Continuous three-dimensional control of a virtual helicopter using a motor imagery based brain-computer interface

Brain-computer interfaces (BCIs) allow a user to interact with a computer system using thought. However, only recently have devices capable of providing sophisticated multi-dimensional control been achieved non-invasively. A major goal for non-invasive BCI systems has been to provide continuous, intuitive, and accurate control, while retaining a high level of user autonomy. By employing electroencephalography (EEG) to record and decode sensorimotor rhythms (SMRs) induced from motor imaginations, a consistent, user-specific control signal may be characterized. Utilizing a novel method of interactive and continuous control, we trained three normal subjects to modulate their SMRs to achieve three-dimensional movement of a virtual helicopter that is fast, accurate, and continuous. In this system, the virtual helicopter's forward-backward translation and elevation controls were actuated through the modulation of sensorimotor rhythms that were converted to forces applied to the virtual helicopter at every simulation time step, and the helicopter's angle of left or right rotation was linearly mapped, with higher resolution, from sensorimotor rhythms associated with other motor imaginations. These different resolutions of control allow for interplay between general intent actuation and fine control as is seen in the gross and fine movements of the arm and hand. Subjects controlled the helicopter with the goal of flying through rings (targets) randomly positioned and oriented in a three-dimensional space. The subjects flew through rings continuously, acquiring as many as 11 consecutive rings within a five-minute period. In total, the study group successfully acquired over 85% of presented targets. These results affirm the effective, three-dimensional control of our motor imagery based BCI system, and suggest its potential applications in biological navigation, neuroprosthetics, and other applications.     

Contribution of psychoacoustics and neuroaudiology in revealing correlation of mental disorders with central auditory processing disorders

BACKGROUND: Psychoacoustics is a fascinating developing field concerned with the evaluation of the hearing sensation as an outcome of a sound or speech stimulus. Neuroaudiology with electrophysiologic testing, records the electrical activity of the auditory pathways, extending from the 8th cranial nerve up to the cortical auditory centers as a result of external auditory stimuli. Central Auditory Processing Disorders may co-exist with mental disorders and complicate diagnosis and outcome. DESIGN: A MEDLINE search was conducted to search for papers concerning the association between Central Auditory Processing Disorders and mental disorders. The research focused on the diagnostic methods providing the inter-connection of various mental disorders and central auditory deficits. MEASUREMENTS AND MAIN RESULTS: The medline research revealed 564 papers when using the keywords 'auditory deficits' and 'mental disorders'. 79 papers were referring specifically to Central Auditory Processing Disorders in connection with mental disorders. 175 papers were related to Schizophrenia, 126 to learning disabilities, 29 to Parkinson's disease, 88 to dyslexia and 39 to Alzheimer's disease. Assessment of the Central Auditory System is carried out through a great variety of tests that fall into two main categories: psychoacoustic and electrophysiologic testing. Different specialties are involved in the diagnosis and management of Central Auditory Processing Disorders as well as the mental disorders that may co-exist with them. As a result it is essential that they are all aware of the possibilities in diagnostic procedures. CONCLUSIONS: Considerable evidence exists that mental disorders may correlate with CAPD and this correlation could be revealed through psychoacoustics and neuroaudiology. Mental disorders that relate to Central Auditory Processing Disorders are: Schizophrenia, attention deficit disorders, Alzheimer's disease, learning disabilities, dyslexia, depression, auditory hallucinations, Parkinson's disease, alcoholism, anorexia and childhood mental retardation. Clinical awareness should be high in order for doctors of the two specialties, psychiatry and otorhinolaryngology-audiology to collaborate.     

