Hand Motor Asymmetry in Task Oriented Movement

Human Physiology - Cortical asymmetry is one of the fundamental but not fully understood feature of the brain. Special attention in modern research is paid to manual asymmetry, studied using...     

Why Movement Is Captured by Music,but Less by Speech: Role of Temporal Regularity

Music has a pervasive tendency to rhythmically engage our body. In contrast, synchronization with speech is rare. Music’s superiority over speech in driving movement probably results from isochrony of musical beats, as opposed to irregular speech stresses. Moreover, the presence of regular patterns of embedded periodicities (i.e., meter) may be critical in making music particularly conducive to movement. We investigated these possibilities by asking participants to synchronize with isochronous auditory stimuli (target), while music and speech distractors were presented at one of various phase relationships with respect to the target. In Exp. 1, familiar musical excerpts and fragments of children poetry were used as distractors. The stimuli were manipulated in terms of beat/stress isochrony and average pitch to achieve maximum comparability. In Exp. 2, the distractors were well-known songs performed with lyrics, on a reiterated syllable, and spoken lyrics, all having the same meter. Music perturbed synchronization with the target stimuli more than speech fragments. However, music superiority over speech disappeared when distractors shared isochrony and the same meter. Music’s peculiar and regular temporal structure is likely to be the main factor fostering tight coupling between sound and movement.     

Abnormal Movement Preparation in Task-Specific Focal Hand Dystonia

Electrophysiological and behavioral studies in primary dystonia suggest abnormalities during movement preparation, but this crucial phase preceding movement onset has not yet been studied specifically with functional magnetic resonance imaging (fMRI). To identify abnormalities in brain activation during movement preparation, we used event-related fMRI to analyze behaviorally unimpaired sequential finger movements in 18 patients with task-specific focal hand dystonia (FHD) and 18 healthy subjects. Patients and controls executed self-initiated or externally cued prelearnt four-digit sequential movements using either right or left hands. In FHD patients, motor performance of the sequential finger task was not associated with task-related dystonic posturing and their activation levels during motor execution were highly comparable with controls. On the other hand reduced activation was observed during movement preparation in the FHD patients in left premotor cortex / precentral gyrus for all conditions, and for self-initiation additionally in supplementary motor area, left mid-insula and anterior putamen, independent of effector side. Findings argue for abnormalities of early stages of motor control in FHD, manifesting during movement preparation. Since deficits map to regions involved in the coding of motor programs, we propose that task-specific dystonia is characterized by abnormalities during recruitment of motor programs: these do not manifest at the behavioral level during simple automated movements, however, errors in motor programs of complex movements established by extensive practice (a core feature of FHD), trigger the inappropriate movement patterns observed in task-specific dystonia.     

Differences in the Head Movement During Baseball Batting between Skilled Players and Novices

ABSTRACT: Nakata, H, Miura, A, Yoshie, M, and Kudo, K. Differences in the head movement during baseball batting between skilled players and novices. J Strength Cond Res 26(10): 2632-2640, 2012-We investigated the pattern of head movement during baseball batting in 8 skilled players and 9 unskilled novices, using a high-speed video camera. The 2 directions of head movement were analyzed as an X-axis (from the home plate to the pitcher's plate) and Z-axis (vertical downward). On the X-axis, peak latency, peak value, the distance from the peak to the value at bat-ball impact, and data variability were compared between the 2 groups. On the Z-axis, peak latency, downward distance, and data variability were analyzed. Peak latency on the X-axis occurred significantly earlier in baseball players than in novices (p < 0.001), and the difference between the minimum peak and impact was significantly larger in the players (p < 0.05). The variability in peak latency on the X-axis was significantly larger in the novices (p < 0.05). The variability in peak value on the Z-axis was also significantly larger in the novices (p < 0.05). Our findings showed that the significant differences in head movement between the 2 groups should help baseball players, beginners, coaches, and strength and conditioning professionals to improve performance, be effectively applied to actual practice, and enhance coaching for batting.     

