Homeostatic Metaplasticity in the Human Somatosensory Cortex

2008 ◽  
Vol 20 (8) ◽  
pp. 1517-1528 ◽  
Author(s):  
Barbara Bliem ◽  
J. Florian M. Müller-Dahlhaus ◽  
Hubert R. Dinse ◽  
Ulf Ziemann
Keyword(s):  
Electrical Stimulation ◽  
Median Nerve ◽  
Somatosensory Cortex ◽  
Discrimination Threshold ◽  
Spatial Discrimination ◽  
High Frequency Stimulation ◽  
Human Motor Cortex ◽  
The Right ◽  
Stimulation Of

Long-term potentiation (LTP) and long-term depression (LTD) are regulated by homeostatic control mechanisms to maintain synaptic strength in a physiological range. Although homeostatic metaplasticity has been demonstrated in the human motor cortex, little is known to which extent it operates in other cortical areas and how it links to behavior. Here we tested homeostatic interactions between two stimulation protocols—paired associative stimulation (PAS) followed by peripheral high-frequency stimulation (pHFS)—on excitability in the human somatosensory cortex and tactile spatial discrimination threshold. PAS employed repeated pairs of electrical stimulation of the right median nerve followed by focal transcranial magnetic stimulation of the left somatosensory cortex at an interstimulus interval of the individual N20 latency minus 15 msec or N20 minus 2.5 msec to induce LTD- or LTP-like plasticity, respectively [Wolters, A., Schmidt, A., Schramm, A., Zeller, D., Naumann, M., Kunesch, E., et al. Timing-dependent plasticity in human primary somatosensory cortex. Journal of Physiology, 565, 1039–1052, 2005]. pHFS always consisted of 20-Hz trains of electrical stimulation of the right median nerve. Excitability in the somatosensory cortex was assessed by median nerve somatosensory evoked cortical potential amplitudes. Tactile spatial discrimination was tested by the grating orientation task. PAS had no significant effect on excitability in the somatosensory cortex or on tactile discrimination. However, the direction of effects induced by subsequent pHFS varied with the preconditioning PAS protocol: After PASN20-15, excitability tended to increase and tactile spatial discrimination threshold decreased. After PASN20-2.5, excitability decreased and discrimination threshold tended to increase. These interactions demonstrate that homeostatic metaplasticity operates in the human somatosensory cortex, controlling both cortical excitability and somatosensory skill.

Functional magnetic resonance imaging of somatosensory cortex activity produced by electrical stimulation of the median nerve or tactile stimulation of the index finger

2000 ◽  
Vol 93 (5) ◽  
pp. 774-783 ◽  
Author(s):  
Maxwell Boakye ◽  
Sean C. Huckins ◽  
Nikolaus M. Szeverenyi ◽  
Bobby I. Taskey ◽  
Charles J. Hodge
Keyword(s):  
Electrical Stimulation ◽  
Median Nerve ◽  
Somatosensory Cortex ◽  
Tactile Stimulation ◽  
Index Finger ◽  
Functional Magnetic Resonance ◽  
Content Type ◽  
The Right ◽  
Fine Print ◽  
Stimulation Of

Object. Functional magnetic resonance (fMR) imaging was used to determine patterns of cerebral blood flow changes in the somatosensory cortex that result from median nerve stimulation (MNS).Methods. Ten healthy volunteers underwent stimulation of the right median nerve at frequencies of 5.1 Hz (five volunteers) and 50 Hz (five volunteers). The left median nerve was stimulated at frequencies of 5.1 Hz (two volunteers) and 50 Hz (five volunteers). Tactile stimulation (with a soft brush) of the right index finger was also applied (three volunteers). Functional MR imaging data were transformed into Talairach space coordinates and averaged by group. Results showed significant activation (p < 0.001) in the following regions: primary sensorimotor cortex (SMI), secondary somatosensory cortex (SII), parietal operculum, insula, frontal cortex, supplementary motor area, and posterior parietal cortices (Brodmann's Areas 7 and 40). Further analysis revealed no statistically significant difference (p > 0.05) between volumes of cortical activation in the SMI or SII resulting from electrical stimuli at 5.1 Hz and 50 Hz. There existed no significant differences (p > 0.05) in cortical activity in either the SMI or SII resulting from either left- or right-sided MNS. With the exception of the frontal cortex, areas of cortical activity in response to tactile stimulation were anatomically identical to those regions activated by electrical stimulation. In the SMI and SII, activation resulting from tactile stimulation was not significantly different (p > 0.05) from that resulting from electrical stimulation.Conclusions. Electrical stimulation of the median nerve is a reproducible and effective means of activating multiple somatosensory cortical areas, and fMR imaging can be used to investigate the complex network that exists between these areas.

