bluuebunny/crossref_metadata_2025 huggingface dataset:
Present Role of Stereotactic Thalamotomy for Parkinsonism
Authors: Miyamoto T. , Bekku H. , Moriyama E. , Tsuchida S.
Published: March 2007

14 cases of unilateral and 5 cases of bilateral thalamotomy for parkinsonism were reviewed, with 32–144 months’ (mean 67.8) and 54–212 months’ (mean 110) follow-up, respectively, after the initial operation. Rigidity and tremor disappeared in approximately 80% of cases and was reduced in the remaining 20%. 68% improved by one or two grades in the Hoehn-Yahr scale after operation. Thalamotomy abolished dyskinesias and on-off phenomena on the operated sides. 36% of cases discontinued levodopa therapy after operation. CT study of the lesions suggested that destruction of a large part of basal Vop was most important to obtain the best results.
Idiopathic Oromandibular Dyskinesia Treated by Vo Complex Microstereotactic Thalamotomy
Authors: Narabayashi H. , Yokochi F. , Nakajima Y.
Published: March 2007

Two cases of oromandibular or buccolingual dyskinesia, which did not respond to medical therapy, had lesions produced in the Vo complex of the thalamus by microstereotactic surgery with almost complete relief of symptoms. It was assumed the symptom, as well as levodopa-induced dyskinesia, may depend on the striato-pallido-thalamic projection.
Cell Sparse Zones in the Ventrolateral Thalamic Mass in Humans, Monkeys and Cats: Their Special Reference to Kinesthetic Neurons
Authors: Hirai T. , Nagaseki Y. , Wada H. , Shibazaki T. , Matsumura M. , Ohye C.
Published: March 2007

The Vim nucleus of the human thalamus is the cell sparse zone. The neurons in this zone respond to peripheral stimuli of kinesthetic modality with a short latency. In the cytometrical study, the cell sparse zone is identifiable in both the monkey and cat thalamus. The cell dimension and density in a 1 mm2 area in the cell sparse zone of each species are as follows: humans – large neuron 500–900 µm2, medium neuron 200–400 µm2, cell density 60–90/mm2/50 µm thickness; monkeys – large neuron 400–800 µm2, medium neuron 200–400 µm2, cell density 120–250/mm2/50 µm thickness; cats – large neuron 400–800 µm2, medium neuron 200–400 µm2, cell density 120–250/mm2/50 µm thickness. In this zone, there are large and medium thalamocortical relay neurons defined by the Golgi impregnated and HRP studies. It is still obscure which neurons respond to kinesthetic stimulation and which neurons or afferent fibers play important roles in the tremor mechanism.
Bipolar Spinal Cord Stimulation for Spasmodic Torticollis
Authors: Dieckmann G. , Veras G.
Published: March 2007

Four years’ experience with electrical stimulation of the cervical cord is reported for 18 patients suffering from spasmodic torticollis. Permanent 1,100-Hz stimulation of the C2–C4 level resulted in a marked improvement in 50% of the patients, in a satisfactory result in 27.8% and in an unsatisfactory result in 22.2%. Muscular tension and related pain were reduced within 8 days to 4 months postoperatively. A measurable improvement of head posture rendered objective by a mechanoelectrical measuring device could only be observed after a continuous stimulation over 8–12 months. The procedure is nondestructive and reversible, complications consisted only in those related to the stimulation system itself.
Preliminary Report on the Use of Fetal Tissue Transplantation to Correct MPTP-Induced Parkinson-Like Syndrome in Primates
Authors: Bakay Roy A.E. , Fiandaca Massimo S. , Barrow Daniel L. , Schiff Arthur , Collins Delwood C.
Published: March 2007

A Parkinson-like syndrome was produced in nonhuman primates and successfully reversed through transplantation of heterologous fetal mesencephalic brain tissue., Rigidity and bradykinesia were induced by the chronic administration of N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. Once the deficits were fixed, Macaca mulatta with well-developed Parkinson-like behavior received fetal mesencephalic cell preparations stereotactically implanted into multiple sites of the head of the caudate bilaterally. Both animals demonstrated a normalization of CSF L-dopa and significant improvement in observed activity. The neuropathological studies performed 2 months following transplantation demonstrated successful integration of fetal cells in the caudate.
Changes in Cerebral Blood Flow after Stereotactic Thalamotomy
Authors: Kullberg Gunvor , Risberg Jarl
Published: March 2007

Regional cerebral blood flow (rCBF), a parameter of neuronal activity in the brain, was measured by the 133Xe inhalation method in 43 patients undergoing stereotactic thalamotomy. A postoperative flow reduction of about 2% in the operated hemisphere was found, persisting in further measurements performed after a year. There was no consistent change in the pattern of regional flow distribution. The results indicate a diminished level of activity in the hemisphere subjected to thalamotomy, but the change could not be linked to any specific area or function.
Influence of Spinal Cord Stimulation on Peripheral Blood Flow
Authors: Broseta J. , Garcia-March G. , Sanchez M.J. , Gonçales J.
Published: March 2007

In 27 vasculopathic and 9 nonvasculopathic patients who underwent spinal cord stimulation to treat pain in lower extremities, Doppler recordings and thermography were used to study peripheral blood flow changes during stimulation. Generally, poststimulation pain relief coincided with a improvement of Doppler recording, an normalization of morphology and increase of pulse wave amplitude, and a rise of skin temperature in the painful area.
Electrical Stimulation of the Cervical Spinal Cord Increases Cerebral Blood Flow in Humans
Authors: Hosobuchi Yoshio
Published: March 2007

