The processing of lexical ambiguity in healthy ageing and Parkinson׳s disease: role of cortico-subcortical networks.

Previous neuroimaging studies showed that correct resolution of lexical ambiguity relies on the integrity of prefrontal and inferior parietal cortices. Whereas prefrontal brain areas were associated with executive control over semantic selection, inferior parietal areas were linked with access to modality-independent representations of semantic memory. Yet insufficiently understood is the contribution of subcortical structures in ambiguity processing.

Evaluation of spatial processing in virtual reality using functional magnetic resonance imaging (FMRI).

While the ecological validity of virtual reality (VR) applications is usually assessed by behavioral data or interrogation, an alternative approach on a neuronal level is offered by brain imaging methods. Because it is yet unclear if 3D space in virtual environments is processed analogically to the real world, we conducted a study investigating virtual spatial processing in the brain using functional magnetic resonance imaging (fMRI). Results show differences in VR spatial brain processing as compared to known brain activations in reality.

Cerebral activations resulting from virtual dental treatment.

Pain, and anxiety of pain, for some people are serious problems in dental treatment. It is a common practical experience that even entering a dental surgery office, or the sound of a dental drill, may evoke vegetative correlates of toothache without any underlying disease. This everyday phenomenon suggests the hypothesis of a corresponding activation of pain-related brain areas by virtual dental treatment.

Long-term depression of pain-related cerebral activation in healthy man: an fMRI study.

Electrical low-frequency stimulation (LFS) of cutaneous afferents reliably induces long-term depression (LTD) of nociception and pain in man. In this study LFS effects on cerebral activation were investigated by functional magnetic resonance imaging (fMRI). In 17 healthy volunteers, nociceptive fibers of right hand dorsum were electrically stimulated via a concentric electrode.

Feasibility of k-t BLAST for BOLD fMRI with a spin-echo based acquisition at 3 T and 7 T.

Objectives: This study tested the feasibility of applying k-t BLAST to blood oxygen level dependent functional MRI of the brain at 3 Tesla (T) and at 7 T. Shorter echo train lengths, achieved through the application of k-t BLAST, are expected to counteract increased sensitivity to inhomogeneities in B0 at higher magnetic field strengths, especially in echo planar images, and reduce the relatively long acquisition times and high RF power deposition in spin-echo based methods.

Materials And Methods: k-t BLAST was combined with displaced UFLARE at 3 T and 7 T.

Estradiol modulates functional brain organization during the menstrual cycle: an analysis of interhemispheric inhibition.

According to the hypothesis of progesterone-mediated interhemispheric decoupling (Hausmann and Güntürkün, 2000), functional cerebral asymmetries (FCAs), which are stable in men and change during the menstrual cycle in women, are generated by interhemispheric inhibition of the dominant on the nondominant hemisphere. The change of lateralization during the menstrual cycle in women might indicate that sex hormones play an important role in modulating FCAs. We used functional magnetic resonance imaging to examine the role of estradiol in determining cyclic changes of interhemispheric inhibition.

The neurofunctional mechanisms of traumatic and non-traumatic memory in patients with acute PTSD following accident trauma.

Neurofunctional alterations in acute posttraumatic stress disorder (PTSD) and changes thereof during the course of the disease are not well investigated. We used functional magnetic resonance imaging to assess the functional neuroanatomy of emotional memory in surgical patients with acute PTSD. Traumatic (relative to non-traumatic) memories increased neural activity in the amygdala, hippocampus, lateral temporal, retrosplenial, and anterior cingulate cortices.

The subcortical role of language processing. High level linguistic features such as ambiguity-resolution and the human brain; an fMRI study.

In the present study, we were interested in the neurofunctional representations of ambiguity processing by using functional magnetic resonance imaging (fMRI). Twelve right-handed, healthy adults aged between 21 and 29 years (6 male, 6 female) underwent an ambiguity resolution task with 4 different conditions (dominant vs. non-dominant; dominant vs.

Neural correlates of primary and reflective consciousness of spatial orienting.

Using functional magnetic resonance imaging, we asked participants to perform a visual target detection task with peripheral cues. In the first part of the experiment, cues were not predictive of the side of occurrence of the incoming target. In the second part of the experiment, unbeknownst to the participants, cues became 80% predictive, thus inducing an endogenous orienting of spatial attention.

Management of attentional resources in within-modal and cross-modal divided attention tasks: an fMRI study.

In the present study, we were interested in distinguishing the cortical representations of within-modal and cross-modal divided attention tasks by using functional magnetic resonance imaging. Sixteen healthy male subjects aged between 21 and 30 years underwent two within-modal (auditory/auditory, visual/visual) and one cross-modal (auditory/visual) divided attention task, as well as related selective attention control conditions. After subtraction of the corresponding control task the three divided attention tasks, irrespective of sensory modality, revealed significant activation in a predominantly right hemisphere network involving the prefrontal cortex, the inferior parietal cortex, and the claustrum.

A special role for numbers in working memory? An fMRI study.

Although numbers carry averbal semantics (i.e., magnitude), they are often utilized in verbal Working Memory (vWM) tasks.

Functional reorganisation in patients with right hemisphere stroke after training of alertness: a longitudinal PET and fMRI study in eight cases.

In patients with alertness deficits due to right hemispheric vascular brain damage, training induced changes in the individual functional networks involved in intrinsic alertness were assessed in a longitudinal positron emission tomography (PET)/fMRI activation study. Patients were trained by administering the alertness routine of the AIXTENT computerized attention training or, in the control condition, by using a computerized training of verbal and topological memory. Before and after the training, both a PET/fMRI and a neuropsychological assessment were carried out.

Neural processing of traumatic events in subjects suffering PTSD - a case study of two surgical patients with severe accident trauma.

Neuroimaging research on the neurobiology of chronic PTSD (posttraumatic stress disorder) has revealed structural and functional alterations primarily affecting areas of the medial temporal lobe (hippocampus, amygdala, and parahippocampal gyrus) and the frontal cortex known to be associated with the disorder. Using functional magnetic resonance imaging (fMRI), the present study studied the functional neuroanatomy of traumatic and non-traumatic emotional memory in two surgical patients who had sustained severe accident trauma. While patient 1 had developed acute PTSD following the traumatic event, patient 2 (control) did not.