scholarly journals Direct MRI mapping of neuronal activity evoked by electrical stimulation of the median nerve at the right wrist

2009 ◽  
Vol 61 (5) ◽  
pp. 1073-1082 ◽  
Author(s):  
Yiqun Xue ◽  
Xiying Chen ◽  
Thomas Grabowski ◽  
Jinhu Xiong
Keyword(s):  
Electrical Stimulation ◽  
Median Nerve ◽  
Neuronal Activity ◽  
The Right ◽  
Stimulation Of

Electrical stimulation of referred sensation area alleviates phantom limb pain

2021 ◽  
pp. 1-10
Author(s):  
Michihiro Osumi ◽  
Daisuke Shimizu ◽  
Yuki Nishi ◽  
Shu Morioka
Keyword(s):  
Electrical Stimulation ◽  
Single Case ◽  
Phantom Limb Pain ◽  
Phantom Limb ◽  
Long Term Effects ◽  
Limb Pain ◽  
Short Term ◽  
Analgesic Effects ◽  
Stimulation Of

Background: Patients with brachial plexus avulsion (BPA) usually experience phantom sensations and phantom limb pain (PLP) in the deafferented limb. It has been suggested that evoking the sensation of touch in the deafferented limb by stimulating referred sensation areas (RSAs) on the cheek or shoulder might alleviate PLP. However, feasible rehabilitation techniques using this approach have not been reported. Objective: The present study sought to examine the analgesic effects of simple electrical stimulation of RSAs in BPA patients with PLP. Methods: Study 1: Electrical stimulation of RSAs for 60 minutes was conducted for six BPA patients suffering from PLP to examine short-term analgesic effects. Study 2: A single case design experiment was conducted with two BPA patients to investigate whether electrical stimulation of RSAs was more effective for alleviating PLP than control electrical stimulation (electrical stimulation of sites on side opposite to the RSAs), and to elucidate the long-term effects of electrical stimulation of RSAs. Results: Study 1: Electrical stimulation of RSAs evoked phantom touch sensations in the deafferented limb, and significantly alleviated PLP (p <  0.05). Study 2: PLP was alleviated more after electrical stimulation on RSAs compared with control electrical stimulation (p <  0.05). However, the analgesic effects of electrical stimulation on RSAs were observed only in the short term, not in the long term (p >  0.05). Conclusions: Electrical stimulation of RSAs not only evoked phantom touch sensation but also alleviated PLP in the short term. The results indicate that electrical stimulation of RSAs may provide a useful practical rehabilitation technique for PLP. Future studies will be required to clarify the mechanisms underlying immediate PLP alleviation via electrical stimulation of RSAs.

scholarly journals Normalization in human somatosensory cortex

2015 ◽  
Vol 114 (5) ◽  
pp. 2588-2599 ◽  
Author(s):  
Gijs Joost Brouwer ◽  
Vanessa Arnedo ◽  
Shani Offen ◽  
David J. Heeger ◽  
Arthur C. Grant
Keyword(s):  
Somatosensory Cortex ◽  
Middle Finger ◽  
Functional Magnetic Resonance ◽  
Stimulus Amplitude ◽  
Target Digit ◽  
Divisive Normalization ◽  
Postcentral Gyrus ◽  
Baseline Response ◽  
The Right ◽  
Stimulation Of

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.

Activation of thalamic ventroposteriolateral neurons by phrenic nerve afferents in cats and rats

2003 ◽  
Vol 94 (1) ◽  
pp. 220-226 ◽  
Author(s):  
Weirong Zhang ◽  
Paul W. Davenport
Keyword(s):  
Electrical Stimulation ◽  
Somatosensory Cortex ◽  
Phrenic Nerve ◽  
Proprioceptive Information ◽  
Neural Responses ◽  
Afferent Stimulation ◽  
Physiological Conditions ◽  
Sensory Pathways ◽  
Increased Activity ◽  
Stimulation Of

It has been demonstrated that phrenic nerve afferents project to somatosensory cortex, yet the sensory pathways are still poorly understood. This study investigated the neural responses in the thalamic ventroposteriolateral (VPL) nucleus after phrenic afferent stimulation in cats and rats. Activation of VPL neurons was observed after electrical stimulation of the contralateral phrenic nerve. Direct mechanical stimulation of the diaphragm also elicited increased activity in the same VPL neurons that were activated by electrical stimulation of the phrenic nerve. Some VPL neurons responded to both phrenic afferent stimulation and shoulder probing. In rats, VPL neurons activated by inspiratory occlusion also responded to stimulation on phrenic afferents. These results demonstrate that phrenic afferents can reach the VPL thalamus under physiological conditions and support the hypothesis that the thalamic VPL nucleus functions as a relay for the conduction of proprioceptive information from the diaphragm to the contralateral somatosensory cortex.

