Maria Nazarova

The use of a systematic approach to the study of the etiology of a certain pathology makes it possible to improve the understanding of its pathogenesis, as well as to develop more effective diagnostic and therapeutic approaches, including improving the prediction of its risk. Within this review, we will consider such an area of interdisciplinary research as neurocardiology, which studies the brain-heart axis. Examples of cardiovascular diseases associated with organic and functional disorders of this axis will be considered, as well as the prospects for research in this area and their translational significance for clinical medicine.

The spatial accuracy of transcranial magnetic stimulation (TMS) may be as small as a few millimeters. Despite such great potential, navigated TMS (nTMS) mapping is still underused for the assessment of motor plasticity, particularly in clinical settings. Here, we investigate the within‐limb somatotopy gradient as well as absolute and relative reliability of three hand muscle cortical representations (MCRs) using a comprehensive grid‐based sulcus‐informed nTMS motor mapping. We enrolled 22 young healthy male volunteers. Two nTMS mapping sessions were separated by 5–10 days. Motor evoked potentials were obtained from abductor pollicis brevis (APB), abductor digiti minimi, and extensor digitorum communis. In addition to individual MRI‐based analysis, we studied normalized MNI MCRs. For the reliability assessment, we calculated intraclass correlation and the smallest detectable change. Our results revealed a somatotopy gradient reflected by APB MCR having the most lateral location. Reli...

Arthrogryposis multiplex congenita (AMC) has recently drawn substantial attention from researchers and clinicians. New effective surgical and physiotherapeutic methods have been developed to improve the quality of life of patients with AMC. While it is clear that all these interventions should strongly rely on the plastic reorganization of the central nervous system, almost no studies have investigated this topic. The present study demonstrates the feasibility of using magnetoencephalography (MEG) to investigate brain activity in young AMC patients. We also outlined the general challenges and limitations of electrophysiological investigations on patients with arthrogryposis. We conducted MEG recordings using a 306-channel Elekta Neuromag VectorView system during a cued motor task performance in four patients with arthrogryposis, five normally developed children, and five control adults. Following the voice command of the experimenter, each subject was asked to bring their hand towar...

Background and Purpose: Despite continuing efforts in the multimodal assessment of the motor system after stroke, conclusive findings on the complementarity of functional and structural metrics of the ipsilesional corticospinal tract integrity and the role of the contralesional hemisphere are still lacking. This research aimed to find the best combination of motor system metrics, allowing the classification of patients into 3 predefined groups of upper limb motor recovery. Methods: We enrolled 35 chronic ischemic stroke patients (mean 47 [26–66] years old, 29 [6–58] months poststroke) with a single supratentorial lesion and unilateral upper extremity weakness. Patients were divided into 3 groups, depending on upper limb motor recovery: good, moderate, and bad. Nonparametric statistical tests and regression analysis were used to investigate the relationships among microstructural (fractional anisotropy (FA) ratio of the corticospinal tracts at the internal capsule (IC) level (classic...

Besides stimulus intensities and interstimulus intervals (ISI), the electric field (E-field) orientation is known to affect both short-interval intracortical inhibition (SICI) and facilitation (SICF) in paired-pulse transcranial magnetic stimulation (TMS). However, it has yet to be established how distinct orientations of the conditioning (CS) and test stimuli (TS) affect the SICI and SICF generation. With the use of a multi-channel TMS transducer that provides electronic control of the stimulus orientation and intensity, we aimed to investigate how changes in the CS and TS orientation affect the strength of SICI and SICF. We hypothesized that the CS orientation would play a major role for SICF than for SICI, whereas the CS intensity would be more critical for SICI than for SICF. In eight healthy subjects, we tested two ISIs (1.5 and 2.7 ms), two CS and TS orientations (anteromedial (AM) and posteromedial (PM)), and four CS intensities (50, 70, 90, and 110% of the resting motor thre...

