PURPOSE: To determine if participation in a short-term, high intensity physical education (PE) intervention that respected the multiple goals of the PE curriculum would result in any health- and/or fitness-related improvements for grade four and five students. METHODS: Seventy-six students were divided into a control and intervention group (CG & IG). During 15 successive classes, the IG participated in six minutes of high intensity activities while no changes were made to the structure of the CG’s PE class. Accelerometers and direct observation were used to quantify the percentage of moderate-to-vigorous physical activity (%MVPA). Health- and performance-related measures were assessed pre- and post-intervention. RESULTS: Students spent an average of 27% of their PE class engaged in MVPA. Within this category, the intervention was successful at increasing students’ VPA levels by 7.7%. Observations regarding pedagogical practices are also reported. CONCLUSIONS: Participating in a PE intervention can increase students’ PA levels without compromising the goals of the PE curriculum.

Approximately 85% of Canadians are physically inactive. This project seeks to support physical activity (PA) as a health intervention within primary care using innovative approaches to help people access community-based PA opportunities. We hypothesize that participants will increase and maintain their moderate to vigorous PA in 10-minute bouts (MVPA10Mins) over 10-months. One-hundred-nineteen patients recruited from two primary care facilities did not change their primary outcome of MVPA10Mins from baseline to 10-months. However, secondary outcomes light and total sporadic PA increased by the 4th month and were maintained until 10-months. Furthermore, self-report data including self-efficacy, mood, and quality of life all improved by the end of the 4-month intervention. Sedentary time increased from baseline to 4-months and was sustained until 10-months. The ENCOURAGE intervention did not increase MVPA10Mins over time. However, improvements in other secondary outcomes indicate that a multilevel intervention delivered within primary care may contribute to health behavior changes.

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OBJECTIVE: Excess body weight in children has become a serious public health concern worldwide. The Centers for Disease Control and Prevention (CDC) demonstrated that childhood obesity has tripled since the 1970s in the United States. To prevent childhood obesity, the CDC recommends that children achieve 60 minutes of moderate to vigorous physical activity each day. A variety of wearable monitors are available for objectively assessing activity but these methods are complicated by the lack of established values for the activity intensity and comparability across devices. The purpose of this study is to establish activity intensity cutpoins for the MotionWatch8 (MW8) accelerometer in children by comparison with the gold standard cutpoints established for the Actigraph GT1M accelerometer. MATERIAL/METHODS: 40 children (ages 9-13 years) from Syracuse, NY were enrolled in this study. All participants were required to wear the two different monitors on the dominant wrist as they performed a resting activity (4-minute sitting), a 4-minute slow-paced walk, a 4-minute faster-paced walk, and a 2-minute vigorous running game to mimic the different intensities a child might perform in a free-living environment. Linear regression and receiver operating characteristic (ROC) curves were performed to assess sensitivity and specificity of MW8 intensity cutpoints. RESULT: Mean value for each activity were positively correlated between MW8 and the Actigraph (r=0.85, p<0.001). The optimal cutpoints for differentiating sedentary from light physical activity, light from MVPA, and moderate from vigorous activity were (≤32 counts, ≥ 371.5 counts, and ≥ 859.5 counts per 30 second interval, respectively). CONCLUSION: The MW8 is a simple and objective instrument for measuring physical activity in children. This study provides usable cutoff values for further testing the validity of the MW8 for measuring physical activity patterns among children.

Status is a salient social cue, to the extent that it shapes our attention, judgment, and memory for other people, and it guides our social interactions. While prior work has addressed the traits associated with status, as well as its effects on cognition and behavior, research on the neural mechanisms of status perception is still relatively sparse and predominantly focused on neural activity during explicit status judgments. Further, there is no research looking at the involvement of person-processing networks in status perception, or how we embed status information in our representations of others. In the present study I asked whether person-specific representations in ventral face-processing regions (occipital face area (OFA), fusiform face area (FFA)) as well as more anterior regions (anterior temporal lobe (ATL) and orbitofrontal cortex (OFC)) contain information about a person’s status, and whether regions involved in affective processing and reward (amygdala, ventral striatum) decode status information as well. Participants learned to associate names, career titles, and reputational status information (high versus low ratings) with objects and faces over a two-day training regimen. Object status served as a nonsocial comparison. Trained stimuli were presented in an fMRI experiment, where participants performed a target detection task unrelated to status. MVPA revealed that face and object sensitive regions in the ATLs and lateral OFC decoded face and object status, respectively. These data suggest that regions sensitive to abstract person knowledge and valuation interact during the perception of social status, potentially contributing to the effects of status on social perception. / Psychology

