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Kennis M, Dewitte M, T'Sjoen G, Stinkens K, Sack AT, Duecker F. The behavioral component of sexual inhibition and its relation with testosterone levels: An fMRI study in transgender and cisgender individuals. Psychoneuroendocrinology 2024; 163:106963. [PMID: 38342056 DOI: 10.1016/j.psyneuen.2024.106963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Revised: 11/22/2023] [Accepted: 01/11/2024] [Indexed: 02/13/2024]
Abstract
Many transgender individuals report having difficulties with initiating and seeking sexual contacts. Relatively to cisgender individuals, transgender individuals are more likely to avoid sexual activity, indicating that the groups might differ in the neural underpinnings of the behavioral component of sexual inhibition. In this fMRI study, transgender (n = 33) and cisgender (n = 34) participants performed an Approach Avoidance Task (AAT) assessing sexual inhibition. We found that over the entire sample, the task elicited brain activation commonly associated with general and sexual inhibition, for instance in the bilateral insula, right inferior parietal lobule, and right inferior and middle frontal gyri. Upon investigating group differences between transgender and cisgender participants, we mainly found similarities in neural activation during the task. However, there were group differences in regions involved in decision making processes (left middle temporal gyrus) and sexual response inhibition (right anterior cingulate cortex and left inferior parietal lobule). In order to investigate whether these group differences were modulated by testosterone levels, we performed ROI-analyses assessing the relationship between testosterone and neural activation during the AAT (controlling for sex assigned at birth), but no correlations were found. On the whole brain level, however, we found that testosterone correlated positively with cerebral activation in the right claustrum (a region associated with sexual arousal) during the approach of sexual stimuli in the transgender group. Overall, these findings indicate that transgender and cisgender individuals mostly show similarities in their neural response to a sexual Approach-Avoidance task, and that testosterone levels are unlikely to play an important role.
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Affiliation(s)
- M Kennis
- Maastricht University, Department of Cognitive Neuroscience, Maastricht, The Netherlands; Maastricht Brain Imaging Center, Maastricht, The Netherlands; Maastricht University, Department of Clinical Psychological Science, Maastricht, The Netherlands.
| | - M Dewitte
- Maastricht University, Department of Clinical Psychological Science, Maastricht, The Netherlands
| | - G T'Sjoen
- Ghent University Hospital, Department of Endocrinology, Ghent, Belgium; Ghent University Hospital, Center for Sexology and Gender, Ghent, Belgium
| | - K Stinkens
- Hospital Oost-Limburg, Department of Endocrinology, Genk, Belgium; Hospital Oost-Limburg, Gender Center, Genk, Belgium
| | - A T Sack
- Maastricht University, Department of Cognitive Neuroscience, Maastricht, The Netherlands; Maastricht Brain Imaging Center, Maastricht, The Netherlands; Maastricht University, Center for Integrative Neuroscience, Maastricht, The Netherlands
| | - F Duecker
- Maastricht University, Department of Cognitive Neuroscience, Maastricht, The Netherlands; Maastricht Brain Imaging Center, Maastricht, The Netherlands
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2
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Wang T, de Graaf T, Tanner L, Schuhmann T, Duecker F, Sack AT. Hemispheric Asymmetry in TMS-Induced Effects on Spatial Attention: A Meta-Analysis. Neuropsychol Rev 2023:10.1007/s11065-023-09614-2. [PMID: 37736863 DOI: 10.1007/s11065-023-09614-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 08/14/2023] [Indexed: 09/23/2023]
Abstract
Hemispheric asymmetry is a fundamental principle in the functional architecture of the brain. It plays an important role in attention research where right hemisphere dominance is core to many attention theories. Lesion studies seem to confirm such hemispheric dominance with patients being more likely to develop left hemineglect after right hemispheric stroke than vice versa. However, the underlying concept of hemispheric dominance is still not entirely clear. Brain stimulation studies using transcranial magnetic stimulation (TMS) might be able to illuminate this concept. To examine the putative hemispheric asymmetry in spatial attention, we conducted a meta-analysis of studies applying inhibitory TMS protocols to the left or right posterior parietal cortices (PPC), assessing effects on attention biases with the landmark and line bisection task. A total of 18 studies including 222 participants from 1994 to February 2022 were identified. The analysis revealed a significant shift of the perceived midpoint towards the ipsilateral hemifield after right PPC suppression (Cohen's d = 0.52), but no significant effect after left PPC suppression (Cohen's d = 0.26), suggesting a hemispheric asymmetry even though the subgroup difference does not reach significance (p = .06). A complementary Bayesian meta-analysis revealed a high probability of at least a medium effect size after right PPC disruption versus a low probability after left PPC disruption. This is the first quantitative meta-analysis supporting right hemisphere-specific TMS-induced spatial attention deficits, mimicking hemineglect in healthy participants. We discuss the result in the light of prominent attention theories, ultimately concluding how difficult it remains to differentiate between these theories based on attentional bias scores alone.
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Affiliation(s)
- Ting Wang
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, 6200 MD, Maastricht, the Netherlands.
- Maastricht Brain Imaging Centre, Maastricht, the Netherlands.
| | - Tom de Graaf
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, 6200 MD, Maastricht, the Netherlands
- Maastricht Brain Imaging Centre, Maastricht, the Netherlands
| | - Lisabel Tanner
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, 6200 MD, Maastricht, the Netherlands
| | - Teresa Schuhmann
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, 6200 MD, Maastricht, the Netherlands
- Maastricht Brain Imaging Centre, Maastricht, the Netherlands
| | - Felix Duecker
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, 6200 MD, Maastricht, the Netherlands
- Maastricht Brain Imaging Centre, Maastricht, the Netherlands
| | - Alexander T Sack
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, 6200 MD, Maastricht, the Netherlands
- Maastricht Brain Imaging Centre, Maastricht, the Netherlands
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University Medical Centre+, Brain+Nerve Centre, Maastricht, the Netherlands
- Centre for Integrative Neuroscience, Faculty of Psychology and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, the Netherlands
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Kennis M, Duecker F, Elaut E, T'Sjoen G, Loeys T, Sack AT, Dewitte M. Daily Sexual Behavior, Sexual Esteem, and Body Image in Transgender and Cisgender Individuals. J Sex Res 2022:1-9. [PMID: 36548099 DOI: 10.1080/00224499.2022.2158172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Multiple surveys have suggested that transgender individuals show lower sexual well-being than cisgender individuals. Most studies, however, are limited in terms of ecological validity and memory bias and cross-sectional in nature. These issues are less prevalent in diary studies monitoring responses over time at home. For three weeks, 47 transgender (M age = 29.00, SD = 11.62) and 52 cisgender individuals (M age = 32.90, SD = 11.44) reported daily on their sexual behavior, sexual esteem and body image. Using multilevel model analyses, we investigated the daily associations between these variables, and addressed differences between transgender and cisgender individuals. We found that in transgender individuals, intimacy predicted sexual esteem; sexual openness predicted sexual esteem and body image; and sexual esteem predicts intimacy, masturbation, and sexual openness on the daily level. While transgender individuals scored lower on daily sexual esteem and body image than cisgender individuals, groups did not differ in daily sexual behavior. They also did not differ in any of the predictive relations described above, but we did find that the association between masturbation and body image was moderated by a cisgender identity, and sexual esteem predicted sexual activity more positively in cisgender compared to transgender individuals. These results complement findings from cross-sectional studies and indicate how transgender individuals struggling with sexuality can increase sexual openness. Implications for clinical practice are that clinicians discussing sexuality with their transgender patients should not define sexual activity too narrowly, and that sexual esteem might be a relevant factor in determining sexual behavior.
