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Kofler M, Hallett M, Iannetti GD, Versace V, Ellrich J, Téllez MJ, Valls-Solé J. The blink reflex and its modulation - Part 1: Physiological mechanisms. Clin Neurophysiol 2024; 160:130-152. [PMID: 38102022 PMCID: PMC10978309 DOI: 10.1016/j.clinph.2023.11.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Revised: 11/11/2023] [Accepted: 11/22/2023] [Indexed: 12/17/2023]
Abstract
The blink reflex (BR) is a protective eye-closure reflex mediated by brainstem circuits. The BR is usually evoked by electrical supraorbital nerve stimulation but can be elicited by a variety of sensory modalities. It has a long history in clinical neurophysiology practice. Less is known, however, about the many ways to modulate the BR. Various neurophysiological techniques can be applied to examine different aspects of afferent and efferent BR modulation. In this line, classical conditioning, prepulse and paired-pulse stimulation, and BR elicitation by self-stimulation may serve to investigate various aspects of brainstem connectivity. The BR may be used as a tool to quantify top-down modulation based on implicit assessment of the value of blinking in a given situation, e.g., depending on changes in stimulus location and probability of occurrence. Understanding the role of non-nociceptive and nociceptive fibers in eliciting a BR is important to get insight into the underlying neural circuitry. Finally, the use of BRs and other brainstem reflexes under general anesthesia may help to advance our knowledge of the brainstem in areas not amenable in awake intact humans. This review summarizes talks held by the Brainstem Special Interest Group of the International Federation of Clinical Neurophysiology at the International Congress of Clinical Neurophysiology 2022 in Geneva, Switzerland, and provides a state-of-the-art overview of the physiology of BR modulation. Understanding the principles of BR modulation is fundamental for a valid and thoughtful clinical application (reviewed in part 2) (Gunduz et al., submitted).
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Affiliation(s)
- Markus Kofler
- Department of Neurology, Hochzirl Hospital, Zirl, Austria.
| | - Mark Hallett
- National Institute of Neurological Disorders and Stroke, NIH, USA.
| | - Gian Domenico Iannetti
- University College London, United Kingdom; Italian Institute of Technology (IIT), Rome, Italy.
| | - Viviana Versace
- Department of Neurorehabilitation, Hospital of Vipiteno (SABES-ASDAA), Teaching Hospital of the Paracelsus Medical Private University (PMU), Vipiteno-Sterzing, Italy.
| | - Jens Ellrich
- Friedrich-Alexander-University Erlangen-Nuremberg, Germany.
| | | | - Josep Valls-Solé
- IDIBAPS (Institut d'Investigació August Pi i Sunyer), University of Barcelona, Spain.
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Kofler M, Valls-Solé J, Thurner M, Pucks-Faes E, Versace V. In the spotlight: How the brainstem modulates information flow. Clin Neurophysiol 2023; 148:52-64. [PMID: 36801494 DOI: 10.1016/j.clinph.2023.01.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 01/25/2023] [Accepted: 01/29/2023] [Indexed: 02/08/2023]
Abstract
OBJECTIVE The blink reflex (BR) to supraorbital nerve (SON) stimulation is reduced by either a low-intensity prepulse stimulus to digital nerves (prepulse inhibition, PPI) or a conditioning SON stimulus (SON-1) of the same intensity as the test (SON-2) stimulus (paired-pulse paradigm). We studied how PPI affects BR excitability recovery (BRER) to paired SON stimulation. METHODS Electrical prepulses were applied to the index finger 100 ms before SON-1, which was followed by SON-2 at interstimulus intervals (ISI) of 100, 300, or 500 ms. RESULTS BRs to SON-1 showed PPI proportional to prepulse intensity, but this did not affect BRER at any ISI. PPI was observed on the BR to SON-2 only when additional prepulses were applied 100 ms before SON-2, regardless of the size of BRs to SON-1. CONCLUSIONS In BR paired-pulse paradigms, the size of the response to SON-2 is not determined by the size of the response to SON-1. PPI does not leave any trace of inhibitory activity after it is enacted. SIGNIFICANCE Our data demonstrate that BR response size to SON-2 depends on SON-1 stimulus intensity and not SON-1 response size, an observation that calls for further physiological studies and cautions against unanimous clinical applicability of BRER curves.
