scholarly journals Disruption Of Proprioceptive Information During Electrical Stimulation Of The Cutaneous Afferents

2021 ◽  
Author(s):  
Natalija Katic ◽  
Josep-Maria Balaguer ◽  
Oleg Gorskii ◽  
Natalia Pavlova ◽  
Dzhina Karal-ogly ◽  
...  
Keyword(s):  
Neural Activity ◽  
Radial Nerve ◽  
Population Analysis ◽  
Clinical Results ◽  
Cutaneous Afferents ◽  
Proprioceptive Information ◽  
Sensory Regulation ◽  
Proprioceptive Afferents ◽  
Afferent Volleys ◽  
Stimulation Of

Restoration of proprioception with neurotechnology is critical to improve effectiveness of robotic neuro-prostheses. Unfortunately, after initial enthusiasm clinical results showed that unlike touch, proprioception could not be reliably induced. Here we show that concurrent activation of multiple sensory modalities may trigger unwanted sensory regulation mechanisms that disrupt proprioception. We recorded intra-spinal neural activity induced by stimulation of proprioceptive afferents from the radial nerve in three monkeys. Then, we superimposed stimulation of the radial nerve cutaneous branch and quantified its impact on spinal neural activity via population analysis. Proprioceptive pulses produced robust neural trajectories in the neural manifold that were disrupted by concurrent stimulation of cutaneous afferents. This disruption correlated with a reduction of afferent volleys and multi-unit activity both in the spinal cord and somatosensory cortex. Our results suggest that limited specificity not only impacts localization of artificial percepts, but also their nature to an extent that was never considered.

scholarly journals Disruption of Proprioceptive Information During Electrical Stimulation of the Cutaneous Afferents

2021 ◽  
Author(s):  
Natalija Katic ◽  
Josep-Maria Balaguer ◽  
Oleg Gorskii ◽  
Natalia Pavlova ◽  
Dzhina Karal-ogly ◽  
...  
Keyword(s):  
Neural Activity ◽  
Radial Nerve ◽  
Population Analysis ◽  
Clinical Results ◽  
Cutaneous Afferents ◽  
Proprioceptive Information ◽  
Sensory Regulation ◽  
Proprioceptive Afferents ◽  
Afferent Volleys ◽  
Stimulation Of

Abstract Restoration of proprioception with neurotechnology is critical to improve effectiveness of robotic neuro-prostheses. Unfortunately, after initial enthusiasm clinical results showed that unlike touch, proprioception could not be reliably induced. Here we show that concurrent activation of multiple sensory modalities may trigger unwanted sensory regulation mechanisms that disrupt proprioception. We recorded intra-spinal neural activity induced by stimulation of proprioceptive afferents from the radial nerve in three monkeys. Then, we superimposed stimulation of the radial nerve cutaneous branch and quantified its impact on spinal neural activity via population analysis. Proprioceptive pulses produced robust neural trajectories in the neural manifold that were disrupted by concurrent stimulation of cutaneous afferents. This disruption correlated with a reduction of afferent volleys and multi-unit activity both in the spinal cord and somatosensory cortex. Our results suggest that limited specificity not only impacts localization of artificial percepts, but also their nature to an extent that was never considered.

Connections between thoraco-coxal proprioceptive afferents and motor neurons in the locust

2000 ◽  
Vol 203 (3) ◽  
pp. 435-445
Author(s):  
M. Wildman
Keyword(s):  
Electrical Stimulation ◽  
Sensory Neurons ◽  
Motor Neurons ◽  
Chordotonal Organ ◽  
Synaptic Connections ◽  
Afferent Neurons ◽  
Postsynaptic Potentials ◽  
The Common ◽  
Proprioceptive Afferents ◽  
Stimulation Of

