Electrophysiological evidence for overlapping dominant and latent inputs to somatosensory cortex in squirrel monkeys

1995 ◽  
Vol 74 (2) ◽  
pp. 722-732 ◽  
Author(s):  
C. E. Schroeder ◽  
S. Seto ◽  
J. C. Arezzo ◽  
P. E. Garraghty
Keyword(s):  
Ulnar Nerve ◽  
Radial Nerve ◽  
Current Flow ◽  
Current Source ◽  
Squirrel Monkeys ◽  
Spatiotemporal Pattern ◽  
Nerve Section ◽  
Multiunit Activity ◽  
Preferential Access ◽  
Area 3B

1. The pattern of reorganization in area 3b of adult primates after median or ulnar nerve section suggests that somatic afferents from the dorsum of the hand, carried by the radial nerve, have preferential access to the cortical territories normally expressing glabrous inputs carried by the median and ulnar nerves. A likely mechanism underlying preferential access is preexisting, but silent, radial nerve inputs to the glabrous region of cortex. 2. We tested this by comparing the effects of electrical stimulation of median or ulnar versus radial nerves, on responses in the hand representation of area 3b. Laminar current source density and multiunit activity profiles were sampled with the use of linear array multicontact electrodes spanning the laminae of area 3b. Data were obtained from three squirrel monkeys anesthetized during recording. 3. Compared with colocated median or ulnar nerve responses, the radial nerve response had 1) an initial short-latency response in the middle laminae that was subtle; there was a small transmembrane current flow component without a discernable multiunit activity correlate; and 2) a laminar sequence and distribution of activity that was similar to those of the median or ulnar nerve responses (i.e., initial activation of the middle, followed by upper and lower laminae), but the significant current flow and multiunit response to radial nerve stimulation occurs 12–15 ms later. 4. Normal corepresentation of nondominant dorsum hand (radial) inputs with the dominant (median or ulnar) inputs in the glabrous hand surface representation provides a clear vehicle for the biased patterns of reorganization occurring after peripheral nerve section. The initial, “subtle” activity phase in the nondominant response is believed to reflect intracortical inhibition, and the later “significant” response phase, a rebound excitation, possibly compounded by an indirect or extralemniscal input. The spatiotemporal pattern of nondominant input is proposed to play a role in normal somatosensory perception.

Emergence of Radial Nerve Dominance in Median Nerve Cortex After Median Nerve Transection in an Adult Squirrel Monkey

1997 ◽  
Vol 77 (1) ◽  
pp. 522-526 ◽  
Author(s):  
C. E. Schroeder ◽  
S. Seto ◽  
P. E. Garraghty
Keyword(s):  
Median Nerve ◽  
Squirrel Monkey ◽  
Ulnar Nerve ◽  
Action Potentials ◽  
Radial Nerve ◽  
Current Source ◽  
Short Latency ◽  
Nerve Transection ◽  
A Site ◽  
Stimulation Of

Schroeder, C. E., S. Seto, and P. E. Garraghty. Emergence of radial nerve dominance in median nerve cortex after median nerve transection in an adult squirrel monkey. J. Neurophysiol. 77: 522–526, 1997. Throughout the glabrous representation in Area 3b, electrical stimulation of the dominant (median or ulnar) input produces robust, short-latency excitation, evident as a net extracellular “sink” in the Lamina 4 current source density (CSD) accompanied by action potentials. Stimulation of the collocated nondominant (radial nerve) input produces a subtle short-latency response in the Lamina 4 CSD unaccompanied by action potentials and followed by a clear excitatory response 12–15 ms later. Laminar response profiles for both inputs have a “feedforward” pattern, with initial activation in Lamina 4, followed by extragranular laminae. Such corepresentation of nondominant radial nerve inputs with the dominant (median or ulnar nerve) inputs in the glabrous hand surface representation provides a likely mechanism for reorganization after median nerve section in adult primates. To investigate this, we conducted repeated recordings using an implanted linear multi-electrode array straddling the cortical laminae at a site in “median nerve cortex” (i.e., at a site with a cutaneous receptive field on the volar surface of D2 and thus with its dominant afferent input conveyed by the median nerve) in an adult squirrel monkey. We characterized the baseline responses to median, radial, and ulnar nerve stimulation. We then cut the median nerve and semi-chronically monitored radial nerve, ulnar nerve and median nerve (proximal stump) evoked responses. The radial nerve response in median nerve cortex changed progressively during the weeks after median nerve transection, ultimately assuming the characteristics of the dominant nerve profile. During this time, median, and ulnar nerve profiles displayed little or no change.

