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  • 1.
    Björnsdotter, Malin
    et al.
    Department of Physiology, Institute for Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden.
    Gordon, Ilanit
    Child Study Center, Yale University, New Haven, CT, USA.
    Pelphrey, Kevin A
    Child Study Center, Yale University, New Haven, CT, USA.
    Olausson, Håkan
    Department of Physiology, Institute for Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden.
    Kaiser, Martha D
    Child Study Center, Yale University, New Haven, CT, USA.
    Development of brain mechanisms for processing affective touch2014In: Frontiers in Behavioral Neuroscience, ISSN 1662-5153, E-ISSN 1662-5153, Vol. 8, no 24Article in journal (Refereed)
    Abstract [en]

    Affective tactile stimulation plays a key role in the maturation of neural circuits, but the development of brain mechanisms processing touch is poorly understood. We therefore used functional magnetic resonance imaging (fMRI) to study brain responses to soft brush stroking of both glabrous (palm) and hairy (forearm) skin in healthy children (5-13 years), adolescents (14-17 years), and adults (25-35 years). Adult-defined regions-of-interests in the primary somatosensory cortex (SI), secondary somatosensory cortex (SII), insular cortex and right posterior superior temporal sulcus (pSTS) were significantly and similarly activated in all age groups. Whole-brain analyses revealed that responses in the ipsilateral SII were positively correlated with age in both genders, and that responses in bilateral regions near the pSTS correlated significantly and strongly with age in females but not in males. These results suggest that brain mechanisms associated with both sensory-discriminative and affective-motivational aspects of touch are largely established in school-aged children, and that there is a general continuing maturation of SII and a female-specific increase in pSTS sensitivity with age. Our work establishes a groundwork for future comparative studies of tactile processing in developmental disorders characterized by disrupted social perception such as autism.

  • 2.
    Björnsdotter, Malin
    et al.
    Institute of Neuroscience and Physiology, University of Gothenburg, Göteborg, Sweden.
    Löken, Line
    Institute of Neuroscience and Physiology, University of Gothenburg, Göteborg, Sweden.
    Olausson, Håkan
    Institute of Neuroscience and Physiology, University of Gothenburg, Göteborg, Sweden.
    Vallbo, Åke
    Institute of Neuroscience and Physiology, University of Gothenburg, Göteborg, Sweden.
    Wessberg, Johan
    Institute of Neuroscience and Physiology, University of Gothenburg, Göteborg, Sweden.
    Somatotopic Organization of Gentle Touch Processing in the Posterior Insular Cortex2009In: Journal of Neuroscience, ISSN 0270-6474, E-ISSN 1529-2401, Vol. 29, no 29, p. 9314-9320Article in journal (Refereed)
    Abstract [en]

    A network of thin (C and A delta) afferents relays various signals related to the physiological condition of the body, including sensations of gentle touch, pain, and temperature changes. Such afferents project to the insular cortex, where a somatotopic organization of responses to noxious and cooling stimuli was recently observed. To explore the possibility of a corresponding body-map topography in relation to gentle touch mediated through C tactile (CT) fibers, we applied soft brush stimuli to the right forearm and thigh of a patient (GL) lacking A beta afferents, and six healthy subjects during functional magnetic resonance imaging (fMRI). For improved fMRI analysis, we used a highly sensitive multivariate voxel clustering approach. A somatotopic organization of the left (contralateral) posterior insular cortex was consistently demonstrated in all subjects, including GL, with forearm projecting anterior to thigh stimulation. Also, despite denying any sense of touch in daily life, GL correctly localized 97% of the stimuli to the forearm or thigh in a forced-choice paradigm. The consistency in activation patterns across GL and the healthy subjects suggests that the identified organization reflects the central projection of CT fibers. Moreover, substantial similarities of the presently observed insular activation with that described for noxious and cooling stimuli solidify the hypothesized sensory-affective role of the CT system in the maintenance of physical well-being as part of a thin-afferent homeostatic network.

  • 3.
    Björnsdotter, Malin
    et al.
    Institute for Neuroscience and Physiology, University of Gothenburg, Göteborg, Sweden.
    Morrison, India
    Institute for Neuroscience and Physiology, University of Gothenburg, Göteborg, Sweden.
    Olausson, Håkan
    Institute for Neuroscience and Physiology, University of Gothenburg, Göteborg, Sweden.
    Feeling good: on the role of C fiber mediated touch in interoception.2010In: Experimental Brain Research, ISSN 0014-4819, E-ISSN 1432-1106, Vol. 207, no 3, p. 149-155Article in journal (Refereed)
    Abstract [en]

