scholarly journals Poussin's sign

2021 ◽  
Vol 25 (11) ◽  
pp. 1239-1239
Keyword(s):  
Motor Pathways ◽  
Reflex Arc ◽  
Extrapyramidal Motor

V. Dosuzkova and Th. Dosuzkov (Revue V. neurologii i psychiatrii, 1928, no. 4). In contrast to Babinsky, Leshchenko and Nemlicher (Proceedings of the Ukrainian psychoneur. Inst., 1927, III), the authors do not consider this reflex part of the fan sign, just as they do not find definite connections of this reflex with the setting and defense reflexes. Poussin occurs with the simultaneous defeat of the pyramidal and extrapyramidal motor pathways and disinhibition of the reflex arc of this reflex.

The Effects of Dynamic Visual Stimulation on Perception and Motor Control

1992 ◽  
Vol 2 (4) ◽  
pp. 285-295
Author(s):  
Fred H. Previc
Keyword(s):  
Visual Motion ◽  
Visual Stimulation ◽  
Visual Orientation ◽  
Manual Tracking ◽  
Postural Change ◽  
Motor Pathways ◽  
Spatial Disorientation ◽  
Motor Strategy ◽  
Research Findings ◽  
Extrapyramidal Motor

A set of research findings is described that deals with three principal laboratory measures of visual orientation (vection and postural and manual control). Two studies are highlighted, one of which compared the latencies of vection and visually induced postural change and the other of which investigated manual tracking under visually disorienting conditions. The first study showed that although vection and postural change are somewhat related to each other (for example, both were greater in response to roll and pitch as opposed to linear visual motion), the onset of vection is delayed by several seconds relative to the initiation of visually induced postural shifts. The second study showed that manual biases induced by visual roll motion are not overcome using a thumb-and-fore-finger (pyramidal) motor strategy, arid may not be equivalent to the “giant hand” illusion that is believed to reflect the predominance of the vestibulospinal (extrapyramidal) motor pathways during extreme spatial disorientation. These and other findings indicate that various visual orientation effects may involve at least partially independent mechanisms.

Continuous Intraoperative Neurophysiological Monitoring of the Motor Pathways Using Depth Electrodes During Surgical Resection of an Epileptogenic Lesion: A Novel Technique

2021 ◽  
Author(s):  
Denise F Chen ◽  
Jon T Willie ◽  
David Cabrera ◽  
Katie L Bullinger ◽  
Ioannis Karakis
Keyword(s):  
Motor Cortex ◽  
Surgical Resection ◽  
Radiation Necrosis ◽  
World Health ◽  
Intraoperative Neurophysiological Monitoring ◽  
Neurophysiological Monitoring ◽  
Epileptogenic Zone ◽  
Motor Pathways ◽  
Depth Electrodes ◽  
Epileptogenic Lesion

Abstract BACKGROUND AND IMPORTANCE Intraoperative neurophysiological monitoring of the motor pathways during epilepsy surgery is essential to safely achieve maximal resection of the epileptogenic zone. Motor evoked potential (MEP) recording is usually performed intermittently during resection using a handheld stimulator or continuously through an electrode array placed on the motor cortex. We present a novel variation of continuous MEP acquisition through previously implanted depth electrodes in the perirolandic cortex. CLINICAL PRESENTATION A 60-yr-old woman with a history of a left frontal meningioma (World Health Organization [WHO] grade II) treated with surgical resection and radiation presented with residual right hemiparesis and refractory epilepsy. Imaging demonstrated a perirolandic lesion with surrounding edema and mass effect in the prior surgical site, suspicious for radiation necrosis versus tumor recurrence. Presurgical electrocorticography (ECoG) with orthogonal, stereotactically implanted depth electrodes (stereoelectroencephalography [SEEG]) of the perirolandic cortex captured seizure onsets from the supplementary motor area (SMA) and primary motor cortex (PMC). The patient underwent a left frontal craniotomy for repeat resection and tissue diagnosis. Intraoperative ECoG and MEPs were obtained continuously with direct cortical stimulation through the indwelling SEEG electrodes in the PMC. Maximal resection was achieved with preservation of direct cortical MEPs and without deterioration of her baseline hemiparesis. Biopsy revealed radiation necrosis. At 30-mo follow-up, the patient had only rare seizures (Engel class IIB). CONCLUSION Intraoperative cortical MEP acquisition through implanted SEEG electrode arrays is a potentially safe and effective alternative approach to continuously monitor the motor pathways during the resection of a perirolandic epileptogenic lesion, without the need for surgical interruptions.

