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.

scholarly journals Intraoperative monitoring for tethered cord surgery: an update

2004 ◽  
Vol 16 (2) ◽  
pp. E8 ◽  
Author(s):  
Karl F. Kothbauer ◽  
Klaus Novak
Keyword(s):  
Electrical Stimulation ◽  
Anal Sphincter ◽  
External Anal Sphincter ◽  
Continuous Monitoring ◽  
Pudendal Nerve ◽  
Tethered Cord ◽  
Sensory Pathways ◽  
Functional Integrity ◽  
Muscle Responses ◽  
Stimulation Of

Object Intraoperative neurophysiological recording techniques have found increasing use in neurosurgical practice. The development of new recording techniques feasible while the patient receives a general anesthetic have improved their practical use in a similar way to the use of digital recording, documentation, and video technology. This review intends to provide an update on the techniques used and their validity. Methods Two principal methods are used for intraoperative neurophysiological testing during tethered cord release. Mapping identifies functional neural structures, namely nerve roots, and monitoring provides continuous information on the functional integrity of motor and sensory pathways as well as reflex circuitry. Mapping is performed mostly by using direct electrical stimulation of a structure within the surgical field and recording at a distant site, usually a muscle. Sensory mapping can also be performed with peripheral stimulation and recording within the surgical site. Monitoring of the motor system is achieved with motor evoked potentials. These are evoked by transcranial electrical stimulation and recorded from limb muscles and the external anal sphincter. The presence or absence of muscle responses are the parameters monitored. Sensory potentials evoked by tibial or pudendal nerve stimulation and recorded from the dorsal columns via an epidurally inserted electrode and/or from the scalp as cortical responses are used to access the integrity of sensory pathways. Amplitudes and latencies of these responses are then interpreted. The bulbocavernosus reflex, with stimulation of the pudendal nerve and recording of muscle responses in the external anal sphincter, is used for continuous monitoring of the reflex circuitry. Presence or absence of this response is the pertinent parameter that is monitored. Conclusions Intraoperative neurophysiology provides a wide and reliable set of techniques for intraoperative identification of neural structures and continuous monitoring of their functional integrity.

Electrical stimulation of the primary somatosensory cortex inhibits spinal dorsal horn neuron activity

2005 ◽  
Vol 1057 (1-2) ◽  
pp. 134-140 ◽  
Author(s):  
Arun K. Senapati ◽  
Paula J. Huntington ◽  
Stacey C. LaGraize ◽  
Hilary D. Wilson ◽  
Perry N. Fuchs ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Somatosensory Cortex ◽  
Dorsal Horn ◽  
Spinal Dorsal Horn ◽  
Dorsal Horn Neuron ◽  
Neuron Activity ◽  
Spinal Dorsal ◽  
Spinal Dorsal Horn Neuron ◽  
Horn Neuron ◽  
Stimulation Of

Neural Responses to Electrical Stimulation of the Cochlea in Guinea Pigs

1994 ◽  
Vol 21 (4) ◽  
pp. 201-208
Author(s):  
Jun-Ichi Matsushima ◽  
Chihiro Harada ◽  
Noboru Sakai ◽  
Tohru Ifukube ◽  
Makoto Takahashi
Keyword(s):  
Electrical Stimulation ◽  
Guinea Pigs ◽  
Neural Responses ◽  
Stimulation Of

Production of Threshold Levels of Conscious Sensation by Electrical Stimulation of Human Somatosensory Cortex

1993 ◽  
pp. 1-34 ◽  
Author(s):  
B. Libet ◽  
W. W. Alberts ◽  
E. W. Wright ◽  
L. D. Delattre ◽  
G. Levin ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Somatosensory Cortex ◽  
Threshold Levels ◽  
Stimulation Of

Different effects of halothane on diaphragm and hindlimb muscle in rats

1987 ◽  
Vol 63 (5) ◽  
pp. 1757-1762 ◽  
Author(s):  
B. Dureuil ◽  
N. Viires ◽  
Y. Nivoche ◽  
M. Fiks ◽  
R. Pariente ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Phrenic Nerve ◽  
Muscle Function ◽  
Negative Inotropic Effect ◽  
Abdominal Pressure ◽  
Mechanically Ventilated ◽  
Diaphragmatic Muscle ◽  
Hindlimb Muscle ◽  
Supramaximal Stimulation ◽  
Stimulation Of

The effects of halothane administration on diaphragm and tibialis anterior (TA) muscle were investigated in 30 anesthetized mechanically ventilated rats. Diaphragmatic strength was assessed in 17 rats by measuring the abdominal pressure (Pab) generated during supramaximal stimulation of the intramuscular phrenic nerve endings at frequencies of 0.5, 30, and 100 Hz. Halothane was administered during 30 min at a constant minimum alveolar concentration (MAC): 0.5, 1, and 1.5 MAC in three groups of five rats. For each MAC, Pab was significantly reduced for all frequencies of stimulation except at 100 Hz during 0.5 MAC halothane exposure. The effects of halothane (0.5, 1, and 1.5 MAC) on diaphragmatic neuromuscular transmission were assessed in five other rats by measuring the integrated electrical activity of the diaphragm (Edi) during electrical stimulation of the phrenic nerve. No change in Edi was observed during halothane exposure. In five other rats TA contraction was studied by measuring the strength of isometric contraction of the muscle during electrical stimulation of its nerve supply at different frequencies (0.5, 30, and 100 Hz). Muscle function was unchanged during administration of halothane in a cumulative fashion from 0.5 to 1.5 MAC. These results demonstrate that halothane does not affect hindlimb muscle function, whereas it had a direct negative inotropic effect on rat diaphragmatic muscle.

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.

scholarly journals Submicroscopic Changes of the Nerve Endings in the Adrenal Medulla after Stimulation of the Splanchnic Nerve

1957 ◽  
Vol 3 (4) ◽  
pp. 611-614 ◽  
Author(s):  
Eduardo De Robertis ◽  
Alberto Vaz Ferreira
Keyword(s):  
Electrical Stimulation ◽  
Electron Microscope ◽  
Adrenal Medulla ◽  
Synaptic Vesicles ◽  
Splanchnic Nerve ◽  
The Other ◽  
Nerve Endings ◽  
The Mean ◽  
Increased Activity ◽  
Stimulation Of

The nerve endings of the adrenal medulla of the rabbit were studied under the electron microscope in the normal condition and after prolonged electrical stimulation of the splanchnic nerve. With a stimulus of 100 pulses per second for 10 minutes, there is an increase in the number of synaptic vesicles in the nerve ending. The mean number is of 82.6 vesicles per square micron in the normal and of 132.7 per square micron in the stimulated glands. With a stimulus of 400 pulses per second for 10 minutes, there is a considerable depletion of synaptic vesicles and other changes occur in the nerve endings. The mean number of vesicles is of 29.2 per square micron. These results are interpreted as indicative of an increased activity of the ending in one case, and as a diminished activity and fatigue of the synaptic junction in the other.

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.

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