimuli, whereas its subarea 2 displays neuronal responses also to ipsilateral stimuli. Here we report on a transient deactivation of area 3b of the ipsilateral SI during long-lasting tactile stimulation. We collected functional magnetic resonance imaging data with a 3 T scanner from 10 healthy adult subjects while tactile pulses were delivered at 1, 4, or 10 Hz in 25 s blocks to three right-hand fingers. In the contralateral SI cortex, activation [positive blood oxygenation level-dependent (BOLD) response] outlasted the stimulus blocks by 20 s, with an average duration of 45 s. In contrast, a transient deactivation (negative BOLD response) occurred in the ipsilateral rolandic cortex with an average duration of 18 s. Additional recordings on 10 subjects confirmed that the deactivation was not limited to the right SI but occurred in the SI cortex ipsilateral to the stimulated hand. Moreover, the p...
NeuroImage, 2004
In area 3b of the monkey primary somatosensory cortex SI, the proximal phalanges of the fingers a... more In area 3b of the monkey primary somatosensory cortex SI, the proximal phalanges of the fingers are represented close to the surface and the fingertips in the depth of the central sulcus. To study whether a similar arrangement might exist in humans, we applied tactile stimuli to the distal and proximal phalanges of the index finger in 11 healthy adults. Cortical somatosensory evoked fields were recorded with a whole-scalp neuromagnetometer. The sources of the responses were situated in the posterior wall of the central sulcus, statistically significantly more superior to proximal than distal stimuli, with a mean difference of 3.1 mm. Thus the distal-to-proximal representation of the index finger shows a similar order in human and monkey SI cortex. D
Proceedings of the National Academy of Sciences, 2010
In the absence of external stimuli, human hemodynamic brain activity displays slow intrinsic vari... more In the absence of external stimuli, human hemodynamic brain activity displays slow intrinsic variations. To find out whether such fluctuations would be altered by persistent pain, we asked 10 patients with unrelenting chronic pain of different etiologies and 10 sex-and agematched control subjects to rest with eyes open during 3-T functional MRI. Independent component analysis was used to identify functionally coupled brain networks. Time courses of an independent component comprising the insular cortices of both hemispheres showed stronger spectral power at 0.12 to 0.25 Hz in patients than in control subjects, with the largest difference at 0.16 Hz. A similar but weaker effect was seen in the anterior cingulate cortex, whereas activity of the precuneus and early visual cortex, used as a control site, did not differ between the groups. In the patient group, seed pointbased correlation analysis revealed altered spatial connectivity between insulae and anterior cingulate cortex. The results imply both temporally and spatially aberrant activity of the affective painprocessing areas in patients suffering from chronic pain. The accentuated 0.12-to 0.25-Hz fluctuations in the patient group might be related to altered activity of the autonomic nervous system. functional MRI | insula | resting state | autonomic nervous system | human A cute pain has an important protective function and is supported by a well-known brain network comprising the insular cortex, anterior cingulate cortex (ACC), primary and secondary somatosensory cortex, and thalamus (1). When pain becomes chronic, its physiological protective function is lost. Chronic pain decreases the quality of life and interferes with the cognitive, affective, and physical functioning. Although one-fifth of the Western population suffers from chronic pain (2), the underlying brain activity is poorly understood.
PLoS ONE, 2012
Independent component analysis (ICA) can unravel functional brain networks from functional magnet... more Independent component analysis (ICA) can unravel functional brain networks from functional magnetic resonance imaging (fMRI) data. The number of the estimated components affects both the spatial pattern of the identified networks and their time-course estimates. Here group-ICA was applied at four dimensionalities (10, 20, 40, and 58 components) to fMRI data collected from 15 subjects who viewed a 15-min silent film (''At land'' by Maya Deren). We focused on the dorsal attention network, the default-mode network, and the sensorimotor network. The lowest dimensionalities demonstrated most prominent activity within the dorsal attention network, combined with the visual areas, and in the default-mode network; the sensorimotor network only appeared with ICA comprising at least 20 components. The results suggest that even very low-dimensional ICA can unravel the most prominent functionally-connected brain networks. However, increasing the number of components gives a more detailed picture and functionally feasible subdivision of the major networks. These results improve our understanding of the hierarchical subdivision of brain networks during viewing of a movie that provides continuous stimulation embedded in an attention-directing narrative.
