Background/Objectives: Normal-appearing white (WM) and gray (GM) matter outside focal demyelinating lesions (WMH) has been found impaired in many diseases and normal aging. The present study aimed to compare global GM and WM alterations in patients with multiple sclerosis (MS), Parkinson's disease, long COVID (LC) and normal aging. Methods: The study population comprised 196 participants including patients with MS (n = 42), PD (n = 16), LC (n = 75), and healthy volunteers (n = 63). All participants underwent MR scanning using the fast macromolecular fraction (MPF) mapping protocol and routine clinical sequences. MPF in global normal-appearing WM, GM, and mixed WM-GM was measured after exclusion of segmented focal lesions. To eliminate the influence of gender, age, and brain atrophy on the results, the corresponding covariates were included in the analysis. Results: Significant WMH volume increase and MPF decrease in global WM, WM-GM, and GM were found both in normal aging (75-85 years) and MS, PD, and LC patients (except for WM and WMH volume in LC patients). The greatest MPF decrease was observed in MS patients. The youngest (18-24 years) controls had a significant MPF decrease in global WM, WM-GM, and GM compared to middle-aged (35-44 years) participants. Among LC patients, the greatest global MPF reduction was found in patients with depression and insomnia as COVID-19 complications. In healthy controls, the peak age of myelination was estimated as 42.2 years for WM, 46.5 years for WM-GM, and 45.4 years for GM. Significant correlations were found between MPF and EDSS in MS patients (r = -0.71 in GM, r = -0.58 in WM-GM, r = -0.44 in WM) and stage of PD in PD patients (r = -0.58 in GM, r = -0.55 in WM-GM, r = -0.52 in WM). Conclusions: MPF mapping showed high sensitivity to age-related and disease-related differences in brain myelination, particularly in GM. Our results confirm the feasibility of using MPF mapping in large-scale clinical studies.

Insomnia and depression are severe sequelae of COVID-19 and often occur simultaneously. Our study examined associations of insomnia and/or depression with cognitive impairments, white matter changes, and serum biomarkers. In total, 76 long COVID patients and 22 healthy controls were examined using neuropsychiatric (ISI, HADS, and HDRS) and cognitive (MoCA, Stroop, WMT, and TMT) tests, with their blood biomarkers (anti-SARS-CoV-2, BDNF, anti-S100, anti-MBP, and anti-PLP) investigated, and underwent MRI using macromolecular proton fraction (MPF) mapping to quantify myelination. The Insomnia (n = 14), Depression (n = 12), InsDep (comorbid insomnia-depression, n = 13), and PostCovid (long COVID without depression and insomnia, n = 32) groups were identified based on psychiatric/neurological diagnoses and neuropsychiatric assessment. Cognitive performance was most affected in the Insomnia group in the MoCA and CW Stroop tests. The Depression group underperformed in the TMT and W Stroop task; the InsDep group underperformed in the WMT. The Insomnia group showed the greatest demyelination, affecting commissural (CC and tapetum), projection (CR, IC, CST, cerebral peduncles, CP, and ML), and some association pathways (SLF, SFOF), as well as most juxtacortical regions, the thalamus, and the midbrain; these changes correlated with insomnia severity. The Depression and InsDep groups showed smaller but significant overall demyelination correlated with depression severity. The Depression group exhibited the highest MPF decrease in the globus pallidus, putamen, and external capsule, while the InsDep group demonstrated the highest demyelination of the association pathways IFOF, UF, and cingulum. The anti-PLP levels were the highest in the Insomnia group and correlated with both the persistence of insomnia/depression symptoms and demyelination. Demyelination in long COVID is associated with high levels of myelin-specific autoantibodies, but symptoms of insomnia and/or depression are associated with demyelination of a different set of brain structures.