Transfer of a Motor Fascicle From the Ulnar Nerve to the Branch of the Radial Nerve Destined to the Long Head of the Triceps for Restoration of Elbow Extension in Brachial Plexus Surgery

Neurosurgery ◽  
2011 ◽  
Vol 70 (2) ◽  
pp. E516-E520 ◽  
Author(s):  
Leandro Pretto Flores
Keyword(s):  
Computed Tomography ◽  
Brachial Plexus ◽  
Ulnar Nerve ◽  
Radial Nerve ◽  
Nerve Transfer ◽  
Elbow Flexion ◽  
Shoulder Abduction ◽  
Elbow Extension ◽  
Long Head ◽  
Brachial Plexus Surgery

Abstract BACKGROUND AND IMPORTANCE: Restoration of elbow extension has not been considered of much importance regarding functional outcomes in brachial plexus surgery; however, the flexion of the elbow joint is only fully effective if the motion can be stabilized, what can be achieved solely if the triceps brachii is coactivated. To present a novel nerve transfer of a healthy motor fascicle from the ulnar nerve to the nerve of the long head of the triceps to restore the elbow extension function in brachial plexus injuries involving the upper and middle trunks. CLINICAL PRESENTATION: Case 1 is a 32-year-old man sustaining a right brachial extended upper plexus injury in a motorcycle accident 5 months before admission. The computed tomography myelogram demonstrated avulsion of the C5 and C6 roots. Case 2 is a 24-year-old man who sustained a C5-C7 injury to the left brachial plexus in a traffic accident 4 months before admission. Computed tomography myelogram demonstrated signs of C6 and C7 root avulsion. The technique included an incision at the medial border of the biceps, in the proximal third of the involved arm, followed by identification of the ulnar nerve, the radial nerve, and the branch to the long head of the triceps. The proximal stump of a motor fascicle from the ulnar nerve was sutured directly to the distal stump of the nerve of the long head of the triceps. Techniques to restore elbow flexion and shoulder abduction were applied in both cases. Triceps strength Medical Research Council M4 grade was obtained in both cases. CONCLUSION: The attempted nerve transfer was effective for restoration of elbow extension in primary brachial plexus surgery; however, it should be selected only for cases in which other reliable donor nerves were used to restore elbow flexion.

scholarly journals Modeling of electrical characteristics of photo voltaic and effecting of cell parameters on V-I curve

2018 ◽  
Vol 7 (2.13) ◽  
pp. 276 ◽  
Author(s):  
Fawaz S. Abdullah ◽  
Safwan A. Hamoodi ◽  
Ali N. Hamoodi
Keyword(s):  
Current Flow ◽  
Current Source ◽  
Accurate Information ◽  
Electrical Characteristics ◽  
Solar Pv ◽  
Cell Parameters ◽  
Pv Systems ◽  
Photo Voltaic ◽  
Series Resistor ◽  
Advanced Model

Studding of PV systems in an active way needs accurate information of the power and voltage P-V current and voltage I-V characteristic curves of solar PV order. Therefore, this paper shows emulation of solar PV model utilizes Matlab/Simulink and practical results. This PV model depends on math’s equation and is explained during an equivalent circuit involving a photo current source, diode, shunt resistor and series resistor representing leakage current and series resistor expressing the inside losses because of the current flow. The advanced model let the prognosis of PV array manner under various circuit model and ecological parameters solar temperature, ray. A special model (Lcs M200 – JA/SI) solar collector using for this paper, results was compared with practical curve with different points of the curve and show good conformity to the model. 

Progression of change following median nerve section in the cortical representation of the hand in areas 3b and 1 in adult owl and squirrel monkeys

Neuroscience ◽  
1983 ◽  
Vol 10 (3) ◽  
pp. 639-665 ◽  
Author(s):  
M.M. Merzenich ◽  
J.H. Kaas ◽  
J.T. Wall ◽  
M. Sur ◽  
R.J. Nelson ◽  
...  
Keyword(s):  
Median Nerve ◽  
Squirrel Monkeys ◽  
Cortical Representation ◽  
Nerve Section

Direct and indirect visual inputs to superficial layers of cat superior colliculus: a current source-density analysis of electrically evoked potentials

