[Machine learning for resting state fMRI-based preoperative mapping: comparison with task-based fMRI and direct cortical stimulation]. / Primenenie mashinnogo obucheniya dlya predoperatsionnogo kartirovaniya po dannym funktsional'noi magnitno-rezonansnoi tomografii pokoya: sravnenie so stimul-zavisimoi funktsional'noi magnitno-rezonansnoi tomografiei i pryamoi elektricheskoi stimulyatsiei kory.

OBJECTIVE: To develop a system for preoperative prediction of individual activations of motor and speech areas in patients with brain gliomas using resting state fMRI (rsfMRI), task-based fMRI (tb-fMRI), direct cortical stimulation and machine learning methods. MATERIAL AND METHODS: Thirty-three patients with gliomas (19 females and 14 males aged 19 - 540) underwent DCS-assisted resection of tumor (19 ones with lesion of motor zones and 14 patients with lesions of speech areas). Awake craniotomy was performed in 14 cases. Preoperative mapping was performed according to special MRI protocol (T1, tb-fMRI, rs-fMRI).Machine learning system was built on open source data from The Human Connectome Project. MR data of 200 healthy subjects from this database were used for system pre-training. Further, this system was trained on the data of our patients with gliomas. RESULTS: In DCS, we obtained 332 stimulations including 173 with positive response. According to comparison of functional activations between rs-fMRI and tb-fMRI, there were more positive DCS responses predicted by rs-fMRI (132 vs 112). Non-response stimulation sites (negative) prevailed in tb-fMRI activations (69 vs 44). CONCLUSION: The developed method with machine learning based on resting state fMRI showed greater sensitivity compared to classical task-based fMRI after verification with DCS: 0.72 versus 0.66 (p<0.05) for identifying the speech zones and 0.79 versus 0.62 (p<0.05) for motor areas.

[Conduction aphasia in patients with glioma in the left hemisphere]. / Provodnikovaya afaziya u bol'nykh s gliomami levogo polushariya.

Background. According to Wernicke-Geschwind model, conduction aphasia following arcuate tract lesion was canonized as primary disorder of repetition in relatively intact speech. OBJECTIVE: Syndromic analysis of speech and writing disorders in patients with arcuate tract lesion using the method by A.R. Luria and their comparison with well-known types of aphasia. MATERIAL AND METHODS: Clinical and neuropsychological survey was performed in 14 patients with gliomas who underwent surgical treatment at the Burdenko Neurosurgical Center (10 gliomas of the frontal lobe and 4 tumors of the temporal lobe). All patients underwent MRI, HARDI MRI tractography and A.R. Luria's neuropsychological examination prior to surgery and after 5-6 postoperative days. Thirteen patients underwent awake craniotomy, 3 of them were examined one year after surgery. RESULTS: In all patients, the tumor was localized near arcuate tract and its infiltration was noted. No intraoperative damage to the tract was ever noted according to speech monitoring data. However, postoperative edema followed by infiltration and dislocation of the tract (in all patients), as well as local ischemia in 4 patients were observed. After resection of prefrontal and premotor gliomas, aphasia included frontal (perseveration) and temporal components (disorders of naming, auditory-speech memory). Unusual verbal paraphrases were noted. We also observed severe violation of writing (temporal type) even if spontaneous speech and repetition were preserved. In case of resection of deep posterior temporal gliomas, speech disorders included signs of frontal lobe lesion (perseveration) and writing disorders. Similar motor abnormalities were identified in writing. CONCLUSION: Arcuate tract lesion can result speech and writing disorders as signs of damage to certain cortical speech zones (frontal and temporal lobe). Violations of repetition were not predominant in any case. At the same time, interruption of connection between motor and auditory image of the word could be revealed in writing.

[Broca's area intraoperative mapping with cortico-cortical evoked potentials]. / Intraoperatsionnoe kartirovanie rechevoi zony Broka metodom registratsii kortiko-kortikal'nykh vyzvannykh potentsialov.

