Dirk Bernhardt-Walther

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We propose a five-layer hierarchical space-time model (HSTM) for representing and searching human actions in videos. From a feature point of view, both invariance and selectivity are desirable characteristics, which seem to contradict each other. To make these characteristics coexist, we introduce a coarse-to-fine search and verification scheme based on the(More)
In this study, we present a new method for establishing fMRI pattern-based functional connectivity between brain regions by estimating their multivariate mutual information. Recent advances in the numerical approximation of highdimensional probability distributions allow us to successfully estimate mutual information from scarce fMRI data. We also show that(More)
The human brain can be described as containing a number of functional regions. These regions, as well as the connections between them, play a key role in information processing in the brain. However, most existing multi-voxel pattern analysis approaches either treat multiple regions as one large uniform region or several independent regions, ignoring the(More)
Humans efficiently grasp complex visual environments, making highly consistent judgments of entry-level category despite their high variability in visual appearance. How does the human brain arrive at the invariant neural representations underlying categorization of real-world environments? We here show that the neural representation of visual environments(More)
Many data analysis problems in neuroimaging are set up as classification problems, frequently involving multiple classes. Typically, only the fraction of correct classifications is reported as aggregate accuracy. However, the structure of the classification errors contains valuable information as well. By reinterpreting confusion matrices as conditional(More)
Auditory salience describes how much a particular auditory event attracts human attention. Previous attempts at automatic detection of salient audio events have been hampered by the challenge of defining ground truth. In this paper ground truth for auditory salience is built up from annotations by human subjects of a large corpus of meeting room recordings.(More)
Visual neuroscience is a field of great specialization, where submodalities such as motion, depth, form and color are often studied in isolation. One disadvantage of this isolation is that results from each subfield are not integrated to constrain common underlying neural circuitry. Yet, to deeply understand the cortical computations underlying visual(More)
Visual categorization and learning of visual categories exhibit early onset, however the underlying mechanisms of early categorization are not well understood. The main limiting factor for examining these mechanisms is the limited duration of infant cooperation (10-15 minutes), which leaves little room for multiple test trials. With its tight link to visual(More)
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