1983 ◽  
Vol 49 (5) ◽  
pp. 1075-1091 ◽  
Author(s):  
B. Freeman ◽  
W. Singer
Keyword(s):  
Visual Cortex ◽  
Optic Nerve ◽  
Superior Colliculus ◽  
Current Source ◽  
Afferent Fiber ◽  
Synaptic Activity ◽  
Spatiotemporal Pattern ◽  
Visual Inputs ◽  
Electrolytic Lesions ◽  
Cat Superior Colliculus

1. The spatiotemporal pattern of visual inputs to the stratum griseum superficiale (SGS) and stratum opticum (SO) of the cat superior colliculus (SC) has been determined by an analysis of the current sinks occurring during postsynaptic activity following stimulation of each optic nerve (ON) and the optic chiasm (OX). Electrolytic lesions were used to determine the locations of the five major current sinks. 2. Direct SC afferents from the contralateral ON induced three current sinks whose maxima were located a) in the upper part of the SGS, b) in the middle part of the SGS, and c) in the lower part of the SGS and upper part of the SO. These three sinks were generated by three afferent fiber groups conducting in the optic nerve with modal and maximum velocities, respectively, of a) 4 and 5 m/s (slow W-group), b) 7 and 10 m/s (fast W-group), and c) 32 and 43 m/s (Y-group). 3. Indirect SC inputs from the contralateral ON via the ipsilateral visual cortex were identified by comparing the pattern of current sinks generated by OX stimulation before and after cortical ablation. The most prominent and fastest indirect sink (Y-group) was found in ;the lower half of the SGS and uppermost part of the SO. Low-amplitude, long-latency indirect current sinks were also found in the upper and lower thirds of the SGS. 4. The principal conclusions of this report are first, that the SGS is divisible into three physiologic regions according to the spatiotemporal pattern of excitatory synaptic activity generated by the afferent inputs and second, that there is a spatiotemporal matching of the direct collicular afferents from the contralateral retina and the indirect retinal afferents relaying through the ipsilateral visual cortex.

Peripheral Nervous SystemUpper Extremity

2013 ◽  
Author(s):  
Adam Fisch
Keyword(s):  
Nervous System ◽  
Brachial Plexus ◽  
Median Nerve ◽  
Peripheral Nervous System ◽  
Ulnar Nerve ◽  
Radial Nerve ◽  
Upper Extremities ◽  
Cervical Plexus

Chapter 3 discusses how to draw the peripheral nervous system (upper extremities), including the brachial plexus, median nerve, ulnar nerve, radial nerve, and the cervical plexus.

UPPER-EXTREMITY PERIPHERAL NERVE INJURIES

Neurosurgery ◽  
2009 ◽  
Vol 65 (suppl_4) ◽  
pp. A11-A17 ◽  
Author(s):  
Judith A. Murovic
Keyword(s):  
Upper Extremity ◽  
Ulnar Nerve ◽  
Action Potentials ◽  
Radial Nerve ◽  
Suture Repair ◽  
State University ◽  
Nerve Injuries ◽  
Louisiana State University ◽  
Nerve Action ◽  
Better Than

Abstract OBJECTIVE Data from three Louisiana State University Health Sciences Center (LSUHSC) publications were summarized for median, radial, and ulnar nerve injuries. METHODS Lesion types, repair techniques, and outcomes were compared for 1837 upper-extremity nerve lesions. RESULTS Sharp laceration injury repair outcomes at various levels for median and radial nerves were equally good (91% each) and better than those for the ulnar nerve (73%). Secondary suture and graft repair outcomes were better for the median nerve (78% and 68%, respectively) than for the radial nerve (69% and 67%, respectively) and ulnar nerve (69% and 56%, respectively). In-continuity lesions with positive nerve action potentials during intraoperative testing underwent neurolysis with good results for the median (97%), radial (98%), and ulnar nerves (94%). For radial, median, and ulnar nerve in-continuity lesions with negative intraoperative nerve action potentials, good results occurred after suture repair in 88%, 86%, and 75% and after graft repair in 86%, 75% and 56%, respectively. CONCLUSION Good outcomes after median and radial nerve repairs are attributable to the following factors: the median nerve's innervation of proximal, large finger, and thumb flexors; and the radial nerve's similar innervation of proximal muscles that do not perform delicate movements. This is contrary to the ulnar nerve's major nerve supply to the distal fine intrinsic hand muscles, which require more extensive innervation. The radial nerve also has a motor fiber predominance, reducing cross-motor/sensory reinnervation, and radial nerve-innervated muscles perform similar functions, decreasing the chance of innervation of muscles with opposite functions.

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