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Saito H, Yazawa S, Shinozaki J, Murahara T, Shiraishi H, Matsuhashi M, Nagamine T. Appraisal of definition of baseline length for somatosensory evoked magnetic fields. J Neurosci Methods 2021; 359:109213. [PMID: 33951455 DOI: 10.1016/j.jneumeth.2021.109213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 04/16/2021] [Accepted: 04/29/2021] [Indexed: 11/17/2022]
Abstract
BACKGROUND The baseline (BL) segment in the prestimulus period is generally assigned as a reference of evoked activities. However, an experimenter empirically defines its length in each condition. So far, the criterion for the length of a BL segment has not been established. NEW METHOD We evaluated the effect of the length of the BL segment by recording somatosensory evoked magnetic fields (SEFs) under fixed stimulus onset asynchrony (SOA). For the evaluation of the length of the BL segment in the prestimulus period, five proportions in relation to SOA were used as the BL segment. In addition, we adopted other two types of BL segment which were the single data point measured from the value of stimulus onset (BL0) and the mean value of the whole raw data throughout the recording (DC mean). We investigated the influence of the BL segments on SEFs by utilizing two indicators: normalized N20 m amplitudes and estimated locations of corresponding equivalent current dipoles (ECDs). RESULTS Both indicators did not show any significant differences, based on the factor of BL segments, in any SOA conditions. COMPARISON WITH EXISTING METHOD The BL0 had by far the largest variation in the ECD locations.Therefore, utilizing stimulus onset as the BL segment should be avoided. In addition, considering that other BL segments provided comparable values by the two indicators, the DC mean can reasonably be adopted. CONCLUSIONS We suggest that utilizing the DC mean could be employed as the BL segment.
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Affiliation(s)
- Hidekazu Saito
- Department of Systems Neuroscience, School of Medicine, Sapporo Medical University, South 1, West 17, Chuo-ku, Sapporo, 060-8556, Japan; Department of Occupational Therapy, School of Health Sciences, Sapporo Medical University, South 1, West 17, Chuo-ku, Sapporo, 060-8556, Japan.
| | - Shogo Yazawa
- Department of Systems Neuroscience, School of Medicine, Sapporo Medical University, South 1, West 17, Chuo-ku, Sapporo, 060-8556, Japan.
| | - Jun Shinozaki
- Department of Systems Neuroscience, School of Medicine, Sapporo Medical University, South 1, West 17, Chuo-ku, Sapporo, 060-8556, Japan.
| | - Takashi Murahara
- Department of Systems Neuroscience, School of Medicine, Sapporo Medical University, South 1, West 17, Chuo-ku, Sapporo, 060-8556, Japan.
| | - Hideaki Shiraishi
- Department of Pediatrics, Hokkaido University School of Medicine, North 15, West 7, Kita-ku, Sapporo, 060-8638, Japan.
| | - Masao Matsuhashi
- Department of Epilepsy, Movement Disorders and Physiology, Kyoto University School of Medicine, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan.
| | - Takashi Nagamine
- Department of Systems Neuroscience, School of Medicine, Sapporo Medical University, South 1, West 17, Chuo-ku, Sapporo, 060-8556, Japan.
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Naganuma R, Yabe I, Takeuchi M, Morishita K, Nakane S, Takase R, Takahashi-Iwata I, Matsushima M, Otsuki M, Shiraishi H, Sasaki H. Clinical factors affecting evoked magnetic fields in patients with Parkinson's disease. PLoS One 2020; 15:e0232808. [PMID: 32941428 PMCID: PMC7498017 DOI: 10.1371/journal.pone.0232808] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Accepted: 08/31/2020] [Indexed: 11/19/2022] Open
Abstract
Studies on evoked responses in Parkinson's disease (PD) may be useful for elucidating the etiology and quantitative evaluation of PD. However, in previous studies, the association between evoked responses and detailed motor symptoms or cognitive functions has not been clear. This study investigated the characteristics of the visual (VEF), auditory (AEF), and somatosensory (SEF) evoked magnetic fields in patients with Parkinson’s disease (PD), and the correlations between evoked fields and the patient’s clinical characteristics, motor symptoms, and cognitive functions. Twenty patients with PD and 10 healthy controls (HCs) were recruited as participants. We recorded VEF, AEF, and SEF, collected clinical characteristics, performed physical examinations, and administered 10 cognitive tests. We investigated differences in the latencies of the evoked fields between patients with PD and HCs. We also evaluated the correlation of the latencies with motor symptoms and cognitive functioning. There were significant differences between the two groups in 6 of the cognitive tests, all of which suggested mild cognitive impairment in patients with PD. The latencies of the VEF N75m, P100m, N145m, AEF P50m, P100m, and SEF P60m components were greater in the patients with PD than in the HCs. The latencies mainly correlated with medication and motor symptoms, less so with cognitive tests, with some elements of the correlations remaining significant after Bonferroni correction. In conclusion, the latencies of the VEF, AEF, and SEF were greater in PD patients than in HCs and were mainly correlated with medication and motor symptoms rather than cognitive functioning. Findings from this study suggest that evoked fields may reflect basal ganglia functioning and are candidates for assessing motor symptoms or the therapeutic effects of medication in patients with PD.
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Affiliation(s)
- Ryoji Naganuma
- Department of Neurology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Ichiro Yabe
- Department of Neurology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
- * E-mail:
| | - Megumi Takeuchi
- Department of Neurology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Kirari Morishita
- Division of Laboratory and Transfusion Medicine, Hokkaido University Hospital, Sapporo, Hokkaido, Japan
| | - Shingo Nakane
- Division of Magnetoencephalography, Hokkaido University Hospital, Sapporo, Hokkaido, Japan
| | - Ryoken Takase
- Faculty of Health Sciences/Graduate School of Health Sciences/Department of Health Sciences, School of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
- Department of Radiation Technology, Sapporo City General Hospital, Sapporo, Hokkaido, Japan
| | - Ikuko Takahashi-Iwata
- Department of Neurology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Masaaki Matsushima
- Department of Neurology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Mika Otsuki
- Faculty of Health Sciences/Graduate School of Health Sciences/Department of Health Sciences, School of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Hideaki Shiraishi
- Department of Pediatrics, Hokkaido University Hospital, Sapporo, Hokkaido, Japan
| | - Hidenao Sasaki
- Department of Neurology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
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Mirror imaging of finger mechanical stimulation affects secondary somatosensory response. Neuroreport 2018; 29:229-234. [PMID: 29303841 DOI: 10.1097/wnr.0000000000000966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The aim of this study was to investigate the effect of finger-tip touch on the somatosensory cortex under mirror imaging conditions. Magnetoencephalographic recordings of somatosensory-evoked field responses to mechanical tactile stimulation of the index finger in both hands were obtained for the right-handed healthy participants as part of the following mirror or nonmirror tasks. Both hands were screened and mechanical stimuli were delivered to the right index finger pulp. A mirror was placed in front of the patient with the right hand facing the reflective surface, as if it were the left side (mirror task). Another task comprised the screening of right hands behind a partition, after which mechanical stimuli were delivered to the right index finger pulp without a mirror (nonmirror task). The same tasks for the left hand were also examined. The estimated current dipoles were identified and analyzed. In the measurements following all the tasks, the equivalent current dipoles (ECDs) were estimated in the corresponding contralateral primary somatosensory area (cSI). The other ECDs were estimated in the secondary somatosensory area both contralateral (cSII) and ipsilateral (iSII) to the stimulus side. The amplitudes of ECDs in the cSII area following the left index stimuli in the mirror task were significantly larger than those in the nonmirror task (P=0.043). The mirror effect on the somatosensory cortex in this study may be small, but a positive variation was shown in the form of a response to the actual stimulation in the hand opposite to the hand which was hidden behind the mirror.