scholarly journals Cerebellar rTMS and PAS effectively induce cerebellar plasticity

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Martje G. Pauly ◽  
Annika Steinmeier ◽  
Christina Bolte ◽  
Feline Hamami ◽  
Elinor Tzvi ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Healthy Subjects ◽  
Primary Motor Cortex ◽  
Cortical Excitability ◽  
Motor Evoked Potentials ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Premotor Cortex ◽  
Motor Pathways ◽  
Non Invasive ◽  
Cerebellar Plasticity

AbstractNon-invasive brain stimulation techniques including repetitive transcranial magnetic stimulation (rTMS), continuous theta-burst stimulation (cTBS), paired associative stimulation (PAS), and transcranial direct current stimulation (tDCS) have been applied over the cerebellum to induce plasticity and gain insights into the interaction of the cerebellum with neo-cortical structures including the motor cortex. We compared the effects of 1 Hz rTMS, cTBS, PAS and tDCS given over the cerebellum on motor cortical excitability and interactions between the cerebellum and dorsal premotor cortex / primary motor cortex in two within subject designs in healthy controls. In experiment 1, rTMS, cTBS, PAS, and tDCS were applied over the cerebellum in 20 healthy subjects. In experiment 2, rTMS and PAS were compared to sham conditions in another group of 20 healthy subjects. In experiment 1, PAS reduced cortical excitability determined by motor evoked potentials (MEP) amplitudes, whereas rTMS increased motor thresholds and facilitated dorsal premotor-motor and cerebellum-motor cortex interactions. TDCS and cTBS had no significant effects. In experiment 2, MEP amplitudes increased after rTMS and motor thresholds following PAS. Analysis of all participants who received rTMS and PAS showed that MEP amplitudes were reduced after PAS and increased following rTMS. rTMS also caused facilitation of dorsal premotor-motor cortex and cerebellum-motor cortex interactions. In summary, cerebellar 1 Hz rTMS and PAS can effectively induce plasticity in cerebello-(premotor)-motor pathways provided larger samples are studied.

Supraspinal inhibition of a cutaneous vascular reflex in the cat

1964 ◽  
Vol 207 (2) ◽  
pp. 303-307 ◽  
Author(s):  
B. J. Prout ◽  
J. H. Coote ◽  
C. B. B. Downman
Keyword(s):  
Carotid Sinus ◽  
Spinal Reflexes ◽  
Descending Pathways ◽  
Skin Response ◽  
Reflex Arc ◽  
Vascular Reflex ◽  
Carotid Sinus Nerve Stimulation ◽  
Sympathetic Discharge ◽  
Stimulation Of ◽  
Cerebellar Stimulation

In cats anesthetized with chloralose-urethane mixture, stimulation of an afferent nerve evoked a vasoconstrictor reflex (VCR) and a galvanic skin response (GSR) in the pads of the feet. Stimulation of the ventromedial medullary reticular substance at the level of the obex abolished the VCR and the GSR. VCR could also be reduced by occlusion during prolonged stimulation of another spinal or visceral afferent pathway. Medulla stimulation was effective without itself causing a sympathetic discharge to the paw, showing that inhibition rather than occlusion was operative. Anterior cerebellar stimulation also inhibited the VCR. Carotid sinus nerve stimulation did not abolish the VCR. It is concluded that the effective mechanism includes a bulbospinal inhibitory path projecting on a spinal vasoconstrictor reflex arc. This arrangement is similar to the descending pathways inhibiting other spinal reflexes but the VCR-inhibitory path can be activated independently of them.

scholarly journals Ipsilateral Motor Pathways and Transcallosal Inhibition During Lower Limb Movement After Stroke