The position of the coxal segment of the locust hind leg relative to the thorax is monitored by a variety of proprioceptors, including three chordotonal organs and a myochordotonal organ. The sensory neurons of two of these proprioceptors, the posterior joint chordotonal organ (pjCO) and the myochordotonal organ (MCO), have axons in the purely sensory metathoracic nerve 2C (N2C). The connections made by these afferents with metathoracic motor neurons innervating thoraco-coxal and wing muscles were investigated by electrical stimulation of N2C and by matching postsynaptic potentials in motor neurons with afferent spikes in N2C. Stretch applied to the anterior rotator muscle of the coxa (M121), with which the MCO is associated, evoked sensory spikes in N2C. Some of the MCO afferent neurons make direct excitatory chemical synaptic connections with motor neurons innervating the thoraco-coxal muscles M121, M126 and M125. Parallel polysynaptic pathways via unidentified interneurons also exist between MCO afferents and these motor neurons. Connections with the common inhibitor 1 neuron and motor neurons innervating the thoraco-coxal muscles M123/4 and wing muscles M113 and M127 are polysynaptic. Afferents of the pjCO also make polysynaptic connections with motor neurons innervating thoraco-coxal and wing muscles, but no evidence for monosynaptic pathways was found.

The Electrical Activity of the Radial Nerve in Diadema antillarum Philippi and Certain Other Echinoids

1968 ◽  
Vol 48 (2) ◽  
pp. 279-289
Author(s):  
N. MILLOTT ◽  
H. OKUMURA
Keyword(s):  
Electrical Activity ◽  
Conduction Velocity ◽  
Radial Nerve ◽  
Diadema Antillarum ◽  
Double Peak ◽  
Slow Potential ◽  
Refractory Periods ◽  
Spine Movement ◽  
Stimulation Of

1. The propagated massed potentials which follow stimulation of the radial nerve in Arbacia, Diadema, Echinus and Paracentrotus are described. 2. Approximate values for the averaged absolute and relative refractory periods and the conduction velocity were obtained. 3. The response of Diadema has a double peak which is shown to represent responses of nerves differing in excitability and conduction velocity. The fast potential is concerned with spine movement. The slow potential is related to inhibition of spine movements excited photically.

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.

Heptanol But Not Fluoroacetate Prevents the Propagation of Spreading Depression in Rat Hippocampal Slices

1997 ◽  
Vol 77 (1) ◽  
pp. 9-16 ◽  
Author(s):  
Carlota Largo ◽  
Geoffrey C. Tombaugh ◽  
Peter G. Aitken ◽  
Oscar Herreras ◽  
George G. Somjen
Keyword(s):  
Synaptic Transmission ◽  
Gap Junctions ◽  
Spreading Depression ◽  
Pyramidal Neurons ◽  
Hippocampal Slices ◽  
Lipid Phase ◽  
Tissue Slices ◽  
Population Spikes ◽  
Afferent Volleys ◽  
Stimulation Of

Largo, Carlota, Geoffrey C. Tombaugh, Peter G. Aitken, Oscar Herreras, and George G. Somjen. Heptanol but not fluoroacetate prevents the propagation of spreading depression in rat hippocampal slices. J. Neurophysiol. 77: 9–16, 1997. We investigated whether heptanol and other long-chain alcohols that are known to block gap junctions interfere with the generation or the propagation of spreading depression (SD). Waves of SD were triggered by micro-injection of concentrated KCl solution in stratum (s.) radiatum of CA1 of rat hippocampal tissue slices. DC-coupled recordings of extracellular potential ( V o) were made at the injection and at a second site ∼1 mm distant in st. radiatum and sometimes also in st. pyramidale. Extracellular excitatory postsynaptic potentials (fEPSPs) were evoked by stimulation of the Schaffer collateral bundle; in some experiments, antidromic population spikes were evoked by stimulation of the alveus. Bath application of 3 mM heptanol or 5 mM hexanol completely and reversibly prevented the propagation of the SD-related potential shift (Δ V o) without abolishing the Δ V o at the injection site. Octanol (1 mM) had a similar but less reliably reversible effect. fEPSPs were depressed by ∼30% by heptanol and octanol, 65% by hexanol. Antidromic population spikes were depressed by 30%. In isolated, patch-clamped CA1 pyramidal neurons, heptanol partially and reversibly depressed voltage-dependent Na currents possibly explaining the slight depression of antidromic spikes and, by acting on presynaptic action potentials, also the depression of fEPSPs. Fluoroacetate (FAc), a putative selective blocker of glial metabolism, first induced multiple spike firing in response to single afferent volleys and then severely suppressed synaptic transmission (confirming earlier reports) without depressing the antidromic population spike. FAc did not inhibit SD propagation. The effect of alkyl alcohols is compatible with the idea that the opening of normally closed neuronal gap junctions is required for SD propagation. Alternative possible explanations include interference with the lipid phase of neuron membranes. The absence of SD inhibition by FAc confirms that synaptic transmission is not necessary for the propagation of SD, and it suggests that normally functioning glial cells are not essential for SD generation or propagation.