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Onishi H, Sugawara K, Yamashiro K, Sato D, Kirimoto H, Tamaki H, Shirozu H, Kameyama S. Inhibitory effect of intensity and interstimulus interval of conditioning stimuli on somatosensory evoked magnetic fields. Eur J Neurosci 2016; 44:2104-13. [PMID: 27319980 DOI: 10.1111/ejn.13317] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 06/14/2016] [Accepted: 06/16/2016] [Indexed: 10/21/2022]
Abstract
Magnetoencephalography (MEG) recordings were performed to investigate the inhibitory effects of conditioning stimuli with various types of interstimulus intervals (ISIs) or intensities on somatosensory evoked magnetic fields (SEFs) using a 306-ch whole-head MEG system. Twenty-three healthy volunteers participated in this study. Electrical stimuli were applied to the right median nerve at the wrist. Six pulse trains with ISIs of 500 ms were presented in Experiment 1. A paired-pulse paradigm with three kinds of conditioning stimulus (CON) intensities, 500 ms before the test stimulus (TS), was applied in Experiment 2. Finally, three CONs 500 or 1000 ms before TS were presented in Experiment 3. Three main SEF deflections (N20m, P35m, and P60m) were observed, and the source activities of P35m and P60m significantly decreased after the 2nd pulse of a six pulse trains. These source activities also significantly decreased with increasing intensity of CON. In addition, these attenuations of source activities were affected by CON-CON or CON-TS intervals. These results indicated that the source activities were modulated by the intensity and ISIs of CONs. Furthermore, P35m after the stimulation were very sensitive to CONs; however, the attenuation of P60m after the stimulation lasted for a longer period than that of P35m. Our findings suggest that the conditioning stimulation had inhibitory effects on subsequent evoked cortical responses for more than 500 ms. Our results also provide important clues about the nature of short-latency somatosensory responses in human studies.
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Affiliation(s)
- Hideaki Onishi
- Institute for human movement and medical sciences, Niigata University of Health and Welfare, 1398 Shimami-cho, Kita-ku, Niigata, 950-3198, Japan
| | - Kazuhiro Sugawara
- Institute for human movement and medical sciences, Niigata University of Health and Welfare, 1398 Shimami-cho, Kita-ku, Niigata, 950-3198, Japan
| | - Koya Yamashiro
- Institute for human movement and medical sciences, Niigata University of Health and Welfare, 1398 Shimami-cho, Kita-ku, Niigata, 950-3198, Japan
| | - Daisuke Sato
- Institute for human movement and medical sciences, Niigata University of Health and Welfare, 1398 Shimami-cho, Kita-ku, Niigata, 950-3198, Japan
| | - Hikari Kirimoto
- Institute for human movement and medical sciences, Niigata University of Health and Welfare, 1398 Shimami-cho, Kita-ku, Niigata, 950-3198, Japan
| | - Hiroyuki Tamaki
- Institute for human movement and medical sciences, Niigata University of Health and Welfare, 1398 Shimami-cho, Kita-ku, Niigata, 950-3198, Japan
| | - Hiroshi Shirozu
- Department of Neurosurgery, Nishi-Niigata Chuo National Hospital, Niigata, Japan
| | - Shigeki Kameyama
- Department of Neurosurgery, Nishi-Niigata Chuo National Hospital, Niigata, Japan
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Kojima S, Onishi H, Sugawara K, Miyaguchi S, Kirimoto H, Tamaki H, Shirozu H, Kameyama S. No relation between afferent facilitation induced by digital nerve stimulation and the latency of cutaneomuscular reflexes and somatosensory evoked magnetic fields. Front Hum Neurosci 2014; 8:1023. [PMID: 25566038 PMCID: PMC4274984 DOI: 10.3389/fnhum.2014.01023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Accepted: 12/04/2014] [Indexed: 11/13/2022] Open
Abstract
Primary motor cortex (M1) excitability can be assessed using transcranial magnetic stimulation (TMS) and can be modulated by a conditioning electrical stimulus delivered to a peripheral nerve prior to TMS. This is known as afferent facilitation (AF). The aim of this study was to determine whether AF can be induced by digital nerve stimulation and to evaluate the relation between the interstimulus interval (ISI) required for AF and the latency of the E2 component of the cutaneomuscular reflex (CMR) and the prominent somatosensory evoked field (SEF) deflection that occurs approximately 70 ms after digital nerve stimulation (P60m). Stimulation of the digital nerve of the right index finger was followed, at various time intervals, by single-pulse TMS applied to the contralateral hemisphere. The ISI between digital nerve stimulation and TMS was 20, 30, 40, 50, 60, 70, 80, 100, 140, 180, 200, or 220 ms. Single-pulse TMS was performed alone as a control. SEFs were recorded following digital nerve stimulation of the index finger, and the equivalent current dipole of prominent deflections that occurred around 70 ms after the stimulation was calculated. CMRs were recorded following digital nerve stimulation during muscle contraction. Motor evoked potentials (MEPs) were facilitated at an ISI between 50 and 100 ms in 11 of 13 subjects, and the facilitated MEP amplitude was larger than the unconditioned MEP amplitude (p < 0.01). There was no significant correlation between the ISI at which AF was maximal and the latency of the P60m component of the SEF (r = −0.50, p = 0.12) or the E2 component of the CMR (r = −0.54, p = 0.88). These results indicate that the precise ISI required for AF cannot be predicted using SEF or CMR.