OBJECTIVE: Mapping of effective speech connections between the frontal and temporal lobes with cortico-cortical evoked potentials. MATERIAL AND METHODS: There were 3 patients with brain tumors in the left frontoparietal region. The neoplasms were localized in the dominant hemisphere near cortical speech centers and pathways. Cortico-cortical evoked potentials were intraoperatively recorded in response to bipolar stimulation with a direct current delivered through the subdural electrodes (single rectangular biphasic impulses with duration of 300 µs and frequency of 1 Hz). Stimulation intensity was gradually increased from 2 mA within 3-4 mA. Registration was carried out by averaging ECoG (30-50 stimuli in each session) in the 300-ms epoch after stimulus. Direct cortical stimulation was used to validate the results of cortico-cortical speech mapping with cortico-cortical evoked potentials. RESULTS: In our cases, we obtained cortico-cortical evoked potentials from inferior frontal gyrus after stimulation of superior temporal gyrus. In one case, this effective relationship was unidirectional, in the other two patients reciprocal. Mean latency of N1 peak was 65 ms (range 49.6-90 ms), mean amplitude 71 µV (range 50-100 µV). Cortico-cortical mapping data were confirmed by detection of Broca's area in 2 out of 3 cases out during direct cortical stimulation with maximum amplitude of N1 wave. «Awake craniotomy¼ protocol was applied. In one case, Broca's area was not detected during direct stimulation. No postoperative speech impairment was noted. CONCLUSION: Initial results of cortical mapping with cortico-cortical evoked potentials in a small sample confirmed its practical significance for analysis of cortical projections of effective speech communications between the frontal and temporal lobes. Further study of this method in large samples is required.

[Resting-state fMRI in preoperative non-invasive mapping in patients with left hemisphere glioma]. / Funktsional'naya magnitno-rezonansnaya tomografiya sostoyaniya pokoya v predoperatsionnom neinvazivnom kartirovanii u patsientov s gliomami levogo polushariya golovnogo mozga.

Maximum resection and preservation of neurological function are main principles in surgery of brain tumors, especially glial neoplasms with diffuse growth. Therefore, exact localizing of eloquent brain areas is an important component in surgical planning ensuring optimal resection with minimal postoperative neurological deficit. Functional MRI is used to localize eloquent brain areas adjacent to the tumor. This paper is an initial stage in analysis of resting-state fMRI in assessment of functional changes of neuronal activity caused by brain gliomas of different localization. We report two patients with glial tumors localized within the precentral gyrus of the left hemisphere and near speech area. Considering data of task-based and resting-state fMRI, as well as direct cortical stimulation, we propose a methodology for assessing the overlap of activations obtained by these methods.

[Intraoperative mapping of long association fibers in surgery of gliomas of the speech-dominant frontal lobe]. / Intraoperatsionnoe kartirovanie dlinnykh assotsiativnykh traktov v khirurgii gliom dominantnoi po rechi lobnoi doli.