Identification of a subsurface area in the ventral medulla sensitive to local changes in PCO2

1992 ◽  
Vol 72 (2) ◽  
pp. 439-446 ◽  
Author(s):  
F. G. Issa ◽  
J. E. Remmers
Keyword(s):  
Spinal Cord ◽  
Neural Activity ◽  
Ventral Surface ◽  
Sudden Increase ◽  
Neonatal Rats ◽  
Central Chemoreceptors ◽  
Ventral Medulla ◽  
Ventromedial Medulla ◽  
Stimulation Of

The exact location of the central respiratory chemoreceptors sensitive to changes in PCO2 has not yet been determined. To avoid the confounding effects of the cerebral circulation, we used the in vitro brain stem-spinal cord of neonatal rats (1–5 days old) to identify areas within 500 microns of the ventral surface of the medulla where changes in PCO2 evoked a sudden increase in the rate of respiratory neural activity. The preparation was superfused with mock cerebrospinal fluid (CSF) while maintained at constant temperature (26 +/- 1 degrees C) and pH (7.34). Respiratory frequency increased linearly with decreases in superfusate pH (r2 = 0.92, P less than 0.001), indicating that the respiratory circuitry for the detection of CO2 and stimulation of breathing was intact in this preparation. The search for central chemoreceptors was performed with a specially designed micropipette that allowed microejection of 2–10 nl of mock CSF equilibrated with different CO2-O2 gas mixtures. The pipette was advanced in 50- to 100-microns steps by use of a microdrive to a maximum depth of 500 microns from the surface of the ventral medulla. Depending on the location of the micropipette, ejection of CO2-acidified mock CSF at depths of 100–350 microns below the ventral surface of the medulla stimulated neural respiratory output. Using this response as an indication of the location of central respiratory chemoreceptors, we found that chemoreceptive elements were located in a column in the ventromedial medulla extending from the hypoglossal rootlets caudally to an area 0.75 mm caudal to VI nerve in the rostral medulla.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Cutaneous stimulation evokes long-lasting excitation of spinal interneurons in the turtle

1990 ◽  
Vol 64 (4) ◽  
pp. 1134-1148 ◽  
Author(s):  
S. N. Currie ◽  
P. S. Stein
Keyword(s):  
Spinal Cord ◽  
Receptive Field ◽  
Action Potential ◽  
Receptive Fields ◽  
Neural Mechanisms ◽  
Cutaneous Afferents ◽  
Cutaneous Stimulation ◽  
Single Action ◽  
Single Action Potential ◽  
Stimulation Of

