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Oda H, Tsujinaka R, Fukuda S, Hamada N, Matsuoka M, Hiraoka K. Descending motor command to prime mover of dependent finger induces tactile gating in target and distant non-target finger. Somatosens Mot Res 2024:1-8. [PMID: 38785341 DOI: 10.1080/08990220.2024.2358298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 05/16/2024] [Indexed: 05/25/2024]
Abstract
This study examined whether tactile gating induced by the descending motor command to one finger spreads out to the other fingers to which the command is not delivered and whether this gating is dependent on the target finger to which the command is delivered. The change in perceptual threshold to the digital nerve stimulation of one finger induced by tonic contraction of the first dorsal interosseous or abductor digiti minimi muscle was examined. The perceptual threshold to the digital nerve stimulation of the thumb or little finger was increased by tonic contraction of the abductor digiti minimi muscle. This finding indicates that the descending motor command to the prime mover of the little finger abduction induces tactile gating not only in the finger to which the command is delivered but also in the other finger to which the command is not delivered. Tonic contraction of the first dorsal interosseous muscle did not change the perceptual threshold to the digital nerve stimulation in any finger. This finding means that tactile gating occurs particularly when the descending motor command is delivered to the dependent finger. Spreading out of tactile gating of one finger, to which the descending motor command is not delivered, is likely mediated by surround inhibition.
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Affiliation(s)
- Hitoshi Oda
- Graduate School of Rehabilitation Science, Osaka Metropolitan University, Habikino City, Japan
| | - Ryo Tsujinaka
- Graduate School of Comprehensive Rehabilitation, Osaka Prefecture University, Sakai, Japan
| | - Shiho Fukuda
- Graduate School of Rehabilitation Science, Osaka Metropolitan University, Habikino City, Japan
| | - Naoki Hamada
- Graduate School of Rehabilitation Science, Osaka Metropolitan University, Habikino City, Japan
| | - Masakazu Matsuoka
- Graduate School of Rehabilitation Science, Osaka Metropolitan University, Habikino City, Japan
| | - Koichi Hiraoka
- School of Medicine, Osaka Metropolitan University, Habikino City, Japan
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2
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Tsujinaka R, Oda H, Fukuda S, Hamada N, Matsuoka M, Hiraoka K. Afferent volley from the digital nerve induces short-latency facilitation of perceptual sensitivity and primary sensory cortex excitability. Exp Brain Res 2023; 241:1339-1351. [PMID: 37012374 DOI: 10.1007/s00221-023-06611-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 03/27/2023] [Indexed: 04/05/2023]
Abstract
The present study examined whether the perceptual sensitivity and excitability of the primary sensory cortex are modulated by the afferent volley from the digital nerve of a conditioned finger within a short period of time. The perceptual threshold of an electrical stimulus to the index finger (test stimulus) was decreased by a conditioning stimulus to the index finger 4 or 6 ms before the test stimulus, or by a stimulus to the middle or ring finger 2 ms before that. This is explained by the view that the afferent volleys from the digital nerves of the fingers converge in the somatosensory areas, causing spatial summation of the afferent inputs through a small number of synaptic relays, leading to the facilitation of perceptual sensitivity. The N20 component of the somatosensory-evoked potential was facilitated by a conditioning stimulus to the middle finger 4 ms before a test stimulus or to the thumb 2 ms before the test stimulus. This is explained by the view that the afferent volley from the digital nerve of the finger adjacent to the tested finger induces lateral facilitation of the representation of the tested finger in the primary sensory cortex through a small number of synaptic relays.
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Affiliation(s)
- Ryo Tsujinaka
- Graduate School of Comprehensive Rehabilitation, Osaka Prefecture University, Habikino City, Japan
| | - Hitoshi Oda
- Graduate School of Comprehensive Rehabilitation, Osaka Prefecture University, Habikino City, Japan
| | - Shiho Fukuda
- Department of Rehabilitation Science, School of Medicine, Osaka Metropolitan University, Habikino City, Japan
| | - Naoki Hamada
- Department of Rehabilitation Science, School of Medicine, Osaka Metropolitan University, Habikino City, Japan
| | - Masakazu Matsuoka
- Department of Rehabilitation Science, School of Medicine, Osaka Metropolitan University, Habikino City, Japan
| | - Koichi Hiraoka
- Department of Rehabilitation Science, School of Medicine, Osaka Metropolitan University, Habikino City, Japan.