Ten patients were studied to determine the effect of spinal cord stimulation on CBF. In 5 patients using a cervical spinal cord stimulator, the stimulation produced a significant increase in CBF in the hemisphere ipsilateral to the induced paresthesia. Thoracic cord stimulation, used by the other 5 patients, had no effect on CBF. Atropine had no effect on the alteration in CBF produced by cervical cord stimulation. Indomethacin, however, partially blocked the effect. These heuristic observations may have implications for the future treatment of cerebrovascular insufficiency in humans.
Complications in Cases of Epidural Stimulation Electrode Implants
Authors: Sogabe K. , Dieckmann G. , Veras G.
Published: March 2007

Spinal cord stimulation (SCS) is an effective treatment for pain and motor disturbances. We have performed 124 SCS procedures between 1981 and 1984 at the University of Göttingen. Reoperations were required for 69 cases (56%) for various reasons, most frequently changes in electrode position due to the dislodgement (36 cases, 52%.) Analysis of the development of this postoperative repositioning showed that 67% occurred within 1 month after the implantation. Therefore, if patients can be kept at rest during the granulation period of 1 month after operation, we suggest that the frequency of reoperation may be considerably lessend.
Indications for Implanted Electrostimulation of the Spinal Cord
Authors: Dooley D.M. , Karaboyas J.
Published: March 2007

Patients with varying complaints of pain and abnormal neurological findings may be suitable candidates for electrical stimulation of the spinal cord. They can be divided into patients with pain and those with arterial disease, movement disorders and neurogenic bladder.
Missing Pieces in the Epilepsy Puzzle
Authors: Ward Jr. Arthur A.
Published: March 2007

Research regarding the basic mechanisms of the epilepsies has been limited and has generated few clues that have led to dramatic improvements in the surgical therapy of epilepsy. It is now known that the epileptic focus is characterized by a population of pacemaker neurons that fire autonomously in bursts. When this high frequency discharge recruits bursting activity in neighboring neurons, a propagating seizure occurs. Such data as well as other recent data in neurobiology indicate that new forms of surgical therapy may be forthcoming including brain transplantation as well as local application of transmitter compounds which may significantly improve the therapy of epilepsy.
Radiosurgical Treatment of Epilepsy
Authors: Salorio Barcia , Roldan P. , Hernandez G. , Gomez L. Lopez
Published: March 2007

Focal irradiation of epileptic foci has been performed in a group of 6 epileptic patients, of whom 2 presented with epilepsy and 4 with epileptic psychoses. The epileptic focus was localized by means of conventional scalp EEG, electrocorticography and stereoelectroencephalography. Radiosurgery was performed by coupling a stereoguide to a 60Co unit using a 10-mm diameter collimator. An estimated dose of 10 Gy was administered. Results are presented and the mechanism of action of radiation discussed.
Foramen Ovale Electrodes: A New Technique Enabling Presurgical Evaluation of Patients with Mesiobasal Temporal Lobe Seizures
Authors: Siegfried J. , Wieser H.G. , Stodieck S.R.R.
Published: March 2007

A recently developed technique to record from the mesiobasal aspect of the temporal lobes by subdural electrodes inserted through the foramen ovale is described. Experience with this technique in 13 candidates for surgical epilepsy therapy is presented. Our results indicate that interictal epileptiform potentials as well as ictal discharges are reliably picked up by the foramen ovale electrode whenever nucleus amygdalae, hippocampus and parahippocampal gyrus show synchronous epileptic activity. The advantages of this technique are discussed.
Cryptic Vascular Malformations Diagnosed by Stereotactic Biopsies – A Preliminary Study
Authors: Daumas-Duport C. , Mann M. , Munari C. , Blond S. , Musolino A. , Monsaingeon V. , Chodkiewicz J.P.
Published: March 2007

A series of 14 cryptic vascular malformations (CVM) deeply situated or Iocalized in functional cortical areas were diagnosed by serial stereotactic biopsies. No history was suggestive of hemorrhage, despite a substantial hematoma being evacuated during biopsy procedures in 4 patients. Retrospectively, CVM without hematoma were found to have certain characteristics that should raise the suspicion as to the correct diagnosis. At the time of discharge from the hospital, only 1 patient had mild aggravation of a preexisting motor deficit, which further improved. Serial stereotactic biopsies provided the required histological diagnosis with relatively low risk.
Cell Kinetics of Neuroepithelial Tumors in Serial Stereotactic Biopsies. A New Combined Approach
Authors: Broggi G. , Franzini A. , Costa A. , Melcarne A. , Allegranza A.
Published: March 2007

33 consecutive patients with brain glial tumors underwent serial stereotactic biopsies and (3H)-thymidine in vitro investigation. The labeling index has been determined in each case and matched with the WHO histological classification. The feasibility and the accuracy of cell kinetics study applied to stereotactic biopsies are discussed in view of future application for prognostic purposes. Particular attention is given to the description of the method.
Mechanism of Neuroadenolysis of the Pituitary for Cancer Pain Control
Authors: Trouwborst A. , Yanagida H. , Erdmann W. , Kok A.
Published: March 2007