Human cortical potentials evoked by stimulation of the median nerve. II. Cytoarchitectonic areas generating long-latency activity

1989 ◽  
Vol 62 (3) ◽  
pp. 711-722 ◽  
Author(s):  
T. Allison ◽  
G. McCarthy ◽  
C. C. Wood ◽  
P. D. Williamson ◽  
D. D. Spencer
Keyword(s):  
Spatial Distribution ◽  
Median Nerve ◽  
Somatosensory Cortex ◽  
Sensorimotor Cortex ◽  
Preceding Paper ◽  
Short Latency ◽  
Cortical Surface ◽  
Long Latency ◽  
Area 3B ◽  
Stimulation Of

1. The anatomic generators of human median nerve somatosensory evoked potentials (SEPs) in the 40 to 250-ms latency range were investigated in 54 patients by means of cortical-surface and transcortical recordings obtained during neurosurgery. 2. Contralateral stimulation evoked three groups of SEPs recorded from the hand representation area of sensorimotor cortex: P45-N80-P180, recorded anterior to the central sulcus (CS) and maximal on the precentral gyrus; N45-P80-N180, recorded posterior to the CS and maximal on the postcentral gyrus; and P50-N90-P190, recorded near and on either side of the CS. 3. P45-N80-P180 inverted in polarity to N45-P80-N180 across the CS but was similar in polarity from the cortical surface and white matter in transcortical recordings. These spatial distributions were similar to those of the short-latency P20-N30 and N20-P30 potentials described in the preceding paper, suggesting that these long-latency potentials are generated in area 3b of somatosensory cortex. 4. P50-N90-P190 was largest over the anterior one-half of somatosensory cortex and did not show polarity inversion across the CS. This spatial distribution was similar to that of the short-latency P25-N35 potentials described in the preceding paper and, together with our and Goldring et al. 1970; Stohr and Goldring 1969 transcortical recordings, suggest that these long-latency potentials are generated in area 1 of somatosensory cortex. 5. SEPs of apparently local origin were recorded from several regions of sensorimotor cortex to stimulation of the ipsilateral median nerve. Surface and transcortical recordings suggest that the ipsilateral potentials are generated not in area 3b, but rather in other regions of sensorimotor cortex perhaps including areas 4, 1, 2, and 7. This spatial distribution suggests that the ipsilateral potentials are generated by transcallosal input from the contralateral hemisphere. 6. Recordings from the periSylvian region were characterized by P100 and N100, recorded above and below the Sylvian sulcus (SS) respectively. This distribution suggests a tangential generator located in the upper wall of the SS in the second somatosensory area (SII). In addition, N125 and P200, recorded near and on either side of the SS, suggest a radial generator in a portion of SII located in surface cortex above the SS. 7. In comparison with the short-latency SEPs described in the preceding paper, the long-latency potentials were more variable and were more affected by intraoperative conditions.

Fastigial nucleus-mediated respiratory responses depend on the medullary gigantocellular nucleus

2001 ◽  
Vol 91 (4) ◽  
pp. 1713-1722 ◽  
Author(s):  
Fadi Xu ◽  
Tongrong Zhou ◽  
Tonya Gibson ◽  
Donald T. Frazier
Keyword(s):  
Electrical Stimulation ◽  
Ibotenic Acid ◽  
Major Effect ◽  
Fastigial Nucleus ◽  
Respiratory Response ◽  
The Right ◽  
Spontaneously Breathing ◽  
Respiratory Responses ◽  
Gigantocellular Nucleus ◽  
Stimulation Of

Electrical stimulation of the rostral fastigial nucleus (FNr) alters respiration via activation of local neurons. We hypothesized that this FNr-mediated respiratory response was dependent on the integrity of the nucleus gigantocellularis of the medulla (NGC). Electrical stimulation of the FNr in 15 anesthetized and tracheotomized spontaneously breathing rats significantly altered ventilation by 35.2 ± 11.0% ( P < 0.01) with the major effect being excitatory (78%). This respiratory response did not significantly differ from control after lesions of the NGC via bilateral microinjection of kainic or ibotenic acid (4.5 ± 1.9%; P > 0.05) but persisted in sham controls. Eight other rats, in which horseradish peroxidase (HRP) solution was previously microinjected into the left NGC, served as nonstimulation controls or were exposed to either 15-min repeated electrical stimulation of the right FNr or hypercapnia for 90 min. Histochemical and immunocytochemical data showed that the right FNr contained clustered HRP-labeled neurons, most of which were double labeled with c-Fos immunoreactivity in both electrically and CO2-stimulated rats. We conclude that the NGC receives monosynaptic FNr inputs and is required for fully expressing FNr-mediated respiratory responses.

scholarly journals Properties and Interconnections of Trigeminal Interneurons of the Lateral Pontine Reticular Formation in the Rat