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Affiliation(s)
- Markus Kofler
- Department of Neurology, Hochzirl Hospital, Zirl, Austria.
| | - Josep Valls-Solé
- IDIBAPS (Institut d'Investigació August Pi i Sunyer), Barcelona, Spain.
| | | | | | - Viviana Versace
- Department of Neurorehabilitation, Hospital of Vipiteno (SABES-ASDAA), Vipiteno-Sterzing, Italy; Lehrkrankenhaus der Paracelsus Medizinischen Privatuniversität, Salzburg, Austria.
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Takeuchi N, Fujita K, Taniguchi T, Kinukawa T, Sugiyama S, Kanemoto K, Nishihara M, Inui K. Mechanisms of Short- and Long-Latency Sensory Suppression: Magnetoencephalography Study. Neuroscience 2023; 514:92-99. [PMID: 36435478 DOI: 10.1016/j.neuroscience.2022.11.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 11/13/2022] [Accepted: 11/17/2022] [Indexed: 11/24/2022]
Abstract
Prepulse inhibition (PPI) is sensory suppression whose mechanism (i.e., whether PPI originates from specific inhibitory mechanisms) remains unclear. In this study, we applied the combination of short-latency PPI and long-latency paired pulse suppression in 17 healthy subjects using magnetoencephalography to investigate the mechanisms of sensory suppression. Repeats of a 25-ms pure tone without a blank at 800 Hz and 70 dB were used for a total duration of 1600 ms. To elicit change-related cortical responses, the sound pressure of two consecutive tones in this series at 1300 ms was increased to 80 dB (Test). For the conditioning stimuli, the sound pressure was increased to 73 dB at 1250 ms (Pre 1) and 80 dB at 700 ms (Pre 2). Six stimuli were randomly presented as follows: (1) Test alone, (2) Pre 1 alone, (3) Pre 1 + Test, (4) Pre 2 + Test, (5) Pre 2 + Pre 1, and (6) Pre 2 + Pre 1 + Test. The inhibitory effects of the conditioning stimuli were evaluated using N100m/P200m components. The results showed that both Pre 1 and Pre 2 significantly suppressed the Test response. Moreover, the inhibitory effects of Pre 1 and Pre 2 were additive. However, when both prepulses were present, Pre 2 significantly suppressed the Pre 1 response, suggesting that the Pre 1 response amplitude was not a determining factor for the degree of suppression. These results suggested that the suppression originated from a specific inhibitory circuit independent of the excitatory pathway.
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Affiliation(s)
- Nobuyuki Takeuchi
- Neuropsychiatric Department, Aichi Medical University, Nagakute 480-1195, Japan; Department of Psychiatry, Okazaki City Hospital, Okazaki 444-8553, Japan.
| | - Kohei Fujita
- Neuropsychiatric Department, Aichi Medical University, Nagakute 480-1195, Japan
| | - Tomoya Taniguchi
- Department of Anesthesiology, Nagoya University, Nagoya 466-8550, Japan
| | - Tomoaki Kinukawa
- Department of Anesthesiology, Nagoya University, Nagoya 466-8550, Japan
| | - Shunsuke Sugiyama
- Department of Psychiatry and Psychotherapy, Gifu University, Gifu 501-1193, Japan
| | - Kousuke Kanemoto
- Neuropsychiatric Department, Aichi Medical University, Nagakute 480-1195, Japan
| | - Makoto Nishihara
- Neuropsychiatric Department, Aichi Medical University, Nagakute 480-1195, Japan; Multidisciplinary Pain Center, Aichi Medical University, Nagakute 480-1195, Japan
| | - Koji Inui
- Department of Functioning and Disability, Institute for Developmental Research, Aichi Developmental Disability Center, Kasugai 480-0392, Japan
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Neurophysiologic assessment of small fibre damage in chemotherapy-induced peripheral neuropathy. Clin Neurophysiol 2021; 132:1947-1956. [PMID: 34034962 DOI: 10.1016/j.clinph.2021.02.406] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 02/16/2021] [Accepted: 02/28/2021] [Indexed: 11/23/2022]
