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1.
J Sports Sci ; 42(8): 720-727, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38833336

RESUMEN

A key focus of sports science research is the identification of quantitative assessments that can predict players' on-field performance and developmental potential. Despite efforts to establish predictive models, there are few validated measures that show reliable associations and large gaps in understanding. Here, we test a multidimensional battery of assessments developed through the USA Baseball, Prospect Development Pipeline that capture strength and functional movement abilities, and anthropometric characteristics, in a two-year cohort of collegiate baseball players from the Appalachian League. Swing propensity metrics for Zone Contact Percentage (ZCP: proportion pitches in strike zone swung at and hit) and Hard-Hit Percentage (HHP: proportion in-play balls with exit velocity ≥ 95 mph) were calculated on 189 players. Models testing hierarchical combinations of anthropometric and anthropometric plus assessment data were implemented using nested cross-validation with random forest and elastic net regression. Results indicate that anthropometric features account for 29% of variance in ZCP and 50-55% of HHP, while the addition of assessment contributed an additional 1-3% to ZCP and 5-12% to HHP, with top predictors coming from PDP strength and power assessments. These findings delineate contributions of andromorphic and physical abilities to in-game baseball performance using a validated assessment battery and advanced game statistics.


Asunto(s)
Antropometría , Rendimiento Atlético , Béisbol , Fuerza Muscular , Béisbol/fisiología , Humanos , Rendimiento Atlético/fisiología , Adulto Joven , Masculino , Fuerza Muscular/fisiología , Adolescente , Destreza Motora/fisiología
2.
World J Surg ; 45(7): 2148-2154, 2021 07.
Artículo en Inglés | MEDLINE | ID: mdl-33738523

RESUMEN

BACKGROUND: Neck ultrasound (US) and Technetium-99 m Sestamibi (MIBI) scan are the most commonly used imaging studies for preoperative localization of parathyroid adenomas. The aim of this study was to determine the added value of MIBI scan and its effect on the operative plan via a hypothetical model where a stepwise approach is conducted and MIBI is considered only after the ultrasound is evaluated. METHODS: Patients who underwent parathyroidectomy for primary hyperparathyroidism (PHPT) between 2012 and 2019 at two tertiary centers were included. Data collected included demographic data, preoperative workup, operative findings and follow-up. The added value of MIBI scans was determined for patients with positive ultrasound. RESULTS: A total of 513 patients with positive US result and a MIBI scan were included. If a stepwise approach was conducted then MIBI scan would not change the operative plan in 492 (95.9%). Among the remaining 21 patients, MIBI scan would correctly change the ultrasound-based operative plan in only 12 (2.3%) patients, while incorrectly change the plan in 9 (1.8%), resulting in unnecessary exploration of the contralateral side. In patients with sonographic appearance of a parathyroid gland larger than 1.2 cm, MIBI scan would correctly change the operative plan in only 1 of the 287 (0.35%) patients. CONCLUSIONS: Our study suggests that the routine use of MIBI scans may have limited added value in patients with PHPT and a positive neck ultrasound, especially in those with adenoma size larger than 1.2 cm. Positive ultrasound alone may be sufficient for the preoperative localization of parathyroid disease.


Asunto(s)
Hiperparatiroidismo Primario , Neoplasias de las Paratiroides , Humanos , Hiperparatiroidismo Primario/diagnóstico por imagen , Hiperparatiroidismo Primario/cirugía , Neoplasias de las Paratiroides/diagnóstico por imagen , Neoplasias de las Paratiroides/cirugía , Paratiroidectomía , Radiofármacos , Tecnecio , Tecnecio Tc 99m Sestamibi , Ultrasonografía
3.
Neuroimage ; 218: 116959, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32442638