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Affiliation(s)
- Sho Kojima
- Graduate School of Health and Welfare, Niigata University of Health and Welfare Niigata City, Niigata, Japan ; Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare Niigata City, Niigata, Japan ; Tokyo Bay Rehabilitation Hospital Narashino City, Chiba, Japan
| | - Hideaki Onishi
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare Niigata City, Niigata, Japan
| | - Kazuhiro Sugawara
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare Niigata City, Niigata, Japan
| | - Shota Miyaguchi
- Graduate School of Health and Welfare, Niigata University of Health and Welfare Niigata City, Niigata, Japan ; Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare Niigata City, Niigata, Japan
| | - Hikari Kirimoto
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare Niigata City, Niigata, Japan
| | - Hiroyuki Tamaki
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare Niigata City, Niigata, Japan
| | - Hiroshi Shirozu
- Department of Neurosurgery, Nishi-Niigata Chuo National Hospital Niigata City, Niigata, Japan
| | - Shigeki Kameyama
- Department of Neurosurgery, Nishi-Niigata Chuo National Hospital Niigata City, Niigata, Japan
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Bradley C, Joyce N, Garcia-Larrea L. Adaptation in human somatosensory cortex as a model of sensory memory construction: a study using high-density EEG. Brain Struct Funct 2014; 221:421-31. [DOI: 10.1007/s00429-014-0915-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 10/14/2014] [Indexed: 11/29/2022]
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7
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Onishi H, Sugawara K, Yamashiro K, Sato D, Suzuki M, Kirimoto H, Tamaki H, Murakami H, Kameyama S. Effect of the number of pins and inter-pin distance on somatosensory evoked magnetic fields following mechanical tactile stimulation. Brain Res 2013; 1535:78-88. [DOI: 10.1016/j.brainres.2013.08.048] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 08/23/2013] [Accepted: 08/24/2013] [Indexed: 11/26/2022]
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8
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Lim M, Kim JS, Chung CK. Modulation of somatosensory evoked magnetic fields by intensity of interfering stimuli in human somatosensory cortex: An MEG study. Neuroimage 2012; 61:660-9. [DOI: 10.1016/j.neuroimage.2012.04.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Revised: 03/12/2012] [Accepted: 04/02/2012] [Indexed: 10/28/2022] Open
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Wühle A, Preissl H, Braun C. Cortical processing of near-threshold tactile stimuli in a paired-stimulus paradigm--an MEG study. Eur J Neurosci 2011; 34:641-51. [PMID: 21749492 DOI: 10.1111/j.1460-9568.2011.07770.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In the present magnetoencephalography study, we applied a paired-stimulus paradigm to study the weak cortical responses evoked by near-threshold tactile prime stimuli by means of their attenuating effect on the cortical responses evoked by subsequently applied above-threshold test stimuli. In stimulus pairs with adequate interstimulus intervals (ISIs), the extent of test stimulus response attenuation is related to the amplitude of prime stimulus responses, and the duration of the attenuating effect indicates how long memory traces of a prime stimulus reside in cortical areas. We hypothesized that the attenuation of test stimulus responses, studied for ISIs of 30, 60 and 150 ms, would provide insight into the temporal dynamics of near-threshold stimulus processing in primary (SI) and secondary somatosensory cortex (SII), and reveal differences in response amplitude due to conscious perception. Attenuation of test stimulus responses in SI was observed for ISIs up to 60 ms, whereas in SII the effect outlasted the ISI of 150 ms. Differences due to conscious perception of the near-threshold stimuli were only observed in SII with stronger attenuation for perceived than for missed near-threshold stimuli. Applying this indirect approach to near-threshold stimulus processing, we could show that the extent and duration of response attenuation is related to prime stimulus processing and differential temporal and functional characteristics of near-threshold stimulus information processing in SI and SII: transient processing of basic stimulus information not sufficient for conscious perception in SI and long-lasting activations involving conscious perception in SII.
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Affiliation(s)
- Anja Wühle
- MEG Center, University of Tübingen, Tübingen, Germany.
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10
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Targeting the Mammalian Target of Rapamycin (mTOR) in Cancer Therapy: Lessons from Past and Future Perspectives. Cancers (Basel) 2011; 3:2478-500. [PMID: 24212820 PMCID: PMC3757428 DOI: 10.3390/cancers3022478] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Revised: 05/13/2011] [Accepted: 05/16/2011] [Indexed: 12/13/2022] Open
Abstract
Over the last decade, extensive studies have been made to understand the role played by the mammalian target of rapamycin (mTOR) in cancer. Knowledge in this field has been gained from discoveries in basic research as well as from observations made in patients treated with allosteric mTOR inhibitors such as rapamycin. Despite promising preclinical studies, targeting mTOR in cancer therapy has shown limited clinical benefits so far. However, recent findings have revealed the complexity of the functions of mTOR in cancer and have helped develop new strategies to improve the anticancer efficacy of mTOR inhibitors. In particular, a complex network between mTOR and other signaling pathways has been identified that influences the anticancer efficacy of mTOR inhibitors. In addition, an emerging role of mTOR in the tumor microenvironment has been suggested. In this review, we confront the major findings that have been made in the past, both in experimental settings as well as in clinical trials. We further review the strategies that have been designed to further improve the efficacy of therapies targeting mTOR.
