Major depressive disorder (MDD) is associated with complex disruptions in brain function, yet the underlying neural mechanisms remain incompletely understood. Traditional approaches to studying functional brain networks have primarily focused on pairwise interactions between brain regions, offering valuable insights into basic connectivity. However, such methods often fail to capture the complexity of higher-order interactions that are critical for understanding integrative processes in the brain. This study aims to address this gap by applying Q-analysis, a mathematical framework that extends beyond pairwise interactions, to fMRI-derived brain networks to investigate higher-order interactions and structural organization in individuals with MDD compared to healthy controls (HCs). Our analysis revealed significant alterations in the topology of brain networks in MDD patients, characterized by a lower maximum topology level and an increased prevalence of isolated edges and chains at the pairwise interaction level. The substantia nigra area demonstrated a higher topological dimension in MDD, suggesting its greater integration into disrupted network structures, potentially reflecting dopaminergic dysfunction associated with the disorder. Additionally, the consensus networks at higher topology levels indicated distinct network configurations between MDD patients and HCs, with the former exhibiting a single q-connected component primarily involving limbic, cerebellar, and occipital-temporal regions. We identified significant disruptions in the higher-order organizational structures of the brain, characterized by reduced topological diversity and complexity, fewer and less connected cliques, and altered involvement of key brain regions in MDD: the increased engagement of the limbic structures such as the substantia nigra, parahippocampal gyrus, and hippocampus, and decreased involvement of the cerebellum, the occipital and temporal lobes. Our study introduces a novel approach to understanding MDD pathophysiology through the lens of higher-order network structures, offering potential avenues for more targeted diagnostic and therapeutic strategies.

Objective: Spinal cord stimulation (SCS) is one approach to the potential improvement of patients with post-stroke or post-traumatic spasticity. However, little is known about whether and how such interventions alter supraspinal neural systems involved in the pathogenesis of spasticity. This pilot study investigated whether epidural spinal cord stimulation at the level of the C3–C5 cervical segments, aimed at reducing spasticity, alters the patterns of functional connectivity of the brain. Methods: Eight patients with spasticity in the right limbs as a result of left cerebral hemisphere damage (due to hemorrhagic and ischemic stroke or traumatic and anoxic brain injury) were assessed with fMRI immediately before and immediately after short-term (1 to 6 days) test cervical epidural SCS therapy. Eight demographically and clinically comparable patients with spasticity in the right extremities due to a left hemisphere ischemic stroke and brain injury who received conventional therapy were examined as a control group. All patients also had paresis of one or two limbs and hyperreflexia. Results: After the SCS therapy, there were three main findings: (1) higher functional connectivity of the brainstem to the right premotor cortex and changes in functional connectivity between cortical motor areas, (2) increased functional connectivity between the right and left lateral nodes of the sensorimotor network, and (3) a positive correlation between decreased spasticity in the right leg and increased functional connectivity within the right hemisphere sensorimotor cortex. All these changes in functional connectivity occurred with a statistically significant decrease in spasticity, as assessed using the modified Ashworth scale. The control group showed no decrease in spasticity or increase in functional connectivity in any of the seeds of interest. On the contrary, a decrease in functional connectivity of the brainstem and right postcentral gyrus was observed in this group during the observation period. Conclusions: We were thus able to detect intrinsic brain connectivity rearrangements that occurred during spasticity mitigation following short epidural SCS therapy. Significance: The clinical results obtained confirmed the efficacy of short-term anti-spastic SCS therapy. The obtained data on functional rearrangements of the central motor system may shed light on the mechanism of antispastic action of this procedure.

Background: The perception of basic emotional sounds, such as crying and laughter is associated with effective interpersonal communication. Difficulties with the perception and analysis of sounds that complicate understanding emotions at an early development age may contribute to communication deficits. Methods: This study focused on auditory nonverbal emotional perception including emotional vocalizations with opposite valences (crying and laughter) and neutral sound (phoneme “Pᴂ”). We conducted event-related potential analysis and compared peak alpha frequencies (PAFs) for different conditions in children with autism spectrum disorder (ASD) and typically developing (TD) children aged 4 to 6 years old (N = 25 for each group). Results: Children with ASD had a higher amplitude of P100 and lower amplitude of N200 for all types of sounds and higher P270 in response to neutral phoneme. During the perception of emotional sounds, children with ASD demonstrated a single P270 electroencephalography (EEG) component instead of a P200–P300 complex specific to TD children. However, the most significant differences were associated with a response to emotional valences of stimuli. The EEG differences between crying and laughter were expressed as a lower amplitude of N400 and higher PAF for crying compared to laughter and were found only in TD children. Conclusions: Children with ASD have shown not just abnormal acoustical perception but altered emotional analysis of affective sounds as well.

ЦЕЛЬ ИССЛЕДОВАНИЯ Изучить влияние 10-дневного когнитивного тренинга с применением технологии интерфейс «мозг—компьютер» (ИМК) на волне P300 на восстановление когнитивных функций у пациентов, перенесших инсульт. МАТЕРИАЛ И МЕТОДЫ В исследование включены 30 пациентов в возрасте 22—82 лет с ишемическим инсультом давностью до 3 мес и наличием умеренных когнитивных нарушений (<26 баллов по Монреальской шкале оценки когнитивных функций, MoCA). Всем пациентам проводились нейропсихологическое тестирование, оценка наличия депрессии, оценка активности в повседневной жизнедеятельности. Пациенты рандомизированы в две группы: пациенты 1-й группы проходили 10-дневный курс когнитивной реабилитации в виде ежедневного выполнения упражнений в среде ИМК на волне P300, снабженной гарнитурой для регистрации электроэнцефалограммы (ЭЭГ). Пациенты 2-й группы получали стандартный комплекс реабилитационных мероприятий. РЕЗУЛЬТАТЫ Отмечалось увеличение среднего балла домена «Внимание» шкалы MoCA в основной группе пациентов по сравнению с контролем: с 2,3±1,24 до 5,2±1,16 балла против с 5,9±1,00 до 4,2±0,94 балла соответственно (p<0,05). Результаты ковариационного анализа с повторными измерениями с учетом факторов «Визит» и «Группа», ковариат «Депрессия» и «Количество тренировок» выявили статистически значимые эффекты для доменов «Называние» (p<0,05), «Внимание» (p<0,05), «Абстракция» (p<0,05) шкалы MoCA. К окончанию 10-дневного когнитивного тренинга с использованием ИМК у пациентов 1-й группы наблюдалось статистически значимое увеличение количества вводимых букв — с 20,8±2,01 до 25,9±1,7 символов (p=0,02), во 2-й группе — с 21,9±1,9 до 23,1±1,8 (p=0,06). При сравнении количества слов, вводимых пациентами через 10 дней, выявлена статистически значимая разница между группами (p<0,05). ЗАКЛЮЧЕНИЕ Реабилитация пациентов с постинсультными когнитивными нарушениями с использованием ИМК на волне P300 оказывает значимый положительный эффект на восстановление когнитивных функций, в первую очередь внимания.