MVPA

Parietal cortex is often implicated in visual processing of actions. Action understanding is essentially abstract, specific to the type or goal of action, but greatly independent of variations in the perceived position of the action. If certain parietal regions are involved in action understanding, then we expect them to show these generalization and selectivity properties. However, additional functions of parietal cortex, such as self-action control, may impose other demands by requiring an accurate representation of the location of graspable objects. Therefore, the dimensions along which responses are modulated may indicate the functional role of specific parietal regions. Here, we studied the degree of position invariance and hand/object specificity during viewing of tool-grasping actions. To that end, we characterize the information available about location, hand, and tool identity in the patterns of fMRI activation in various cortical areas: early visual cortex, posterior intra...

Previously, multi-voxel pattern analysis has been used to decode words referring to concrete object categories. In this study we investigated if single-trial-based brain activity was sufficient to distinguish abstract (e.g., mercy) versus concrete (e.g., barn) concept representations. Multiple neuroimag-ing studies have identified differences in the processing of abstract versus concrete concepts based on the averaged activity across time by using univariate methods. In this study we used multi-voxel pattern analysis to decode functional magnetic resonance imaging (fMRI) data when participants perform a semantic similarity judgment task on triplets of either abstract or concrete words with similar meanings. Classifiers were trained to identify individual trials as concrete or abstract. Cross-validated accuracies for classifying trials as abstract or concrete were significantly above chance (P < 0.05) for all participants. Discriminating information was distributed in multiple brain regions. Moreover, accuracy of identifying single trial data for any one participant as abstract or concrete was also reliably above chance (P < 0.05) when the classifier was trained solely on data from other participants. These results suggest abstract and concrete concepts differ in representations in terms of neural activity patterns during a short period of time across the whole brain. Hum Brain Mapp 34:1133–1147, 2013. V C 2012 Wiley Periodicals, Inc.

How do our brains achieve the cognitive control that is required
for flexible behavior? Several models of cognitive control
propose a role for frontoparietal cortex in the structure and
representation of task sets or rules. For behavior to be flexible,
however, the system must also rapidly reorganize as mental focus
changes. Here we used multivoxel pattern analysis of fMRI
data to demonstrate adaptive reorganization of frontoparietal
activity patterns following a change in the complexity of the
task rules. When task rules were relatively simple, frontoparietal
cortex did not hold detectable information about these
rules. In contrast, when the rules were more complex, frontoparietal
cortex showed clear and decodable rule discrimination.
Our data demonstrate that frontoparietal activity adjusts to task
complexity, with better discrimination of rules that are behaviorally
more confusable. The change in coding was specific to
the rule element of the task and was not mirrored in more specialized
cortex (early visual cortex) where coding was independent
of difficulty. In line with an adaptive view of frontoparietal
function, the data suggest a system that rapidly reconfigures in
accordance with the difficulty of a behavioral task. This system
may provide a neural basis for the flexible control of human
behavior.

Adaptive coding of stimuli in visual cortex is well documented in perception, where it supports efficient encoding over a broad range of possible percepts. Recently, a similar neural mechanism has been reported also in value-based decision, where it allows optimal encoding of vast ranges of values in PFC: neuronal response to value depends on the choice context (relative coding), rather than being invariant across contexts (absolute coding). Additionally, value learning is sensitive to the amount of feedback information: providing complete feedback (both obtained and forgone outcomes) instead of partial feedback (only obtained outcome) improves learning. However, it is unclear whether relative coding occurs in all PFC regions and how it is affected by feedback information. We systematically investigated univariate and multivariate feedback encoding in various PFC regions and compared three modes of neural coding: absolute, partially-adaptive and fully-adaptive.
Twenty-eight human participants (both sexes) performed a learning task while undergoing fMRI scanning. On each trial, they chose between two symbols associated with a certain outcome. Then, the decision outcome was revealed. Notably, in half of the trials participants received partial feedback, while in the other half they got complete feedback. We used univariate and multivariate analysis to explore value encoding in different feedback conditions.
We found that both obtained and forgone outcomes were encoded in mPFC, but with opposite sign in ventral and dorsal subdivisions. Moreover, we showed that increasing feedback information induced a switch from absolute to relative coding. Our results suggest that complete feedback information promotes context-dependent outcome encoding.