Several theories have been advanced to explain how neuroadenolysis of the pituitary (NALP) relieves cancer pain. Interference with hormonal regulation, interruption of pain pathways and a compensatory overproduction of brain endorphins have been proposed. The purpose of the present experimental study is to determine whether neuronal activity of the pituitary gland, as related to the primary somatosensory cortex (PSC), may be involved in the pain perception pathway influenced by NALP, using EEG and tooth pulp evoked potentials (TPEPs). Pituitary activity showed a high voltage slow activity which slowed after alcohol injection into the sella turcica. When naloxone was injected after NALP, a rhythmic high voltage activity appeared in the pituitary gland.After NALP, the TPEP recorded from the PSC disappeared, while NALP induced an increase in the amplitude of the TPEP in the pituitary gland. An injection of naloxone severely decreased this response in the pituitary gland, in contrast to changes in the PSC where the original response reappeared after an injection of naloxone.Our hypothesis is that an increase of TPEPs (hyperactivity) in the pituitary gland is produced after alcohol wounding (wounding effect), leading to a decrease of pain response in the sensory cortex (decrease of TPEPs). This wound effect may be influenced by endorphins, because naloxone, a specific antagonist of opiate receptors, reversed the changes in TPEPs in both places.
Diagnosis and Repair of Malfunctions of Implanted Central Nervous System Stimulators
Authors: Koeze T.H. , Simpson B.A. , Watkins E.S.
Published: March 2007

Neurostimulator malfunctions must be located and repaired if patients are to receive maximum benefit from central nervous system stimulation. This report lists the problems encountered with the stimulators from four manufacturers. Procedures for locating the source of malfunctions are discussed in some detail.
Inhibition of Nociceptive Neurons by Internal Capsule Stimulation
Authors: Nishimoto Akira , Namba Shimpei , Nakao Yoshikuni , Matsumoto Yuzo , Ohmoto Takashi
Published: March 2007

The mechanism of pain relief by internal capsule (IC) stimulation was investigated in 32 adult cats. Nociceptive neuronal activity of the nucleus ventralis postero-medialis (VPM), responding to contralateral pulp stimulation, was suppressed by IC stimulation to a greater extent than activity in the posterior nuclear group (PO) or centre-median nucleus. On the contrary, suppression of neuronal firing by intraventricular morphine-HCl predominated in PO neurons. These results suggest that pain relief by IC stimulation may be mediated through inhibitory effects on nociceptive neurons of the thalamic sensory relay nuclei.
A New Dynamometric Technique to Measure and Locate Endocranial Structures
Authors: Colombo F. , Angrilli F. , Basso R. , Benedetti A. , Casentini L.
Published: March 2007

An apparatus for measuring and recording the resistance to penetration of endocranial tissue has been planned and built. The probe carrier, driven by a constant-speed electric motor, is fitted onto a stereotactic head frame which is used to guide the tool to the intended target. The displacement and resistance encountered when the tool penetrates intracranial structures are measured and recorded on an x-y recorder. Preliminary tests performed on calf brain specimens have documented that the apparatus can measure the different consistencies of normal cerebral tissue and suggest a new technique for morphological investigations based on the mechanical consistency of normal and pathological organic tissue. Moreover, the hypothesis of a plastic deformation in cerebral tissue has been confirmed, in that the same apparatus permits one to measure the displacement of tissues caused by the advancement of the surgical tool.
Electrical Stimulation of the Posterior Limb of the Internal Capsule for Treatment of Thalamic Pain
Authors: Namba Shimpei , Nakao Yoshikuni , Matsumoto Yuzo , Ohmoto Takashi , Nishimoto Akira
Published: March 2007

Electrical stimulation of the posterior limb of the internal capsule was performed in 7 patients with thalamic pain who had developed dysesthesia, hyperpathia and/or spontaneous burning pain. Ramped bipolar stimulation elicited sensory responses, such as warm or comfortable sensation. Follow-up from 9 months to 2 years and 7 months showed that 3 patients had a good result, two had fair and the remaining two had poor results. No serious side effects were seen. The mechanism of pain relief by the internal capsule stimulation is discussed.
Neurosurgical Management of Epilepsy: A Personal Perspective in 1983
Authors: Ojemann George A.
Published: March 2007

The therapeutic goal in the neurosurgical treatment of medically intrac-table epilepsy is complete seizure, control, for both biologie and psychosocial reasons. Cortical resections are more likely to accomplish this than other surgical alternatives for epilepsy. Although abnormalities on new imaging techniques (CT, positron emission scanning) aid in identifying the epileptic focus, interictal epileptiform EEG changes remain the main indicator of focal origin of the seizures. Where this is equivocal, direct brain recording of spontaneous seizures with subdural electrodes is of value in identifying the side and lobe of seizure onset. The cortical resection is then tailored by the extent of the interictal electrocorticographic abnormalities and functional identification of essential areas such as those for language, using an electrical stimulation mapping technique, under local anesthesia. With this approach, half of the patients with temporal lobe foci are seizure-free since the time of operation, over two-thirds become so with time, and over three-quarters have at least very major reductions in seizure frequency.
The Role of Stereotactic Amygdalotomy in the Treatment of Temporal Lobe Epilepsy Associated with Behavioral Disorders
Authors: Hood T.W. , Siegfried J. , Wieser H.G.
Published: March 2007

The efficacy of bilateral stereotactic amygdalotomy for the treatment of aggressive behavioral disorders has been evaluated in a retrospective study of 67 cases. In addition 4 cases with complex partial seizures accompanied by aggressive outbursts revealing a unilateral epileptogenic focus in the amygdala or periamygdala region during preoperative stereoelectroencephalographic (SEEG) evaluation received a unilateral stereotactic amygdalotomy. Long-term follow-up of these 4 cases shows that 3 patients had considerable improvement in seizure frequency and severity as well as behavioral disturbances. The results in the remaining patients evaluated by surface EEG were inconclusive
The Indications for and the Role of Depth Electrode Recording in Epilepsy
Authors: Olivier André , Gloor Peter , Quesney Felipe , Andermann Frederick
Published: March 2007