Background: Depression and cognitive impairment are recognized complications of COVID-19. This study aimed to assess cognitive performance in clinically diagnosed post-COVID depression (PCD, n = 25) patients using neuropsychological testing. Methods: The study involved 71 post-COVID patients with matched control groups: recovered COVID-19 individuals without complications (n = 18) and individuals without prior COVID-19 history (n = 19). A post-COVID depression group (PCD, n = 25) was identified based on psychiatric diagnosis, and a comparison group (noPCD, n = 46) included participants with neurological COVID-19 complications, excluding clinical depression. Results: The PCD patients showed gender-dependent significant cognitive impairment in the MoCA, Word Memory Test (WMT), Stroop task (SCWT), and Trail Making Test (TMT) compared to the controls and noPCD patients. Men with PCD showed worse performances on the SCWT, in MoCA attention score, and on the WMT (immediate and delayed word recall), while women with PCD showed a decline in MoCA total score, an increased processing time with less errors on the TMT, and worse immediate recall. No differences between groups in Sniffin’s stick test were found. Conclusions: COVID-related direct (post-COVID symptoms) and depression-mediated (depression itself, male sex, and severity of COVID-19) predictors of decline in memory and information processing speed were identified. Our findings may help to personalize the treatment of depression, taking a patient’s gender and severity of previous COVID-19 disease into account.

Introduction. Studying the influence of multilingualism on the human psyche is an urgent problem in physiology. It is believed that “communicative” mirror neurons played an important role in the emergence of speech and language in humans. However, it is still unclear what changes occur in the speech structures of the brain and, in particular, in the mirror neuron system during the acquisition of a second language. The purpose of this study was to study the activity of mirror neurons in monolinguals and bilinguals when observing and pronouncing emotional and non-emotional words in their native (Russian) and non-native (English) languages. Methods. The study involved boys and girls: monolinguals with English proficiency level A1 (elementary) or A2 (pre-intermediate) on the CEFR (Common European Framework of Reference) scale and bilinguals with English proficiency level B2 (upper intermediate) or C1 (advanced) ). Type of bilingualism: sequential and artificial. Participants in the experiment either silently uttered emotional (“PAIN”) and non-emotional words (ONE) in their native (Russian) and non-native (English) languages with their lips alone, or watched an operator who pronounced those the same words. The words were pronounced by the operator or the subject at the moments when the stopwatch hand on the monitor screen passed through the divisions of 0, 5, 10, etc. seconds. At the same time, the stopwatch hand made 5 revolutions. Before performing the activity and during its implementation, the participants’ EEG was recorded monopolarly using a 24-channel encephalograph-analyzer “Encephalan-131-03” in the frontal (F3, F4, Fz, F7, F8), central (C3, C4, Cz), temporal (T3, T4, T5, T6), parietal (P3, P4, Pz) and occipital (O1, O2) leads according to the “10–20 %” system. Leads A1 and A2 were used as referents. When processing the data obtained, estimates of spectral power were calculated in short segments of the EEG recording (1.5 s), devoid of artifacts: 1.5 s (preparation stage) before the stopwatch hand crosses the corresponding division, immediately after the specified event (action execution stage) and after 1.5 s after the arrow crosses the division (background stage). The obtained spectral power values were averaged separately for each stage of activity, for each series and for all subjects. For statistical data processing, the MatLab v6.5 package and the Wilcoxon test for related samples were used. Results. When preparing and performing speech actions in their native and non-native languages, monolinguals and bilinguals showed multidirectional changes in the spectral power of the mu rhythm at different frequencies. It has been shown that in monolinguals and bilinguals, when observing and pronouncing words, depression of the mu rhythm is observed not only during the performance of a speech act, but also at the stage of its preparation. In bilinguals (men and women), a more pronounced decrease in the spectral power of the mu rhythm was found compared to monolinguals (men and women) when observing and pronouncing emotional and unemotional words in their native and non-native languages, which indicates a more significant activation of “communicative” mirror neurons in bilinguals. This is manifested in the fact that a decrease in the spectral power of this rhythm is observed in bilinguals at different frequencies and in different EEG leads, while in monolinguals the decrease in the spectral power of the mu rhythm is either insignificant or absent. Conclusion. It is assumed that the more pronounced activation of “communicative” mirror neurons in bilinguals when observing and pronouncing words in their native (Russian) and non-native (English) languages is due to the fact that the acquisition of a non-native language is accompanied by an increase in the number of “communicative” mirror neurons in bilinguals in the corresponding zones of the cortex due to neurogenesis.