Humans use rules to organize their actions to achieve specific goals. While simple rules that link a sensory stimulus to one response may suffice in some situations, often the application of multiple, hierarchically-organized rules is required. Recent theories suggest that progressively higher level rules are encoded along an anterior-to-posterior gradient within PFC. While some work supports the existence of such a functional gradient, other studies argue for a lesser degree of specialization within PFC. We used fMRI to investigate whether rules at different hierarchical levels are represented at distinct locations in the brain or encoded by a single system. Thirty-seven male and female participants represented and applied hierarchical rule sets containing one lower-level stimulus-response rule and one higher-level selection rule. We used multivariate pattern analysis to directly investigate the representation of rules at each hierarchical level in absence of information about rules from other levels or other task-related information, thus providing a clear identification of low- and high-level rule representations. We could decode low- and high-level rules from local patterns of brain activity within a wide frontoparietal network. However, no significant difference existed between regions encoding representations of rules from both levels, except for precentral gyrus that represented only low-level rule information. Our findings show that the brain represents conditional rules irrespective of their level in the explored hierarchy, and thus that the human control system did not organize task representation according to this dimension. Our paradigm represents a promising approach to identify critical principles that shape this control system.

Neural responses in visual cortex are governed by a topographic mapping from retinal locations to cortical responses. Moreover, at the voxel population level early visual cortex (EVC) activity enables accurate decoding of stimuli locations. However, in many cases information enabling one to discriminate between locations (i.e., discriminative information) may be less relevant than information regarding the relative location of two objects (i.e., relative information). For example, when planning to grab a cup, determining whether the cup is located at the same retinal location as the hand is hardly relevant, whereas the location of the cup relative to the hand is crucial for performing the action. We have previously used multivariate pattern analysis techniques to measure discriminative location information, and found the highest levels in EVC, in line with other studies. Here we show, using representational similarity analysis, that availability of discriminative information in fMRI activation patterns does not entail availability of relative information. Specifically, we find that relative location information can be reliably extracted from activity patterns in posterior intraparietal sulcus (pIPS), but not from EVC, where we find the spatial representation to be warped. We further show that this variability in relative information levels between regions can be explained by a computational model based on an array of receptive fields. Moreover, when the model's receptive fields are extended to include inhibitory surround regions, the model can account for the spatial warping in EVC. These results demonstrate how size and shape properties of receptive fields in human visual cortex contribute to the transformation of discriminative spatial representations into relative spatial representations along the visual stream.

Based on self-determination theory, adolescents’ leisure-time (LT) physical activity (PA) behaviour may depend on the extent by which they perceive an environment as autonomy-supportive. The present study aimed to investigate whether adolescents’ perception of autonomy-supportive behaviour from their peers is related to adolescents’ objectively measured LT moderate-to-vigorous physical activity (MVPA) through perceived psychological needs satisfaction and intrinsic motivation towards PA. School students (n=215) aged between 12 to 15 years old (age: 13.20±0.96 yrs) completed self-reported measures of perceived peers’ autonomy support, psychological needs satisfaction, and intrinsic motivation in the context of LT PA. In addition, study participants wore an accelerometer (Acti-Graph GT3X) to monitor their MVPA. Results of the structural equation modelling revealed that perceived autonomy support from peers had a significant and positive effect on perceptions of all three psychological...

Evidence suggests that physical activity patterns become habitual during childhood, and it is possible that activity patterns continue into adulthood. Unfortunately, traditional physical education practices have been called into question in regard to the amount of vigorous physical activity the class actually provides. Undergraduate physical education teacher education programs provide an opportune setting in which preservice teachers can be introduced to the demand of meeting these unique and challenging goals with less pressure than under the responsibility of teaching full-time without university support. One curriculum model believed to address the concern of facing physical education is Sport Education. The purpose of this study was to determine what impact preservice teachers had on students accruing the recommended levels of moderate to vigorous physical activity (MVPA) during their early field experience of an undergraduate secondary methods course while teaching within the Sport Education curriculum model. Participants were four preservice teachers assigned to teach sport education to middle school students during a secondary methods course field experience. Leeson were filmed and analyzed using a modified version of the System for Observing Fitness Instruction Time and the System for Observing Play and Leisure Activity in Youth. Calculation of overall student activity shows that students were sedentary for 45.19% of the lesson duration, walking for 38.00% of the lesson, and vigorously active for 16.81% of their respective lesson. The discussion section outlines possible reasons for these results, as well as suggestions for physical educators to increase MVPA during Sport Education.

Poster Presentation:
The purpose of this study was to determine what impact preservice teachers had on their pupils accruing the recommended levels of MVPA during their early field experience of a secondary methods course teaching using the Sport Education curriculum model.