A series of 47 patients studied with stereotactically implanted depth electrodes is analyzed. Indications and grouping of the patients fall into three main categories: (a) the bitemporal series (35 patients) where there is ambiguity as to the lateralization of the focus; (b) the unilateral series (6 patients) where the problem is one of localization within one hemisphere, and (c) the generalized series where one tries to determine the primary focus in secondary generalized seizures (6 patients). The best indication appears to be the bitemporal cases, in which a large number of attacks can be recorded by computer. Most of them tend to have a well-lateralized onset in one of the temporal lobes; 32 of the 35 implanted patients were operated upon (91.4%). The results on the seizure tendency in these patients is comparable, if not superior, to those obtained in the socalled unilateral cases. Correlation studies indicate that interictal activity is a good indicator of the predominance of seizures.
Outcomes and Indications of Corpus callosum Section for Intractable Seizure Control
Authors: Rayport Mark , Ferguson Shirley M. , Corrie W. Stephen
Published: March 2007

Callosotomy (CCS) was performed in 9 cases of rigorously classified drug-refractory epilepsy not eligible for focal cortical resection. Complete CCS was carried out in two stages in 8 patients. 1 case had an anterior CCS only. None of the 9 patients has become seizure free. In 7, seizure frequency has diminished by a factor of 3–60 for at least one seizure type. Drop attacks in 2 cases have ceased. Clinical seizure patterns appeared more helpful in predicting outcome than preoperative EEG and stereoelectroencephalographic studies. Complete CCS may result in prolonged behavioral disturbances in the areas of language, hemisphere competition and attention-memory sequencing with impact on the sphere of daily living.
Anterior Callosotomy and Chronic Depth Electrode Recording in the Surgical Management of Some Intractable Seizures
Authors: Bouvier G. , Mercier C. , St. Hilaire J.M. , Giard N. , Labrecque R. , Beique R.A.
Published: March 2007

Chronic depth electrode recording has proven to be a safe and indispen-sable tool for the investigation of intractable seizures. Anterior callosotomy appears as an excellent palliative treatment at least in bifrontal foci. It is hoped that chronic depth electrode recording will be used more widely before callosotomy in order to establish more clearly the best indication for such a surgical procedure.
Reduction of Intractable Seizures Using Cerebellar Stimulation
Authors: Davis Ross , Gray Edward , Engle Howard , Dusnak Alice
Published: March 2007

Of the 32 patients with active intractable seizures, 27 had spastic cerebral palsy (CP) and 5 had epilepsy (EP), and all underwent chronic cerebellar stimulation (CCS) (amplitude 1–2 µC/cm2phase, rate 10–180 pps, duration of implantation 0.5–7 years, average 4.5 years). Grand mal seizures occurred in 23 patients (19 CP, 4 EP); with CCS 17 patients stopped, 4 had a reduction, 3 were unchanged. Petit mal occurred in 9 patients (8 CP, 1 EP); with CCS 4 patients ceased seizuring, 3 reduced and 2 were unchanged. Myoclonic seizures were present in 6 patients (5 CP, 1 EP); with CCS 1 patient stopped, 3 had a reduction while 2 patients were unaffected. Severe psychomotor seizuring affected 2 EP patients, 1 had a marked behavioral improvement and finally stopped seizuring for the past 9 months. Overall, CCS stopped 18 (57%) of the patients seizuring, reduced a further 9 (28%), with no effect in 5 patients (15%).
Experimental Tremor Produced by Ventromedial Tegmental Lesion in Monkeys
Authors: Nakaoka Tsutomu
Published: March 2007

Destruction of the ventromedial tegmentum (VMT) of the midbrain in the monkey has been known to produce tremor similar to that seen in Parkinson''s disease. A neuroanatomical study by a silver impregnation method was conducted on 5 monkeys, demonstrating the characteristic flexed posture with hypokinesia of the contralateral upper limb (reliable premonitory sign of tremor) following destruction of VMT with a histologically proven lesion site. The results are summarized as follows: (1) the tractus nigrostriatus, (2) tractus tegmentalis centralis, (3) ascending fiber bundes going to the thalamus (particulary VL.X and VPLo) and (4) descending fibers leading to the bilateral substantia nigra constitute the bulk, if not all, of those neural tracts which pass through the VMT. This, along with the proven existence of fibers projecting to the thalamic nuclei, is thought to account for the rhythmic burst discharges recorded from the VL or Vim nucleus in the monkey and in Parkinson''s disease patients. The present experimental study also seems to provide an additional anatomical basis for the concept that the tractus tectonigralis is involved in the mechanism of development of kinésie paradoxale.
Thalamic Stimulation for Control of Movement Disorders
Authors: Andy O.J.
Published: March 2007

Chronic recurrent thalamic stimulation has been effective in alleviating a variety of movement disorders. In contrast to thalamic lesions. it is preferred for the treatment of intractable motor disorders in low-risk elaerly patients and patients with diffuse brain Iesions secondary to trauma. Abnormal diencephalic electrical discharges have been observed and thought to be associated, in some way, with either generating or sustaining the movement abnormalities. The beneficial effects are ascribed to an electrophysiologic functional ablation of the discharging systems. This interpretation is based on the observation that the diencephalic discharges are attenuated by the applied stimulation and that the beneficial effects are reversible even after several months of applied therapeutic stimulation.
Combined Electrical Stimulation of the Periaqueductal Gray Matter and Sensory Thalamus
Authors: Hosobuchi Yoshio
Published: March 2007

