Symposia Sessions

Symposia:

The ISEK Congress will include a series of Symposia sessions which will be scheduled throughout the conference from July 12-14, 2020.  Please see the various descriptions below.

The exact day and time of each symposia will be available soon.

Estimating synaptic potentials in human motoneurons

Presenters: Kemal Turker, Koc University; Mustafa Ozyurt, University College London; Sukru Yavuz, University of Twente; Betilay Topkara, Koc University

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Properties of synaptic potentials on human motoneurons can only be estimated using indirect methods. These methods involve delivering a stimulus to activate the nervous system and recording stimulus-evoked responses using electrodes on or in skeletal muscles. Classically stimulus-evoked responses of human muscles are analyzed using surface EMG and peristimulus time histogram of single motor units. Using regularly discharging motor neurons in brain slices we have shown that these earlier methods make dramatic errors in estimating neuronal networks. We have developed and tested a novel method (peristimulus frequencygram) that overcomes entrenched errors in the classical analysis methods (reviewed in Türker and Power 2005; Trends in Neuroscience). This symposium will compare and contrast classical and novel methods for estimating synaptic potentials in a number of human studies. Human synaptic potential studies and claims made in these studies include: 1. Transcranial magnetic brain stimulation generates no cortical silent period but a single long lasting excitatory postsynaptic potential in human motor units (Ozyurt et al. 2019 PlosOne, accepted); 2. Renshaw circuitry generates a much longer lasting inhibitory postsynaptic potential than previously thought for (Ozyurt et al., 2019 Journal of Physiology); 3. Human stretch reflex generates not three but only two excitatory postsynaptic potentials in human soleus muscle (Yavuz et al, 2014 and 2016 Journal of Neurophysiology); 4. Cutaneous silent period last much longer than previously thought for (Kahya et al., 2010 Experimental Brain Research and 2016 Electromyography and Kinesiology)

Novel evidence for the assessment of neuromuscular adaptations from surface electromyography

Presenters: Taian Vieira, Politecnico di Torino; Kohei Watanabe, Chukyo University; Alessio Gallina, University of Birmingham; Hélio V Cabral, Universidade Federal do Rio de Janeiro; Yu-ichi Noto, Kyoto Prefectural University of Medicine

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This topic will focus on innovative results showing how pain, muscle damage and ageing may affect EMG descriptors. Limitations in assessing EMG descriptors will be presented. The audience will be invited to address relevant questions in real time.

Neural mechanisms of cross-education: Have the 100-year old clinical promises been fulfilled?

Presenters: Tibor Hortobágyi, University Medical Center Groningen, University of Groningen; Ken Nosaka, Edith Cowan University; Kimitaka Nakazawa, The University of Tokyo; Jonathan Farthing, University of Saskatchewan

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Unilateral motor practice improves motor performance not only in the practice limb but, curiously, also in the opposite limb that did not perform any practice. Under certain conditions, the magnitude of such cross-education or inter-limb transfer can reach 20% and clinical significance. The mechanisms of cross-education are not fully understood. A peculiar phenomenon overlooked for some 100 years but now correcting textbooks is that the activation of the brain during unilateral muscle contraction is actually not really confined to structures in the contralateral hemisphere. Instead, when healthy humans contract muscles in one arm or leg, there is a concurrent activation of the homologous muscle pair in the resting limb and brain areas in the hemisphere ispilateral to the contracting muscles. An understanding of the reasons and need for such ipsilateral activation is a contentious and highly relevant issue for conceptual and clinical reasons. Examining the brain ipsilateral activation using magnetic brain stimulation paradigms, EEG, MRI, and MEG would help us to better understand hemispheric specialization of willed and unwilled motor acts. We could then exploit this improved understanding of ipsilateral brain activation for developing treatment options for patients with unilateral neurological or orthopedic conditions. Indeed, there is some preliminary evidence for the efficacy of this rehabilitation modality in patients with an acute or chronic stroke and in patients for reducing weakness after a wrist fracture or anterior cruciate ligament surgery.

Eccentric vs Concentric Contractions: Basics and Applications

Presenters: Ken Nosaka, Edith Cowan University; Janet Taylor, Edith Cowan University; Yasuo Kawakami, Waseda University; Kazunori Nosaka, Edith Cowan University

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Distinct characteristics exist between lengthening and shortening of activated muscles. This symposium will discuss how eccentric and concentric contractions are different in the central and peripheral levels, and how muscles respond differently to them.

International Motoneuron Society: from motoneuron activity to motor control

Presenters: Francesco Negro, Universita’ degli Studi di Brescia; Charles J Heckman, Northwestern University Feinberg School of Medicine; Christopher K Thompson, Temple University; Utku Yavuz, University of Twente; Allison Hyngstrom, Marquette University

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This symposium will show recent improvements in the analysis of motor unit discharge patterns for the decoding and interpretation of the synaptic organization of motor commands. All invited speakers will be members of the International Motoneuron Society.

Neuromuscular adaptation to pain during movement

Presenters: Jean-Sebastien Roy, Université Laval; Hugo Massé-Alarie, Université Laval; Michael Hunt, University of British Columbia; Natalie Collins, University of Queensland; Kylie Tucker, University of Queensland

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Movement control relies on central processing of sensory information and selection of appropriate motor strategies; both can be impacted by pain. This symposium aims at debating how pain can perturb movement from biomechanical and neural perspectives.

Tools to examine neuromuscular adaptation to muscle fatigue during movement execution

Presenters: Laurent Bouyer, Université Laval; Jayne Garland, Western University; Jean-Sebastien Roy, Université Laval; Mathieu Bielmann, Université Laval

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As muscle fatigue develops, the neuromuscular system compensates for the loss of force before signs of fatigue become apparent. This symposium presents how early indicators of muscle fatigue can be detected during movement for future use in injury prevention.