Surgery of intracerebral tumors involving long association fibers is a challenge. In this study, we analyze the results of intraoperative mapping of the superior longitudinal, arcuate, and frontal aslant tracts in surgery of brain gliomas. PURPOSE: The study purpose was to compare the results of intraoperative mapping and the postoperative speech function in patients with gliomas of the premotor area of the speech-dominant frontal lobe, which involved the superior longitudinal, arcuate, and frontal aslant tracts, who were operated on using awake craniotomy. MATERIAL AND METHODS: Twelve patients with left frontal lobe gliomas were operated on: 11 patients were right-handed, and one patient was a left-hander retrained at an early age. Histological types of tumors were represented by Grade II diffuse astrocytomas (6 patients), Grade III anaplastic astrocytomas (1 patient), Grade IV glioblastoma (1 patient), Grade II oligodendroglioma (1 patient), and Grade III anaplastic oligodendrogliomas (3 patients). The mean age of patients was 45 (29-67) years; there were 6 males and 6 females. All patients underwent preoperative and postoperative MRI with reconstruction of the long association fibers and determination of the topographic anatomical relationships between the fibers and the tumor. Surgery was performed using the asleep-awake-asleep protocol with intraoperative awakening of patients. All patients underwent cortical and subcortical electrophysiological stimulation to control the localization of eloquent structures and to clarify the safe limits of resection. For intraoperative speech monitoring, a computerized naming test was used with naming of nouns or verbs, and automatic speech was evaluated (counting from 1 to 10, enumeration of months and days of the week), which was complemented by a talk with the patient. Speech disorders before, during, and after surgery were evaluated by a neuropsychologist. The mean current strength during direct electrical stimulation was 3 (1.9-6.5) mA. RESULTS: The association fibers were intraoperatively identified in all patients (SLF/AF in 11 patients; FAT in one patient). In 4 patients, the cortical motor speech area was intraoperatively mapped; in three cases, tumor resection was accompanied by speech disturbances outside the stimulation. During direct electrical stimulation, speech disturbances developed in 7 of 12 cases. All patients underwent control MRI within the first 48-72 h: total resection (more than 90% of the tumor) was performed in 7 cases; subtotal resection was achieved in two patients; partial resection was performed in two cases. According to postoperative MR tractography, the resected tumor bed was adjacent to the SLF/AF complex in 7 cases, located near the SLF/AF complex in three cases, and adjacent to the FAT in two cases. Postoperatively, 11 out of 12 patients had worsening of neurological symptoms in the form of various speech disturbances. In one patient, speech disturbances developed 2 days after surgery, which was associated with an increase in edema. On examination 3 months after surgery, severe speech disturbances remained in 1 patient. CONCLUSION: Resection of frontal lobe tumors in the speech-dominant hemisphere using early postoperative awakening is associated with a high rate of complex speech disorders due to injury to the SLF/AF complex and FAT. In these cases, intraoperative speech mapping with allowance for the course of long association fibers is an essential procedure. Preoperative tractography in combination with intraoperative speech mapping enables identification of association fibers of the SLF/AF complex and FAT, which may help to avoid severe conduction aphasia with poor speech recovery after tumor resection.

[Dynamics of functional MRI and speech function in patients after resection of frontal and temporal lobe tumors]. / Dinamika funktsional'noi MRT i rechevoi funktsii u bol'nykh posle udaleniia vnutrimozgovykh opukholei lobnoi i visochnoi dolei mozga.

RATIONALE: There are no studies on application of functional MRI (fMRI) for long-term monitoring of the condition of patients after resection of frontal and temporal lobe tumors. PURPOSE: The study purpose was to correlate, using fMRI, reorganization of the speech system and dynamics of speech disorders in patients with left hemisphere gliomas before surgery and in the early and late postoperative periods. MATERIAL AND METHODS: A total of 20 patients with left hemisphere gliomas were dynamically monitored using fMRI and comprehensive neuropsychological testing. The tumor was located in the frontal lobe in 12 patients and in the temporal lobe in 8 patients. Fifteen patients underwent primary surgery; 5 patients had repeated surgery. Sixteen patients had WHO Grade II and Grade III gliomas; the others had WHO Grade IV gliomas. Nineteen patients were examined preoperatively; 20 patients were examined at different times after surgery. Speech functions were assessed by a Luria's test; the dominant hand was determined using the Annette questionnaire; a family history of left-handedness was investigated. Functional MRI was performed on an HDtx 3.0 T scanner using BrainWavePA 2.0, Z software for fMRI data processing program for all calculations >7, p<0.001. RESULTS: In patients with extensive tumors and recurrent tumors, activation of right-sided homologues of the speech areas cold be detected even before surgery; but in most patients, the activation was detected 3 months or more after surgery. Therefore, reorganization of the speech system took time. Activation of right-sided homologues of the speech areas remained in all patients for up to a year. Simultaneous activation of right-sided homologues of both speech areas, the Broca's and Wernicke's areas, was detected more often in patients with frontal lobe tumors than in those with temporal lobe tumors. No additional activation foci in the left hemisphere were found at the thresholds used to process fMRI data. Recovery of the speech function, to a certain degree, occurred in all patients, but no clear correlation with fMRI data was found. CONCLUSION: Complex fMRI and neuropsychological studies in 20 patients after resection of frontal and temporal lobe tumors revealed individual features of speech system reorganization within one year follow-up. Probably, activation of right-sided homologues of the speech areas in the presence of left hemisphere tumors depends not only on the severity of speech disorder but also reflects individual involvement of the right hemisphere in enabling speech function. This is confirmed by right-sided activation, according to the fMRI data, in right-sided patients without aphasia and, conversely, the lack of activation of right-sided homologues of the speech areas in several patients with severe postoperative speech disorders during the entire follow-up period.