1. We demonstrated multisecond increases in the excitability of the rostral-scratch reflex in the turtle by electrically stimulating the shell at sites within the rostral-scratch receptive field. To examine the cellular mechanisms for these multisecond increases in scratch excitability, we recorded from single cutaneous afferents and sensory interneurons that responded to stimulation of the shell within the rostral-scratch receptive field. A single segment of the midbody spinal cord (D4, the 4th postcervical segment) was isolated in situ by transecting the spinal cord at the segment's anterior and posterior borders. The isolated segment was left attached to its peripheral nerve that innervates part of the rostral-scratch receptive field. A microsuction electrode (4-5 microns ID) was used to record extracellularly from the descending axons of cutaneous afferents and interneurons in the spinal white matter at the posterior end of the D4 segment. 2. The turtle shell is innervated by slowly and rapidly adapting cutaneous afferents. All cutaneous afferents responded to a single electrical stimulus to the shell with a single action potential. Maintained mechanical stimulation applied to the receptive field of some slowly adapting afferents produced several seconds of afterdischarge at stimulus offset. We refer to the cutaneous afferent afterdischarge caused by mechanical stimulation of the shell as "peripheral afterdischarge." 3. Within the D4 spinal segment there were some interneurons that responded to a brief mechanical stimulus within their receptive fields on the shell with short afterdischarge and others that responded with long afterdischarge. Short-afterdischarge interneurons responded to a single electrical pulse to a site in their receptive fields either with a brief train of action potentials or with a single action potential. Long-afterdischarge interneurons responded to a single electrical shell stimulus with up to 30 s of afterdischarge. Long-afterdischarge interneurons also exhibited strong temporal summation in response to a pair of electrical shell stimuli delivered up to several seconds apart. Because all cutaneous afferents responded to an electrical shell stimulus with a single action potential, we conclude that electrically evoked afterdischarge in interneurons was produced by neural mechanisms in the spinal cord; we refer to this type of afterdischarge as "central afterdischarge." 4. These results demonstrate that neural mechanisms for long-lasting excitability changes in response to cutaneous stimulation reside in a single segment of the spinal cord. Cutaneous interneurons with long afterdischarge may serve as cellular loci for multise

Effects on Peroneal Motoneurons of Cutaneous Afferents Activated by Mechanical or Electrical Stimulations

2000 ◽  
Vol 83 (6) ◽  
pp. 3209-3216 ◽  
Author(s):  
Jean-François Perrier ◽  
Boris Lamotte D'Incamps ◽  
Nezha Kouchtir-Devanne ◽  
Léna Jami ◽  
Daniel Zytnicki
Keyword(s):  
Electrical Stimulation ◽  
Mechanical Stimulation ◽  
Cutaneous Afferents ◽  
Postsynaptic Potentials ◽  
Electric Pulses ◽  
Plantar Surface ◽  
Cutaneous Reflex ◽  
Inhibitory Postsynaptic Potentials ◽  
Mixed Pattern ◽  
Stimulation Of

The postsynaptic potentials elicited in peroneal motoneurons by either mechanical stimulation of cutaneous areas innervated by the superficial peroneal nerve (SP) or repetitive electrical stimulation of SP were compared in anesthetized cats. After denervation of the foot sparing only the territory of SP terminal branches, reproducible mechanical stimulations were applied by pressure on the plantar surface of the toes via a plastic disk attached to a servo-length device, causing a mild compression of toes. This stimulus evoked small but consistent postsynaptic potentials in every peroneal motoneuron. Weak stimuli elicited only excitatory postsynaptic potentials (EPSPs), whereas increase in stimulation strength allowed distinction of three patterns of response. In about one half of the sample, mechanical stimulation or trains of 20/s electric pulses at strengths up to six times the threshold of the most excitable fibers in the nerve evoked only EPSPs. Responses to electrical stimulation appeared with 3–7 ms central latencies, suggesting oligosynaptic pathways. In another, smaller fraction of the sample, inhibitory postsynaptic potentials (IPSPs) appeared with an increase of stimulation strength, and the last fraction showed a mixed pattern of excitation and inhibition. In 24 of 32 motoneurons where electrical and mechanical effects could be compared, the responses were similar, and in 6 others, they changed from pure excitation on mechanical stimulation to mixed on electrical stimulation. With both kinds of stimulation, stronger stimulations were required to evoke inhibitory postsynaptic potentials (IPSPs), which appeared at longer central latencies than EPSPs, indicating longer interneuronal pathways. The similarity of responses to mechanical and electrical stimulation in a majority of peroneal motoneurons suggests that the effects of commonly used electrical stimulation are good predictors of the responses of peroneal motoneurons to natural skin stimulation. The different types of responses to cutaneous afferents from SP territory reflect a complex connectivity allowing modulations of cutaneous reflex responses in various postures and gaits.

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