11 patients with chronic intractable pain of at least 3 years'' duration underwent a morphine infusion test, the results of which suggested a syndrome of superimposed somatogenic and neurogenic pain components. They then underwent stereotactic implantation of a dual-channel brain stimulation system with two brain electrodes, one in the left periaqueductal gray matter (PAG) and the other in the sensory thalamus contralateral to the neurogenic pain. Using this system, all patients have obtained excellent simultaneous relief of both pain components (follow-up 12–36 months). The findings support a notion of two separate sensory modulating systems. They indicate that combined electrical stimulation of the PAG and sensory thalamus is a technically feasible and clinically satisfactory modality for the control of pain in humans, and they appear to indicate that better pain control is obtained by continuous, cycled stimulation of the PAG than by the conventional mode of stimulation.
Percutaneous Radiofrequency Glossopharyngeal Rhizotomy for Cancer Pain
Authors: Pagura Jorge Roberto , Schnapp Moacir , Passarelli Pascoal
Published: March 2007

15 patients with pain secondary to cancer underwent radiofrequency glossopharyngeal rhizotomy by the percutaneous approach. 11 patients had complete relief while 4 patients had partial relief. All patients presented, after surgery, some impairment in glossopharyngeal function.
Stereotactic Radiofrequency Lesion Making
Authors: Cosman E.R. , Nashold B.S. , Bedenbaugh P.
Published: March 2007

The physical principles of radiofrequency (RF) lesion making in stereotactic neurosurgery are summarized. Empirical data are given on the relationship between lesion size and lesioning parameters. Currently accepted ranges of lesioning parameters for selected stereotactic procedures are discussed. Advanced RF lesion electrode designs are described which improve the capabilities to reach and confirm targets.
Neuroleptic Analgesia for Stereotactic Surgery
Authors: Zukic A. , Kelly Patrick J.
Published: March 2007

This report describes the technique of neuroleptic analgesia which was used to perform a variety of stereotactic procedures. The method provides optimal operating conditions for the surgeon while maintaining a high degree of physiologic and neurologie stability for the patient. 51 patients in our series underwent various stereotactic procedures with no intraoperative complications or postoperative morbidity.
The Role of Computed Tomographic and Digital Radiographic Techniques in Stereotactic Procedures for Electrode Implantation and Mapping, and Lesion Localization
Authors: Peters T.M. , Olivier A. , Bertrand G.
Published: March 2007

This paper describes a computer-based system for analyzing stereotactic CT scans and angiograms. Simple Plexiglas frames containing metallic marker pellets and rods are affixed to the sides of the frame during CT scanning and angiography. The images of these markers are recognized by the computer program and used to compute the frame coordinate system. Coordinates of a lesion on CT and angiogram images may be readily computed and coordinate sets specified by the operator may be displayed on the imager, along with positions of implanted electrodes and a numerical indication of recorded activity for each site.
Digital Radiography for Target Point Evaluation in Stereotactic Neurosurgery
Authors: Fröder M. , Seitzer D. , Büren G. , Dieckmann G.
Published: March 2007

Today, the usual target point evaluation during stereotactic operations using planar X-ray films can be supplemented by digital video storage. The picture-delivering system is a digital X-ray video chain which replaces the X-ray film. Evaluation of target point coordinates as well as parameters of electrode approach and positioning are determined by a microcomputer. Such an inexpensive system is described.
Stereotactic Biopsy of Cerebral Space-Occupying Lesions
Authors: Bouvier G. , Couillard P. , Leger S.L. , Lesage J. , Rotent F. , Beique R.A.
Published: March 2007

Brain imaging has improved and more and more cerebral lesions are discovered. A direct surgical approach can be dangerous. Stereotatic biopsy appears as an excellent alternative because it provides one not only with a precise histological diagnosis but also gives a real three-dimensional picture of a lesion.
Stereotactic Localization of Deep-Seated Arteriovenous Malformations in the Functional Area
Authors: Yamada Shokei , Ritland Stephen , Knierim David
Published: March 2007

The authors approached 5 arteriovenous malformations (AVMs) located deep in functional areas of the cortex with major draining veins found in the mesial hemisphere by using the stereotactic method. This procedure is a useful adjunct to total resection of these AVMs. No mortality or significant morbidity was noted after the surgical procedure. The authors believe that direct attack on AVMs in areas of critical function is the procedure of choice in order to preserve neurological function.
Microiontophoretically Applied THIP Effects upon Nociceptive Responses of Neurons in Medial Thalamus
Authors: Reyes-Vázquez C. , Dafny N.
Published: March 2007

Sprague-Dawley rats anesthetized with urethane were used to study the single cell responses of medial thalamic neurons following noxious input and their inter-actions with γ-aminobutyric acid (GABA) agonist THIP (4,5,6,7-tetrahydroisoxazo-Io[5,4-c]pyridin-3-ol) and morphine sulfate applied microintophoretically. The majority of the medial thalamic neurons responded to noxious stimulation by an increase in their firing rate. Local application of both THIP and morphine attenuated the spontaneous and the noxious evoked responses of these neurons. The possibility of a role for GABA in mediating nonopiate pain suppression is discussed.
A New Head Clamp for Stereotactic and Intracranial Procedures
Authors: Olivier André , Bertrand Gilles
Published: March 2007

