Sensory experiences in man evoked by intraneural electrical stimulation of intact cutaneous afferent fibers

1981 ◽  
Vol 42 (2) ◽  
Author(s):  
F. Konietzny ◽  
E.R. Perl ◽  
D. Trevino ◽  
A. Light ◽  
H. Hensel
Keyword(s):  
Electrical Stimulation ◽  
Sensory Experiences ◽  
Afferent Fibers ◽  
Cutaneous Afferent Fibers ◽  
Stimulation Of

Brain stem responses to electrical stimulation of ventral vagal gastric fibers

1989 ◽  
Vol 257 (1) ◽  
pp. G24-G29
Author(s):  
W. D. Barber ◽  
C. S. Yuan
Keyword(s):  
Electrical Stimulation ◽  
Brain Stem ◽  
Time Of Arrival ◽  
Neuronal Responses ◽  
Proximal Stomach ◽  
Afferent Fibers ◽  
Sensory Modalities ◽  
The Mean ◽  
The Brain ◽  
Stimulation Of

The brain stem neuronal responses to electrical stimulation of gastric branches of the ventral vagal trunk serving the proximal stomach were localized and evaluated in anesthetized cats. The responses were equally distributed bilaterally in the region of nucleus solitarius in the caudal brain stem. The mean latency of the response was 289 +/- 46 (SD) ms, which translated into a conduction velocity of less than 1 m/s based on the distance between the stimulating and recording electrodes. The responses consisted of single and multiple spikes that showed slight variability in the latency, indicating orthodromic activation via a synapse in approximately 98% of the responses recorded. Forty two percent of the units tested showed evidence of convergence of input from vagal afferent fibers in different branches of the ventral vagal trunk that served the proximal stomach. The resultant activity pattern of the unitary response appeared to be the product of 1) the gastric sensory input or modality conveyed by the afferent source and 2) the time of arrival and diversity of modalities served by other gastric afferents impinging on the unit. This provides a mechanism capable of responding on the basis of specific sensory modalities that dynamically reflect ongoing events monitored and conveyed by other gastric afferents in the region.

Reflex vasodilatation in the cat lip elicited by stimulation of nasal mucosa by chemical irritants

1993 ◽  
Vol 265 (4) ◽  
pp. R733-R738 ◽  
Author(s):  
H. Izumi ◽  
K. Karita
Keyword(s):  
Blood Flow ◽  
Electrical Stimulation ◽  
Nasal Mucosa ◽  
Threshold Dose ◽  
Ammonia Vapor ◽  
Autonomic Ganglion ◽  
Afferent Fibers ◽  
Autonomic Reflex ◽  
Chemical Irritants ◽  
Stimulation Of

Local application of capsaicin (threshold dose 150 microM) or nicotine (threshold dose 15 mM) to the nasal mucosa as well as electrical stimulation (threshold intensity 10 V) of the nasal mucosa elicited dose- or intensity-dependent blood flow increases in the ipsilateral lower lips of the anesthetized cats. Pretreatment with 3 mM capsaicin applied locally to the nasal mucosa abolished or reduced the vasodilation in response to capsaicin, nicotine, and ammonia vapor but not to light mechanical or electrical stimulation of the nasal mucosa. The blood flow increases elicited by all above stimuli were greatly reduced by pretreatment with hexamethonium, an autonomic ganglion blocker. These results suggest that stimulation of the nasal mucosa by chemical (capsaicin, nicotine, ammonia), mechanical, or electrical methods elicits the autonomic reflex vasodilatation in the cat lower lips. Furthermore, there seem to be at least two types of afferent fibers in the nasal mucosa of the cats: one type is capsaicin-sensitive fibers, while another type is capsaicin-resistant fibers involved in reflex vasodilatation.

Cerebral-evoked potential responses following direct vagal and esophageal electrical stimulation in humans

1993 ◽  
Vol 264 (3) ◽  
pp. G486-G491 ◽  
Author(s):  
G. Tougas ◽  
P. Hudoba ◽  
D. Fitzpatrick ◽  
R. H. Hunt ◽  
A. R. Upton
Keyword(s):  
Electrical Stimulation ◽  
Evoked Potential ◽  
Vagal Stimulation ◽  
Direct Electrical Stimulation ◽  
Sensory Pathways ◽  
Afferent Fibers ◽  
Health And Disease ◽  
Esophageal Sphincter ◽  
Afferent Response ◽  
Stimulation Of