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Affiliation(s)
- Mathilde Kennis
- Department of Clinical Psychological Science, Maastricht University, Maastricht, Netherlands
- Department of Cognitive Neuroscience, Maastricht University, Maastricht, Netherlands
- Maastricht Brain Imaging Center, Maastricht, Netherlands
| | - Felix Duecker
- Department of Cognitive Neuroscience, Maastricht University, Maastricht, Netherlands
- Maastricht Brain Imaging Center, Maastricht, Netherlands
| | - Els Elaut
- Department of Clinical-Experimental and Health Psychology, Ghent University, Ghent, Belgium
- Center for Sexology and Gender, Ghent University Hospital, Ghent, Belgium
| | - Guy T'Sjoen
- Center for Sexology and Gender, Ghent University Hospital, Ghent, Belgium
- Department of Endocrinology, Ghent University Hospital, Ghent, Belgium
| | - Tom Loeys
- Department of Data Analysis, Ghent University, Ghent, Belgium
| | - Alexander T Sack
- Department of Cognitive Neuroscience, Maastricht University, Maastricht, Netherlands
- Maastricht Brain Imaging Center, Maastricht, Netherlands
- Center for Integrative Neuroscience, Maastricht University, Maastricht, Netherlands
| | - Marieke Dewitte
- Department of Clinical Psychological Science, Maastricht University, Maastricht, Netherlands
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Middag‐van Spanje M, Duecker F, Gallotto S, de Graaf TA, van Heugten C, Sack AT, Schuhmann T. Transcranial magnetic stimulation over posterior parietal cortex modulates alerting and executive control processes in attention. Eur J Neurosci 2022; 56:5853-5868. [PMID: 36161393 PMCID: PMC9828423 DOI: 10.1111/ejn.15830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 09/14/2022] [Indexed: 01/12/2023]
Abstract
Attention includes three different functional components: generating and maintaining an alert state (alerting), orienting to sensory events (orienting), and resolving conflicts between alternative actions (executive control). Neuroimaging and patient studies suggest that the posterior parietal cortex (PPC) is involved in all three attention components. Transcranial magnetic stimulation (TMS) has repeatedly been applied over the PPC to study its functional role for shifts and maintenance of visuospatial attention. Most TMS-PPC studies used only detection tasks or orienting paradigms to investigate TMS-PPC effects on attention processes, neglecting the alerting and executive control components of attention. The objective of the present study was to investigate the role of PPC in all three functional components of attention: alerting, orienting, and executive control. To this end, we disrupted PPC with TMS (continuous theta-burst stimulation), to modulate subsequent performance on the Lateralized-Attention Network Test, used to assess the three attention components separately. Our results revealed hemifield-specific effects on alerting and executive control functions, but we did not find stimulation effects on orienting performance. While this field of research and associated clinical development have been predominantly focused on orienting performance, our results suggest that parietal cortex and its modulation may affect other aspects of attention as well.
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Affiliation(s)
- Marij Middag‐van Spanje
- Department of Cognitive Neuroscience, Faculty of Psychology and NeuroscienceMaastricht UniversityMaastrichtThe Netherlands,InteraktContourNunspeetThe Netherlands
| | - Felix Duecker
- Department of Cognitive Neuroscience, Faculty of Psychology and NeuroscienceMaastricht UniversityMaastrichtThe Netherlands,Maastricht Brain Imaging CenterMaastrichtThe Netherlands
| | - Stefano Gallotto
- Department of Cognitive Neuroscience, Faculty of Psychology and NeuroscienceMaastricht UniversityMaastrichtThe Netherlands
| | - Tom A. de Graaf
- Department of Cognitive Neuroscience, Faculty of Psychology and NeuroscienceMaastricht UniversityMaastrichtThe Netherlands,Maastricht Brain Imaging CenterMaastrichtThe Netherlands
| | - Caroline van Heugten
- Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and NeuroscienceMaastricht UniversityMaastrichtThe Netherlands,Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Brain + Nerve CentreMaastricht University Medical Centre+MaastrichtThe Netherlands,Limburg Brain Injury CenterMaastrichtThe Netherlands
| | - Alexander T. Sack
- Department of Cognitive Neuroscience, Faculty of Psychology and NeuroscienceMaastricht UniversityMaastrichtThe Netherlands,Maastricht Brain Imaging CenterMaastrichtThe Netherlands,Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Brain + Nerve CentreMaastricht University Medical Centre+MaastrichtThe Netherlands
| | - Teresa Schuhmann
- Department of Cognitive Neuroscience, Faculty of Psychology and NeuroscienceMaastricht UniversityMaastrichtThe Netherlands,Maastricht Brain Imaging CenterMaastrichtThe Netherlands
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5
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Schuhmann T, Duecker F, Middag-van Spanje M, Gallotto S, van Heugten C, Schrijnemaekers AC, van Oostenbrugge R, Sack AT. Transcranial alternating brain stimulation at alpha frequency reduces hemispatial neglect symptoms in stroke patients. Int J Clin Health Psychol 2022; 22:100326. [PMID: 35990733 PMCID: PMC9364103 DOI: 10.1016/j.ijchp.2022.100326] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 07/18/2022] [Indexed: 12/03/2022] Open
Abstract
Background/Objective Non-invasive brain stimulation techniques such as transcranial alternating current stimulation (tACS) may help alleviate attention deficits in stroke patients with hemispatial neglect by modulating oscillatory brain activity. We applied high-definition (HD)-tACS at alpha frequency over the contralesional hemisphere to support unilateral oscillatory alpha activity and correct for the pathologically altered attention bias in neglect patients. Methods We performed a within-subject, placebo-controlled study in which sixteen stroke patients with hemispatial neglect underwent 10 Hz (alpha) as well as sham (placebo) stimulation targeting the contralesional posterior parietal cortex. Attentional bias was measured with a computerized visual detection paradigm and two standard paper-and-pencil neglect tests. Results We revealed a significant shift of attentional resources after alpha-HD-tACS, but not sham tACS, toward the ipsilateral and thus contralesional hemifield leading to a reduction in neglect symptoms, measured with a computerized visual detection paradigm and a widely used standard paper and pencil neglect tests. Conclusions We showed a significant alpha-HD-tACS-induced shift of attentional resources toward the contralesional hemifield, thus leading to a reduction in neglect symptoms. Importantly, HD-tACS effects persisted after the stimulation itself had ended. This tACS protocol, based on intrinsic oscillatory processes, may be an effective and well-tolerated treatment option for neglect.
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Affiliation(s)
- Teresa Schuhmann
- Section Brain Stimulation and Cognition, Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, the Netherlands.,Maastricht Brain Imaging Centre (MBIC), Maastricht University, Maastricht, the Netherlands
| | - Felix Duecker
- Section Brain Stimulation and Cognition, Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, the Netherlands.,Maastricht Brain Imaging Centre (MBIC), Maastricht University, Maastricht, the Netherlands
| | - Marij Middag-van Spanje
- Section Brain Stimulation and Cognition, Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, the Netherlands.,Maastricht Brain Imaging Centre (MBIC), Maastricht University, Maastricht, the Netherlands.,InteraktContour, Nunspeet, the Netherlands
| | - Stefano Gallotto
- Section Brain Stimulation and Cognition, Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, the Netherlands.,Maastricht Brain Imaging Centre (MBIC), Maastricht University, Maastricht, the Netherlands.,EEG and Epilepsy Unit, University Hospitals and Faculty of Medicine of Geneva, University of Geneva, Geneva, Switzerland
| | - Caroline van Heugten
- Limburg Brain Injury Center, the Netherlands.,Department of Neuropsychology & Psychopharmacology, Faculty of Psychology and Neuroscience (FPN), Maastricht University, the Netherlands.,School for Mental Health and Neuroscience, Department of Psychiatry & Neuropsychology, Faculty of Health, Medicine and Life Sciences (FHML), Maastricht University Medical Center, the Netherlands
| | - Anne-Claire Schrijnemaekers
- Adelante Rehabilitation Centre, Department of Brain Injury, Hoensbroek, the Netherlands.,Mondriaan Mental Health Centre, Department of Adult Psychiatry, Heerlen, the Netherlands
| | - Robert van Oostenbrugge
- Department of Neurology, School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Alexander T Sack
- Section Brain Stimulation and Cognition, Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, the Netherlands.,Maastricht Brain Imaging Centre (MBIC), Maastricht University, Maastricht, the Netherlands.,Centre for Integrative Neuroscience, Faculty of Psychology and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, the Netherlands
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6
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Kennis M, Duecker F, T'Sjoen G, Sack AT, Dewitte M. Gender Affirming Medical Treatment Desire and Treatment Motives in Binary and Non-Binary Transgender Individuals. J Sex Med 2022; 19:1173-1184. [PMID: 35418328 DOI: 10.1016/j.jsxm.2022.03.603] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 03/11/2022] [Accepted: 03/14/2022] [Indexed: 01/07/2023]
Abstract
BACKGROUND It is currently unknown whether there are differences in desire for gender affirming medical treatment (GAMT) between binary and non-binary transgender individuals, although the latter seek treatment less prevalently. AIM To investigate differences between binary and non-binary individuals on received GAMT, desire for GAMT, and motives for (not) wanting GAMT, and to explore the association between having an unfulfilled treatment desire and general and sexual well-being. METHODS We conducted an online questionnaire in a community sample of 125 transgender men, 72 transgender women, and 62 non-binary transgender individuals (age: M = 30.4, SD = 11.31, range 18-69). OUTCOME MEASURES Undergone GAMT, GAMT desire, motives for (not) wanting (further) GAMT, Utrecht Gender Dysphoria Scale, Satisfaction With Life Scale, Hospital Anxiety and Depression Scale, Global Measure of Sexual Satisfaction, transgender-specific body image worries, and sexual self-concept discrepancies. RESULTS Binary transgender participants reported having undergone more GAMT procedures than non-binary transgender participants (P < .001 for both gender affirming hormone treatment (GAHT) and gender affirming surgery (GAS)). While binary participants reported a stronger desire for GAHT compared to non-binary participants (X2(1, N = 93) = 32.63, P < .001), the groups did not differ in their desire for GAS (X2(1, N = 247) = 0.68, P = .411). Binary and non-binary participants reported similar reasons for wanting treatment, mostly related to body and/or gender incongruence and gender affirmation. In terms of not wanting treatment, the non-binary group reported their gender identity as the most important reason, while the binary group mostly mentioned possible medical complications. The majority of both groups had an unfulfilled treatment desire (69% of binary participants and 64.5% of non-binary participants), which was related to lower levels of general life satisfaction (P < .001) and sexual satisfaction (P = .005), more anxiety (P = .006) and transgender-specific body image worries (P < .001), and larger sexual self-concept discrepancies (P < .001 for actual and/or ideal, P < .001 for actual and/or ought). CLINICAL IMPLICATIONS Systemic barriers to GAMT (especially GAS) should be removed not only for binary but also for non-binary identifying transgender individuals to decrease the discrepancy between treatment desire and actually seeking treatment. STRENGTHS & LIMITATIONS This study was the first to systematically investigate differences in treatment desire motives between binary and non-binary transgender individuals, while also showing the possible negative consequences of an unfulfilled treatment desire. Given the online character of the study, results may not generalize to the broader transgender community. CONCLUSION Similarly to binary transgender individuals, many non-binary transgender individuals have a desire for GAMT, and not being able to receive GAMT has a negative effect on their mental and sexual health. Further efforts should be made to make GAMT accessible for all transgender individuals, regardless of gender identity. Kennis M, Duecker F, T'Sjoen G, et al. Gender Affirming Medical Treatment Desire and Treatment Motives in Binary and Non-Binary Transgender Individuals. J Sex Med 2022;19:1173-1184.