The spatial accuracy of TMS may be as small as a few millimeters. Despite such great potential, navigated TMS (nTMS) mapping is still underused for the assessment of motor plasticity, particularly in clinical settings. Here we investigate the within-limb somatotopy gradient as well as absolute and relative reliability of three hand muscle cortical representations (MCRs) using a comprehensive grid-based sulcus-informed nTMS motor mapping. We enrolled 22 young healthy male volunteers. Two nTMS mapping sessions were separated by 5-10 days. Motor evoked potentials were obtained from abductor pollicis brevis (APB), abductor digiti minimi, and extensor digitorum communis. In addition to individual MRI-based analysis, we studied MNI normalized MCRs. For the reliability assessment, we calculated intra-class correlation and the smallest detectable change. Our results revealed a somatotopy gradient reflected by APB MCR having the most lateral location. Reliability analysis showed that the com...

The use of the MRI-navigation system ensures accurate targeting of TMS. This, in turn, results in TMS motor mapping becoming a routinely used procedure in neuroscience and neurosurgery. However, currently, there is no standardized methodology for assessment of TMS motor-mapping results. Therefore, we developed TMSmap-free standalone graphical interface software for the quantitative analysis of the TMS motor mapping results (http://tmsmap.ru/). In addition to the estimation of standard parameters (such as the size of cortical muscle representation and the center of gravity location), it allows estimation of the volume of cortical representations, excitability profile of the cortical surface map, and the overlap between cortical representations. The input data for the software includes the coordinates of the coil position (or electric field maximum) and the corresponding response in each stimulation point. TMSmap has been developed for versatile assessment and comparison of TMS maps r...

ABSTRACT OBJECTIVE: To analyze clinical and neuroimaging data in patients with neck pain and headache as the only manifestation of the internal carotid artery (ICA) dissection (ICAD) and vertebral artery (VA) dissection (VAD). MATERIAL AND METHODS: One hundred and sixty-one patients (mean age - 37,4±4,99 years, 84 women, 52%) with cervical artery dissection (CAD) verified by magnetic resonance imaging (MRI) were enrolled. Neck pain and headache were the only CAD manifestation in 33 patients (mean age 37,3±7,4 yars, 28 women, 85%). RESULTS: The localization of the dissections in these patients was the following: one VA (15 patients), two VA (9), one ICA (7), two ICA (1), one ICA + two VA (1). The whole number of dissected arteries was 45: extracranial localization - 38, extra- intracranial - 6, intracranial - 1. Dissection led to stenosis of the arterial lumen in 41 arteries, to occlusion - in 2 and to dual lumen in 2 arteries. Small aneurism was found in 4 arteries. Combination of headache and the neck pain was observed in 26 out of 33 patients (79%), the only headache in 4 patients, the only neck pain in 3 patients. Along with this, 9 out of 24 VAD patients had the shoulder and/or arm pain. Headache in VAD patients was located more often in the occipital region (18 out of 24) that had never been observed in ICAD patients (p=0.0009). Fronto-temporal pain was observed more often in ICAD patients (5 out of 8 patients) than in VAD (2 out of 24 patients) (p=0.003). Neck pain in all VAD patients in comparison with 3 out of 8 ICAD patients had posterior localization (р=0,007). Anterolateral neck pain was observed in 4 out of 8 ICAD patients and in no patients with VAD (р=0.0009). The pain appearance was abrupt in all ICAD patients and most of the VAD patients. In 8 VAD patients the pain has been increasing during several hours. The pain intensity was severe in 19 patients, moderate in 12 and mild in 2. The characteristics of the pain were as following: constrictive/dull (26 patients), throbbing (1 patient) or combined (6 patients). Pain was increasing in a stepwise manner during the first days in 14 out of 24 VAD patients and in no one of ICAD patients (р=0.008). The mean pain duration period was 31,8 ±15,7 days. Pain relief drugs were ineffective or had a short effect in 97% of patients. CONCLUSION: Isolated pain is more characteristic for women with VAD. Usually pain is presented as a combination of headache and neck pain. Pain localization, mode of appearance and the course are different in VAD and ICAD. The rarity of occlusion among patients with "pain-only" manifestation let to suggest that the intramural hematoma in this group of patients spreads to the adventitia that can reflect media weakness. Arterial wall changes underlying its weakness seem to be sex-hormone dependent taking into consideration the high predominance of women in CAD manifested by isolated pain.

