Negro, Francesco

[["dc.bibliographiccitation.firstpage","1699"],["dc.bibliographiccitation.issue","5"],["dc.bibliographiccitation.journal","Journal of Neurophysiology"],["dc.bibliographiccitation.lastpage","1706"],["dc.bibliographiccitation.volume","119"],["dc.contributor.author","Yavuz, Utku Ş."],["dc.contributor.author","Negro, Francesco"],["dc.contributor.author","Diedrichs, Robin"],["dc.contributor.author","Farina, Dario"],["dc.date.accessioned","2019-02-06T11:53:32Z"],["dc.date.available","2019-02-06T11:53:32Z"],["dc.date.issued","2018"],["dc.description.abstract","Motor neurons innervating antagonist muscles receive reciprocal inhibitory afferent inputs to facilitate the joint movement in the two directions. The present study investigates the mutual transmission of reciprocal inhibitory afferent inputs between the tibialis anterior (TA) and triceps surae (soleus and medial gastrocnemius) motor units. We assessed this mutual mechanism in large populations of motor units for building a statistical distribution of the inhibition amplitudes during standardized input to the motor neuron pools to minimize the effect of modulatory pathways. Single motor unit activities were identified using high-density surface electromyography (HDsEMG) recorded from the TA, soleus (Sol), and medial gastrocnemius (GM) muscles during isometric dorsi- and plantarflexion. Reciprocal inhibition on the antagonist muscle was elicited by electrical stimulation of the tibial (TN) or common peroneal nerves (CPN). The probability density distributions of reflex strength for each muscle were estimated to examine the strength of mutual transmission of reciprocal inhibitory input. The results showed that the strength of reciprocal inhibition in the TA motor units was fourfold greater than for the GM and the Sol motor units. This suggests an asymmetric transmission of reciprocal inhibition between ankle extensor and flexor muscles. This asymmetry cannot be explained by differences in motor unit type composition between the investigated muscles since we sampled low-threshold motor units in all cases. Therefore, the differences observed for the strength of inhibition are presumably due to a differential reciprocal spindle afferent input and the relative contribution of nonreciprocal inhibitory pathways. NEW & NOTEWORTHY We investigated the mutual transmission of reciprocal inhibition in large samples of motor units using a standardized input (electrical stimulation) to the motor neurons. The results demonstrated that the disynaptic reciprocal inhibition exerted between ankle flexor and extensor muscles is asymmetric. The functional implication of asymmetric transmission may be associated with the neural strategies of postural control."],["dc.identifier.doi","10.1152/jn.00424.2017"],["dc.identifier.pmid","29384455"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/57534"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.relation.eissn","1522-1598"],["dc.title","Reciprocal inhibition between motor neurons of the tibialis anterior and triceps surae in humans"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","37"],["dc.bibliographiccitation.journal","Acta Physiologica"],["dc.bibliographiccitation.lastpage","38"],["dc.bibliographiccitation.volume","215"],["dc.contributor.author","Yavuz, Utku Suekrue"],["dc.contributor.author","Negro, Francesco"],["dc.contributor.author","Sebik, Oguz"],["dc.contributor.author","Holobar, Ales"],["dc.contributor.author","Froemmel, Cornelius"],["dc.contributor.author","Turker, Kemal S."],["dc.contributor.author","Farina, Dario"],["dc.date.accessioned","2018-11-07T09:49:23Z"],["dc.date.available","2018-11-07T09:49:23Z"],["dc.date.issued","2015"],["dc.identifier.isi","000364786400081"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/35500"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-blackwell"],["dc.publisher.place","Hoboken"],["dc.relation.issn","1748-1716"],["dc.relation.issn","1748-1708"],["dc.title","The new technique for accurate estimation of the spinal cord circuitry: recording reflex responses of large motor unit populations"],["dc.type","conference_abstract"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","4305"],["dc.bibliographiccitation.issue","19"],["dc.bibliographiccitation.journal","The Journal of Physiology"],["dc.bibliographiccitation.lastpage","4318"],["dc.bibliographiccitation.volume","593"],["dc.contributor.author","Yavuz, Utku Suekrue"],["dc.contributor.author","Negro, Francesco"],["dc.contributor.author","Sebik, Oguz"],["dc.contributor.author","Holobar, Ales"],["dc.contributor.author","Froemmel, Cornelius"],["dc.contributor.author","Turker, Kemal