scholarly journals Lateral inhibition in the somatosensory cortex during and between migraine without aura attacks: Correlations with thalamocortical activity and clinical features

Cephalalgia ◽  
2015 ◽  
Vol 36 (6) ◽  
pp. 568-578 ◽  
Author(s):  
Gianluca Coppola ◽  
Martina Bracaglia ◽  
Davide Di Lenola ◽  
Elisa Iacovelli ◽  
Cherubino Di Lorenzo ◽  
...  
Keyword(s):  
Somatosensory Cortex ◽  
Clinical Features ◽  
Lateral Inhibition ◽  
High Frequency ◽  
Migraine Without Aura ◽  
High Frequency Oscillations ◽  
Cortical Excitation ◽  
Cycle Dependent ◽  
The Right ◽  
Stimulation Of

Background We studied lateral inhibition in the somatosensory cortex of migraineurs during and between attacks, and searched for correlations with thalamocortical activity and clinical features. Participants and methods Somatosensory evoked potentials (SSEP) were obtained by electrical stimulation of the right median (M) or ulnar (U) nerves at the wrist or by simultaneous stimulation of both nerves (MU) in 41 migraine without aura patients, 24 between (MO), 17 during attacks, and in 17 healthy volunteers (HVs). We determined the percentage of lateral inhibition of the N20–P25 component by using the formula [(100)–MU/(M + U)*100]. We also studied high-frequency oscillations (HFOs) reflecting thalamocortical activation. Results In migraine, both lateral inhibition (MO 27.9% vs HVs 40.2%; p = 0.009) and thalamocortical activity (MO 0.5 vs HVs 0.7; p = 0.02) were reduced between attacks, but not during. In MO patients, the percentage of lateral inhibition negatively correlated with days elapsed since the last migraine attack ( r = −0.510, p = 0.01), monthly attack duration ( r = −0.469, p = 0.02) and severity ( r = −0.443, p = 0.03), but positively with thalamocortical activity ( r = −0.463, p = 0.02). Conclusions We hypothesize that abnormal migraine cycle-dependent dynamics of connectivity between subcortical and cortical excitation/inhibition networks may contribute to clinical features of MO and recurrence of attacks.

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.

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.

Generation of high-frequency oscillations in local circuits of rat somatosensory cortex cultures

1996 ◽  
Vol 76 (6) ◽  
pp. 4180-4184 ◽  
Author(s):  
D. Plenz ◽  
S. T. Kitai
Keyword(s):  
High Frequency ◽  
Pyramidal Neurons ◽  
Reversal Potential ◽  
High Frequency Oscillation ◽  
Cortical Circuits ◽  
High Frequency Oscillations ◽  
Rat Somatosensory Cortex ◽  
Local Circuits ◽  
Stimulation Of

1. Rhythmic cortical activity was investigated with intracellular recordings in cortex-striatum-mesencephalon organotypic cultures grown for 42 +/- 3 (SE) days in vitro. 2. Electrical stimulation of supragranular layers induced a self-sustained high-frequency oscillation (HFO) in pyramidal neurons and interneurons. 3. The HFO started 197 +/- 39 ms after stimulation and had a mean duration of 1.0 +/- 0.2 s and an initial frequency of 38 +/- 2 Hz. A decrease in frequency at a rate of 11.5 +/- 2.7 Hz/s started on average 547 +/- 109 ms after the onset of the HFO. 4. During the HFO, local interneurons and pyramidal neurons synchronized their activities. The synaptic origin of the HFO was confirmed by its reversal potential at -57 +/- 4 mV. 5. These results suggest that a self-maintained HFO can be induced in local cortical circuits by excitation of supragranular layers. This HFO would facilitate synchronization between distant cortical and thalamic regions.

Objective high-frequency tinnitus of middle-ear myoclonus

2004 ◽  
Vol 118 (3) ◽  
pp. 231-233 ◽  
Author(s):  
Khader J. Abdul-Baqi
Keyword(s):  
Middle Ear ◽  
High Frequency ◽  
Rare Case ◽  
Rare Condition ◽  
Rhythmic Movements ◽  
Direct Stimulation ◽  
Objective Tinnitus ◽  
The Right ◽  
Otoscopic Examination ◽  
Stimulation Of

Tinnitus produced by middle-ear myoclonus is a rare condition. In this article, a rare case of unilateral continuous high-frequency objective tinnitus caused by middle-ear myoclonus is described. This condition appears to be the second case reported in the literature. Otoscopic examination revealed visible rhythmic movements of the tympanic membrane. Weak clicking sounds were heard around the right ear by auscultation. Direct stimulation of the soft palate showed no evidence of palated myoclonus. Tympanometry confirmed rhythmic changes in the middle-ear compliance. The condition was effectively treated with a muscle relaxant (orphenadrine citrate).

