Action Preparation: an integrated Perspective of Choice and Motor Control

Adaptive sensorimotor interaction requires fine movement preparation (Gallivan, Chapman, Wolpert, & Flanagan, 2018). By applying transcranial magnetic stimulation (TMS) over the primary motor cortex (M1) to elicit motor evoked potentials (MEPs) in muscles of the contralateral hand (Bestmann & Duque, 2016), many studies have shown that action preparation is associated with a transient decrease in the excitability of the corticospinal pathway; this phenomenon has been referred to as preparatory inhibition (Duque, Greenhouse, Labruna, & Ivry, 2017). Intriguingly, while a growing number of studies support the extreme robustness of this effect, the role of such preparatory inhibition remains fundamentally unclear. Our long-term goal is to test the hypothesis that preparatory inhibition reflects the operation of processes that assist action preparation at the level of both choice and motor control. In the context of choice, preparatory inhibition would serve to regulate a speed-accuracy tradeoff (SAT), with more inhibition favoring accuracy over speed. Furthermore, in the context of motor control, preparatory inhibition would facilitate the fine-tuning of muscle activity, with stronger inhibition increasing the gain of motor commands. To test these hypotheses, we recently developed a new experimental task that combines the Tokens Task (Thura & Cisek, 2014, 2017) and some features of the Pac-Man video-game (https://fr.wikipedia.org/wiki/Pac-Man). In brief, at each trial of this task, called the “Tok-Man” Task, tokens jump one-by-one from a central circle to one of two lateral circles. Subjects must then foresee which of both circles will receive more tokens by the end of the trial, and report it by pressing a button on a keyboard with their left or right index finger. Subjects may respond whenever they feel confident to make a choice, but necessarily before the last token jump. Once their choice is made, the motor control part of the trial initiates, by showing a Pac-Man on the screen. Subjects have to perform tapping movements with the chosen index finger to move the Pac-Man towards the chosen circle, while grabbing additional tokens on its way. In summary, the SAT in this task is manipulated by requiring subjects to make either fast or slow (accurate) choices, while motor tuning requirements are manipulated by requiring subjects to prepare faster or slower tapping movements. Importantly, these requirements are manipulated independently of each other, thus crossing choice and motor control instructions in four different block types. The goal here is to report preliminary behavioral data acquired on healthy subjects with this new Tok-Man Task (n=10). Our data indicates that participants adjusted their SAT according to the choice instruction: when the emphasis was on decision speed over accuracy, subjects made faster and less accurate choices. Moreover, subjects were able to change the speed of their tapping movements according to the motor control instruction, and were able to do so regardless of the SAT requirement. Hence, participants were globally able to follow choice and motor control instructions separately

Core Outcome Set-STAndardised Protocol Items: the COS-STAP Statement

Abstract Background Several hundred core outcome set (COS) projects have been systematically identified to date which, if adopted, ensure that researchers measure and report those outcomes that are most likely to be relevant to users of their research. The uptake of a COS by COS users will depend in part on the transparency and robustness of the methods used in the COS development study, which would be increased by the use of a standardised protocol. This article describes the development of the COS-STAP (Core Outcome Set-STAndardised Protocol Items) Statement for the content of a COS development study protocol. Methods The COS-STAP Statement was developed following the Enhancing the Quality and Transparency Of Health Research (EQUATOR) Network’s methodological framework for guideline development. This included an initial item generation stage, a two-round Delphi survey involving more than 150 participants representing three stakeholder groups (COS developers, journal editors and patient and public involvement researchers interested in COS development), followed by a consensus meeting with eight voting participants. Results The COS-STAP Statement consists of a checklist of 13 items considered essential documentation in a protocol, outlining the scope of the COS, stakeholder involvement, COS development plans and consensus processes. Conclusions Journal editors and peer reviewers can use the guidance to assess the completeness of a COS development study protocol submitted for publication. By providing guidance for key content, the COS-STAP Statement will enhance the drafting of high-quality protocols and determine how the COS development study will be carried out

Implications of hybridisation and cytotypic differentiation in speciation assessed by AFLP and plastid haplotypes - a case study of Potentilla alpicola La Soie

Background: Hybridisation is presumed to be an important mechanism in plant speciation and a creative evolutionary force often accompanied by polyploidisation and in some cases by apomixis. The Potentilla collina group constitutes a particularly suitable model system to study these phenomena as it is morphologically extensively variable, exclusively polyploid and expresses apomixis. In the present study, the alpine taxon Potentilla alpicola has been chosen in order to study its presumed hybrid origin, identify underlying evolutionary processes and infer the discreteness or taxonomic value of hybrid forms. Results: Combined analysis of AFLP, cpDNA sequences and ploidy level variation revealed a hybrid origin of the P. alpicola populations from South Tyrol (Italy) resulting from crosses between P. pusilla and two cytotypes of P. argentea. Hybrids were locally sympatric with at least one of the parental forms. Three lineages of different evolutionary origin comprising two ploidy levels were identified within P. alpicola. The lineages differed in parentage and the complexity of the evolutionary process. A geographically wide-spread lineage thus contrasted with locally distributed lineages of different origins. Populations of P. collina studied in addition, have been regarded rather as recent derivatives of the hexaploid P. argentea. The observation of clones within both P. alpicola and P. collina suggested a possible apomictic mode of reproduction. Conclusions: Different hybridisation scenarios taking place on geographically small scales resulted in viable progeny presumably stabilised by apomixis. The case study of P. alpicola supports that these processes played a significant role in the creation of polymorphism in the genus Potentilla. However, multiple origin of hybrids and backcrossing are considered to produce a variety of evolutionary spontaneous forms existing aside of reproductively stabilised, established lineages

Effect of Usnic Acid on Candida orthopsilosis and C. parapsilosis

The activity of usnic acid against Candida orthopsilosis and Candida parapsilosis on planktonic and biofilm conditions was investigated by using a broth microdilution and microplate methods. Potent in vitro activities against different Candida species were obtained. The metabolic activity of sessile cells of C. parapsilosis complex was reduced by 80% at four times the 80% inhibitory concentration. The in vitro studies support further efforts to determine whether usnic acid can be used clinically to cure patients with Candida infections