Efficiency Benefits of Live Fluoroscopy in Hand Clinics

BackgroundPostoperative imaging protocols for common hand procedures typically consist of 2-3 plain radiographs at defined intervals dependent on the surgery. Radiographs typically verify reduction, hardware position, and/or evaluate for complications, but also generate costs and alterations in clinic flow. We hypothesize the use of mini-fluoroscopic images will provide comparable clinical data with less cost and improved clinic flow. The objectives of the study were to determine if clinic-based fluoroscopic imaging is feasible for post-operative hand patients and if fluoroscopic imaging results in improved clinic flow (less waiting and more time with provider) and theoretical cost savings using mini-fluoroscopy instead of traditional radiographs.MethodsWith institutional review board exemption, the prospective use of mini-fluoroscopic evaluation of post-operative hand surgery patients was compared to traditional radiographs using time-based cohort analysis. Patients who underwent percutaneous pinning of phalanges/metacarpals, ORIF (open reduction and internal fixation) of phalanges/metacarpals or ORIF of distal radius fractures were included to evaluate common hand surgery patients. Each cohort consisted of a 3-month data collection period with prospective measures of clinic flow (wait times, appointment times, time with provider) and estimated cost compared between the groups.Results24 patients met inclusion criteria for data analysis; 11 patients in the mini-fluoroscopy group and 13 patients in the traditional radiograph group. Appointments using mini-fluoroscopy were 24 minutes shorter (53 vs 77 minutes) from patient check-in to check out time. Check-in time to rooming was 10 minutes quicker (9 vs. 19 minutes) using mini-fluoroscopy. Traditional hand radiographs have a face-value of $734 per appointment/series for a total theoretical savings of $9540 (n=13).ConclusionThe use of mini-fluoroscopy during orthopedic hand surgery post-operative visits provides a feasible, quick, cost effective way to evaluate patients postoperatively, ultimately, resulting in quicker patient appointments and greater time spent with providers. Level of Evidence: III     

The Structure of Skilled Forelimb Reaching in the Rat: A Movement Rating Scale

Skilled reaching for food is an evolutionary ancient act and is displayed by many animal species, including those in the sister clades of rodents and primates. The video describes a test situation that allows filming of repeated acts of reaching for food by the rat that has been mildly food deprived. A rat is trained to reach through a slot in a holding box for food pellet that it grasps and then places in its mouth for eating. Reaching is accomplished in the main by proximally driven movements of the limb but distal limb movements are used for pronating the paw, grasping the food, and releasing the food into the mouth. Each reach is divided into at least 10 movements of the forelimb and the reaching act is facilitated by postural adjustments. Each of the movements is described and examples of the movements are given from a number of viewing perspectives. By rating each movement element on a 3-point scale, the reach can be quantified. A number of studies have demonstrated that the movement elements are altered by motor system damage, including damage to the motor cortex, basal ganglia, brainstem, and spinal cord. The movements are also altered in neurological conditions that can be modeled in the rat, including Parkinson''s disease and Huntington''s disease. Thus, the rating scale is useful for quantifying motor impairments and the effectiveness of neural restoration and rehabilitation. Because the reaching act for the rat is very similar to that displayed by humans and nonhuman primates, the scale can be used for comparative purposes. from a number of viewing perspectives. By rating each movement element on a 3-point scale, the reach can be quantified. A number of studies have demonstrated that the movement elements are altered by motor system damage, including damage to the motor cortex, basal ganglia, brainstem, and spinal cord. The movements are also altered in neurological conditions that can be modeled in the rat, including Parkinson''s disease and Huntington''s disease. Thus, the rating scale is useful for quantifying motor impairments and the effectiveness of neural restoration and rehabilitation.Experiments on animals were performed in accordance with the guidelines and regulations set forth by the University of Lethbridge Animal Care Committee in accordance with the regulations of the Canadian Council on Animal Care.Download video file.^{(127M, mp4)}     

