scholarly journals Frequency shapes the quality of tactile percepts evoked through electrical stimulation of the nerves

2020 ◽  
Author(s):  
Emily L. Graczyk ◽  
Breanne P. Christie ◽  
Qinpu He ◽  
Dustin J. Tyler ◽  
Sliman J. Bensmaia
Keyword(s):  
Electrical Stimulation ◽  
Peripheral Nerve ◽  
Dimensional Space ◽  
Weber Fraction ◽  
Discrimination Performance ◽  
Nerve Fibers ◽  
Spike Timing ◽  
Neural Population ◽  
Stimulation Of

AbstractThe quality of tactile percepts evoked by skin vibrations depends on the frequency of stimulation: as frequency increases, the vibrotactile “pitch” increases. In the present study, we assessed the degree to which the quality of tactile percepts evoked via electrical stimulation of the somatosensory nerves is shaped by the frequency of the pulse train (PF). Participants with chronically-implanted peripheral nerve interfaces rated the quality of electrical pulse trains that varied in both PF and pulse width (PW) along a single continuum and also described the subjective quality of the sensory experience using perceptual descriptors. We found that increases in PF led to systematic increases in perceived frequency independent of PW, up to about 50 Hz, at which point perceived frequency leveled off or decreased. PF discrimination matched its vibrotactile counterpart, yielding a Weber fraction of ∼0.2 at low frequencies, but discrimination performance was abolished above 50 Hz. Finally, we found that PF systematically shaped quality as characterized by verbal descriptors at low but not high frequencies. Furthermore, even when probed in this complex, multi-dimensional space defined by descriptors, PF modulated tactile quality along a single perceptual continuum. In conclusion, we show that quality can be shaped by imposing temporal patterns on a fixed neural population, highlighting the importance of spike timing in the peripheral nerve. However, this temporal patterning can only be resolved up to about 50 Hz when stimulation is applied to populations of tactile nerve fibers.

ATP concentrations and muscle tension increase linearly with muscle contraction

2003 ◽  
Vol 95 (2) ◽  
pp. 577-583 ◽  
Author(s):  
Jianhua Li ◽  
Nicholas C. King ◽  
Lawrence I. Sinoway
Keyword(s):  
Skeletal Muscle ◽  
Electrical Stimulation ◽  
Muscle Contraction ◽  
Motor Nerve ◽  
Muscle Tension ◽  
Nerve Fibers ◽  
Ventral Root ◽  
Ventral Roots ◽  
Root Stimulation ◽  
Stimulation Of

Previous studies have suggested that activation of ATP-sensitive P2X receptors in skeletal muscle play a role in mediating the exercise pressor reflex (Li J and Sinoway LI. Am J Physiol Heart Circ Physiol 283: H2636–H2643, 2002). To determine the role ATP plays in this reflex, it is necessary to examine whether muscle interstitial ATP (ATPi) concentrations rise with muscle contraction. Accordingly, in this study, muscle contraction was evoked by electrical stimulation of the L7 and S1 ventral roots of the spinal cord in 12 decerebrate cats. Muscle ATPi was collected from microdialysis probes inserted in the muscle. ATP concentrations were determined by the HPLC method. Electrical stimulation of the ventral roots at 3 and 5 Hz increased mean arterial pressure by 13 ± 2 and 16 ± 3 mmHg ( P < 0.05), respectively, and it increased ATP concentration in contracting muscle by 150% ( P < 0.05) and 200% ( P < 0.05), respectively. ATP measured in the opposite control limb did not rise with ventral root stimulation. Section of the L7 and S1 dorsal roots did not affect the ATPi seen with 5-Hz ventral root stimulation. Finally, ventral roots stimulation sufficient to drive motor nerve fibers did not increase ATP in previously paralyzed cats. Thus ATPi is not largely released from sympathetic or motor nerves and does not require an intact afferent reflex pathway. We conclude that ATPi is due to the release of ATP from contracting skeletal muscle cells.

