Long-term motor training enhances functional connectivity between semantic and motor regions in an effector-specific manner: evidence from elite female football athletes.

The relation between the action verb semantic processing and sensorimotor experience remains controversial. In this study, we examined whether plasticity changes in brain are specifically related to semantic processing of foot action verbs when long-term motor training is mainly aimed at the foot. To address this question, we acquired resting-state functional magnetic resonance imaging scans and behavioral data from a verb two-choice task from female expertise football players and football novices. We compared the resting-state functional connectivity (rsFC) differences between experts and novices using motor execution regions and general semantic regions (left anterior temporal lobe, lATL) as seed, and explored the neural correlates of behavioral performance. Here, the drift rate (v) parameter of the drift diffusion model (DDM) was used to capture the semantic processing capability. We found experts showed increased correlation between lATL subregions and important brain regions for motor processing, including supplementary motor area (SMA), bilateral paracentral lobule (PL), superior parietal lobule and inferior parietal lobule, in contrast to novices. Further predictive model analysis showed the FC found in rsFC analysis can significantly predict drift rate of foot action verb in both experts and novices, but not drift rate of hand action verb. Our findings therefore establish a connection between effector-related semantic processing and the plasticity changes in brain functional connectivity, attributable to long-term foot-related motor training. This provides evidence supporting the view that semantic processing is fundamentally rooted in the sensorimotor system.

Suppression on the basis of template for rejection is reactive: Evidence from human electrophysiology.

According to most theories of attention, the selection of task-relevant visual information can be enhanced by holding them in visual working memory (VWM). However, there has been a long-standing debate concerning whether similar optimization can also be achieved for task-irrelevant information, known as a "template for rejection". The present study aimed to explore this issue by examining the consequence of cue distractors before visual search tasks. For this endeavor, we manipulated the display heterogeneity by using two distractor conditions, salient and non-salient, to explore the extent to which holding the distractor color in VWM might affect attentional selection. We measured the reaction times of participants while their EEG activity was recorded. The results showed that WM-matched distractors did not improve reaction times but rather slowed them down in both tasks. Event-related potential (ERP) results showed that the display heterogeneity had no modulatory effect on the degree of distractor suppression. Even in the salient distractor condition, the WM-matched distractor received no greater suppression. Furthermore, the WM-matched distractor but not the neutral distractor elicited an N2pc before the PD in salient distractor conditions. This suggests that the template for rejection operates reactively since suppression occurs after extra attentional processes to the distractor. Moreover, the presence of WM-matched distractors led to a reduction of P3b, indicating a competition between target processing and WM-matched distractor rejection. Our findings provide insights into the mechanisms underlying the optimization of attentional selection, and have implications for future studies aimed at understanding the role of VWM in cognition.

Different prioritization states of working memory representations affect visual searches: Evidence from an event-related potential study.

Previous evidence has shown that the contents of working memory (WM) can bias visual selection. However, not much is known about how WM effects change when the WM representation is held in different prioritization states. Here, we investigated this problem using event-related potentials. Subjects maintained two colors in WM while performing a search task. One of the colors was retro-cued, indicating that it was 80 % likely to be the target of the memory test. During the search display, one of the distractors was a salient color singleton, and this singleton distractor could carry the same color as the cued WM representation, the uncued WM representation, or be irrelevant to the memory content. Behaviorally, the memory test performance was found to be better for the cued color than for the uncued color, and we observed lower search accuracy (ACC) and longer search reaction time (RT) when the singleton distractor matched the cued WM representation than when it matched an uncued or an irrelevant WM representation. Event-related potential (ERP) data showed that the P3 amplitude of cue-color distractor conditions was smaller than that of uncued-color distractor conditions and irrelevant-color distractor conditions. These findings clearly indicate that prioritizing an item for enhanced representational quality enables the item to bias attention to a greater extent.

Saliency affects attentional capture and suppression of abrupt-onset and color singleton distractors: Evidence from event-related potential studies.