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11
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Onishi H, Oyama M, Soma T, Kirimoto H, Sugawara K, Murakami H, Kameyama S. Muscle-afferent projection to the sensorimotor cortex after voluntary movement and motor-point stimulation: An MEG study. Clin Neurophysiol 2011; 122:605-610. [DOI: 10.1016/j.clinph.2010.07.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Revised: 06/17/2010] [Accepted: 07/09/2010] [Indexed: 10/19/2022]
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12
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Using Objective Response Detection techniques for detecting the tibial somatosensory evoked response with different stimulation rates. J Neurosci Methods 2011; 195:255-60. [DOI: 10.1016/j.jneumeth.2010.12.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2010] [Revised: 12/01/2010] [Accepted: 12/02/2010] [Indexed: 10/18/2022]
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Zumer JM, Nagarajan SS, Krubitzer LA, Zhu Z, Turner RS, Disbrow EA. MEG in the macaque monkey and human: distinguishing cortical fields in space and time. Brain Res 2010; 1345:110-24. [PMID: 20493828 DOI: 10.1016/j.brainres.2010.05.037] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2010] [Revised: 05/01/2010] [Accepted: 05/12/2010] [Indexed: 11/29/2022]
Abstract
Magnetoencephalography (MEG) is an increasingly popular non-invasive tool used to record, on a millisecond timescale, the magnetic field changes generated by cortical neural activity. MEG has the advantage, over fMRI for example, that it is a direct measure of neural activity. In the current investigation we used MEG to measure cortical responses to tactile and auditory stimuli in the macaque monkey. We had two aims. First, we sought to determine whether MEG, a technique that may have low spatial accuracy, could be used to distinguish the location and organization of sensory cortical fields in macaque monkeys, a species with a relatively small brain compared to that of the human. Second, we wanted to examine the temporal dynamics of cortical responses in the macaque monkey relative to the human. We recorded MEG data from anesthetized monkeys and, for comparison, from awake humans that were presented with simple tactile and auditory stimuli. Neural source reconstruction of MEG data showed that primary somatosensory and auditory cortex could be differentiated and, further, that separate representations of the digit and lip within somatosensory cortex could be identified in macaque monkeys as well as humans. We compared the latencies of activity from monkey and human data for the three stimulation types and proposed a correspondence between the neural responses of the two species. We thus demonstrate the feasibility of using MEG in the macaque monkey and provide a non-human primate model for examining the relationship between external evoked magnetic fields and their underlying neural sources.
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Affiliation(s)
- Johanna M Zumer
- Department of Radiology, University of California, San Francisco, CA, USA
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Wühle A, Mertiens L, Rüter J, Ostwald D, Braun C. Cortical processing of near-threshold tactile stimuli: an MEG study. Psychophysiology 2010; 47:523-34. [PMID: 20210878 DOI: 10.1111/j.1469-8986.2010.00964.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In the present study we tested the applicability of a paired-stimulus paradigm for the investigation of near-threshold (NT) stimulus processing in the somatosensory system using magnetoencephalography. Cortical processing of the NT stimuli was studied indirectly by investigating the impact of NT stimuli on the source activity of succeeding suprathreshold test stimuli. We hypothesized that cortical responses evoked by test stimuli are reduced due to the preactivation of the same finger representation by the preceding NT stimulus. We observed attenuation of the magnetic responses in the secondary somatosensory (SII) cortex, with stronger decreases for perceived than for missed NT stimuli. Our data suggest that processing in the primary somatosensory cortex including recovery lasts for <200 ms. Conversely, the occupancy of SII lasts >/=500 ms, which points to its role in temporal integration and conscious perception of sensory input.
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Affiliation(s)
- Anja Wühle
- MEG Center, University of Tübingen, Tübingen, Germany
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Zhu Z, Zumer JM, Lowenthal ME, Padberg J, Recanzone GH, Krubitzer LA, Nagarajan SS, Disbrow EA. The relationship between magnetic and electrophysiological responses to complex tactile stimuli. BMC Neurosci 2009; 10:4. [PMID: 19146670 PMCID: PMC2652466 DOI: 10.1186/1471-2202-10-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Accepted: 01/15/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Magnetoencephalography (MEG) has become an increasingly popular technique for non-invasively characterizing neuromagnetic field changes in the brain at a high temporal resolution. To examine the reliability of the MEG signal, we compared magnetic and electrophysiological responses to complex natural stimuli from the same animals. We examined changes in neuromagnetic fields, local field potentials (LFP) and multi-unit activity (MUA) in macaque monkey primary somatosensory cortex that were induced by varying the rate of mechanical stimulation. Stimuli were applied to the fingertips with three inter-stimulus intervals (ISIs): 0.33s, 1s and 2s. RESULTS Signal intensity was inversely related to the rate of stimulation, but to different degrees for each measurement method. The decrease in response at higher stimulation rates was significantly greater for MUA than LFP and MEG data, while no significant difference was observed between LFP and MEG recordings. Furthermore, response latency was the shortest for MUA and the longest for MEG data. CONCLUSION The MEG signal is an accurate representation of electrophysiological responses to complex natural stimuli. Further, the intensity and latency of the MEG signal were better correlated with the LFP than MUA data suggesting that the MEG signal reflects primarily synaptic currents rather than spiking activity. These differences in latency could be attributed to differences in the extent of spatial summation and/or differential laminar sensitivity.
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Affiliation(s)
- Zhao Zhu
- Biomagnetic Imaging Laboratory, Department of Radiology, University of California San Francisco, San Francisco, CA 94143-0628, USA.
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Sakamoto K, Nakata H, Kakigi R. Somatosensory-evoked magnetic fields following stimulation of the tongue in humans. Clin Neurophysiol 2008; 119:1664-73. [DOI: 10.1016/j.clinph.2008.03.029] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2007] [Revised: 02/26/2008] [Accepted: 03/25/2008] [Indexed: 11/28/2022]
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17
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Contarino MF, Kruisdijk JJM, Koster L, Ongerboer de Visser BW, Speelman JD, Koelman JHTM. Sensory integration in writer's cramp: comparison with controls and evaluation of botulinum toxin effect. Clin Neurophysiol 2007; 118:2195-206. [PMID: 17709294 DOI: 10.1016/j.clinph.2007.07.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2006] [Revised: 06/28/2007] [Accepted: 07/04/2007] [Indexed: 01/08/2023]
Abstract
OBJECTIVE Abnormal temporal and spatial sensory integration have been described in mixed groups of dystonic patients. We tested somatosensory integration and the effect of botulinum toxin (BoNT) in patients with writer's cramp (WC). METHODS Median and ulnar SEPs were recorded in 29 WC patients and in 10 controls. We performed: individual and simultaneous stimulation of median and ulnar nerves (MU) and paired stimulation of median nerve at interstimulus-interval (ISI) of 40 and 100 ms. All the trials were repeated after blinded randomized treatment with placebo or BoNT-A. RESULTS We found no differences between patients and controls in standard SEPs. Spatial (except for N9) and temporal suppression after ISI 40 were present in both groups for all the waves; after ISI 100, suppression was present only for N70. There were no differences between patients and controls. After BoNT-A treatment, no changes were observed. CONCLUSIONS In contrast with previous findings in heterogeneous dystonic groups, and although some studies suggest impairment of spatial and temporal sensory discrimination in patients with focal dystonia, in our large cohort of patients with WC we found no evidence of abnormal somatosensory integration investigated by means of SEPs and no changes in somatosensory variables after BoNT-A treatment. SIGNIFICANCE Our findings may suggest pathophysiological differences between focal and generalized dystonia, and may also point to an inferior sensitivity of SEPs in detecting abnormalities in sensory discrimination as compared to methods based on subjective discrimination.