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3
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Nordmark PF, Johansson RS. Disinhibition of Human Primary Somatosensory Cortex After Median Nerve Transection and Reinnervation. Front Hum Neurosci 2020; 14:166. [PMID: 32499687 PMCID: PMC7242759 DOI: 10.3389/fnhum.2020.00166] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 04/17/2020] [Indexed: 01/09/2023] Open
Abstract
Despite state-of-the-art surgical and postoperative treatment, median nerve transection causes lasting impaired hand function due to limitations in the nerve’s reinnervation ability. The defective innervation and thus controllability of the affected hand can shape the brain’s control of manual behaviors. Earlier studies of changes in the processing of tactile stimuli have focused mainly on stimulation of the reinnervated hand and lack sufficient control over the brain’s use of the tactile input in perceptual terms. Here we used fMRI to measure brain activity (BOLD-signal) in 11 people with median nerve injury and healthy controls (N = 11) when performing demanding tactile tasks using the tip of either the index or little finger of either hand. For the nerve-injured group, the left median nerve had been traumatically transected in the distal forearm and surgically repaired on average 8 years before the study. The hand representation of their contralesional (right) primary somatosensory cortex (S1) showed greater activity compared to controls when the left reinnervated index finger was used, but also when the left-hand little finger and the fingers of the right hand innervated by uninjured nerves were used. We argue that the overall increase in activity reflects a general disinhibition of contralesional S1 consistent with an augmented functional reorganizational plasticity being an ongoing feature of chronic recovery from nerve injury. Also, the nerve-injured showed increased activity within three prefrontal cortical areas implicated in higher-level behavioral processing (dorsal anterior cingulate cortex, left ventrolateral prefrontal and right dorsolateral prefrontal cortex), suggesting that processes supporting decision-making and response-selection were computationally more demanding due to the compromised tactile sensibility.
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Affiliation(s)
- Per F Nordmark
- Department of Integrative Medical Biology, Physiology Section, Umeå University, Umeå, Sweden.,Umeå Center for Functional Brain Imaging, Umeå University, Umeå, Sweden.,Department of Surgical and Perioperative Sciences, Section for Hand and Plastic Surgery, Umeå University, Umeå, Sweden
| | - Roland S Johansson
- Department of Integrative Medical Biology, Physiology Section, Umeå University, Umeå, Sweden.,Umeå Center for Functional Brain Imaging, Umeå University, Umeå, Sweden
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4
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Surface-based analysis increases the specificity of cortical activation patterns and connectivity results. Sci Rep 2020; 10:5737. [PMID: 32235885 PMCID: PMC7109138 DOI: 10.1038/s41598-020-62832-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 03/11/2020] [Indexed: 12/13/2022] Open
Abstract
Spatial smoothing of functional magnetic resonance imaging (fMRI) data can be performed on volumetric images and on the extracted surface of the brain. Smoothing on the unfolded cortex should theoretically improve the ability to separate signals between brain areas that are near together in the folded cortex but are more distant in the unfolded cortex. However, surface-based method approaches (SBA) are currently not utilized as standard procedure in the preprocessing of neuroimaging data. Recent improvements in the quality of cortical surface modeling and improvements in its usability nevertheless advocate this method. In the current study, we evaluated the benefits of an up-to-date surface-based smoothing in comparison to volume-based smoothing. We focused on the effect of signal contamination between different functional systems using the primary motor and primary somatosensory cortex as an example. We were particularly interested in how this signal contamination influences the results of activity and connectivity analyses for these brain regions. We addressed this question by performing fMRI on 19 subjects during a tactile stimulation paradigm and by using simulated BOLD responses. We demonstrated that volume-based smoothing causes contamination of the primary motor cortex by somatosensory cortical responses, leading to false positive motor activation. These false positive motor activations were not found by using surface-based smoothing for reasonable kernel sizes. Accordingly, volume-based smoothing caused an exaggeration of connectivity estimates between these regions. In conclusion, this study showed that surface-based smoothing decreases signal contamination considerably between neighboring functional brain regions and improves the validity of activity and connectivity results.
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5
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Cataldo A, Ferrè ER, di Pellegrino G, Haggard P. Why the whole is more than the sum of its parts: Salience-driven overestimation in aggregated tactile sensations. Q J Exp Psychol (Hove) 2019; 72:2509-2526. [PMID: 30971159 DOI: 10.1177/1747021819847131] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Experimental psychology often studies perception analytically, reducing its focus to minimal sensory units, such as thresholds or just noticeable differences in a single stimulus. Here, in contrast, we examine a synthetic aspect: how multiple inputs to a sensory system are aggregated into an overall percept. Participants in three experiments judged the total stimulus intensity for simultaneous electrical shocks to two digits. We tested whether the integration of component somatosensory stimuli into a total percept occurs automatically, or rather depends on the ability to consciously perceive discrepancy among components (Experiment 1), whether the discrepancy among these components influences sensitivity or/and perceptual bias in judging totals (Experiment 2), and whether the salience of each individual component stimulus affects perception of total intensity (Experiment 3). Perceptual aggregation of two simultaneous component events occurred both when participants could perceptually discriminate the two intensities, and also when they could not. Further, the actual discrepancy between the stimuli modulated both participants' sensitivity and perceptual bias: increasing discrepancies produced a systematic and progressive overestimation of total intensity. The degree of this bias depended primarily on the salience of the stronger stimulus in the pair. Overall, our results suggest that important nonlinear mechanisms contribute to sensory aggregation. The mind aggregates component inputs into a coherent and synthetic perceptual experience in a salience-weighted fashion that is not based on simple summation of inputs.