    The human skin is innervated by a network of thin, slow-conducting afferent (C and Aδ) fibers, transmitting a diverse range of information. Classically, these fibers are described as thermo-, noci- or chemoreceptive, whereas mechanoreception is attributed exclusively to thick, fast-conducting (Aβ) afferents. A growing body of evidence, however, supports the notion that C tactile afferents comprise a second anatomically and functionally distinct system signaling touch in humans. This review discusses established as well as recent findings which highlight fundamental differences in peripheral and central information coding and processing between Aβ and C mechanoreception. We conclude that from the skin through the brain, C touch shares more characteristics with interoceptive modalities (e.g. pain, temperature, and itch) than exteroceptive Aβ touch, vision or hearing. In this light, we discuss the motivational-affective role of C touch as an integral part of a thin-fiber afferent homeostatic network for the maintenance of physical and social well-being.

  • 4.
    Björnsdotter, Malin
    et al.
    Institute of Neuroscience and Physiology, University of Gothenburg, Göteborg, Sweden.
    Nalin, Kajsa
    Centre of Interdisciplinary Research/Cognition/Information, University of Gothenburg, Göteborg, Sweden.
    Hansson, Lars-Erik
    Department of Surgery, Sahlgrenska University Hospital/Östra, Göteborg, Sweden.
    Malmgren, Helge
    Department of Philosophy, Linguistics and Theory of Science, University of Gothenburg, Göteborg, Sweden.
    Support Vector Machine Diagnosis of Acute Abdominal Pain2010In: Biomedical Engineering Systems and Technologies: International Joint Conference, BIOSTEC 2009 Porto, Portugal, January 14-17, 2009, Revised Selected Papers / [ed] Fred, Ana; Filipe, Joaquim; Gamboa, Hugo, Springer Berlin/Heidelberg, 2010, p. 347-355Chapter in book (Other academic)
    Abstract [en]

    This study explores the feasibility of a decision-support system for patients seeking care for acute abdominal pain, and, specifically the diagnosis of acute diverticulitis. We used a linear support vector machine (SVM) to separate diverticulitis from all other reported cases of abdominal pain and from the important differential diagnosis non-specific abdominal pain (NSAP). On a database containing 3337 patients, the SVM obtained results comparable to those of the doctors in separating diverticulitis or NSAP from the remaining diseases. The distinction between diverticulitis and NSAP was, however, substantially improved by the SVM. For this patient group, the doctors achieved a sensitivity of 0.714 and a specificity of 0.963. When adjusted to the physicians’ results, the SVM sensitivity/specificity was higher at 0.714/0.985 and 0.786/0.963 respectively. Age was found as the most important discriminative variable, closely followed by C-reactive protein level and lower left side pain.

  • 5.
    Björnsdotter, Malin
    et al.
    Department of Physiology, Institute of Neuroscience and Physiology, University of Gothenburg, Sweden.
    Rylander, Karin
    Department of Physiology, Institute of Neuroscience and Physiology, University of Gothenburg, Sweden.
    Wessberg, Johan
    Department of Physiology, Institute of Neuroscience and Physiology, University of Gothenburg, Sweden.
    A Monte Carlo method for locally multivariate brain mapping.2011In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 56, no 2, p. 508-516Article in journal (Refereed)
    Abstract [en]

    Locally multivariate approaches to functional brain mapping offer a highly appealing complement to conventional statistics, but require restrictive region-of-interest hypotheses, or, in exhaustive search forms (such as the "searchlight" algorithm; Kriegeskorte et al., 2006), are excessively computer intensive. We therefore propose a non-restrictive, comparatively fast yet highly sensitive method based on Monte Carlo approximation principles where locally multivariate maps are computed by averaging across voxelwise condition-discriminative information obtained from repeated stochastic sampling of fixed-size search volumes. On simulated data containing discriminative regions of varying size and contrast-to-noise ratio (CNR), the Monte Carlo method reduced the required computer resources by as much as 75% compared to the searchlight with no reduction in mapping performance. Notably, the Monte Carlo mapping approach not only outperformed the general linear method (GLM), but also produced higher discriminative voxel detection scores than the searchlight irrespective of classifier (linear or nonlinear support vector machine), discriminative region size or CNR. The improved performance was explained by the information-average procedure, and the Monte Carlo approach yielded mapping sensitivities of a few percent lower than an information-average exhaustive search. Finally, we demonstrate the utility of the algorithm on whole-brain, multi-subject functional magnetic resonance imaging (fMRI) data from a tactile study, revealing that the central representation of gentle touch is spatially distributed in somatosensory, insular and visual regions.