RESUMEN

Neuroimaging evidence suggests that the aging brain relies on a more distributed set of cortical regions than younger adults in order to maintain successful levels of performance during demanding cognitive tasks. However, it remains unclear how task demands give rise to this age-related expansion in cortical networks. To investigate this issue, functional magnetic resonance imaging was used to measure univariate activity, network connectivity, and cognitive performance in younger and older adults during a working memory (WM) task. Here, individuals performed a WM task in which they held letters online while reordering them alphabetically. WM load was titrated to obtain four individualized difficulty levels with different set sizes. Network integration-defined as the ratio of within-versus between-network connectivity-was linked to individual differences in WM capacity. The study yielded three main findings. First, as task difficulty increased, network integration decreased in younger adults, whereas it increased in older adults. Second, age-related increases in network integration were driven by increases in right hemisphere connectivity to both left and right cortical regions, a finding that helps to reconcile existing theories of compensatory recruitment in aging. Lastly, older adults with higher WM capacity demonstrated higher levels of network integration in the most difficult task condition. These results shed light on the mechanisms of age-related network reorganization by demonstrating that changes in network connectivity may act as an adaptive form of compensation, with older adults recruiting a more distributed cortical network as task demands increase.


Asunto(s)
Envejecimiento/fisiología , Envejecimiento/psicología , Memoria a Corto Plazo/fisiología , Red Nerviosa/fisiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Mapeo Encefálico , Corteza Cerebral/diagnóstico por imagen , Corteza Cerebral/fisiología , Cognición/fisiología , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Red Nerviosa/diagnóstico por imagen , Neuroimagen , Desempeño Psicomotor/fisiología , Conducta Verbal , Adulto Joven
4.
J Sport Rehabil ; 28(7): 692-698, 2019 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-29952695

RESUMEN

CONTEXT: Concussion management is moving from passive rest strategies to active interventions, including aerobic exercise therapy. Little information is available regarding the feasibility and adherence of these programs. OBJECTIVES: To determine whether an aerobic exercise training program intended for rehabilitation in people with concussion is feasible. Healthy, nonconcussed subjects were studied in this phase 1 trial. DESIGN: Phase 1 parallel-group, randomized controlled trial in a sample of healthy (nonconcussed), recreationally active university students. SETTING: Laboratory. PATIENTS: 40 healthy university students. METHODS: Participants were equally randomized to acute concussion therapy intervention (ACTIVE) training or nontraining groups. All participants completed maximal cardiopulmonary exercise tests on a stationary cycle ergometer at 2 test sessions approximately 14 days apart. During this 2-week study period, ACTIVE training participants completed six 30-minute cycling sessions, progressing from 60% to 80% of the participant's individualized maximal oxygen consumption. A subset of participants (NACTIVE = 12, Nnontraining = 11) wore physical activity monitors throughout the 2-week study period. MAIN OUTCOMES MEASURES: Study protocol and randomization effectiveness, exercise safety and adherence, and progressive intensity of the ACTIVE training procedures. RESULTS: No adverse events occurred during any exercise sessions. Twelve ACTIVE training participants (60%) completed all training sessions, and every participant completed at least 4 sessions. Heart rate increased throughout the training period (P < .001), but symptom changes and training adherence remained stable despite the progressively increasing workload. ACTIVE training participants completed approximately 30 additional minutes of physical activity on training sessions days, although that was not statistically significant (P = .20). CONCLUSIONS: University-aged students were adherent to the ACTIVE training protocol. Future research should investigate the safety and feasibility of aerobic training programs in acutely concussed individuals to determine their appropriateness as a clinical rehabilitation strategy.


Asunto(s)
Terapia por Ejercicio , Cooperación del Paciente , Conmoción Encefálica/rehabilitación , Estudios de Factibilidad , Femenino , Voluntarios Sanos , Frecuencia Cardíaca , Humanos , Masculino , Consumo de Oxígeno , Adulto Joven
5.
Perception ; 46(1): 50-77, 2017 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-27697914

RESUMEN

Several striking visual phenomena involve a physically present stimulus that alternates between being perceived and being "invisible." For example, motion-induced blindness, the Troxler effect, and perceptual filling-in all consist of subjective alternations where an item repeatedly changes from being seen to unseen. In the present study, we explored whether these three specific visual phenomena share any commonalities in their alternation rates and patterns to better understand the mechanisms of each. Data from 69 individuals revealed moderate to strong correlations across the three phenomena for the number of perceptual disappearances and the accumulated duration of the disappearances. Importantly, these effects were not correlated with eye movement patterns (saccades) assessed through eye tracking, differences in motion sensitivity as indexed by dot coherence and speed perception thresholds, or simple reaction time abilities. Principal component analyses revealed a single component that explained 67% of the variance for the number of perceptual reversals and 60% for the accumulated duration of the disappearances. The temporal dynamics of illusory disappearances was also compared for each phenomenon, and normalized durations of disappearances were well fit by a gamma distribution with similar shape parameters for each phenomenon, suggesting that they may be driven by a single oscillatory mechanism.