S."],["dc.contributor.author","Farina, Dario"],["dc.date.accessioned","2018-11-07T09:50:51Z"],["dc.date.available","2018-11-07T09:50:51Z"],["dc.date.issued","2015"],["dc.description.abstract","We propose and validate a non-invasive method that enables accurate detection of the discharge times of a relatively large number of motor units during excitatory and inhibitory reflex stimulations. High-density surface electromyography (HDsEMG) and intramuscular EMG (iEMG) were recorded from the tibialis anterior muscle during ankle dorsiflexions performed at 5%, 10% and 20% of the maximum voluntary contraction (MVC) force, in nine healthy subjects. The tibial nerve (inhibitory reflex) and the peroneal nerve (excitatory reflex) were stimulated with constant current stimuli. In total, 416 motor units were identified from the automatic decomposition of the HDsEMG. The iEMG was decomposed using a state-of-the-art decomposition tool and provided 84 motor units (average of two recording sites). The reflex responses of the detected motor units were analysed using the peri-stimulus time histogram (PSTH) and the peri-stimulus frequencygram (PSF). The reflex responses of the common motor units identified concurrently from the HDsEMG and the iEMG signals showed an average disagreement (the difference between number of observed spikes in each bin relative to the mean) of 8.2 +/- 2.2% (5% MVC), 6.8 +/- 1.0% (10% MVC) and 7.5 +/- 2.2% (20% MVC), for reflex inhibition, and 6.5 +/- 4.1%, 12.0 +/- 1.8% and 13.9 +/- 2.4%, for reflex excitation. There was no significant difference between the characteristics of the reflex responses, such as latency, amplitude and duration, for the motor units identified by both techniques. Finally, reflex responses could be identified at higher force (4 of the 9 subjects performed contraction up to 50% MVC) using HDsEMG but not iEMG, because of the difficulty in decomposing the iEMG at high forces. In conclusion, single motor unit reflex responses can be estimated accurately and non-invasively in relatively large populations of motor units using HDsEMG. This non-invasive approach may enable a more thorough investigation of the synaptic input distribution on active motor units at various force levels."],["dc.description.sponsorship","European Research Council (ERC) [267888]"],["dc.identifier.doi","10.1113/JP270635"],["dc.identifier.isi","000363090500002"],["dc.identifier.pmid","26115007"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/35792"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-blackwell"],["dc.relation.issn","1469-7793"],["dc.relation.issn","0022-3751"],["dc.title","Estimating reflex responses in large populations of motor units by decomposition of the high-density surface electromyogram"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","e92390"],["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","PLoS ONE"],["dc.bibliographiccitation.volume","9"],["dc.contributor.author","Negro, Francesco"],["dc.contributor.author","Yavuz, Utku Suekrue"],["dc.contributor.author","Farina, Dario"],["dc.date.accessioned","2018-11-07T09:42:26Z"],["dc.date.available","2018-11-07T09:42:26Z"],["dc.date.issued","2014"],["dc.description.abstract","Contractile properties of human motor units provide information on the force capacity and fatigability of muscles. The spike-triggered averaging technique (STA) is a conventional method used to estimate the twitch waveform of single motor units in vivo by averaging the joint force signal. Several limitations of this technique have been previously discussed in an empirical way, using simulated and experimental data. In this study, we provide a theoretical analysis of this technique in the frequency domain and describe its intrinsic limitations. By analyzing the analytical expression of STA, first we show that a certain degree of correlation between the motor unit activities prevents an accurate estimation of the twitch force, even from relatively long recordings. Second, we show that the quality of the twitch estimates by STA is highly related to the relative variability of the inter-spike intervals of motor unit action potentials. Interestingly, if this variability is extremely high, correct estimates could be obtained even for high discharge rates. However, for physiological inter-spike interval variability and discharge rate, the technique performs with relatively low estimation accuracy and high estimation variance. Finally, we show that the selection of the triggers that are most distant from the previous and next, which is often suggested, is not an effective way for improving