Background: The fundamental question of normal brain myelination in human is still poorly understood. Methods: Age-dependent global, regional, and interhemispheric sex-related differences in brain myelination of 42 (19 men, 23 women) healthy adults (19-67 years) were explored using the MRI method of fast macromolecular fraction (MPF) mapping. Results: Higher brain myelination in males compared to females was found in global white matter (WM), most WM tracts, juxtacortical WM regions, and putamen. The largest differences between men and women, exceeding 4%, were observed bilaterally in the frontal juxtacortical WM; angular, inferior occipital, and cuneus WM; external capsule; and inferior and superior fronto-orbital fasciculi. The majority of hemispheric differences in MPF were common to men and women. Sex-specific interhemispheric differences were found in juxtacortical WM; men more often had left-sided asymmetry, while women had right-sided asymmetry. Most regions of deep gray matter (GM), juxtacortical WM, and WM tracts (except for projection pathways) showed a later peak age of myelination in women compared to men, with a difference of 3.5 years on average. Body mass index (BMI) was associated with higher MPF and later peak age of myelination independent of age and sex. Conclusions: MPF mapping showed high sensitivity to assess sex-related differences in normal brain myelination, providing the basis for using this method in clinics.

An assessment was made of hematological parameters of peripheral blood and structural and functional changes in the adrenal glands in stress-unresistant rats (passive-defensive type of behavior in the open field test) after exposure to light deprivation and physical activity during the spring equinox. The experiment showed that light deprivation for 10 days reduces the total number of leukocytes, the absolute content of monocytes, granulocytes, lymphocytes and the level of corticosterone in the peripheral blood compared to the intact group, that was on a natural lighting regime. Histological analysis of the adrenal glands of this group showed, that in the zona fasciculata under such conditions there was nuclear hypertrophy, an increase in the nuclear-cytoplasmic ratio of adrenocorticocytes and a decrease in the size of the zona glomerulosa of the adrenal cortex of rats in relation to the intact group. Physical activity in the form of forced swimming until complete fatigue for 5 days in a row in natural light in stress-unresistant rats did not change the parameters of the peripheral blood of animals, however it led to an increase in the area of the cytoplasm, the nuclear-cytoplasmic ratio, as well as the formation of nuclear hypertrophy of adrenocorticocytes in the fascicle adrenal zones, which indicated the preparation of cells for increased synthetic activity. Keeping rats for 10 days in complete darkness before forced swimming every day for 5 days, on the one hand, formed a hypoxic state and exhaustion of the adrenal glands, on the other hand, stabilized the leukocyte pool of peripheral blood compared to similar indicators in intact rats.

Background: Depression is one of the most severe sequelae of COVID-19, with major depressive disorder often characterized by disruption in white matter (WM) connectivity stemming from changes in brain myelination. This study aimed to quantitatively assess brain myelination in clinically diagnosed post-COVID depression (PCD) using the recently proposed MRI method, macromolecular proton fraction (MPF) mapping. Methods: The study involved 63 recovered COVID-19 patients (52 mild, 11 moderate, and 2 severe) at 13.5 ± 10.0 months post-recovery, with matched controls without prior COVID-19 history (n = 19). A post-COVID depression group (PCD, n = 25) was identified based on psychiatric diagnosis, while a comparison group (noPCD, n = 38) included participants with neurological COVID-19 complications, excluding clinical depression. Results: Fast MPF mapping revealed extensive demyelination in PCD patients, particularly in juxtacortical WM (predominantly occipital lobe and medial surface), WM tracts (inferior fronto-occipital fasciculus (IFOF), posterior thalamic radiation, external capsule, sagittal stratum, tapetum), and grey matter (GM) structures (hippocampus, putamen, globus pallidus, and amygdala). The noPCD group also displayed notable demyelination, but with less magnitude and propagation. Multiple regression analysis highlighted IFOF demyelination as the primary predictor of Hamilton scores, PCD presence, and severity. The number of post-COVID symptoms was a significant predictor of PCD presence, while the number of acute symptoms was a significant predictor of PCD severity. Conclusions: This study, for the first time, reveals extensive demyelination in numerous WM and GM structures in PCD, outlining IFOF demyelination as a key biomarker.

