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Intracerebral paragangliomas are tumors with a low incidence. Only 13 cases have been reported in the literature to date. This type of tumor shows characteristic histopathological features but unclear histogenesis. Owing to its low incidence, little knowledge exists concerning the best therapeutic strategy. We report on a 55-year-old male patient with the diagnosis of a paraganglioma of the cerebellum. We compare our patient's case to similar cases reported in the literature, describe the typical course of the disease, and discuss therapeutic options. No relapse of disease was observed in our patient within 2 years of diagnosis. Surgery and adjuvant conventionally fractionated external beam radiotherapy seem to be well tolerated and feasible. A review of patients reported in the literature and a comparison to our patient reveals a good prognosis for intracerebral paragangliomas. The optimal therapeutic strategy with regard to the benefit of adjuvant radiotherapy after total or subtotal resection has yet to be defined.

Much research on visual functions in migraine has pinpointed the existence of abnormal visual processing between attacks. However, it is not clear if this is due to cortical hyper- or hypoexcitability. We aimed to clarify this issue by comparing motion perception thresholds of subjects with migraine with (MA) or without aura (MoA) and control subjects. Two types of dot kinetograms were used: in the first experiment coherently moving dots were presented in an incoherent environment, while in the second only coherent motion was seen. Subjects with migraine displayed significantly impaired motion perception compared with controls when they had to detect the direction of the coherently moving dots in an incoherent environment, while they were slightly better in a direction discrimination task, where only coherent motion was presented. This pattern of results is comparable to those achieved by an external excitability enhancement of V5 induced in healthy human subjects in a former study of our group. According to this, a cortical excitability enhancement can result in an impaired focusing on a given signal against a noisy background, but improves perception of non-ambiguous stimuli. Thus we conclude that migraineurs display enhanced visual cortical excitability between attacks in V5.

Previous studies have claimed that weak transcranial direct current stimulation (tDCS) induces persisting excitability changes in the human motor cortex that can be more pronounced than cortical modulation induced by transcranial magnetic stimulation, but there are no studies that have evaluated the effects of tDCS on working memory. Our aim was to determine whether anodal transcranial direct current stimulation, which enhances brain cortical excitability and activity, would modify performance in a sequential-letter working memory task when administered to the dorsolateral prefrontal cortex (DLPFC). Fifteen subjects underwent a three-back working memory task based on letters. This task was performed during sham and anodal stimulation applied over the left DLPFC. Moreover seven of these subjects performed the same task, but with inverse polarity (cathodal stimulation of the left DLPFC) and anodal stimulation of the primary motor cortex (M1). Our results indicate that only anodal stimulation of the left prefrontal cortex, but not cathodal stimulation of left DLPFC or anodal stimulation of M1, increases the accuracy of the task performance when compared to sham stimulation of the same area. This accuracy enhancement during active stimulation cannot be accounted for by slowed responses, as response times were not changed by stimulation. Our results indicate that left prefrontal anodal stimulation leads to an enhancement of working memory performance. Furthermore, this effect depends on the stimulation polarity and is specific to the site of stimulation. This result may be helpful to develop future interventions aiming at clinical benefits.

Background and Purpose: Up to 10% of all neck lymph node metastases present without a known primary site. The optimal treatment strategy for these patients is still undefined. The purpose of this retrospective analysis is to assess the outcome in patients with neck metastases from an unknown primary tumor (CUP). Furthermore, prognostic factors and treatment modalities are discussed., Patients and Methods: From 1984 to 2003, 28 patients with squamous cell neck metastases from a CUP were treated at the authors' institution. In 17 patients, neck dissection (twelve radical, five modified radical) was performed. In that case, adjuvant radiotherapy was carried out with a mean of 56.7 Gy. In eleven patients, only biopsies were done. These patients received definitive radiotherapy with a mean of 66.8 Gy. In summary, 25 patients received extended radiotherapy including both sides of the neck and potential mucosal primary sites. Additional chemotherapy was administered to five patients., Results: The duration of follow-up was 4.1-189.5 months (median 45.1 months). After this period of time, ten patients (36%) remained alive. 5-year overall survival was 40.1%, neck control rate 72.7%. No subsequent primary could be detected. Extracapsular extension and surgery had significant influence on prognosis. Grade 3 toxicity (mucositis or skin reactions) was seen in three patients; no hematologic toxicity > grade 2 was observed. 19 patients suffered from grade 2 xerostomia., Conclusion: With radical surgery followed by radiotherapy good survival rates in patients with neck metastases from a CUP can be obtained. Whether limited radiotherapy might be equal to extended irradiation and can reduce side effects, must be shown in ongoing clinical trials.

