Search results for "FRONTAL CORTEX"
showing 10 items of 355 documents
Segregation of areas related to visual working memory in the prefrontal cortex revealed by rTMS.
2002
The functional organization of working memory (WM) in the human prefrontal cortex remains unclear. Storage and processing functions might be segregated in ventral and dorsal areas of the prefrontal cortex, respectively. If so, storage functions might be spared, irrespective of informational domain, following damage or dysfunction in dorsolateral areas. Alternatively, WM and prefrontal function in general might be segregated according to informational domains (e.g. spatial versus object-based information). In the present study we used repetitive transcranial magnetic stimulation (rTMS) to directly test these competing hypotheses. We applied rTMS to transiently and selectively disrupt the fun…
Chronometry of parietal and prefrontal activations in verbal working memory revealed by transcranial magnetic stimulation.
2003
We explored the temporal dynamics of parietal and prefrontal cortex involvement in verbal working memory employing single-pulse transcranial magnetic stimulation (TMS). In six healthy volunteers the left or right inferior parietal and prefrontal cortex was stimulated with the aid of a frameless stereotactic system. TMS was applied at 10 different time points 140-500 ms into the delay period of a two-back verbal working memory task. A choice reaction task was used as a control task. Interference with task accuracy was induced by TMS earlier in the parietal cortex than in the prefrontal cortex and earlier over the right than the left hemisphere. This suggests a propagation of information flow…
The influence of rTMS over prefrontal and motor areas in a morphological task: grammatical vs. semantic effects
2008
We investigated the differential role of two frontal regions in the processing of grammatical and semantic knowledge. Given the documented specificity of the prefrontal cortex for the grammatical class of verbs, and of the primary motor cortex for the semantic class of action words, we sought to investigate whether the prefrontal cortex is also sensitive to semantic effects, and whether the motor cortex is also sensitive to grammatical class effects. We used repetitive transcranial magnetic stimulation (rTMS) to suppress the excitability of a portion of left prefontal cortex (first experiment) and of the motor area (second experiment). In the first experiment we found that rTMS applied to t…
The what and how of observational learning
2007
Abstract Neuroimaging evidence increasingly supports the hypothesis that the same neural structures subserve the execution, imagination, and observation of actions. We used repetitive transcranial magnetic stimulation (rTMS) to investigate the specific roles of cerebellum and dorsolateral prefrontal cortex (DLPFC) in observational learning of a visuomotor task. Subjects observed an actor detecting a hidden sequence in a matrix and then performed the task detecting either the previously observed sequence or a new one. rTMS applied over the cerebellum before the observational training interfered with performance of the new sequence, whereas rTMS applied over the DLPFC interfered with performa…
The role of the right temporo-parietal junction in social decision-making
2018
Identifying someone else's noncooperative intentions can prevent exploitation in social interactions. Hence, the inference of another person's mental state might be most pronounced in order to improve social decision‐making. Here, we tested the hypothesis that brain regions associated with Theory of Mind (ToM), particularly the right temporo–parietal junction (rTPJ), show higher neural responses when interacting with a selfish person and that the rTPJ‐activity as well as cooperative tendencies will change over time. We used functional magnetic resonance imaging (fMRI) and a modified prisoner's dilemma game in which 20 participants interacted with three fictive playing partners who behaved a…
From Vivaldi to Beatles and back: predicting lateralized brain responses to music.
2013
We aimed at predicting the temporal evolution of brain activity in naturalistic music listening conditions using a combination of neuroimaging and acoustic feature extraction. Participants were scanned using functional Magnetic Resonance Imaging (fMRI) while listening to two musical medleys, including pieces from various genres with and without lyrics. Regression models were built to predict voxel-wise brain activations which were then tested in a cross-validation setting in order to evaluate the robustness of the hence created models across stimuli. To further assess the generalizability of the models we extended the cross-validation procedure by including another dataset, which comprised …
Confabulation: damage to a specific inferior medial prefrontal system
2008
Confabulation, the pathological production of false memories, occurs following a variety of aetiologies involving the frontal lobes, and is frequently held to be underpinned by combined memory and executive deficits. However, the critical frontal regions and specific cognitive deficits involved are unclear. Studies in amnesic patients have associated confabulation with damage to the orbital and ventromedial prefrontal cortices. However, neuroimaging studies have associated memory-control processes which are assumed to underlie confabulation with the right lateral prefrontal cortex. We used a confabulation battery to investigate the occurrence and localisation of confabulation in an unselect…
'Prefrontal' cognitive performance of healthy subjects positively correlates with cerebral FDOPA influx: an exploratory [18F]-fluoro-L-DOPA-PET inves…
2006
Dopamine neurotransmission influences those cognitive processes, which are generally regarded as prefrontal cortical functions. In previous positron‐emission‐tomography (PET) studies, net blood‐brain clearance of [(18)F]‐fluoro‐l‐DOPA (FDOPA) correlated with impaired cognitive performance in patients with Parkinson's disease or schizophrenia. We hypothesized that FDOPA influx also correlates with performance of cognitive tasks associated with prefrontal functioning in healthy volunteers. The net blood‐brain clearance of FDOPA (K [Formula: see text]) was mapped in a group of 11 healthy volunteers and calculated in striatal volumes‐of‐interest. The Wisconsin‐Card‐Sorting‐Test (WCST), Stroop‐T…
Emotional reactivity in chronic schizophrenia: structural and functional brain correlates and the influence of adverse childhood experiences
2011
Background. Despite behavioural signs of flattened affect, patients affected by schizophrenia show enhanced sensitivity to negative stimuli. The current literature concerning neural circuitry for emotions supports dysregulations of cortico-limbic networks, but gives contrasting results. Adverse childhood experiences (ACEs) could persistently influence emotional regulation and neural correlates of response to emotional stimuli in healthy humans. This study evaluated the effect of ACEs and chronic undifferentiated schizophrenia on neural responses to emotional stimuli (negative facial expression). Method. Brain blood-oxygen-level-dependent functional magnetic resonance imaging neural response…
Age-related differences in the neural correlates of remembering time-based intentions.
2012
The present study used event-related potentials (ERPs) to explore the effect of age on the neural correlates of monitoring processes involved in time-based prospective memory.In both younger and older adults, the addition of a time-based prospective memory task to an ongoing task led to a sustained ERP activity broadly distributed over the scalp. Older adults, however, did not exhibit the slow wave activity observed in younger adults over prefrontal regions, which is considered to be associated with retrieval mode. This finding indicates that age-related decline in intention maintenance might be one source of the impaired prospective memory performance displayed by older adults. An 'anterio…