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Affiliation(s)
- Mathilde Kennis
- Maastricht University, Department of Clinical Psychological Science, Maastricht, The Netherlands; Maastricht University, Department of Cognitive Neuroscience, Maastricht, The Netherlands; Maastricht Brain Imaging Center, Maastricht, The Netherlands.
| | - Felix Duecker
- Maastricht University, Department of Cognitive Neuroscience, Maastricht, The Netherlands; Maastricht Brain Imaging Center, Maastricht, The Netherlands
| | - Guy T'Sjoen
- Ghent University Hospital, Department of Endocrinology, Ghent, Belgium; Ghent University Hospital, Center for Sexology and Gender, Ghent, Belgium
| | - Alexander T Sack
- Maastricht University, Department of Cognitive Neuroscience, Maastricht, The Netherlands; Maastricht Brain Imaging Center, Maastricht, The Netherlands; Maastricht University, Department of Psychiatry and Neuropsychology, Maastricht, The Netherlands; Maastricht University, Center for Integrative Neuroscience, Maastricht, The Netherlands
| | - Marieke Dewitte
- Maastricht University, Department of Clinical Psychological Science, Maastricht, The Netherlands
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Kennis M, Duecker F, T'Sjoen G, Sack AT, Dewitte M. Sexual Self-Concept Discrepancies Mediate the Relation between Gender Dysphoria Sexual Esteem and Sexual Attitudes in Binary Transgender Individuals. J Sex Res 2022; 59:524-536. [PMID: 34279141 DOI: 10.1080/00224499.2021.1951643] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Sexual responding in transgender people has typically been investigated from a medical and functional perspective. Aligning with the biopsychosocial model, it is however equally important to consider psychological aspects of sexuality in this population. We propose that the Sexual Self-Concept (SSC) theory offers a valuable framework to understand (sexual) wellbeing in transgender people, while Self-Concept Discrepancy (SCD) theory could offer an explanation of the mechanisms underlying negative SSCs related to gender dysphoria. We investigated differences in SSC (consisting of sexual esteem, sexual attitudes, and sexual self-efficacy) in 197 binary transgender and 205 cisgender individuals using an online survey and explored the mediating role of actual/ideal self-discrepancies in explaining the relation between gender dysphoria and SSC. Transgender and cisgender individuals differed significantly in seven out of eight components related to sexual esteem and sexual attitudes. Actual/ideal self-discrepancies mediated the relationship between gender dysphoria and the SSC in transgender individuals for the sexual esteem components related to body perception, conduct, and attractiveness, as well as for sexual anxiety. We found no relation between gender dysphoria and the other SSC components in this group. We conclude that SSC discrepancies could be a valuable treatment target to improve transgender individuals' sexual esteem and sexual attitudes.
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Affiliation(s)
- Mathilde Kennis
- Department of Clinical Psychological Science, Maastricht University
- Department of Cognitive Neuroscience, Maastricht University
- Maastricht Brain Imaging Center, Maastricht University
| | - Felix Duecker
- Department of Cognitive Neuroscience, Maastricht University
- Maastricht Brain Imaging Center, Maastricht University
| | - Guy T'Sjoen
- Department of Endocrinology, Ghent University Hospital
- Center for Sexology and Gender, Ghent University Hospital
| | - Alexander T Sack
- Department of Cognitive Neuroscience, Maastricht University
- Maastricht Brain Imaging Center, Maastricht University
- Department of Psychiatry and Neuropsychology, Maastricht University
- Center for Integrative Neuroscience, Maastricht University
| | - Marieke Dewitte
- Department of Clinical Psychological Science, Maastricht University
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Dionísio A, Gouveia R, Castelhano J, Duarte IC, Santo GC, Sargento-Freitas J, Duecker F, Castelo-Branco M. The Role of Continuous Theta Burst TMS in the Neurorehabilitation of Subacute Stroke Patients: A Placebo-Controlled Study. Front Neurol 2021; 12:749798. [PMID: 34803887 PMCID: PMC8599133 DOI: 10.3389/fneur.2021.749798] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 09/30/2021] [Indexed: 11/13/2022] Open
Abstract
Objectives: Transcranial magnetic stimulation, in particular continuous theta burst (cTBS), has been proposed for stroke rehabilitation, based on the concept that inhibition of the healthy hemisphere helps promote the recovery of the lesioned one. We aimed to study its effects on cortical excitability, oscillatory patterns, and motor function, the main aim being to identify potentially beneficial neurophysiological effects. Materials and Methods: We applied randomized real or placebo stimulation over the unaffected primary motor cortex of 10 subacute (7 ± 3 days) post-stroke patients. Neurophysiological measurements were performed using electroencephalography and electromyography. Motor function was assessed with the Wolf Motor Function Test. We performed a repeated measure study with the recordings taken pre-, post-cTBS, and at 3 months' follow-up. Results: We investigated changes in motor rhythms during arm elevation and thumb opposition tasks and found significant changes in beta power of the affected thumb's opposition, specifically after real cTBS. Our results are consistent with an excitatory response (increase in event-related desynchronization) in the sensorimotor cortical areas of the affected hemisphere, after stimulation. Neither peak-to-peak amplitude of motor-evoked potentials nor motor performance were significantly altered. Conclusions: Consistently with the theoretical prediction, this contralateral inhibitory stimulation paradigm changes neurophysiology, leading to a significant excitatory impact on the cortical oscillatory patterns of the contralateral hemisphere. These proof-of-concept results provide evidence for the potential role of continuous TBS in the neurorehabilitation of post-stroke patients. We suggest that these changes in ERS/ERD patterns should be further explored in future phase IIb/phase III clinical trials, in larger samples of poststroke patients.