6.
7.
J Neurosci ; 35(13): 5351-9, 2015 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-25834059

RESUMEN

Practice can improve performance on visual search tasks; the neural mechanisms underlying such improvements, however, are not clear. Response time typically shortens with practice, but which components of the stimulus-response processing chain facilitate this behavioral change? Improved search performance could result from enhancements in various cognitive processing stages, including (1) sensory processing, (2) attentional allocation, (3) target discrimination, (4) motor-response preparation, and/or (5) response execution. We measured event-related potentials (ERPs) as human participants completed a five-day visual-search protocol in which they reported the orientation of a color popout target within an array of ellipses. We assessed changes in behavioral performance and in ERP components associated with various stages of processing. After practice, response time decreased in all participants (while accuracy remained consistent), and electrophysiological measures revealed modulation of several ERP components. First, amplitudes of the early sensory-evoked N1 component at 150 ms increased bilaterally, indicating enhanced visual sensory processing of the array. Second, the negative-polarity posterior-contralateral component (N2pc, 170-250 ms) was earlier and larger, demonstrating enhanced attentional orienting. Third, the amplitude of the sustained posterior contralateral negativity component (SPCN, 300-400 ms) decreased, indicating facilitated target discrimination. Finally, faster motor-response preparation and execution were observed after practice, as indicated by latency changes in both the stimulus-locked and response-locked lateralized readiness potentials (LRPs). These electrophysiological results delineate the functional plasticity in key mechanisms underlying visual search with high temporal resolution and illustrate how practice influences various cognitive and neural processing stages leading to enhanced behavioral performance.


Asunto(s)
Encéfalo/fisiología , Aprendizaje/fisiología , Percepción Visual/fisiología , Adolescente , Adulto , Atención/fisiología , Mapeo Encefálico , Ondas Encefálicas/fisiología , Discriminación en Psicología/fisiología , Electroencefalografía , Potenciales Evocados , Femenino , Humanos , Masculino , Desempeño Psicomotor , Tiempo de Reacción , Adulto Joven
8.
Ultraschall Med ; 37(1): 27-45, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26871408

RESUMEN

The third part of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) Guidelines on Interventional Ultrasound assesses the evidence for ultrasound-guided and assisted interventions in abdominal treatment procedures. Recommendations for clinical practice are presented covering indications, contraindications, safety and efficacy of the broad variety of these techniques. In particular, drainage of abscesses and fluid collections, interventional tumor ablation techniques, interventional treatment of symptomatic cysts and echinococcosis, percutaneous transhepatic cholangiography and drainage, percutaneous gastrostomy, urinary bladder drainage, and nephrostomy are addressed (short version; a long version is published online).


Asunto(s)
Abdomen/diagnóstico por imagen , Ultrasonografía Intervencional/métodos , Absceso Abdominal/diagnóstico por imagen , Absceso Abdominal/cirugía , Neoplasias Abdominales/diagnóstico por imagen , Neoplasias Abdominales/cirugía , Colangiografía/métodos , Quistes/diagnóstico por imagen , Quistes/cirugía , Drenaje/métodos , Gastrostomía/métodos , Alemania , Humanos , Neoplasias Hepáticas/diagnóstico por imagen , Neoplasias Hepáticas/secundario , Neoplasias Hepáticas/cirugía , Nefrostomía Percutánea/métodos , Seguridad del Paciente , Garantía de la Calidad de Atención de Salud , Resultado del Tratamiento , Vejiga Urinaria/diagnóstico por imagen , Vejiga Urinaria/cirugía
9.
Ultraschall Med ; 37(1): E1-E32, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26670019

RESUMEN

The third part of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) Guidelines on Interventional Ultrasound (INVUS) assesses the evidence for ultrasound-guided and assisted interventions in abdominal treatment procedures. Recommendations for clinical practice are presented covering indications, contraindications, and safe and effective performance of the broad variety of these techniques. In particular, drainage of abscesses and fluid collections, interventional tumor ablation techniques, interventional treatment of symptomatic cysts and echinococcosis, percutaneous transhepatic cholangiography and drainage, percutaneous gastrostomy, urinary bladder drainage, and nephrostomy are addressed (long version).