  • 6.
    Björnsdotter, Malin
    et al.
    Department of Physiology, Institute of Neuroscience and Physiology, University of Gothenburg, Göteborg, Sweden.
    Wessberg, Johan
    Department of Physiology, Institute of Neuroscience and Physiology, University of Gothenburg, Göteborg, Sweden.
    Clustered sampling improves random subspace brain mapping2012In: Pattern Recognition, ISSN 0031-3203, E-ISSN 1873-5142, Vol. 45, no 6, p. 2035-2040Article in journal (Refereed)
    Abstract [en]

    Intuitive and efficient, the random subspace ensemble approach provides an appealing solution to the problem of the vast dimensionality of functional magnetic resonance imaging (fMRI) data for maximal-accuracy brain state decoding. Recently, efforts to generate biologically plausible and interpretable maps of brain regions which contribute information to the ensemble decoding task have been made and two approaches have been introduced: globally multivariate random subsampling and locally multivariate Monte Carlo mapping. Both types of maps reflect voxel-wise decoding accuracies averaged across repeatedly randomly sampled voxel subsets, highlighting voxels which consistently participate in high-classification subsets. We compare the mapping sensitivities of the approaches on realistic simulated data containing both locally and globally multivariate information and demonstrate that utilizing the inherent volumetric nature of fMRI through clustered Monte Carlo mapping yields dramatically improved performances in terms of voxel detection sensitivity and efficiency. These results suggest that, unless a priori information specifically dictates a global search, variants of clustered sampling should be the priority for random subspace brain mapping.

  • 7.
    Björnsdotter Åberg, Malin
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Center for Social and Affective Neuroscience. Linköping University, Faculty of Medicine and Health Sciences. Karolinska Inst, Sweden.
    Davidovic, Monika
    Univ Gothenburg, Sweden.
    Karjalainen, Louise
    Univ Gothenburg, Sweden.
    Starck, Goran
    Univ Gothenburg, Sweden.
    Olausson, Håkan
    Linköping University, Department of Clinical and Experimental Medicine, Center for Social and Affective Neuroscience. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Clinical Neurophysiology. Univ Gothenburg, Sweden.
    Wentz, Elisabet
    Univ Gothenburg, Sweden; Sahlgrens Univ Hosp, Sweden.
    Grey matter correlates of autistic traits in women with anorexia nervosa2018In: Journal of Psychiatry & Neuroscience, ISSN 1180-4882, E-ISSN 1488-2434, Vol. 43, no 2, p. 79-86Article in journal (Refereed)
    Abstract [en]

    Background: Patients with anorexia nervosa exhibit higher levels of behaviours typically associated with autism-spectrum disorder (ASD), but the neural basis is unclear. We sought to determine whether elevated autistic traits in women with anorexia nervosa may be reflected in cortical morphology. Methods: We used voxel-based morphometry (VBM) to examine regional grey matter volumes in high-resolution MRI structural brain scans in women with anorexia nervosa and matched healthy controls. The Autism-spectrum Quotient (AQ) scale was used to assess autistic traits. Results: Women with anorexia nervosa (n = 25) had higher AQ scores and lower bilateral superior temporal sulcus (STS) grey matter volumes than the control group (n = 25). The AQ scores correlated negatively with average left STS grey matter volume in women with anorexia nervosa. Limitations: We did not control for cognitive ability and examined only women with ongoing anorexia nervosa. Conclusion: Elevated autistic traits in women with anorexia nervosa are associated with morphometric alterations of brain areas linked to social cognition. This finding provides neurobiological support for the behavioural link between anorexia nervosa and ASD and emphasizes the importance of recognizing autistic traits in preventing and treating-anorexia nervosa.

  • 8.
    Björnsdotter Åberg, Malin
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. University of Gothenburg, Sweden.
    Wang, Nancy
    Yale School Med, CT USA.
    Pelphrey, Kevin
    George Washington University, DC USA; Childrens National Medical Centre, DC 20010 USA.
    Kaiser, Martha D.
    Yale School Med, CT USA.
    Evaluation of Quantified Social Perception Circuit Activity as a Neurobiological Marker of Autism Spectrum Disorder2016In: JAMA psychiatry, ISSN 2168-6238, E-ISSN 2168-622X, Vol. 73, no 6, p. 614-621Article in journal (Refereed)
    Abstract [en]

