Excitability tests using high-density surface-EMG: A novel approach to studying single motor units

Publication date: August 2018
Source:Clinical Neurophysiology, Volume 129, Issue 8
Author(s): Boudewijn T.H.M. Sleutjes, Judith Drenthen, Ernest Boskovic, Leonard J. van Schelven, Maria O. Kovalchuk, Paul G.E. Lumens, Leonard H. van den Berg, Hessel Franssen
ObjectiveTo study excitability of single motor units (MUs) using high-density surface-EMG.MethodsMotor unit action potentials (MUAPs) were evoked by submaximal stimulation of the median nerve at the wrist and recorded with a 9 × 14 electrode grid on the skin overlying the thenar muscles. For excitability tests of single MUs, the most optimal specific single-channel surface-EMG signal was selected based on the spatiotemporal profile of single MUs.ResultsAxonal excitability measures were successfully obtained from 14 single MUs derived from ten healthy subjects. Selecting the optimal single-channel surface-EMG signals minimized interference from other single MUs and improved signal-to-noise ratio. The muscle fiber conduction velocity (MFCV) could also be derived from the unique spatiotemporal profile of single MUs.ConclusionHigh-density surface-EMG helps to isolate single MUAP responses, making it a suitable technique for assessing excitability in multiple single motor axons per nerve.SignificanceOur method enables the reliable study of ion-channel dysfunction in single motor axons of nerves without any requirement for specific conditions, such as prominent MU loss or enlarged MUAPs due to collateral sprouting.



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Periodic component analysis as a spatial filter for SSVEP-based brain-computer interface

Publication date: Available online 15 June 2018
Source:Journal of Neuroscience Methods
Author(s): G R Kiran Kumar, M Ramasubba Reddy
BackgroundTraditional Spatial filters used for steady-state visual evoked potential (SSVEP) extraction such as minimum energy combination (MEC) require the estimation of the background electroencephalogram (EEG) noise components. Even though this leads to improved performance in low signal to noise ratio (SNR) conditions, it makes such algorithms slow compared to the standard detection methods like canonical correlation analysis (CCA) due to the additional computational cost.New methodIn this paper, Periodic component analysis (πCA) is presented as an alternative spatial filtering approach to extract the SSVEP component effectively without involving extensive modelling of the noise. The πCA can separate out components corresponding to a given frequency of interest from the background electroencephalogram (EEG) by capturing the temporal information and does not generalize SSVEP based on rigid templates.ResultsData from ten test subjects were used to evaluate the proposed method and the results demonstrate that the periodic component analysis acts as a reliable spatial filter for SSVEP extraction. Statistical tests were performed to validate the results.Comparison with existing methodsThe experimental results show that πCA provides significant improvement in accuracy compared to standard CCA and MEC in low SNR conditions.ConclusionsThe results demonstrate that πCA provides better detection accuracy compared to CCA and on par with that of MEC at a lower computational cost. Hence πCA is a reliable and efficient alternative detection algorithm for SSVEP based brain-computer interface (BCI).



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Food deprivation reduces the susceptibility to size-contrast illusions

Publication date: 1 September 2018
Source:Appetite, Volume 128
Author(s): Noa Zitron-Emanuel, Tzvi Ganel
Hunger, caused by mild amount of food deprivation, is an everyday physiological state familiar to us all. Ongoing research has pinpointed the way hunger affects people's physiological functions as well as their attitudes and allocation of attention toward domain-specific, food-related objects. Yet, little is known about the way food deprivation affects basic perceptual abilities. Here, we utilized size-contrast visual illusions commonly associated with food to explore the way deprivation affects relative processing of food size. In two experiments (Nexp1 = 32 females, mean age: 24.31; Nexpt2 = 41 females, 40 males, mean age: 23.84), we examined the effect food deprivation has on participants' susceptibility to the Delboeuf illusion, which biases the perceived size of a neutral or of a food-related object when it is placed within the context of another object (e.g., a pizza is perceived as smaller when placed on a larger plate or tray). The results showed that food deprivation reduces the illusory bias for food-related but not for neutral stimuli. Such reduction in the illusory effect indicates reliance on analytic, rather than on relative processing style, for domain-specific stimuli when in the state of hunger.