[The phenomenon of long-term survival in glioblastoma patients. Part I: the role of clinical and demographic factors and an IDH1 mutation (R 132 H)]. / Fenomen dlitel'noi vyzhivaemosti patsientov s glioblastomami. Chast' I: rol' kliniko-demograficheskikh faktorov i mutatsii IDH1 (R 132 H).

The median overall survival of glioblastoma patients is about 15 months. Only a small number of patients survive 3 years. The factors of a favorable prognosis for the 'longevity phenomenon' in glioblastoma patients are not fully understood. OBJECTIVE: to determine the occurrence rate of long-living patients with glioblastomas, identify clinical predictors of a favorable prognosis, and identify the presence and prognostic significance of an IDH1 mutation. MATERIAL AND METHODS: Among 1494 patients operated on for glioblastoma at the Burdenko Neurosurgical Institute from 2007 to 2012, there were 84 (5.6%) patients who lived more than 3 years after primary surgery. In all the cases, histological specimens were reviewed, and immunohistochemical detection of a mutant IDH1 protein was performed. Overall survival was calculated from the time of first surgery to the date of the last consultation or death, and the recurrence-free period was calculated from the time of first surgery to MRI-verified tumor progression. RESULTS: The median age of long-living patients with glioblastoma was 45 years (19-65 years). All tumors were located supratentorially. The median Karnofsky performance status score at the time of surgery was 80 (range, 70-100). All patients underwent microsurgical resection of the tumor, followed by chemoradiotherapy. The median recurrence-free period was 36 months (5-98 months). Overall survival of 48, 60, and 84 months was achieved in 23, 15 and 6% of patients, respectively. Among 49 specimens available for the IDH1 analysis, 14 (28.6%) specimens had a mutant protein. There was no significant difference in survival rates in patients with positive and negative results for IDH1 (44.1 vs. 40.8 months; p>0.05). CONCLUSION: The significance of various factors that may be predictors of a favorable course of the disease is discussed in the literature. This work is the first part of analysis of prognostically significant factors positively affecting overall survival of glioblastoma patients. In our series, the predictors of a favorable prognosis for long-living patients with the verified diagnosis of glioblastoma were as follows: young age, the supratentorial location of the tumor, a high Karnofsky score before surgery, and tumor resection. In our series, we used immunohistochemical tests and found no prognostic significance of the IDH1 gene mutation; further analysis will require application of direct sequencing. We plan to study other morphological and molecular genetic features of tumors, which explain prolonged survival of glioblastoma patients, as well as the role of various types of combined chemoradiation treatment.

[Long association tracts of the human white matter: an analysis of 18 hemisphere dissections and in vivo HARDI-CSD tractography]. / Dlinnye assotsiativnye provodyashie puti belogo veshchestva golovnogo mozga cheloveka: analiz dissektsii 18 polusharii i HARDI-CSD traktografii in vivo.

