scholarly journals The relation between maximal voluntary force in m. palmaris longus and the temporal and spatial summation of muscle fiber recruitment in human subjects

2018 ◽  
Vol 6 (1) ◽  
pp. e13580 ◽  
Author(s):  
Cécyl G. Claudel ◽  
Waqas Ahmed ◽  
Vibeke S. Elbrønd ◽  
Adrian P. Harrison ◽  
Else Marie Bartels
Keyword(s):  
Muscle Fiber ◽  
Human Subjects ◽  
Spatial Summation ◽  
Maximal Voluntary Force ◽  
Palmaris Longus ◽  
Temporal And Spatial

scholarly journals Effect of racemic mixture and the (S+)-isomer of ketamine on temporal and spatial summation of pain

1996 ◽  
Vol 77 (5) ◽  
pp. 625-631 ◽  
Author(s):  
L Arendt-Nielsen ◽  
J Nielsen ◽  
S Petersen-Felix ◽  
T W Schnider ◽  
A M Zbinden
Keyword(s):  
Spatial Summation ◽  
Racemic Mixture ◽  
Temporal And Spatial

Neural Responses in the Macaque V1 to Bar Stimuli With Various Lengths Presented on the Blind Spot

2005 ◽  
Vol 93 (5) ◽  
pp. 2374-2387 ◽  
Author(s):  
Masayuki Matsumoto ◽  
Hidehiko Komatsu
Keyword(s):  
Human Subjects ◽  
Receptive Fields ◽  
Spatial Summation ◽  
Blind Spot ◽  
Neural Responses ◽  
Contextual Modulation ◽  
V1 Neurons ◽  
Retinal Stimulation ◽  
Perceptual Completion ◽  
Fixation Task

Although there is no retinal input within the blind spot, it is filled with the same visual attributes as its surround. Earlier studies showed that neural responses are evoked at the retinotopic representation of the blind spot in the primary visual cortex (V1) when perceptual filling-in of a surface or completion of a bar occurs. To determine whether these neural responses correlate with perception, we recorded from V1 neurons whose receptive fields overlapped the blind spot. Bar stimuli of various lengths were presented at the blind spots of monkeys while they performed a fixation task. One end of the bar was fixed at a position outside the blind spot, and the position of the other end was varied. Perceived bar length was measured using a similar set of bar stimuli in human subjects. As long as one end of the bar was inside the blind spot, the perceived bar length remained constant, and when the bar exceeded the blind spot, perceptual completion occurred, and the perceived bar length increased substantially. Some V1 neurons of the monkey exhibited a significant increase in their activity when the bar exceeded the blind spot, even though the amount of the retinal stimulation increased only slightly. These response increases coincided with perceptual completion observed in human subjects and were much larger than would be expected from simple spatial summation and could not be explained by contextual modulation. We conclude that the completed bar appearing on the part of the receptive field embedded within the blind spot gave rise to the observed increase in neuronal activity.

Effect of expiratory loading on expiratory duration and pulmonary stretch receptor discharge

1986 ◽  
Vol 61 (5) ◽  
pp. 1857-1863 ◽  
Author(s):  
P. W. Davenport ◽  
J. A. Wozniak
Keyword(s):  
Linear Relationship ◽  
Temporal Summation ◽  
Spatial Summation ◽  
Stretch Receptor ◽  
Single Breath ◽  
Stretch Receptors ◽  
Pulmonary Stretch Receptors ◽  
Temporal And Spatial ◽  
Resistive Loads ◽  
Pulmonary Stretch Receptor

Slowly adapting pulmonary stretch receptors have been hypothesized to be the afferents mediating the vagally dependent, volume-related prolongation of expiratory time (TE) during expiratory loading. It has been further suggested that the vagal component of this prolongation of TE is due to the temporal summation of pulmonary stretch receptor (PSR) activity during expiratory loading. This hypothesis was tested in rabbits exposed to resistive and elastic single-breath expiratory loading while PSR′s were simultaneously recorded. Both types of loads resulted in a decreased expired volume (VE) and increased expiratory duration (TE). The TE for resistive loads were significantly greater than for elastic loads for equivalent VE. Thus two different VE-TE relationships were found for resistive and elastic loads. When TE was plotted against the area under the expired volume trajectory, a single linear relationship was observed. PSR activity recorded during expiratory loading increased as VE decreased and TE increased. A single linear relationship resulted when the number of PSR spikes during the expiration was plotted against the associated TE for all types of loads. These findings demonstrate that the volume-related prolongation of TE with single-breath expiratory loads is associated with an increase in PSR discharge. These results support the hypothesis that the vagal component of load-dependent prolongation of TE is a function of both the temporal and spatial summation of PSR activity during the expiratory phase.