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Affiliation(s)
- Ana Dionísio
- Institute of Nuclear Sciences Applied to Health ICNAS, Coimbra Institute for Biomedical Imaging and Translational Research CIBIT, University of Coimbra, Coimbra, Portugal.,Faculty of Sciences and Technology FCTUC, Department of Physics, University of Coimbra, Coimbra, Portugal.,Faculty of Medicine FMUC, University of Coimbra, Coimbra, Portugal
| | - Rita Gouveia
- Institute of Nuclear Sciences Applied to Health ICNAS, Coimbra Institute for Biomedical Imaging and Translational Research CIBIT, University of Coimbra, Coimbra, Portugal
| | - João Castelhano
- Institute of Nuclear Sciences Applied to Health ICNAS, Coimbra Institute for Biomedical Imaging and Translational Research CIBIT, University of Coimbra, Coimbra, Portugal.,Faculty of Medicine FMUC, University of Coimbra, Coimbra, Portugal
| | - Isabel Catarina Duarte
- Institute of Nuclear Sciences Applied to Health ICNAS, Coimbra Institute for Biomedical Imaging and Translational Research CIBIT, University of Coimbra, Coimbra, Portugal.,Faculty of Medicine FMUC, University of Coimbra, Coimbra, Portugal
| | - Gustavo C Santo
- Stroke Unit, Neurology Department, Coimbra Hospital and University Centre, Coimbra, Portugal
| | - João Sargento-Freitas
- Stroke Unit, Neurology Department, Coimbra Hospital and University Centre, Coimbra, Portugal
| | - Felix Duecker
- Institute of Nuclear Sciences Applied to Health ICNAS, Coimbra Institute for Biomedical Imaging and Translational Research CIBIT, University of Coimbra, Coimbra, Portugal.,Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands.,Maastricht Brain Imaging Center, Maastricht University, Maastricht, Netherlands
| | - Miguel Castelo-Branco
- Institute of Nuclear Sciences Applied to Health ICNAS, Coimbra Institute for Biomedical Imaging and Translational Research CIBIT, University of Coimbra, Coimbra, Portugal.,Faculty of Medicine FMUC, University of Coimbra, Coimbra, Portugal.,Maastricht Brain Imaging Center, Maastricht University, Maastricht, Netherlands.,Brain Imaging Network, University of Coimbra, Coimbra, Portugal
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9
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Kennis M, Duecker F, T’Sjoen G, Sack AT, Dewitte M. Mental and sexual well-being in non-binary and genderqueer individuals. Int J Transgend Health 2021; 23:442-457. [PMID: 36324878 PMCID: PMC9621256 DOI: 10.1080/26895269.2021.1995801] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
BACKGROUND Non-binary and genderqueer (NBGQ) individuals do not identify with a binary gender identity. Some but not all NBGQ individuals identify as transgender, and it is currently unclear on which aspects of mental and sexual well-being NBGQ and binary transgender individuals may differ. AIM To compare NBGQ, binary transgender and cisgender individuals on variables related to mental well-being, sexual well-being, and sexual self-concept discrepancies. METHODS We conducted an online questionnaire study in 125 transgender men, 72 transgender women, 78 NBGQ individuals, 98 cisgender men, and 107 cisgender women. RESULTS For most variables, NBGQ individuals did not differ from binary transgender individuals. These two groups differed only on gender dysphoria and transgender specific body image worries, which were both lower in the NBGQ group. Compared to the cisgender group, NBGQ individuals scored higher on gender dysphoria, actual/ought sexual self-concept discrepancies, and actual/ideal sexual self-concept discrepancies, and lower on general life satisfaction and sexual esteem related to body perception. DISCUSSION These results offer a first quantitative analysis of sexual well-being in NBGQ individuals, and highlight that - while both groups face unique challenges - NBGQ individuals encounter similar difficulties concerning mental and sexual well-being as binary transgender individuals.
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Affiliation(s)
- Mathilde Kennis
- Department of Clinical Psychological Science, Maastricht University, Maastricht, Netherlands
- Department of Cognitive Neuroscience, Maastricht University, Maastricht, Netherlands
- Maastricht Brain Imaging Center, Maastricht, Netherlands
| | - Felix Duecker
- Department of Cognitive Neuroscience, Maastricht University, Maastricht, Netherlands
- Maastricht Brain Imaging Center, Maastricht, Netherlands
| | - Guy T’Sjoen
- Department of Endocrinology, Ghent University Hospital, Ghent, Belgium
- Center for Sexology and Gender, Ghent University Hospital, Ghent, Belgium
| | - Alexander T. Sack
- Department of Cognitive Neuroscience, Maastricht University, Maastricht, Netherlands
- Maastricht Brain Imaging Center, Maastricht, Netherlands
- Department of Psychiatry and Neuropsychology, Maastricht, Netherlands
- Center for Integrative Neuroscience, Maastricht University, Maastricht, Netherlands
| | - Marieke Dewitte
- Department of Clinical Psychological Science, Maastricht University, Maastricht, Netherlands
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de Graaf TA, Duecker F. No effects of rhythmic visual stimulation on target discrimination: An online alpha entrainment experiment. Eur J Neurosci 2021; 55:3340-3351. [PMID: 34592020 PMCID: PMC9542333 DOI: 10.1111/ejn.15483] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 09/08/2021] [Accepted: 09/17/2021] [Indexed: 01/08/2023]
Abstract
Previous research established that rhythmic sensory stimulation can affect subsequent stimulus perception, possibly through 'entrainment' of oscillations in the brain. Alpha frequency is a natural target for visual entrainment, because fluctuations in posterior alpha oscillations have been linked to visual target detection or discrimination. On the other hand, alpha oscillations also relate to attentional mechanisms, such as attentional orienting or selection. Previous visual alpha entrainment studies focused on differential processing of targets presented in-phase with the preceding rhythmic stimulation relative to out-of-phase targets (an 'SOA effect'), putatively related to the phase of entrained neuronal alpha oscillations. Fewer studies probed the consequences of rhythmic alpha stimulation for attention mechanisms related to alpha power. Here, we asked whether alpha stimulation of one hemifield has similar effects on reaction times as we see for increased alpha synchronization in magneto/electroencephalography (M/EEG) studies (i.e., more alpha means impaired processing and functional inhibition). We implemented a task inspired by attention studies, assessing reaction times to ipsilateral vs. contralateral visual targets, with and without concurrent presentation of distractors. Yet, in place of any attention cues, we presented a rhythmic, vs. arrhythmic, alpha-frequency train of visual flashes to one hemifield, in a large sample size (N = 115) in an online experiment. We found clear evidence that flash train rhythmicity did not impact task performance. We also found that the spatial congruence between the unilateral flash train and the subsequent visual target did impact response times but only in the presence of contralateral distractor stimuli. We discuss implications, limitations and future directions.
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Affiliation(s)
- Tom A de Graaf
- Brain Stimulation and Cognition Section, Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands.,Maastricht Brain Imaging Centre (MBIC), Maastricht University, Maastricht, The Netherlands.,Center for Integrative Neuroscience (CIN), Maastricht University, Maastricht, The Netherlands
| | - Felix Duecker
- Brain Stimulation and Cognition Section, Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands.,Maastricht Brain Imaging Centre (MBIC), Maastricht University, Maastricht, The Netherlands
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11
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Veniero D, Gross J, Morand S, Duecker F, Sack AT, Thut G. Top-down control of visual cortex by the frontal eye fields through oscillatory realignment. Nat Commun 2021; 12:1757. [PMID: 33741947 PMCID: PMC7979788 DOI: 10.1038/s41467-021-21979-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 02/19/2021] [Indexed: 11/09/2022] Open
Abstract
Voluntary allocation of visual attention is controlled by top-down signals generated within the Frontal Eye Fields (FEFs) that can change the excitability of lower-level visual areas. However, the mechanism through which this control is achieved remains elusive. Here, we emulated the generation of an attentional signal using single-pulse transcranial magnetic stimulation to activate the FEFs and tracked its consequences over the visual cortex. First, we documented changes to brain oscillations using electroencephalography and found evidence for a phase reset over occipital sites at beta frequency. We then probed for perceptual consequences of this top-down triggered phase reset and assessed its anatomical specificity. We show that FEF activation leads to cyclic modulation of visual perception and extrastriate but not primary visual cortex excitability, again at beta frequency. We conclude that top-down signals originating in FEF causally shape visual cortex activity and perception through mechanisms of oscillatory realignment.
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Affiliation(s)
| | - Joachim Gross
- Institute for Biomagnetism and Biosignalanalysis, University of Münster, Münster, Germany
| | | | - Felix Duecker
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Alexander T Sack
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Gregor Thut
- Centre for Cognitive Neuroimaging, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow, UK
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Ten Oever S, Meierdierks T, Duecker F, De Graaf TA, Sack AT. Phase-Coded Oscillatory Ordering Promotes the Separation of Closely Matched Representations to Optimize Perceptual Discrimination. iScience 2020; 23:101282. [PMID: 32604063 PMCID: PMC7326734 DOI: 10.1016/j.isci.2020.101282] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 05/12/2020] [Accepted: 06/12/2020] [Indexed: 11/15/2022] Open
Abstract
Low-frequency oscillations are proposed to be involved in separating neuronal representations belonging to different items. Although item-specific neuronal activity was found to cluster on different oscillatory phases, the influence of this mechanism on perception is unknown. Here, we investigated the perceptual consequences of neuronal item separation through oscillatory clustering. In an electroencephalographic experiment, participants categorized sounds parametrically varying in pitch, relative to an arbitrary pitch boundary. Pre-stimulus theta and alpha phase biased near-boundary sound categorization to one category or the other. Phase also modulated whether evoked neuronal responses contributed stronger to the fit of the sound envelope of one or another category. Intriguingly, participants with stronger oscillatory clustering (phase strongly biasing sound categorization) in the theta, but not alpha, range had steeper perceptual psychometric slopes (sharper sound category discrimination). These results indicate that neuronal sorting by phase directly influences subsequent perception and has a positive impact on discrimination performance. Pre-stimulus theta/alpha phase co-determines how we perceive ambiguous sounds Phase influences to which sound envelope evoked potentials fit better Neural separation through phase clustering promotes sound discrimination
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Affiliation(s)
- Sanne Ten Oever
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, P.O. Box 616, 6200 MD Maastricht, the Netherlands; Max Planck Institute for Psycholinguistics, P.O. Box 310, 6500 AH Nijmegen, the Netherlands; Donders Centre for Cognitive Neuroimaging, P.O. Box 9010, 6500 GL Nijmegen, The Netherlands.