    IMPORTANCE Autism spectrum disorder (ASD) is marked by social disability and is associated with dysfunction in brain circuits supporting social cue perception. The degree to which neural functioning reflects individual-level behavioral phenotype is unclear, slowing the search for functional neuroimaging biomarkers of ASD. OBJECTIVE To examine whether quantified neural function in social perception circuits may serve as an individual-level marker of ASD in children and adolescents. DESIGN, SETTING, AND PARTICIPANTS The cohort study was conducted at the Yale Child Study Center and involved children and adolescents diagnosed as having ASD and typically developing participants. Participants included a discovery cohort and a larger replication cohort. Individual-level social perception circuit functioning was assessed as functional magnetic resonance imaging brain responses to point-light displays of coherent vs scrambled human motion. MAIN OUTCOMES AND MEASURES Outcome measures included performance of quantified brain responses in affected male and female participants in terms of area under the receiver operating characteristic curve (AUC), sensitivity and specificity, and correlations between brain responses and social behavior. RESULTS Of the 39 participants in the discovery cohort aged 4 to 17 years, 22 had ASD and 30 were boys. Of the 75 participants in the replication cohort aged 7 to 20 years, 37 had ASD and 52 were boys. A relative reduction in social perception circuit responses was identified in discovery cohort boys with ASD at an AUC of 0.75 (95% CI, 0.52-0.89; P = .01); however, typically developing girls and girls with ASD could not be distinguished (P = .54). The results were confirmed in the replication cohort, where brain responses were identified in boys with ASD at an AUC of 0.79 (95% CI, 0.64-0.91; P amp;lt; .001) and failed to distinguish affected and unaffected girls (P = .82). Across both cohorts, boys were identified at an AUC of 0.77 (95% CI, 0.64-0.86) with corresponding sensitivity and specificity of 76% each. Additionally, brain responses were associated with social behavior in boys but not in girls. CONCLUSIONS AND RELEVANCE Quantified social perception circuit activity is a promising individual-level candidate neural marker of the male ASD behavioral phenotype. Our findings highlight the need to better understand effects of sex on social perception processing in relation to ASD phenotype manifestations.

  • 9.
    Davidovic, Monika
    et al.
    University of Gothenburg, Sweden.
    Jonsson, Emma H.
    University of Gothenburg, Sweden.
    Olausson, Håkan
    Linköping University, Center for Social and Affective Neuroscience (CSAN). Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Department of Clinical and Experimental Medicine.
    Björnsdotter Åberg, Malin
    Linköping University, Center for Social and Affective Neuroscience (CSAN). Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. University of Gothenburg, Sweden.
    Posterior Superior Temporal Sulcus Responses Predict Perceived Pleasantness of Skin Stroking2016In: Frontiers in Human Neuroscience, ISSN 1662-5161, E-ISSN 1662-5161, Vol. 10, no 432Article in journal (Refereed)
    Abstract [en]

    Love and affection is expressed through a range of physically intimate gestures, including caresses. Recent studies suggest that posterior temporal lobe areas typically associated with visual processing of social cues also respond to interpersonal touch. Here, we asked whether these areas are selective to caress-like skin stroking. We collected functional magnetic resonance imaging data from 23 healthy participants and compared brain responses to skin stroking and vibration. We did not find any significant differences between stroking and vibration in the posterior temporal lobe; however, right posterior superior temporal sulcus (pSTS) responses predicted healthy participants perceived pleasantness of skin stroking, but not vibration. These findings link right pSTS responses to individual variability in perceived pleasantness of caress-like tactile stimuli. We speculate that the right pSTS may play a role in the translation of tactile stimuli into positively valenced, socially relevant interpersonal touch and that this system may be affected in disorders associated with impaired attachment.

  • 10.
    Davidovic, Monika
    et al.
    Univ Gothenburg, Sweden.
    Karjalainen, Louise
    Univ Gothenburg, Sweden.
    Starck, Göran
    Univ Gothenburg, Sweden; Sahlgrens Univ Hosp, Sweden.
    Wentz, Elisabet
    Univ Gothenburg, Sweden.
    Björnsdotter Åberg, Malin
    Linköping University, Department of Clinical and Experimental Medicine, Center for Social and Affective Neuroscience. Linköping University, Faculty of Medicine and Health Sciences. Univ Gothenburg, Sweden.
    Olausson, Håkan
    Linköping University, Department of Clinical and Experimental Medicine, Center for Social and Affective Neuroscience. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Clinical Neurophysiology. Univ Gothenburg, Sweden.
    Abnormal brain processing of gentle touch in anorexia nervosa2018In: Psychiatry Research: Neuroimaging, ISSN 0925-4927, E-ISSN 1872-7506, Vol. 281, p. 53-60Article in journal (Refereed)
    Abstract [en]

    Body image disturbance is a core symptom in anorexia nervosa (AN). Recent research suggests that abnormalities in touch perception may contribute to the disease mechanisms in AN. Here, we used functional magnetic resonance imaging (fMRI) to study possible abnormalities in cortical processing of affective touch in AN. Gentle skin strokes were applied to the right forearm during fMRI scanning in women diagnosed with AN (n = 25) and in matched healthy controls (HC; n = 25). Blocks of skin stroking were alternated with blocks of static skin indentation. Participants provided ratings of the pleasantness of skin stroking stimulation. AN participants perceived skin stroking as significantly less pleasant than HC. We observed no group differences for the contrast between skin stroking and skin indentation in primary tactile regions. We did find, however, significantly less activity in the AN group in areas including left caudate nucleus. Also, we found less activity in the AN group in bilateral lateral occipital cortex for the main effect of skin stroking. Our results suggest that abnormal functioning of the dorsal striatum could affect evaluation of pleasant tactile stimuli, and that abnormal functioning of the lateral occipital cortex might be related to disturbed body image perception.

