Grey and white matter substrates of action naming.

Despite a persistent interest in verb processing, data on the neural underpinnings of verb retrieval are fragmentary. The present study is the first to analyze the contributions of both grey and white matter damage affecting verb retrieval through action naming in stroke. We used voxel-based lesion-symptom mapping (VLSM) with an action naming task in 40 left-hemisphere stroke patients. Within the grey matter, we revealed the critical involvement of the left precentral and inferior frontal gyri, insula, and parts of basal ganglia. An overlay of white matter tract probability masks on the VLSM lesion map revealed involvement of left-hemisphere long and short association tracts with terminations in the frontal areas; and several projection tracts. The involvement of these structures is interpreted in the light of existing picture naming models, semantic control processes, and the embodiment cognition framework. Our results stress the importance of both cortico-cortical and cortico-subcortical networks of language processing.

Neural mechanisms of two different verbal working memory tasks: A VLSM study.

Currently, a distributed bilateral network of frontal-parietal areas is regarded as the neural substrate of working memory (WM), with the verbal WM network being more left-lateralized. This conclusion is based primarily on functional magnetic resonance imaging (fMRI) data that provides correlational evidence for brain regions involved in a task. However, fMRI cannot differentiate the areas that are fundamentally required for performing a task. These data can only come from brain-injured individuals who fail the task after the loss of specific brain areas. In addition to the lack of complimentary data, is the issue of the variety in the WM tasks used to assess verbal WM. When different tasks are assumed to measure the same behavior, this may mask the contributions of different brain regions. Here, we investigated the neural substrate of WM by using voxel-based lesion symptom mapping (VLSM) in 49 individuals with stroke-induced left hemisphere brain injuries. These participants completed two different verbal WM tasks: complex listening span and a word 2-back task. Behavioral results indicated that the two tasks were only slightly related, while the VLSM analysis revealed different critical regions associated with each task. Specifically, significant detriments in performance on the complex span task were found with lesions in the inferior frontal gyrus, while for the 2-back task, significant deficits were seen after injury to the superior and middle temporal gyri. Thus, the two tasks depend on the structural integrity of different, non-overlapping frontal and temporal brain regions, suggesting distinct neural and cognitive mechanisms triggered by the two tasks: rehearsal and cue-dependent selection in the complex span task, versus updating/auditory recognition in the 2-back task. These findings call into question the common practice of using these two tasks interchangeably in verbal WM research and undermine the legitimacy of aggregating data from studies with different WM tasks. Thus, the present study points out the importance of lesion studies in complementing functional neuroimaging findings and highlights the need to consider task demands in neuroimaging and neuropsychological investigations of WM.

[Prognostic significance of clinical-anthropometric, biochemical, metabolic, vascular-inflammatory and molecular-genetic markers in the development of the first ischemic stroke]. / Prognosticheskaia znachimost' kliniko-antropometricheskikh, biokhimicheskikh, metabolicheskikh, sosudisto-vospalitel'nykh i molekuliarno-geneticheskikh markerov v razvitii pervogo ishemicheskogo insul'ta.

AIM: To study the relationship between clinical-anthropometric, biochemical, metabolic, vascular-inflammatory, molecular-genetic parameters and the development of the first ischemic stroke, and to develop a prognostic model for determining the probability of its occurrence. MATERIAL AND METHODS: The study included 196 first ischemic stroke patients and 119 healthy people matched for age, place of residence and nationality to the group of patients. The main anthropometric, clinical, biochemical, metabolic parameters and markers of vascular inflammation and endothelial dysfunction were assessed. Single nucleotide polymorphisms of IL8, ADIPOQ, ADIROR, APOB, APOC-IV, BDNF, GRM3 genes were genotyped. RESULTS: Weight, BMI, waist circumference, homocysteine, insulin, adiponectin, cystatin C, ApoA1, Apo B, CHOL, HDL, LDL, TG, CRB-sh, glucose, uric acid, IL-1b, IL-4, IL-6, IL-8, TNF-a, VEGF-A were significantly associated with the first ischemic stroke. CONCLUSION: Based on the data obtained in this study, a probability model for the development of the first ischemic stroke was obtained. Of all the parameters studied, diabetes mellitus, adiponectin, Apo A1, IL-4 made the largest contribution to the probability of the first ischemic stroke.

[A role of genetic factors and related disorder of the folate cycle in ischemic stroke]. / Rol' geneticheskikh faktorov i svyazannykh s nimi narushenii folatnogo tsikla v razvitii ishemicheskogo insul'ta.

AIM: To study a role of MTHFR mutations and their associations with the disturbances of basic parameters of the folate cycle in the development of ischemic stroke (IS). MATERIAL AND METHODS: Fifty-one post-stroke patients, 26 women and 25 men, aged from 29 to 87 years, were included in the study. The control group consisted of 47 healthy people, 23 women and 24 men, aged from 30 to 83 years. MTHFR: rs1801131 and rs1801133 polymorphisms were genotyped. Contents of folate, B12 and homocysteine were measured. RESULTS: The risk group which was characterized by the presence of risk variants of rs1801131 and rs1801133 polymorphisms, changes in the parameters of the folate cycle (the decrease in B12 concentration (≤500 pg/ml)) in the combination with hyperhomocysteinemia (≥13 mcmol/L) was identified. CONCLUSION: The disturbance of the folate cycle, including gene variations, is a basic pathogenetic link in the development of cerebral atherosclerosis and associated cerebrovascular diseases.

[Prognostic criteria of rehabilitation of patients with ischemic stroke].

AIM: To identify prognostic criteria of the restoration of movement in patients after acute disturbance of cerebral blood circulation. MATERIAL AND METHODS: Results of clinical examination of 82 patients after the acute disturbance of blood circulation in the left hemisphere were analyzed in the Center for Speech Pathology and Neurorehabilitation. The degree of hemiparesis was compared with disease history data, results of electroencephalography, ultrasound and transcranial dopplerography, computed tomography and biochemical study. RESULTS AND CONCLUSION: The volume of lesion <50 cm3 which was not located in occipital regions, the volume of lesion from 50 to 100 cm3 with the disturbance of blood circulation only in one arterial system (carotid or cerebral) and residual or moderate pathological changes in electrical activity were characteristic of favorable prognosis of rehabilitation. Poor prognosis was associated with the volume of lesion >100 cm3 with concomitant disturbance of blood circulation in two arterial systems (both carotid and cerebral), marked and moderate pathological changes in electrical activity and the occipital localization of the lesion regardless of its volume.

[Neurorehabilitation of patients after stroke and brain injury]. / Neiroreabilitatsiia bol'nykh s posledstviiami insul'ta i cherepno-mozgovoi travmy.

Cerebral vascular diseases, traumatic brain injuries are frequent causes of fatality and severe disability. A complex of measures seems to be perspective to restore the brain functions impaired due to the focal brain lesion. Main stages of the formation of neurorehabilitation as independent discipline are considered. The progress in this field and the problems that need to be resolved are analyzed. The contribution of Russian scientists (neurologists, neurosurgeons, psychologists) to the development of neurorehabilitation is highlighted.