Die Fähigkeit, Zustände in der Außenwelt zu beurteilen und zu kategorisieren, wird unter dem Oberbegriff „perzeptuelles Entscheiden“ zusammengefasst. In der vorliegenden Arbeit wurde funktionelle Magnetresonanztomografie mit multivariater Musteranalyse verbunden, um offene Fragen zur perzeptuellen Entscheidungsfindung zu beantworten. In der ersten Studie (Hebart et al., 2012) wurde gezeigt, dass der visuelle und parietale Kortex eine Repräsentation abstrakter perzeptueller Entscheidungen aufweisen. Im frühen visuellen Kortex steigt die Menge entscheidungsspezifischer Information mit der Menge an verfügbarer visueller Bewegungsinformation, doch der linke posteriore parietale Kortex zeigt einen negativen Zusammenhang. Diese Ergebnisse zeigen, wo im Gehirn abstrakte Entscheidungen repräsentiert werden und deuten darauf hin, dass die gefundenen Hirnregionen unterschiedlich in den Entscheidungsprozess involviert sind, je nach Menge an verfügbarer sensorischer Information. In der zweiten Studie (Hebart et al., submitted) wurde gezeigt, dass sich eine Repräsentation der Entscheidungsvariable (EV) im fronto-parietalen Assoziationskortex finden lässt. Ferner weist die EV im rechten ventrolateralen präfrontalen Kortex (vlPFC) einen spezifischen Zusammenhang mit konfidenzbezogenen Hirnsignalen im ventralen Striatum auf. Die Ergebnisse deuten darauf hin, dass Konfidenz aus der EV im vlPFC berechnet wird. In der dritten Studie (Christophel et al., 2012) wurde gezeigt, dass der Kurzzeitgedächtnisinhalt im visuellen und posterioren parietalen Kortex, nicht jedoch im präfrontalen Kortex repräsentiert wird. Diese Ergebnisse lassen vermuten, dass der Gedächtnisinhalt in denselben Regionen enkodiert wird, die auch perzeptuelle Entscheidungen repräsentieren können. Zusammenfassend geben die hier errungenen Erkenntnisse Aufschluss über den neuronalen Code des perzeptuellen Entscheidens von Menschen und stellen ein vollständigeres Verständnis der zugrundeliegenden Prozesse in Aussicht. / Perceptual decision-making refers to the ability to arrive at categorical judgments about states of the outside world. Here we use functional magnetic resonance imaging and multivariate pattern analysis to identify decision-related brain regions and address a number of open issues in the field of perceptual decision-making. In the first study (Hebart et al., 2012), we demonstrated that perceptual decisions about motion direction are represented in both visual and parietal cortex, even when decoupled from motor plans. While in early visual cortex the amount of information about perceptual choices follows the amount of sensory evidence presented on the screen, the reverse pattern is observed in left posterior parietal cortex. These results reveal the brain regions involved when choices are encoded in an abstract format and suggest that these two brain regions are recruited differently depending on the amount of sensory evidence available. In the second study (Hebart et al., submitted), we show that the perceptual decision variable (DV) is represented throughout fronto-parietal association cortices. The DV in right ventrolateral prefrontal cortex covaries specifically with brain signals in the ventral striatum representing confidence, demonstrating a close link between the two variables. This suggests that confidence is calculated from the perceptual DV encoded in ventrolateral prefrontal cortex. In the third study (Christophel et al., 2012), using a visual short-term memory (VSTM) task, we demonstrate that the content of VSTM is represented in visual cortex and posterior parietal cortex, but not prefrontal cortex. These results constrain theories of VSTM and suggest that the memorized content is stored in regions shown to represent perceptual decisions. Together, these results shed light on the neuronal code underlying perceptual decision-making in humans and offer the prospect for a more complete understanding of these processes.