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Affiliation(s)
- Antonio Cataldo
- 1 Institute of Cognitive Neuroscience, University College London, London, UK.,2 Centre for Studies and Research in Cognitive Neuroscience, Alma Mater Studiorum -University of Bologna, Cesena, Italy.,3 Institute of Philosophy, School of Advanced Study, University of London, London, UK
| | | | - Giuseppe di Pellegrino
- 2 Centre for Studies and Research in Cognitive Neuroscience, Alma Mater Studiorum -University of Bologna, Cesena, Italy
| | - Patrick Haggard
- 1 Institute of Cognitive Neuroscience, University College London, London, UK.,3 Institute of Philosophy, School of Advanced Study, University of London, London, UK
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6
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How Visual Body Perception Influences Somatosensory Plasticity. Neural Plast 2018; 2018:7909684. [PMID: 29713338 PMCID: PMC5866863 DOI: 10.1155/2018/7909684] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 01/09/2018] [Accepted: 01/16/2018] [Indexed: 01/10/2023] Open
Abstract
The study of somatosensory plasticity offers unique insights into the neuronal mechanisms that underlie human adaptive and maladaptive plasticity. So far, little attention has been paid on the specific influence of visual body perception on somatosensory plasticity and learning in humans. Here, we review evidence on how visual body perception induces changes in the functional architecture of the somatosensory system and discuss the specific influence the social environment has on tactile plasticity and learning. We focus on studies that have been published in the areas of human cognitive and clinical neuroscience and refer to animal studies when appropriate. We discuss the therapeutic potential of socially mediated modulations of somatosensory plasticity and introduce specific paradigms to induce plastic changes under controlled conditions. This review offers a contribution to understanding the complex interactions between social perception and somatosensory learning by focusing on a novel research field: socially mediated sensory plasticity.
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7
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Qi HX, Wang F, Liao CC, Friedman RM, Tang C, Kaas JH, Avison MJ. Spatiotemporal trajectories of reactivation of somatosensory cortex by direct and secondary pathways after dorsal column lesions in squirrel monkeys. Neuroimage 2016; 142:431-453. [PMID: 27523450 DOI: 10.1016/j.neuroimage.2016.08.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 06/23/2016] [Accepted: 08/09/2016] [Indexed: 11/17/2022] Open
Abstract
After lesions of the somatosensory dorsal column (DC) pathway, the cortical hand representation can become unresponsive to tactile stimuli, but considerable responsiveness returns over weeks of post-lesion recovery. The reactivation suggests that preserved subthreshold sensory inputs become potentiated and axon sprouting occurs over time to mediate recovery. Here, we studied the recovery process in 3 squirrel monkeys, using high-resolution cerebral blood volume-based functional magnetic resonance imaging (CBV-fMRI) mapping of contralateral somatosensory cortex responsiveness to stimulation of distal finger pads with low and high level electrocutaneous stimulation (ES) before and 2, 4, and 6weeks after a mid-cervical level contralateral DC lesion. Both low and high intensity ES of digits revealed the expected somatotopy of the area 3b hand representation in pre-lesion monkeys, while in areas 1 and 3a, high intensity stimulation was more effective in activating somatotopic patterns. Six weeks post-lesion, and irrespective of the severity of loss of direct DC inputs (98%, 79%, 40%), somatosensory cortical area 3b of all three animals showed near complete recovery in terms of somatotopy and responsiveness to low and high intensity ES. However there was significant variability in the patterns and amplitudes of reactivation of individual digit territories within and between animals, reflecting differences in the degree of permanent and/or transient silencing of primary DC and secondary inputs 2weeks post-lesion, and their spatio-temporal trajectories of recovery between 2 and 6weeks. Similar variations in the silencing and recovery of somatotopy and responsiveness to high intensity ES in areas 3a and 1 are consistent with individual differences in damage to and recovery of DC and spinocuneate pathways, and possibly the potentiation of spinothalamic pathways. Thus, cortical deactivation and subsequent reactivation depends not only on the degree of DC lesion, but also on the severity and duration of loss of secondary as well as primary inputs revealed by low and high intensity ES.
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Affiliation(s)
- Hui-Xin Qi
- Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA.