In vitro ligament-bone interface regeneration using a trilineage coculture system on a hybrid silk scaffold

The ligament-bone interface is a complex structure that comprises ligament, fibrocartilage, and bone. We hypothesize that mesenchymal stem cells cocultured in between ligament and bone cells, on a hybrid silk scaffold with sections suitable for each cell type, would differentiate into fibrocartilage. The section of scaffold for osteoblast seeding was coated with hydroxyapatite. A trilineage coculture system (osteoblasts-BMSCs-fibroblasts) on a hybrid silk scaffold was established. RT-PCR results and immunohistochemistry results demonstrated that BMSCs cocultured between fibroblasts and osteoblasts had differentiated into the fibrocartilaginous lineage. The morphological change was also observed by SEM observation. A gradual transition from the uncalcified to the calcified region was formed in the cocultured BMSCs from the region that directly interacted with fibroblasts to the region that directly interacted with osteoblasts. The role of transforming growth factor β3 (TGF-β3) in this trilineage coculture model was also investigated by supplementing the coculture system with 10 ng/mL TGF-β3. The TGF-treated group showed similar results of fibrocartilaginous differentiation of BMSCs with coculture group without TGF-β3 supplement. However, no calcium deposition was found in the cocultured BMSCs in the TGF-treated group. This may indicate TGF-β3 delayed the mineralization process of chondrocytes.     

脑机接口中脑电信号提取方法和技术的研究进展

脑机接口(BCI)系统可以把大脑发出的信息直接转换成能够驱动外部设备的命令,并代替人的肢体或感觉器官实现人与外界的交流以及对外部环境的控制。BCI技术的发展目前还存在着很多问题,其中最关键的问题是必须有一个安全的、可长时间持续探测或者注射信号的方法。该文综述了当前BCI研究中不同脑电信号的提取方式特征以及信号记录装置,通过分析总结了其优缺点。对于各种不同信号方式的BCI,都有待于更多的科技工作者深入研究。     

The P300 based brain-computer interface: effect of stimulus position in a stimulus train

The P300 brain-computer interface (BCI) is currently the most efficient BCI. This interface is based on detection of the P300 wave of the brain potentials evoked when a symbol related to the intended input is highlighted. To increase operation speed of the P300 BCI, reduction of the number of stimuli repetitions is needed. This reduction leads to increase of the relative contribution to the input symbol detection from the reaction to the first target stimulus. It is known that the event-related potentials (ERP) to the first stimulus presentations can be different from the ERP to stimuli presented latter. In particular, the amplitude of responses to the first stimulus presentations is often increased, which is beneficial for their recognition by the BCI. However, this effect was not studied within the BCI framework. The current study examined the ERP obtained from healthy participants (n = 14) in the standard P300 BCI paradigm using 10 trials, as well as in the modified P300 BCI with stimuli presented on moving objects in triple-trial (n = 6) and single-trial (n = 6) stimulation modes. Increased ERP amplitude was observed in response to the first target stimuli in both conditions, as well as in the single-trial mode comparing to triple-trial. We discuss the prospects of using the specific features of the ERP to first stimuli and the single-trial ERP for optimizing the high-speed modes in the P300 BCIs.     

Detecting the number of clusters of individuals using the software STRUCTURE: a simulation study

The identification of genetically homogeneous groups of individuals is a long standing issue in population genetics. A recent Bayesian algorithm implemented in the software STRUCTURE allows the identification of such groups. However, the ability of this algorithm to detect the true number of clusters (K) in a sample of individuals when patterns of dispersal among populations are not homogeneous has not been tested. The goal of this study is to carry out such tests, using various dispersal scenarios from data generated with an individual-based model. We found that in most cases the estimated 'log probability of data' does not provide a correct estimation of the number of clusters, K. However, using an ad hoc statistic DeltaK based on the rate of change in the log probability of data between successive K values, we found that STRUCTURE accurately detects the uppermost hierarchical level of structure for the scenarios we tested. As might be expected, the results are sensitive to the type of genetic marker used (AFLP vs. microsatellite), the number of loci scored, the number of populations sampled, and the number of individuals typed in each sample.     

Systems analysis of the flow of associations in healthy subjects and patients with mental disorders

By means of mathematical apparatus of a model of frequency lexical structure the structure of repetitions was studied in association flows of 10 healthy persons, 10 patients with sequelae of closed craniocerebral injury, and 10 schizophrenics. In comparison to healthy persons in those after the brain injury the number of repetitions was increased and the distances between the first and the last use of the repeated words were significant. In schizophrenic persons the repetitions of the words were situated at the local portions of association flows. The structure of repetitions in these association flows was close to that of the usual connected text by the general quantitative norms. Such structure of repetitions should be explained by the presence of a parasitical system of connections between the words equivalent by its strength to usual rational connections in a meaningful text.     