An electrophysical model of the otolith organs of the vestibular apparatus of a laboratory animal (rat) has been developed using an equivalent electrical circuit. The electrophysical model is presented as a set of conducting and dielectric regions based on the anatomical structure determined from MRI/CT images. The equivalent electrical circuit for the replacement of the otolith organs of the vestibular apparatus of the laboratory animal is based on the measured specific electrical characteristics of the tissues of the otolith structures taking into account the changing ionic conductivity of the hair cells. To determine the spectral sensitivity of otolith organs, the electrical impedance of the cellular elements of the utricle and saccule and the phase shift of the flowing current with respect to an external electrical stimulus were calculated based on the geometric data and electrophysical parameters of the otolith organs of the laboratory animal (rat) in the frequency range 0-5000 Hz. It has been shown that the response of hair cells of the otolith membranes to an external electrical stimulus is oscillatory.

Age-related myelination decrease is considered one of the likely mechanisms of cognitive decline. The present preliminary study is based on the longitudinal assessment of global and regional myelination of the normal adult human brain using fast macromolecular fraction (MPF) mapping. Additional markers were age-related changes in white matter (WM) hyperintensities on FLAIR-MRI and the levels of anti-myelin autoantibodies in serum. Eleven healthy subjects (33–60 years in the first study) were scanned twice, seven years apart. An age-related decrease in MPF was found in global WM, grey matter (GM), and mixed WM–GM, as well as in 48 out of 82 examined WM and GM regions. The greatest decrease in MPF was observed for the frontal WM (2–5%), genu of the corpus callosum (CC) (4.0%), and caudate nucleus (5.9%). The age-related decrease in MPF significantly correlated with an increase in the level of antibodies against myelin basic protein (MBP) in serum (r = 0.69 and r = 0.63 for global WM and mixed WM–GM, correspondingly). The volume of FLAIR hyperintensities increased with age but did not correlate with MPF changes and the levels of anti-myelin antibodies. MPF mapping showed high sensitivity to age-related changes in brain myelination, providing the feasibility of this method in clinics.

Bilateral asymmetry in the function of the semicircular canals underlies dizziness and vestibular balance disorders. According to the traditional view, otolith dysfunction does not have a significant effect on the clinical picture in individuals with peripheral vestibular disorders. In recent years, interest in studying the contribution of vestibular function to the control of posture and movements has increased. However, we have not identified any studies addressing the reactivity of otolith organs in vestibular balance disorders in the available literature.Aim: To study bilateral otolith reactions in patients with vestibular balance disorders using the method of cervical vestibular evoked myogenic potentials (cVEMP) in patients with episodic and chronic vestibular disorders.Material and Methods. A clinical examination was carried out in 63 patients complaining of dizziness and balance problems. They were hospitalized on an emergency and planned basis in the neurological departments of the clinics of the Siberian State Medical University and the Medical and Sanitary Unit No 2 in Tomsk. From the total group, 28 patients (8 men and 20 women aged from 22 to 84 years) were selected for assessment of vestibular function; the average age was 63.87 ± 11.52 years and 57.2 ± 18.5 years for men and women respectively. They had chronic and episodic vestibular dysfunction unrelated to acute or progressive neurological disease and inflammatory pathology of the inner ear.Results. 27 patients (96.4%) complained of dizziness. Systemic dizziness, characterized by a feeling of objects rotating around the subject, was detected in 29.63% of patients; non-systemic dizziness, including a feeling of “failing” – in 81.48%. Both types of complaints appeared in 10.71% of those examined, which made it possible to identify 2 groups of patients: Group A – with chronic vestibular disorders (7 patients) and Group B – with episodic vestibular disorders (21 patients). During the study of the groups of patients, differences were found in the amplitudes of cVEMP latency P13 and the coefficient of vestibular asymmetry between Groups A and B, as well as the absence of a difference in amplitudes in Group A and the presence of a difference in Group B on the right.Conclusion. Despite the fact that patients presented with predominantly one complaint of dizziness, clinical and instrumental tests of vestibular dysfunction showed the presence of damage to both the semicircular canals and otolithic organs; asymmetry of vestibular reflexes and/or bilateral damage to the vestibular organs. The results of the study allow us to consider the cVEMP method as one of the methods for objectively assessing the condition of the otolithic apparatus in patients with impaired vestibular function. In this regard, it is recommended to use this method in routine neurological practice.