PAIN, 2009
A recent study described for the first time a patient group that suffered from spontaneous chroni... more A recent study described for the first time a patient group that suffered from spontaneous chronic pain and from recurrent herpes simplex virus (HSV) infections. The patients had pain in widespread areas on one side of the body and were--due to subtle immunological abnormalities--susceptible to HSV infections. Although the clinical features of the pain suggested involvement of the central nervous system, supporting evidence for this was lacking. The objective of this study was to search for changes in the central nervous system that could account for the chronic pain in these patients. We monitored the central processing of pain and touch in eight patients and 11 healthy control subjects, who received painful heat and innocuous tactile stimuli to the hands during functional magnetic resonance imaging. Possible changes in the gray matter density of the brain were assessed with voxel-based morphometry. We found functional changes in the patients' central pain circuitry: activation to heat pain was weaker than in control subjects in the insular cortices, anterior cingulate cortex (ACC), and thalamus, while the activations to innocuous tactile stimuli were similar in both groups. Gray matter density was decreased in the patients' frontal and prefrontal cortices and in the ACC. The observed functional and structural changes in the central pain circuitry, together with the clinical features of the chronic pain support the hypothesis for central involvement in the development of chronic pain in these patients.
NeuroImage, 2006
Citation 1: Schurmann M, Caetano G, Hlushchuk Y, Jousmaki V, Hari R. Touch activates human audito... more Citation 1: Schurmann M, Caetano G, Hlushchuk Y, Jousmaki V, Hari R. Touch activates human auditory cortex. NeuroImage. 2006; 30:1325-1331 The aim of Schurmann and colleagues study was to determine if auditory areas of the brain could be activated by somatosensory information. More specifically, the authors sought to observe and describe overlapping cortical areas, which are coactivated by vibrotactile and auditory input. Additionally, the authors investigated if differences between vibrotactile and tactile stimulation existed.
NeuroImage, 2009
Competition imposes constraints for humans who make decisions. Concomitantly, people do not only ... more Competition imposes constraints for humans who make decisions. Concomitantly, people do not only maximize their personal profit but they also try to punish unfair conspecifics. In bargaining games, subjects typically accept equal-share offers but reject unduly small offers; competition affects this balance. Here we used functional magnetic resonance imaging (fMRI) to study adjustment to competition in a bargaining game where subjects competed against another person for a share of the stake. For medium-sized, but not for minimum offers, competition increased the likelihood of acceptance and thus shifted behavior towards maximizing personal profits, emphasizing the importance of financial incentives. Specifically for medium-sized offers, competition was associated with increased brain activation bilaterally in the temporo-parietal junction, a region associated with mentalizing. In the right inferior frontal region, competition-related brain activation was strongest in subjects whose high acceptance rates in the standard ultimatum game hinted at a profit-oriented approach. The results suggest a network of brain areas supporting decision making under competition, with incentive-dependent mentalizing engaged when the competitor's behavior is difficult to predict and when the stake is attractive enough to justify the effort.
NeuroImage, 2007
In search for suitable tools to study brain activation in natural environments, where the stimuli... more In search for suitable tools to study brain activation in natural environments, where the stimuli are multimodal, poorly predictable and irregularly varying, we collected functional magnetic resonance imaging data from 6 subjects during a continuous 8-min stimulus sequence that comprised auditory (speech or tone pips), visual (video clips dominated by faces, hands, or buildings), and tactile finger stimuli in blocks of 6-33 s. Results obtained by independent component analysis (ICA) and general-linear-model-based analysis (GLM) were compared.