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In adolescence a higher ‘eveningness in energy intake’ is associated with higher total daily energy intake

Publication date: 1 September 2018
Source:Appetite, Volume 128
Author(s): Tanja Diederichs, Ines Perrar, Sarah Roßbach, Ute Alexy, Anette E. Buyken
The present manuscript addressed two hypotheses: (i) As children age, energy intake is shifted from morning (energy intake <11am) to evening hours (energy intake >6pm) (ii) A higher 'eveningness in energy intake' (i.e. evening minus morning energy intake) is associated with a higher total daily energy intake. Data were analyzed from 262 DONALD cohort study participants, who had completed at least one 3-day weighed dietary record in the age groups 3/4, 5/6, 7/8, 9/10, 11/12, 13/14, 15/16 and 17/18 years (y). 'Eveningness in energy intake' was compared across age groups and related to total daily energy intake for each age group (multiple cross-sectional analyses). 'Eveningness' increased progressively from age group 3/4y to age group 17/18y. A median surplus of evening energy intake (i.e. when evening intake exceeded morning intake) was firstly observed for age group 11/12y. From age group 11/12y onwards, a higher 'eveningness' was associated with a higher total daily energy intake (all p < 0.04). Difference in total daily energy intake between the highest and the lowest tertile of 'eveningness' was largest for age group 17/18y, amounting to an 11% higher intake among adolescents in the highest as compared to those in the lowest tertile. In conclusion, energy intake progressively shifts from morning to evening hours as children age. Once evening energy intake exceeds morning energy intake, a higher 'eveningness in energy intake' is associated with higher total daily energy intake.



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Disordered eating in college sorority women: A social network analysis of a subset of members from a single sorority chapter

Publication date: 1 September 2018
Source:Appetite, Volume 128
Author(s): Kendra R. Becker, Monika M. Stojek, Allan Clifton, Joshua D. Miller
ObjectiveDisordered eating attitudes and behaviors are prevalent among college women, and peers appear to influence current and future eating pathology. Social network analysis (SNA) is an innovative quantitative method to examine relationships (i.e., ties) among people based on their various attributes. In this study, the social network of one sorority was modeled using exponential random graph model (ERGM) to explore if homophily, or the tendency for relationship ties to exist based on shared attributes, was present according to sorority members' disordered eating behaviors/attitudes and their body mass index (BMI).MethodParticipants included members of one sorority at a large Southeastern university. All members were included on a roster unless they elected to opt out during the consent process, and 41 (19%) of the members completed the study measures. Participants completed the Social Network Questionnaire developed for this study (degree of "liking" of every member on the roster), the Eating Disorder Examination-Questionnaire (EDE-Q), and a demographics questionnaire in exchange for one hour of community service credit.ResultsThe final sample consisted of mostly White women with an average age of 20. Homophily across liking ties was examined based on the EDE-Q Global scale, episodes of binge eating, and BMI. The greater the difference in EDE-Q Global scores, the more likely the participants were to like one another. The greater the difference in BMI, the less likely the participants were to like one another. Binge eating was unrelated to homophily.DiscussionCollege sorority women appear to prefer other women with dissimilar levels of disordered eating attitudes, suggesting complex interactions between stigmatized or valued disordered eating attributes. Women with similar BMI were more likely to like one another, confirming past findings.



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The Science of Science Communication III: Inspiring Novel Collaborations and Building Capacity: Proceedings of a Colloquium.

Successful scientists must be effective communicators within their professions. Without those skills, they could not write papers and funding proposals, give talks and field questions, or teach classes and mentor students. However, communicating with audiences outside their profession - people who may not share scientists' interests, technical background, cultural assumptions, and modes of expression - presents different challenges and requires additional skills. Communication about science in political or social settings differs from discourse within a scientific discipline. Not only are scientists just one of many stakeholders vying for access to the public agenda, but the political debates surrounding science and its applications may sometimes confront scientists with unfamiliar and uncomfortable discussions involving religious values, partisan interests, and even the trustworthiness of science.

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Alternative tumour necrosis factor inhibitors (TNFi) or abatacept or rituximab following failure of initial TNFi in rheumatoid arthritis: the SWITCH RCT.

This 3-arm trial in rheumatoid arthritis stopped early because of contractual issues and commissioning challenges, but 122 randomised participants were followed up, generating evidence for future meta-analyses.

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