Die Erforschung der neuronaler Grundlagen des Arbeitsgedächtnisses (WM) fand breite Aufmerksamkeit, konzentrierte sich aber auf die Speicherung sensorischer Inhalte. Beweise für die kurzfristige Aufrechterhaltung abstrakter, verbaler oder kategorischer Informationen sind selten. Ziel dieser Arbeit ist die Untersuchung der neuronalen Repräsentation von WM-Inhalten auf verschiedenen Abstraktionsebenen. Ich stelle hier drei empirische Studien vor, in denen fMRT, multivariate Musteranalyse oder probabilistische Modelle als Hauptmethoden eingesetzt wurden. Die erste Studie identifizierte kortikale Regionen, die den WM-Inhalt eines Skripts behielten. Chinesische Muttersprachler wurden gebeten, sich bekannte chinesische Zeichen zu merken, was die verbale Kodierung stark fördern. Die Ergebnisse zeigten links lateralisierte sprachbezogene Hirnareale als Kandidatenspeicher für verbale Inhalte. Die zweite und dritte Studie zielten darauf ab, die Hypothese zu testen, dass Farbe als eine Kombination aus einer visuellen Repräsentation und einer kategorischen Repräsentation gespeichert wird. Die zweite Studie verwendete ein sensorisches Kodierungsmodell und ein empirisch basiertes kategorisches Kodierungsmodell, um jeweils zwei Quellen neuronaler Repräsentationen zu charakterisieren. Farbinformationen wurden in drei farbbezogenen ROIs dekodiert: V1, V4, VO1, und insbesondere wurde eine Erhöhung der kategorischen Repräsentation in vorderen kortikalen Arealen beobachtet. In der dritten Studie wurde die verzögerte Verhaltensreaktion untersucht, die ein systematisches Bias-Muster zeigte; es wurde ein probabilistisches Dual-Content-Modell implementiert, das ein mit den experimentellen Ergebnissen hoch korreliertes Antwortmuster erzeugte; dies bestätigte die Hypothese der mnemonischen Dual-Content Repräsentation. Diese Studien zusammen schlagen eine Arbeitsteilung entlang der rostro-kaudalen Achse des Gehirns, die auf der Abstraktionsebene der gespeicherten Inhalte basiert. / Research on the neural basis of working memory (WM) has received broad attention but has focused on storage of sensory content. Evidence on short-term maintenance of abstract verbal or categorical information is scarce. This thesis aims to investigate neural representation of WM content at different levels of abstraction. I present here three empirical studies that employed fMRI, multivariate pattern analysis or probabilistic modeling as major methods. The first study identified cortical regions that retained WM content of a script. Native Chinese speakers were asked to memorize well-known Chinese characters which strongly facilitated verbal coding. Results indicated left lateralized language-related brain areas as candidate stores for verbal content. The second and the third studies aimed to test the hypothesis that color is memorized as a combination of the low-level visual representation and the abstract categorical representation. The second study utilized a conventional sensory encoding model and a novel empirical-based categorical encoding model to characterize two sources of neural representations. Color information was decoded in three color-related ROIs: V1, V4, VO1, and notably, an elevation in categorical representation was observed in more anterior cortices. In the third study, the delayed behavioral response was examined, which exhibited a systematic bias pattern; a probabilistic dual-content model was implemented, which produced response patterns highly correlated with experimental results; this confirmed the hypothesis of dual-content mnemonic representations. These studies together suggest a division of labor along the rostral-caudal axis of the brain, based on the abstraction level of memorized contents.

Actions can fail - even though this is well known, little is known about what distinguishes neurophysiological processes preceding errors and correct actions. In this study, relying on the Theory of Event Coding, we test the assumption that only specific aspects of information coded in EEG activity are relevant for understanding processes leading to response errors. We examined N = 69 healthy participants who performed a mental rotation task and combined temporal EEG signal decomposition with multivariate pattern analysis (MVPA) and source localization analyses. We show that fractions of the EEG signal, primarily representing stimulus-response translation (event file) processes and motor response representations, are essential. Stimulus representations were less critical. The source localization results revealed widespread activity modulations in structures including the frontopolar, the middle and superior frontal, the anterior cingulate cortex, the cuneus, the inferior parietal cortex, and the ventral stream regions. These are associated with differential effects of the neural dynamics preceding correct/erroneous responses. The temporal-generalization MVPA showed that event file representations and representations of the motor response were already distinct 200 ms after stimulus presentation and this lasted till around 700 ms. The stability of this representational content was predictive for the magnitude of posterror slowing, which was particularly strong when there was no clear distinction between the neural activity profile of event file representations associated with a correct or an erroneous response. The study provides a detailed analysis of the dynamics leading to an error/correct response in connection to an overarching framework on action control.

An ever-increasing number of functional magnetic resonance imaging (fMRI) studies are now using information-based multi-voxel pattern analysis (MVPA) techniques to decode mental states. In doing so, they achieve a significantly greater sensitivity compared to when they use univariate analysis frameworks. Two most prominent MVPA methods for information mapping are searchlight decoding and classifier weight mapping. The new MVPA brain mapping methods, however, have also posed new challenges for analysis and statistical inference on the group level. In this thesis, I discuss why the usual procedure of performing t-tests on MVPA derived information maps across subjects in order to produce a group statistic is inappropriate. I propose a fully nonparametric solution to this problem, which achieves higher sensitivity than the most commonly used t-based procedure. The proposed method is based on resampling methods and preserves the spatial dependencies in the MVPA-derived information maps. This enables to incorporate a cluster size control for the multiple testing problem. Using a volumetric searchlight decoding procedure and classifier weight maps, I demonstrate the validity and sensitivity of the new approach using both simulated and real fMRI data sets. In comparison to the standard t-test procedure implemented in SPM8, the new results showed a higher sensitivity and spatial specificity. The second goal of this thesis is the comparison of the two widely used information mapping approaches -- the searchlight technique and classifier weight mapping. Both methods take into account the spatially distributed patterns of activation in order to predict stimulus conditions, however the searchlight method solely operates on the local scale. The searchlight decoding technique has furthermore been found to be prone to spatial inaccuracies. For instance, the spatial extent of informative areas is generally exaggerated, and their spatial configuration is distorted. In this thesis, I compare searchlight decoding with linear classifier weight mapping, both using the formerly proposed non-parametric statistical framework using a simulation and ultra-high-field 7T experimental data. It was found that the searchlight method led to spatial inaccuracies that are especially noticeable in high-resolution fMRI data. In contrast, the weight mapping method was more spatially precise, revealing both informative anatomical structures as well as the direction by which voxels contribute to the classification. By maximizing the spatial accuracy of ultra-high-field fMRI results, such global multivariate methods provide a substantial improvement for characterizing structure-function relationships.

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