Encouraging Spontaneous Synchronisation with D-Jogger,an Adaptive Music Player That Aligns Movement and Music

In this study we explore how music can entrain human walkers to synchronise to the musical beat without being instructed to do so. For this, we use an interactive music player, called D-Jogger, that senses the user''s walking tempo and phase. D-Jogger aligns the music by manipulating the timing difference between beats and footfalls. Experiments are reported that led to the development and optimisation of four alignment strategies. The first strategy matched the music''s tempo continuously to the runner''s pace. The second strategy matched the music''s tempo at the beginning of a song to the runner''s pace, keeping the tempo constant for the remainder of the song. The third alignment starts a song in perfect phase synchrony and continues to adjust the tempo to match the runner''s pace. The fourth and last strategy additionally adjusts the phase of the music so each beat matches a footfall. The first two strategies resulted in a minor increase of steps in phase synchrony with the main beat when compared to a random playlist, the last two strategies resulted in a strong increase in synchronised steps. These results may be explained in terms of phase-error correction mechanisms and motor prediction schemes. Finding the phase-lock is difficult due to fluctuations in the interaction, whereas strategies that automatically align the phase between movement and music solve the problem of finding the phase-locking. Moreover, the data show that once the phase-lock is found, alignment can be easily maintained, suggesting that less entrainment effort is needed to keep the phase-lock, than to find the phase-lock. The different alignment strategies of D-Jogger can be applied in different domains such as sports, physical rehabilitation and assistive technologies for movement performance.     

Music Attenuates Excessive Visual Guidance of Skilled Reaching in Advanced but Not Mild Parkinson's Disease

Parkinson''s disease (PD) results in movement and sensory impairments that can be reduced by familiar music. At present, it is unclear whether the beneficial effects of music are limited to lessening the bradykinesia of whole body movement or whether beneficial effects also extend to skilled movements of PD subjects. This question was addressed in the present study in which control and PD subjects were given a skilled reaching task that was performed with and without accompanying preferred musical pieces. Eye movements and limb use were monitored with biomechanical measures and limb movements were additionally assessed using a previously described movement element scoring system. Preferred musical pieces did not lessen limb and hand movement impairments as assessed with either the biomechanical measures or movement element scoring. Nevertheless, the PD patients with more severe motor symptoms as assessed by Hoehn and Yahr (HY) scores displayed enhanced visual engagement of the target and this impairment was reduced during trials performed in association with accompanying preferred musical pieces. The results are discussed in relation to the idea that preferred musical pieces, although not generally beneficial in lessening skilled reaching impairments, may normalize the balance between visual and proprioceptive guidance of skilled reaching.     

Quantifying Auditory Temporal Stability in a Large Database of Recorded Music

“Moving to the beat” is both one of the most basic and one of the most profound means by which humans (and a few other species) interact with music. Computer algorithms that detect the precise temporal location of beats (i.e., pulses of musical “energy”) in recorded music have important practical applications, such as the creation of playlists with a particular tempo for rehabilitation (e.g., rhythmic gait training), exercise (e.g., jogging), or entertainment (e.g., continuous dance mixes). Although several such algorithms return simple point estimates of an audio file’s temporal structure (e.g., “average tempo”, “time signature”), none has sought to quantify the temporal stability of a series of detected beats. Such a method-a “Balanced Evaluation of Auditory Temporal Stability” (BEATS)–is proposed here, and is illustrated using the Million Song Dataset (a collection of audio features and music metadata for nearly one million audio files). A publically accessible web interface is also presented, which combines the thresholdable statistics of BEATS with queryable metadata terms, fostering potential avenues of research and facilitating the creation of highly personalized music playlists for clinical or recreational applications.     

