Search results for " Transcranial"
showing 10 items of 110 documents
Prefrontal and temporo-parietal involvement in taking others' perspective: TMS evidence.
2008
INTRODUCTION: Understanding the mental states of others entails a number of cognitive processes known as Theory of Mind (ToM). Behavioural and functional neuroimaging evidence suggests that prefrontal and temporo-parietal cortices are involved in these abilities. The present study was aimed at investigating the role of the dorsolateral prefrontal cortex and temporo-parietal junction in ToM by using a repetitive transcranial magnetic stimulation (rTMS) paradigm. MATERIAL AND METHODS: Eleven healthy subjects participated in the study. The experimental ToM procedure was constituted by false belief and faux-pas written stories. Subjects were evaluated in baseline condition (Sham) and after 1Hz …
Recognition memory and prefrontal cortex: Dissociating recollection and familiarity processes using rTMS
2008
Recognition memory can be supported by both the assessment of the familiarity of an item and by the recollection of the context in which an item was encountered. The neural substrates of these memory processes are controversial. To address these issues we applied repetitive transcranial magnetic stimulation (rTMS) over the right and left dorsolateral prefrontal cortex (DLPFC) of healthy subjects performing a remember/know task. rTMS disrupted familiarity judgments when applied before encoding of stimuli over both right and left DLPFC. rTMS disrupted recollection when applied before encoding of stimuli over the right DLPFC. These findings suggest that the DLPFC plays a critical role in recog…
The effect of paired associative stimulation on fatigue resistance
2015
Paired associative stimulation (PAS) is a non-invasive stimulation method developed to induce bidirectional changes in the excitability of the cortical projections to the target muscles. However, very few studies have shown an association between changes in motor evoked potentials (MEP) after PAS and behavioral changes in healthy subjects. In the present study we hypothesized that the functional relevance of PAS can be seen during fatiguing exercise, since there is always a central contribution to the development of fatigue. Transcranial magnetic stimulation was applied over the motor cortex to measure changes in the MEPs of the soleus muscle before and after PAS. Furthermore, fatigue resis…
Ictal functional TCD for the lateralization of the seizure onset zone—a report of two cases
2004
Ictal functional transcranial Doppler sonography (I-fTCD) was used to lateralize the ictal onset zone in the presurgical evaluation of two patients with temporal lobe epilepsy. In one patient, I-fTCD and ictal SPECT were performed simultaneously during EEG-monitoring. In both patients, results were concordant with the ictal SPECT findings, PET and semiology. I-fTCD seems to be an interesting new method to non-invasively lateralize the seizure onset zone with high temporal resolution. I-fTCD and SPECT may give complementary information to lateralize the seizure onset zone.
Transcranial Doppler ultrasonography in the assessment of cerebral circulation arrest: improving sensitivity by trancervical and transorbital carotid…
2009
INTRODUCTION: Transcranial Doppler (TCD) can detect the cerebral circulation arrest (CCA) in brain death. TCD is highly specific, but less sensitive because of false-negatives accounting for up to 10%. The aim of the study was to explore the diagnostic accuracy of TCD and to determine whether it can be augmented by strategies such as the insonation of the extracranial internal carotid artery (ICA) and sequential examinations. METHODS: Data of 184 patients, who met clinical criteria of brain death, observed from 1998 through 2006, were retrospectively reviewed. The study of cerebral arteries was performed through the transtemporal approach, suboccipital insonation of the vertebro-basilar sys…
Involvement of Jugular Valve Insufficiency in Cerebral Venous Air Embolism
2007
Background. Cerebral venous air entrapment is a rare finding on cranial computed tomography (CT) scan. Peripheral air embolism is discussed as a potential cause. However, the mechanism of retrograde passage through internal jugular valves and veins is unclear. Case Report. The case of a patient is reported, who had air entrapment in the left cavernous sinus. Prior to CT scanning, a peripheral intravenous line had been placed. Ultrasound revealed excessive insufficiency of the left internal jugular valve. To further study the mechanism of embolism, an echo contrast agent was injected into the cubital vein. A Valsalva maneuver resulted in retrograde transition of microbubbles across the insuf…
Intravenous recombinant erythropoietin does not lead to an increase in cerebrospinal fluid erythropoietin concentration
2000
No abstract
Transcranial doppler and near infrared spectroscopy in the perioperative period
2013
Maintenance of adequate blood flow and oxygen to the brain is one of the principal endpoints of all surgery and anesthesia. During operations in general anesthesia, however, the brain is at particular risk for silent ischemia. Despite this risk, the brain still remains one of the last monitored organs in clincial anesthesiology.Transcranial Doppler (TCD) sonography and near-infrared spectroscopy (NIRS) experience a revival as these noninvasive technologies help to detect silent cerebral ischemia. TCD allows for quantification of blood flow velocities in basal intracranial arteries. TCD-derived variables such as the pulsatility index might hint toward diminished cognitive reserve or raised i…
Ultrasonography for evaluation of the carotid artery in head and neck cancer.
1994
The dynamic relationship of lymph node metastases to surrounding vascular structures in the neck is important for preoperative patient assessment. When carotid artery involvement is suspected, this relationship often determines whether or not to operate. In the case of adhesive neck metastases along the internal jugular vein, it becomes possible to predict preoperatively if the integrity of this vein may be preserved. Ultrasonography has the ability to differentiate subtle from gross adherence, or simple compression from vascular invasion. This is done by manually palpating the tumor mass and asking the patient to perform various maneuvers while observing on a monitor the relationship of th…
The role of transcranial magnetic stimulation in the study of cerebellar cognitive function.
2007
Transcranial magnetic stimulation (TMS) allows non-invasive stimulation of brain structures. This technique can be used either for stimulating the motor cortex, recording motor evoked potentials from peripheral muscles, or for modulating the excitability of other non-motor areas in order to establish their necessity for a given task. TMS of the cerebellum can give interesting insights on the cerebellar functions. Paired-TMS techniques, delivering stimuli over the cerebellum followed at various interstimulus intervals by stimuli over the motor cortex, allow studying the pattern of connectivity between the cerebellum and the contralateral motor cortex in physiological as well as in pathologic…