Barry T., Takano K., Boddez Y., Raes F. (2018). Lower sleep duration is associated with reduced autobiographical memory specificity. Behavioral Sleep Medicine, in press.
Meulders A., Boddez Y., Blanco F., Van Den Houte M., Vlaeyen J. (2018). Reduced selective learning in fibromyalgia patients versus healthy controls. Pain.
Scheveneels, S., Boddez, Y., & Hermans, D. (accepted for publication). Learning mechanisms in fear and anxiety: It is still not what you think it is. In B. Olatunji (Ed.). The Cambridge Handbook of Anxiety and Related Disorders.
Bardi, L., Bundt, C., Notebaert, W. & Brass, M. (2015). Eliminating mirror responses via instructions. Cortex, 70, 128-136.
The observation of an action leads to the activation of the corresponding motor plan in the observer. This phenomenon of motor resonance has an important role in social interaction, promoting imitation, learning and action understanding. However, mirror responses not always have a positive impact on our behavior. An automatic tendency to imitate others can introduce interference in action execution and non-imitative or opposite responses have an advantage in some contexts. Previous studies suggest that mirror tendencies can be suppressed after extensive practice or in complementary joint action situations revealing that mirror responses are more flexible than previously thought. The aim of the present study was to gain insight into the mechanisms that allow response flexibility of motor mirroring. Here we show that the mere instruction of a counter-imitative mapping changes mirror responses as indexed by motor evoked potentials (MEPs) enhancement induced by transcranial magnetic stimulation (TMS). Importantly, mirror activation was measured while participants were passively watching finger movements, without having the opportunity to execute the task. This result suggests that the implementation of task instructions activates stimulus-response association that can overwrite the mirror representations. Our outcome reveals one of the crucial mechanisms that might allow flexible adjustments of mirror responses in different contexts. The implications of this outcome are discussed.
Bundt, C., Bardi, L., Abrahamse, E. L., Brass, M., & Notebaert, W. (2015). It wasn’t me! Motor activation from irrelevant spatial information in the absence of a response. Frontiers in Human Neuroscience, 9, (539).
Embodied cognition postulates that perceptual and motor processes serve higher-order cognitive faculties like language. A major challenge for embodied cognition concerns the grounding of abstract concepts. Here we zoom in on abstract spatial concepts and ask the question to what extent the sensorimotor system is involved in processing these. Most of the empirical support in favor of an embodied perspective on (abstract) spatial information has derived from so-called compatibility effects in which a task-irrelevant feature either facilitates (for compatible trials) or hinders (in incompatible trials) responding to the task-relevant feature. This type of effect has been interpreted in terms of (task-irrelevant) feature-induced response activation. The problem with such approach is that incompatible features generate an array of task-relevant and -irrelevant activations [e.g., in primary motor cortex (M1)], and lateral hemispheric interactions render it difficult to assign credit to the task-irrelevant feature per se in driving these activations. Here, we aim to obtain a cleaner indication of response activation on the basis of abstract spatial information. We employed transcranial magnetic stimulation (TMS) to probe response activation of effectors in response to semantic, task-irrelevant stimuli (i.e., the words left and right) that did not require an overt response. Results revealed larger motor evoked potentials (MEPs) for the right (left) index finger when the word right (left) was presented. Our findings provide support for the grounding of abstract spatial concepts in the sensorimotor system.
Rigoni, D., Pourtois, G., & Brass, M. (2014). 'Why should I care?' Challenging free will attenuates neural reaction to errors. Social Cognitive and Affective Neuroscience, 10, 262-268.
Whether human beings have free will or not has been a philosophical question for centuries. The debate about free will has recently entered the public arena through mass media and newspaper articles commenting on scientific findings that leave little to no room for free will. Previous research has shown that encouraging such a deterministic perspective influences behavior, namely by promoting cursory and antisocial behavior. Here we propose that such behavioral changes may, at least partly, stem from a more basic neurocognitive process related to response monitoring, namely a reduced error detection mechanism. Our results show that the Error-Related Negativity, a neural marker of error detection, was reduced in individuals led to disbelieve in free will. This finding shows that reducing the belief in free will has a specific impact on error detection mechanisms. More generally, it suggests that abstract beliefs about intentional control can influence basic and automatic processes related to action control.
Muhle-Karbe, P.S., Duncan, J., De Baene, W., Mitchell, D.J., & Brass, M. (2016). Neural Coding for Instruction-Based Task Sets in Human Frontoparietal and Visual Cortex. Cerebral Cortex.
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.
Chetail, F. & Content, A. What Is the Difference Between OASIS and OPERA? Roughly Five Pixels: Orthographic Structure Biases the Perceived Length of Letter Strings. Psychological Science, 25 (1), 243-249.
A thorough understanding of monosyllabic-word-recognition processes, in contrast with multisyllabic-word processing, has accumulated over the past decades. One fundamental challenge regarding multisyllabic words concerns their parsing into smaller units and the nature of the cues determining the parsing. We propose that the organization of consonant and vowel letters provides powerful cues for parsing, and we present data from a new task showing that a word’s orthographic structure, as determined by the number of vowel-letter clusters, influences estimations of its length. Words were briefly presented on a computer screen, and participants had to estimate word length by drawing a line on the screen with the mouse. In three experiments, participants estimated words comprising fewer orthographic units as shorter than words comprising more units even though the words matched for number of letters. Further results demonstrated that the length bias was driven by orthographic information and not by phonological structure.
Teuchies, M., Demanet, J., Sidarus, N., Haggard, P., Stevens, M. A., & Brass, M. (2016). Influences of Unconscious Priming on Voluntary actions: role of the Rostral Cingulate Zone. Neuroimage, 135, 243–252.
The ability to make voluntary, free choices is fundamental to what it means to be human. A key brain region that is involved in free choices is the rostral cingulate zone (RCZ), which is part of the medial frontal cortex. Previous research has shown that activity in this brain region can be modulated by bottom-up information while making free choices. The current study extends those findings, and shows, for the first time, that activation in the RCZ can also be modulated by subliminal information. We used a subliminal response priming paradigm to bias free and cued choices. We observed more activation in the RCZ when participants made a choice that went against the prime’s suggestion, compared to when they chose according to the prime. This shows that the RCZ plays an important role in overcoming externally-triggered conflict between different response options, even when the stimuli triggering this conflict are not consciously perceived. Our results suggest that an important mechanism of endogenous action in the RCZ may therefore involve exerting an internally-generated action choice against conflicting influences, such as external sensory evidence. We further found that subliminal information also modulated activity in the anterior insula and the supramarginal gyrus.