The authors have devised a clamp to fïx the head to the surgical table during stereotactic procedures for placement of depth electrodes. The main advantages of this device derive from the rigid immobilization of the head. The clamp facilitates fixation of the stereotactic frame to the head, percutaneous twist drill trephination of any site of the skull, X-ray centering with a laser beam, mobilization of contrast material during ventriculography or pneumoencephalography, and placement of epidural screws. This head clamp can also be used during craniotomies for fixation of the head and support for brain retractors.
Reliability of Stereotactic Biopsy
Authors: de Divitiis Enrico , Spaziante Renato , Cappabianca Paolo , Caputi Franco , Pettinato Guido , Del Basso De Caro Marialaura
Published: March 2007

Because of the variability of the structural features of cerebral tumors, the characteristics observed in biopsy samples may not be representative of the whole neoplasm. The reliability of cerebral stereotactic biopsy is therefore greatly debated. In order to test the value of diagnoses based on biopsy samples, the authors compared histological and cytological data obtained from a small fragment of a tumor with the definitive diagnosis obtained from surgical or necropsy specimens. An analysis of 64 cases is reported, where a correct diagnosis from the biopsy sample was achieved in 92.2% of the cases. Neuroglial tumors were more difficult to characterize than other types of intracranial tumors, with an accuracy of 81.5 %.
Dual Channel Optical Tomographic Imaging of Leukocyte Recruitment and Protease Activity in the Healing Myocardial Infarct
Authors: Nahrendorf Matthias , Sosnovik David E. , Waterman Peter , Swirski Filip K. , Pande Ashvin N. , Aikawa Elena , Figueiredo Jose-Luiz , Pittet Mikael J. , Weissleder Ralph
Published: March 2007

Inflammatory responses after myocardial infarction profoundly impact tissue repair. Yet, efficient tools to serially and noninvasively assess cellular and molecular functions in postinfarct inflammation are lacking. Here we use multichannel fluorescent molecular tomography (FMT) for spatiotemporal resolution of phagocytic and proteolytic activities mediated by macrophages and neutrophils in murine infarcts. We performed FMT imaging to compare the course of efficient and impaired healing in wild-type and FXIII
−/–
mice, respectively. Mice subjected to coronary ligation received simultaneous injections with Prosense-680, an activatable fluorescence sensor reporting on cathepsin activity, and CLIO-VT750, a magneto-fluorescent nanoparticle for imaging of phagocyte recruitment. On FMT, Prosense-680 infarct signal was 19-fold higher than background (
P
<0.05). Protease activity was higher in the infarcted lateral wall than in the remote, uninjured septum on ex vivo fluorescence reflectance imaging (contrast to noise ratio 118±24). CLIO-VT750 FMT signal coregistered with contrast enhancement in the hypokinetic infarct on MRI. Microscopic fluorescence signal colocalized with immunoreactive staining for cathepsin, macrophages and neutrophils. Flow cytometry of digested infarcts revealed monocytes/macrophages and neutrophils as the source of the fluorescence signal. Phagocytic activity peaked on day 6, and proteolytic activity peaked on day 4 after myocardial infarction. FMT detected impaired recruitment of phagocytes and protease activity in FXIII
−/−
mice (
P
<0.05). FMT is a promising noninvasive molecular imaging approach to characterize infarct healing. Spectrally resolved imaging agents allow for simultaneous assesment of key processes of in vivo cellular functions. Specifically, we show that in vivo FMT detects impaired healing in FXIII
−/−
mice.
Identification of Atherosclerotic Lipid Deposits by Diffusion-Weighted Imaging
Authors: Qiao Ye , Ronen Itamar , Viereck Jason , Ruberg Frederick L. , Hamilton James A.
Published: March 2007

Objectives—

The content and distribution of lipids is an important aspect of plaque vulnerability, but lipids are present within a heterogeneous environment, impeding detection by magnetic resonance imaging. Our goal was to achieve accurate detection of mobile lipids by a single magnetic resonance imaging sequence.

Methods and Results—

Carotid endarectomy specimens (n=23) were imaged ex vivo at a high magnetic field (11.7 T) within 24 hours after surgery. Three contrast-weighted (T1W, T2W, and diffusion-weighted imaging [DWI]) image sequences were acquired and then coregistered with histological preparations for lipids (Oil red O and polarized light microscopy) and fibrous tissue (trichrome). Contrast-to-noise ratios were measured and compared for the 3 contrast weightings. Contrast-to-noise ratio measurement in regions identified as lipid versus fibrous tissue showed greater differences by DWI (4.5±0.63 versus 0.64±0.08;
P
<0.05) as compared with T2W (2.83±0.36 versus 1.36±0.37;
P
<0.05). We validated the presence and distribution of lipids (mainly cholesteryl esters) by both histology and image-guide spectroscopy. The basis for distinguishing mobile lipid and water inside the plaque was illustrated by diffusion-weighted spectroscopy.

Conclusions—

Biophysical properties of plaque lipids can confer selective identification by DWI, as opposed to standard T1W and T2W imaging sequences. Successful translation of DWI in vivo could identify of features of vulnerable plaque.
Effects of Poststroke Losartan Versus Captopril Treatment on Myogenic and Endothelial Function in the Cerebrovasculature of SHRsp
Authors: Smeda John S. , McGuire John J.
Published: March 2007

Background and Purpose—We assessed the ability of poststroke captopril and losartan treatment to reverse myogenic and endothelial dysfunction in the middle cerebral arteries of Kyoto-Wistar stroke-prone spontaneously hypertensive rats (SHRsp) that developed intracerebral hemorrhagic stroke.