Objective: To determine whether weak transcranial direct current stimulation (tDCS), which is an interesting new tool inducing prolonged cortical excitability shifts in humans, induces brain edema, disturbance of the blood-brain barrier or structural alterations of the brain detectable by magnetic resonance imaging (MRI)., Methods: In 10 healthy individuals, tDCS, which is known to alter cortical excitability for about 1 h, was applied over motor and pre-frontal cortices. contrast-enhanced t1-, t2-, and diffusion-weighted mri was performed immediately before, 30 and 60 min after tdcs., Results: MRI performed 30 and 60 min after tDCS did not show pathological signal alterations in pre- and post-contrast-enhanced T1-weighted and diffusion-weighted MR sequences., Conclusions: tDCS protocols which are known to result in cortical excitability changes persisting for an hour after stimulation do not induce brain edema or alterations of the blood-brain barrier or cerebral tissue detectable by MRI., Significance: These results deliver further evidence for the safety of the currently applied tDCS protocols in humans.

Background: The purpose of this study was to evaluate the efficacy and toxicity of radiotherapy and concomitant 5-fluorouracil (5-FU) and mitomycin-C infusion in inoperable head and neck cancer., Methods: Seventy-six patients (86% men, 14% women), mean age 57 years, with primary inoperable head and neck cancer were treated with 70 Gy plus simultaneous intravenous chemotherapy with 5-FU (600 mg/m(2)/d, days 1 to 5) and mitomycin-C (10 mg/m(2), day 5 plus 36)., Results: After a mean follow-up of 13 months, 31 patients were alive. Complete response (CR) was seen in 63%. The 1- and 2-year overall survival rates were 67.7% and 39.5%, and locoregional control rates were 51.7% and 35.6%. Pretreatment hemoglobin <13.9 g/dL was associated with lower locoregional control rates (p = .03). Therapy was well tolerated (grade 3 mucositis in 21%, grade 4 in 1%, grade 3 leukopenia in 11%)., Conclusions: Our radiochemotherapy regimen offers a curative option for this group of patients with a poor prognosis. Hemoglobin levels before therapy have an influence on prognosis., ((c) 2004 Wiley Periodicals, Inc.)

Weak transcranial direct current stimulation (tDCS) can induce long lasting changes in cortical excitability. In the present study we asked whether tDCS applied to the left primary motor cortex (M1) also produces aftereffects distant from the site of the stimulating electrodes. We therefore tested corticospinal excitability in the left and the right M1 and transcallosal excitability between the two cortices using transcranial magnetic stimulation (TMS) before and after applying tDCS. Eight healthy subjects received 10 min of anodal or cathodal tDCS (1 mA) to the left M1. We examined the amplitude of contralateral motor evoked potentials (MEPs) and the onset latency and duration of transcallosal inhibition with single pulse TMS. MEPs evoked from the tDCS stimulated (left) M1 were increased by 32% after anodal and decreased by 27% after cathodal tDCS, while transcallosal inhibition evoked from the left M1 remained unchanged. The effect on MEPs evoked from the left M1 lasted longer for cathodal than for anodal tDCS. MEPs evoked from the right M1 were unchanged whilst the duration of transcallosal inhibition evoked from the right M1 was shortened after cathodal tDCS and prolonged after anodal tDCS. The duration of transcallosal inhibition returned to control values before the effect on the MEPs from the left M1 had recovered. These findings are compatible with the idea that tDCS-induced aftereffects in the cortical motor system are limited to the stimulated hemisphere, and that tDCS not only affects corticospinal circuits involved in producing MEPs but also inhibitory interneurons mediating transcallosal inhibition from the contralateral hemisphere.

