Short latency afferent inhibition and facilitation in patients with writer's cramp

2004 ◽  
Vol 20 (2) ◽  
pp. 238-242 ◽  
Author(s):  
Kirn R. Kessler ◽  
Diane Ruge ◽  
Tihomir V. Ilić ◽  
Ulf Ziemann
Keyword(s):  
Short Latency ◽  
Short Latency Afferent Inhibition ◽  
Writer’S Cramp ◽  
Afferent Inhibition ◽  
Writer's Cramp

Slow rTMS to the somatosensory cortex attenuates afferent inhibition in patients with writer's cramp

2005 ◽  
Vol 32 (S 4) ◽  
Author(s):  
C Demiralay ◽  
T Bäumer ◽  
U Hidding ◽  
R Helmich ◽  
S Wunderlich ◽  
...  
Keyword(s):  
Somatosensory Cortex ◽  
Writer’S Cramp ◽  
Afferent Inhibition ◽  
Writer's Cramp

scholarly journals Short-latency afferent inhibition and somato-sensory evoked potentials during the migraine cycle: surrogate markers of a cycling cholinergic thalamo-cortical drive?

2020 ◽  
Author(s):  
Gianluca Coppola ◽  
Davide Di Lenola ◽  
Chiara Abagnale ◽  
Fabio Ferrandes ◽  
Gabriele Sebastianelli ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Evoked Potentials ◽  
Motor Evoked Potential ◽  
Short Latency ◽  
Excitatory Effect ◽  
Sensory Afferents ◽  
Short Latency Afferent Inhibition ◽  
Afferent Inhibition ◽  
Cycle Dependent ◽  
Sensory Evoked

Abstract Background: Short-latency afferent inhibition (SAI) consists of motor cortex inhibition induced by sensory afferents and depends on the excitatory effect of cholinergic thalamocortical projections on inhibitory GABAergic cortical networks. Given the electrophysiological evidence for thalamo-cortical dysrhythmia in migraine, we studied SAI in migraineurs during and between attacks and searched for correlations with somatosensory habituation, thalamocortical activation, and clinical features.Methods: SAI was obtained by conditioning the transcranial magnetic stimulation-induced motor evoked potential (MEP) with an electric stimulus on the median nerve at the wrist with random stimulus intervals corresponding to the latency of individual somatosensory evoked potentials (SSEP) N20 plus 2, 4, 6, or 8 ms. We recruited 30 migraine without aura patients, 16 between (MO), 14 during an attack (MI), and 16 healthy volunteers (HV). We calculated the slope of the linear regression between the unconditioned MEP amplitude and the 4-conditioned MEPs as a measure of SAI. We also measured SSEP amplitude habituation, and high-frequency oscillations (HFO) as an index of thalamo-cortical activation.Results: Compared to HV, SAI, SSEP habituation and early SSEP HFOs were significantly reduced in MO patients between attacks, but enhanced during an attack. There was a positive correlation between degree of SAI and amplitude of early HFOs in HV, but not in MO or MI. When the two patient groups were pooled, both the MEP SAI slope and the SSEP habituation slope correlated positively with the number of days elapsed since the last migraine attack.Conclusions: The migraine cycle-dependent variations of SAI and SSEP HFOs are further evidence that facilitatory thalamocortical activation (of GABAergic networks in the motor cortex for SAI), likely to be cholinergic, is reduced in migraine at a distance from an attack, but increased ictally.

scholarly journals Somatosensory changes associated with motor skill learning

2020 ◽  
Vol 123 (3) ◽  
pp. 1052-1062 ◽  
Author(s):  
Jasmine L. Mirdamadi ◽  
Hannah J. Block
Keyword(s):  
Motor Cortex ◽  
Motor Skill ◽  
Motor Adaptation ◽  
Short Latency ◽  
Skill Learning ◽  
Motor Skill Learning ◽  
Short Latency Afferent Inhibition ◽  
Afferent Inhibition ◽  
Speed Accuracy ◽  
Somatosensory Function

Trial-and-error motor adaptation has been linked to somatosensory plasticity and shifts in proprioception (limb position sense). The role of sensory processing in motor skill learning is less understood. Unlike adaptation, skill learning involves the acquisition of new movement patterns in the absence of perturbation, with performance limited by the speed-accuracy trade-off. We investigated somatosensory changes during motor skill learning at the behavioral and neurophysiological levels. Twenty-eight healthy young adults practiced a maze-tracing task, guiding a robotic manipulandum through an irregular two-dimensional track featuring several abrupt turns. Practice occurred on days 1 and 2. Skill was assessed before practice on day 1 and again on day 3, with learning indicated by a shift in the speed-accuracy function between these assessments. Proprioceptive function was quantified with a passive two-alternative forced-choice task. In a subset of 15 participants, we measured short-latency afferent inhibition (SAI) to index somatosensory projections to motor cortex. We found that motor practice enhanced the speed-accuracy skill function ( F4,108 = 32.15, P < 0.001) and was associated with improved proprioceptive sensitivity at retention ( t22 = 24.75, P = 0.0031). Furthermore, SAI increased after training ( F1,14 = 5.41, P = 0.036). Interestingly, individuals with larger increases in SAI, reflecting enhanced somatosensory afference to motor cortex, demonstrated larger improvements in motor skill learning. These findings suggest that SAI may be an important functional mechanism for some aspect of motor skill learning. Further research is needed to test what parameters (task complexity, practice time, etc.) are specifically linked to somatosensory function. NEW & NOTEWORTHY Somatosensory processing has been implicated in motor adaptation, where performance recovers from a perturbation such as a force field. We investigated somatosensory function during motor skill learning, where a new motor pattern is acquired in the absence of perturbation. After skill practice, we found changes in proprioception and short-latency afferent inhibition (SAI), signifying somatosensory change at both the behavioral and neurophysiological levels. SAI may be an important functional mechanism by which individuals learn motor skills.

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