  • 11.
    Gentile, Giovanni
    et al.
    Karolinska Institute, Sweden.
    Åberg, Malin
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Karolinska Institute, Sweden.
    Petkova, Valeria I.
    Karolinska Institute, Sweden.
    Abdulkarim, Zakaryah
    Karolinska Institute, Sweden.
    Henrik Ehrsson, H.
    Karolinska Institute, Sweden.
    Patterns of neural activity in the human ventral premotor cortex reflect a whole-body multisensory percept2015In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 109, p. 328-340Article in journal (Refereed)
    Abstract [en]

    Previous research has shown that the integration of multisensory signals from the body in fronto-parietal association areas underlies the perception of a body part as belonging to ones physical self. What are the neural mechanisms that enable the perception of ones entire body as a unified entity? In one behavioral and one fMRI multivoxel pattern analysis experiment, we used a full-body illusion to investigate how congruent visuo-tactile signals from a single body part facilitate the emergence of the sense of ownership of the entire body. To elicit this illusion, participants viewed the body of a mannequin from the first-person perspective via head-mounted displays while synchronous touches were applied to the hand, abdomen, or leg of the bodies of the participant and the mannequin; asynchronous visuo-tactile stimuli served as controls. The psychometric data indicated that the participants perceived ownership of the entire artificial body regardless of the body segment that received the synchronous visuo-tactile stimuli. Based on multivoxel pattern analysis, we found that the neural responses in the left ventral premotor cortex displayed illusion-specific activity patterns that generalized across all tested pairs of body parts. Crucially, a tripartite generalization analysis revealed the whole-body specificity of these premotor activity patterns. Finally, we also identified multivoxel patterns in the premotor, intraparietal, and lateral occipital cortices and in the putamen that reflected multisensory responses specific to individual body parts. Based on these results, we propose that the dynamic formation of a whole-body percept may be mediated by neuronal populations in the ventral premotor cortex that contain visuo-tactile receptive fields encompassing multiple body segments.

  • 12.
    Guterstam, Arvid
    et al.
    Karolinska Institute, Sweden.
    Björnsdotter Åberg, Malin
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Karolinska Institute, Sweden.
    Bergouignan, Loretxu
    Karolinska Institute, Sweden; Basque Centre Cognit Brain and Language, Spain.
    Gentile, Giovanni
    Karolinska Institute, Sweden; CALTECH, CA 91125 USA.
    Li, Tie-Qiang
    Karolinska University, Sweden.
    Henrik Ehrsson, H.
    Karolinska Institute, Sweden.
    Decoding illusory self-location from activity in the human hippocampus2015In: Frontiers in Human Neuroscience, ISSN 1662-5161, E-ISSN 1662-5161, Vol. 9, no 412Article in journal (Refereed)
    Abstract [en]

    Decades of research have demonstrated a role for the hippocampus in spatial navigation and episodic and spatial memory. However, empirical evidence linking hippocampal activity to the perceptual experience of being physically located at a particular place in the environment is lacking. In this study, we used a multisensory out-of-body illusion to perceptually teleport six healthy participants between two different locations in the scanner room during high-resolution functional magnetic resonance imaging (fMRI). The participants were fitted with MRI-compatible head-mounted displays that changed their first-person visual perspective to that of a pair of cameras placed in one of two corners of the scanner room. To elicit the illusion of being physically located in this position, we delivered synchronous visuo-tactile stimulation in the form of an object moving toward the cameras coupled with touches applied to the participants chest. Asynchronous visuo-tactile stimulation did not induce the illusion and served as a control condition. We found that illusory self-location could be successfully decoded from patterns of activity in the hippocampus in all of the participants in the synchronous (P less than 0.05) but not in the asynchronous condition (Pgreater than 0.05). At the group-level, the decoding accuracy was significantly higher in the synchronous than in the asynchronous condition (P = 0.012). These findings associate hippocampal activity with the perceived location of the bodily self in space, which suggests that the human hippocampus is involved not only in spatial navigation and memory but also in the construction of our sense of bodily self-location.

