A Particular Form of Muscular Inhibition in Epilepsy: The Related Epileptic Silent Period

The creation and viewing of war films was one of the elements in the process by which Britain attempted to come to terms with the horrors of the First World War. During the interwar period, war films took two main forms: those which reconstructed famous battles and melodramas set against a wartime backdrop. However, the film Blighty, directed by Adrian Brunel in 1927, took a slightly different approach, focusing not on military action but on those who stayed behind on the Home Front. As a director during the silent period, Brunel trod a stony path, operating largely on the fringes of the industry and never really getting a firm foothold in the developing studio structure. He remains well regarded for his independent productions yet also directed five features for Gainsborough at the end of the silent period. Of these film, his first, Blighty, is perhaps his most successful production within the studio system in terms of managing a compromise between his desire to maintain control while also fulfilling the studio's aims and requirement for box office success. Brunel's aversion to the war film as a genre meant that from the start of the project, he was engaged in a process of negotiation with the studio in order to preserve as far as possible what he regarded as a certain creative and moral imperative.

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Supraspinal fatigue impedes recovery from a low-intensity sustained contraction in old adults

Journal of Applied Physiology ◽

10.1152/japplphysiol.00799.2011 ◽

2012 ◽

Vol 112 (5) ◽

pp. 849-858 ◽

Cited By ~ 24

Author(s):

Tejin Yoon ◽

Bonnie Schlinder-Delap ◽

Manda L. Keller ◽

Sandra K. Hunter

Keyword(s):

Young Adults ◽

Pressor Response ◽

Motor Evoked Potential ◽

Silent Period ◽

Voluntary Activation ◽

Age Difference ◽

Task Failure ◽

Old Adults ◽

Sustained Contraction ◽

Low Intensity

This study determined the contribution of supraspinal fatigue and contractile properties to the age difference in neuromuscular fatigue during and recovery from a low-intensity sustained contraction. Cortical stimulation was used to evoke measures of voluntary activation and muscle relaxation during and after a contraction sustained at 20% of maximal voluntary contraction (MVC) until task failure with elbow flexor muscles in 14 young adults (20.9 ± 3.6 yr, 7 men) and 14 old adults (71.6 ± 5.4 yr, 7 men). Old adults exhibited a longer time to task failure than the young adults (23.8 ± 9.0 vs. 11.5 ± 3.9 min, respectively, P < 0.001). The time to failure was associated with initial peak rates of relaxation of muscle fibers and pressor response ( P < 0.05). Increments in torque (superimposed twitch; SIT) generated by transcranial magnetic stimulation (TMS) during brief MVCs, increased during the fatiguing contraction ( P < 0.001) and then decreased during recovery ( P = 0.02). The increase in the SIT was greater for the old adults than the young adults during the fatiguing contraction and recovery ( P < 0.05). Recovery of MVC torque was less for old than young adults at 10 min post-fatiguing contraction (75.1 ± 8.7 vs. 83.6 ± 7.8% of control MVC, respectively, P = 0.01) and was associated with the recovery of the SIT ( r = −0.59, r2 = 0.35, P < 0.001). Motor evoked potential (MEP) amplitude and the silent period elicited during the fatiguing contraction increased less for old adults than young adults ( P < 0.05). The greater fatigue resistance with age during a low-intensity sustained contraction was attributable to mechanisms located within the muscle. Recovery of maximal strength after the low-intensity fatiguing contraction however, was impeded more for old adults than young because of greater supraspinal fatigue. Recovery of strength could be an important variable to consider in exercise prescription of old populations.

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Cortical silent period reflects individual differences in action stopping performance

Scientific Reports ◽

10.1038/s41598-021-94494-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Mario Paci ◽

Giulio Di Cosmo ◽

Mauro Gianni Perrucci ◽

Francesca Ferri ◽

Marcello Costantini

Keyword(s):