| | - Tobias Meierdierks
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, P.O. Box 616, 6200 MD Maastricht, the Netherlands
| | - Felix Duecker
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, P.O. Box 616, 6200 MD Maastricht, the Netherlands; Maastricht Brain Imaging Centre, 6229 EV Maastricht, the Netherlands
| | - Tom A De Graaf
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, P.O. Box 616, 6200 MD Maastricht, the Netherlands; Maastricht Brain Imaging Centre, 6229 EV Maastricht, the Netherlands
| | - Alexander T Sack
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, P.O. Box 616, 6200 MD Maastricht, the Netherlands; Maastricht Brain Imaging Centre, 6229 EV Maastricht, the Netherlands; Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNs), Brain and Nerve Centre, Maastricht University Medical Centre+ (MUMC+), Maastricht, the Netherlands
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13
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Dionísio A, Gouveia R, Duarte IC, Castelhano J, Duecker F, Castelo-Branco M. Continuous theta burst stimulation increases contralateral mu and beta rhythms with arm elevation: implications for neurorehabilitation. J Neural Transm (Vienna) 2019; 127:17-25. [PMID: 31844983 DOI: 10.1007/s00702-019-02117-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Accepted: 12/07/2019] [Indexed: 11/24/2022]
Abstract
The study of the physiological effects underlying brain response to transcranial magnetic stimulation is important to understand its impact on neurorehabilitation. We aim to analyze the impact of a transcranial magnetic stimulation protocol, the continuous theta burst (cTBS), on human neurophysiology, particularly on contralateral motor rhythms. cTBS was applied in 20 subjects over the primary motor cortex. We recorded brain electrical activity pre- and post-cTBS with electroencephalography both at rest and while performing motor tasks, to evaluate changes in brain oscillatory patterns such as mu and beta rhythms. Moreover, we measured motor-evoked potentials before and after cTBS to assess its impact on brain's excitability. On the hemisphere contralateral to the protocol, we did observe a significant increase in mu (p = 0.027) and beta (p = 0.006) rhythms from pre- to post-cTBS, at the beginning of arm elevation. The topology of action planning and motor execution suggests that cTBS produced an inhibitory effect that propagated to the contralateral hemisphere, thereby precluding the expected/desired excitation for therapy purposes. This novel approach provides support for the notion that this protocol induces inhibitory changes in contralateral motor rhythms, by decreasing desynchronization, contradicting the ipsilateral inhibition vs. contralateral disinhibition hypothesis. Our results have implications for personalized cTBS usage as a rehabilitation intervention, suggesting that an unexpected propagation of inhibition can occur.
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Affiliation(s)
- Ana Dionísio
- Coimbra Institute for Biomedical Imaging and Translational Research (CIBIT), Institute of Nuclear Sciences Applied to Health (ICNAS), University of Coimbra, Azinhaga de Santa Comba, 3000-548, Coimbra, Portugal.,Department of Physics, Faculty of Sciences and Technology, University of Coimbra, Coimbra, Portugal.,Institute for Biomedical Imaging and Life Sciences (CNC.IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Rita Gouveia
- Coimbra Institute for Biomedical Imaging and Translational Research (CIBIT), Institute of Nuclear Sciences Applied to Health (ICNAS), University of Coimbra, Azinhaga de Santa Comba, 3000-548, Coimbra, Portugal
| | - Isabel Catarina Duarte
- Coimbra Institute for Biomedical Imaging and Translational Research (CIBIT), Institute of Nuclear Sciences Applied to Health (ICNAS), University of Coimbra, Azinhaga de Santa Comba, 3000-548, Coimbra, Portugal.,Institute for Biomedical Imaging and Life Sciences (CNC.IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - João Castelhano
- Coimbra Institute for Biomedical Imaging and Translational Research (CIBIT), Institute of Nuclear Sciences Applied to Health (ICNAS), University of Coimbra, Azinhaga de Santa Comba, 3000-548, Coimbra, Portugal.,Institute for Biomedical Imaging and Life Sciences (CNC.IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Felix Duecker
- Coimbra Institute for Biomedical Imaging and Translational Research (CIBIT), Institute of Nuclear Sciences Applied to Health (ICNAS), University of Coimbra, Azinhaga de Santa Comba, 3000-548, Coimbra, Portugal.,Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands.,Maastricht Brain Imaging Center, Maastricht University, Maastricht, The Netherlands
| | - Miguel Castelo-Branco
- Coimbra Institute for Biomedical Imaging and Translational Research (CIBIT), Institute of Nuclear Sciences Applied to Health (ICNAS), University of Coimbra, Azinhaga de Santa Comba, 3000-548, Coimbra, Portugal. .,Institute for Biomedical Imaging and Life Sciences (CNC.IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal. .,Brain Imaging Network, University of Coimbra, Coimbra, Portugal.
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14
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Schuhmann T, Kemmerer SK, Duecker F, de Graaf TA, ten Oever S, De Weerd P, Sack AT. Left parietal tACS at alpha frequency induces a shift of visuospatial attention. PLoS One 2019; 14:e0217729. [PMID: 31774818 PMCID: PMC6881009 DOI: 10.1371/journal.pone.0217729] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 11/12/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Voluntary shifts of visuospatial attention are associated with a lateralization of parieto-occipital alpha power (7-13Hz), i.e. higher power in the hemisphere ipsilateral and lower power contralateral to the locus of attention. Recent noninvasive neuromodulation studies demonstrated that alpha power can be experimentally increased using transcranial alternating current stimulation (tACS). OBJECTIVE/HYPOTHESIS We hypothesized that tACS at alpha frequency over the left parietal cortex induces shifts of attention to the left hemifield. However, spatial attention shifts not only occur voluntarily (endogenous/ top-down), but also stimulus-driven (exogenous/ bottom-up). To study the task-specificity of the potential effects of tACS on attentional processes, we administered three conceptually different spatial attention tasks. METHODS 36 healthy volunteers were recruited from an academic environment. In two separate sessions, we applied either high-density tACS at 10Hz, or sham tACS, for 35-40 minutes to their left parietal cortex. We systematically compared performance on endogenous attention, exogenous attention, and stimulus detection tasks. RESULTS In the endogenous attention task, a greater leftward bias in reaction times was induced during left parietal 10Hz tACS as compared to sham. There were no stimulation effects in either the exogenous attention or the stimulus detection task. CONCLUSION The study demonstrates that high-density tACS at 10Hz can be used to modulate visuospatial attention performance. The tACS effect is task-specific, indicating that not all forms of attention are equally susceptible to the stimulation.
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Affiliation(s)
- Teresa Schuhmann
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
- Brain Imaging Center, Maastricht, The Netherlands
| | - Selma K. Kemmerer
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
- Brain Imaging Center, Maastricht, The Netherlands
| | - Felix Duecker
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
- Brain Imaging Center, Maastricht, The Netherlands
| | - Tom A. de Graaf
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
- Brain Imaging Center, Maastricht, The Netherlands
| | - Sanne ten Oever
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
- Brain Imaging Center, Maastricht, The Netherlands
| | - Peter De Weerd
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
- Brain Imaging Center, Maastricht, The Netherlands
| | - Alexander T. Sack
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
- Brain Imaging Center, Maastricht, The Netherlands
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNs), Brain + Nerve Centre, Maastricht University Medical Centre+ (MUMC+), Maastricht, The Netherlands
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15
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Gurel SC, Castelo-Branco M, Sack AT, Duecker F. Assessing the Functional Role of Frontal Eye Fields in Voluntary and Reflexive Saccades Using Continuous Theta Burst Stimulation. Front Neurosci 2018; 12:944. [PMID: 30618573 PMCID: PMC6302006 DOI: 10.3389/fnins.2018.00944] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 11/29/2018] [Indexed: 11/15/2022] Open
Abstract
The frontal eye fields (FEFs) are core nodes of the oculomotor system contributing to saccade planning, control, and execution. Here, we aimed to reveal hemispheric asymmetries between left and right FEF in both voluntary and reflexive saccades toward horizontal and vertical targets. To this end, we applied fMRI-guided continuous theta burst stimulation (cTBS) over either left or right FEF and assessed the consequences of this disruption on saccade latencies. Using a fully counterbalanced within-subject design, we measured saccade latencies before and after the application of cTBS in eighteen healthy volunteers. In general, saccade latencies on both tasks were susceptible to our experimental manipulations, that is, voluntary saccades were slower than reflexive saccades, and downward saccades were slower than upward saccades. Contrary to our expectations, we failed to reveal any TMS-related effects on saccade latencies, and Bayesian analyses provided strong support in favor of a TMS null result for both tasks. Keeping in mind the interpretative challenges of null results, we discuss possible explanations for this absence of behavioral TMS effects, focusing on methodological differences compared to previous studies (task parameters and online vs. offline TMS interventions). We also speculate about what our results might reveal about the functional role of FEF.