Cerebral evoked responses following direct electrical stimulation of the vagus and esophagus were compared in 8 epileptic subjects and with those recorded after esophageal stimulation in 12 healthy nonepileptic controls. Direct vagal stimulation was performed using a left cervical vagal pacemaker, which is used in the treatment of epilepsy. Esophageal stimulation was obtained with the use of an esophageal assembly incorporating two electrodes positioned 5 and 20 cm orad to the lower esophageal sphincter. Evoked potential responses were recorded with the use of 20 scalp electrodes. The evoked potential responses consisted of three distinct negative peaks and were similar with the use of either vagal or esophageal stimulation. The measured conduction velocity of the afferent response was 7.5 m/s in epileptic subjects and 10 m/s in healthy controls, suggesting that afferent conduction is through A delta-fibers rather than slower C afferent fibers. We conclude that the cortical-evoked potential responses following esophageal electrical stimulation are comparable to direct electrical stimulation of the vagus nerve and involve mostly A delta-fibers. This approach provides a method for the assessment of vagal afferent gastrointestinal sensory pathways in health and disease.

Responses of medullary raphe neurons to electrical and chemical activation of vagal afferent nerve fibers

1993 ◽  
Vol 70 (5) ◽  
pp. 1950-1961 ◽  
Author(s):  
A. R. Evans ◽  
R. W. Blair
Keyword(s):  
Electrical Stimulation ◽  
Chemical Activation ◽  
Vagal Afferents ◽  
Frequency Dependent ◽  
Afferent Fibers ◽  
Vagal Afferent ◽  
Mixed Responses ◽  
Excitatory Responses ◽  
Dose Dependent ◽  
Stimulation Of

1. Various intensities, frequencies, and pulse widths of electrical stimulation of vagal afferent fibers were used to assess the responses of 87 medullary raphe neurons to vagal afferent fiber input in pentobarbital sodium-anesthetized, barodenervated paralyzed cats. Thirty-seven neurons were antidromically activated from the T2-T3 segments of the thoracic spinal cord, and 40 neurons could not be antidromically activated. Neurons were located in the nucleus raphe magnus (79%) and the nucleus raphe obscurus (15%). The remaining 6% of the neurons were not found; however, their locations were comparable in depth and position on the midline with other neurons in the same animals whose locations were identified. 2. The responses of 60 neurons to electrical stimulation of vagal afferent fibers were classified as excitatory (38%), inhibitory (24%), or mixed, (7%). The mixed responses were characterized by excitation at one frequency or intensity and inhibition at another frequency or intensity. The remaining 27 neurons did not clearly respond. 3. The excitatory responses to electrical stimulation of the cervical vagus nerve were intensity and frequency dependent. Inhibitory responses were frequency dependent at lower frequencies of stimulation and both frequency and intensity dependent at higher frequencies. The mixed responses were frequency dependent. Overall, longer pulse widths produced significantly greater responses than shorter pulse widths. 4. Thirty-three neurons were tested for responses to chemical stimulation of vagal afferents with intra-atrial injections of three doses of veratridine. Twenty-one percent were excited, 55% were inhibited, and 6% had mixed responses. For the mixed responses, excitation occurred at one dose and inhibition at another. The remaining 18% of the neurons were unresponsive to veratridine. The excitatory responses were dose dependent, but the inhibitory responses were not. Three doses of phenybiguanide (PBG) were also used to chemically activate vagal afferents in 27 neurons. Eleven percent were excited, 44% were inhibited, and 4% had mixed responses. The remaining 41% were unresponsive to PBG. The excitatory and inhibitory responses were dose dependent. 5. When comparing responses in projection and nonprojection neurons, inhibition was seen significantly more often in projection neurons and excitation in nonprojection neurons. Sixty-three percent of the neurons inhibited by electrical stimulation were raphespinal neurons, and 78% of the neurons excited by vagal stimulation were nonprojection neurons. Similar observations were made with the responses to chemical activation of the vagus. 6. Neurons with lower spontaneous discharge rates were more often excited by vagal stimulation and neurons with higher rates were more often inhibited.(ABSTRACT TRUNCATED AT 400 WORDS)

Responses of primate spinothalamic tract neurons to electrical stimulation of hindlimb peripheral nerves

1975 ◽  
Vol 38 (1) ◽  
pp. 132-145 ◽  
Author(s):  
R. D. Foreman ◽  
A. E. Applebaum ◽  
J. E. Beall ◽  
D. L. Trevino ◽  
W. D. Willis
Keyword(s):  
Electrical Stimulation ◽  
Mechanical Stimulation ◽  
Nerve Fibers ◽  
Mechanical Stimuli ◽  
Spinothalamic Tract ◽  
Antidromic Activation ◽  
Lumbosacral Spinal Cord ◽  
Afferent Fibers ◽  
To Receive ◽  
Stimulation Of

