Search results for "Crania"
showing 10 items of 885 documents
The role of posterior parietal cortices on prismatic adaptation effects on the representation of time intervals
2013
Previous studies provided evidence of an ascending left-to-right spatial representation of time durations by using a technique affecting high levels of spatial cognition, i.e. prismatic adaptation (PA). Indeed, PA that induced a leftward aftereffect distorted time representation toward an underestimation, while PA that induced a rightward aftereffect distorted time representation toward an overestimation. The present study advances previous findings on the effects of PA on time by investigating the neural basis subtending these effects. We focused on the posterior parietal cortex (PPC) since it is involved in the PA procedure and also in the formulation of the spatial representation of time…
Influence of Delay Period Duration on Inhibitory Processes for Response Preparation.
2015
In this study, we examined the dynamics of inhibitory preparatory processes, using a delayed response task in which a cue signaled a left or right index finger (Experiment 1) or hand (Experiment 2) movement in advance of an imperative signal. In Experiment 1, we varied the duration of the delay period (200, 500, and 900 ms). When transcranial magnetic stimulation (TMS) was applied 100 ms before the imperative, motor evoked potentials (MEPs) elicited in the first dorsal interosseous were strongly inhibited. For delays of 500 ms or longer, this inhibition was greater when the targeted muscle was selected compared with when it was not selected. In contrast, the magnitude of inhibition just aft…
Changes in corticospinal excitability during an acute bout of resistance exercise in the elbow flexors
2014
Purpose Hypertrophic resistance exercise (HRE) induces central and peripheral fatigue. However, more detailed information about changes in corticospinal excitability remains to be elucidated. Methods Eleven volunteers participated in the upper arm HRE which included one repetition maximum (1 RM) control contractions and three sets of 13 RM (SET1–3). Transcranial magnetic stimulation (TMS) was applied during maximal isometric voluntary contraction (MVC) at the end of each set and during control contractions to study changes in corticospinal excitability. Electrical stimulation was used in order to measure peripheral changes. Results MVC decreased after each set when compared to control contr…
Radiosurgery as Treatment for Acoustic Neuroma. Ten Years’ Experience
2013
The acoustic neuroma is a benign tumour that usually affects the vestibular portion of the vestibulocochlear nerve. It represents 8% of all intracranial tumours and 80% of those arising at the cerebellopontine angle. There are 3 treatment options: microsurgery (the technique of choice), radiosurgery and observation. The objective of the study was to evaluate the results and side effects obtained using radiosurgery as treatment for acoustic neuroma.We performed a review of all patients treated with radiosurgery (Gamma Knife and linear accelerator) at doses of 1200-1300 cGy for unilateral acoustic neuroma in our hospital from January 1999 until January 2010. In all patients we evaluated the o…
Inter- and intra-individual variability of paired-pulse curves with transcranial magnetic stimulation (TMS).
2002
Objectives: Previous studies have evaluated the variability of motor thresholds (MTs) and amplitude of motor-evoked potentials (MEPs) to transcranial magnetic stimulation (TMS) within and across individuals. Here we evaluate the reproducibility and inter-hemispheric variability of measures of cortical excitability using the 'conventional' paired-pulse (PP) TMS technique. Methods: We studied PP curves of the left and right hemisphere in 10 healthy subjects on two separate days 2 weeks apart. The inter-stimulus intervals studied were 1, 3, 6, 8, 10 and 12 ms with the conditioning stimulus being 80% of the resting MT, and a single test stimulus producing MEPs of approximately 0.8 mV peak-to-pe…
Neglect-like effects induced by tDCS modulation of posterior parietal cortices in healthy subjects
2011
Background Repetitive transcranial magnetic stimulation (rTMS) over right posterior parietal cortex was shown to induce interference on visuospatial perception in healthy subjects. Transcranial direct current stimulation (tDCS) is another noninvasive brain stimulation technique that works modulating cortical activity. It is applied through easy to use, noncostly, and portable devices. Objective/Hypothesis The aim of the current study was to investigate if the novel approach of “dual” stimulation over parietal cortices compared with the unilateral (right) cathodal one is able to induce greater and/or longer-lasting neglect-like effects in normal subjects performing a computerized visuospatia…
Lateralized effect of rapid-rate transcranial magnetic stimulation of the prefrontal cortex on mood.
1996
We studied the effects of rapid-rate transcranial magnetic stimulation (rTMS) of different scalp positions on mood Ten normal volunteers rated themselves before and after rTMS on five analog scales labeled ``Tristeza99 (Sadness), ``Ansiedad99 (Anxiety), ``Alegria99 (Happiness), ``Cansancio99 (Tiredness), and ``Dolor/Malestar99 (Pain/Discomfort). rTMS was applied to the right lateral prefrontal, left prefrontal, or midline frontal cortex in trains of 5 seconds9 duration at 10 Hz and 110% of the subject9s motor threshold intensity. Each stimulation position received 10 trains separated by a 25-second pause. No clinically apparent mood changes were evoked by rTMS to any of the scalp positions …
Stereotactic fractionated irradiation of optic nerve sheath meningioma: a new treatment alternative
2002
Background: Primary optic nerve sheath meningioma (ONSM) is a rare but almost invariably blinding tumour when its natural history is observed in a “wait and see” strategy. Surgery has hitherto only been advocated in case of progressive disease involving intracranial structures, as it leads to iatrogenic blindness in the overwhelming majority of cases. Therefore, treatment options bearing lesser risk of functional deterioration are highly desirable, both in cases of intracranial involvement as well as during earlier phases of the disease which are currently generally left untreated. The authors report the outcome of the largest series of patients to date treated by stereotactic fractionated …
The risk of abducens palsy after diagnostic lumbar puncture.
2000
Abducens palsy occasionally has been observed after diagnostic lumbar puncture (DLP).1-3 Its risk is not exactly known. We are aware of only one report, which mentions not a single case among 1,341 DLPs when using 22-gauge needles.4 At our clinic, an average of 800 inpatients a year undergo DLP. We usually use 22-gauge needles, and occasionally (in less than 5%), 20-gauge needles. Over a 14.5-year period, we saw two patients with abducens palsy—one unilateral, one bilateral—after DLP. This translates to a risk of less than 1 out of 5,800 DLPs. ### Patient 1. A 61-year-old man with type 2 diabetes noticed progressive weakness of the legs. Neurologic examination revealed proximal paraparesis,…
Interest of targeting either cortical area Brodmann 9 or 46 in rTMS treatment for depression: a preliminary randomized study.
2013
Abstract Objective To assess the interest of specifically targeting Brodmann Areas (BA) 9 or 46 for rTMS treatment of depression. Methods Patients with Treatment-Resistant Depression were randomly assigned to two treatment groups to receive either rTMS on BA 9 or on BA 46. Each patient underwent 10 sessions of 1Hz-rTMS for 2weeks. The Hamilton and Montgomery–Asberg Depression Rating Scales (HDRS, MADRS) were used under blind conditions to assess the therapeutic response (50% improvement). A Wilcoxon signed-rank test was used to compare the depression rating scales scores obtained before and after the 10 rTMS sessions for each of the two groups. The therapeutic results in the two groups were…