Response to Dr Elliot Shevel’s comment on the Editorial ‘The trigeminovascular system does not require a peripheral sensory input to be activated—migraine is a central disorder’

Cephalalgia ◽  
2012 ◽  
Vol 32 (14) ◽  
pp. 1082-1083
Author(s):  
Simon Akerman ◽  
Peter J Goadsby
Keyword(s):  
Sensory Input ◽  
Trigeminovascular System ◽  
Central Disorder ◽  
Peripheral Sensory

Peripheral control of the gain of a central synaptic connection between antagonistic motor neurones in the locust

1996 ◽  
Vol 199 (3) ◽  
pp. 613-625
Author(s):  
T Jellema ◽  
W Heitler
Keyword(s):  
Muscle Contraction ◽  
Sensory Input ◽  
Sense Organ ◽  
Gain Control ◽  
Motor Neurone ◽  
Extensor Muscle ◽  
Chordotonal Organ ◽  
Excitatory Postsynaptic Potential ◽  
Motor Neurones ◽  
Peripheral Sensory

The metathoracic fast extensor tibiae (FETi) motor neurone of locusts is unusual amongst insect motor neurones because it makes output connections within the central nervous system as well as in the periphery. It makes excitatory chemical synaptic connections to most if not all of the antagonist flexor tibiae motor neurones. The gain of the FETi-flexor connection is dependent on the peripheral conditions at the time of the FETi spike. This dependency has two aspects. First, sensory input resulting from the extensor muscle contraction can sum with the central excitatory postsynaptic potential (EPSP) to augment its falling phase if the tibia is restrained in the flexed position (initiating a tension-dependent reflex) or is free to extend (initiating a movement-dependent resistance reflex). This effect is thus due to simple postsynaptic summation of the central EPSP with peripheral sensory input. Second, the static tibial position at the time of the FETi spike can change the amplitude of the central EPSP, in the absence of any extensor muscle contraction. The EPSP can be up to 30 % greater in amplitude if FETi spikes with the tibia held flexed rather than extended. The primary sense organ mediating this effect is the femoral chordotonal organ. Evidence is presented suggesting that the mechanism underlying this change in gain may be specifically localised to the FETi-flexor connection, rather than being due to general position-dependent sensory feedback summing with the EPSP. The change in the amplitude of the central EPSP is probably not caused by general postsynaptic summation with tonic sensory input, since a diminution in the amplitude of the central EPSP caused by tibial extension is often accompanied by overall tonic excitation of the flexor motor neurone. Small but significant changes in the peak amplitude of the FETi spike have a positive correlation with changes in the EPSP amplitude, suggesting a likely presynaptic component to the mechanism of gain control. The change in amplitude of the EPSP can alter its effectiveness in producing flexor motor output and, thus, has functional significance. The change serves to augment the effectiveness of the FETi-flexor connection when the tibia is fully flexed, and thus to increase its adaptive advantage during the co-contraction preceding a jump or kick, and to reduce the effectiveness of the connection when the tibia is partially or fully extended, and thus to reduce its potentially maladaptive consequences during voluntary extension movements such as thrusting.

scholarly journals A bipedal mammalian model for spinal cord injury research: The tammar wallaby

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 921 ◽  
Author(s):  
Norman R. Saunders ◽  
Katarzyna M. Dziegielewska ◽  
Sophie C. Whish ◽  
Lyn A. Hinds ◽  
Benjamin J. Wheaton ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Sensory Input ◽  
Tammar Wallaby ◽  
Muscle Coordination ◽  
Thoracic Spinal Cord ◽  
Hind Limbs ◽  
Cord Injury ◽  
Trunk Posture ◽  
Peripheral Sensory

Background: Most animal studies of spinal cord injury are conducted in quadrupeds, usually rodents. It is unclear to what extent functional results from such studies can be translated to bipedal species such as humans because bipedal and quadrupedal locomotion involve very different patterns of spinal control of muscle coordination. Bipedalism requires upright trunk stability and coordinated postural muscle control; it has been suggested that peripheral sensory input is less important in humans than quadrupeds for recovery of locomotion following spinal injury. Methods: We used an Australian macropod marsupial, the tammar wallaby (Macropus eugenii), because tammars exhibit an upright trunk posture, human-like alternating hindlimb movement when swimming and bipedal over-ground locomotion. Regulation of their muscle movements is more similar to humans than quadrupeds. At different postnatal (P) days (P7–60) tammars received a complete mid-thoracic spinal cord transection. Morphological repair, as well as functional use of hind limbs, was studied up to the time of their pouch exit. Results: Growth of axons across the lesion restored supraspinal innervation in animals injured up to 3 weeks of age but not in animals injured after 6 weeks of age. At initial pouch exit (P180), the young injured at P7-21 were able to hop on their hind limbs similar to age-matched controls and to swim albeit with a different stroke. Those animals injured at P40-45 appeared to be incapable of normal use of hind limbs even while still in the pouch. Conclusions: Data indicate that the characteristic over-ground locomotion of tammars provides a model in which regrowth of supraspinal connections across the site of injury can be studied in a bipedal animal. Forelimb weight-bearing motion and peripheral sensory input appear not to compensate for lack of hindlimb control, as occurs in quadrupeds. Tammars may be a more appropriate model for studies of therapeutic interventions relevant to humans.