Abstract
OBJECTIVE In patients with chemotherapy-induced peripheral neuropathy (CIPN), demonstration of small fibre (SF) damage is important to understand chronic late effects. METHODS Thirty patients having complaints compatible with possible CIPN following treatment with oxaliplatin or docetaxel were compared with 27 healthy subjects. All subjects were evaluated with quantitative sensory testing (QST) assessing SF function and laser evoked potentials (LEP). In addition, SF-damage was assessed using cutaneous silent periods evoked with electrical (El-CSP) and laser (Ls-CSP) stimuli. RESULTS For LEP, N2P2 amplitudes were significantly smaller in patients than controls in both upper (P = 0.007) and lower extremities (P = 0.002), and the N1 amplitude in upper extremities of patients were significantly smaller than in controls (P = 0.001). SF-QST, LEP, Ls-CSP, and El-CSP were abnormal in 10 (33.3%), 16 (53.3%), 19 (63.3%), and 24 (80%) of CIPN patients, respectively. CONCLUSIONS In patients with possible CIPN, El-CSP and Ls-CSP were more often abnormal than LEP and QST. This is probably because El-CSP and Ls-CSP inform mainly about peripheral nociceptive fibres, while LEP and QST inform about peripheral and central nociceptive pathways together. SIGNIFICANCE LEP and QST are established methods to detect SF-damage. El- and Ls-CSP might help clinicians in diagnosing SF-damage.
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Versace V, Campostrini S, Sebastianelli L, Saltuari L, Valls-Solé J, Kofler M. Threat vs control: Potentiation of the trigeminal blink reflex by threat proximity is overruled by self-stimulation. Psychophysiology 2020; 57:e13626. [PMID: 32573801 DOI: 10.1111/psyp.13626] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 04/21/2020] [Accepted: 05/19/2020] [Indexed: 11/27/2022]
Abstract
The magnitude of the defensive blink reflex is modulated by continuous assessment of its protective value. Here, we studied whether the trigeminal blink reflex (TBR) is modulated by a potentially offensive object close to the face, and, if so, whether self-stimulation or observation of the act of stimulus triggering counteracts such modulation. In all, 26 healthy volunteers participated in various experimental conditions. At baseline, an experimenter triggered supraorbital nerve stimuli remotely, unseen by the participants; in experimental conditions, the experimenter held a stimulation probe close to the participant's face but triggered the stimuli either remotely, "surprising" participants (S1 ), or directly on the probe, observed by participants (S2 ). In other conditions, participants triggered stimuli themselves on the probe held next to their body (S3 ) or held in front of their face (S4 ). The latter condition was repeated similarly, but pressing the button only randomly generated electrical stimuli (S5, "Russian roulette"). The size of the R2 component of the TBR (TBR-R2) was the main outcome measure. Compared to baseline, TBR-R2 area was significantly larger in S1 when the "threatening" probe was close to the face and the participant had no control over stimulation. Conversely, TBR-R2 was suppressed when participants either saw the action of triggering, thus being aware (S2 ), or had full initiative over stimulation (S3 , S4 ). Random self-generated stimuli (S5 ) inhibited TBR-R2, but to a lesser extent than S3 and S4. Perceived threat close to the face facilitates TBR-R2, but knowledge about impending stimulation or self-agency overrules this effect.
