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Single-pulse transcranial magnetic stimulation reveals contribution of premotor cortex to object shape recognition
No full textAction Contro
Action Recognition in Context
No full textAs humans, our everyday life is inherently social. To interact in a world shaped by social
interaction, it is crucial to recognise and understand other agent’s actions. While
action recognition is widely studied in psychology and cognitive neuroscience, contextual
information, for instance the scene an action is embedded in, is often left out.
There is promising evidence underlining the importance of context and its congruency
on action recognition. The neuronal correlates of this context influence on action recognition
are, however, not clear yet. To test action recognition in context, we designed
a novel task in which first an indoor scence context image alone is presented, and then
motion-captured action videos are superimposed on the image followed by a forcedchoice
task. We tested the new paradigm first behaviourally (N=25), and then used
functional Magnetic Resonance Imaging (fMRI) to investigate brain activation while
participants performed the task. The behavioural results show a context-congruency
effects in recognition accuracy, with significant effects of incongruent-congruent and
incongruent-neutral context settings on action recognition. For the fMRI part we at
present have a sample of N=8 participants, which makes the statistical tests intended
impossible. Design, analysis pipeline and expectations of this fMRI paradigm with decoding
techniques are still discussed in the present thesis
How action selection can be embodied: intracranial gamma band recording shows response competition during the Eriksen flankers test
No full textRecent findings in monkeys suggest that action selection is based on a competition between various action options that are automatically planned by the motor system. Here we discuss data from intracranial EEG recordings in human premotor cortex during a bimanual version of the Eriksen flankers test that suggest that the same principles apply to human action decisions. Recording sites in the dorsal premotor cortex show an early but undifferentiated activation, a delayed response that depends on the experimental conditions and, finally, a movement related activation during action execution. Additionally, we found that the medial part of the premotor cortex show a significant increase in response for ipsilateral trials, suggesting a role in inhibiting the wrong response. The ventral premotor cortex seems to be involved in action execution, rather than action selection. Together these findings suggest that the human premotor cortex is part of a network that specifies, selects, and executes actions
Nowhere and Everywhere: The Causal Origin of Voluntary Action
No full textThe idea that intentions make the difference between voluntary and non-voluntary behaviors is simple and intuitive. At the same time, we lack an understanding of how voluntary actions actually come about, and the unquestioned appeal to intentions as discrete causes of actions offers little if anything in the way of an answer. We cite evidence suggesting that the origin of actions varies depending on context and effector, and argue that actions emerge from a causal web in the brain, rather than a central origin of intentional action. We argue that this causal web need not be confined to the central nervous system, and that proprioceptive feedback might play a counterintuitive role in the decision process. Finally we argue that the complex and dynamic origins of voluntary action and their interplay with the brain’s propensity to predict the immediate future are better studied using a dynamical systems approach.LNCONational Licence
Nowhere and Everywhere: The Causal Origin of Voluntary Action
Get PDFThe idea that intentions make the difference between voluntary and non-voluntary behaviors is simple and intuitive. At the same time, we lack an understanding of how voluntary actions actually come about, and the unquestioned appeal to intentions as discrete causes of actions offers little if anything in the way of an answer. We cite evidence suggesting that the origin of actions varies depending on context and effector, and argue that actions emerge from a causal web in the brain, rather than a central origin of intentional action. We argue that this causal web need not be confined to the central nervous system, and that proprioceptive feedback might play a counterintuitive role in the decision process. Finally we argue that the complex and dynamic origins of voluntary action and their interplay with the brain's propensity to predict the immediate future are better studied using a dynamical systems approach
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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