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Affiliation(s)
- Seref Can Gurel
- Brain Stimulation and Cognition Group, Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands
- Maastricht Brain Imaging Center, Maastricht, Netherlands
- Department of Psychiatry, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Miguel Castelo-Branco
- Coimbra Institute for Biomedical Imaging and Translational Research, Coimbra, Portugal
| | - Alexander T. Sack
- Brain Stimulation and Cognition Group, Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands
- Maastricht Brain Imaging Center, Maastricht, Netherlands
| | - Felix Duecker
- Brain Stimulation and Cognition Group, Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands
- Maastricht Brain Imaging Center, Maastricht, Netherlands
- Coimbra Institute for Biomedical Imaging and Translational Research, Coimbra, Portugal
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16
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Abstract
Pulses of transcranial magnetic stimulation (TMS) over occipital cortex can induce transient visual percepts called phosphenes. Phosphenes are an interesting stimulus for the study of the human visual system, constituting conscious percepts without visual inputs, elicited by neural activation beyond retinal and subcortical processing stages in the visual hierarchy. The same TMS pulses, applied at threshold intensity phosphene threshold (PT), will prompt phosphene reports on half of all trials ("P-yes") but not on the other half ("P-no"). Contrasting brain activity (P-yes > P-no) can provide unique information on neural mechanisms underlying conscious percepts, as has been demonstrated by published EEG studies. Yet to our knowledge no articles reporting analogous contrasts with functional magnetic resonance imaging (fMRI) have been published. Since it seems unlikely that such studies have never been performed, this straightforward and technically feasible idea may have been explored in multiple failed, and unpublished, attempts. Here, we argue why such unsuccessful attempts, even small-scale, best be shared. We also report our own failed attempt to find phosphene-related activity in fMRI. Threshold phosphenes are weak percepts, and their detection subjective and difficult. If fMRI correlates of phosphenes are obtainable with this contrast, small-scale ('pilot') measurements may not be sufficiently powerful to detect them. At the same time, due to the challenges and costs involved in TMS-fMRI, attempts might not often get beyond the piloting stage. We propose that the only way out of this quandary is the communication and sharing of such unsuccessful attempts and associated data.
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Affiliation(s)
- Tom A. de Graaf
- Section Brain Stimulation and Cognition, Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands
- Maastricht Brain Imaging Centre, Maastricht, Netherlands
| | - Job van den Hurk
- Maastricht Brain Imaging Centre, Maastricht, Netherlands
- Scannexus, Maastricht, Netherlands
| | - Felix Duecker
- Section Brain Stimulation and Cognition, Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands
- Maastricht Brain Imaging Centre, Maastricht, Netherlands
| | - Alexander T. Sack
- Section Brain Stimulation and Cognition, Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands
- Maastricht Brain Imaging Centre, Maastricht, Netherlands
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17
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Mayrhofer HC, Duecker F, van de Ven V, Jacobs HIL, Sack AT. Hemifield-specific Correlations between Cue-related Blood Oxygen Level Dependent Activity in Bilateral Nodes of the Dorsal Attention Network and Attentional Benefits in a Spatial Orienting Paradigm. J Cogn Neurosci 2018; 31:625-638. [PMID: 30240311 DOI: 10.1162/jocn_a_01338] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
The dorsal attention network (DAN) is known to be involved in shifts of spatial attention or in orienting. However, the involvement of each hemisphere in shifts to either hemifield is still a matter of debate. In this study, interindividual hemifield-specific attentional benefits in RTs were correlated with cue-related BOLD responses specific to directive cues in the left and right frontal and posterior nodes of the DAN, measured in a Spatial Orienting Paradigm. The pattern of correlations was analyzed with respect to its fit with three existing hypotheses of spatial attention control: the contralateral, right dominance, and hybrid hypotheses. Results showed that activation in frontal and parietal nodes of the DAN could explain a significant proportion of the interindividual variance in attentional benefits. Although we found that benefits in the right hemifield correlated with cue-related activity in the left, as well as the right, DAN and that the pattern of correlations fit best with the right dominance hypothesis, there were no significant correlations between left benefits and activation in the right (as well as left) DAN, which precludes the conclusion that our data support the right dominance hypothesis and might instead point toward a potential qualitative difference between leftward and rightward shifts of attention. In conclusion, this study demonstrates that behavioral effects of orienting can be linked to activation changes in the DAN, and it raises new questions with respect to the involvement of the frontal and parietal nodes in each hemisphere in hemifield-specific orienting.
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Affiliation(s)
| | | | | | - Heidi I L Jacobs
- Maastricht University.,Massachusetts General Hospital/Harvard Medical School
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18
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de Graaf T, Duecker F, Stankevich Y, ten Oever S, Sack A. Seeing in the dark: Phosphene thresholds with eyes open versus closed in the absence of visual inputs. Brain Stimul 2017; 10:828-835. [DOI: 10.1016/j.brs.2017.04.127] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 02/24/2017] [Accepted: 04/23/2017] [Indexed: 01/13/2023] Open
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Duecker F, Schuhmann T, Bien N, Jacobs C, Sack AT. Moving Beyond Attentional Biases: Shifting the Interhemispheric Balance between Left and Right Posterior Parietal Cortex Modulates Attentional Control Processes. J Cogn Neurosci 2017; 29:1267-1278. [DOI: 10.1162/jocn_a_01119] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Abstract
The concept of interhemispheric competition has been very influential in attention research, and the occurrence of biased attention due to an imbalance in posterior parietal cortex (PPC) is well documented. In this context, the vast majority of studies have assessed attentional performance with tasks that did not include an explicit experimental manipulation of attention, and, as a consequence, it remains largely unknown how these findings relate to core attentional constructs such as endogenous and exogenous control and spatial orienting and reorienting. We here addressed this open question by creating an imbalance between left and right PPC with transcranial direct current stimulation, resulting in right-hemispheric dominance, and assessed performance on three experimental paradigms that isolate distinct attentional processes. The comparison between active and sham transcranial direct current stimulations revealed a highly informative pattern of results with differential effects across tasks. Our results demonstrate the functional necessity of PPC for endogenous and exogenous attentional control and, importantly, link the concept of interhemispheric competition to core attentional processes, thus moving beyond the notion of biased attention after noninvasive brain stimulation over PPC.
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Emmerling F, Duecker F, de Graaf TA, Schuhmann T, Adam JJ, Sack AT. Foresight beats hindsight: The neural correlates underlying motor preparation in the pro-/anti-cue paradigm. Brain Behav 2017; 7:e00663. [PMID: 28523216 PMCID: PMC5434179 DOI: 10.1002/brb3.663] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 01/16/2017] [Accepted: 01/17/2017] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Human motor behaviors are characterized by both, reactive and proactive mechanisms. Yet, studies investigating the neural correlates of motor behavior almost exclusively focused on reactive motor processes. Here, we employed the pro-/anti-cue motor preparation paradigm to systematically study proactive motor control in an imaging environment. In this paradigm, either pro- or anti-cues are presented in a blocked design. Four fingers (two from each hand) are mapped onto four visual target locations. Visual targets require a speeded response by one corresponding finger, but, most importantly, they are preceded by visual cues that are congruent ("pro-cue"), incongruent ("anti-cue"), or neutral with respect to the responding hand. With short cue-target intervals, congruence effects are based on automatic motor priming of the correct hand (in case of pro-cues) or incorrect hand (in case of anti-cues), generating, respectively, reaction time benefits or reaction time costs relative to the neutral-cue. With longer cue-target intervals, slower top-down processes become effective, transforming early anti-cue interference into late anti-cue facilitation. METHODS We adapted this paradigm to be compatible with neuroimaging, tested and validated it behaviorally-both inside and outside the imaging environment-and implemented it in a whole-brain functional magnetic resonance imaging study. RESULTS AND CONCLUSION Our imaging results indicate that pro-cues elicited much less neural activation than did anti-cues, the latter recruiting well-known cognitive top-down networks related to attention, response inhibition, and error monitoring/signaling, thereby revealing high-level influences on proactive motor processes.