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Affiliation(s)
- Viviana Versace
- Department of Neurorehabilitation, Hospital of Vipiteno/Sterzing, Vipiteno/Sterzing, Italy.,Research Unit for Neurorehabilitation of South Tyrol, Bolzano/Bozen, Italy
| | - Stefania Campostrini
- Department of Neurorehabilitation, Hospital of Vipiteno/Sterzing, Vipiteno/Sterzing, Italy.,Research Unit for Neurorehabilitation of South Tyrol, Bolzano/Bozen, Italy
| | - Luca Sebastianelli
- Department of Neurorehabilitation, Hospital of Vipiteno/Sterzing, Vipiteno/Sterzing, Italy.,Research Unit for Neurorehabilitation of South Tyrol, Bolzano/Bozen, Italy
| | - Leopold Saltuari
- Research Unit for Neurorehabilitation of South Tyrol, Bolzano/Bozen, Italy.,Department of Neurology, Hochzirl Hospital, Zirl, Austria
| | - Josep Valls-Solé
- IDIBAPS (Institut d'Investigació August Pi i Sunyer), Facultat de Medicina, University of Barcelona, Barcelona, Spain
| | - Markus Kofler
- Department of Neurology, Hochzirl Hospital, Zirl, Austria
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Blink test results in patients with central sleep apnea syndrome. Sleep Biol Rhythms 2019. [DOI: 10.1007/s41105-019-00234-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Barraza-Sandoval G, Casanova-Mollá J, Valls-Solé J. Neurophysiological assessment of painful neuropathies. Expert Rev Neurother 2014; 12:1297-309; quiz 1310. [DOI: 10.1586/ern.12.93] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Veciana M, Valls-Solé J, Rubio F, Callén A, Robles B. Laser evoked potentials and prepulse inhibition of the blink reflex in patients with Wallenberg's syndrome. Pain 2005; 117:443-449. [PMID: 16154697 DOI: 10.1016/j.pain.2005.07.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2004] [Revised: 07/08/2005] [Accepted: 07/21/2005] [Indexed: 11/17/2022]
Abstract
Spinothalamic tract lesions in patients with Wallenberg's syndrome can be demonstrated by abnormalities in the laser evoked potentials (LEPs) to stimulation of the affected side. However, before reaching the structures generating LEPs, laser stimuli can induce effects at a subcortical level. We examined LEPs and laser-induced prepulse inhibition of the blink reflex in seven patients with Wallenberg's syndrome within a month after the infarct. All patients had abnormally elevated thresholds for temperature and pain sensation, and for pinprick pain induced by laser stimuli, in the affected vs the non-affected side. LEPs to stimulation of the affected side were abnormal because of absent, reduced or delayed responses. However, the same laser stimuli that were unable to induce LEPs generated normal inhibition of the blink reflex response when applied 250ms before a trigeminal nerve electrical stimulus. The percentage inhibition induced in the R2 response of the blink reflex by laser stimulation of the affected side was not different from that induced by stimulation of the non-affected side, or in control subjects. These results are compatible with either a different pathway for prepulse inhibition and evoked potentials or a reduced energy requirement of the sensory input generating prepulse inhibition in comparison to that generating evoked potentials.
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Affiliation(s)
- Misericordia Veciana
- Neurofisiologia, Servei de Neurologia, Hospital de Sant Boi, Barcelona, Spain Unitat d'EMG, Servei de Neurologia, Hospital Clínic, Villarroel, 170, Barcelona 08036, Spain Servei de Neurologia, Hospital Universitari de Bellvitge, Hospitalet de Llobregat, Barcelona, Spain
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Trujillo-Hernández B, Huerta M, Pérez-Vargas D, Trujillo X, Vásquez C. Blink reflex alterations in recently diagnosed diabetic patients. J Clin Neurosci 2003; 10:306-9. [PMID: 12763333 DOI: 10.1016/s0967-5868(02)00306-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE The aim of the present study was to determine the frequency of blink reflex alterations and to examine the influence of hyperglycemia in inducing the alterations in recently diagnosed Type 2 diabetes mellitus patients. METHODS A cross-sectional study was carried out on patients having asymptomatic diabetes with a period of evolution under 10 years. In all 47 patients (26 women and 21 men), serum glycemia levels were determined and the latency onset of the blink reflex components were measured. RESULTS The average patient age was 44.5+/-11.0 (mean+/-SD) years with a diabetes evolution period of 4.3+/-2.9 (mean+/-SD) years. After a fasting serum glucose test, the diabetic patients were catalogued as normoglycemic (< or =126 mg/dl) or as hyperglycemic (> 26 mg/dl) and subjected to a blink reflex test. The results obtained from the diabetic patients were compared with those from a non-diabetic control group. 14.8-31.9% of the diabetic patients showed alterations in blink reflex component latencies. The differences compared with the control group were significant (p<0.05). CONCLUSIONS Diabetes, as is well-known, can affect the central and peripheral nervous system and there does not appear to be a link between glycemic levels and blink reflex components. However, blink reflex alterations were present even in diabetic patients with a relatively short period of disease evolution.