Task preparation has traditionally been thought to rely upon persistent representations of instructions that permit their execution after delays. Accumulating evidence suggests, however, that accurate retention of task knowledge can be insufficient for successful performance. Here, we hypothesized that instructed facts would be organized into a task set; a temporary coding scheme that proactively tunes sensorimotor pathways according to instructions to enable highly efficient " reflex-like " performance. We devised a paradigm requiring either implementation or memorization of novel stimulus–response mapping instructions, and used multivoxel pattern analysis of neuroimaging data to compare neural coding of instructions during the pretarget phase. Although participants could retain instructions under both demands, we observed striking differences in their representation. To-be-memorized instructions could only be decoded from mid-occipital and posterior parietal cortices, consistent with previous work on visual short-term memory storage. In contrast, to-be-implemented instructions could also be decoded from frontoparietal " multiple-demand " regions, and dedicated visual areas, implicated in processing instructed stimuli. Neural specificity in the latter moreover correlated with performance speed only when instructions were prepared, likely reflecting the preconfiguration of instructed decision circuits. Together, these data illuminate how the brain proactively optimizes performance, and help dissociate neural mechanisms supporting task control and short-term memory storage.

Humans recognize faces and objects with high speed and accuracy regardless of their orientation. Recent studies have proposed that orientation invariance in face recognition involves an intermediate representation where neural responses are similar for mirror-symmetric views. Here, we used fMRI, multivariate pattern analysis, and computational modeling to investigate the neural encoding of faces and vehicles at different rotational angles. Corroborating previous studies, we demonstrate a representation of face orientation in the fusiform face-selective area (FFA). We go beyond these studies by showing that this representation is category-selective and tolerant to retinal translation. Critically, by controlling for low-level confounds, we found the representation of orientation in FFA to be compatible with a linear angle code. Aspects of mirror-symmetric coding cannot be ruled out when FFA mean activity levels are considered as a dimension of coding. Finally, we used a parametric family of computational models, involving a biased sampling of view-tuned neuronal clusters, to compare different face angle encoding models. The best fitting model exhibited a predominance of neuronal clusters tuned to frontal views of faces. In sum, our findings suggest a category-selective and monotonic code of face orientation in the human FFA, in line with primate electrophysiology studies that observed mirror-symmetric tuning of neural responses at higher stages of the visual system, beyond the putative homolog of human FFA.

Human and non-human primates rely on information gathered from faces during social interaction. Two channels of information are gathered from the face—the identity of the individual (conveyed by featural and configural aspects of the face), as well as their mental state and potential intentions (conveyed by the dynamic face). With respect to identity, humans can recognize thousands of people who are familiar to them very quickly and accurately without effort. Similarly, new individuals can be identified often after only one previous encounter. With respect to the affective/mental states of others, these can be inferred from affective expressions as well as other facial signals such as gaze changes from both strangers and those who are well known to us. That brain injuries can cause selective deficits in the recognition of identity was at the core of a now classic model of face perception proposed by Vicki Bruce and Andy Young in the late 1980s (Bruce and Young, 1986). The original model also postulated a pathway for dealing with facial expressions. Indeed, further work on the affective aspects of face processing was conducted by Andy Calder in collaboration with Andy Young (Calder and Young, 2005). The elements of this model have been given a parallel processing and functional neuroanatomical bent, based on not only patient studies, but on functional neuroimaging investigations showing ventral visual pathway activity in healthy subjects (Haxby et al., 2000). Multivariate classification methods (e.g., MVPA) analyzing fMRI data further indicate that category-specific patches of cortex, such as those observed to faces, may be identified in the ventral visual system (Haxby et al., 2001), consistent with human intracranial neurophysiological studies (Puce et al., 1999). In the current " Research Topic " we have gathered 33 works that include experimental studies, as well as hypothetical and theoretical contributions that review the various behavioral, neurophysiological, and hemodynamic correlates of face processing across the lifespan in both typical and atypical populations. It is our view that future important achievements in the field will likely be derived via interdisciplinary collaborations of scientists coming from different fields, as evidenced by the manuscripts in this volume that include contributions from social and cognitive neuroscientists, cognitive scientists, clinical psychologists, philosophers, as well as engineers, and physicists. Overall, face processing in healthy subjects formed the major corpus of manuscripts in the current " Research Topic. " Prosopagnosia was the main theme of six research studies (see below) and two reviews on strategies to enhance face-processing skills (Bate and Bennetts; DeGutis et al.), thus representing the most investigated condition in this special issue on face processing.