The effectiveness of a group psycho-educational program on family caregiver burden of patients with mental disorders

ABSTRACT: BACKGROUND: Brief family intervention may have a positive impact on family caregivers to patients with mental disorders. We aimed to assess the effectiveness of a group psycho-educational program on family caregivers to patients with schizophrenia and mood disorders. METHOD: This randomized controlled trial was performed on 100 caregivers to patients with mental disorders attending Isfahan Behavioral Sciences Research Center, Isfahan, Iran. 100 family caregivers of patients with schizophrenia (n=50) and mood disorders (n=50) were selected and assigned randomly to either a psycho-educational group intervention or routine care in each diagnosis category. The caregivers were followed up for a period of 3 months. Caregiver burden was assessed using the Zarit Burden Interview. RESULTS: The burden decreased significantly in the group that participated in the psycho-educational program. The mean scores of the Zarit caregiver burden scale decreased, while scores in the control group did not change significantly. CONCLUSION: This group intervention program was effective for the Iranian studied population to reduce the caregiver burden in both categories of mental disorder. It may potentially improve the quality of life of both patients and caregivers by improving the standards of care giving.     

Patterns of urinary aminoacid excretion in exceptional children and patients with mental disorders in Costa Rica

The amino acid profile was studied in individual random samples of urine from 1147 normal schoolchildren and 1074 exceptional children: 628 with mental retardation, 332 with hearing and speech defects and 114 with visual defects as well as in 673 patients with mental disorders. Laboratory procedures included chemical tests and one-dimension paper- electro- and column-chromatography. Phenylketonuria was found in a mentally retarded girl and in one of her brothers; iminoglycinuria in a mentally retarded boy and heterozygote cystinuria in a man with manic-depressive psychosis. The percentage of high excretors of beta-aminoisobutyric acid (B-AIB) in the controls (4.88%) was similar to previous findings in the Caucasian race. The children with hearing and speech defects showed a number of high excretors of B-AIB significantly lower (X2 = 5.32; p less than 0.025) and the children with visual defects a number of hyperglycinurias significantly higher (X2 = 9.19; p less than 0.05). Previous non-consistent findings on the excess of high excretors of B-AIB in Down's syndrome were not confirmed in this study. These results suggest a relationship between transport defects in the plasma membrane and pathological disorders in some of the cases screened.     

Study of local EEG specificities in children with mental development disorders using independent component analysis

Baseline EEGs in the frequency range of 3–13 Hz in children with mental disorders of perinatal origin during wakefulness with the eyes open were analyzed using independent component analysis. In cases of severe mental retardation, a significant increase in the power density spectra of the θ band was revealed in the left-sided frontotemporal and right-sided temporal cortices, which allows us to consider these regions to be putative sources of slow activity and markers for a lesion or immaturity in the fronto-thalamic system, as well as for the temporal areas responsible for the auditory analysis and synthesis of speech signals and the integration of audio-visual information.     

A hybrid model for the neural representation of complex mental processing in the human brain

In the present conceptual review several theoretical and empirical sources of information were integrated, and a hybrid model of the neural representation of complex mental processing in the human brain was proposed. Based on empirical evidence for strategy-related and inter-individually different task-related brain activation networks, and further based on empirical evidence for a remarkable overlap of fronto-parietal activation networks across different complex mental processes, it was concluded by the author that there might be innate and modular organized neuro-developmental starting regions, for example, in intra-parietal, and both medial and middle frontal brain regions, from which the neural organization of different kinds of complex mental processes emerge differently during individually shaped learning histories. Thus, the here proposed model provides a hybrid of both massive modular and holistic concepts of idiosyncratic brain physiological elaboration of complex mental processing. It is further concluded that 3-D information, obtained by respective methodological approaches, are not appropriate to identify the non-linear spatio-temporal dynamics of complex mental process-related brain activity in a sufficient way. How different participating network parts communicate with each other seems to be an indispensable aspect, which has to be considered in particular to improve our understanding of the neural organization of complex cognition.     