Asunto(s)
Abdomen/diagnóstico por imagen , Abdomen/cirugía , Medicina Basada en la Evidencia , Sociedades Médicas , Ultrasonografía Intervencional/métodos , Absceso Abdominal/diagnóstico por imagen , Absceso Abdominal/cirugía , Colecistostomía/métodos , Neoplasias Colorrectales/diagnóstico por imagen , Neoplasias Colorrectales/cirugía , Terapia Combinada , Quistes/diagnóstico por imagen , Quistes/cirugía , Gastrostomía/métodos , Alemania , Humanos , Neoplasias Renales/diagnóstico por imagen , Neoplasias Renales/cirugía , Hepatopatías/diagnóstico por imagen , Hepatopatías/cirugía , Neoplasias Hepáticas/diagnóstico por imagen , Neoplasias Hepáticas/secundario , Neoplasias Hepáticas/cirugía , Nefrostomía Percutánea/métodos , Cuidados Paliativos/métodos , Paracentesis/métodos , Escleroterapia/métodos
10.
Z Gastroenterol ; 53(6): 579-90, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-26075369

RESUMEN

Local ablative therapies have become an important part in the portfolio of treatment for patients with malignant tumors especially in the liver. Although percutaneous ethanol injection still plays a role, current guidelines favor radiofrequency ablation with a higher efficacy for complete tumor destruction. Nevertheless transplantation and surgical resection remain the gold standard due to their superiority in local control and improved survival. In this manuscript we discuss the technique in detail.


Asunto(s)
Ablación por Catéter/métodos , Hepatectomía/métodos , Neoplasias Hepáticas/terapia , Trasplante de Hígado/métodos , Escleroterapia/métodos , Cirugía Asistida por Computador/métodos , Etanol/uso terapéutico , Humanos , Neoplasias Hepáticas/diagnóstico , Soluciones Esclerosantes/uso terapéutico
11.
J Vis ; 15(6): 4, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26024451

RESUMEN

Periodic visual stimulation and analysis of the resulting steady-state visual evoked potentials were first introduced over 80 years ago as a means to study visual sensation and perception. From the first single-channel recording of responses to modulated light to the present use of sophisticated digital displays composed of complex visual stimuli and high-density recording arrays, steady-state methods have been applied in a broad range of scientific and applied settings.The purpose of this article is to describe the fundamental stimulation paradigms for steady-state visual evoked potentials and to illustrate these principles through research findings across a range of applications in vision science.


Asunto(s)
Potenciales Evocados Visuales/fisiología , Investigación Biomédica , Humanos , Visión Ocular
12.
J Cogn Neurosci ; 26(9): 1949-65, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24666126

RESUMEN

Cognitive neuroscience, as a discipline, links the biological systems studied by neuroscience to the processing constructs studied by psychology. By mapping these relations throughout the literature of cognitive neuroscience, we visualize the semantic structure of the discipline and point to directions for future research that will advance its integrative goal. For this purpose, network text analyses were applied to an exhaustive corpus of abstracts collected from five major journals over a 30-month period, including every study that used fMRI to investigate psychological processes. From this, we generate network maps that illustrate the relationships among psychological and anatomical terms, along with centrality statistics that guide inferences about network structure. Three terms--prefrontal cortex, amygdala, and anterior cingulate cortex--dominate the network structure with their high frequency in the literature and the density of their connections with other neuroanatomical terms. From network statistics, we identify terms that are understudied compared with their importance in the network (e.g., insula and thalamus), are underspecified in the language of the discipline (e.g., terms associated with executive function), or are imperfectly integrated with other concepts (e.g., subdisciplines like decision neuroscience that are disconnected from the main network). Taking these results as the basis for prescriptive recommendations, we conclude that semantic analyses provide useful guidance for cognitive neuroscience as a discipline, both by illustrating systematic biases in the conduct and presentation of research and by identifying directions that may be most productive for future research.