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Affiliation(s)
- Franziska Emmerling
- Department of Cognitive Neuroscience Faculty of Psychology and Neuroscience Maastricht University Maastricht The Netherlands.,Maastricht Brain Imaging Center Maastricht The Netherlands
| | - Felix Duecker
- Department of Cognitive Neuroscience Faculty of Psychology and Neuroscience Maastricht University Maastricht The Netherlands.,Maastricht Brain Imaging Center Maastricht The Netherlands
| | - Tom A de Graaf
- Department of Cognitive Neuroscience Faculty of Psychology and Neuroscience Maastricht University Maastricht The Netherlands.,Maastricht Brain Imaging Center Maastricht The Netherlands
| | - Teresa Schuhmann
- Department of Cognitive Neuroscience Faculty of Psychology and Neuroscience Maastricht University Maastricht The Netherlands.,Maastricht Brain Imaging Center Maastricht The Netherlands
| | - Jos J Adam
- Department of Human Biology and Movement Sciences Faculty of Health, Medicine, and Life Sciences Maastricht University Maastricht The Netherlands
| | - Alexander T Sack
- Department of Cognitive Neuroscience Faculty of Psychology and Neuroscience Maastricht University Maastricht The Netherlands.,Maastricht Brain Imaging Center Maastricht The Netherlands
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Duecker F, Schilberg L, Sack A. P222 Manipulation of connectivity in the dorsal attention network and its effects on attentional control. Clin Neurophysiol 2017. [DOI: 10.1016/j.clinph.2016.10.339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Veniero D, Morand S, Duecker F, Sack A, Gross J, Thut G. P213 Frontal eye fields control visual cortex excitability by phase aligning beta oscillations: A bifocal transcranial magnetic stimulation (TMS) study. Clin Neurophysiol 2017. [DOI: 10.1016/j.clinph.2016.10.330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Goffaux V, Duecker F, Hausfeld L, Schiltz C, Goebel R. Horizontal tuning for faces originates in high-level Fusiform Face Area. Neuropsychologia 2016; 81:1-11. [DOI: 10.1016/j.neuropsychologia.2015.12.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 11/23/2015] [Accepted: 12/06/2015] [Indexed: 10/22/2022]
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Abstract
Sham transcranial magnetic stimulation (TMS) approaches are widely used in basic and clinical research to ensure that observed effects are due to the intended neural manipulation instead of being caused by various possible side effects. We here critically discuss several methodological aspects of sham TMS. Importantly, we propose to carefully distinguish between the placebo versus sensory side effects of TMS. In line with this conceptual distinction, we describe current limitations of sham TMS approaches in the context of placebo effects and blinding success, followed by a short review of our own work demonstrating that the sensory side effects of sham TMS are not unspecific as often falsely assumed. Lastly, we argue that sham TMS approaches are inherently insufficient as full-fledged control conditions as they fail to demonstrate the specificity of TMS effects to a particular brain area or time point of stimulation. Sham TMS should therefore only complement alternative control strategies in TMS research.
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Affiliation(s)
- Felix Duecker
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University , Maastricht, Netherlands ; Maastricht Brain Imaging Center, Maastricht University , Maastricht, Netherlands
| | - Alexander T Sack
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University , Maastricht, Netherlands ; Maastricht Brain Imaging Center, Maastricht University , Maastricht, Netherlands
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de Graaf TA, Duecker F, Fernholz MHP, Sack AT. Spatially specific vs. unspecific disruption of visual orientation perception using chronometric pre-stimulus TMS. Front Behav Neurosci 2015; 9:5. [PMID: 25688194 PMCID: PMC4311643 DOI: 10.3389/fnbeh.2015.00005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 01/08/2015] [Indexed: 11/13/2022] Open
Abstract
Transcranial magnetic stimulation (TMS) over occipital cortex can impair visual processing. Such "TMS masking" has repeatedly been shown at several stimulus onset asynchronies (SOAs), with TMS pulses generally applied after the onset of a visual stimulus. Following increased interest in the neuronal state-dependency of visual processing, we recently explored the efficacy of TMS at "negative SOAs", when no visual processing can yet occur. We could reveal pre-stimulus TMS disruption, with results moreover hinting at two separate mechanisms in occipital cortex biasing subsequent orientation perception. Here we extended this work, including a chronometric design to map the temporal dynamics of spatially specific and unspecific mechanisms of state-dependent visual processing, while moreover controlling for TMS-induced pupil covering. TMS pulses applied 60-40 ms prior to a visual stimulus decreased orientation processing independent of stimulus location, while a local suppressive effect was found for TMS applied 30-10 ms pre-stimulus. These results contribute to our understanding of spatiotemporal mechanisms in occipital cortex underlying the state-dependency of visual processing, providing a basis for future work to link pre-stimulus TMS suppression effects to other known visual biasing mechanisms.
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Affiliation(s)
- Tom A de Graaf
- Faculty of Psychology and Neuroscience, Department of Cognitive Neuroscience, Maastricht University Maastricht, Netherlands ; Maastricht Brain Imaging Centre Maastricht, Netherlands
| | - Felix Duecker
- Faculty of Psychology and Neuroscience, Department of Cognitive Neuroscience, Maastricht University Maastricht, Netherlands ; Maastricht Brain Imaging Centre Maastricht, Netherlands
| | - Martin H P Fernholz
- Faculty of Psychology and Neuroscience, Department of Cognitive Neuroscience, Maastricht University Maastricht, Netherlands ; Maastricht Brain Imaging Centre Maastricht, Netherlands
| | - Alexander T Sack
- Faculty of Psychology and Neuroscience, Department of Cognitive Neuroscience, Maastricht University Maastricht, Netherlands ; Maastricht Brain Imaging Centre Maastricht, Netherlands
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Duecker F, Sack AT. The hybrid model of attentional control: New insights into hemispheric asymmetries inferred from TMS research. Neuropsychologia 2014; 74:21-9. [PMID: 25451041 DOI: 10.1016/j.neuropsychologia.2014.11.023] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 11/17/2014] [Accepted: 11/19/2014] [Indexed: 11/19/2022]
Abstract
Several competing theories on the mechanisms underlying attentional control have emerged over the years that, despite their substantial differences, all emphasize the importance of hemispheric asymmetries. Transcranial magnetic stimulation (TMS) has proven particularly successful in teasing them apart by selective perturbation of the dorsal and ventral fronto-parietal network. We here critically review the TMS literature and show that hemispheric asymmetries within the dorsal attention network differ between parietal and frontal cortex. Specifically, posterior parietal cortex seems to be characterized by a contralateral bias of each hemisphere and competition between them. In contrast, the right frontal eye field seems to be involved in shifting attention toward both hemifields, whereas left frontal eye field is only involved on shifting attention toward the contralateral hemifield. In the light of presented evidence, we propose to revise the functional-anatomical model originally proposed by Corbetta and Shulman (2011, 2002) and introduce a hybrid model of hemispheric asymmetries in attentional control.
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Affiliation(s)
- Felix Duecker
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands; Maastricht Brain Imaging Center, Maastricht University, Maastricht, The Netherlands.
| | - Alexander T Sack
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands; Maastricht Brain Imaging Center, Maastricht University, Maastricht, The Netherlands
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Duecker F, de Graaf TA, Sack AT. Thinking caps for everyone? The role of neuro-enhancement by non-invasive brain stimulation in neuroscience and beyond. Front Syst Neurosci 2014; 8:71. [PMID: 24808835 PMCID: PMC4010788 DOI: 10.3389/fnsys.2014.00071] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 04/10/2014] [Indexed: 11/13/2022] Open
Abstract
Neuro-enhancement by non-invasive brain stimulation (NIBS) has recently made considerable progress, triggering discussions regarding future applications to enhance human performance. We show that neuroscientific research does not aim at improving brain functions per se. Instead, neuro-enhancement is a research tool that has great potential to reveal the neural mechanisms underlying perception, cognition, and behavior. We provide instructive examples that showcase the relevance of neuro-enhancement by NIBS in neuroscience. Importantly, we argue that the scientific value of neuro-enhancement critically depends on our understanding of why enhancing effects occur. This is in contrast to applications of neuro-enhancement in other domains, where such knowledge may not be required. We conclude that neuro-enhancement as a therapeutic tool or in healthy people outside of neuroscience should be kept conceptually distinct, as these are separate domains with entirely different motives for enhancing human performance. Consequently, the underlying principles that justify the application of NIBS will be different in each domain and arguments for or against neuro-enhancement in one domain do not necessarily generalize to other domains.