Henry Head’s lifelong studies of cutaneous sensation

2020 ◽  
pp. 096777202094055
Author(s):  
Michael Swash
Keyword(s):  
Brain Function ◽  
Sensory Input ◽  
Sensory Nerve ◽  
Afferent Pathways ◽  
Histological Techniques ◽  
Cutaneous Sensation ◽  
Cutaneous Branch ◽  
Conceptual Problems ◽  
Peripheral Sensory ◽  
Important Stimulus

In 1900 research on cutaneous sensation was defined by histological techniques defining sensory receptors in skin, leading to undetermined conceptual problems when considered in relation to Brown-Séquard’s startling finding that there were two qualitatively different afferent pathways in the spinal cord. Four modalities were considered to function as the determinants of sensory input. In 1903 Rivers and Head carried out the first interventional study of human cutaneous sensation, and analysed the return of sensation following section and immediate suture of the dorsal cutaneous branch of Head’s left radial nerve. This resulted in the revolutionary idea summarised in his description of protopathic and epicritic sensory systems in peripheral sensory nerve. Although this concept was at best seen as controversial and even ridiculed by some of his many contemporaneous critics, more recently this concept has proven a fundamentally important stimulus to understanding the physiology of cutaneous sensation. His writings show him to have been capable of deeply instructive thought, based on his clinical experience and his admiration of Hughlings Jackson’s teaching concerning the hierarchical organisation of brain function. First and foremost a clinician neuroscientist, his ideas were ahead of their time and not understood.

Fixation of spinal reflexes in rats by central and peripheral sensory input.

1981 ◽  
Vol 95 (4) ◽  
pp. 548-555 ◽  
Author(s):  
Joseph E. Steinmetz ◽  
Charles Robinson ◽  
Jean Cervenka ◽  
Anthony G. Romano ◽  
Michael M. Patterson
Keyword(s):  
Sensory Input ◽  
Spinal Reflexes ◽  
Peripheral Sensory

scholarly journals Effects of supraspinal feedback on human gait: rhythmic auditory distortion

2019 ◽  
Vol 16 (1) ◽  
Author(s):  
Arturo Forner-Cordero ◽  
João Pedro Pinho ◽  
Guilherme Umemura ◽  
João Carlos Lourenço ◽  
Bruno Mezêncio ◽  
...  
Keyword(s):  
Sensory Input ◽  
Relative Phase ◽  
Optical Measurement ◽  
Human Gait ◽  
Low Frequencies ◽  
Motion Data ◽  
The Mean ◽  
Contact Response ◽  
Peripheral Sensory ◽  
Lead Error

Abstract Background Different types of sound cues have been used to adapt the human gait rhythm. We investigated whether young healthy volunteers followed subliminal metronome rhythm changes during gait. Methods Twenty-two healthy adults walked at constant speed on a treadmill following a metronome sound cue (period 566 msec). The metronome rhythm was then either increased or decreased, without informing the subjects, at 1 msec increments or decrements to reach, respectively, a low (596 msec) or a high frequency (536 msec) plateaus. After 30 steps at one of these isochronous conditions, the rhythm returned to the original period with decrements or increments of 1 msec. Motion data were recorded with an optical measurement system to determine footfall. The relative phase between sound cue (stimulus) and foot contact (response) were compared. Results Gait was entrained to the rhythmic auditory stimulus and subjects subconsciously adapted the step time and length to maintain treadmill speed, while following the rhythm changes. In most cases there was a lead error: the foot contact occurred before the sound cue. The mean error or the absolute mean relative phase increased during the isochronous high (536 msec) or low frequencies (596 msec). Conclusion These results showed that the gait period is strongly “entrained” with the first metronome rhythm while subjects still followed metronome changes with larger error. This suggests two processes: one slow-adapting, supraspinal oscillator with persistence that predicts the foot contact to occur ahead of the stimulus, and a second fast process linked to sensory inputs that adapts to the mismatch between peripheral sensory input (foot contact) and supraspinal sensory input (auditory rhythm).

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