Asunto(s)
Mapeo Encefálico , Encéfalo/fisiología , Cognición/fisiología , Vías Nerviosas/fisiología , Neurociencias , Semántica , Encéfalo/irrigación sanguínea , Bases de Datos Factuales/estadística & datos numéricos , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Vías Nerviosas/irrigación sanguínea , Oxígeno/sangre
13.
J Cogn Neurosci ; 26(5): 1021-38, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-24345171

RESUMEN

In this study, we leveraged the high temporal resolution of EEG to examine the neural mechanisms underlying the flexible regulation of cognitive control that unfolds over different timescales. We measured behavioral and neural effects of color-word incongruency, as different groups of participants performed three different versions of color-word Stroop tasks in which the relative timing of the color and word features varied from trial to trial. For this purpose, we used a standard Stroop color identification task with equal congruent-to-incongruent proportions (50%/50%), along with two versions of the "Reverse Stroop" word identification tasks, for which we manipulated the incongruency proportion (50%/50% and 80%/20%). Two canonical ERP markers of neural processing of stimulus incongruency, the frontocentral negative polarity incongruency wave (NINC) and the late positive component (LPC), were evoked across the various conditions. Results indicated that color-word incongruency interacted with the relative feature timing, producing greater neural and behavioral effects when the task-irrelevant stimulus preceded the target, but still significant effects when it followed. Additionally, both behavioral and neural incongruency effects were reduced by nearly half in the word identification task (Reverse Stroop 50/50) relative to the color identification task (Stroop 50/50), with these effects essentially fully recovering when incongruent trials appeared only infrequently (Reverse Stroop 80/20). Across the conditions, NINC amplitudes closely paralleled RTs, indicating this component is sensitive to the overall level of stimulus conflict. In contrast, LPC amplitudes were largest with infrequent incongruent trials, suggesting a possible readjustment role when proactive control is reduced. These findings thus unveil distinct control mechanisms that unfold over time in response to conflicting stimulus input under different contexts.


Asunto(s)
Encéfalo/fisiología , Cognición/fisiología , Estimulación Luminosa/métodos , Desempeño Psicomotor/fisiología , Tiempo de Reacción/fisiología , Adolescente , Adulto , Femenino , Humanos , Masculino , Adulto Joven
14.
Sports Biomech ; : 1-19, 2024 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-38190251

RESUMEN

This study examined the relationship between psychomotor abilities and baseball performance by analysing data from 379 athletes who participated in the USA Baseball, Prospect Development Pipeline (PDP). Hit and pitch metrics were generated during practice sessions using the RapsodoTM System. Data were compared through exploratory factor analysis and hierarchical regression. Factor analysis grouped batter's PDP evaluations into four latent variables accounting for 63% of variance. Pitcher performance grouped into three factors accounting for 51% of variance. Regression on batter data revealed a significant demographic/anthropometric base model with height, weight, and age that accounted for 58% of the batted ball speed (R2 = 0.581). Player position explained 2% of the variance (R2 = 0.604), and PDP evaluation scores contributed an additional 3% (R2 = 0.631). Regression of pitcher data showed a significant base demographic/anthropometric model accounting for 36% of fastball pitch speeds (R2 = 0.363), with the PDP evaluation scores adding 6% additional variance (R2 = 0.424). Uniformly, assessments of lower body strength added the greatest predictive information. Hand grip strength did not correlate with pitch metrics. While demographics/anthropometrics are major contributors to batted and pitched ball speed, position and psychomotor variables add statistically significant contributions and may be of practical value for player selection.

15.
Neuroimage ; 67: 77-88, 2013 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-23116814

RESUMEN

The lateral occipital cortex (LOC) activates selectively to images of intact objects versus scrambled controls, is selective for the figure-ground relationship of a scene, and exhibits at least some degree of invariance for size and position. Because of these attributes, it is considered to be a crucial part of the object recognition pathway. Here we show that human LOC is critically involved in perceptual decisions about object shape. High-density EEG was recorded while subjects performed a threshold-level shape discrimination task on texture-defined figures segmented by either phase or orientation cues. The appearance or disappearance of a figure region from a uniform background generated robust visual evoked potentials throughout retinotopic cortex as determined by inverse modeling of the scalp voltage distribution. Contrasting responses from trials containing shape changes that were correctly detected (hits) with trials in which no change occurred (correct rejects) revealed stimulus-locked, target-selective activity in the occipital visual areas LOC and V4 preceding the subject's response. Activity that was locked to the subjects' reaction time was present in the LOC. Response-locked activity in the LOC was determined to be related to shape discrimination for several reasons: shape-selective responses were silenced when subjects viewed identical stimuli but their attention was directed away from the shapes to a demanding letter discrimination task; shape-selectivity was present across four different stimulus configurations used to define the figure; LOC responses correlated with participants' reaction times. These results indicate that decision-related activity is present in the LOC when subjects are engaged in threshold-level shape discriminations.