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Affiliation(s)
- Felix Duecker
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University Maastricht, Netherlands ; Maastricht Brain Imaging Center, Maastricht University Maastricht, Netherlands
| | - Tom A de Graaf
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University Maastricht, Netherlands ; Maastricht Brain Imaging Center, Maastricht University Maastricht, Netherlands
| | - Alexander T Sack
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University Maastricht, Netherlands ; Maastricht Brain Imaging Center, Maastricht University Maastricht, Netherlands
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Duecker F, Frost MA, de Graaf TA, Graewe B, Jacobs C, Goebel R, Sack AT. The cortex-based alignment approach to TMS coil positioning. J Cogn Neurosci 2014; 26:2321-9. [PMID: 24702449 DOI: 10.1162/jocn_a_00635] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
TMS allows noninvasive manipulation of brain activity in healthy participants and patients. The effectiveness of TMS experiments critically depends on precise TMS coil positioning, which is best for most brain areas when a frameless stereotactic system is used to target activation foci based on individual fMRI data. From a purely scientific perspective, individual fMRI-guided TMS is thus the method of choice to ensure optimal TMS efficiency. Yet, from a more practical perspective, such individual functional data are not always available, and therefore alternative TMS coil positioning approaches are often applied, for example, based on functional group data reported in Talairach coordinates. We here propose a novel method for TMS coil positioning that is based on functional group data, yet only requires individual anatomical data. We used cortex-based alignment (CBA) to transform individual anatomical data to an atlas brain that includes probabilistic group maps of two functional regions (FEF and hMT+/V5). Then, these functional group maps were back-transformed to the individual brain anatomy, preserving functional-anatomical correspondence. As a proof of principle, the resulting CBA-based functional targets in individual brain space were compared with individual FEF and hMT+/V5 hotspots as conventionally localized with individual fMRI data and with targets based on Talairach coordinates as commonly done in TMS research in case only individual anatomical data are available. The CBA-based approach significantly improved localization of functional brain areas compared with traditional Talairach-based targeting. Given the widespread availability of CBA schemes and preexisting functional group data, the proposed procedure is easy to implement and at no additional measurement costs. However, the accuracy of individual fMRI-guided TMS remains unparalleled, and the CBA-based approach should only be the method of choice when individual functional data cannot be obtained or experimental factors argue against it.
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Abstract
Transcranial magnetic stimulation (TMS) is widely used in experimental brain research to manipulate brain activity in humans. Next to the intended neural effects, every TMS pulse produces a distinct clicking sound and sensation on the head which can also influence task performance. This necessitates careful consideration of control conditions in order to ensure that behavioral effects of interest can be attributed to the neural consequences of TMS and not to non-neural effects of a TMS pulse. Surprisingly, even though these non-neural effects of TMS are largely unknown, they are often assumed to be unspecific, i.e. not dependent on TMS parameters. This assumption is inherent to many control strategies in TMS research but has recently been challenged on empirical grounds. Here, we further develop the empirical basis of control strategies in TMS research. We investigated the time-dependence and task-dependence of the non-neural effects of TMS and compared real and sham TMS over vertex. Critically, we show that non-neural TMS effects depend on a complex interplay of these factors. Although TMS had no direct neural effects, both pre- and post-stimulus TMS time windows modulated task performance on both a sensory detection task and a cognitive angle judgment task. For the most part, these effects were quantitatively similar across tasks but effect sizes were clearly different. Moreover, the effects of real and sham TMS were almost identical with interesting exceptions that shed light on the relative contribution of auditory and somato-sensory aspects of a TMS pulse. Knowledge of such effects is of critical importance for the interpretation of TMS experiments and helps deciding what constitutes an appropriate control condition. Our results broaden the empirical basis of control strategies in TMS research and point at potential pitfalls that should be avoided.
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Affiliation(s)
- Felix Duecker
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
- Maastricht Brain Imaging Center, Maastricht University, Maastricht, The Netherlands
| | - Tom A. de Graaf
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
- Maastricht Brain Imaging Center, Maastricht University, Maastricht, The Netherlands
| | - Christianne Jacobs
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
- Maastricht Brain Imaging Center, Maastricht University, Maastricht, The Netherlands
| | - Alexander T. Sack
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
- Maastricht Brain Imaging Center, Maastricht University, Maastricht, The Netherlands
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Duecker F, Formisano E, Sack AT. Hemispheric differences in the voluntary control of spatial attention: direct evidence for a right-hemispheric dominance within frontal cortex. J Cogn Neurosci 2013; 25:1332-42. [PMID: 23574586 DOI: 10.1162/jocn_a_00402] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Lesion studies in neglect patients have inspired two competing models of spatial attention control, namely, Heilman's "hemispatial" theory and Kinsbourne's "opponent processor" model. Both assume a functional asymmetry between the two hemispheres but propose very different mechanisms. Neuroimaging studies have identified a bilateral dorsal frontoparietal network underlying voluntary shifts of spatial attention. However, lateralization of attentional processes within this network has not been consistently reported. In the current study, we aimed to provide direct evidence concerning the functional asymmetry of the right and left FEF during voluntary shifts of spatial attention. To this end, we applied fMRI-guided neuronavigation to disrupt individual FEF activation foci with a longer-lasting inhibitory patterned TMS protocol followed by a spatial cueing task. Our results indicate that right FEF stimulation impaired the ability of shifting spatial attention toward both hemifields, whereas the effects of left FEF stimulation were limited to the contralateral hemifield. These results provide strong direct evidence for right-hemispheric dominance in spatial attention within frontal cortex supporting Heilman's "hemispatial" theory. This complements previous TMS studies that generally conform to Kinsbourne's "opponent processor" model after disruption of parietal cortex, and we therefore propose that both theories are not mutually exclusive.
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Affiliation(s)
- Felix Duecker
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands.
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Platz T, Roschka S, Christel MI, Duecker F, Rothwell JC, Sack AT, Sack A. Early stages of motor skill learning and the specific relevance of the cortical motor system--a combined behavioural training and θ burst TMS study. Restor Neurol Neurosci 2013; 30:199-211. [PMID: 22398421 DOI: 10.3233/rnn-2012-110204] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
PURPOSE To examine whether motor performance and motor learning in healthy subjects can be segregated into a number of distinct motor abilities which are linked to intact processing in different motor-related brain regions (M1, S1, SMA, PMC) early during learning. METHODS Seven young healthy subjects trained in eight motor arm tasks (Arm Ability Training, AAT) once a day for 5 days using their left non-dominant arm. Except for day 1 (baseline), training was performed before and after applying an inhibitory form of repetitive transcranial magnetic stimulation (cTBS, continuous theta burst) to either M1, S1, SMA, or PMC. RESULTS A principal component analysis of the motor behaviour data suggested four independent motor abilities: aiming, speed, steadiness, and visuomotor tracking. AAT induced substantial motor learning across abilities. Within session effects of cTBS revealed that activity in primary somatosensory cortex (S1) was relevant for motor performance and learning across all tasks whereas M1 was specifically involved in rapid tapping movements, PMC in ballistic arm navigation in extra-personal space; performance on a non-trained motor tasks was not affected by cTBS. CONCLUSIONS Cortical sensory and motor areas including S1, M1, and PMC functionally contribute to early motor learning in a differential manner across motor abilities.
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Affiliation(s)
- Thomas Platz
- BDH-Klinik Greifswald, Neurorehabilitation Centre and Spinal Cord Injury Unit, Neuroscience Department, Ernst-Moritz-Arndt-Universität, Greifswald, Germany.
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Abstract
Transcranial magnetic stimulation (TMS) allows non-invasive manipulation of brain activity during active task performance. Because every TMS pulse is accompanied by non-neural effects such as a clicking sound and somato-sensation on the head, control conditions are required to ensure that changes in task behavior are indeed due to the induced neural effects. However, the non-neural effects of TMS in the context of a given task performance are largely unknown and, consequently, it is unclear what constitutes a valid control condition. We explored the non-neural effects of TMS on visual target detection. Participants received single pulse sham TMS to each hemisphere at different time points prior to target appearance during a visual target detection task. It was hypothesized that the clicking sound of a sham TMS pulse differentially affects performance depending on the location of the coil and the timing of the pulse.Our results show that, first, sham TMS caused a facilitation of reaction times when preceding the target stimulus by 150, 200, and 250 ms, whereas earlier and later time windows were not effective. Second, positioning the TMS coil ipsilateral instead of contralateral relative to the target stimulus improved reaction times. Third, infrequent noTMS trials that were interleaved with sham TMS trials had oddball-like properties resulting in increased reaction times during noTMS. The clicking sound produced by sham TMS influences task performance in multiple ways. These non-neural effects of TMS need to be controlled for in TMS research and the present findings provide an empirical basis for deciding what constitutes a valid control condition.
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Affiliation(s)
- Felix Duecker
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands.
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Goffaux V, Duecker F, Schiltz C, Goebel R. Orientation tuning for faces in the Fusiform Face Area and Primary Visual Cortex. J Vis 2012. [DOI: 10.1167/12.9.27] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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