Transcutaneous trigeminal nerve stimulation modulates the hand blink reflex (original) (raw)
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Journal of Neurology, Neurosurgery & Psychiatry, 1992
Changes in the size ofthe test components (RI and R2) of the trigemino-facial reflex were studied after electrical subliminal conditioning stimulation were applied to the trigeminal, median and sural nerves. After conditioning activation of the trigeminal nerve (below the reflex threshold), the early RI reflex component showed phasic facilitation, peaking at about 50 ms of interstimulus delay, followed by a long-lasting inhibition recovering at 300-400 ms. The same conditioning stimulation resulted in a monotonic inhibition of the late R2, starting at 15-20 ms, with a maximum at 100-150 ms and lasting 300-400 ms. Intensity thresh
Pain Research and Management, 2021
Trigeminal neuralgia is often misdiagnosed at initial presentation due to close connotation with dental pain and is often over diagnosed for the very same reasons leading to numerous unnecessary surgical procedures such as peripheral neurectomy and alcohol injections, while the actual cause may remain elusive for decades. Evaluation of the neurosensory system may disclose the correct anatomical location of the etiology. The neurological examination may be clouded by the sensory deficits subsequent to previous peripheral surgical procedures. The corneal and blink reflexes are integral measures of the trigeminal and facial neurosensory assessment, and their abnormal function may facilitate the identification of intrinsic disease of the brain stem. These reflexes can be employed to discover pathological lesions including intracranial space-occupying trigeminal, lateral medullary, cerebral hemispheric lesions, and degenerative diseases of the central nervous system. Dental surgeons and ...
Clinical Neurophysiology, 2001
Objectives: Patients with peripheral facial palsy (PFP) may present with transient hyperkinetic movement disorders in the side contralateral to the paralysis. One possible cause of such enhanced motor activity is sensitization of re¯ex responses to afferent inputs from the unprotected cornea. We hypothesized that if this sensitization occurs, the size of the orbicularis oculi (OOc) responses induced by afferents from the ophthalmic branch of the paralyzed side would be larger than those induced by afferents from the contralateral side.
Trigemino‐facial reflex inhibitory responses in some lower facial muscles
Muscle & Nerve, 2000
The effects of electrical trigeminal stimulation on activated facial muscles were studied in 20 normal subjects in order to evaluate whether excitatory or inhibitory responses are present and to investigate whether the reflex organization is similar in all the facial muscles. No inhibition was observed in frontalis, orbicularis oculi, orbicularis oris, and mentalis muscles. By contrast, a clear suppression of electromyographic (EMG) activity (late silent period or SP2) was present in the levator labii superioris, depressor anguli oris, and depressor labii inferioris muscles, with a mean latency ranging from 41.8 to 50.2 ms, and a mean duration ranging from 27.5 to 40.9 ms. An early suppression of EMG activity (early silent period or SP1) was observed, with a latency of 16 to 20 ms and a duration of 10 ms, mainly in inferior perioral muscles. Our findings show a selective trigeminal inhibitory influence upon some specific lower facial muscles.
Electroencephalography and Clinical Neurophysiology, 1989
Ten successive experiments were carried out in 10 volunteers to compare the physiological properties of R2 and R3 components of the blink reflex. The electrical activation threshold of the R3 component was found to be significantly higher than that of the R2 response and was more susceptible to anaesthetic blocking of the peripheral afferents. This result suggests that the R3 component is induced by the activation of a different population of peripheral afferents from the R2 component. A recovery cycle study performed using a double stimulus showed that R3 is inhibited to a greater extent and for a longer time than R2. The temporal relationship of R3 to the voluntarily produced blink demonstrates that R3 is not a voluntary response to electrical stimulation. In conclusion, these experiments support the existence of an independent R3 component and its relationship with the activation of small diameter and higher threshold afferent fibres, perhaps nociceptive ones.