Sampling or Intermittency in Hand Control System Dynamics

A hand control model is proposed. Investigation of the hand's intermittency synchronization shows it corresponds to an input-synchronized sampler rather than the clock-synchronized sampler more typical of engineering systems. A velocity control mechanism, similar to that in an eye tracking system is shown to be absent in the hand. A quantitative transfer function for predictable inputs serves further to define the hand's input adaptive characteristics. Stability margin adjustments of a linear reduced model enabled us to match the available quantitative data. The most exciting result of this study is the evidence for intermittency: a refractory period shown in the short pulse experiment, peaks in the frequency response experiments, and a saccadic sequence of steps in response to an open loop step input and to a closed loop ramp input.     

Temporal Variation of Bacterial Respiration and Growth Efficiency in Tropical Coastal Waters

We investigated the temporal variation of bacterial production, respiration, and growth efficiency in the tropical coastal waters of Peninsular Malaysia. We selected five stations including two estuaries and three coastal water stations. The temperature was relatively stable (averaging around 29.5°C), whereas salinity was more variable in the estuaries. We also measured dissolved organic carbon and nitrogen (DOC and DON, respectively) concentrations. DOC generally ranged from 100 to 900 μM, whereas DON ranged from 0 to 32 μM. Bacterial respiration ranged from 0.5 to 3.2 μM O₂ h⁻¹, whereas bacterial production ranged from 0.05 to 0.51 μM C h⁻¹. Bacterial growth efficiency was calculated as bacterial production/(bacterial production + respiration), and ranged from 0.02 to 0.40. Multiple correlation analyses revealed that bacterial production was dependent upon primary production (r² = 0.169, df = 31, and P < 0.02) whereas bacterial respiration was dependent upon both substrate quality (i.e., DOC/DON ratio) (r² = 0.137, df = 32, and P = 0.03) and temperature (r² = 0.113, df = 36, and P = 0.04). Substrate quality was the most important factor (r² = 0.119, df = 33, and P = 0.04) for the regulation of bacterial growth efficiency. Using bacterial growth efficiency values, the average bacterial carbon demand calculated was from 5.30 to 11.28 μM C h⁻¹. When the bacterial carbon demand was compared with primary productivity, we found that net heterotrophy was established at only two stations. The ratio of bacterial carbon demand to net primary production correlated significantly with bacterial growth efficiency (r² = 0.341, df = 35, and P < 0.001). From nonlinear regression analysis, we found that net heterotrophy was established when bacterial growth efficiency was <0.08. Our study showed the extent of net heterotrophy in these waters and illustrated the importance of heterotrophic microbial processes in coastal aquatic food webs.As our understanding of the marine food web evolves, we recognize the importance of microorganisms in aquatic ecosystems. Bacteria are the main respirers and recycle a large pool of dissolved organic matter to higher trophic levels (6, 13). Therefore, bacterial production is a key process in dissolved organic matter flux. However, the transfer of dissolved organic matter to bacteria is more accurately reflected by bacterial carbon demand (BCD) or carbon consumption (23). One way to obtain BCD from bacterial production is through bacterial growth efficiency (BGE) or growth yield. BGE is an important parameter to evaluate the fate of organic carbon inputs and to determine whether bacteria act as a link (recyclers) or sink (mineralizers). Therefore, understanding the patterns of variation in BGE is fundamental for our knowledge of carbon cycling (14).BGE is essentially the ratio of carbon converted to biomass relative to all the carbon consumed, where carbon consumption is either measured as the sum of bacterial production and respiration (5, 24), dissolved organic matter utilization (3), or both (12). Although bacterial production is frequently measured, bacterial respiration measurements are still scarce (23) and are often derived from production rates assuming constant growth efficiency (7, 30). The use of a constant growth efficiency is, however, not valid in some situations as studies have shown that BGE varies over both time and space (8, 27, 28, 32).From cross-system compilations (15, 38, 49) and a comprehensive study in a temperate salt marsh estuary (4, 5), we begin to understand the factors that affect bacterial growth efficiency. Although substrate quantity and quality affect growth efficiency (4, 15), temperature is also an important factor (49). However, the effect of temperature differs for both bacterial production and bacterial respiration (5) and is distorted by substrate limitation (38).Most of the above studies are from temperate regions where there is marked seasonality in temperature. In temperate regions, the effects of temperature are usually more apparent (5, 32) and can sometimes distort the effects of other factors (4). Although temperature plays a major role in controlling heterotrophic activity in temperate regions, it plays a lesser role in the tropics, where temperatures are more stable and relatively higher. Tropical oceans cover about 40% of the global ocean (37), and yet knowledge of the structure and function of this ecosystem remains limited, especially in the region of Southeast Asia (29). Only a few related studies are available, and those are from tropical coastal waters in Goa, India (45), and mangrove and estuarine waters in Peninsular Malaysia (27, 28). Substrate quality is often suggested as a more important factor than temperature (27, 28, 45).In this paper, we addressed the following question: What is the effect of substrate quality and temperature toward BGE in tropical coastal waters? We measured bacterial respiration, production, and growth efficiency in tropical coastal waters and related their variation to changes in temperature and dissolved organic nutrient concentrations. Here, we show that although both temperature and substrate quality affected respiration, BGE was related to substrate quality only.     