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Affiliation(s)
- M F Contarino
- Department of Neurology and Clinical Neurophysiology, Academic Medical Centre, University of Amsterdam, H2-222, PO Box 22660, 1100 DD Amsterdam, The Netherlands
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Wasaka T, Kida T, Nakata H, Akatsuka K, Kakigi R. Characteristics of sensori-motor interaction in the primary and secondary somatosensory cortices in humans: a magnetoencephalography study. Neuroscience 2007; 149:446-56. [PMID: 17869442 DOI: 10.1016/j.neuroscience.2007.07.040] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2007] [Revised: 07/25/2007] [Accepted: 07/26/2007] [Indexed: 11/30/2022]
Abstract
We studied sensori-motor interaction in the primary (SI) and secondary somatosensory cortex (SII) using magnetoencephalography. Since SII in both hemispheres was activated following unilateral stimulation, we analyzed SIIc (contralateral to stimulation) as well as SIIi (ipsilateral to stimulation). Four tasks were performed in human subjects in which a voluntary thumb movement of the left or right hand was combined with electrical stimulation applied to the index finger of the left or right hand: L(M)-L(S) (movement of the left thumb triggered stimulation to the left finger), L(M)-R(S) (movement of the left thumb triggered electrical stimulation to the right finger), R(M)-R(S) (movement of the right thumb triggered electrical stimulation to the right finger), and R(M)-L(S) (movement of the right thumb triggered electrical stimulation to the left finger). Stimulation to the index finger only (S condition) was also recorded. In SI, the amplitude of N20m and P35m was significantly attenuated in the R(M)-R(S) and L(M)-L(S) tasks compared with the S condition, but that for other tasks showed no change, corresponding to a conventional gating phenomenon. In SII, the R(M)-L(S) task significantly enhanced the amplitude of SIIc but reduced that of SIIi compared with the S condition. The L(M)-L(S) and R(M)-R(S) tasks caused a significant enhancement only in SIIi. The L(M)-R(S) task enhanced the amplitude only in SIIc. The laterality index showed that SII modulation with voluntary movement was more dominant in the hemisphere ipsilateral to movement but was not affected by the side of stimulation. These results provided the characteristics of activities in somatosensory cortices, a simple inhibition in SI but complicated changes in SII depending on the side of movement and stimulation, which may indicate the higher cognitive processing in SII.
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Affiliation(s)
- T Wasaka
- Department of Integrative Physiology, National Institute for Physiological Sciences, Myodaiji, Okazaki, 444-8585, Japan.
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Spatiotemporal integration of tactile information in human somatosensory cortex. BMC Neurosci 2007; 8:21. [PMID: 17359544 PMCID: PMC1838913 DOI: 10.1186/1471-2202-8-21] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2006] [Accepted: 03/14/2007] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Our goal was to examine the spatiotemporal integration of tactile information in the hand representation of human primary somatosensory cortex (anterior parietal somatosensory areas 3b and 1), secondary somatosensory cortex (S2), and the parietal ventral area (PV), using high-resolution whole-head magnetoencephalography (MEG). To examine representational overlap and adaptation in bilateral somatosensory cortices, we used an oddball paradigm to characterize the representation of the index finger (D2; deviant stimulus) as a function of the location of the standard stimulus in both right- and left-handed subjects. RESULTS We found that responses to deviant stimuli presented in the context of standard stimuli with an interstimulus interval (ISI) of 0.33 s were significantly and bilaterally attenuated compared to deviant stimulation alone in S2/PV, but not in anterior parietal cortex. This attenuation was dependent upon the distance between the deviant and standard stimuli: greater attenuation was found when the standard was immediately adjacent to the deviant (D3 and D2 respectively), with attenuation decreasing for non-adjacent fingers (D4 and opposite D2). We also found that cutaneous mechanical stimulation consistently elicited not only a strong early contralateral cortical response but also a weak ipsilateral response in anterior parietal cortex. This ipsilateral response appeared an average of 10.7 +/- 6.1 ms later than the early contralateral response. In addition, no hemispheric differences either in response amplitude, response latencies or oddball responses were found, independent of handedness. CONCLUSION Our findings are consistent with the large receptive fields and long neuronal recovery cycles that have been described in S2/PV, and suggest that this expression of spatiotemporal integration underlies the complex functions associated with this region. The early ipsilateral response suggests that anterior parietal fields also receive tactile input from the ipsilateral hand. The lack of a hemispheric difference in responses to digit stimulation supports a lack of any functional asymmetry in human somatosensory cortex.
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Akatsuka K, Wasaka T, Nakata H, Kida T, Hoshiyama M, Tamura Y, Kakigi R. Objective examination for two-point stimulation using a somatosensory oddball paradigm: An MEG study. Clin Neurophysiol 2007; 118:403-11. [PMID: 17095288 DOI: 10.1016/j.clinph.2006.09.030] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2006] [Revised: 09/17/2006] [Accepted: 09/26/2006] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To establish an objective two-point discrimination test using magnetoencephalography (MEG). METHODS First, we determined the discrimination threshold (DT) of the two-points. In the first experiment, we applied 0.9DT as standard stimuli, and 0.8DT, 1.1DT and 2DT as deviant stimuli in Conditions 1, 2 and 3, respectively. In the second experiment, we used 2DT and 0.9DT as the standard and deviant stimuli, respectively, in Condition 1. We applied two-stimuli that subjects felt as definitely one point or two-points in Condition 2 and 3, respectively. RESULTS In the first experiment, the components peaking around 30-70 and 150-250ms following deviant stimuli were significantly larger than those following standard stimuli. Considering the peak latency, these components seem consistent with the magnetic mismatch field (MMF). In the second experiment, the MMF was recorded only in Condition 1. Therefore, it is considered that the MMF was recorded only when subjects automatically discriminate one point from two-points stimuli. CONCLUSIONS This novel method can be used in neurophysiological two-point discrimination tests without the need to rely on the examiners' skills and subjects' reactions. SIGNIFICANCE We confirmed that our new method could be used for the objective examination of two-point spatial discrimination.
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Affiliation(s)
- Kosuke Akatsuka
- Department of Integrative Physiology, National Institute for Physiological Sciences, Okazaki, Japan.
