Retuning of segmental responses to peripheral stimulation in cats during fictitious locomotion

1982 ◽  
Vol 13 (3) ◽  
pp. 206-212 ◽  
Author(s):  
K. V. Baev
1986 ◽  
Vol 17 (3) ◽  
pp. 226-231 ◽  
Author(s):  
Yu. I. Arshavskii ◽  
E. S. Meizerov ◽  
G. N. Orlovskii ◽  
G. A. Pavlova ◽  
L. B. Popova

Cureus ◽  
2021 ◽  
Author(s):  
Jamal Hasoon ◽  
Ahish Chitneni ◽  
Ivan Urits ◽  
Omar Viswanath ◽  
Alan D Kaye

1967 ◽  
Vol 46 (3) ◽  
pp. 571-583
Author(s):  
M. B. V. ROBERTS

1. Three thresholds are demonstrated in the first segmental nerve and two (sometimes three) in the second and third segmental nerves together. 2. Slow potentials recorded from the ventral nerve cord consist of several peaks. The first peak is composed of three spikes which make their appearance at different thresholds. Transmission of at least some of the slow potentials is decremental. 3. Transmission speeds in the nerve cord and segmental nerves range from 0.4 to 0.6 m./sec. 4. Action potentials in the longitudinal muscle are recorded in response to slow potentials in the nerve cord. 5. Two slow reflexes, one involving elongation, the other longitudinal contraction, are described. The latter has the lower threshold with peripheral stimulation. 6. Slow activity in the nervous system is discussed in relation to reflex activity of the earthworm and the neurone anatomy of the nerve cord and segmental nerves.


1969 ◽  
Vol 50 (1) ◽  
pp. 129-140 ◽  
Author(s):  
M. S. LAVERACK

1. Mechanoreceptors in the body wall of the leech Hirudo are stimulated by deformation of the animal's surface. They respond at all frequencies of stimulation up to about 50-60 Hz. 2. Light flashes, from a microscope lamp or an electronic flash source, are also a potent means of peripheral stimulation. 3. After peripheral stimulation impulses can be recorded in a fast central pathway. This pathway conducts equally well in the posterior to anterior and in the opposite directions. 4. Interference with either the right or left connective linking any two segmental ganglia does not interrupt the rapid conduction of these impulses. 5. Severance of the median connective or Faivre's nerve interrupts conduction. This seems to implicate at least one, and possibly more, of the nerve fibres of this median connective in the rapid transmission of information from the extremities of the body. 6. A slower conducting pathway also exists in the nerve cord.


1996 ◽  
Vol 75 (4) ◽  
pp. 1753-1759 ◽  
Author(s):  
H. A. Swadlow ◽  
T. P. Hicks

1. Latencies to peripheral sensory stimulation were examined in four classes of antidromically identified efferent neurons in the primary somatosensory cortex (S1) of awake rabbits. Both suprathreshold responses (action potentials) and subthreshold responses were examined. Subthreshold responses were examined by monitoring the thresholds of efferent neurons to juxtasomal current pulses (JSCPs) delivered through the recording microelectrode (usually 1-3 microA). Through the use of this method, excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic potentials (IPSPs) were manifested as decreases and increases in threshold, respectively. Efferent populations examined included callosal (CC) neurons, ipsilateral corticocortical (C-IC) neurons, and descending corticofugal neurons of layer 5 (CF-5) and layer 6 (CF-6). Very brief air puffs (rise and fall times 0.6 ms) were delivered to the receptor periphery via a high-speed solenoid valve. 2. Whereas all CF-5 neurons had demonstrable suprathreshold excitatory and/or inhibitory responses to peripheral stimulation, most CC, C-IC, and CF-6 neurons did not. CC and CF-6 neurons that yielded no suprathreshold response to the stimulus had lower axonal conduction velocities than those that did respond (P < 0.0001 in both cases). However, subthreshold receptive fields could be demonstrated in many of the otherwise unresponsive CC (81%), C-IC (88%), and CF-6 (43%) neurons. The subthreshold responses usually consisted of an initial excitatory component (a decrease in the threshold to the JSCP) and a subsequent long-duration (> 80 ms) inhibitory component. A few neurons (1 CC, 1 C-IC, and 5 CF-6) showed an initial short latency inhibitory response in the absence of any excitatory component. 3. Some CC and C-IC neurons yielded supra- and/or subthreshold responses to peripheral stimulation at latencies of 6.1-7 ms. All such neurons were found at intermediate cortical depths (thought to correspond to deep layer 2-3 through layer 5). It is argued that such latencies are indicative of monosynaptic activation via thalamic afferents. Very superficial CC and C-IC neurons, and all CF-6 neurons responded to latencies of > 7 ms. All CF-5 neurons responded to latencies of > 8 ms, although many were found at the same depth as the deeper CC and C-IC neurons that responded at monosynaptic latencies. These results indicate that cortical cell type as well as laminar position are important factors that determine the sequence of intracortical neuronal activation after peripheral sensory stimulation.