Electrically Induced Blink Reflex and Facial Motor Nerve Stimulation in Beagles
Journal of Veterinary Internal Medicine, 2000
Electrophysiologic assessment of the blink reflex test and the muscle-evoked potentials evoked by stimulation of the facial nerve were performed in 15 healthy adult Beagles before and after supraorbital (trigeminal) and facial anesthetic nerve blocks performed by lidocaine injections. Unilateral electrical stimulation of the supraorbital nerve elicited 2 ipsilateral (R 1 and R 2 ) and a contralateral (R c ) reflex muscle potential in orbicularis oculi muscles. Electrical stimulation of the facial nerve elicited 2 muscle potentials (a direct response [D] and a reflex faciofacial response [RF]) in the ipsilateral orbicularis oculi muscle. Anesthetic block of the left supraorbital nerve resulted in bilateral lack of responses upon left supraorbital nerve stimulation, but normal responses in right and left orbicularis oculi muscles upon right supraorbital stimulation. Right facial anesthetic block produced lack of responses in the right orbicularis oculi muscle regardless the side of supraorbital nerve stimulation. Results of this study demonstrate that the blink reflex can be electrically elicited and assessed in dogs. Reference values for the blink reflex responses and for the muscle potentials evoked by direct facial nerve stimulation in dogs are provided. The potential usefulness of the electrically elicited blink reflex test in the diagnosis of peripheral facial and trigeminal dysfunction in dogs was demonstrated.
Cortex; a journal devoted to the study of the nervous system and behavior, 2016
The magnitude of the hand-blink reflex (HBR), a subcortical defensive reflex elicited by the electrical stimulation of the median nerve, is increased when the stimulated hand is close to the face ('far-near effect'). This enhancement occurs through a cortico-bulbar facilitation of the polysynaptic medullary pathways subserving the reflex. Here, in two experiments, we investigated the temporal characteristics of this facilitation, and its adjustment during voluntary movement of the stimulated hand. Given that individuals navigate in a fast changing environment, one would expect the cortico-bulbar modulation of this response to adjust rapidly, and as a function of the predicted spatial position of external threats. We observed two main results. First, the HBR modulation occurs without a temporal delay between when the hand has reached the stimulation position and when the stimulus happens (Experiments 1 and 2). Second, the voluntary movement of the hand interacts with the '...
Recording the Trigemino-Facial Inhibitory Reflex: Technique and Normal Findings
Journal of Clinical Neurophysiology, 2010
The aim of this study was to propose a standardized technique for recording the trigeminofacial inhibitory reflex (TFIR) and to provide reference data of its components. The TFIR was recorded with concentric needle electrodes from the voluntarily activated depressor anguli oris muscle bilaterally in 26 healthy subjects (23-83 years). A vertical line was drawn from the corner of the mouth to the mandible margin, from which the needle insertion point was localized moving 1 to 2 cm upward and 1 to 2 cm laterally. The mentalis nerve was stimulated by surface electrodes at an intensity of 10ϫ the perceptive threshold. The recovery cycle was studied at interstimulus intervals of 200, 350, and 500 milliseconds. The TFIR was constantly elicited in all participants. Upper normal limits (mean Ϯ 3 SD) of latency of the TFIR both ipsilateral and contralateral to stimulation were 65 milliseconds. Recovery of the reflex was of 71% at 200 milliseconds, 84% at 350 milliseconds, and 98% at 500 milliseconds interstimulus intervals. The recovery at the 200 milliseconds interstimulus intervals increased significantly with participant's age. The TFIR can be consistently and reliably recorded from the depressor anguli oris muscle using a standard technique. The reflex is robust showing complete recovery at 500 milliseconds interstimulus intervals.
Neuroscience Letters, 2001
Laser stimulation of the supraorbital regions evokes brain potentials (LEPs) related to trigeminal nociception. The aim of this study was to record the R2 component of the blink re¯ex and the corneal re¯ex in 20 normal subjects, comparing the scalp activity following these re¯exes with the nociceptive potentials evoked by CO 2 laser stimulation of supraorbital regions. Cortical and muscular re¯exes evoked by stimulation of the ®rst trigeminal branch were recorded simultaneously. The R2 component of the blink re¯ex and the corneal re¯ex were followed by two cortical peaks, which resembled morphologically N-P waves of LEPs. The two peaks demonstrated a difference in latency of approximately 40 ms, which is consistent with activation time of nociception. This ®nding suggests that these re¯exes are induced by activation of small pain-related ®bers. q