| | - Feng Wang
- Institute of Imaging Science, Vanderbilt University, Nashville, TN 37240, USA; Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN 37240, USA
| | - Chia-Chi Liao
- Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA
| | - Robert M Friedman
- Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA
| | - Chaohui Tang
- Institute of Imaging Science, Vanderbilt University, Nashville, TN 37240, USA; Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN 37240, USA
| | - Jon H Kaas
- Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA; Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN 37240, USA
| | - Malcolm J Avison
- Institute of Imaging Science, Vanderbilt University, Nashville, TN 37240, USA; Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN 37240, USA; Pharmacology, Vanderbilt University, Nashville, TN 37240, USA
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8
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Brouwer GJ, Arnedo V, Offen S, Heeger DJ, Grant AC. Normalization in human somatosensory cortex. J Neurophysiol 2015; 114:2588-99. [PMID: 26311189 DOI: 10.1152/jn.00939.2014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 08/24/2015] [Indexed: 01/23/2023] Open
Abstract
Functional magnetic resonance imaging (fMRI) was used to measure activity in human somatosensory cortex and to test for cross-digit suppression. Subjects received stimulation (vibration of varying amplitudes) to the right thumb (target) with or without concurrent stimulation of the right middle finger (mask). Subjects were less sensitive to target stimulation (psychophysical detection thresholds were higher) when target and mask digits were stimulated concurrently compared with when the target was stimulated in isolation. fMRI voxels in a region of the left postcentral gyrus each responded when either digit was stimulated. A regression model (called a forward model) was used to separate the fMRI measurements from these voxels into two hypothetical channels, each of which responded selectively to only one of the two digits. For the channel tuned to the target digit, responses in the left postcentral gyrus increased with target stimulus amplitude but were suppressed by concurrent stimulation to the mask digit, evident as a shift in the gain of the response functions. For the channel tuned to the mask digit, a constant baseline response was evoked for all target amplitudes when the mask was absent and responses decreased with increasing target amplitude when the mask was concurrently presented. A computational model based on divisive normalization provided a good fit to the measurements for both mask-absent and target + mask stimulation. We conclude that the normalization model can explain cross-digit suppression in human somatosensory cortex, supporting the hypothesis that normalization is a canonical neural computation.
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Affiliation(s)
- Gijs Joost Brouwer
- Department of Psychology and Center for Neural Science, New York University, New York, New York; and
| | - Vanessa Arnedo
- Department of Neurology, State University of New York, Downstate Medical Center, Brooklyn, New York
| | - Shani Offen
- Department of Psychology and Center for Neural Science, New York University, New York, New York; and
| | - David J Heeger
- Department of Psychology and Center for Neural Science, New York University, New York, New York; and
| | - Arthur C Grant
- Department of Neurology, State University of New York, Downstate Medical Center, Brooklyn, New York
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9
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van der Zwaag W, Gruetter R, Martuzzi R. Stroking or Buzzing? A Comparison of Somatosensory Touch Stimuli Using 7 Tesla fMRI. PLoS One 2015; 10:e0134610. [PMID: 26285027 PMCID: PMC4540472 DOI: 10.1371/journal.pone.0134610] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 07/11/2015] [Indexed: 11/18/2022] Open
Abstract
Studying body representations in the brain helps us to understand how we humans relate to our own bodies. The in vivo mapping of the somatosensory cortex, where these representations are found, is greatly facilitated by the high spatial resolution and high sensitivity to brain activation available at ultra-high field. In this study, the use of different stimulus types for somatotopic mapping of the digits at ultra-high field, specifically manual stroking and mechanical stimulation, was compared in terms of sensitivity and specificity of the brain responses. Larger positive responses in digit regions of interest were found for manual stroking than for mechanical stimulation, both in terms of average and maximum t-value and in terms of number of voxels with significant responses to the tactile stimulation. Responses to manual stroking were higher throughout the entire post-central sulcus, but the difference was especially large on its posterior wall, i.e. in Brodmann area 2. During mechanical stimulation, cross-digit responses were more negative than during manual stroking, possibly caused by a faster habituation to the stimulus. These differences indicate that manual stroking is a highly suitable stimulus for fast somatotopic mapping procedures, especially if Brodmann area 2 is of interest.
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Affiliation(s)
- Wietske van der Zwaag
- Centre d’Imagerie Biomédicale (CIBM), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Spinoza Centre for Neuroimaging, Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, Netherlands
- * E-mail:
| | - Rolf Gruetter
- Centre d’Imagerie Biomédicale (CIBM), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Department of Radiology, University Hospital, Lausanne, Switzerland
- Department of Radiology, University Hospital, Geneva, Switzerland
| | - Roberto Martuzzi
- Center for Neuroprosthetics, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Laboratory of Cognitive Neuroscience, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Fondation Campus Biotech Geneva, Geneva, Switzerland
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10
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Hlushchuk Y, Simões-Franklin C, Nangini C, Hari R. Stimulus-rate sensitivity discerns area 3b of the human primary somatosensory cortex. PLoS One 2015; 10:e0128462. [PMID: 26020639 PMCID: PMC4447440 DOI: 10.1371/journal.pone.0128462] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Accepted: 04/27/2015] [Indexed: 11/30/2022] Open
Abstract
Previous studies have shown that the hemodynamic response of the primary somatosensory cortex (SI) to electrical median nerve stimulation doubles in strength when the stimulus rate (SR) increases from 1 to 5 Hz. Here we investigated whether such sensitivity to SR is homogenous within the functionally different subareas of the SI cortex, and whether SR sensitivity would help discern area 3b among the other SI subareas. We acquired 3-tesla functional magnetic resonance imaging (fMRI) data from nine healthy adults who received pneumotactile stimuli in 25-s blocks to three right-hand fingers, either at 1, 4, or 10 Hz. The main contrast (all stimulations pooled vs. baseline), applied to the whole brain, first limited the search to the whole SI cortex. The conjunction of SR-sensitive contrasts [4 Hz − 1 Hz] > 0 and [10 Hz − 1 Hz] > 0 ([4Hz − 1Hz] + [10Hz − 1Hz] > 0), applied to the SI cluster, then revealed an anterior-ventral subcluster that reacted more strongly to both 10-Hz and 4-Hz stimuli than to the 1-Hz stimuli. No other SR-sensitive clusters were found at the group-level in the whole-brain analysis. The site of the SR-sensitive SI subcluster corresponds to the canonical position of area 3b; such differentiation was also possible at the individual level in 5 out of 9 subjects. Thus the SR sensitivity of the BOLD response appears to discern area 3b among other subareas of the human SI cortex.