Age-related myelination decrease is considered one of the likely mechanisms of cognitive decline. The present study is based on the longitudinal assessment of global and regional myelination of the normal adult human brain using the fast macromolecular fraction (MPF) mapping. Additional markers were age-related changes in white matter (WM) hyperintensities on FLAIR-MRI and the levels of anti-myelin autoantibodies in serum. Eleven healthy subjects (33–60 years in the first study) were scanned twice, 7 years apart. An age-related decrease in MPF was found in global WM, GM, and mixed WM-GM, as well as in 48 out of 82 examined WM and GM regions. The greatest decrease in MPF was observed for the frontal WM (2-5%), genu of the corpus callosum (CC) (4.0%) and caudate nucleus (5.9%). The age-related decrease in MPF significantly correlated with an increase in the level of antibodies against myelin basic protein (MBP) in serum (r = 0.69 and r = 0.63 for global WM and mixed WM-GM, correspondingly). The volume of FLAIR hyperintensities increased with age but did not correlate with MPF changes and the levels of anti-myelin antibodies. MPF mapping showed high sensitivity to age-related changes in brain myelination, providing the feasibility of this method in clinics.

The effect of humic acids and substances with similar action - derivatives of succinic acid (ethylmethylhydroxypyridine succinate) and combined agent consisting of succinic acid, nicotinamide, riboflavin, and riboxin on the performance and stress resistance of experimental rats was studied. Performance was assessed in the test of exhaustive forced swimming with a load, stress resistance was evaluated by the serum level of corticosterone and open field behavior, and the state of anaerobic metabolism was estimated by the serum level of lactate after swimming test. Humic acids from peat showed anti-stress activity comparable to that of the officinal preparation and preventive effect on fatigue during physical exercise. They can be recommended as a component for the development of drugs that increase human performance and stress resistance.

The effect of nanosecond repetitive pulsed microwave radiation (RPMR) (50–4000 pulses, pulse repetition rate of 13 Hz, peak power flux density (pPFD) of 140 W/cm2, and carrier frequency of 10 GHz) on the stimulation of proliferation of mesenchymal stem cells (MSCs) is investigated. The effect of exposure was assessed by the change in the number of cells in the culture after a single irradiation with different numbers of pulses. The effect was the most pronounced after exposure with 100 and 50 pulses; the maximum rate of the effect realization is in 24 h.

Traditionally histology is the gold standard for the validation of imaging experiments. Matching imaging slices and histological sections and the precise outlining of corresponding tissue structures are difficult. Challenges are based on differences in imaging and histological slice thickness as well as tissue shrinkage and alterations after processing. Here we describe step-by-step instructions that might be used as a universal pathway to overlay MRI and histological images and for a correlation of measurements between imaging modalities. The free available (Fiji is just) ImageJ software tools were used for regions of interest transformation (ROIT) and alignment using a rat brain MRI as an example. The developed ROIT procedure was compared to a manual delineation of rat brain structures. The ROIT plugin was developed for ImageJ to enable an automatization of the image processing and structural analysis of the rodent brain.

The aim of the research was to study the men and women brain activity in during memorizing and reproducing rhythm (5 s) and measuring short time intervals (0.8 s) by fMRI method. Volunteers are young people (boys and girls) aged 18 to 27 years. It was shown that extensive brain areas (prefrontal and motor cortex, insular cortex, sensory and associative areas of the parietal and temporal cortex, amygdala, hippocampus, thalamus, basal ganglia and cerebellum) are involved in providing sensorimotor activity associated with rhythm reproduction and measuring short time intervals. It was found that the measurement of short time intervals is partially provided by the same brain structures as the rhythm reproduction. When measuring the duration, the activation in both hemisphere of a number of additional structures (frontal pole, supraorbital gyrus, angular gyrus, temporal area and some other cortical areas) was detected. The results of this study indicate that the “brain support” of sensorimotor activity associated with rhythm reproduction and measuring short time intervals significantly depends on the method of scaling time intervals and gender differences.