The responses of spinothalamic tract neurons were studied by extra- and intracellular recordings from the lumbosacral spinal cord in anesthetized rhesus monkeys (Macaca mulatta). The neurons were identified by antidromic activation from the contralateral diencephalon. They were then classified by the mildest form of mechanical stimulation applied to the ipsilateral hindlimb. The effects of electrical stimulation of the nerve(s) supplying the receptive field were investigated. Graded electrical stimulation revealed that the threshold responses of spinothalamic tract neurons excited by weak mechanical stimuli occurred when the largest afferent fibers were activated. On the other hand, neurons that required intense mechanical stimulation for their excitation tended to have higher thresholds to electrical stimulation. Some spinothalamic tract cells were shown to receive monosynaptic excitatory connections from peripheral nerve fibers, although polysynaptic connections may generally be more important. An input from unmyelinated afferent fibers was demonstrated. It is concluded the primate spinothalamic tract neurons receive a rich convergent input from a variety of cutaneous receptors. The experiments provide some evidence for the most likely types of receptors.

Difference in distribution of central terminals between visceral and somatic unmyelinated (C) primary afferent fibers

1989 ◽  
Vol 62 (4) ◽  
pp. 834-840 ◽  
Author(s):  
Y. Sugiura ◽  
N. Terui ◽  
Y. Hosoya
Keyword(s):  
Electrical Stimulation ◽  
Conduction Velocity ◽  
Nerve Conduction Velocity ◽  
Substantia Gelatinosa ◽  
Afferent Neurons ◽  
Celiac Ganglion ◽  
Afferent Fibers ◽  
Primary Afferent Fibers ◽  
Phaseolus Vulgaris Leucoagglutinin ◽  
Stimulation Of

1. In the guinea pig, the central projections of somatic and visceral C-afferent fibers were compared by tracing arborizations labeled through injection of Phaseolus vulgaris leucoagglutinin (PHA-L) intracellularly into single neurons of the 13th thoracic dorsal root ganglia (DRG). 2. Two of 27 somatic C-afferent neurons that responded to electrical stimulation of the 13th thoracic (subcostal) nerve (conduction velocity: 0.69 +/- 0.14 m/s, mean +/- SD) were well enough marked to allow delineation of their central processes. In both cases, the entering axon ran rostrally, giving off branches that converged on a single terminal field located in the substantia gelatinosa (lamina II) with some extension in lamina I. The terminal field in each case extended approximately 400 microns rostrocaudally and 100 microns mediolaterally. 3. Intracellular recordings were obtained from 31 afferent units that responded to electrical stimulation of the celiac ganglion. Units with onset latencies of greater than 15 ms were classified as having visceral C-afferent fibers because the shortest course from the celiac ganglion stimulation electrodes to the DRG was greater than 7 mm (i.e., a conduction velocity of less than 0.5 m/s). 4. Seven visceral C-afferent fibers were labeled well enough to follow their central trajectories. Each had a main ascending and a descending central branch. Each main branch in turn issued several collaterals that terminated in the superficial dorsal horn (laminae I and II), laminae IV, V, and X, and occasionally in the dorsal and lateral funiculi. A few collaterals reached the contralateral laminae V and X.(ABSTRACT TRUNCATED AT 250 WORDS)

Segmental organization of visceral and somatic input onto C3-T6 spinothalamic tract cells of the monkey

1992 ◽  
Vol 68 (5) ◽  
pp. 1575-1588 ◽  
Author(s):  
S. F. Hobbs ◽  
M. J. Chandler ◽  
D. C. Bolser ◽  
R. D. Foreman
Keyword(s):  
Spinal Cord ◽  
Electrical Stimulation ◽  
Urinary Bladder ◽  
Visceral Pain ◽  
Cell Activity ◽  
Afferent Input ◽  
Spinothalamic Tract ◽  
Afferent Fibers ◽  
Increased Activity ◽  
Stimulation Of

