Frequency modulation of neuronal theta-bursts in rabbit's septum by low-frequency repetitive stimulation of the afferent pathways

1. The effects of repetitive stimulation of primary afferents in lumbar dorsal roots on synaptic transmission in the dorsal horn (DH) were studied in a rat spinal cord slice-dorsal root ganglion (DRG)-peripheral nerve trunk preparation by the use of intracellular recording from neurons (n = 115) of the spinal dorsal horn (depth 147 +/- 139, mean +/- SD). All DH neurons were excited synaptically by electrical stimulation of the dorsal root or the peripheral nerve trunk. The electrical shocks were calibrated to produce activation either of large fibers (10–20 V, 0.02 ms) or the whole fiber population including unmyelinated afferents (supramaximal stimulus: > 35 V, 0.5 ms). Postsynaptic potentials induced by low intensity repetitive stimulation of primary afferents at frequencies below 5 Hz failed to produce a prolonged change in the resting membrane potential. In 97/115 DH neurons, slow excitatory postsynaptic potentials (EPSP)--evoked by high intensity low-frequency repetitive stimulation (0.1–2 Hz) of primary afferents--summated, producing a prolonged cumulative depolarization. In the remaining 18/115 DH neurons, high intensity low-frequency stimulation produced a cumulative hyperpolarizing response. 2. In 22 of 97 neurons that responded to high intensity repetitive stimulation with a cumulative depolarization, wind-up in the firing of action potentials was recorded. In all but two experiments, neurons that responded with wind-up to stimulation of one root responded with wind-up to stimulation of the adjacent dorsal root. In 14/22 wind-up neurons, the synaptic response to high intensity stimulation of primary afferents was composed of a short latency EPSP, followed by an inhibitory postsynaptic potential (IPSP), followed by a slow EPSP. The decrease of the amplitude and duration of the IPSP obtained during train stimulation did not seem to contribute to facilitation of transmission induced by repetitive stimulation. 3. The wind-up in firing of action potentials was followed by a prolonged potentiation of synaptic transmission in tetanized synapses. A test of other, adjacent primary afferents revealed that these synapses in the neurons in the superficial laminae had not undergone potentiation. This “synaptic specificity” of post-wind-up potentiation suggested that the mechanism for the induction of stimulation-dependent changes in the excitability of the DH neuron is presynaptic to the recorded-from neuron. 4. In a concentration of 0.5 microM and higher, tetrodotoxin (TTX) applied to sensory neurons selectively blocked action potentials in large myelinated primary afferents.(ABSTRACT TRUNCATED AT 400 WORDS)

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Changes in responses of medial pontomedullary reticular neurons during repetitive cutaneous, vestibular, cortical, and tectal stimulation

Journal of Neurophysiology ◽

10.1152/jn.1976.39.3.564 ◽

1976 ◽

Vol 39 (3) ◽

pp. 564-581 ◽

Cited By ~ 47

Author(s):

B. W. Peterson ◽

J. I. Franck ◽

N. G. Daunton

Keyword(s):