Spatial and Temporal Control of Cavitation Allows High In Vitro Transfection Efficiency in the Absence of Transfection Reagents or Contrast Agents

Sonoporation using low-frequency high-pressure ultrasound (US) is a non-viral approach for in vitro and in vivo gene delivery. In this study, we developed a new sonoporation device designed for spatial and temporal control of ultrasound cavitation. The regulation system incorporated in the device allowed a real-time control of the cavitation level during sonoporation. This device was evaluated for the in vitro transfection efficiency of a plasmid coding for Green Fluorescent Protein (pEGFP-C1) in adherent and non-adherent cell lines. The transfection efficiency of the device was compared to those observed with lipofection and nucleofection methods. In both adherent and non-adherent cell lines, the sonoporation device allowed high rate of transfection of pEGFP-C1 (40–80%), as determined by flow cytometry analysis of GFP expression, along with a low rate of mortality assessed by propidium iodide staining. The transfection efficiency and toxicity of sonoporation on the non-adherent cell lines Jurkat and K562 were similar to those of nucleofection, while these two cell lines were resistant to transfection by lipofection. Moreover, sonoporation was used to produce three stably transfected human lymphoma and leukemia lines. Significant transfection efficiency was also observed in two fresh samples of human acute myeloid leukemia cells. In conclusion, we developed a user-friendly and cost-effective ultrasound device, well adapted for routine in vitro high-yield transfection experiments and which does not require the use of any transfection reagent or gas micro-bubbles.     

Division of Labor in Hand Usage Is Associated with Higher Hand Performance in Free-Ranging Bonnet Macaques,Macaca radiata

A practical approach to understanding lateral asymmetries in body, brain, and cognition would be to examine the performance advantages/disadvantages associated with the corresponding functions and behavior. In the present study, we examined whether the division of labor in hand usage, marked by the preferential usage of the two hands across manual operations requiring maneuvering in three-dimensional space (e.g., reaching for food, grooming, and hitting an opponent) and those requiring physical strength (e.g., climbing), is associated with higher hand performance in free-ranging bonnet macaques, Macaca radiata. We determined the extent to which the macaques exhibit laterality in hand usage in an experimental unimanual and a bimanual food-reaching task, and the extent to which manual laterality is associated with hand performance in an experimental hand-performance-differentiation task. We observed negative relationships between (a) the latency in food extraction by the preferred hand in the hand-performance-differentiation task (wherein, lower latency implies higher performance), the preferred hand determined using the bimanual food-reaching task, and the normalized difference between the performance of the two hands, and (b) the normalized difference between the performance of the two hands and the absolute difference between the laterality in hand usage in the unimanual and the bimanual food-reaching tasks (wherein, lesser difference implies higher manual specialization). Collectively, these observations demonstrate that the division of labor between the two hands is associated with higher hand performance.