On the Shift from Anticipatory Heart Rate Deceleration to Acceleratory Recovery: Revisiting the Role of Response Factors

The influence of inducing motor responses of low and high force at different times in the cardiac cycle was examined. A handgrip response was used which allowed the separation of response initiation from response completion. Based on earlier work, we expected initiation, rather than completion, to initiate poststimulus cardiac acceleration. We also thought that preparation for a high force response might alter preparatory changes of interbeat interval differently from preparation for a low force response. Fifteen college-aged male subjects performed a warned reaction time task in which a visual stimulus signalled a handgrip requiring either a high or a low force to close. NoGo trials in which an inhibit signal was presented occurred on 12% of the trials. Stimuli occurred either on the R-wave of the electrocardiogram or 300 ms later. Reaction speed was varied in different trial blocks by rewarding response times of 200 ms (+/- 50 ms), 300 ms, or 400 ms. Results based on the timing of response initiation were essentially identical to those based on the timing of response completion. High force relative to low force was associated with both earlier response initiation and earlier cardiac acceleration. Force did not alter preparatory cardiac deceleration. Force and response speed did, however, alter the level of heart rate after response occurrence. Thus, response initiation (or an earlier response process) appears to induce a cardiac acceleration whose level is influenced by the speed and force of the motor response.     

Central serotonin depletion impairs both the acquisition and performance of a symmetrically reinforced go/no-go conditional visual discrimination

The involvement of central serotonin systems in behavioural disinhibition in the rat was assessed using a symmetrically reinforced go/no-go conditional visual discrimination task. Selective central 5-HT depletion (generally averaging more than 90% in neocortex, hippocampus and striatum) was induced by intracerebroventricular administration of the neurotoxin 5,7-dihydroxytryptamine (5,7-DHT) following pretreatment with both a noradrenergic and dopaminergic re-uptake inhibitor. The lesioned animals failed to acquire the conditional visual discrimination. This deficit was due to an inability to withhold responding and thus correctly complete the no-go trials. The lesioned animals responded faster both correctly, during go trials, and incorrectly during no-go trials. Impulsive early responding during the initial 1.2 s of the stimulus presentation was also increased by 5-HT depletion. Subjects that were lesioned after stable performance of the task had been acquired showed a similar, but smaller effect. These animals displayed more accurate performance of the go trials, but poorer performance of the no-go trials. Once again, go trial response latencies were faster and early responses during the no-go trials were increased by the lesion. The results suggest that previous accounts of impulsive responding induced by 5-HT depletion fail to recognise the pervasive nature of this effect, which affects multiple behavioural indices of response disinhibition and can impede the acquisition and performance of discrimination tasks depending on their precise response requirements.     

A High-Intensity Multicomponent Agility Intervention Improves Parkinson Patients’ Clinical and Motor Symptoms

Objective

To determine the effects of a high-intensity exercise therapy using sensorimotor and visual stimuli on nondemented Parkinson disease (PD) patients’ clinical symptoms, mobility, and standing balance.

Effects of Classic Progressive Resistance Training Versus Eccentric-Enhanced Resistance Training in People With Multiple Sclerosis

Objective

To compare the effects of classic progressive resistance training (PRT) versus eccentric strength-enhanced training (EST) on the performance of functional tests and different strength manifestations in the lower limb of people with multiple sclerosis (PwMS).

Improvement of Risk Prediction After Transcatheter Aortic Valve Replacement by Combining Frailty With Conventional Risk Scores

Objectives

This study sought to evaluate whether frailty improves mortality prediction in combination with the conventional scores.

Executive functions in borderline personality disorder

Different domains of executive function such as working memory and response inhibition were investigated together with elementary cognitive processes in borderline personality disorder (BPD). Patients with BPD (N=28) were compared to nonpatient controls (NP, N=28) on eight tasks (e.g. n-back, Go/NoGo, CPT-AX). In order to separate impairments in different cognitive domains and to assess the influence of more elementary cognitive processes on executive functioning, tasks were embedded in a reaction-time-decomposition approach. BPD patients solved tasks with accuracies comparable to those of nonpatients. The only exception was the n-back task, for which working memory is required: here, error rates were higher and increased more prominently in BPD patients depending on working memory load. In most tasks, movement times were shorter for BPD patients than for nonpatients, while the quality of task-solving was comparable. The faster processing in the BPD group was observable starting with the simplest task, i.e. a simple reaction-time task. These findings suggest that domains of executive functioning are differentially affected in BPD. In contrast to load-dependent deficits in working memory, response inhibition processes were unimpaired. Faster action-related processes could be observed in BPD patients in a variety of tasks; however, these did not influence executive functioning.     

Associations Between Adherence to the Physical Activity and Exercise Program Applied in the LAST Study and Functional Recovery After Stroke

ObjectiveTo investigate the associations between participants’ adherence to a physical activity and exercise program after stroke and functional recovery 18 months after inclusion.DesignSecondary analyses of the intervention arm in the multisite randomized controlled trial Life After Stroke (LAST).SettingPrimary health care services in 3 Norwegian municipalities.ParticipantsOf the participants enrolled (N=380), 186 (48.9%) were randomized to the intervention. The study sample comprised community dwelling individuals included 3 months after stroke, with mean age of 71.7 ± 11.9 years and 82 (44.1%) women. According to the National Institutes of Health Stroke Scale, 97.3% were diagnosed as having mild (National Institutes of Health Stroke Scale<8) and 2.7% with moderate (8-16 on the National Institutes of Health Stroke Scale) stroke.InterventionMonthly coaching by physiotherapists encouraging participants to adhere to 30 minutes of daily physical activity and 45-60 minutes of weekly exercise.Main Outcome MeasuresThe primary outcome was Motor Assessment Scale (MAS). Secondary outcome measures were 6-minute walk test, Timed Up and Go (TUG), Berg Balance Scale (BBS), and the physical domains of the Stroke Impact Scale (SIS). Adherence was assessed by combining participants’ training diaries and physiotherapists’ reports.ResultsThe relationship between adherence and functional recovery was analyzed with simple and multiple linear regression models. Adjusted for age, sex, dependency, and cognition, results showed statistically significant associations between adherence and functional outcomes after 18 months, as measured by MAS, TUG, BBS, and SIS (P≤.026).ConclusionsIncreased adherence to physical activity and exercise was associated with improved functional recovery after mild to moderate stroke. This emphasizes the importance of developing adherence-enhancing interventions. Dose-response studies are recommended for future research.