BACKGROUND: Anatomy of the conduction tracts of the cerebral cortex has been studied for a long time. Invention of diffusion tensor tractography renewed interest in this subject. The objectives of this work were to develop and improve protocols for dissection of the long association tracts of the human brain with studying the features of their segmentation, topography, and variability, compare the obtained data with the MR tractography data, and prepare for further clinical and anatomical studies. MATERIAL AND METHODS: We used 18 cerebral hemispheres (from 10 males and 8 females; 9 left and 9 right hemispheres). The mean age of cadavers was 68 years. Specimen were fixated in accordance with the Klingler technique. Immediately after collection, specimens were placed in a 10% formalin solution for at least 4 weeks. After that, the pia was removed; specimens were frozen at -20 °C for a week and then unfrozen in a 96% ethanol solution for a day. We performed 10 lateral dissections, 2 lateral dissections with isolation of the frontal aslant tract, 2 basal dissections, 1 combined basolateral dissection, 2 frontal dissections, and 1 medial dissection. At the time of dissection and after it, specimens were stored in a 96% ethanol solution. Modified, disposable, therapeutic wooden spatulas were used for manipulations. A microscope (magnification of 6-40x) was used in 2 lateral and 2 basal dissections. MR tractography (HARDI-CSD) was carried out in 5 healthy volunteers using a GE Signa HDxt MRI scanner a field strength of 3.0 T. RESULTS: We clearly identified the following fascicles: the arcuate fascicle (AF) and superior longitudinal fascicle (SLF) in 6/6 hemispheres on the right and in 5/6 hemispheres on the left, the inferior longitudinal fascicle (ILF) in 3/6 hemispheres on the left and in 4/6 hemispheres on the right, the uncinate fascicle (UF) in 4/4 hemispheres on the left and in 4/4 hemispheres on the right, and the inferior fronto-occipital fascicle (IFOF) in 4/4 hemispheres on the left and in 3/4 hemispheres on the right. Identification was less successful in the case of the frontal aslant tract (FAT) in 1/2 hemispheres on the left and in 0/2 hemispheres on the right. The used technique failed to identify the vertical occipital fascicle (VOF) of Wernicke, a segment of the superior longitudinal fascicle SLF I, and the middle longitudinal fascicle (MdLF). The MR tractography HARDI-CSD data were compared with the dissection data. We described in detail segmentation of the superior longitudinal, arcuate, and inferior fronto-occipital fascicles. Contradictory data were obtained for the superior longitudinal fascicle: a two-segment structure (SLFh and SLFv) was found in most (10/12) specimens, while a three-segment structure was revealed in the other (2/12) specimens (identified SLF II and SLF III). In the arcuate fascicle, the ventral and dorsal segments were successfully identified in 2/12 cases (1 left and 1 right), whereas identification failed in the other cases. During dissection of the inferior fronto-occipital fascicle, we could identify its surface layer in 1 of 8 cases (left) and its deep layer in one more case (left). CONCLUSION: Examination of the long association tracts using the Klingler technique has significant limitations in the fiber intersection areas (sagittal striatum). The frontal aslant tract was least studied; we proposed a special anterior dissection technique for its isolation. The superior longitudinal fascicle can have both the two-segment (10/12) and three-segment (2/12) structure. Investigation of the segmental anatomy of the long association tracts will be continued in further dissections. When planning neurosurgical interventions in the projection areas of the long association tracts, both preoperative HARDI-tractography and anatomical dissections ex vivo, based on the proposed protocols, can be recommended for the operating surgeon to master a three-dimensional picture of the tract topography.

[Diffusion tensor imaging tractography and intraoperative neurophysiological monitoring in surgery of intracranial tumors located near the pyramidal tract].

BACKGROUND: Practical application of methods for intravital examination of the brain pathways, such as preoperative diffusion tensor imaging (DTI) tractography and intraoperative neurophysiological monitoring, facilitates safer resection of intracranial tumors located near the pyramidal tracts (PTs). PURPOSE: The study purpose was to investigate the relationships between intracerebral tumors of different histological nature and the pyramidal tract based on preoperative DTI tractography and various methods of intraoperative neurophysiological monitoring for intraoperative identification of the pyramidal tract, depending on different variants of the topographo-anatomic relationships between the pyramidal fascicle and the tumor. MATERIAL AND METHODS: The study included 29 patients with supratentorial tumors of a different histological structure. Of these, 2 patients had grade I tumors, 8 patients had grade II tumors, 4 patients had grade III tumors, 11 patients grade IV tumors, and 4 patients had brain metastases. The patients underwent preoperative DTI tractography with PT reconstruction and evaluation of the topographo-anatomic relationships between the pyramidal tract and the tumor (tract: intact, infiltrated, displaced). Neurophysiological monitoring (direct electrical stimulation in 24 patients and transcranial motor evoked potentials in 26 patients) was used during surgery. The strength of stimulating current for direct stimulation was varied from 10 to 30 mA. Postoperatively, the motor function was evaluated by using a 5-score scale, and the data were compared to the preoperative data. RESULTS: According to preoperative DTI tractography in patients with grade I-II gliomas, the corticospinal tracts were infiltrated in 2 cases, displaced in 3 cases, and intact in 5 cases. In patients with grade III-IV gliomas and metastases, the tracts were infiltrated in 8 cases, displaced in 4 cases, and intact in 7 cases. Motor responses evoked by direct electrical stimulation were obtained in 5 out of 6 patients with the pyramidal tract displaced by the tumor and in 7 out of 8 patients with the tract infiltrated by the tumor. In the case of the intact tract, the PT to tumor distance and the stimulus strength play an important role: responses were obtained in 4 out of 10 patients. In the case of transcranial motor evoked potentials (TCMEPs), no dynamics of the potential amplitude was detected in 17 out of 26 patients during surgery; a reduced TCMEP amplitude was detected in 9 patients. CONCLUSION: 1. Patients with an infiltrated or displaced pyramidal tract had significantly more often hemiparesis before surgery and aggravation of hemiparesis after the surgery compared to patients with an intact tract. 2. In the case of direct electrical stimulation of the PT, motor responses (according to preoperative DTI tractography) were significantly more often observed for the pyramidal tract infiltrated and displaced by the tumor. 3. A reduction in the motor neurologic deficit in the postoperative period was significantly more often observed for application of a larger current strength during direct electrical stimulation. 4. Persistence of the TCMEP amplitude during surgery is a reliable predictor for no aggravation of the motor neurological deficit after surgery. Postoperative aggravation of hemiparesis was significantly more often observed when TC MEPs decreased during surgery.