2001 ◽  
Vol 86 (5) ◽  
pp. 2583-2596 ◽  
Author(s):  
M.-J. Bourque ◽  
A. Kolta
Keyword(s):  
Electrical Stimulation ◽  
Reticular Formation ◽  
Motor Pattern ◽  
High Frequency Stimulation ◽  
Motor Nucleus ◽  
Trigeminal Motor Nucleus ◽  
Postsynaptic Potentials ◽  
Frequency Stimulation ◽  
Stimulation Of

Numerous evidence suggests that interneurons located in the lateral tegmentum at the level of the trigeminal motor nucleus contribute importantly to the circuitry involved in mastication. However, the question of whether these neurons participate actively to genesis of the rhythmic motor pattern or simply relay it to trigeminal motoneurons remains open. To answer this question, intracellular recordings were performed in an in vitro slice preparation comprising interneurons of the peritrigeminal area (PeriV) surrounding the trigeminal motor nucleus (NVmt) and the parvocellular reticular formation ventral and caudal to it (PCRt). Intracellular and extracellular injections of anterograde tracers were also used to examine the local connections established by these neurons. In 97% of recordings, electrical stimulation of adjacent areas evoked a postsynaptic potential (PSP). These PSPs were primarily excitatory, but inhibitory and biphasic responses were also induced. Most occurred at latencies longer than those required for monosynaptic transmission and were considered to involve oligosynaptic pathways. Both the anatomical and physiological findings show that all divisions of PeriV and PCRt are extensively interconnected. Most responses followed high-frequency stimulation (50 Hz) and showed little variability in latency indicating that the network reliably distributes inputs across all areas. In all neurons but one, excitatory postsynaptic potentials (EPSPs) or inhibitory postsynaptic potentials (IPSPs) were also elicited by stimulation of NVmt, suggesting the existence of excitatory and inhibitory interneurons within the motor nucleus. In a number of cases, these PSPs were reproduced by local injection of glutamate in lieu of the electrical stimulation. All EPSPs induced by stimulation of PeriV, PCRt, or NVmt were sensitive to ionotropic glutamate receptor antagonists 6-cyano-7-dinitroquinoxaline and d,l-2-amino-5-phosphonovaleric acid, while IPSPs were blocked by bicuculline and strychnine, antagonists of GABAA and glycine receptors. Examination of PeriV and PCRt intrinsic properties indicate that they form a fairly uniform network. Three types of neurons were identified on the basis of their firing adaptation properties. These types were not associated with particular regions. Only 5% of all neurons showed bursting behavior. Our results do not support the hypothesis that neurons of PeriV and PCRt participate actively to rhythm generation, but suggest instead that they are driven by rhythmical synaptic inputs. The organization of the network allows for rapid distribution of this rhythmic input across premotoneuron groups.

scholarly journals Sensory and motor electrophysiological mapping of the cerebellum in humans

2020 ◽  
Author(s):  
Reiko Ashida ◽  
Peter Walsh ◽  
Jonathan C.W. Brooks ◽  
Richard J. Edwards ◽  
Nadia L. Cerminara ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Evoked Potentials ◽  
Posterior Fossa ◽  
Posterior Lobe ◽  
Posterior Fossa Surgery ◽  
Motor Mapping ◽  
Human Cerebellum ◽  
Limb Muscles ◽  
The Right ◽  
Stimulation Of

AbstractDamage to the cerebellum during posterior fossa surgery can lead to ataxia and in paediatric cases, the risk of cerebellar mutism syndrome. Animal electrophysiological and human imaging studies have shown compartmentalisation of sensorimotor and cognitive functions within the cerebellum. In the present study, electrophysiological monitoring of sensory and motor pathways was carried out to assess the location of limb sensorimotor representation within the human cerebellum, as a potential approach for real time assessment of neurophysiological integrity to reduce the incidence of cerebellar surgical morbidities.Thirteen adult and paediatric patients undergoing posterior fossa surgery were recruited. For sensory mapping (n=8), electrical stimulation was applied to the median nerves, the posterior tibial nerves, or proximal and distal limb muscles and evoked field potential responses were sought on the cerebellar surface. For motor mapping (n=5), electrical stimulation was applied to the surface of the cerebellum and evoked EMG responses were sought in facial and limb muscles.Evoked potentials on the cerebellar surface were found in two patients (25% of cases). In one patient, the evoked response was located on the surface of the right inferior posterior cerebellum in response to stimulation of the right leg. In the second patient, stimulation of the extensor digitorum muscle in the left forearm evoked a response on the surface of the left inferior posterior lobe. In the motor mapping cases no evoked EMG responses could be found.Intraoperative electrophysiological mapping, therefore, indicates it is possible to record evoked potentials on the surface of the human cerebellum in response to peripheral stimulation.

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