Spinal Cord ◽

Superior Colliculus ◽

Body Surface ◽

Repetitive Stimulation ◽

The Body ◽

Response Decrement ◽

Afferent Pathways ◽

Stimulus Rate ◽

Reticular Neurons ◽

Stimulation Of

1. In cats anesthetized with chloralose, responses of medial pontomedullary reticular neurons to stimulation of the body surface, vestibular nerves, superior colliculi, pericruciate cortices, cerebral peduncles, and spinal cord were studied at different stimulus rates. Raising the rate from 1/10 s to between 1/4 s and 2/s caused a significant decrement or increment in the response of most neurons tested. Response decrement typically began near the beginning of the higher frequency stimulus sequence and increased throughout the sequence. Response increment usually began somewhat later, rose to a peak, and then declined. Recovery from response decrement or increment usually occurred within 30-60 s at a 1/10 s stimulus rate.2. Measurements of response latency and of changes occurring in the initial and longer latency portions of responses indicated that all components of a response typically decreased or increased in parallel. Background spontaneous activity did not change during response decrements, but sometimes increased during response increment.3. Where changes could be detected, response decrement usually developed more rapidly when a sequence of repetitive stimulation was repeated.4. Response decrement was most pronounced at the highest stimulation rates and lowest stimulus intensities. Response increment was usually maximal at a stimulus rate of 1/s: at lower rates less increment occurred; at higher rates responses began to exhibit decrement.5. Response changes varied with the type of stimulus applied. Response decrements predominated when the body surface, vestibular nerves, or ipsilateral superior colliculus were stimulated. Approximately equal amounts of response increment and decrement were produced by repetitive stimulation of the cerebral peduncles and contralateral superior colliculus. Stimulation of the surface of the pericruciate cortex or of the spinal cord usually produced a long-lasting response increment.6. Generalization of response decrement and increment was observed in cases where trains of stimuli at a rate of 2/s applied to one point produced changes in the response to stimulation of another point which was tested once per 10 s and where single-shock stimulation of the first point was without effect on the test response. Generalization of response decrement occurred most often when two nearby points were stimulated. Generalization of response increment appeared to spread widely between distant cutaneous points and stimuli of different kinds.7. The response decrement and increment observed in medial pontomedullary reticular neurons displayed most of the parametric features of behavioral habituation and sensitization (8, 33) and therefore appear to represent neural analogs of these latter phenomena. The properties of response decrement suggest that it may occur to a large extent within afferent pathways leading to medial reticular neurons...

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Early Responsiveness of Ocular Symptoms of Myasthenia Gravis with Plasma Exchange

RRNMF Neuromuscular Journal ◽

10.17161/rrnmf.v1i5.14615 ◽

2020 ◽

Vol 1 (5) ◽

pp. 57

Author(s):

Raghav Govindarajan

Keyword(s):

Emergency Department ◽

Myasthenia Gravis ◽

Plasma Exchange ◽

Complete Resolution ◽

Low Frequency ◽

Complete Response ◽

Older Men ◽

Repetitive Stimulation ◽

Ocular Symptoms ◽

Stimulation Of

75-year-old male presente with ptosis (figure 1), fatigue, slurred speech and dysphagia to the emergency department. Low frequency repetitive stimulation of the spinal acessory nerve with recordong from trapeius showed signifivant decrement. Plama excange was started and three days after treatment there was complete resolution of ptosis (figure 2). Older men show complete responsiveness to plasma exchange including an early and near complete response tp ocular symptoms.

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Correlation of respiratory function tests with repetitive stimulation of long thoracic nerve in myasthenia gravis

Neurological Sciences and Neurophysiology ◽

10.24165/jns.10020.17 ◽

2017 ◽

Author(s):

Fatma GenÇ ◽

Aylİn Yaman ◽

Burcu YÜksel ◽

Yasemİn BİÇer GÖmcelİ ◽

GÜlnİhal Kutlu

Keyword(s):

Myasthenia Gravis ◽

Respiratory Function ◽

Respiratory Function Tests ◽

Repetitive Stimulation ◽

Long Thoracic Nerve ◽

Thoracic Nerve ◽

Function Tests ◽

Stimulation Of

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Deep Brain Stimulation of the Posterior Insula in Chronic Pain: A Theoretical Framework

Brain Sciences ◽

10.3390/brainsci11050639 ◽

2021 ◽

Vol 11 (5) ◽

pp. 639

Author(s):

David Bergeron ◽

Sami Obaid ◽

Marie-Pierre Fournier-Gosselin ◽

Alain Bouthillier ◽

Dang Khoa Nguyen

Keyword(s):

Chronic Pain ◽

Electrical Stimulation ◽

Deep Brain Stimulation ◽

Brain Stimulation ◽

High Frequency ◽

Brain Lesion ◽

Low Frequency ◽

Posterior Insula ◽

Deep Brain ◽

Stimulation Of

Introduction: To date, clinical trials of deep brain stimulation (DBS) for refractory chronic pain have yielded unsatisfying results. Recent evidence suggests that the posterior insula may represent a promising DBS target for this indication. Methods: We present a narrative review highlighting the theoretical basis of posterior insula DBS in patients with chronic pain. Results: Neuroanatomical studies identified the posterior insula as an important cortical relay center for pain and interoception. Intracranial neuronal recordings showed that the earliest response to painful laser stimulation occurs in the posterior insula. The posterior insula is one of the only regions in the brain whose low-frequency electrical stimulation can elicit painful sensations. Most chronic pain syndromes, such as fibromyalgia, had abnormal functional connectivity of the posterior insula on functional imaging. Finally, preliminary results indicated that high-frequency electrical stimulation of the posterior insula can acutely increase pain thresholds. Conclusion: In light of the converging evidence from neuroanatomical, brain lesion, neuroimaging, and intracranial recording and stimulation as well as non-invasive stimulation studies, it appears that the insula is a critical hub for central integration and processing of painful stimuli, whose high-frequency electrical stimulation has the potential to relieve patients from the sensory and affective burden of chronic pain.

