Scoring System Assessing Risks of Growth in Sporadic Vestibular Schwannoma.

Background And Objectives: Surveillance studies offer sparse knowledge of predictors of future growth in sporadic vestibular schwannomas (VS).Our aim was identification of these risk factors. We propose a scoring system to estimate the risk of growth in sporadic vestibular schwannoma.

Long-term oncological outcomes after haemorrhagic apoplexy in pituitary adenoma managed operatively and non-operatively.

Introduction: Depending on severity of presentation, pituitary apoplexy can be managed with acute surgery or non-operatively. We aim to assess long-term tumour control, visual and endocrinological outcomes following pituitary apoplexy with special emphasis on patients treated non-operatively.

Methods: Multicentre retrospective cohort study.

Facial Nerve Function Outcome and Risk Factors in Resection of Large Cystic Vestibular Schwannomas.

 Cystic vestibular schwannomas (VS) in contrast to solid VS tend to have accelerated growth, larger volume, rapid/atypical presentation, lobulated/adherent surface, and unpredictable course of the cranial nerves. Cystic VS are surgically challenging, with worse clinical outcomes and higher rate of subtotal resection (STR).  We retrospectively analyzed postoperative outcomes of 125 patients with cystic VS, operated between years 2005 and 2019 in our center.

Shunt Testing In Vivo: Illustration of Partially Obstructed Ventricular Catheter by In-Growing Choroid Plexus.

Assessing shunt function in vivo presents a diagnostic challenge. Infusion studies can be a cost-effective and minimally invasive aid in the assessment of shunt function in vivo. We describe a case of a patient who after a foramen magnum decompression for type I Chiari malformation developed bilateral posterior fossa subdural hygromas and mild hydrocephalus, eventually necessitating insertion of a ventriculoperitoneal shunt.

White matter pathways associated with working memory in normal aging.

Introduction: Previous studies by our group have found that white matter integrity as determined by Diffusion Tensor Imaging (DTI) is associated with working memory decline. It has been proposed that subtle white matter integrity loss may lead to the disruption of working memory in particular because it relies on the dynamic and reiterative activity of cortico-cortical pathways.

Methods: DTI and working memory measurement were acquired for 99 adults from our GENIE study of healthy middle aged and elderly individuals.

White matter tract visualization using properties of termination coordinate eigenmaps.

We present a fast and informative technique for determining colors that differentiate white matter pathways generated by deterministic diffusion tensor tractography (DTT) based on streamline termination coordinate (TC) locations in native space. In particular, terminations coordinates are mapped to a standard stereotactic space and colors are generated using a fast eigenmapping approach designed to provide a single eigenvector representing both TCs. This eigenvector is then colored by mapping the vector x-coordinate to the red channel, the y-coordinate to the green channel, and the z-coordinate to the blue channel.

Atlas-based segmentation of white matter tracts of the human brain using diffusion tensor tractography and comparison with classical dissection.

The technique of diffusion tensor tractography is gaining increasing prominence as a non-invasive method for studying the architecture of the white matter pathways in the human brain. Numerous studies have been published that attempt to identify or reconstruct particular pathways of interest. An atlas or map of all the pathways in the white matter would be particularly useful for providing detailed anatomical data that is not available in studies based on conventional MRI data.

White matter pathway asymmetry underlies functional lateralization.

Structural and functional asymmetry of the human brain has been well documented using techniques such as magnetic resonance imaging (MRI). However, asymmetry of underlying white matter connections is less well understood. We applied an MRI technique known as diffusion tensor tractography to reveal the morphology of the white matter in vivo by mapping directions of maximum water diffusion in brain tissue.

The origin of the vomiting response: a neuroanatomical hypothesis.

The connections of area postrema include a set of nuclei with a common topographical location immediately deep to the ependyma or pia mater. These nuclei are all within two principal synapses of the area postrema and can be reached by more than one route from it. There is direct evidence that, like the area postrema, a number of these nuclei participate in vomiting.

Effects of partial truncal vagotomy on intragastric pressure responses to vagal stimulation and gastric distension in ferrets.

Changes in intragastric pressure after dorsal truncal vagotomy, investigated by stimulation of the surviving vagal branches and by step inflation of the stomach, were divided into an early phase lasting five days, and a late phase continuing for at least three months. During the early phase the amplitude of vagal evoked contraction was diminished but the resting pressure and the response to gastric inflation were increased. After the fifth day vagal evoked contractions doubled in amplitude but the resting pressure and the response to step inflation of the stomach returned to control levels.

