Faculty Bibliography

In the present study, we combine linguistic annotation of oral texts in Russian with the registration of BOLD signal in functional MRI experiments to determine how and where semantic categories are represented in the human brain. Using the same stimuli material, we also analyze the differences in cortical activation in three thematic domains: description of nature, description of working principles of technical devices and more self-referential texts, addressing the question of human identity in conflict situations. We discuss methodological problems within the two approaches (microanalysis and macroanalysis) to study brain activation in natural conditions, i.e. under a continuous speech flow. Within the thematic domain studies, only minimally significant differences in brain activation were registered during the listening to texts from the three thematic groups. This outcome leads to the conclusion that the approach of thematic group contrasts (cognitive subtraction methodology) is not sufficient to study the mechanisms of text comprehension, and should be replaced by the modeling of multidimensional representations of semantic categories in time. Within the semantic category approach, we describe the neurolinguistic process of text understanding as the activation of 15 clusters responsible for semantic categories (e.g. "Conflict", "Mental", "Social"). Our data demonstrate that the clusters are widely distributed across the human brain. In contrast to the previous studies, we suggest that deep subcortical structures are involved in the processing of certain categories as well. The observed lateralization of category processing underlines the involvement of the right hemisphere in the processing of meaning.

Background:Action observation (AO) relies on the mirror neuron system (MNS) and has been proposed as a rehabilitation tool in Parkinson's disease (PD), in particular for gait disorder such as freezing of gait (FOG). In this study, we aimed to explore the brain functional correlates of the observation of human gait in PD patients with (FOG+) and without (FOG-) FOG and to investigate a possible relationship between AO-induced brain activation and gait performance. Methods:Fifty-four participants were enrolled in the study (15 PD FOG+; 18 PD FOG-; 21 healthy subjects (HS)) which consisted of two tasks in two separate days: (i) gait assessment and (ii) task-fMRI during AO of gait. Differences between patients with PD (FOG+ and FOG-) and HS were assessed at the level of behavioral and functional analysis. Results:. Patients with PD present a reduced functional activity during AO of gait, especially if FOG+. A baseline knowledge of the neural correlates of AO of gait in the clinical routine "on" status would help for the design of future AO rehabilitative interventions.

Background/UNASSIGNED:Spine surgeons encounter occasional complex cerebrospinal fluid fistulas/dural tears (CSF/DT) during lumbar spinal surgery. In some cases, these leaks are found during the index procedure, but others may appear postoperatively, or in the course of successive procedures. Here we asked, whether these complex CSF fistulas/DT could be more readily repaired utilizing a "bone suture anchor" technique, particularly where there is no residual dural margin/remnant. Methods/UNASSIGNED:With the combined expertise of the orthopedist and neurosurgeon, mini/micro bone suture anchors, largely developed for hand surgery, facilitated repair of complex DT occurring during lumbar spine surgery. This technique was utilized to suture in place fascia, periosteal, or muscle grafts, and was followed by the application of microfibrillar collagen, and a fibrin sealant. Results/UNASSIGNED:This mini/micro suture anchor technique has now been utilized to repair multiple significant intraoperative and/or postoperative recurrent DT, largely avoiding the need to place lumbar drains and/or lumbo- peritoneal shunts. Conclusions/UNASSIGNED:Here, we reviewed how to directly suture dural grafts utilizing a mini/micro bone suture anchor technique to repair complex intraoperative primary/recurrent DT occurring during lumbar spine surgery. The major advantages of this technique, in addition to obtaining definitive occlusion of the DT, largely avoids the need to place lumbar drains and/or lumbo-peritoneal shunts with their attendant risks and complications.

Seizures are an infrequent and serious neurological complication of SARS-CoV-2 infection, with limited data describing the etiology and the clinical context in which these occur or the associated electrographic and imaging findings. This series details four cases of seizures occurring in patients with COVID-19 with distinct time points, underlying pathology, and proposed physiological mechanisms. An enhanced understanding of seizure manifestations in COVID-19 and their clinical course may allow for earlier detection and improved patient management.