Methods—SHRsp were sampled before and after stroke development and after up to 37 days of captopril (50 mg/kg per day) or losartan (35 mg/kg per day) treatment initiated after stroke. Pressure-dependent constriction to a 100-mm Hg pressure step, constriction to nitric oxide synthase inhibition (100 μmol/LNω-nitro-l-arginine methyl ester), and endothelium-dependent vasodilation to bradykinin (1.6 μmol/L), 2-f-LIGRLO-NH2(1 μmol/L, a protease-activated receptor-2 agonist), and A23187 (2 μmol/L) were evaluated in middle cerebral arteries at 100 mm Hg with a pressure myograph.

Results—Middle cerebral arteries from SHRsp with stroke could not constrict to pressure or nitric oxide synthase inhibition, lacked the ability to vasodilate to bradykinin, and exhibited attenuated dilation and vasomotion in response to A23187. Vasodilation to 2-f-LIGRLO-NH2was unaltered. The aforementioned cerebrovascular alterations were reversed after 31 days of poststroke losartan but not of captopril treatment in the absence of an antihypertensive effect. Captopril treatment restored middle cerebral artery constriction to pressure, NOS inhibition, and bradykinin vasodilation temporarily after 7 to 18 days of treatment, after which function deteriorated to a level observed in SHRsp at stroke.

Conclusions—Aspects of poststroke cerebrovascular dysfunction, which likely play an important role in altering and modulating cerebral blood flow autoregulation, can be reversed in SHRsp more effectively after stroke development by blocking angiotensin II type 1 receptors as opposed to lowering angiotensin II levels.
Prevalence and Determinants of Subdiaphragmatic Visceral Infarction in Patients With Fatal Stroke
Authors: Abboud Halim , Labreuche Julien , Gongora-Riverra Fernando , Jaramillo Arturo , Duyckaerts Charles , Steg Philippe Gabriel , Hauw Jean-Jacques , Amarenco Pierre
Published: March 2007

Background and Purpose—

Arterial thromboembolism is a common cause of both visceral and brain infarctions. Because the cause of brain infarction is unknown in up to 39% of patients, the discovery of subdiaphragmatic visceral infarction (SDVI) in this context is important, but its frequency is unknown. We therefore investigated the prevalence of SDVI in subjects who died from stroke. We also evaluated the yield of SDVI diagnosis for stroke subtyping.

Methods—

We performed a case–control study using a series of 815 consecutive autopsies of patients who had died from a neurological disease, including 350 with stroke (260 infarcts and 90 hemorrhages). We systematically assessed the presence of renal, splenic, and mesenteric infarction (no case of spinal cord was recorded) and analyzed their determinants in patients with stroke. Patients with other neurological diseases served as the control group.

Results—

Renal infarction was the most frequent SDVI (10.2%), whereas mesenteric infarction was rare (1.1%). At least one SDVI was found in 16.9% of patients with stroke (38.7% of patients with a cardioembolic stroke) and in 5.1% of patients with other neurological diseases (adjusted OR=2.12; 95% CI=1.08 to 4.16). Among patients with stroke, a significant heterogeneity in the prevalence of SDVI was found across etiological stroke subgroups with only three patients (3.3%) with hemorrhagic stroke having an SDVI (2 mesenteric and one renal infarction) compared with 56 patients (21.5%) with ischemic stroke (
P
<0.0001). Among patients with brain infarction and a SDVI, 76.8% had a definite cardiac source of embolism.

Conclusions—

In patients with fatal brain infarction, the prevalence of SDVI is higher than previously thought, especially in those with stroke attributed to cardiac emboli. Seeking SDVI may assist in the etiologic diagnosis of brain infarction
Are Circulating Endothelial-Derived and Platelet-Derived Microparticles a Pathogenic Factor in the Cisplatin-Induced Stroke?
Authors: Periard Daniel , Boulanger Chantal M. , Eyer Stephan , Amabile Nicolas , Pugin Paul , Gerschheimer Christiane , Hayoz Daniel
Published: March 2007

Background and Purpose—

To evaluate whether cisplatin-induced stroke is mediated by vascular toxicity with release of prothrombotic endothelial and platelet-derived microparticles (MPs).

Methods—

Endothelial (CD31
+
CD41
−
), platelets (CD31
+
CD41
+
) and prothrombotic (Annexin V
+
) circulating MPs were quantified by flow cytometry in 18 patients with cancer, before and 3 days after administration of cisplatin, and compared with 18 healthy controls. Thrombin-antithrombin complex and prothrombin fragments (F
1+2
) were measured as markers of the activation of the coagulation.

Results—

In patients with cancer, baseline levels of circulating prothrombotic, endothelial and platelet-derived MPs were similar to healthy controls and decreased significantly after administration of cisplatin. High-baseline MPs levels were observed in 5 patients who received cisplatin for a second or third cycle. A high-baseline activation of the coagulation was observed in all patients without further increase after cisplatin infusion.