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Affiliation(s)
- Benjamin Trujillo-Hernández
- Unit of Clinical Epidemiology Research, Hospital General de Zona y Medicina Familiar No. 1, Col., Colima, Mexico.
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Cervera A, Veciana M, Valls-Solé J. Sympathetic sudomotor skin responses induced by laser stimuli in normal human subjects. Neurosci Lett 2002; 334:115-8. [PMID: 12435485 DOI: 10.1016/s0304-3940(02)01117-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Laser stimuli (LS) were used to induce sudomotor skin responses (SSRs) in ten healthy human subjects. LS were applied to the dorsum of the hand by means of a CO(2) laser stimulator at an intensity of 120% pain perception threshold. SSRs induced by LS were of longer latency than those induced by electrical stimuli. However, response amplitude and duration were similar with either stimuli. The possibility to activate the sudomotor system by means of stimulation of pain afferents might be of clinical applicability for the functional assessment of pain pathways.
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Affiliation(s)
- Alvaro Cervera
- Unitat d'EMG, Servei de Neurologia, Hospital Cli;nic, Facultad de Medicina, Universitat de Barcelona, Institut d'Investigació Biomédica August Pi i Sunyer, Villarroel, 170, Barcelona, 08036, Spain
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Romaniello A, Valls-Solé J, Iannetti GD, Truini A, Manfredi M, Cruccu G. Nociceptive quality of the laser-evoked blink reflex in humans. J Neurophysiol 2002; 87:1386-94. [PMID: 11877513 DOI: 10.1152/jn.00041.2001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Laser radiant-heat pulses selectively excite the free nerve endings in the superficial layers of the skin and activate mechano-thermal nociceptive afferents; when directed to the perioral or supraorbital skin, high-intensity laser pulses evoke a blink-like response in the orbicularis oculi muscle (the laser blink reflex, LBR). We investigated the functional properties (startle or nociceptive origin) of the LBR and sought to characterize its central pathways. Using high-intensity CO(2)-laser stimulation of the perioral or supraorbital regions and electromyographic (EMG) recordings from the orbicularis oculi muscles, we did five experiments in 20 healthy volunteers. First, to investigate whether the LBR is a startle response, we studied its habituation to expected rhythmic stimuli and to unexpected arrhythmic stimuli. To assess its possible nociceptive quality, we studied changes in the LBR and the R2 component of the electrical blink reflex after a lidocaine-induced supraorbital nerve block and after intramuscular injection of the opiate fentanyl and the opiate-antagonist naloxone. To characterize the central pathways for the LBR, we investigated the interaction between the LBR and the three components of the blink reflex (R1, R2, and R3) by delivering laser pulses to the perioral or supraorbital regions before or after electrical stimulation of the supraorbital nerve at various interstimulus intervals. Finally, to gain further information on the central LBR pathways, using two identical CO(2)-laser stimulators, we studied the LBR recovery curves with paired laser pulses delivered to adjacent forehead points at interstimulus intervals from 250 ms to 1.5 s. The LBR withstood relatively high-frequency rhythmic stimulations, and unexpected laser pulses failed to evoke larger responses. When lidocaine began to induce hypoalgesia (about 5 min after the injection), the LBR was abolished, whereas R2 was only partly suppressed 10 min after the injection. Fentanyl injection induced strong, naloxone-reversible, LBR suppression (the response decreased to 25.3% of predrug values at 10 min and to 4% at 20 min), whereas R2 remained appreciably unchanged. Whether directed to the perioral or supraorbital regions, preceding laser pulses strongly suppressed R2 and R3 though not R1. Conversely, preceding electrical stimuli to the supraorbital nerve suppressed the LBR. In response to paired stimuli, the LBR recovered significantly faster than R2. These findings indicate that the LBR is a nociceptive reflex, which shares part of the interneuron chain mediating the nonnociceptive R2 blink reflex, probably in the medullary reticular formation. The LBR may prove useful for studying the pathophysiology of orofacial pain syndromes.
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Affiliation(s)
- A Romaniello
- Department of Neurological Sciences, University of Rome La Sapienza, Viale Universitá 30, I-00185 Rome, Italy
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