Asunto(s)
Mapeo Encefálico/métodos , Toma de Decisiones/fisiología , Electroencefalografía/métodos , Percepción de Forma/fisiología , Lóbulo Occipital/fisiología , Corteza Visual/fisiología , Adulto , Femenino , Humanos , Masculino
16.
J Cogn Neurosci ; 24(9): 1834-48, 2012 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-22360623

RESUMEN

Humans are able to continuously monitor environmental situations and adjust their behavioral strategies to optimize performance. Here we investigate the behavioral and brain adjustments that occur when conflicting stimulus elements are, or are not, temporally predictable. ERPs were collected while manual response variants of the Stroop task were performed in which the SOAs between the relevant color and irrelevant word stimulus components were either randomly intermixed or held constant within each experimental run. Results indicated that the size of both the neural and behavioral effects of stimulus incongruency varied with the temporal arrangement of the stimulus components, such that the random-SOA arrangements produced the greatest incongruency effects at the earliest irrelevant first SOA (-200 msec) and the constant-SOA arrangements produced the greatest effects with simultaneous presentation. These differences in conflict processing were accompanied by rapid (∼150 msec) modulations of the sensory ERPs to the irrelevant distractor components when they occurred consistently first. These effects suggest that individuals are able to strategically allocate attention in time to mitigate the influence of a temporally predictable distractor. As these adjustments are instantiated by the participants without instruction, they reveal a form of rapid strategic learning for dealing with temporally predictable stimulus incongruency.


Asunto(s)
Atención/fisiología , Conflicto Psicológico , Potenciales Evocados Visuales/fisiología , Solución de Problemas/fisiología , Adulto , Análisis de Varianza , Electroencefalografía , Femenino , Fijación Ocular , Humanos , Masculino , Valor Predictivo de las Pruebas , Tiempo de Reacción/fisiología , Factores de Tiempo , Percepción Visual/fisiología
17.
J Eye Mov Res ; 14(2)2021 Mar 10.
Artículo en Inglés | MEDLINE | ID: mdl-33828818

RESUMEN

Expertise in laparoscopic surgery is realized through both manual dexterity and efficient eye movement patterns, creating opportunities to use gaze information in the educational process. To better understand how expert gaze behaviors are acquired through deliberate practice of technical skills, three surgeons were assessed and five novices were trained and assessed in a 5-visit protocol on the Fundamentals of Laparoscopic Surgery peg transfer task. The task was adjusted to have a fixed action sequence to allow recordings of dwell durations based on pre-defined areas of interest (AOIs). Trained novices were shown to reach more than 98% (M = 98.62%, SD = 1.06%) of their behavioral learning plateaus, leading to equivalent behavioral performance to that of surgeons. Despite this equivalence in behavioral performance, surgeons continued to show significantly shorter dwell durations at visual targets of current actions and longer dwell durations at future steps in the action sequence than trained novices (ps ≤ .03, Cohen's ds > 2). This study demonstrates that, while novices can train to match surgeons on behavioral performance, their gaze pattern is still less efficient than that of surgeons, motivating surgical training programs to involve eye tracking technology in their design and evaluation.