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Affiliation(s)
- Yevhen Hlushchuk
- Brain Research Unit, Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, 00076 AALTO, Espoo, Finland
- Advanced Magnetic Imaging Centre, Aalto NeuroImaging, Aalto University School of Science, 00076 AALTO, Espoo, Finland
- * E-mail:
| | - Cristina Simões-Franklin
- Brain Research Unit, Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, 00076 AALTO, Espoo, Finland
| | - Cathy Nangini
- Brain Research Unit, Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, 00076 AALTO, Espoo, Finland
- Advanced Magnetic Imaging Centre, Aalto NeuroImaging, Aalto University School of Science, 00076 AALTO, Espoo, Finland
| | - Riitta Hari
- Brain Research Unit, Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, 00076 AALTO, Espoo, Finland
- Advanced Magnetic Imaging Centre, Aalto NeuroImaging, Aalto University School of Science, 00076 AALTO, Espoo, Finland
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Besle J, Sánchez-Panchuelo RM, Bowtell R, Francis S, Schluppeck D. Event-related fMRI at 7T reveals overlapping cortical representations for adjacent fingertips in S1 of individual subjects. Hum Brain Mapp 2013; 35:2027-43. [PMID: 24014446 PMCID: PMC4216413 DOI: 10.1002/hbm.22310] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 03/25/2013] [Accepted: 04/02/2013] [Indexed: 11/21/2022] Open
Abstract
Recent fMRI studies of the human primary somatosensory cortex have been able to differentiate the cortical representations of different fingertips at a single‐subject level. These studies did not, however, investigate the expected overlap in cortical activation due to the stimulation of different fingers. Here, we used an event‐related design in six subjects at 7 Tesla to explore the overlap in cortical responses elicited in S1 by vibrotactile stimulation of the five fingertips. We found that all parts of S1 show some degree of spatial overlap between the cortical representations of adjacent or even nonadjacent fingertips. In S1, the posterior bank of the central sulcus showed less overlap than regions in the post‐central gyrus, which responded to up to five fingertips. The functional properties of these two areas are consistent with the known layout of cytoarchitectonically defined subareas, and we speculate that they correspond to subarea 3b (S1 proper) and subarea 1, respectively. In contrast with previous fMRI studies, however, we did not observe discrete activation clusters that could unequivocally be attributed to different subareas of S1. Venous maps based on T2*‐weighted structural images suggest that the observed overlap is not driven by extra‐vascular contributions from large veins. Hum Brain Mapp 35:2027–2043, 2014. © 2013 The Authors Human Brain Mapping published by Wiley Periodicals, Inc.
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Affiliation(s)
- Julien Besle
- Visual Neuroscience Group, School of Psychology, University of Nottingham, NG7 2RD, Nottingham, United Kingdom
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12
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Within-digit functional parcellation of Brodmann areas of the human primary somatosensory cortex using functional magnetic resonance imaging at 7 tesla. J Neurosci 2013; 32:15815-22. [PMID: 23136420 DOI: 10.1523/jneurosci.2501-12.2012] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The primary somatosensory cortex (S1) can be subdivided cytoarchitectonically into four distinct Brodmann areas (3a, 3b, 1, and 2), but these areas have never been successfully delineated in vivo in single human subjects. Here, we demonstrate the functional parcellation of four areas of S1 in individual human subjects based on high-resolution functional MRI measurements made at 7 T using vibrotactile stimulation. By stimulating four sites along the length of the index finger, we were able to identify and locate map reversals of the base to tip representation of the index finger in S1. We suggest that these reversals correspond to the areal borders between the mirrored representations in the four Brodmann areas, as predicted from electrophysiology measurements in nonhuman primates. In all subjects, maps were highly reproducible across scanning sessions and stable over weeks. In four of the six subjects scanned, four, mirrored, within-finger somatotopic maps defining the extent of the Brodmann areas could be directly observed on the cortical surface. In addition, by using multivariate classification analysis, the location of stimulation on the index finger (four distinct sites) could be decoded with a mean accuracy of 65% across subjects. Our measurements thus show that within-finger topography is present at the millimeter scale in the cortex and is highly reproducible. The ability to identify functional areas of S1 in vivo in individual subjects will provide a framework for investigating more complex aspects of tactile representation in S1.