Human Brain Mapping, 2011
Bodily abnormalities in other persons often evoke an uneasy feeling, even disgust. Here, we studi... more Bodily abnormalities in other persons often evoke an uneasy feeling, even disgust. Here, we studied the brain basis of such perceptual salience by presenting static pictures of distorted hand postures to healthy subjects during functional magnetic resonance imaging. Cortical activation sensitive to distorted (vs. natural) finger postures was found-with right-hemispheric dominance-in the primary motor cortex, postcentral somatosensory areas, amygdala, and insula, and bilaterally in the putamen. This activation pattern suggests that the instantaneous ''gut feelings'' during the observation of bodily distortions in others are related to embodied percepts that also involve affect-related brain areas. Hum Brain Mapp 32:612-623, in Wiley Online Library (wileyonlinelibrary.com). V C 2010 Wiley-Liss, Inc. r Embodied Visual Perception of Finger Postures r r 613 r fMRI Evaluation-Preprocessing in SPM2 Preprocessing in SPM2 [Wellcome Department of Imaging Neuroscience, London, UK; Friston et al., 1995] r Schü rmann et al. r r 614 r r Embodied Visual Perception of Finger Postures r r 615 r r Embodied Visual Perception of Finger Postures r r 617 r
Human Brain Mapping, 2011
In models of letter recognition, handwritten letters are considered as a particular font exemplar... more In models of letter recognition, handwritten letters are considered as a particular font exemplar, not qualitatively different in their processing from printed letters. Yet, some data suggest that recognizing handwritten letters might rely on distinct processes, possibly related to motor knowledge. We applied functional magnetic resonance imaging to compare the neural correlates of perceiving handwritten letters vs. standard printed letters. Statistical analysis circumscribed to frontal brain regions involved in hand-movement triggering and execution showed that processing of handwritten letters is supported by a stronger activation of the left primary motor cortex and the supplementary motor area. At the whole-brain level, additional differences between handwritten and printed letters were observed in the right superior frontal, middle occipital, and parahippocampal gyri, and in the left inferior precentral and the fusiform gyri. The results are suggested to indicate embodiment of the visual perception of handwritten letters. Hum Brain Mapp 32:1250-1259,
Human Brain Mapping, 2009
With increasing stimulus rate (SR), cortical EEG and MEG responses typically decrease in amplitud... more With increasing stimulus rate (SR), cortical EEG and MEG responses typically decrease in amplitude whereas BOLD fMRI signals increase. To address this discrepancy, we predicted BOLD responses with squared MEG waveforms using a recently proposed energy-density model. Tactile stimuli were delivered to finger tips at SRs of 1, 4, or 10 Hz in successive 25-s blocks, and brain signals were detected from area 3b of the primary somatosensory cortex of nine healthy adults using a 306-channel whole-scalp neuromagnetometer and a 3-T fMRI magnet. The main MEG deflections decreased in amplitude as a function of SR, whereas the BOLD signals increased from 1- to 4-Hz SR, with no further change at 10 Hz. MEG energy densities, obtained over the whole stimulus train and convolved with different hemodynamic response functions, predicted both the shape and amplitude of the BOLD signals well, and incorporation of nonlinear terms into the model did not offer any further advantage. Thus, squared MEG waveforms obtained over the entire stimulus train provided an appropriate estimate of area 3b neuronal activity associated with the BOLD signal.
Experimental Brain Research, 2006
Functional magnetic resonance imaging (fMRI) can reveal human brain activations with high precisi... more Functional magnetic resonance imaging (fMRI) can reveal human brain activations with high precision. The accuracy may, however, be impaired by movement and deformation of brain tissue associated with cardiac pulsations. Here we corrected for such artifacts by time-locking the fMRI data acquisition to the cardiac cycle in ten subjects who received tactile stimuli to their lips, fingers, and toes. The imaged brain areas covered the parietal operculum and the thalamus, including the secondary somatosensory cortex (SII) bilaterally. Variance of the blood-oxygen-level-dependent signal decreased on average by 38-40% in the SII cortex and by 26% in the thalamus during cardiac triggering compared with conventional imaging. Consequently, statistically significant responses were seen both in the SII cortex and in the ventroposterior thalamus in a larger number of subjects. At the cortical level, the activation pattern revealed two distinct representations for both fingers and toes in the SII region, and the more medial representations were detected with enhanced clarity during cardiac-triggered imaging. In the group-level analysis, the thalamic response to finger stimulation was seen with cardiac triggering, only.