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21
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Nangini C, Ross B, Tam F, Graham SJ. Magnetoencephalographic study of vibrotactile evoked transient and steady-state responses in human somatosensory cortex. Neuroimage 2006; 33:252-62. [PMID: 16884928 DOI: 10.1016/j.neuroimage.2006.05.045] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2006] [Revised: 05/26/2006] [Accepted: 05/30/2006] [Indexed: 10/24/2022] Open
Abstract
Somatosensory responses to vibrotactile stimulation applied to the index fingertip were recorded with whole-head MEG in eleven healthy young adult participants. Stimulus trains were produced by a pneumatically driven membrane oscillating at 22 Hz for a trial duration of 1 s, separated by interstimulus intervals (ISIs) of 0.5, 1.0, 3.0, and 7.0 s. Data analysis was performed in two frequency bands. Transient onset responses in the lower frequency band (<20 Hz) contained a clearly expressed P50 component. The higher frequency band (18-30 Hz) revealed a gamma-band response (GBR) within the first 200 ms followed by rhythmic activity at the stimulus frequency that continued throughout the stimulus duration, known as the steady-state response (SSR). Dipoles associated with the transient responses and SSRs were localized in two distinct regions within the primary somatosensory cortex (SI), with transient responses located on average 3 mm more medial and inferior than the SSRs. The transient and GBR peak amplitudes increased with ISI, whereas the SSR amplitude showed no ISI dependence. These results may reflect functionally and spatially distinct neural populations. Further investigations are required to assess the implications of these findings for probing the somatosensory system using other functional neuroimaging methods such as fMRI.
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Affiliation(s)
- C Nangini
- Department of Medical Biophysics, University of Toronto, ON, Canada.
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Huttunen J, Komssi S, Lauronen L. Spatial dynamics of population activities at S1 after median and ulnar nerve stimulation revisited: An MEG study. Neuroimage 2006; 32:1024-31. [PMID: 16777434 DOI: 10.1016/j.neuroimage.2006.04.196] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2005] [Revised: 02/28/2006] [Accepted: 04/18/2006] [Indexed: 11/29/2022] Open
Abstract
In a number of studies, magnetoencephalography (MEG) has been successfully employed in localizing cortical neural population activities after stimulation of peripheral nerves. Little attention has been paid, however, to the spatiotemporal dynamics of these activations within the primary somatosensory cortex (SI). Here we report on the activation sequence at the right SI after left median and ulnar nerve stimulation. The results show that at least three macroscopically separable sources within or near SI are activated within 100 ms after the stimulus, corresponding to the somatosensory evoked field (SEF) deflections N20m, P35m and P60m. As P60m was localized significantly more posteriorly and also tended to be deeper than the two earlier deflections, its underlying source may be more extensive than during N20m and P35m, and it may get contribution from the postcentral gyrus and sulcus, possibly Brodmann areas 1 and 2. The source separation between the neural populations activated by the 2 nerves was 12 mm during N20m, 6 mm during P35m and 4 mm during P60m. Thus, at longer latencies, the centers of gravity of the activations were closer to each other for the 2 nerves. We argue that this reflects spreading of the activation with time from the site of initial excitation to encompass larger and more overlapping neural populations at longer latencies.
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Affiliation(s)
- Juha Huttunen
- BioMag Laboratory, Engineering Centre, Helsinki University Central Hospital, FIN-00029 Helsinki, Finland.
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Wasaka T, Nakata H, Akatsuka K, Kida T, Inui K, Kakigi R. Differential modulation in human primary and secondary somatosensory cortices during the preparatory period of self-initiated finger movement. Eur J Neurosci 2005; 22:1239-47. [PMID: 16176367 DOI: 10.1111/j.1460-9568.2005.04289.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
To elucidate the mechanisms underlying sensorimotor integration, we investigated modulation in the primary (SI) and secondary (SII) somatosensory cortices during the preparatory period of a self-initiated finger extension. Electrical stimulation of the right median nerve was applied continuously, while the subjects performed a self-initiated finger extension and were instructed not to pay attention to the stimulation. The preparatory period was divided into five sub-periods from the onset of the electromyogram to 3000 ms before movement and the magnetoencephalogram signals following stimulation in each sub-period were averaged. Multiple source analysis indicated that the equivalent current dipoles (ECDs) were located in SI and bilateral SII. Although the ECD moment for N 20 m (the upward deflection peaking at around 20 ms) was not significantly changed, that for P 30 m (the downward deflection peaking at around 30 m) was significantly smaller in the 0- to -500-ms sub-period than the -2000- to -3000-ms sub-period. As for SII, the ECD moment for the SII ipsilateral to movement showed no significant change, while that for the contralateral SII was significantly larger in the 0- to -500-ms sub-period than the -1500- to -2000-ms or -2000- to -3000-ms sub-period. The opposite effects of movement on SI and SII cortices indicated that these cortical areas play a different role in the function of the sensorimotor integration and are affected differently by the centrifugal process.
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Affiliation(s)
- Toshiaki Wasaka
- Department of Integrative Physiology, National Institute for Physiological Sciences, Okazaki, Japan.
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Arnfred SM. Proprioceptive event related potentials: gating and task effects. Clin Neurophysiol 2005; 116:849-60. [PMID: 15792894 DOI: 10.1016/j.clinph.2004.11.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2004] [Revised: 11/08/2004] [Accepted: 11/09/2004] [Indexed: 11/23/2022]
Abstract
OBJECTIVE The integration of proprioception with vision, touch or audition is considered basic to the developmental formation of perceptions, conceptual objects and the creation of cognitive schemes. Thus, mapping of proprioceptive information processing is important in cognitive research. A stimulus of a brisk change of weight on a hand held load elicit a proprioceptive evoked potential (PEP). Here this is used to examine early and late information processing related to weight discrimination by event related potentials (ERP). METHODS A gating paradigm having 1s between the proprioceptive stimuli of 100 g weight increase was recorded in 12 runs of 40 pairs and an 1:4 oddball task of discriminating between 40 and 100 g weight increase was both recorded in 24 healthy men. The subjects were stratified in 3 groups according to their discrimination errors. RESULTS The proprioceptive event related potential (PERP) consisted of a contralateral parietal P60, frontal N70, midline P100, initial contralateral later widespread N160, vertex P200, parietal N290 and target related widespread P360 and posterior N500. The target related components were augmented in the best performers, while the bad performers had delayed P60 and attenuated N70. The amplitudes of N160, P200 and N290 were unrelated to performance. Gating was seen as attenuation of P100, N160 and P200 amplitude. CONCLUSIONS The proprioceptive stimulus feature processing seem to be accomplished in the first 100 ms, while later components are modified by context as expected from previous findings in the somatosensory modality. SIGNIFICANCE The PERP could be a useful research tool in the investigation of bodily information processing in neuropsychiatric disorders.