Corticofugal Modulation of the Tactile Response Coherence of Projecting Neurons in the Gracilis Nucleus

2007 ◽  
Vol 98 (5) ◽  
pp. 2537-2549 ◽  
Author(s):  
Nazareth P. Castellanos ◽  
Eduardo Malmierca ◽  
Angel Nuñez ◽  
Valeri A. Makarov
Keyword(s):  
Electrical Stimulation ◽  
Tactile Stimulation ◽  
Spectral Power ◽  
Temporal Structure ◽  
Neural Response ◽  
Spike Timing ◽  
Sensory Stimulus ◽  
Functional Coupling ◽  
Tactile Response ◽  
Stimulation Of

Precise and reproducible spike timing is one of the alternatives of the sensory stimulus encoding. We test coherence (repeatability) of the response patterns elicited in projecting gracile neurons by tactile stimulation and its modulation provoked by electrical stimulation of the corticofugal feedback from the somatosensory (SI) cortex. To gain the temporal structure we adopt the wavelet-based approach for quantification of the functional stimulus–neural response coupling. We show that the spontaneous firing patterns (when they exist) are essentially random. Tactile stimulation of the neuron receptive field strongly increases the spectral power in the stimulus and 5- to 15-Hz frequency bands. However, the functional coupling (coherence) between the sensory stimulus and the neural response exhibits ultraslow oscillation (0.07 Hz). During this oscillation the stimulus coherence can temporarily fall below the statistically significant level, i.e., the functional stimulus–response coupling may be temporarily lost for a single neuron. We further demonstrate that electrical stimulation of the SI cortex increases the stimulus coherence for about 60% of cells. We find no significant correlation between the increment of the firing rate and the stimulus coherence, but we show that there is a positive correlation with the amplitude of the peristimulus time histogram. The latter argues that the observed facilitation of the neural response by the corticofugal pathway, at least in part, may be mediated through an appropriate ordering of the stimulus-evoked firing pattern, and the coherence enhancement is more relevant in gracilis nucleus than an increase of the number of spikes elicited by the tactile stimulus.

Relationships between permeable vessels, nerves, and mast cells in rat cutaneous neurogenic inflammation

1990 ◽  
Vol 68 (6) ◽  
pp. 2305-2311 ◽  
Author(s):  
J. N. Baraniuk ◽  
M. L. Kowalski ◽  
M. A. Kaliner
Keyword(s):  
Electrical Stimulation ◽  
Mast Cells ◽  
Neurogenic Inflammation ◽  
Sensory Nerve ◽  
Nerve Fibers ◽  
Sensory Nerves ◽  
Neurokinin A ◽  
Rat Skin ◽  
Protein Extravasation ◽  
Stimulation Of

Electrical stimulation of rat sensory nerves produces cutaneous vasodilation and plasma protein extravasation, a phenomenon termed “neurogenic inflammation”. Rat skin on the dorsum of the paw developed neurogenic inflammation after electrical stimulation of the saphenous nerve. In tissue sections, the extravasation of the supravital dye monastral blue B identified permeable vessels. Mast cells were identified by toluidine blue stain. Permeable vessels were significantly more dense in the superficial 120 microns of the dermis than in the deeper dermis, whereas mast cells were significantly more frequent in the deeper dermis. The relationships between nociceptive sensory nerve fibers, permeable vessels, and mast cells were examined by indirect immunohistochemistry for calcitonin gene-related peptide (CGRP), neurokinin A (NKA), and substance P (SP). CGRP-, NKA-, and SP-containing nerves densely innervated the superficial dermis and appeared to innervate the vessels that became permeable during neurogenic inflammation. In contrast, mast cells were not associated with either permeable vessels or nerve fibers. These data suggest that electrical stimulation of rat sensory nerves produces vascular permeability by inducing the release of neuropeptides that may directly stimulate the superficial vascular bed. Mast cells may not be involved in this stage of cutaneous neurogenic inflammation in rat skin.

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