2021 ◽  
pp. 154596832199904
Author(s):  
Brice T. Cleland ◽  
Sangeetha Madhavan
Keyword(s):  
Lower Limb ◽  
Functional Outcomes ◽  
Motor Pathways ◽  
Movement Accuracy ◽  
Transcallosal Inhibition ◽  
Paretic Limb ◽  
Bilateral Lower Limb ◽  
Ankle Movement ◽  
Lower Limb Movement ◽  
Clinical Measures

Background Stroke rehabilitation may be improved with a better understanding of the contribution of ipsilateral motor pathways to the paretic limb and alterations in transcallosal inhibition. Few studies have evaluated these factors during dynamic, bilateral lower limb movements, and it is unclear whether they relate to functional outcomes. Objective Determine if lower limb ipsilateral excitability and transcallosal inhibition after stroke depend on target limb, task, or number of limbs involved, and whether these factors are related to clinical measures. Methods In 29 individuals with stroke, ipsilateral and contralateral responses to transcranial magnetic stimulation were measured in the paretic and nonparetic tibialis anterior during dynamic (unilateral or bilateral ankle dorsiflexion/plantarflexion) and isometric (unilateral dorsiflexion) conditions. Relative ipsilateral excitability and transcallosal inhibition were assessed. Fugl-Meyer, ankle movement accuracy, and walking characteristics were assessed. Results Relative ipsilateral excitability was greater during dynamic than isometric conditions in the paretic limb ( P ≤ .02) and greater in the paretic than the nonparetic limb during dynamic conditions ( P ≤ .004). Transcallosal inhibition was greater in the ipsilesional than contralesional hemisphere ( P = .002) and during dynamic than isometric conditions ( P = .03). Greater ipsilesional transcallosal inhibition was correlated with better ankle movement accuracy ( R2 = 0.18, P = .04). Greater contralateral excitability to the nonparetic limb was correlated with improved walking symmetry ( R2 = 0.19, P = .03). Conclusions Ipsilateral pathways have increased excitability to the paretic limb, particularly during dynamic tasks. Transcallosal inhibition is greater in the ipsilesional than contralesional hemisphere and during dynamic than isometric tasks. Ipsilateral pathways and transcallosal inhibition may influence walking asymmetry and ankle movement accuracy.

Intragastric administration of capsiate, a transient receptor potential channel agonist, triggers thermogenic sympathetic responses

2011 ◽  
Vol 110 (3) ◽  
pp. 789-798 ◽  
Author(s):  
Kaori Ono ◽  
Masako Tsukamoto-Yasui ◽  
Yoshiko Hara-Kimura ◽  
Naohiko Inoue ◽  
Yoshihito Nogusa ◽  
...  
Keyword(s):  
Sympathetic Nerve ◽  
Transient Receptor Potential ◽  
Trp Channels ◽  
Low Frequency ◽  
Receptor Potential ◽  
Transient Receptor Potential Channel ◽  
Intragastric Administration ◽  
Brown Adipose ◽  
Reflex Arc ◽  
Transient Receptor

The sympathetic thermoregulatory system controls the magnitude of adaptive thermogenesis in correspondence with the environmental temperature or the state of energy intake and plays a key role in determining the resultant energy storage. However, the nature of the trigger initiating this reflex arc remains to be determined. Here, using capsiate, a digestion-vulnerable capsaicin analog, we examined the involvement of specific activation of transient receptor potential (TRP) channels within the gastrointestinal tract in the thermogenic sympathetic system by measuring the efferent activity of the postganglionic sympathetic nerve innervating brown adipose tissue (BAT) in anesthetized rats. Intragastric administration of capsiate resulted in a time- and dose-dependent increase in integrated BAT sympathetic nerve activity (SNA) over 180 min, which was characterized by an emergence of sporadic high-activity phases composed of low-frequency bursts. This increase in BAT SNA was abolished by blockade of TRP channels as well as of sympathetic ganglionic transmission and was inhibited by ablation of the gastrointestinal vagus nerve. The activation of SNA was delimited to BAT and did not occur in the heart or pancreas. These results point to a neural pathway enabling the selective activation of the central network regulating the BAT SNA in response to a specific stimulation of gastrointestinal TRP channels and offer important implications for understanding the dietary-dependent regulation of energy metabolism and control of obesity.

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