1. Referred pain of visceral origin has three major characteristics: visceral pain is referred to somatic areas that are innervated from the same spinal segments as the diseased organ; visceral pain is referred to proximal body regions and not to distal body areas; and visceral pain is felt as deep pain and not as cutaneous pain. The neurophysiological basis for these phenomena is poorly understood. The purpose of this study was to examine the organization of viscerosomatic response characteristics of spinothalamic tract (STT) neurons in the rostral spinal cord. Interactions were determined among the following: 1) segmental location, 2) effects of input by cardiopulmonary sympathetic, greater splanchnic, lumbar sympathetic, and urinary bladder afferent fibers, 3) location of excitatory somatic field, e.g., hand, forearm, proximal arm, or chest, 4) magnitude of response to hair, skin, and deep mechanoreceptor afferent input, and 5) regional specificity of thalamic projection sites. 2. A total of 89 STT neurons in segments C3-T6 were characterized for responses to visceral and somatic stimuli. Neurons were activated antidromically from the contralateral ventroposterolateral oralis or caudalis nuclei of the thalamus. Cell responses to visceral and somatic stimuli were not different on the basis of the thalamic site of antidromic activation. Recording sites for 61 neurons were located histologically; 87% of lesion sites were located in laminae IV-VII or X. There was no relationship between response properties of the neurons and spinal laminar location. 3. Different responses to visceral stimuli were observed in three zones of the rostral spinal cord: C3-C6, C7-C8, and T1-T6. In C3-C6, urinary bladder distension (UBD) and electrical stimulation of greater splanchnic and lumbar sympathetic afferent fibers inhibited STT cells. Electrical stimulation of cardiopulmonary sympathetic afferents increased cell activity in C5 and C6 and either excited or inhibited STT cells in C3 and C4. In the cervical enlargement (C7-C8), STT cells generally were either inhibited or showed little response to stimulation of visceral afferent fibers. In T1-T6, input from greater splanchnic and cardiopulmonary sympathetic afferent nerves increased activity of STT cells. Lumbar sympathetic afferent input inhibited cells in T1-T2 and had little effect on cells in T3-T6, whereas UBD decreased cell activity in all segments studied. 4. In general, stimulation of somatic structures increased activity of STT neurons in segments that received primary afferent innervation from the excitatory somatic receptive field or in the segments immediately adjacent to these segments. Only input from the forelimb, especially the hand, markedly excited cells in C7 and C8.+

Determination of afferent fibers mediating oligosynaptic group I input to cat medial gastrocnemius motoneurons

1985 ◽  
Vol 53 (2) ◽  
pp. 518-529 ◽  
Author(s):  
R. K. Powers ◽  
M. D. Binder
Keyword(s):  
Electrical Stimulation ◽  
Medial Gastrocnemius ◽  
Flexor Hallucis Longus ◽  
Selective Activation ◽  
Group I ◽  
Afferent Fibers ◽  
Series Of Experiments ◽  
Group Ii ◽  
Flexor Digitorum ◽  
Stimulation Of

In the experiments described in the preceding paper electrical stimulation of the quadriceps (QUAD), medial tibial (MTIB), and flexor digitorum and hallucis longus (FDHL) muscle nerves was used to evoke oligosynaptic group I postsynaptic potentials (PSPs) in medial gastrocnemius (MG) motoneurons. In the present study, we attempted to specify the types of afferent fibers which mediate that oligosynaptic activity (FDHL to MG only). In one series of experiments, isolated single flexor digitorum longus (FDL) and flexor hallucis longus (FHL) afferents were identified as Ia, Ib, or group II fibers according to their conduction velocities, responses to muscle contraction, and mechanical thresholds to small amplitude triangular stretches applied to the parent muscles. We also determined the electrical thresholds of the identified afferent fibers by applying graded electrical stimulation to their muscle nerve. These results were used as criteria to define the types of afferents that mediated the electrically and stretch-evoked FDHL oligosynaptic PSPs recorded in MG motoneurons during a second series of experiments. The amplitudes of the oligosynaptic PSPs evoked in MG motoneurons increased as the strength of the electrical stimuli applied to the FDHL muscle nerves was raised to activate greater numbers of Ia- and Ib-fibers, but showed little or no additional increase when the stimulus intensity was raised further to include the majority of group II fibers. On this basis, a significant contribution by group II fibers to these oligosynaptic PSPs was considered unlikely. Simultaneous electrical activation of both Ia- and Ib-fibers produced distinct oligosynaptic PSPs in MG motoneurons, but these were likely due primarily to Ib-afferent activity, since selective activation of Ia-afferents (by stretch) rarely produced oligosynaptic PSPs in the same motoneurons. There was, however, evidence for some Ia contribution to these oligosynaptic PSPs. This is consistent with the demonstration that Ia- and Ib-afferent fibers converge onto common interneurons and that selective activation of Ia-fibers can produce PSPs similar to those evoked by concurrent stimulation of Ia- and Ib-fibers. On the basis of the present results and those of several related studies it is argued that the oligosynaptic PSPs evoked in MG motoneurons by submaximal group I stimulation of the FDHL, MTIB, or QUAD muscle nerves can be ascribed predominantly to the activation of Ib-afferent fibers, with only minimal Ia and probably no group II contribution.

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