Variation of the ferret skull (Mustela putorius furo L.) in relation to stereotaxic landmarks.

The ferret skull was investigated to identify reliable extracranial landmarks for stereotaxy. The skulls of 56 ferrets of both sexes were measured in a stereotaxic apparatus. Neither body weight nor an index of skull length proved to be reliable predictors of intracranial location.

Quantification of branched neuronal projections labelled by retrograde fluorescent tracing. A study of olivo-cerebellar projections.

A method for estimating the number of branched and unbranched neurones projecting from a nucleus to two target sites is presented, based on the retrograde transport of fluorescent tracers. The method initially involves stereological corrections for the size of cytoplasm and nuclei respectively labelled by the two tracers. A second correction is applied to account for doubly labelled cells whose cytoplasm, but not nuclei, are in the plane of section.

Gastric tone modifies the responses to extrinsic neural stimuli in the anaesthetized ferret.

To determine the relation between resting intragastric pressure and neuronally evoked motility responses, the stomach of the anaesthetized ferret was inflated with two volumes within the physiological range. Vagal evoked contractions decreased as the resting pressure was increased. The decrease affected responses to high, but not low, intensity stimulation of the vagus.

Quantitative analysis of the topographical organization of olivocerebellar projections in the rat.

The inferior olivary projection to anterior and posterior regions of the cerebellar vermis was studied in the rat using the retrograde fluorescent double-labelling technique in combination with a computerized data collection system. A technique for quantifying and statistically analysing the point-to-point (or nucleotopic) organization of the projection is presented. It was found that one group of neurones in the medial accessory olivary nucleus projected to cerebellar lobules 6 or 7, and second group projected to lobules 4 or 5, while a third sent collaterals to both areas.

Characteristics of the vagally driven non-adrenergic, non-cholinergic inhibitory innervation of ferret gastric corpus.

This paper reports a quantitative in vivo study on the vagal activation of the intramural non-adrenergic, non-cholinergic inhibitory nerves in the ferret gastric corpus. The nature of the inhibitory neurotransmitter was also investigated. In the atropinized, guanethidine-treated, urethane-anaesthetized ferret, electrical stimulation (10 s at 20 V, 1-20 Hz, 0.

Interactions between splanchnic and vagus nerves in the control of mean intragastric pressure in the ferret.

To determine whether splanchnic nerves relax the stomach by direct or indirect mechanisms, ramp inflations of the stomach, section and electrical stimulation of the vagus and greater splanchnic nerves, and step inflations of the duodenum were used. A high threshold, sustained inhibition of the gastric pressure response to ramp inflation was mediated by the vagus. Prior splanchnectomy increased vagal inhibition.

Variation between different samples of SITS with respect to axonal transport and toxicity.

Retrograde axonal transport of the fluorescent compound SITS has been described as occurring only from axon terminals and not from axons of passage. Injection of 4 different commercially available samples of SITS into terminations of cerebellar pathways in the rat revealed that only one sample produced retrogradely labelled neurones. Chemical analysis suggested that this was due to a unique fluorescent component (not SITS).

The role of vagal and intramural inhibitory reflexes in the regulation of intragastric pressure in the ferret.

1. The step inflation technique combined with nerve section and pharmacological receptor blockade was used to determine the gastric distribution of the vagal inhibitory fibres and their role in the regulation of intragastric pressure in the anaesthetized ferret.2.

Peripheral functional organisation of vagally evoked gastric motor responses in the ferret.

The aims of the present study were to determine the relative amplitudes of intragastric motor responses evoked by different vagal branches and to establish whether the effects of acute or chronic vagotomy could be predicted from these data. Intragastric pressure responses to electrical stimulation of the vagus were measured in urethane-anaesthetised ferrets and acute or chronic vagotomies were performed. The results show that the left and right cervical vagi were equipotential and fully overlaped each other.

The role of the vagus and splanchnic nerves in the regulation of intragastric pressure in the ferret.

1. The role of the vagus and splanchnic nerves in the regulation of intragastric pressure was investigated by quantifying the effect of nerve section on the response to a standard fluid inflation of the stomach. An opportunity was also taken to compare the responses to a step and physiological ramp inflation of the same volume (50 ml).

The clinical reliability of brain stem auditory evoked responses.

Auditory evoked responses thought to originate in the brain stem were investigated in patients with and without good evidence of brain stem pathology, and in healthy volunteers. The purpose of the investigation was to find a method of quantifying these evoked responses which would be clinically useful. The best quantitative measure was the latencies of certain peaks in the evoked response considered in combination.