Attention is the process of selecting relevant information and suppressing irrelevant information. However, it is still controversial whether attentional capture by salient but task-irrelevant stimuli operates in a bottom-up fashion (stimulus-driven theory) or a top-down fashion (goal-driven theory) or if even salient distractors can be suppressed before capturing attention (signal suppression theory). In the present study, we investigated how saliency affects attentional capture (indexed by N2-posterior-contralateral [N2pc]) and suppression (indexed by distractor positivity [PD ]) of abrupt-onset and color singleton distractors in a visual search task. Experiment 1 showed that an abrupt-onset distractor elicited both N2pc and PD , while a color singleton distractor elicited only PD . Moreover, the abrupt-onset distractor elicited a larger N2pc and a larger PD relative to the color singleton distractor. In addition, both distractors elicited an early positive component, the positivity posterior contralateral (Ppc), which was also larger for abrupt onsets than for color singletons. Experiment 2 further demonstrated that when both the abrupt onset and color singleton were designed as targets, and thus required no attentional suppression, Ppc was elicited, but PD was not. This corroborated the finding in Experiment 1 that the later PD , not the early Ppc, reflected attentional suppression. Therefore, a more salient distractor demonstrates stronger early perceptual processing, can capture attention better and needs more attentional resources to be suppressed later. Based on these results, a three-stage hypothesis is proposed, in which the saliency of a distractor modulates processing at early perception, attentional capture, and suppression stages.

A bilateral SPCN is elicited by to-be-memorized visual stimuli displayed along the vertical midline.

We recently showed that deploying attention to target stimuli displayed along the vertical meridian elicits a bilateral N2pc, that we labeled N2pcb (Psychophysiology). Here we investigated whether a different component, the sustained posterior contralateral negativity (SPCN), shows the same property when a varying number of visual stimuli are displayed either laterally or on the vertical meridian. We displayed one or two cues that designated candidate targets to be detected in a search array that was displayed after a retention interval. The cues were either on the horizontal meridian or on the vertical meridian. When the cues were on the horizontal meridian, we observed an N2pc followed by an SPCN in their classic form, as negativity increments contralateral to the cues. As expected, SPCN amplitude was greater when two cues had to be memorized than when only one cue had to be memorized. When the cues were on the vertical meridian, we observed an N2pcb followed by a bilateral SPCN (or SPCNb). Critically, like SPCN, SPCNb amplitude was greater when two cues had to be memorized than when only one cue had to be memorized. A series of additional parametrical and topographical comparisons between N2pcb and SPCNb revealed similarities but also some important differences between these two components that we interpreted as evidence for their distinct neural sources.

[Rapid and simultaneous determination of thirteen organic phosphorous pesticide residues in spinach using gas chromatography-mass spectrometry coupled with stomach large volume injection and mini solid phase extraction].

A stomach large volume injection-gas chromatography-mass spectrometry (LVI-GC-MS) coupled with mini solid phase extraction (SPE) method for the rapid and simultaneous determination of 13 organic phosphorous pesticide residues in spinach samples is presented. The compounds were identified with their retention times and the abundance ratios of qualifier and target ions. Quantification was calculated based on the extraction of spiking standards in a blank sample. The limit of detection (LOD) was determined by the experimental value of the signal-to-noise ratio of 3:1, and the limit of quantification (LOQ) was defined at the experimental value of the signal-to-noise ratio of 10:1. The recoveries obtained ranged from 76.8% to 114.0% with the relative standard deviations between 1.5% and 17.6% except dimethoate. The LODs ranged from 0.5 to 25 microg/kg. This simple, rapid and reliable method has wide applications for the simultaneous determination of multiple pesticide residues in spinach and possibly other species.

[Determination of polychlorinated dibenzo-p-dioxins and dibenzo-furans in sediment by accelerated solvent extraction, fluid management systems and high resolution gas chromatography/high resolution mass spectrometry].

A rapid, sensitive and accurate method has been developed for the determination of seventeen 2, 3, 7, 8-substituted congeners of polychlorinated dibenzo-p-dioxins and dibenzo-furans (PCDD/Fs) in sediment using isotope dilution high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS). Dibenzo-p-dioxins and dibenzo-furans were extracted from samples by accelerated solvent extraction (ASE) and then purified by fluid management systems (FMS) with silica column, alumina column and carbon column. Confirmation and quantitative analysis at pg/g level of PCDD/Fs were performed by HRGC/HRMS using voltage selective ion record (VSIR) mode. Recoveries of fifteen isotopically labeled compound solutions (LCS) and the precision and recovery standards (PAR) were found to be in the range of 49.8% -85.3% and 93.2% - 113.8%, respectively. The detection limits of the method for both 2, 3, 7, 8-tetrachloro-dibenzo-furan (TCDF) and 2, 3, 7, 8-tetrachloro-dibenzo-p-dioxin (TCDD) were determined to be 0.1 pg/g. This method not only meets the requirements of international standards, but also shortens analysis time from 2 weeks to 2 days.