  • 13.
    Guterstam, Arvid
    et al.
    Karolinska Institute, Sweden.
    Björnsdotter Åberg, Malin
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Karolinska Institute, Sweden.
    Gentile, Giovanni
    Karolinska Institute, Sweden.
    Ehrsson, H. Henrik
    Karolinska Institute, Sweden.
    Posterior Cingulate Cortex Integrates the Senses of Self-Location and Body Ownership2015In: Current Biology, ISSN 0960-9822, E-ISSN 1879-0445, Vol. 25, no 11, p. 1416-1425Article in journal (Refereed)
    Abstract [en]

    The senses of owning a body and being localized somewhere in space are two key components of human self-consciousness. Despite a wealth of neurophysiological and neuroimaging research on the representations of the spatial environment in the parietal and medial temporal cortices, the relationship between body ownership and self-location remains unexplored. To investigate this relationship, we used a multisensory out-of-body illusion to manipulate healthy participants perceived self-location, head direction, and sense of body ownership during high-resolution fMRI. Activity patterns in the hippocampus and the posterior cingulate, retrosplenial, and intraparietal cortices reflected the sense of self-location, whereas the sense of body ownership was associated with premotor-intraparietal activity. The functional interplay between these two sets of areas was mediated by the posterior cingulate cortex. These results extend our understanding of the role of the posterior parietal and medial temporal cortices in spatial cognition by demonstrating that these areas not only are important for ecological behaviors, such as navigation and perspective taking, but also support the perceptual representation of the bodily self in space. Our results further suggest that the posterior cingulate cortex has a key role in integrating the neural representations of self-location and body ownership.

  • 14.
    Liljencrantz, Jaquette
    et al.
    Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden.
    Björnsdotter, Malin
    Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden.
    Morrison, India
    Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden.
    Bergstrand, Simon
    Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden.
    Ceko, Marta
    Alan Edwards Centre for Research on Pain, McGill University, Montreal, Canada.
    Seminowicz, David A
    Alan Edwards Centre for Research on Pain, McGill University, Montreal, Canada.
    Cole, Jonathan
    Department of Clinical Neurophysiology, Poole Hospital and University of Bournemouth, Bournemouth, UK.
    Bushnell, Catherine M
    Alan Edwards Centre for Research on Pain, McGill University, Montreal, Canada.
    Olausson, Håkan
    Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden; Department of Integrative Physiology, School of Medicine, University of Western Sydney, Sydney, Australia.
    Altered C-tactile processing in human dynamic tactile allodynia.2013In: Pain, ISSN 0304-3959, E-ISSN 1872-6623, Vol. 154, no 2, p. 227-234Article in journal (Refereed)
    Abstract [en]

    Human unmyelinated (C) tactile afferents signal the pleasantness of gentle skin stroking on hairy (nonglabrous) skin. After neuronal injury, that same type of touch can elicit unpleasant sensations: tactile allodynia. The prevailing pathophysiological explanation is a spinal cord sensitization, triggered by nerve injury, which enables Aβ afferents to access pain pathways. However, a recent mouse knockout study demonstrates that C-tactile afferents are necessary for allodynia to develop, suggesting a role for not only Aβ but also C-tactile afferent signaling. To examine the contribution of C-tactile afferents to the allodynic condition in humans, we applied the heat/capsaicin model of tactile allodynia in 43 healthy subjects and in 2 sensory neuronopathy patients lacking Aβ afferents. Healthy subjects reported tactile-evoked pain, whereas the patients did not. Instead, patients reported their C-touch percept (faint sensation of pleasant touch) to be significantly weaker in the allodynic zone compared to untreated skin. Functional magnetic resonance imaging in 18 healthy subjects and in 1 scanned patient indicated that stroking in the allodynic and control zones evoked different responses in the primary cortical receiving area for thin fiber signaling, the posterior insular cortex. In addition, reduced activation in the medial prefrontal cortices, key areas for C-tactile hedonic processing, was identified. These findings suggest that dynamic tactile allodynia is associated with reduced C-tactile mediated hedonic touch processing. Nevertheless, because the patients did not develop allodynic pain, this seems dependent on Aβ signaling, at least under these experimental conditions.