Genome-wide mapping of copy number variations in commercial hybrid pigs using a high-density SNP genotyping array

Copy number variations (CNVs) are important forms of structural variation in human and animals and can be considered as a major genetic component of phenotypic diversity. Here we used the Illumina PorcineSNP60 BeadChip V2 and a DLY [Duroc × (Large White × Landrace)] commercial hybrid population to identify 272 CNVs belonging to 165 CNV regions (CNVRs), of which 66 are new. As CNVRs are specific to origin of population, our DLY-specific data is an important complementary to the existing CNV map in the pig genome. Eight CNVRs were selected for validation by quantitative real-time PCR (qRT-PCR) and the accurate rate was high (87.25%). Gene function analysis suggested that a common CNVR may play an important role in multiple traits, including growth rate and carcass quality.     

Characteristics of event-related potentials in response to symbolical and alphabetical stimulation matrices used in a P300-based brain-computer interface

In order to create a P300-based brain-computer interface (BCI) (the so-called Farwell-Donchin paradigm, FD) with a symbol matrix used as a stimulus, we compared characteristics of event-related potentials (ERPs) in response to stimulation by 6 × 6 matrices composed of either pictogram symbols or Cyrillic alphabet characters. Nine healthy adults were examined in 18 experiments, during which 28-channel EEGs were recorded in the course of stimulation with matrices of these two types. The obtained ERP data, i.e., amplitudes and peak latencies of the ERP components N1, P3 (with the P3a and P3b sub-components), and N4 were compared and analyzed for different types of stimulation matrices. In at least seven out of nine subjects, P3a, P3b, and N4 ERP amplitudes were larger in response to the symbol matrix than to the character matrix, while N1 amplitudes were larger for the character matrix. For N1 and P3a, the ERP latencies were shorter for the symbol matrix, while for P3b and N4, they were longer for the character matrix. The topography of differential ERP responses to the two types of stimuli was analyzed using a series of paired t-tests. Differences of ERP component amplitudes were determined individually for each of the 28 channels; next, for each site, absolute t-test values were summed for all nine subjects. For all ERP components studied, the t-test for peak amplitudes in response to target and non-target letters identified two separate areas with distinct lateralization. ERP responses to target and non-target symbols differed most in transversely extended areas. Finally, the yield surface of differential response to target letters and target symbols had a complex topography.     

Applications of a novel biodetection system to saliva using protein fingerprints with data processing

A fundamental method has been developed focusing on a facile and rapid examination of periodontal disease. Periodontal disease is an oral disease thought to affect 80% of adults, and early detection with treatment is desirable for the improvement of the quality of life. Unfortunately conventional methods are not consistent as the disease is caused by a number of undefined bacteria and detection relies on the skills of the dentist. Thus an objective detection system is required. We have performed an experiment on saliva using a novel biodetection system, designated PepTenChip®. A disease model for saliva was prepared using a specimen from a healthy subject and a mixture of hemoglobin (f-Hb) and lactate dehydrogenase (LDH), which is used as a periodontal disease marker protein with healthy saliva. PepTenChip® is a peptide microarray in which fluorescent labelled structured peptides are immobilized on a novel amorphous carbon substrate. Since the peptides used as capture molecules are fluorescently labelled, labeling of analytes is not necessary. The fluorescence intensity change before and after application of analytes are detected rather than the ON/OFF detection common to conventional microarrays using a set of antigen–antibody. The fluorescence intensity value changes according to the concentration of captured protein allowing the generation of protein fingerprint (PFP) and dendrograms. The present method does not rely on a “one to one” interaction, unlike conventional biodetection, and advantages can be envisaged in the case of an undefined or unknown cause of disease. The statistical analyses, such as multivariate analyses, allow classification of the type of proteins added in saliva as mimetics of disease. PepTenChip® system is useful and convenient for examination of periodontal disease in health care.     