[Clinical guidelines for the use of intraoperative fluorescence diagnosis in brain tumor surgery].

In this paper, we present a review of current literature on the application of intraoperative fluorescence diagnosis and fluorescence spectroscopy using 5-aminolevulinic acid in surgery for various types of brain tumors, both alone and in combination with other neuroimaging methods. Authors' extensive experience with these methods allowed them to develop a set of clinical guidelines for the use of intraoperative fluorescence diagnosis and fluorescence spectroscopy in surgery of brain tumors.

[The structure of activation of the language zone in patients with intracerebral tumors according to fMRI with respect to tumor location and the functional asymmetry profile].

MATERIAL AND METHODS: A total of 50 patients were examined prior to surgical resection of intracranial tumors of the temporal and frontal lobes. Left-sided tumors were observed in 33 patients and right-sided tumors were observed in 17 patients. The functional asymmetry profile was determined using self-assessment, the Annet questionnaire, and the dichotic listening task. Twelve patients were left-handers or retrained left-handers and the remaining 38 patients were right-handers. FMRI examination was carried out on a 3.0 T SignaHDxt magnetic resonance tomograph (GE). The standard language block design paradigm was used in the study. We used the following tests: 1) recitation of months in reverse order; 2) generation of nouns according to the initial letters shown on the screen (K, M, L, N, P, C); 3) generation of verbs according to simple actions shown on the screen; 4) producing sentences using nouns shown on the screen; 5) listening to text through headphones. Data were processed using the standard BrainWave PA software (General Electric). Z-test was used in the range from 6 to 9. In all the studies, p<0.001. Statistical data processing included the nonparametric Spearman's test to determine the correlation between lateralization of the detected activation zone under speech load and tumor location (tumor is adjacent to the language zone, invades the language zone, or is located far from the language zone), as well as left- or right-handedness. RESULTS: Among 16 patients (right-handers and 2 left-handers) the activation of language zones was observed only on the left side; in one left-handed patient, Broca's area was detected only on the right side. In other patients (including right-handers with right-sided tumors), lateralization of language zones was different, including bilateral. Statistical processing revealed that bilateral activation of both Broca's and Wernicke's areas was more frequently observed in left-handers. Broca's area was more frequently detected on the left side in the presence of a distant tumor, while this trend did not apply for Wernicke's area. CONCLUSION: Localization of activation of Broca's area is more dependent on tumor location, while it depends on personal characteristics of an individual in the case of Wernicke's area.

[Glioblastoma metastases: a literature review and a description of six clinical observations].