  • 15.
    Morrison, India
    et al.
    Department of Clinical Neurophysiology, Sahlgrenska University Hospital, Gothenburg, Sweden; Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden.
    Björnsdotter, Malin
    Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden.
    Olausson, Håkan
    Department of Clinical Neurophysiology, Sahlgrenska University Hospital, Gothenburg, Sweden; Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden.
    Vicarious responses to social touch in posterior insular cortex are tuned to pleasant caressing speeds.2011In: Journal of Neuroscience, ISSN 0270-6474, E-ISSN 1529-2401, Vol. 31, no 26, p. 9554-9562Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Affective touch carries strong significance for social mammals, including humans. Gentle, dynamic touch of a kind that occurs during social interactions is preferentially encoded by a distinct neural pathway involving tactile C (CT) afferents, a type of unmyelinated afferent nerve found exclusively in hairy skin. CT afferents increase firing when the skin is stroked at a pleasant, caress-like speed of ∼3 cm/s, and their discharge frequency correlates with the subjective hedonic experience of the caress. In humans, the posterior insula is a cortical target for CT afferents. Since the potential social relevance of affective touch extends to the touch interactions of others, we postulated that information from CT afferents in posterior insular cortex provides a basis for encoding observed caresses.

    RESULTS: In two experiments, we exploited CT afferents' functionally unique tuning curve for stroking speed, demonstrating that a speed optimal for eliciting CT discharge (3 cm/s) also gives rise to higher BOLD responses in posterior insula than a nonoptimal speed (30 cm/s). When participants viewed videos of others' arms being stroked at CT-optimal versus -nonoptimal speeds, the posterior insula showed a similar response as to directly felt touch. Further, this region's response was specific for social interactions, showing no CT-related modulation for nonsocial dynamic-touch videos.

    CONCLUSIONS: These findings provide direct evidence for a functional relationship between CT signaling and processing in posterior insular cortex. Such selective tuning for CT-optimal signals in insula may allow recognition of the hedonic relevance of a merely observed caress.

  • 16.
    Petkova, Valeria I
    et al.
    Brain, Body & Self Laboratory, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
    Björnsdotter, Malin
    Brain, Body & Self Laboratory, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
    Gentile, Giovanni
    Brain, Body & Self Laboratory, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
    Jonsson, Tomas
    Department of Medical Physics, Karolinska University Hospital Huddinge, Stockholm, Sweden.
    Li, Tie-Qiang
    Department of Medical Physics, Karolinska University Hospital Huddinge, Stockholm, Sweden.
    Ehrsson, H Henrik
    Brain, Body & Self Laboratory, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
    From part- to whole-body ownership in the multisensory brain.2011In: Current Biology, ISSN 0960-9822, E-ISSN 1879-0445, Vol. 21, no 13, p. 1118-1122Article in journal (Refereed)
    Abstract [en]

    The question of how we experience ownership of an entire body distinct from the external world is a fundamental problem in psychology and neuroscience [1-6]. Earlier studies suggest that integration of visual, tactile, and proprioceptive information in multisensory areas [7-11] mediates self-attribution of single limbs. However, it is still unknown how ownership of individual body parts translates into the unitary experience of owning a whole body. Here, we used a "body-swap" illusion [12], in which people experienced an artificial body to be their own, in combination with functional magnetic resonance imaging to reveal a coupling between the experience of full-body ownership and neural responses in bilateral ventral premotor and left intraparietal cortices, and left putamen. Importantly, activity in the ventral premotor cortex reflected the construction of ownership of a whole body from the parts, because it was stronger when the stimulated body part was attached to a body, was present irrespective of whether the illusion was triggered by stimulation of the hand or the abdomen, and displayed multivoxel patterns carrying information about full-body ownership. These findings suggest that the unitary experience of owning an entire body is produced by neuronal populations that integrate multisensory information across body segments.

  • 17.
    Tuulari, Jetro J.
    et al.
    Univ Turku, Finland; Univ Turku, Finland; Univ Turku, Finland; Turku Univ Hosp, Finland.
    Scheinin, Noora M.
    Univ Turku, Finland; Univ Turku, Finland; Turku Univ Hosp, Finland.
    Lehtola, Satu
    Univ Turku, Finland.
    Merisaari, Harri
    Univ Turku, Finland; Univ Turku, Finland.
    Saunavaara, Jani
    Turku Univ Hosp, Finland.
    Parkkola, Riitta
    Turku Univ Hosp, Finland; Univ Turku, Finland.
    Sehlstedt, Isac
    Linköping University, Department of Clinical and Experimental Medicine, Center for Social and Affective Neuroscience. Linköping University, Faculty of Medicine and Health Sciences. Univ Gothenburg, Sweden.
    Karlsson, Linnea
    Univ Turku, Finland; Turku Univ Hosp, Finland; Univ Turku, Finland.
    Karlsson, Hasse
    Univ Turku, Finland; Univ Turku, Finland; Turku Univ Hosp, Finland.
    Björnsdotter Åberg, Malin
    Linköping University, Department of Clinical and Experimental Medicine, Center for Social and Affective Neuroscience. Linköping University, Faculty of Medicine and Health Sciences. Univ Gothenburg, Sweden.
    Neural correlates of gentle skin stroking in early infancy2019In: Developmental Cognitive Neuroscience, ISSN 1878-9293, E-ISSN 1878-9307, Vol. 35, p. 36-41Article in journal (Refereed)
    Abstract [en]