18.
Neuroimage ; 52(4): 1621-32, 2010 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-20452445

RESUMEN

Successful behavior requires a finely-tuned interplay of initiating and inhibiting motor programs to react effectively to constantly changing environmental demands. One particularly useful paradigm for investigating inhibitory motor control is the Stop-signal task, where already-initiated responses to Go-stimuli are to be inhibited upon the rapid subsequent presentation of a Stop-stimulus (yielding successful and unsuccessful Stop-trials). Despite the extensive use of this paradigm in functional neuroimaging, there is no consensus on which functional comparison to use to characterize response-inhibition-related brain activity. Here, we utilize conjunction analyses of successful and unsuccessful Stop-trials that are each contrasted against a reference condition. This conjunction approach identifies processes common to both Stop-trial types while excluding processes specific to either, thereby capitalizing on the presence of some response-inhibition-related activity in both conditions. Using this approach on fMRI data from human subjects, we identify a network of brain structures that was linked to both types of Stop-trials, including lateral-inferior frontal and medial frontal cortical areas and the caudate nucleus. In addition, comparisons with a reference condition matched for visual stimulation identified additional activity in the right inferior parietal cortex that may play a role in enhancing the processing of the Stop-stimuli. Finally, differences in stopping efficacy across subjects were associated with variations in activity in the left anterior insula. However, this region was also associated with general task accuracy (which furthermore correlated directly with stopping efficacy), suggesting that it might actually reflect a more general mechanism of performance control that supports response inhibition in a relatively nonspecific way.


Asunto(s)
Corteza Cerebral/fisiología , Cognición/fisiología , Señales (Psicología) , Movimiento/fisiología , Inhibición Neural/fisiología , Percepción Visual/fisiología , Adulto , Femenino , Humanos , Masculino
19.
Cereb Cortex ; 19(11): 2508-21, 2009 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-19321654

RESUMEN

This study investigated neural processing interactions during Stroop interference by varying the temporal separation of relevant and irrelevant features of congruent, neutral, and incongruent colored-bar/color-word stimulus components. High-density event-related potentials (ERPs) and behavioral performance were measured as participants reported the bar color as quickly as possible, while ignoring the color words. The task-irrelevant color words could appear at 1 of 5 stimulus onset asynchronies (SOAs) relative to the task-relevant bar-color occurrence: -200 or -100 ms before, +100 or +200 ms after, or simultaneously. Incongruent relative to congruent presentations elicited slower reaction times and higher error rates (with neutral in between), and ERP difference waves containing both an early, negative-polarity, central-parietal deflection, and a later, more left-sided, positive-polarity component. These congruency-related differences interacted with SOA, showing the greatest behavioral and electrophysiological effects when irrelevant stimulus information preceded the task-relevant target and reduced effects when the irrelevant information followed the relevant target. We interpret these data as reflecting 2 separate processes: 1) a 'priming influence' that enhances the magnitude of conflict-related facilitation and conflict-related interference when a task-relevant target is preceded by an irrelevant distractor; and 2) a reduced 'backward influence' of stimulus conflict when the irrelevant distractor information follows the task-relevant target.


Asunto(s)
Atención/fisiología , Mapeo Encefálico/métodos , Encéfalo/fisiología , Conducta de Elección/fisiología , Conflicto Psicológico , Variación Contingente Negativa/fisiología , Solución de Problemas/fisiología , Adolescente , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Test de Stroop , Adulto Joven
20.
Nat Commun ; 10(1): 895, 2019 03 05.
Artículo en Inglés | MEDLINE | ID: mdl-30837464

RESUMEN

Sleep is essential to all animals with a nervous system. Nevertheless, the core cellular function of sleep is unknown, and there is no conserved molecular marker to define sleep across phylogeny. Time-lapse imaging of chromosomal markers in single cells of live zebrafish revealed that sleep increases chromosome dynamics in individual neurons but not in two other cell types. Manipulation of sleep, chromosome dynamics, neuronal activity, and DNA double-strand breaks (DSBs) showed that chromosome dynamics are low and the number of DSBs accumulates during wakefulness. In turn, sleep increases chromosome dynamics, which are necessary to reduce the amount of DSBs. These results establish chromosome dynamics as a potential marker to define single sleeping cells, and propose that the restorative function of sleep is nuclear maintenance.


Asunto(s)
Cromosomas/genética , Roturas del ADN de Doble Cadena , Reparación del ADN/fisiología , Neuronas/metabolismo , Sueño/fisiología , Animales , Animales Modificados Genéticamente , Núcleo Celular/genética , Núcleo Celular/metabolismo , Cromosomas/metabolismo , Femenino , Masculino , Microscopía Confocal , Modelos Animales , Neuronas/citología , Imagen de Lapso de Tiempo , Pez Cebra
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