STA estimates and in some cases can even be detrimental. These results show the intrinsic limitations of the STA technique and provide a theoretical framework for the design of new methods for the measurement of motor unit force twitch."],["dc.description.sponsorship","European Research Council Advanced Grant DEMOVE [267888]"],["dc.identifier.doi","10.1371/journal.pone.0092390"],["dc.identifier.isi","000333675600035"],["dc.identifier.pmid","24667744"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/10062"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/33952"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Public Library Science"],["dc.relation.issn","1932-6203"],["dc.rights","CC BY 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/4.0"],["dc.title","Limitations of the Spike-Triggered Averaging for Estimating Motor Unit Twitch Force: A Theoretical Analysis"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1041"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Journal of Neurophysiology"],["dc.bibliographiccitation.lastpage","1047"],["dc.bibliographiccitation.volume","114"],["dc.contributor.author","Yavuz, Utku Suekrue"],["dc.contributor.author","Negro, Francesco"],["dc.contributor.author","Falla, Deborah"],["dc.contributor.author","Farina, Dario"],["dc.date.accessioned","2018-11-07T09:53:43Z"],["dc.date.available","2018-11-07T09:53:43Z"],["dc.date.issued","2015"],["dc.description.abstract","It has been observed that muscle pain influences force variability and low-frequency (<3 Hz) oscillations in the neural drive to muscle. In this study, we aimed to investigate the effect of experimental muscle pain on the neural control of muscle force at higher frequency bands, associated with afferent feedback (alpha band, 5-13 Hz) and with descending cortical input (beta band, 15-30 Hz). Single-motor unit activity was recorded, in two separate experimental sessions, from the abductor digiti minimi (ADM) and tibialis anterior (TA) muscles with intramuscular wire electrodes, during isometric abductions of the fifth finger at 10% of maximal force [maximum voluntary contraction (MVC)] and ankle dorsiflexions at 25% MVC. The contractions were repeated under three conditions: no pain (baseline) and after intramuscular injection of isotonic (0.9%, control) and hypertonic (5.8%, painful) saline. The results showed an increase of the relative power of both the force signal and the neural drive at the tremor frequency band (alpha, 5-13 Hz) between the baseline and hypertonic (painful) conditions for both muscles (P < 0.05) but no effect on the beta band. Additionally, the strength of motor unit coherence was lower (P < 0.05) in the hypertonic condition in the alpha band for both muscles and in the beta band for the ADM. These results indicate that experimental muscle pain increases the amplitude of the tremor oscillations because of an increased variability of the neural control (common synaptic input) in the tremor band. Moreover, the concomitant decrease in coherence suggests an increase in independent input in the tremor band due to pain."],["dc.description.sponsorship","European Research Council Advanced Grant DEMOVE [267888]"],["dc.identifier.doi","10.1152/jn.00391.2015"],["dc.identifier.isi","000360554100026"],["dc.identifier.pmid","26019314"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/36382"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Physiological Soc"],["dc.relation.issn","1522-1598"],["dc.relation.issn","0022-3077"],["dc.title","Experimental muscle pain increases variability of neural drive to muscle and decreases motor unit coherence in tremor frequency band"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.journal","Acta Physiologica"],["dc.bibliographiccitation.volume","215"],["dc.contributor.author","Yavuz, Utku Suekrue"],["dc.contributor.author","Negro, Francesco"],["dc.contributor.author","Sebik, Oguz"],["dc.contributor.author","Froemmel, Cornelius"],["dc.contributor.author","Farina, Dario"],["dc.contributor.author","Turker, Kemal S."],["dc.date.accessioned","2018-11-07T09:49:23Z"],["dc.date.available","2018-11-07T09:49:23Z"],["dc.date.issued","2015"],["dc.format.extent","37"],["dc.identifier.isi","000364786400080"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/35501"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-blackwell"],["dc.publisher.place","Hoboken"],["dc.relation.issn","1748-1716"],["dc.relation.issn","1748-1708"],["dc.title","Discharge rate and synaptic noise affect reflex response regime of motor unit population"],["dc.type","conference_abstract"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]