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Affiliation(s)
- Sidse M Arnfred
- Department of Psychiatry, Hvidovre Hospital, University Hospital of Copenhagen, Brøndbyøstervej 160, 2605 Brøndby, Copenhagen, Denmark.
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Wasaka T, Hoshiyama M, Nakata H, Nishihira Y, Kakigi R. Gating of somatosensory evoked magnetic fields during the preparatory period of self-initiated finger movement. Neuroimage 2003; 20:1830-8. [PMID: 14642492 DOI: 10.1016/s1053-8119(03)00442-7] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The temporal change in somatosensory evoked magnetic fields (SEFs) in the preparatory period of self-initiated voluntary movement was investigated. The SEF following stimulation of the right median nerve was recorded, using a 204-channel whole-head MEG system, in nine healthy subjects during a self-initiated extension of the right index finger every 5 to 7 s. The preparatory period before finger movement was divided into six subperiods, and the MEG signals following the stimulation in each subperiod were averaged separately. SEFs were also recorded in the resting state. The ECD strengths for N20m and P60m were not significantly changed in any subperiod before movement compared with those in the resting state. The ECD strength for P30m was significantly smaller 500 ms or less before movement than during the resting state and 1,500 ms or less before movement compared to that during the period from 3,000 to 4,000 ms before movement. Thus, we confirmed that the SEF components were attenuated even during a period of self-initiated voluntary movement. The modulation started at least 1,500 ms before movement and was greater for the P30m than the N20m component. These findings suggested that motor-associated cortices attenuated SEF components by a centrifugal gating process.
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Affiliation(s)
- Toshiaki Wasaka
- Department of Integrative Physiology, National Institute for Physiological Sciences, Myodaiji, Okazaki, 444, Japan
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26
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Hamada Y, Otsuka S, Okamoto T, Suzuki R. The profile of the recovery cycle in human primary and secondary somatosensory cortex: a magnetoencephalography study. Clin Neurophysiol 2002; 113:1787-93. [PMID: 12417232 DOI: 10.1016/s1388-2457(02)00258-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE To estimate the lifetime of sensory memory in human primary (SI) and secondary (SII) somatosensory cortex with a view to furthering our understanding of the roles played by these cortices in the processing of tactile information. METHODS Somatosensory evoked fields (SEFs) were recorded following trains of 5 electrical pulses applied to the right median nerve at the wrist using a whole-head 80 channel magnetoencephalography (MEG) system. Recordings were acquired for trains of pulses with differing interstimulus intervals (ISIs) occurring at 100, 200, 300, 400 and 500 ms. The profile of SEF intensities for the different ISIs provided an estimate of the recovery cycle of evoked neuronal activity, and the time constant of the exponential curve fitted to the recovery cycle was calculated to obtain a putative measure of the lifetime of somatic sensory memory in SI and SII. RESULTS The estimated time constants were 0.11+/-0.06 s (mean+/-SD) in SI and 0.82+/-0.34 s in SII. The mean time constant in SII was significantly longer than that in SI (Student's paired t test: P=0.021; analysis of variance: F(1,3)=19.7, P=0.021). CONCLUSIONS These data indicate that the lifetime of somatic sensory memory is of longer duration in higher order cortical areas than in primary sensory cortex in the somatosensory information processing system.
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Affiliation(s)
- Yasukazu Hamada
- Department of Linguistics and Philosophy, Massachusetts Institute of Technology, Cambridge, MA, USA.
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27
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Arnfred SM, Eder DN, Hemmingsen RP, Glenthøj BY, Chen AC. Gating of the vertex somatosensory and auditory evoked potential P50 and the correlation to skin conductance orienting response in healthy men. Psychiatry Res 2001; 101:221-35. [PMID: 11311925 DOI: 10.1016/s0165-1781(01)00226-8] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A defect in auditory evoked potential (AEP) P50 gating supports the theory of information-processing deficits in schizophrenia. The relationship between gating of the mid-latency evoked potentials (EP) in the somatosensory and the auditory modalities has not been studied together before. In schizophrenia, we might expect the processing deficits to act on multiple modalities. We have examined the gating of median nerve somatosensory EP (SEP) following paired stimulation identical to the AEP P50 gating paradigm using interstimulus intervals (ISI) of 500, 750 and 1000 ms and the correlation of gating to the skin conductance orienting response (SCOR) in 20 healthy men. We measured mid-latency vertex components (SEP: P50, N65, P85 and N100; AEP: P30, N45, P50 and N80). The gating was most pronounced at ISI 500 ms where the SEP P50 and N100 gating were 0.59 and 0.37, respectively, as compared to a gating of 0.61 in P30, 0.33 in P50 and 0.45 in N80 in the AEP. Repetition effects in the two modalities were not correlated. AEP P50 gating was correlated to skin conductance level (SCL). The combination of recording repetition effects on the mid-latency EP in two modalities could provide a method for investigating if deficits of information processing in schizophrenia are cross-modal.
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Affiliation(s)
- S M Arnfred
- Department of Psychiatry, University Hospital of Copenhagen, Bispebjerg, Bispebjerg Blake 23, DK-2400, København NV, Denmark.
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28
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Kakigi R, Hoshiyama M, Shimojo M, Naka D, Yamasaki H, Watanabe S, Xiang J, Maeda K, Lam K, Itomi K, Nakamura A. The somatosensory evoked magnetic fields. Prog Neurobiol 2000; 61:495-523. [PMID: 10748321 DOI: 10.1016/s0301-0082(99)00063-5] [Citation(s) in RCA: 164] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Averaged magnetoencephalography (MEG) following somatosensory stimulation, somatosensory evoked magnetic field(s) (SEF), in humans are reviewed. The equivalent current dipole(s) (ECD) of the primary and the following middle-latency components of SEF following electrical stimulation within 80-100 ms are estimated in area 3b of the primary somatosensory cortex (SI), the posterior bank of the central sulcus, in the hemisphere contralateral to the stimulated site. Their sites are generally compatible with the homunculus which was reported by Penfield using direct cortical stimulation during surgery. SEF to passive finger movement is generated in area 3a or 2 of SI, unlike with electrical stimulation. Long-latency components with peaks of approximately 80-120 ms are recorded in the bilateral hemispheres and their ECD are estimated in the secondary somatosensory cortex (SII) in the bilateral hemispheres. We also summarized (1) the gating effects on SEF by interference tactile stimulation or movement applied to the stimulus site, (2) clinical applications of SEF in the fields of neurosurgery and neurology and (3) cortical plasticity (reorganization) of the SI. SEF specific to painful stimulation is also recorded following painful stimulation by CO(2) laser beam. Pain-specific components are recorded over 150 ms after the stimulus and their ECD are estimated in the bilateral SII and the limbic system. We introduced a newly-developed multi (12)-channel gradiometer system with the smallest and highest quality superconducting quantum interference device (micro-SQUID) available to non-invasively detect the magnetic fields of a human peripheral nerve. Clear nerve action fields (NAFs) were consistently recorded from all subjects.