2019 ◽  
Vol 23 (3) ◽  
pp. 312-323
Author(s):  
Giuseppe Lucente ◽  
Josep Valls‐Sole ◽  
Narda Murillo ◽  
John Rothwell ◽  
Jaume Coll ◽  
...  

1998 ◽  
Vol 80 (6) ◽  
pp. 3127-3136 ◽  
Author(s):  
K. M. Horn ◽  
T. M. Hamm ◽  
A. R. Gibson

Horn, K. M., T. M. Hamm, and A. R. Gibson. Red nucleus stimulation inhibits within the inferior olive. J. Neurophysiol. 80: 3127–3136, 1998. In the anesthetized cat, electrical stimulation of the magnocellular red nucleus (RNm) inhibits responses of rostral dorsal accessory olive (rDAO) neurons to cutaneous stimulation. We tested the hypothesis that RNm-mediated inhibition occurs within the inferior olive by using stimulation of the ventral funiculus (VF) of the spinal cord in place of cutaneous stimulation of the hindlimb. Fibers in the VF terminate on hindlimb rDAO neurons, so inhibition of this input would have to occur within the olive. rDAO responses elicited by VF stimulation were inhibited by prior stimulation of the RNm, indicating that inhibition occurs within the olive. In contrast, evoked potentials recorded from the VF or dorsal columns following hindlimb stimulation were not affected by prior stimulation of RNm, indicating that stimulation of the RNm does not inhibit olivary afferents at spinal levels. RNm stimulation that inhibited rDAO responses had little effect on evoked somatosensory responses in thalamus, indicating that inhibition generated by activity in RNm may be specific to rDAO. To test limb specificity of RNm-mediated inhibition, conditioning stimulation was applied to the dorsolateral funiculus at thoracic levels, which selectively activates RNm neurons projecting to the lumbar cord. Stimulation at thoracic levels inhibited evoked responses from hindlimb but not forelimb regions of rDAO, suggesting that inhibitory effects of RNm activity are limb specific. Several studies have reported that olivary neurons have reduced sensitivity to peripheral stimulation during movement; it is likely that RNm-mediated inhibition occurring within the olive contributes to this reduction of sensitivity. Inhibition of rDAO responses by descending motor pathways appears to be a salient feature of olivary function.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Carolina Reis ◽  
Beatriz S. Arruda ◽  
Alek Pogosyan ◽  
Peter Brown ◽  
Hayriye Cagnan

AbstractEssential tremor is a common neurological disorder, characterised by involuntary shaking of a limb. Patients are usually treated using medications which have limited effects on tremor and may cause side-effects. Surgical therapies are effective in reducing essential tremor, however, the invasive nature of these therapies together with the high cost, greatly limit the number of patients benefiting from them. Non-invasive therapies have gained increasing traction to meet this clinical need. Here, we test a non-invasive and closed-loop electrical stimulation paradigm which tracks peripheral tremor and targets thalamic afferents to modulate the central oscillators underlying tremor. To this end, 9 patients had electrical stimulation delivered to the median nerve locked to different phases of tremor. Peripheral stimulation induced a subtle but significant modulation in five out of nine patients—this modulation consisted mainly of amplification rather than suppression of tremor amplitude. Modulatory effects of stimulation were more pronounced when patient’s tremor was spontaneously weaker at stimulation onset, when significant modulation became more frequent amongst subjects. This data suggests that for selected individuals, a more sophisticated control policy entailing an online estimate of both tremor phase and amplitude, should be considered in further explorations of the treatment potential of tremor phase-locked peripheral stimulation.


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