Conclusion—

Cisplatin treatment is immediately followed by a decrease in circulating levels of endothelial and platelet-derived MPs. However, a transient increase in MPs is observed at the second and third infusion, and this may contribute to the cisplatin-induced stroke.
Evidence for the Role of Endogenous Carbon Monoxide in Memory Processing
Authors: Cutajar M. C. , Edwards T. M.
Published: March 2007

For a decade and a half, nitric oxide (NO) has been implicated in memory processing across a wide variety of tasks and species. Comparatively, endogenously produced carbon monoxide (CO) has lagged behind as a target for research into the pharmacological processes underlying memory formation. This is surprising given that CO is formed in memory-associated brain regions, is structurally similar to NO, and along with NO can activate guanylate cyclase, which is an enzyme well characterized in memory processing. Nevertheless, a limited number of electrophysiological investigations have concluded that endogenous CO is involved in long-term potentiation. Although not evidence for a role in memory per se, these studies did point to the possible importance of CO in memory processing. In addition, there is now evidence to suggest that endogenous CO is important in avoidance learning and possible for other tasks. This review therefore seeks to promote endogenous CO as a potentially important target for memory research.
Temporal Dynamics of the Attentional Spotlight: Neuronal Correlates of Attentional Capture and Inhibition of Return in Early Visual Cortex
Authors: Müller Notger G. , Kleinschmidt Andreas
Published: March 2007

A stimulus that suddenly appears in the corner of the eye inevitably captures our attention, and this in turn leads to faster detection of a second stimulus presented at the same position shortly thereafter. After about 250 msec, however, this effect reverses and the second stimulus is detected faster when it appears far away from the first. Here, we report a potential physiological correlate of this time-dependent attentional facilitation and inhibition. We measured the activity in visual cortex representations of the second (target) stimulus' location depending on the stimulus onset asynchrony (SOA) and spatial distance that separated the target from the preceding cue stimulus. At an SOA of 100 msec, the target yielded larger responses when it was presented near to than far away from the cue. At an SOA of 850 msec, however, the response to the target was more pronounced when it appeared far away from the cue. Our data show how the neural substrate of visual orienting is guided by immediately preceding sensory experience and how a fast-reacting brain system modulates sensory processing by briefly increasing and subsequently decreasing responsiveness in parts of the visual cortex. We propose these activity modulations as the neural correlate of the sequence of perceptual facilitation and inhibition after attentional capture.
Event-related Potential Evidence of Form and Meaning Coding during Online Speech Recognition
Authors: Friedrich Claudia K. , Kotz Sonja A.
Published: March 2007

It is still a matter of debate whether initial analysis of speech is independent of contextual influences or whether meaning can modulate word activation directly. Utilizing event-related brain potentials (ERPs), we tested the neural correlates of speech recognition by presenting sentences that ended with incomplete words, such as To light up the dark she needed her can-. Immediately following the incomplete words, subjects saw visual words that (i) matched form and meaning, such as candle; (ii) matched meaning but not form, such as lantern; (iii) matched form but not meaning, such as candy; or (iv) mismatched form and meaning, such as number. We report ERP evidence for two distinct cohorts of lexical tokens: (a) a left-lateralized effect, the P250, differentiates form-matching words (i, iii) and form-mismatching words (ii, iv); (b) a right-lateralized effect, the P220, differentiates words that match in form and/or meaning (i, ii, iii) from mismatching words (iv). Lastly, fully matching words (i) reduce the amplitude of the N400. These results accommodate bottom-up and top-down accounts of human speech recognition. They suggest that neural representations of form and meaning are activated independently early on and are integrated at a later stage during sentence comprehension.
Overcoming Perceptual Features in Logical Reasoning: A Parametric Functional Magnetic Resonance Imaging Study
Authors: Prado Jérôme , Noveck Ira A.
Published: March 2007

Participants experience difficulty detecting that an item depicting an H-in-a-square confirms the logical rule, “If there is not a T then there is not a circle.” Indeed, there is a perceptual conflict between the items mentioned in the rule (T and circle) and in the test item (H and square). Much evidence supports the claim that correct responding depends on detecting and resolving such conflicts. One aim of this study is to find more precise neurological evidence in support of this claim by using a parametric event-related functional magnetic resonance imaging (fMRI) paradigm. We scanned 20 participants while they were required to judge whether or not a conditional rule was verified (or falsified) by a corresponding target item. We found that the right middorsolateral prefrontal cortex (mid-DLPFC) was specifically engaged, together with the medial frontal (anterior cingulate and presupplementary motor area [pre-SMA]) and parietal cortices, when mismatching was present. Activity in these regions was also linearly correlated with the level of mismatch between the rule and the test item. Furthermore, a psychophysiological interaction analysis revealed that activation of the mid-DLPFC, which increases as mismatching does, was accompanied by a decrease in functional integration with the bilateral primary visual cortex and an increase in functional integration with the right parietal cortex. This indicates a need to break away from perceptual cues in order to select an appropriate logical response. These findings strongly indicate that the regions involved in inhibitory control (including the right mid-DLPFC and the medial frontal cortex) are engaged when participants have to overcome perceptual mismatches in order to provide a logical response. These findings are also consistent with neuroimaging studies investigating the belief bias, where prior beliefs similarly interfere with logical reasoning.
Numbers within Our Hands: Modulation of Corticospinal Excitability of Hand Muscles during Numerical Judgment
Authors: Sato Marc , Cattaneo Luigi , Rizzolatti Giacomo , Gallese Vittorio
Published: March 2007

Developmental and cross-cultural studies show that finger counting represents one of the basic number learning strategies. However, despite the ubiquity of such an embodied strategy, the issue of whether there is a neural link between numbers and fingers in adult, literate individuals remains debated. Here, we used transcranial magnetic stimulation to study changes of excitability of hand muscles of individuals performing a visual parity judgment task, a task not requiring counting, on Arabic numerals from 1 to 9. Although no modulation was observed for the left hand muscles, an increase in amplitude of motor-evoked potentials was found for the right hand muscles. This increase was specific for smaller numbers (1 to 4) as compared to larger numbers (6 to 9). These findings indicate a close relationship between hand/finger and numerical representations.