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13
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Kuehn E, Mueller K, Turner R, Schütz-Bosbach S. The functional architecture of S1 during touch observation described with 7 T fMRI. Brain Struct Funct 2013; 219:119-40. [PMID: 23283478 PMCID: PMC3889700 DOI: 10.1007/s00429-012-0489-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 11/20/2012] [Indexed: 12/19/2022]
Abstract
Recent studies indicate that the primary somatosensory cortex (S1) is active not only when touch is physically perceived but also when it is merely observed to be experienced by another person. This social responsivity of S1 has important implications for our understanding of S1 functioning. However, S1 activity during touch observation has not been characterized in great detail to date. We focused on two features of the S1 functional architecture during touch observation, namely the topographical arrangement of index and middle finger receptive fields (RFs), and their dynamic shrinkage during concurrent activation. Both features have important implications for human behavior. We conducted two fMRI studies at 7 T, one where touch was physically perceived, and one where touch was observed. In the two experiments, participants either had their index finger and/or middle finger stimulated using paintbrushes, or just observed similar touch events on video. Our data show that observing and physically experiencing touch elicits overlapping activity changes in S1. In addition, observing touch to the index finger or the middle finger alone evoked topographically arranged activation foci in S1. Importantly, when co-activated, the index and middle finger RFs not only shrank during physical touch perception, but also during touch observation. Our data, therefore, indicate a similarity between the functional architecture of S1 during touch observation and physical touch perception with respect to single-digit topography and RF shrinkage. These results may allow the tentative conclusion that even primary somatosensory experiences, such as physical touch perception, can be shared amongst individuals.
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Affiliation(s)
- Esther Kuehn
- Max Planck Institute for Human Cognitive and Brain Sciences, Stephanstr. 1a, 04103, Leipzig, Germany,
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14
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Age-related changes in the somatosensory processing of tactile stimulation--an fMRI study. Behav Brain Res 2012; 238:259-64. [PMID: 23123141 DOI: 10.1016/j.bbr.2012.10.038] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Revised: 10/17/2012] [Accepted: 10/20/2012] [Indexed: 11/20/2022]
Abstract
Age-related changes in brain function are complex. Although ageing is associated with a reduction in cerebral blood flow and neuronal activity, task-related processing is often correlated with an enlargement of the corresponding and additionally recruited brain areas. This supplemental employment is considered an attempt to compensate for deficits in the ageing brain. Although there are contradictory reports regarding the role of the primary somatosensory cortex (SI), currently, there is little knowledge about age-related functional changes in other brain areas in the somatosensory network (secondary somatosensory cortex (SII), and insular, anterior (ACC) and posterior cingulate cortices (PCC)). We investigated 16 elderly (age range, 62-71 years) and 18 young subjects (age range, 21-28 years) by determining the current perception threshold (CPT) and applying functional magnetic resonance imaging (fMRI) using a 3.0 Tesla scanner under tactile stimulation of the right hand. CPT was positively correlated with age. fMRI analysis revealed significantly increased activation in the contralateral SI and ipsilateral motor cortex in elderly subjects. Furthermore, we demonstrated age-related reductions in the activity in the SII, ACC, PCC, and dorsal parts of the corpus callosum. Our study revealed dramatic age-related differences in the processing of a simple tactile stimulus in the somatosensory network. Specifically, we detected enhanced activation in the contralateral SI and ipsilateral motor cortex assumingly caused by deficient inhibition and decreased activation in later stages of somatosensory processing (SII, cingulate cortex) in elderly subjects. These results indicate that, in addition to over-activation to compensate for impaired brain functions, there are complex mechanisms of modified inhibition and excitability involved in somatosensory processing in the ageing brain.
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Klingner CM, Hasler C, Brodoehl S, Witte OW. Excitatory and inhibitory mechanisms underlying somatosensory habituation. Hum Brain Mapp 2012; 35:152-60. [PMID: 22847930 DOI: 10.1002/hbm.22163] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2012] [Revised: 04/21/2012] [Accepted: 06/19/2012] [Indexed: 11/10/2022] Open
Abstract
Habituation is a basic process of learning in which repeated exposure to a sensory stimulus leads to a decrease in the strength of neuronal activations and behavioral responses. In addition to increases in neuronal activity, sensory stimuli can also lead to decreases in neuronal activity. Until now, the effects of habituation on stimulus-induced neuronal deactivations have not been investigated. We performed functional magnetic resonance imaging in 30 healthy subjects during repetitive unilateral somatosensory stimulation and combined this analysis with a psychophysiological examination of changes in the perception threshold. Consistent with the literature, we found a time-dependent decrease of the positive blood oxygenation level-dependent (BOLD) response (indicative of habituation) in the primary somatosensory cortex (SI) contralateral to the stimulus. In contrast, the negative BOLD response (NBR) in the ipsilateral SI did not show a decrease in amplitude; instead, an increase in amplitude was found, i.e., a stronger NBR (increased response). The increased NBR was associated with an increased perception threshold of the nonstimulated hand. These findings suggest that habituation is not primarily characterized by a decrease in the neuronal response to repeated stimuli but rather a widespread change in the balance between excitatory and inhibitory effects that favors inhibitory effects.