С помощью функциональной магнитно-резонансной томографии (фМРТ) исследовали особенности активации мозговых структур при произнесении эмоционального и неэмоционального слов вслух и про себя. В исследованиях участвовали добровольцы - 20 мужчин и 20 женщин в возрасте от 19 до 27 лет, учащиеся вузов. В ходе предварительного обследования с помощью анкеты Аннет выявляли ведущую руку. Исследование включало несколько серий экспериментов. В первой серии ("Произнесение неэмоционального слова вслух") испытуемый произносит слово "Раз" вслух в моменты перехода стрелки секундомера на экране монитора через деления 0, 5, 10 и т.д. секунд. Во второй серии ("Произнесение неэмоционального слова про себя") испытуемый произносит слово "Раз" про себя в те же моменты времени. В третьей серии ("Произнесение эмоционального слова вслух") испытуемый произносит слово "Боль" в указанные моменты времени (0, 5, 10 и т.д. секунд). В четвертой серии ("Произнесение эмоционального слова про себя") испытуемый произносит слово "Боль" про себя в указанные моменты времени. В качестве контроля испытуемому демонстрировали видеоролик с изображением движущейся стрелки секундомера ("Состояние покоя"). Согласно инструкции, испытуемый в этом случае должен был только следить за стрелкой секундомера. Результаты структурной и функциональной МРТ получены в НБИКС-технологий НИЦ "Курчатовский институт" на томографе SIEMENS Magnetom Verio 3 Tesla. Все фМРТданные были предварительно обработаны с помощью пакета SPM8. В рамках каждой из парадигм были выполнены попарные сравнения на основании статистики Стьюдента и получены индивидуальные и групповые карты с уровнем значимости p < 0,001. Все полученные статистические карты наносились на шаблонное Т-1 изображение и производилась анатомическая привязка "активных" вокселов к атласу CONN. Показано, что произнесение эмоционального и неэмоционального слов про себя сопровождается активацией лишь части мозговых структур, которые активируются при произнесении тех же слов вслух. К тому же эти структуры активируются значительно слабее. Установлено, что произнесение неэмоционального слова сопровождается у женщин активацией дополнительной моторной коры, справа и слева, верхней лобной извилины, слева, прецентральной извилины, справа и слева, верхней и средней височных извилин, слева, а также таламуса, слева и некоторых других зон коры. Оказалось, что произнесение про себя эмоционального слова сопровождается у мужчин активацией прецентральной извилины, справа и слева, нижней лобной извилины, слева, средней височной извилины, справа, а также гиппокампа и миндалины. Предполагается, что перечисленные структуры участвуют в обеспечении внутренней речи и мышления. Functional magnetic resonance imaging (fMRI) was used to study the activation of brain structures during the pronunciation of emotional and non-emotional words aloud and to oneself. Volunteers - 20 men and 20 women aged 19 to 27 years old, university students participated in the research. During the preliminary examination, the dominant hand was identified using the Annette questionnaire. The study included several series of experiments. In the first series ("Saying an unemotional word aloud"), the subject pronounces the word “One” aloud at the moments when the stopwatch arrow on the monitor screen passes through divisions 0, 5, 10, etc. seconds. In the second series ("Pronouncing an unemotional word to oneself"), the subject pronounces the word "One" to himself at the same time. In the third series ("Saying the emotional word aloud"), the subject pronounces the word "Pain" at the specified time points (0, 5, 10, etc. seconds). In the fourth series ("Pronouncing an emotional word to himself"), the subject pronounces the word "Pain" to himself at the indicated time points. As a control, the subject was shown a video clip depicting a moving stopwatch hand ("Resting State"). According to the instructions, the subject in this case had only to follow the stopwatch hand. The results of structural and functional MRI were obtained at the NBICS-technologies of the National Research Center "Kurchatov Institute" on a SIEMENS Magnetom Verio 3 Tesla tomograph. All fMRI data were preprocessed using the SPM8 package. Within each of the paradigms, pairwise comparisons were performed based on Student's statistics and individual and group maps were obtained with a significance level of p < 0.001. All obtained statistical maps were plotted on a template T-1 image and anatomical binding of "active" voxels to the CONN atlas was made. It is shown that the pronunciation of emotional and non-emotional words to oneself is accompanied by the activation of only a part of the brain structures that are activated when the same words are pronounced aloud. In addition, these structures are activated much weaker. It has been established that the pronunciation of an unemotional word in women is accompanied by activation of the additional motor cortex, on the right and left, the superior frontal gyrus, on the left, the precentral gyrus, on the right and left, the superior and middle temporal gyri, on the left, as well as the thalamus, on the left and some other cortical zones. It turned out that pronouncing an emotional word to oneself is accompanied in men by activation of the precentral gyrus, on the right and left, the inferior frontal gyrus, on the left, the middle temporal gyrus, on the right, as well as the hippocampus and amygdala. It is assumed that the listed structures are involved in the provision of inner speech and thinking.