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Affiliation(s)
- R Kakigi
- Department of Integrative Physiology, National Institute for Physiological Sciences, Myodaiji, Okazaki, Japan.
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Valeriani M, Le Pera D, Niddam D, Arendt-Nielsen L, Chen AC. Dipolar source modeling of somatosensory evoked potentials to painful and nonpainful median nerve stimulation. Muscle Nerve 2000; 23:1194-203. [PMID: 10918255 DOI: 10.1002/1097-4598(200008)23:8<1194::aid-mus6>3.0.co;2-e] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Dipolar source modeling might help in clarifying whether somatosensory evoked potentials (SEPs) after electrical stimulation at painful intensity contain any information related to the nociceptive processing. SEPs were recorded after left median nerve stimulation at three different intensities: intense but nonpainful (intensity 2); slightly painful (pain threshold; intensity 4); and moderately painful (intensity 6). Scalp SEPs at intensities 2, 4, and 6 were fitted by a five-dipole model. When the strength modifications of the source activities up to 40 ms were examined across the different stimulus intensities, no significant difference was found. In the later epoch (40-200 ms), a posterior parietal dipole and two bilateral sources probably located in the second somatosensory (SII) areas increased significantly their dipole moments when the stimulus was increased from 2 to 4 and became painful. Since no difference was found when the stimulus intensity was increased from 4 to 6, the observed increase of the dipolar strengths is probably related to a variation of the stimulus quality (nonpainful vs. painful), rather than of the stimulus intensity per se. Our findings lead us to conclude that a large convergence of nociceptive and non-nociceptive afferents probably occurs bilaterally in the SII areas.
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Affiliation(s)
- M Valeriani
- Department of Neurology, Università Cattolica del Sacro Cuore, Rome, Italy.
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Kanda M, Nagamine T, Ikeda A, Ohara S, Kunieda T, Fujiwara N, Yazawa S, Sawamoto N, Matsumoto R, Taki W, Shibasaki H. Primary somatosensory cortex is actively involved in pain processing in human. Brain Res 2000; 853:282-9. [PMID: 10640625 DOI: 10.1016/s0006-8993(99)02274-x] [Citation(s) in RCA: 138] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We recorded somatosensory evoked magnetic fields (SEFs) by a whole head magnetometer to elucidate cortical receptive areas involved in pain processing, focusing on the primary somatosensory cortex (SI), following painful CO(2) laser stimulation of the dorsum of the left hand in 12 healthy human subjects. In seven subjects, three spatially segregated cortical areas (contralateral SI and bilateral second (SII) somatosensory cortices) were simultaneously activated at around 210 ms after the stimulus, suggesting parallel processing of pain information in SI and SII. Equivalent current dipole (ECD) in SI pointed anteriorly in three subjects whereas posteriorly in the remaining four. We also recorded SEFs following electric stimulation of the left median nerve at wrist in three subjects. ECD of CO(2) laser stimulation was located medial-superior to that of electric stimulation in all three subjects. In addition, by direct recording of somatosensory evoked potentials (SEPs) from peri-Rolandic cortex by subdural electrodes in an epilepsy patient, we identified a response to the laser stimulation over the contralateral SI with the peak latency of 220 ms. Its distribution was similar to, but slightly wider than, that of P25 of electric SEPs. Taken together, it is postulated that the pain impulse is received in the crown of the postcentral gyrus in human.
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Affiliation(s)
- M Kanda
- Department of Brain Pathophysiology, Kyoto University Graduate School of Medicine, Kyoto, Japan
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Hari R, Forss N. Magnetoencephalography in the study of human somatosensory cortical processing. Philos Trans R Soc Lond B Biol Sci 1999; 354:1145-54. [PMID: 10466142 PMCID: PMC1692629 DOI: 10.1098/rstb.1999.0470] [Citation(s) in RCA: 249] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Magnetoencephalography (MEG) is a totally non-invasive research method which provides information about cortical dynamics on a millisecond time-scale. Whole-scalp magnetic field patterns following stimulation of different peripheral nerves indicate activation of an extensive cortical network. At the SI cortex, the responses reflect mainly the activity of area 3b, with clearly somatotopical representations of different body parts. The SII cortex is activated bilaterally and it also receives, besides tactile input, nociceptive afference. Somatically evoked MEG signals may also be detected from the posterior parietal cortex, central mesial cortex and the frontal lobe. The serial versus parallel processing in the cortical somatosensory network is still under debate.
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Affiliation(s)
- R Hari
- Brain Research Unit, Helsinki University of Technology, Espoo, Finland.
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Mima T, Nagamine T, Nakamura K, Shibasaki H. Attention modulates both primary and second somatosensory cortical activities in humans: a magnetoencephalographic study. J Neurophysiol 1998; 80:2215-21. [PMID: 9772274 DOI: 10.1152/jn.1998.80.4.2215] [Citation(s) in RCA: 214] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To clarify the role of primary and second somatosensory cortex (SI and SII) in somatosensory discrimination, we recorded somatosensory evoked magnetic fields during a stimulus strength discrimination task. The temporal pattern of cortical activation was analyzed by dipole source model coregistered with magnetic resonance image. Stimulus intensity was represented in SI as early as 20 ms after the stimulus presentation. The later components of SI response (latency 37.7 and 67.9 ms) were enhanced by rarely presented stimuli (stimulus deviancy) during passive and active attention. This supports an early haptic memory mechanism in human primary sensory cortex. Contra- and ipsilateral SII responses followed the SI responses (latency 124.6 and 138.3 ms, respectively) and were enhanced by attention more prominently than the SI responses. Active attention increased SII but not SI activity. These results are consistent with the concept of ventral somatosensory pathway that SI and SII are hierarchically organized for passive and active detection of discrete stimuli.
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Affiliation(s)
- T Mima
- Department of Brain Pathophysiology, Kyoto University School of Medicine, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
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