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Klingner CM, Hasler C, Brodoehl S, Axer H, Witte OW. Perceptual plasticity is mediated by connectivity changes of the medial thalamic nucleus. Hum Brain Mapp 2012; 34:2343-52. [PMID: 22451353 DOI: 10.1002/hbm.22074] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2011] [Revised: 02/01/2012] [Accepted: 02/13/2012] [Indexed: 11/07/2022] Open
Abstract
It is well known that the threshold for somatosensory perception may adapt to different inputs. Recent studies suggest the presence of a modulating effect of somatosensory inputs on the spinal dorsal horn. However, the effects of somatosensory inputs on cerebral processing and, in particular, on the functional and effective connectivity of the somatosensory brain network, are poorly understood. In this study, we investigated the longitudinal impact of somatosensory stimuli on the resting-state functional connectivity and effective connectivity of the somatosensory brain network. We performed resting-state functional magnetic resonance imaging (fMRI) in 12 healthy subjects before and after unilateral electrical median nerve stimulation. We combined this analysis with a psychophysiological examination of changes of the perception threshold. We found that the unilateral median nerve stimulation increased the perception thresholds bilaterally and increased the resting-state functional and effective connectivity between most cortical areas of the somatosensory network. The major finding, however, was a decreased resting-state functional connectivity between both secondary somatosensory cortices and the bilateral medial nuclear complex of the thalamus. This decreased connectivity was correlated with increased perception thresholds. These findings emphasize the importance of the medial thalamic nucleus for the perceptual awareness of somatosensory stimuli.
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Affiliation(s)
- Carsten M Klingner
- Department of Neurology, Hans Berger Clinic for Neurology, University Hospital Jena, Friedrich Schiller University, Erlanger Allee 101, Jena, Germany.
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Influences of negative BOLD responses on positive BOLD responses. Neuroimage 2011; 55:1709-15. [DOI: 10.1016/j.neuroimage.2011.01.028] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Revised: 01/07/2011] [Accepted: 01/11/2011] [Indexed: 11/23/2022] Open
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Effects of fusion between tactile and proprioceptive inputs on tactile perception. PLoS One 2011; 6:e18073. [PMID: 21464943 PMCID: PMC3064587 DOI: 10.1371/journal.pone.0018073] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Accepted: 02/24/2011] [Indexed: 11/30/2022] Open
Abstract
Tactile perception is typically considered the result of cortical interpretation of afferent signals from a network of mechanical sensors underneath the skin. Yet, tactile illusion studies suggest that tactile perception can be elicited without afferent signals from mechanoceptors. Therefore, the extent that tactile perception arises from isomorphic mapping of tactile afferents onto the somatosensory cortex remains controversial. We tested whether isomorphic mapping of tactile afferent fibers onto the cortex leads directly to tactile perception by examining whether it is independent from proprioceptive input by evaluating the impact of different hand postures on the perception of a tactile illusion across fingertips. Using the Cutaneous Rabbit Effect, a well studied illusion evoking the perception that a stimulus occurs at a location where none has been delivered, we found that hand posture has a significant effect on the perception of the illusion across the fingertips. This finding emphasizes that tactile perception arises from integration of perceived mechanical and proprioceptive input and not purely from tactile interaction with the external environment.
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Klingner CM, Hasler C, Brodoehl S, Witte OW. Dependence of the negative BOLD response on somatosensory stimulus intensity. Neuroimage 2010; 53:189-95. [DOI: 10.1016/j.neuroimage.2010.05.087] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Revised: 05/27/2010] [Accepted: 05/28/2010] [Indexed: 02/04/2023] Open
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Stringer EA, Chen LM, Friedman RM, Gatenby C, Gore JC. Differentiation of somatosensory cortices by high-resolution fMRI at 7 T. Neuroimage 2010; 54:1012-20. [PMID: 20887793 DOI: 10.1016/j.neuroimage.2010.09.058] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Revised: 09/16/2010] [Accepted: 09/21/2010] [Indexed: 11/28/2022] Open
Abstract
This study aimed to evaluate the ability of BOLD signals at high MRI field (7 T) to map fine-scale single-digit activations in subdivisions (areas 3b and 1) of the human primary somatosensory cortex (SI) in individual subjects. We acquired BOLD fMRI data from cortical areas around the central suclus in six healthy human subjects while stimulating individual finger pads with 2-Hz air puffs. Discrete, single-digit responses were identified in an area along the posterior bank of the central sulcus corresponding to area 3b and in an area along the crest of the postcentral gyrus corresponding to area 1. In single subjects, activations of digits 1 to 4 in both areas 3b and 1 were organized in a somatotopic manner. The separation of digit representations was measured for adjacent digits and was approximately 1.6 times greater in area 3b than in area 1. Within individual subjects, the cortical responses to single-digit stimulations and the magnitude of the BOLD signals were reproducible across imaging runs and were comparable across subjects. Our findings demonstrate that BOLD fMRI at 7 T is capable of revealing the somatotopic organization of single-digit activations with good within-subject reliability and reproducibility, and activation maps can be acquired within a reasonably short time window, which are essential characteristics for several neurological applications within patient populations.