Cerebral Cortex, 2006
Understanding another person's experience draws on ''mirroring systems,'' brain circuitries share... more Understanding another person's experience draws on ''mirroring systems,'' brain circuitries shared by the subject's own actions/ feelings and by similar states observed in others. Lately, also the experience of pain has been shown to activate partly the same brain areas in the subjects' own and in the observer's brain. Recent studies show remarkable overlap between brain areas activated when a subject undergoes painful sensory stimulation and when he/she observes others suffering from pain. Using functional magnetic resonance imaging, we show that not only the presence of pain but also the intensity of the observed pain is encoded in the observer's brain-as occurs during the observer's own pain experience. When subjects observed pain from the faces of chronic pain patients, activations in bilateral anterior insula (AI), left anterior cingulate cortex, and left inferior parietal lobe in the observer's brain correlated with their estimates of the intensity of observed pain. Furthermore, the strengths of activation in the left AI and left inferior frontal gyrus during observation of intensified pain correlated with subjects' self-rated empathy. These findings imply that the intersubjective representation of pain in the human brain is more detailed than has been previously thought.
16th Annual Meeting of the Organization for Human Brain Mapping. Barcelona, Spain, 2010
A fifth of the western population suffers from chronic pain, the brain pathophysiology of which i... more A fifth of the western population suffers from chronic pain, the brain pathophysiology of which is still poorly understood. We recently found that patients suffering from chronic pain displayed both temporally and spatially aberrant activity evident in resting-state functional magnetic resonance imaging (fMRI). Seed-based connectivity analysis revealed altered functional connectivity between the patients' insulae and anterior cingulate cortex (Malinen et al., under revision).
One of the challenges of naturalistic neurosciences using movie-viewing experiments is how to int... more One of the challenges of naturalistic neurosciences using movie-viewing experiments is how to interpret observed
brain activations in relation to the multiplicity of time-locked stimulus features. As previous studies
have shown less inter-subject synchronization across viewers of random video footage than story-driven films,
new methods need to be developed for analysis of less story-driven contents. To optimize the linkage between
our fMRI data collected during viewing of a deliberately non-narrative silent film ‘At Land’ by Maya Deren
(1944) and its annotated content, we combined the method of elastic-net regularization with the modeldriven
linear regression and the well-established data-driven independent component analysis (ICA) and
inter-subject correlation (ISC) methods. In the linear regression analysis, both IC and region-of-interest (ROI)
time-series were fitted with time-series of a total of 36 binary-valued and one real-valued tactile annotation of
film features. The elastic-net regularization and cross-validation were applied in the ordinary least-squares linear
regression in order to avoid over-fitting due to the multicollinearity of regressors, the results were compared
against both the partial least-squares (PLS) regression and the un-regularized full-model regression. Nonparametric
permutation testing scheme was applied to evaluate the statistical significance of regression. We
found statistically significant correlation between the annotationmodel and 9 ICs out of 40 ICs. Regression analysis
was also repeated for a large set of cubic ROIs covering the grey matter. Both IC- and ROI-based regression
analyses revealed activations in parietal and occipital regions, with additional smaller clusters in the frontal
lobe. Furthermore, we found elastic-net based regression more sensitive than PLS and un-regularized regression
since it detected a larger number of significant ICs and ROIs. Along with the ISC rankingmethods, our regression
analysis proved a feasible method for ordering the ICs based on their functional relevance to the annotated
cinematic features. The novelty of our method is – in comparison to the hypothesis-driven manual preselection
and observation of some individual regressors biased by choice – in applying data-driven approach to
all content features simultaneously. We found especially the combination of regularized regression and ICA
useful when analyzing fMRI data obtained using non-narrative movie stimulus with a large set of complex and
correlated features.
© 2015 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license
(http://creativecommons.org/licenses/by/4.0/).