Search results for "NEUROSCIENCE"
showing 10 items of 8040 documents
Disentangling common and specific neural subprocesses of response inhibition.
2012
article i nfo Response inhibition is disturbed in several disorders sharing impulse control deficits as a core symptom. Since response inhibition is a cognitively and neurally multifaceted function which has been shown to rely on differing neural subprocesses and neurotransmitter systems, further differentiation to define neurophys- iological endophenotypes is essential. Response inhibition may involve at least three separable cognitive sub- components, i.e. interference inhibition, action withholding, and action cancelation. Here, we introduce a novel paradigm - the Hybrid Response Inhibition task - to disentangle interference inhibition, action withholding and action cancelation and their…
Meaningful physical changes mediate lexical-semantic integration: top-down and form-based bottom-up information sources interact in the N400
2011
Models of how the human brain reconstructs an intended meaning from a linguistic input often draw upon the N400 event-related potential (ERP) component as evidence. Current accounts of the N400 emphasise either the role of contextually induced lexical preactivation of a critical word (Lau, Phillips,& Poeppel, 2008) or the ease of integration into the overall discourse context including a wide variety of influencing factors (Hagoort & van Berkum, 2007). The present ERP study challenges both types of accounts by demonstrating a contextually independent and purely form-based bottom-up influence on the N400: the N400 effect for implausible sentence-endings was attenuated when the critical sente…
Cognitive control after distraction: event-related brain potentials (ERPs) dissociate between different processes of attentional allocation.
2008
Attentional reallocation after a distracting event is an important function of cognitive control. This process is tapped by the reorienting negativity (RON) event-related brain potential. It was argued that the RON reflects orientation of attention to relevant information in working memory. To test this hypothesis participants performed an auditory duration discrimination task. The stimuli were presented in a frequent standard or a rare deviant pitch with deviants resulting in behavioral distraction. Participants accomplished this task under two conditions: In the refocus condition participants were asked to respond to every stimulus; in the reorient condition participants were instructed t…
Does the left inferior parietal lobule contribute to multiplication facts?
2005
We report a single case, who presents with a selective and severe impairment for multiplication and division facts. His ability to retrieve subtraction and addition facts was entirely normal. His brain lesion affected the left superior temporal and to lesser extent in the left middle temporal gyri and the left precentral gyrus extending inferiorly to the pars opercularis of the left frontal lobe. Interestingly, the left supramarginal and angular gyri (SMG/AG) were spared. This finding realised a double dissociation with a previously reported patient, who despite lesions in the SMG/AG did not have a multiplication impairment (van Harskamp et al., 2002). The previously suggested crucial role …
Neuroanatomical basis of number synaesthesias: A voxel-based morphometry study
2016
In synaesthesia, a specific sensory dimension leads to an involuntary sensation in another sensory dimension not commonly associated with it; for example, synaesthetes may experience a specific colour when listening or thinking of numbers or letters. Large-scale behavioural studies provide a rich description of different synaesthesia phenotypes, and a great amount of research has been oriented to uncovering whether a single or multiple brain mechanisms underlie these various synaesthesia phenotypes. Interestingly, most of the synaesthetic inducers are conceptual stimuli such as numbers, letters, and months. However, the impact of these concepts on the synaesthetic brain remains largely unex…
Bodily self-relatedness in vicarious touch is reflected at early cortical processing stages.
2019
Studies have suggested that there is a strong link between the bodily self and the mechanisms underlying vicarious representations. Here, we used somatosensory ERPs to investigate the temporal dynamics of vicarious touch for stimuli that are more or less related to one's own body (human hands vs. rubber gloves). We found that vicarious touch effects were restricted to self-relatable events (human hands) at early implicit stages of somatosensory processing (P45). At later more cognitive stages of processing (late positive complex, LPC), the vicarious touch effect was stronger for self-relatable events (touch on human hands) than nonself-relatable events (touch on rubber gloves) but present f…
The Neural Correlates of Grammatical Gender: An fMRI Investigation
2002
Abstract In an fMRI experiment, subjects saw a written noun and made three distinct decisions in separate sessions: Is its grammatical gender masculine or feminine (grammatical feature task)? Is it an animal or an artifact (semantic task)? Does it contain a /tch/ or a /k/ sound (phonological task)? Relative to the other experimental conditions, the grammatical feature task activated areas of the left middle and inferior frontal gyrus and of the left middle and inferior temporal gyrus. These activations fit in well with neuropsychological studies that document the correlation between left frontal lesions and damage to morphological processes in agrammatism, and the correlation between left t…
Numbers and time doubly dissociate
2011
The magnitude dimensions of number, time and space have been suggested to share some common magnitude processing, which may imply symmetric interaction among dimensions. Here we challenge these suggestions by presenting a double dissociation between two neuropsychological patients with left (JT) and right (CB) parietal lesions and selective impairment of number and time processing respectively. Both patients showed an influence of task-irrelevant number stimuli on time but not space processing. In JT otherwise preserved time processing was severely impaired in the mere presence of task-irrelevant numbers, which themselves could not be processed accurately. In CB, impaired temporal estimatio…
Task relevance and recognition of concealed information have different influences on electrodermal activity and event-related brain potentials.
2009
This study aimed at differentiating between memory- and task-related processes and their correlates on the electrodermal and electrocortical level during information concealment. Variations of the Guilty Knowledge Test were implemented in two experiments while we measured skin conductance responses (SCRs) and event-related brain potentials. P300 amplitudes were specifically enhanced for items requiring a deviant behavioral response but they were not sensitive to concealed knowledge. In contrast, N200 amplitudes differed between memorized and irrelevant items in both experiments. SCR measures reflected a combined influence of task relevance and probe recognition, and they provided incrementa…
Why Do Forward Maskers Affect Auditory Intensity Discrimination? Evidence from "Molecular Psychophysics"
2014
Nonsimultaneous maskers can strongly impair performance in an auditory intensity discrimination task. Using methods of molecular psychophysics, we quantified the extent to which (1) a masker-induced impairment of the representation of target intensity (i.e., increase in internal noise) and (2) a systematic influence of the masker intensities on the decision variable contribute to these effects. In a two-interval intensity discrimination procedure, targets were presented in quiet, and combined with forward maskers. The lateralization of the maskers relative to the targets was varied via the interaural time difference. Intensity difference limens (DLs) were strongly elevated under forward mas…