Modulation of cerebral excitability is thought to be one mechanism underlying the pharmacological treatment of neuropsychiatric diseases such as epilepsy, depression, and dystonia. Repetitive transcranial magnetic stimulation (rTMS) has been tested for several years as a nonpharmacological, noninvasive method of directly influencing patients' cortical functions. We present an overview of the more easily performed transcranial direct current stimulation (tDCS) with weak current, which produces distinctly more pronounced changes in excitability than rTMS. The basic underlying mechanism is a shift in the resting membrane potential towards either hyper- or depolarisation, depending on stimulation polarity. This in turn leads to changes in the excitability of cortical neurons. Anodic stimulation increases cortical excitability, while cathodic stimulation decreases it. These changes persist after the end of stimulation if the stimulation lasts long enough, i.e., at least several minutes. The duration of this aftereffect can be controlled through the duration and intensity of the stimulation. Transcranial direct current stimulation essentially allows a focal, selective, reversible, pain-free, and noninvasive induction of changes in cortical excitability, the therapeutic potential of which must be evaluated in clinical studies, once possible risk factors have been assessed.

The mammalian primary olfactory system consists of a set of different telencephalic structures, including paleo-, archi-, periarchi- and mesocortical components. We present the first characterisation of the normal and connectional anatomy of the primary olfactory cortex of the common marmoset, a microsmatic simian species increasingly used in primate research. The centrifugal and centripetal bulbar projections were determined by injections of the anterograde and retrograde tracer wheat germ agglutinin-conjugated horseradish peroxidase and fluorescent dyes into the ipsilateral main olfactory bulb. The efferent projections of the marmoset bulb are organised entirely ipsilaterally and are established via a rudimentary medial olfactory tract and the dominant lateral olfactory tract. Target areas are the anterior olfactory nucleus, the entire prepiriform cortex, ventral tenia tecta, periamygdaloid cortex and the rostral part of the entorhinal cortex. The bulbar axons predominantly terminate in the outer part of layer I. The anterior olfactory nucleus receives a weak additional input within layer II and III, which is not found in macrosmatic rodents. Further anterograde labelling was found in the endopiriform nucleus deep under the prepiriform cortex and within an anterolateral strip of the olfactory tubercle. However, control injections into the olfactory tubercle suggest that the marmoset olfactory tubercle receives a bisynaptic olfactory input only. Retrograde labelling after bulb injections revealed that, except for the olfactory tubercle, all primary olfactory cortices contributed to an ipsilateral bulbopetal feedback projection. Like in rodents, the only bulbopetal projection organised bilaterally in the marmoset is maintained by the anterior olfactory nucleus. With few exceptions, the projections of the marmoset olfactory brain are organised similarly to that of the macaque monkey or those of macrosmatic species., (Copyright 2002 S. Karger AG, Basel)

Static and dynamic contrast sensitivities (sCS and dCS) were evaluated before, during, immediately after and 10 min after anodal and cathodal transcranial direct current stimulation (tDCS) applied to the occipital cortex of 15 healthy subjects. Using 4 c/d spatial and 4 Hz temporal frequencies significant sCS and dCS loss was found during and immediately after 7 min cathodal stimulation while anodal stimulation had no effect. Ten minutes after the end of the stimulation the sCS and dCS values had reached the baseline levels. Our results show that primary visual functions, such as contrast detection can be transiently altered by transcranial weak direct current stimulation, most probably modulating neural excitability, as has been shown in the motor cortex previously. The present study also support the view that this method using weak current can be a non-invasive promising tool to induce reversible focal changes in the nervous system.

Blood oxygenation level dependent (BOLD) MRI was used to monitor modulations of human sensorimotor activity by prior transcranial direct current stimulation (tDCS). Activation maps for a right hand sequential finger opposition task were obtained for six subjects before as well as 0-5 min and 15-20 min after a 5-min period of 1 mA cathodal and, in a separate session, anodal tDCS of the left-hemispheric motor cortex. Cathodal tDCS resulted in a global decrease of the mean number of activated pixels by 38% (P < 0.01) 0-5 min after stimulation, which reduced to 28% (P < 0.05) 15-20 min after stimulation. A region-of-interest analysis revealed a 57% decrease of activated pixels (P < 0.001) in the supplementary motor area, but no change in the hand area of the primary motor cortex. Anodal tDCS yielded a nonsignificant 5% increase of activated pixels with no regional differences. These findings support the view that reduced neuroaxonal excitability after cathodal tDCS causes reduced brain activity. However, rather than affecting the primary sensorimotor input of an active task, the process appears to dampen those responses that rely on cortico-cortical connections and related processing. Magn Reson Med 45:196-201, 2001., (Copyright 2001 Wiley-Liss, Inc.)