Disinhibition of the somatosensory cortex in cervical dystonia—decreased amplitudes of high-frequency oscillations

2004 ◽  
Vol 115 (7) ◽  
pp. 1624-1630 ◽  
Author(s):  
Ken Inoue ◽  
Isao Hashimoto ◽  
Takushi Shirai ◽  
Hideshi Kawakami ◽  
Takafumi Miyachi ◽  
...  
Keyword(s):  
Somatosensory Cortex ◽  
Cervical Dystonia ◽  
High Frequency ◽  
High Frequency Oscillations

O45: Lateral inhibition in somatosensory cortex of migraine without aura patients between attacks

2014 ◽  
Vol 125 ◽  
pp. S42
Author(s):  
G. Coppola ◽  
M. Bracaglia ◽  
E. Iacovelli ◽  
V. La Salvia ◽  
D. Di Lenola ◽  
...  
Keyword(s):  
Somatosensory Cortex ◽  
Lateral Inhibition ◽  
Migraine Without Aura

scholarly journals P.029 Limbic system involvement in absence seizures

2017 ◽  
Vol 44 (S2) ◽  
pp. S21-S21
Author(s):  
R Ajaz ◽  
SM Mirsattari ◽  
R Mousavi ◽  
S Leung
Keyword(s):  
Limbic System ◽  
Neural Activity ◽  
High Frequency ◽  
Phase Modulation ◽  
Absence Epilepsy ◽  
Field Potentials ◽  
High Frequency Oscillations ◽  
Ventrolateral Thalamus ◽  
Long Evans ◽  
The Right

Background: Absence epilepsy (AE) is believed to be generated by a thalamocortical network. Our laboratory showed that hippocampal neuronal firings were synchronous with the SWDs in the gamma butyrolactone (GBL) model of AE in rats. Here, we hypothesize that high frequency oscillations (HFOs) in the hippocampus and other parts of the limbic system were phase modulated by SWDs Methods: GBL (200 mg/kg i.p) was injected to induce SWDs in 6 male Long-Evans rats. Spontaneous local field potentials (LFPs) were recorded from electrodes implanted in the hippocampus and ventrolateral thalamus bilaterally and the right frontal cortex. For each LFP, modulation index (MI) gives the cross-frequency amplitude modulation of the HFOs (;90-250 Hz) by the phase of the SWD frequency at 2-8 Hz Results: Phase modulation of the HFOs by 2-8 Hz frequency increased for >45 min after GBL injection. MI increase was higher for hippocampal than thalamic LFPs, and not significant for frontal cortical LFP. MI for the nucleus accumbens LFP (N= 1 rat) also increased after GBL Conclusions: The modulation of HFOs (presumed local neural activity) by SWD frequency provides further support that the hippocampus and connected limbic system may become synchronous with the SWDs in AE

Synchronized Spikes of Thalamocortical Axonal Terminals and Cortical Neurons Are Detectable Outside the Pig Brain With MEG

2002 ◽  
Vol 87 (1) ◽  
pp. 626-630 ◽  
Author(s):  
Hiroaki Ikeda ◽  
Leonard Leyba ◽  
Anton Bartolo ◽  
Yaozhi Wang ◽  
Yoshio C. Okada
Keyword(s):  
Electrical Stimulation ◽  
High Frequency ◽  
Cortical Neurons ◽  
Kynurenic Acid ◽  
Cortical Layer ◽  
Projection Area ◽  
High Frequency Oscillations ◽  
Highly Correlated ◽  
The Brain ◽  
Stimulation Of

We show that it is feasible to monitor the synchronized population spikes of the thalamocortical axonal terminals and cortical neurons outside the brain using high-resolution magnetoencephalography (MEG). Electrical stimulation of the snout elicited somatic-evoked magnetic fields (SEFs) above the primary somatosensory cortex (SI) of the piglet. The SEFs contained high-frequency oscillations (HFOs) around 600 Hz similar in many respects to the noninvasively measured HFOs from humans with MEG and electroencephalography (EEG). These HFOs were highly correlated with those in simultaneously measured intracortical somatic-evoked potentials (SEPs) in the snout projection area in SI. Both HFOs in SEFs and SEPs consisted of an initial component insensitive to cortically injected kynurenic acid (Kyna, 20 mM), a nonspecific antagonist of glutamatergic receptors, and a subsequent Kyna-sensitive component. The former was localized in cortical layer IV, indicating that it was due to spikes produced by the specific thalamocortical axonal terminals, whereas the latter was initially localized in layer IV and subsequently in the superficial and deeper layers. These results suggest that it may be possible to study properties of the thalamocortical and cortical spike activities in humans with MEG.

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