    Physical expressions of affection play a foundational role in early brain development, but the neural correlates of affective touch processing in infancy remain unclear. We examined brain responses to gentle skin stroking, a type of tactile stimulus associated with affectionate touch, in young infants. Thirteen term-born infants aged 11-36 days, recruited through the FinnBrain Birth Cohort Study, were included in the study. Soft brush strokes, which activate brain regions linked to somatosensory as well as socio-affective processing in children and adults, were applied to the skin of the right leg during functional magnetic resonance imaging. We examined infant brain responses in two regions-of-interest (ROIs) known to process gentle skin stroking - the postcentral gyrus and posterior insular cortex - and found significant responses in both ROIs. These results suggest that the neonate brain is responsive to gentle skin stroking within the first weeks of age, and that regions linked to primary somatosensory as well as socio-affective processing are activated. Our findings support the notion that social touch may play an important role in early life sensory processing. Future research will elucidate the significance of these findings for human brain development.

  • 18.
    Åberg, Malin B.
    et al.
    Institute of Neuroscience and Physiology, University of Gothenburg, Göteborg, Sweden.
    Wessberg, Johan
    Institute of Neuroscience and Physiology, University of Gothenburg, Göteborg, Sweden.
    An Evolutionary Approach to the Identification of Informative Voxel Clusters for Brain State Discrimination2008In: IEEE Journal on Selected Topics in Signal Processing, ISSN 1932-4553, E-ISSN 1941-0484, Vol. 2, no 6, p. 919-928Article in journal (Refereed)
    Abstract [en]

    We present a novel multivariate machine learning approach to the identification of voxel clusters containing brain state discriminating information, serving as a potentially more sensitive alternative to univariate activation detection. The proposed method consists of an evolutionary algorithm that, in conjunction with a classifier, extracts voxel clusters with a classification score above a pre-defined, above-chance threshold. The results can be displayed as two- or three-dimensional voxel discrimination relevance maps (VDRMs), indicating where and to what degree brain state classification is possible. When applied to a finger-tapping dataset numerous voxel clusters with impressive classification rates were identified, at best scoring an area under the receiver operating characteristic curve (ROC)-curve (AUC) of 1 within as well as between subjects. The location of high-scoring regions correlated well with functionally relevant areas as defined by the general linear model (GLM). Combining clusters for maximal classification scores as a feature selection approach outperformed the GLM T-map voxel ranking method (e.g., group level AUC of 0.908 compared to 0.785 for one cluster/200 voxels). Moreover, on data from a tactile study we show that the proposed algorithm can produce significant brain state discrimination scores where both the GLM and ROI-based classification fail to detect significantly activated voxels. Finally, we demonstrate that the algorithm can be successfully applied to data with more than two conditions and hence produce multiclass voxel relevance maps. The proposed evolutionary classification scheme has thus proven excellent in identifying voxel clusters that contain information about given brain states, which can be utilized not only for maximal single-volume fMRI classification, but also for multivariate, multiclass, highly sensitive functional brain mapping.

  • 19.
    Åberg, Malin C B
    et al.
    Department of Neuroscience and Physiology, Göteborg University.
    Wessberg, Johan
    Department of Neuroscience and Physiology, Göteborg University.
    Evolutionary optimization of classifiers and features for single-trial EEG discrimination.2007In: Biomedical engineering online, ISSN 1475-925X, E-ISSN 1475-925X, Vol. 6, no 32Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: State-of-the-art signal processing methods are known to detect information in single-trial event-related EEG data, a crucial aspect in development of real-time applications such as brain computer interfaces. This paper investigates one such novel approach, evaluating how individual classifier and feature subset tailoring affects classification of single-trial EEG finger movements. The discrete wavelet transform was used to extract signal features that were classified using linear regression and non-linear neural network models, which were trained and architecturally optimized with evolutionary algorithms. The input feature subsets were also allowed to evolve, thus performing feature selection in a wrapper fashion. Filter approaches were implemented as well by limiting the degree of optimization.

    RESULTS: Using only 10 features and 100 patterns, the non-linear wrapper approach achieved the highest validation classification accuracy (subject mean 75%), closely followed by the linear wrapper method (73.5%). The optimal features differed much between subjects, yet some physiologically plausible patterns were observed.

    CONCLUSION: High degrees of classifier parameter, structure and feature subset tailoring on individual levels substantially increase single-trial EEG classification rates, an important consideration in areas where highly accurate detection rates are essential. Also, the presented method provides insight into the spatial characteristics of finger movement EEG patterns.

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