Individual Differences ◽

Response Inhibition ◽

Primary Motor Cortex ◽

Silent Period ◽

Intracortical Inhibition ◽

Stop Signal ◽

Stop Signal Task ◽

Behavioral Differences ◽

Cortical Silent Period ◽

Stop Signal Reaction Time

AbstractInhibitory control is the ability to suppress inappropriate movements and unwanted actions, allowing to regulate impulses and responses. This ability can be measured via the Stop Signal Task, which provides a temporal index of response inhibition, namely the stop signal reaction time (SSRT). At the neural level, Transcranial Magnetic Stimulation (TMS) allows to investigate motor inhibition within the primary motor cortex (M1), such as the cortical silent period (CSP) which is an index of GABAB-mediated intracortical inhibition within M1. Although there is strong evidence that intracortical inhibition varies during action stopping, it is still not clear whether differences in the neurophysiological markers of intracortical inhibition contribute to behavioral differences in actual inhibitory capacities. Hence, here we explored the relationship between intracortical inhibition within M1 and behavioral response inhibition. GABABergic-mediated inhibition in M1 was determined by the duration of CSP, while behavioral inhibition was assessed by the SSRT. We found a significant positive correlation between CSP’s duration and SSRT, namely that individuals with greater levels of GABABergic-mediated inhibition seem to perform overall worse in inhibiting behavioral responses. These results support the assumption that individual differences in intracortical inhibition are mirrored by individual differences in action stopping abilities.

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Exteroceptive Suppression of Temporalis Muscle Activity: Findings in Headache

Cephalalgia ◽

10.1046/j.1468-2982.1993.1301011.x ◽

1993 ◽

Vol 13 (1) ◽

pp. 11-14 ◽

Cited By ~ 16

Author(s):

Thomas-Martin Wallasch ◽

Hartmut Göbel

Keyword(s):

Muscle Activity ◽

Silent Period ◽

Tension Type Headache ◽

Temporalis Muscle ◽

Pharmacological Agents ◽

Chronic Tension Type Headache ◽

Exteroceptive Suppression ◽

Headache Diagnosis ◽

Secondary Phenomenon ◽

Type Headache

Exteroceptive suppression of temporalis muscle activity was proposed by Schoenen and co-workers in 1987 as a tool in headache diagnosis and research. Their finding of a decreased or abolished second silent period (ES2) in chronic tension-type headache sufferers has been confirmed by several independent laboratories during the last five years. Temporalis silent periods have also been studied in various other types of headaches. Their modulation by neuropsychological factors and pharmacological agents has also been investigated as well as their retest reliability. The pathophysiological concept of muscle contraction in tension-type headache has been challenged by studies using temporalis silent periods. The exterocepfive suppression of temporalis muscle activity points unequivocally towards a central pathogenetic mechanism, although it remains unclear whether the abnormalities of temporalis ES2 represent the primary dysfunction or a secondary phenomenon in chronic tension-type headache.

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Intracortical and Intercortical Motor Disinhibition to Transcranial Magnetic Stimulation in Newly Diagnosed Celiac Disease Patients

Nutrients ◽

10.3390/nu13051530 ◽

2021 ◽

Vol 13 (5) ◽

pp. 1530

Author(s):

Francesco Fisicaro ◽

Giuseppe Lanza ◽

Carmela Cinzia D’Agate ◽

Raffaele Ferri ◽

Mariagiovanna Cantone ◽

...

Keyword(s):

Celiac Disease ◽

Transcranial Magnetic Stimulation ◽

Magnetic Stimulation ◽

Rating Scale ◽

De Novo ◽

Motor Evoked Potentials ◽

Silent Period ◽

Cross Sectional ◽

Transcallosal Inhibition ◽

Resting Motor Threshold

Background: Celiac disease (CD) may present or be complicated by neurological and neuropsychiatric manifestations. Transcranial magnetic stimulation (TMS) probes brain excitability non-invasively, also preclinically. We previously demonstrated an intracortical motor disinhibition and hyperfacilitation in de novo CD patients, which revert back after a long-term gluten-free diet (GFD). In this cross-sectional study, we explored the interhemispheric excitability by transcallosal inhibition, which has never been investigated in CD. Methods: A total of 15 right-handed de novo, neurologically asymptomatic, CD patients and 15 age-matched healthy controls were screened for cognitive and depressive symptoms to the Montreal Cognitive Assessment (MoCA) and the 17-item Hamilton Depression Rating Scale (HDRS), respectively. TMS consisted of resting motor threshold, amplitude, latency, and duration of the motor evoked potentials, duration and latency of the contralateral silent period (cSP). Transcallosal inhibition was evaluated as duration and latency of the ipsilateral silent period (iSP). Results: MoCA and HDRS scored significantly worse in patients. The iSP and cSP were significantly shorter in duration in patients, with a positive correlation between the MoCA and iSP. Conclusions: An intracortical and interhemispheric motor disinhibition was observed in CD, suggesting the involvement of GABA-mediated cortical and callosal circuitries. Further studies correlating clinical, TMS, and neuroimaging data are needed.

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