[Influence of body mass index and age on deep vein thrombosis after total hip and knee arthroplasty].

OBJECTIVE: To analyze the influence of the body mass index (BMI) and age on deep vein thrombosis (DVT) after the total hip arthroplasty (THA) or total knee arthroplasty(TKA) in Chinese patients who received prophylactic treatment for DVT. METHODS: We used a randomized clinical case-control study. From April 2004 to August 2004, we performed THA and TKA for 95 patients (128 hips and knees). There were 27 men and 68 women with an average age of 60 years (range, 23-78) at surgery, and with an average BMI of 25.88 kg/m2 (range, 14.34-40.39) before surgery. All the patients were given low-molecular-weight heparin for 7-10 days pre- and postoperatively to prevent DVT. Color Doppler ultrasonography was used to detect DVT of bilateral lower extremities in all the patients before operation and 7-10 days after operation. The patients were divided into 4 groups according to their BMI:the non-obese group (BMI < or = 25.00 kg/m2), the overweight group (BMI, 25.01-27.00 kg/m2), the obese group (BMI, 27.01-30.00 kg/m2), and the morbidly obese group (BMI > 30.00 kg/m2); and they were also divided into 4 groups according to their ages (< or =40, 41-60, 61-70, >70 yr) so as to analyze the influence of the BMI and age on DVT. RESULTS: The total incidence of DVT in all the patients was 47.4% (45/95) and the incidence of proximal DVT was 3.2%. Forty-five patients had DVT and 50 patients had no DVT. The average BMI of the patients with DVT was significantly higher than that of the patients with no DVT (P < 0.05). The overweight, obese, and morbidly obese patients had an odds ratio of 7.04, 4.8, and 9.6 for DVT compared with the non-obese patients (P < 0.05); but the obese group had a less risk than the other 2 groups. The 41-60, 61-70, and > 70-year-old patients had an odds ratio of 24.0, 38.2, and 24.4 for DVT compared with the < or = 40-year-old patients (P < 0.05). CONCLUSION: Obesity (BMI> 25 kg/m2) and an increasing age (>40 yr) are identified as statistically significant risk factors for DVT after THA or TKA, and patients aged 61-70 years are more likely to have DVT than the other patients. We should pay more attention to those obesity and aged patients when they are undergoing the total joint replacement, and we should give them enough prophylaxis and closely observe the symptoms in their bilateral lower extremities after operation, taking ultrasonography or venography to check DVT if necessary, so that we can give them prompt treatment and prevent fatal pulmonary thromboembolism.

[Clinical risk factors for deep vein thrombosis after total hip and knee arthroplasty].

OBJECTIVE: To analyze the clinical risk factors for deep vein thrombosis (DVT) after total hip and knee arthroplasty in Chinese patients who received prophylactic treatment for DVT. METHODS: We evaluated 128 total hip arthroplasty (THA) and total knee arthroplasty (TKA) in 95 patients performed at our center from April 2004 to August 2004, which included 48 THAs in 43 patients and 80 TKAs in 52 patients. There were 27 men and 68 women with a mean age of 59.77 years (range, 23-78 years). All patients had been given low-molecular-weight heparin before operation and for 7-10 days post-operation to prevent DVT. Color Doppler ultrasonography was used to detect DVT of bilateral lower extremities in all patients before operation and at 7-10 days after operation. Nineteen clinical factors were examined preoperation and 7-10 days post-operation in order to analyze their influences on DVT formation after surgery. RESULTS: There were 45 patients who developed DVT after operation. The incidence of DVT in all patients was 47.4% (45/95) and the incidence of proximal DVT was 3.2%. There were more asymptomatic DVT (57.8%, 26/45) than symptomatic ones, and some patients without DVT (14%, 7/50) presented some of the DVT symptoms. Logistic regression analysis demonstrated a definite association of female, obesity (representative by BMI), cement usage and diagnosed RA with DVT with odds ratio of 10.008, 3.094, 8.887, and 0.194 respectively. Other clinical factors had no statistically significant association with DVT. CONCLUSIONS: Female, obesity, and cement usage were the risk factors for DVT after THA and TKA, and diagnosed RA was the protecting factors for DVT after THA and TKA. Other clinical factors such as age, OA, type of implant, monolateral or bilateral operation, duration of anesthesia, surgery and bandage usage for blood control, time for immobilization et al were not the risk factors for DVT.