INTRODUCTION: since the 1990s, the literature has described cases of glioblastoma metastases with the development of foci located at a distance from the primary tumor. However, the pathogenesis of this process remains unclear until the end. This focus is believed to result, on the one hand, from tumor metastasis from the primary site and, on the other hand, from multifocal growth. This article presents a literature review and a description of clinical observations of patients with glioblastoma metastases. MATERIAL AND METHODS: The study included 6 patients (1 female and 5 males) with brain glioblastomas who received treatment at the Burdenko Neurosurgical Institute (5 patients) and the Department of Neurosurgery of the Research Center of Neurology (1 patient) in the period from 2010 to 2014. Neurophysiological control was used if the tumor was localized near the eloquent cortical areas and pathways; 4 of 6 patients were operated on using the methods of intraoperative fluorescence diagnosis (5-ALA agent--Alasens). RESULTS: Four patients had metastases within one hemisphere, two had metastases in the contralateral hemisphere in the period of 5 to 18 months after the first operation. The primary tumor site was located near the ventricular system in two patients. In one patient, the lateral ventricle was opened during the first operation. In another patient, the prepontine cistern was opened during the first operation. In two patients, the primary tumor site was located at a distance from the lateral ventricles, however, the tumor was located near them during recurrence. Based on metabolic navigation, fluorescence of the tumor was observed in the four patients during both the first and repeated operations. CONCLUSIONS: The close relationship between primary glioblastomas and metastases and the cerebrospinal fluid circulation pathways may confirm the fact of dissemination of tumor cells with cerebrospinal fluid flow. In our opinion, there should be an increased suspicion of the possibility for metastases of glioblastomas that are closely associated with the cerebrospinal fluid circulation pathways. Metabolic navigation with 5-ALA is effective both during primary surgery in patients with glioblastomas and during resection of glioblastoma metastases.

[Review of surgical treatment of insular gliomas: challenges and opportunities].

Intracerebral tumors of the insular lobe are quite frequent, however treatment of patients with this pathology still remains a challenging and controversial issue of neurosurgery. First of all, this is associated with the localization of tumors in the area of eloquent anatomical structures: M1--M2 segment of the middle cerebral artery, lenticulostriate arteries, basal ganglia, and internal capsule, which causes a high rate of postoperative complications in these patients. Most insular tumors are amenable for resection with a reasonable rate of postoperative complications, although most of the surgery-related complications resulting in substantial deficits are due to lesions of eloquent anatomical structures located in this compact anatomical space. Therefore, the aim of this work was to analyze the literature regarding the issues of clinical presentation, diagnosis, and aspects of surgical treatment of insular tumors.

[The long-associative pathway of the white matter: modern view from the perspective of neuroscience].

This review presents basic information about white matter tracts of the human brain, with a special emphasis being placed on long associative fibers (superior and inferior longitudinal fascicles, inferior frontooccipital fascicles, fasciculus arcuatus and fasciclus uncinatus): their structure, history, functions, methods of preoperative and intraoperative identification during neurosurgical operations. Neurological symptoms caused by a damage to each of the above-described long associative fiber are described. There is a detailed analysis of methods of neuropsychological testing and neurophysiological identification in white matter fiber tract mapping in focal brain lesions.

[Rare cases of reflex epilepsy in patients with gliomas of the left hemisphere].

We present the cases of symptomatic reflex epilepsy in patients with left hemisphere tumors. The first case: a 23-year-old man has had tonic-clonic seizures of the tongue with rare secondary localization over the past several months. The seizures were caused by intense tongue movements, in particular rightward and leftward (when having chewing gum or a candy in his mouth), but not during speech production or eating. MRI scanning detected a small tumor in the lower segments of the central gyrus. It was found during the surgery under electrophysiological control that the tumor (Gr II astrocytoma) resided in the zone corresponding to the right half of the tongue and included this zone. The tumor was partially resected. The second patient, a 52-year-old man, has been suffering from generalized seizures since 1998. The seizures were caused by intense verbal load, in the beginning of spontaneous speech and subsequently when the patient was listening to others' speech or was writing. Spontaneous seizures emerged when the patient stopped taking his anti-seizure medications unilaterally. MRI showed glioma in the posterior segments of the left temporal lobe. The patient underwent radiation and chemotherapy. In 2013, the patient's condition worsened (right-sided hemiparesis and severe speech impairment emerged); the tumor was partially resected and an extensive cyst was opened. The third patient, a 38-year-old man with Gr III astrocytoma in the left insula with past medical history of spontaneous vegetative seizures, had only a seizure anticipation caused by strong smells. All the patients were prescribed chemo-, radiation, and anti-seizure therapy.