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Induction of long-term potentiation without participation of N-methyl-D-aspartate receptors in kitten visual cortex

Journal of Neurophysiology ◽

10.1152/jn.1991.65.1.20 ◽

1991 ◽

Vol 65 (1) ◽

pp. 20-32 ◽

Cited By ~ 47

Author(s):

Y. Komatsu ◽

S. Nakajima ◽

K. Toyama

Keyword(s):

Nmda Receptors ◽

Stimulus Frequency ◽

Low Frequency ◽

Nmda Antagonist ◽

Long Term Potentiation ◽

Conditioning Stimulation ◽

Postsynaptic Potential ◽

Term Potentiation ◽

Stimulation Of

1. Intracellular recording was made from layer II-III cells in slice preparations of kitten (30-40 days old) visual cortex. Low-frequency (0.1 Hz) stimulation of white matter (WM) usually evoked an excitatory postsynaptic potential (EPSP) followed by an inhibitory postsynaptic potential (IPSP). The postsynaptic potentials (PSPs) showed strong dependence on stimulus frequency. Early component of EPSP and IPSP evoked by weak stimulation both decreased monotonically at frequencies greater than 0.5-1 Hz. Strong stimulation similarly depressed the early EPSP at higher frequencies (greater than 2 Hz) and replaced the IPSP with a late EPSP, which had a maximum amplitude in the stimulus frequency range of 2-5 Hz. 2. Very weak WM stimulation sometimes evoked EPSPs in isolation from IPSPs. The falling phase of the EPSP revealed voltage dependence characteristic to the responses mediated by N-methyl-D-aspartate (NMDA) receptors and was depressed by application of an NMDA antagonist DL-2-amino-5-phosphonovalerate (APV), whereas the rising phase of the EPSP was insensitive to APV. 3. The early EPSPs followed by IPSPs were insensitive to APV but were replaced with a slow depolarizing potential by application of a non-NMDA antagonist 6,7-dinitro-quinoxaline-2,3-dione (DNQX), indicating that the early EPSP is mediated by non-NMDA receptors. The slow depolarization was mediated by NMDA receptors because it was depressed by membrane hyperpolarization or addition of APV. 4. The late EPSP evoked by higher-frequency stimulation was abolished by APV, indicating that it is mediated by NMDA receptors, which are located either on the recorded cell or on presynaptic cells to the recorded cells. 5. Long-term potentiation (LTP) of EPSPs was examined in cells perfused with solutions containing 1 microM bicuculline methiodide (BIM), a gamma-aminobutyric acid (GABA) antagonist. WM was stimulated at 2 Hz for 15 min as a conditioning stimulus to induce LTP, and the resultant changes were tested by low-frequency (0.1 Hz) stimulation of WM. 6. LTP of early EPSPs occurred in more than one-half of the cells (8/13) after strong conditioning stimulation. The rising slope of the EPSP was increased 1.6 times on average. 7. To test involvement of NMDA receptors in the induction of LTP in the early EPSP, the effect of conditioning stimulation was studied in a solution containing 100 microM APV, which was sufficient to block completely synaptic transmission mediated by NMDA receptors. LTP occurred in the same frequency and magnitude as in control solution.

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Effects of low-frequency stimulation of the superior colliculus on spontaneous and visually guided saccades

Journal of Neurophysiology ◽

10.1152/jn.1993.69.3.953 ◽

1993 ◽

Vol 69 (3) ◽

pp. 953-964 ◽

Cited By ~ 43

Author(s):

P. W. Glimcher ◽

D. L. Sparks

Keyword(s):