Peculiarities of disorders of brain bioelectrical activity spatial-time organization in patients with different consciousness depression after severe head injury

Specific changes of bioelectrical brain activity was found in 27 patients with different level of posttraumatic consciousness depression by the methods of crosscorrelation, coherence and factor analysis of EEG. The changes of activity of morphofunctional systems of intracerebral integrations were revealed partially by decreasing of unspecific activity from brainstem structures reflected with increasing of slow wave activity and decreasing of EEG coherence in alpha- and beta-range. Depression of system organization of interconnections of bioelectrical brain activity in frontal and occipital regions of both hemispheres was also detected, and testified about decreasing of intercortical and thalamocortical brain system action under brain dislocation. The changes of integrative brain system activity, provides interhemispheric interaction, had the specific characted. Our results propose a "facilitation" of activity of system, providing "direct" interhemispheric connections through corpus callosum and other commissural tracts of telencephalon as a sequel of mesodiencephalon structures depression with steady reciprocal, antiphase relations of slow weve activity in symmetrical areas of hemispheres in coma II patients. The data of our research had shown no complete disintegration of system brain activity in coma II patients in spite of consciousness and brainstem reflexes depression.     

The changes in the hemodynamic activity of the brain during motor imagery training with the use of brain-computer interface

With the use of functional MRI (fMRI), we studied the changes in brain hemodynamic activity of healthy subjects during motor imagery training with the use brain-computer interface (BCI), which is based on the recognition of EEG patterns of imagined movements. ANOVA dispersion analysis showed there are 14 areas of the brain where statistically significant changes were registered. Detailed analysis of the activity in these areas before and after training (Student’s and Mann-Whitney tests) showed that the real amount of such areas is five; these are Brodmann areas 44 and 45, insula, middle frontal gyrus and anterior cingulate gyrus. We suggest that these changed are caused by the formation of memory traces of those brain activity patterns which are most accurately recognized by BCI classifiers as correspondent with limb movements imagery. We also observed a tendency of increase in the activity of motor imagery after training. The hemodynamic activity in all these 14 areas during real movements was either approximately the same or significantly higher than during motor imagery; activity during imagined leg movements was higher than that during imagines arm movements, except for the areas of representation of arms.     

Gender difference in QTc prolongation of people with mental disorders

BACKGROUND: We examined gender difference in QTc interval distribution and its related factors in people with mental disorders. METHODS: We retrospectively reviewed medical charts of patients discharged from a university psychiatric unit between November 1997 and December 2000. Subjects were 328 patients (145 males and 183 females) taking psychotropics at their admission. We examined patient characteristics, medical history, diagnosis, and medication before admission. RESULTS: Mean QTc interval was 0.408 (SD = 0.036). QTc intervals in females were significantly longer than those in males. QTc of females without comorbidity was significantly longer than that of males. CONCLUSION: The influence of gender difference on QTc prolongation in people with mental disorders merits further research.     

Clinical correlates of chronotypes in young persons with mental disorders

While important changes in circadian rhythms take place during adolescence and young adulthood, it is unclear how circadian profiles during this period relate to emerging mental disorders. This study aimed to: (i) characterise morningness–eveningness preference in young people with primary anxiety, depression, bipolar or psychotic disorders as compared to healthy controls, and (ii) to investigate associations between morningness–eveningness preference and the severity of psychiatric symptoms. Four hundred and ninety-six males and females aged between 12 and 30 years were divided into five groups according to primary diagnosis. The Hamilton Depression Rating Scale and the Brief Psychiatric Rating Scale were administered by a research psychologist and participants completed the Kessler Psychological Distress Scale and the Horne–Östberg Morningness–Eveningness Questionnaire (ME). ME scores were significantly lower (i.e. higher levels of “eveningness”) in all patient diagnosis subgroups compared to the control group. The psychosis group had higher ME scores than the depression and anxiety groups. Compared to the control group, the anxiety, depression and bipolar subgroups had a significantly higher proportion of “moderate evening” types, with a similar trend for the psychosis group. The proportion of “extreme evening” types was significantly higher in the anxiety and depression subgroups than in the control group. Lower ME scores correlated with worse psychological distress in males from the bipolar group. Lower ME scores correlated with higher depression severity in females with depression and in males with bipolar disorder. These results suggest that young persons with various mental disorders, especially those with affective disorders, present with a stronger “eveningness” preference and higher rates of evening chronotypes than healthy controls from the same age group. Later chronotypes were generally associated with worse psychological distress and symptoms severity. These associations were modulated by sex and primary diagnosis.