scholarly journals Motor–sensory convergence in object localization: a comparative study in rats and humans

2011 ◽  
Vol 366 (1581) ◽  
pp. 3070-3076 ◽  
Author(s):  
Guy Horev ◽  
Avraham Saig ◽  
Per Magne Knutsen ◽  
Maciej Pietr ◽  
Chunxiu Yu ◽  
...  
Keyword(s):  
Comparative Study ◽  
Human Subjects ◽  
Tactile Perception ◽  
Object Localization ◽  
Object Location ◽  
Sensory Inputs ◽  
Spatial Alignment ◽  
Sensory Convergence ◽  
Temporal And Spatial ◽  
Sensory Process

In order to identify basic aspects in the process of tactile perception, we trained rats and humans in similar object localization tasks and compared the strategies used by the two species. We found that rats integrated temporally related sensory inputs (‘temporal inputs’) from early whisk cycles with spatially related inputs (‘spatial inputs’) to align their whiskers with the objects; their perceptual reports appeared to be based primarily on this spatial alignment. In a similar manner, human subjects also integrated temporal and spatial inputs, but relied mainly on temporal inputs for object localization. These results suggest that during tactile object localization, an iterative motor–sensory process gradually converges on a stable percept of object location in both species.

Innervation Territories of Mechanically Activated C Nociceptor Units in Human Skin

1997 ◽  
Vol 78 (5) ◽  
pp. 2641-2648 ◽  
Author(s):  
Roland Schmidt ◽  
Martin Schmelz ◽  
Matthias Ringkamp ◽  
Hermann O. Handwerker ◽  
H. Erik Torebjörk
Keyword(s):  
Human Skin ◽  
Peroneal Nerve ◽  
Human Subjects ◽  
Receptive Fields ◽  
Spatial Summation ◽  
Lower Leg ◽  
Mechanical Stimuli ◽  
Axon Reflex ◽  
C Fibers ◽  
Noxious Stimuli

Schmidt, Roland, Martin Schmelz, Matthias Ringkamp, Hermann O. Handwerker, and H. Erik Torebjörk. Innervation territories of mechanically activated C nociceptor units in human skin. J. Neurophysiol. 78: 2641–2648, 1997. Innervation territories of single mechanically activated C nociceptors in the skin of the leg and foot were explored in normal human subjects. Microneurographic recordings were obtained in the peroneal nerve from 70 mechano-heat responsive (CMH) and 7 mechano-(but not heat) responsive (CM) units. Units were identified by their constant long-latency response to intracutaneous electrical stimulation of their terminals. Responsiveness to mechanical, heat, or transcutaneous electrical stimuli was verified by transient slowing of conduction velocity after activation by such stimuli. We determined their thresholds to mechanical stimuli (mean 33.7 mN, median 30 mN, range 3–750 mN) and heat (mean 42.5°C, median 42.5°C, range 37–49°C). Most mechano-receptive fields (mRFs) were found on the foot dorsum (60 units) and some on the lower leg (14 units) and toes (3 units). Most units had one continuous mRF, but 10 units had more complex fields. Areas of mRFs mapped with a von Frey filament (750 mN) ranged from 10 to 363 mm2 (mean, 106 mm2). The mRFs were oval or irregularly shaped with greatest diameters ranging from 3 to 45 mm. Mean areas of mRFs were largest on the lower leg (198 mm2), smaller on the foot dorsum (88 mm2), and smallest on the toes (35 mm2). Forty-nine of the 77 units had identical mRFs and electro-receptive fields (eRFs). Twenty-six units had larger eRFs than mRFs, whereas the opposite was found for two units only. Areas of eRFs ranged from 16 to 511 mm2 (mean 121 mm2). An estimate of the innervation density based on the present data and the presumed number of C fibers in cutaneous fascicles of the peroneal nerve suggests a considerable overlap of nociceptive endings in the skin. Such overlapping nociceptor innervation in the skin allows for substantial spatial summation in response to punctate noxious stimuli, which may be a prerequisite for high accuracy in localizing painful events from a C-fiber input. The reduction in size of innervation territories distally allows for finer discrimination of spatial dimensions of noxious stimuli distally as compared with proximal regions of the extremities. Mean maximal diameters of the mechano-receptive fields of CMH and CM units on the lower leg (22.3 mm) and foot (15.3 mm) are of similar size as the radius of axon reflex flares evoked by noxious mechanical stimuli in these regions.

scholarly journals Temporal and spatial summation in the human rod visual system.

1993 ◽  
Vol 463 (1) ◽  
pp. 325-348 ◽  
Author(s):  
L T Sharpe ◽  
A Stockman ◽  
C C Fach ◽  
U Markstahler
Keyword(s):  
Visual System ◽  
Spatial Summation ◽  
Temporal And Spatial
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