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Nelson AJ, Chen R. Digit somatotopy within cortical areas of the postcentral gyrus in humans. Cereb Cortex 2008; 18:2341-51. [PMID: 18245039 DOI: 10.1093/cercor/bhm257] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Characterizing the cortical representation of the body surface is fundamental to understanding the neural basis of human somatic sensation. Monkey studies benefited from the detailed somatotopic maps obtained from electrophysiology methods. Advances in noninvasive neuroimaging techniques now permit such questions to be probed in humans. The present study characterizes the detailed somatotopic representation of individual digits within subregions of the postcentral gyrus in humans using high-spatial resolution functional magnetic resonance imaging and surface-based mapping. Four areas of consistent activation included area 3b, area 2, and 2 discrete foci within area 1. Area 3b and the superior area 1 foci demonstrated an orderly somatotopic distribution for all digits of the hand, whereby the thumb was represented most lateral, anterior, and inferior and the fifth digit was most medial, posterior, and superior. Compared with area 3b, somatotopic variability was greater in area 1 and the digits spanned less cortical territory. This study additionally identified the specific digit pairs that are separable in areas 3b and 1 using current imaging methods. Somatotopy was not resolved in area 2 or in the inferior area 1 foci.
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Affiliation(s)
- Aimee J Nelson
- Division of Neurology and Krembil Neuroscience Centre, Toronto Western Research Institute, University of Toronto, Toronto, Ontario, Canada
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Taskin B, Holtze S, Krause T, Villringer A. Inhibitory impact of subliminal electrical finger stimulation on SI representation and perceptual sensitivity of an adjacent finger. Neuroimage 2007; 39:1307-13. [PMID: 18024161 DOI: 10.1016/j.neuroimage.2007.09.039] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2007] [Revised: 08/15/2007] [Accepted: 09/25/2007] [Indexed: 11/16/2022] Open
Abstract
Simultaneous stimulation of two adjacent fingers above sensory perception threshold (supraliminal stimulation) leads to an inhibitory interaction effect on responses in primary somatosensory cortex (SI). Moreover, during electrical finger stimulation closely below threshold for conscious perception (subliminal stimulation) inhibitory interneurons in cortical layer 4 are assumed to be activated preferentially as compared to excitatory interneurons. Using fMRI in humans, here we show that interspersed subliminal electrical stimulation of an adjacent finger reduces the response to target finger stimulation in contralateral SI. This effect was shown in a complementary study to be associated behaviorally with a diminished detectability of test pulses on the target finger. We propose the mechanism underlying this lateral inhibitory effect to be related to a representational overlap of inhibitory interneurons in SI based on the divergence of thalamocortical feedforward projections, or to intracortical lateral inhibitory projections targeting juxtaposed receptive fields, or both.
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Affiliation(s)
- Birol Taskin
- Neurologische Klinik und Poliklinik, Charité-Universitätsmedizin Berlin, Campus Charité Mitte, Berlin NeuroImaging Center, Charitéplatz 1, 10117 Berlin, Germany.
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Fiehler K, Burke M, Engel A, Bien S, Rösler F. Kinesthetic Working Memory and Action Control within the Dorsal Stream. Cereb Cortex 2007; 18:243-53. [PMID: 17548801 DOI: 10.1093/cercor/bhm071] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
There is wide agreement that the "dorsal (action) stream" processes visual information for movement control. However, movements depend not only on vision but also on tactile and kinesthetic information (=haptics). Using functional magnetic resonance imaging, the present study investigates to what extent networks within the dorsal stream are also utilized for kinesthetic action control and whether they are also involved in kinesthetic working memory. Fourteen blindfolded participants performed a delayed-recognition task in which right-handed movements had to be encoded, maintained, and later recognized without any visual feedback. Encoding of hand movements activated somatosensory areas, superior parietal lobe (dorsodorsal stream), anterior intraparietal sulcus (aIPS) and adjoining areas (ventrodorsal stream), premotor cortex, and occipitotemporal cortex (ventral stream). Short-term maintenance of kinesthetic information elicited load-dependent activity in the aIPS and adjacent anterior portion of the superior parietal lobe (ventrodorsal stream) of the left hemisphere. We propose that the action representation system of the dorsodorsal and ventrodorsal stream is utilized not only for visual but also for kinesthetic action control. Moreover, the present findings demonstrate that networks within the ventrodorsal stream, in particular the left aIPS and closely adjacent areas, are also engaged in working memory maintenance of kinesthetic information.
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Affiliation(s)
- Katja Fiehler
- Department of Experimental and Biological Psychology, Philipps-Universität Marburg, Gutenbergstr. 18, D-35032 Marburg, Germany.
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