Recently, transcranial alternating current stimulation (tACS) has emerged as a tool to enhance human cognitive processes. Here, we provide a brief summary of the rationale behind tACS-induced effects on task-relevant brain oscillations and associated cognitive functions and review previous studies in young subjects that have applied tACS in cognitive paradigms. Additionally, we present pilot data where we administered theta-tACS (6 Hz) over the temporoparietal cortex and a supraorbital reference for 20 min during implicit language learning in healthy young (mean/SD age: 22/2) and older (mean/SD age: 66/4) adults, in a sham-controlled crossover design. Linear mixed models revealed significantly increased retrieval accuracy following tACS-accompanied associative learning, after controlling for session order and learning success. These data provide the first implementation of tACS during cognitive performance in older adults and support recent studies suggesting that tACS in the theta ...

Background: Patients beginning an outpatient rehabilitation program often do not understand medications, good blood pressure (BP) control, and monitoring and recording of BPs Methods: An educational curriculum based on AHA guidelines and AHA Life’s Simple 7’s program was designed to improve patient understanding of medications, cardiovascular risk factors, and BP monitoring. Results: 51 consecutive patients, (27 men, 24 women, ages 41-90) with admit NIHSS 0-16 treated from 12/2011 to 7/2013 had an average of 9.6(0-21) NP visits with calls to MD about BP meds in 16%. On rehab admit, 6 patient/caregivers reported AHA recommendations for normal BP, and 7 patients/caregivers checked and recorded BPs. After NP sessions, 71%(36/51) patients checked and recorded BPs independently, 29% with assist. 46 patients received an average of 16.5 PT sessions, with BPs taken pre, during, and after exercise. Among 647 pre-exercise BPs, 37% were in AHA normal range(<120/80). 32% in mild (121-139/81-...

To compare demographic, clinical, and imaging characteristics of patients with internal carotid artery dissection (ICAD) and vertebral artery dissection (VAD) in a Russian population. One hundred fifty-two consecutive patients (74 males, 49%; mean age - 37.0±10.3 years) with cervical artery dissection (ICAD - 85 patients, 56%; VA - 62 patients, 41%; ICA+VA - 5 patients - 3%) verified by MRI/MRA were studied. Five patients with both ICAD and VAD were excluded from analysis. Patients with ICAD more often were men (63%, p<0.0001), while patients with VAD were women (69%, p<0.0001), age distribution was similar (37.4±11.2 and 36.2±9.4 years, p>0.05). The main precipitating events for VADs were neck movements, prolonged static turning of the head, physical exertion (57% vs 28% in ICAD, p=0.0009). Head trauma within the previous month was more often reported by ICAD patients than VAD patients (21% vs 7%, p=0.0295). Clinically ICADs more frequently manifested by ischemic stroke (I...

Skin and muscles biopsy specimens of a patient harboring A3243G mutation in mitochondrial DNA, with dissection of internal carotid and vertebral arteries, associated with MELAS were studied using histochemical and electron-microscopy techniques. Ragged red fibers, regional variability of SDH histochemical reaction, two types of morphologically atypical mitochondria and their aggregation were found in muscle. There was correlation between SDH histochemical staining and number of mitochondria revealed by electron microscopy in muscle tissue. Similar mitochondrial abnormality, their distribution and cell lesions followed by extra-cellular matrix mineralization were found in the blood vessel walls. In line with generalization of cytopathy process caused by gene mutation it can be supposed that changes found in skin and muscle microvessels also exist in large cerebral vessels causing the vessel wall "weakness", predisposing them to dissection.

Spontaneous cerebral artery dissection is a common cause of ischemic stroke in young adults and children. Dissection is often related to arterial wall weakness the cause of which is unknown. An aim of the present paper was to carry out an electron microscopic study of skin arteries and arterioles in patients with ischemic stroke caused by cerebral artery dissection. Skin biopsy samples from 3 patients (2 men and one women, 15, 25 and 43 years of age, respectively) were studied. Electron microscopy revealed changes of endothelial, smooth muscle cells and fibroblasts in the skin microvessels. These changes included the decrease in the number of mitochondria and their alterations (vacuolization, destruction of the cristae, the presence of the needle-shaped crystals and crystal-like inclusions) and swelling of the endoplasmic reticulum. Some of these changes were characteristic of mitochondrial diseases. The changes in the extracellular matrix (thickening of the subendothelial layer and...