Superior Colliculus ◽

Time Course ◽

Low Frequency ◽

Arbitrary Point ◽

Visually Guided ◽

Spontaneous Movements ◽

Low Frequency Stimulation ◽

Frequency Stimulation ◽

Stimulation Current ◽

Stimulation Of

1. The first experiment of this study determined the effects of low-frequency stimulation of the monkey superior colliculus on spontaneous saccades in the dark. Stimulation trains, subthreshold for eliciting short-latency fixed-vector saccades, were highly effective at biasing the metrics (direction and amplitude) of spontaneous movements. During low-frequency stimulation, the distribution of saccade metrics was biased toward the direction and amplitude of movements induced by suprathreshold stimulation of the same collicular location. 2. Low-frequency stimulation biased the distribution of saccade metrics but did not initiate movements. The distribution of intervals between stimulation onset and the onset of the next saccade did not differ significantly from the distribution of intervals between an arbitrary point in time and the onset of the next saccade under unstimulated conditions. 3. Results of our second experiment indicate that low-frequency stimulation also influenced the metrics of visually guided saccades. The magnitude of the stimulation-induced bias increased as stimulation current or frequency was increased. 4. The time course of these effects was analyzed by terminating stimulation immediately before, during, or after visually guided saccades. Stimulation trains terminated at the onset of a movement were as effective as stimulation trains that continued throughout the movement. No effects were observed if stimulation ended 40–60 ms before the movement began. 5. These results show that low-frequency collicular stimulation can influence the direction and amplitude of spontaneous or visually guided saccades without initiating a movement. These data are compatible with the hypothesis that the collicular activity responsible for specifying the horizontal and vertical amplitude of a saccade differs from the type of collicular activity that initiates a saccade.

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Intracellular analysis of trigeminal motoneuron rhythmical activity during stimulation of pontomedullary reticular formation in anesthetized guinea pig

Journal of Neurophysiology ◽

10.1152/jn.1989.62.6.1225 ◽

1989 ◽

Vol 62 (6) ◽

pp. 1225-1236 ◽

Cited By ~ 15

Author(s):

S. M. Gurahian ◽

S. H. Chandler ◽

L. J. Goldberg

Keyword(s):

Reticular Formation ◽

Short Duration ◽

Field Potential ◽

Membrane Potentials ◽

Repetitive Stimulation ◽

Jaw Movements ◽

Postsynaptic Potentials ◽

Duration Stimulus ◽

Long Duration ◽

Stimulation Of

1. The effects of repetitive stimulation of the nucleus pontis caudalis and nucleus gigantocellularis (PnC-Gi) of the reticular formation on jaw opener and closer motoneurons were examined. The PnC-Gi was stimulated at 75 Hz at current intensities less than 90 microA. 2. Rhythmically occurring, long-duration, depolarizing membrane potentials in jaw opener motoneurons [excitatory masticatory drive potential (E-MDP)] and long-duration hyperpolarizing membrane potentials [inhibitory masticatory drive potentials (I-MDP)] in jaw closer motoneurons were evoked by 40-Hz repetitive masticatory cortex stimulation. These potentials were completely suppressed by PnC-Gi stimulation. PnC-Gi stimulation also suppressed the short-duration, stimulus-locked depolarizations [excitatory postsynaptic potentials (EPSPs)] in jaw opener motoneurons and short-duration, stimulus-locked hyperpolarizations [inhibitory postsynaptic potentials (IPSPs)] in jaw closer motoneurons, evoked by the same repetitive cortical stimulation. 3. Short pulse train (3 pulses; 500 Hz) stimulation of the masticatory area of the cortex in the absence of rhythmical jaw movements activated the short-latency paucisynaptic corticotrigeminal pathways and evoked short-duration EPSPs and IPSPs in jaw opener and closer motoneurons, respectively. The same PnC-Gi stimulation that completely suppressed rhythmical MDPs, and stimulus-locked PSPs evoked by repetitive stimulation to the masticatory area of the cortex, produced an average reduction in PSP amplitude of 22 and 17% in jaw closer and opener motoneurons, respectively. 4. PnC-Gi stimulation produced minimal effects on the amplitude of the antidromic digastric field potential or on the intracellularly recorded antidromic digastric action potential. Moreover, PnC-Gi stimulation had little effect on jaw opener or jaw closer motoneuron membrane resting potentials in the absence of rhythmical jaw movements (RJMs). PnC-Gi stimulation produced variable effects on conductance pulses elicited in jaw opener and closer motoneurons in the absence of RJMs. 5. These results indicate that the powerful suppression of cortically evoked MDPs in opener and closer motoneurons during PnC-Gi stimulation is most likely not a result of postsynaptic inhibition of trigeminal motoneurons. It is proposed that this suppression is a result of suppression of activity in neurons responsible for masticatory rhythm generation.

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