The effect of short-term resistance training on hand reaction time improvement is independent of sexual dimorphism

Objectiveː The aim was to evaluate the effects of four weeks of resistance training and sexual dimorphism on Manual reaction time in apparently healthy subjects. Methods: The subjects of the sample were randomly allocated in two groups, as follow: Control (CTRL) - kept 4 weeks without any systematized physical activity (Nmales= 8, age= 24±3 yrs., body weight= 76.9±15.4 kg; Nfemales= 8, age= 22.5±4 yrs., body weight= 70.8±17.5 kg); Experimental (EXP) - 4 weeks of resistance training (Nmales= 8, age= 23±3 yrs., weight= 69.6±11 kg; Nfemales= 8, age= 22.5±1 yrs., body weight= 59.77±6.8 kg). The resistance training consisted of 4 exercises for upper limbs (3 sets x 8-12 reps) and 4 exercises for lower (3 sets x 12-15 reps). Manual reaction time was evaluated in a manufactured Arduino-based reaction time device connected to a computer. Results: For men, there was a significant decrease in Manual reaction time after resistance training within EXP (p<0.0001) and between groups (p<0.0001). Women showed the same results within EXP (p<0.0001) and between groups (p<0.0001). Additionally, there was no sexual dimorphism before or after four weeks of resistance training. Conclusion: The results suggest that just four weeks of resistance training was sufficient to improve Manual reaction time, regardless of sexual dimorphism. Therefore, resistance training inclusion in the training periodization seems essential to improve or rehabilitate the fast voluntary motor response, especially for activities or sports that require it.

Children who stutter exchange linguistic accuracy for processing speed in sentence comprehension

ABSTRACTComprehension of predicates and reflexives was examined in children who stutter (CWS) and children who do not stutter (CWNS) who were between 9 years, 7 months and 10 years, 2 months. Demands on working memory and manual reaction time were also assessed in two experiments that employed a four-choice picture-selection sentence comprehension task. CWS were less accurate than CWNS on the attachment of predicates. For reflexives, there was no between-group difference in accuracy, but there was a difference in speed. The two constructions induced processing at different points on a speed–accuracy continuum with CWS sacrificing accuracy to respond fast with predicates, while they maintained accuracy of reflexives by responding slower relative to CWNS. Predicates made more demands on language than nonspeech motor reaction time, whereas the reverse was the case with reflexives for CWS compared to CWNS.

Hemispheric Asymmetry in the Remapping and Maintenance of Visual Saliency Maps: A TMS Study

Parietal cortex has been implicated in the updating, after eye movements, of a salience map that is required for coherent visual experience and for the control of visually guided behavior. The current experiment investigated whether TMS over anterior intraparietal cortex (AIPCx), just after a saccade, would affect the ability to update and maintain a salience map. In order to generate a salience map, we employed a paradigm in which an uninformative cue was presented at one object in a display to generate inhibition of return (IOR)—an inhibitory tag that renders the cued object less salient than others in the display, and that slows subsequent responses to visual transients at its location. Following the cue, participants made a saccade to either left or right, and we then probed for updating of the location of IOR by measuring manual reaction time to targets appearing at cued location of the cued compared to an uncued object. Between the time of saccade initiation and target appearance, dual-pulse TMS was targeted over right (Experiment 1) or left AIPCx (Experiment 2), and a vertex control side. Updating of the location of IOR was eliminated by TMS over right, but not the left, AIPCx, suggesting that right parietal cortex is involved in the remapping of IOR. Remapping was eliminated by right AIPCx, regardless of whether the saccade was made to the left (contralateral), or right (ipsilateral) visual field, and regardless of which field the target appeared in. We conclude that right AIPCx is the neural substrate for maintaining a salience map across saccades, and not simply for propagating an efference copy of saccade commands.