Single-trial extraction of event-related potentials (ERPs) and classification of visual stimuli by ensemble use of discrete wavelet transform with Huffman coding and machine learning techniques.

BACKGROUND: Presentation of visual stimuli can induce changes in EEG signals that are typically detectable by averaging together data from multiple trials for individual participant analysis as well as for groups or conditions analysis of multiple participants. This study proposes a new method based on the discrete wavelet transform with Huffman coding and machine learning for single-trial analysis of evenal (ERPs) and classification of different visual events in the visual object detection task. METHODS: EEG single trials are decomposed with discrete wavelet transform (DWT) up to the [Formula: see text] level of decomposition using a biorthogonal B-spline wavelet. The coefficients of DWT in each trial are thresholded to discard sparse wavelet coefficients, while the quality of the signal is well maintained. The remaining optimum coefficients in each trial are encoded into bitstreams using Huffman coding, and the codewords are represented as a feature of the ERP signal. The performance of this method is tested with real visual ERPs of sixty-eight subjects. RESULTS: The proposed method significantly discards the spontaneous EEG activity, extracts the single-trial visual ERPs, represents the ERP waveform into a compact bitstream as a feature, and achieves promising results in classifying the visual objects with classification performance metrics: accuracies 93.60[Formula: see text], sensitivities 93.55[Formula: see text], specificities 94.85[Formula: see text], precisions 92.50[Formula: see text], and area under the curve (AUC) 0.93[Formula: see text] using SVM and k-NN machine learning classifiers. CONCLUSION: The proposed method suggests that the joint use of discrete wavelet transform (DWT) with Huffman coding has the potential to efficiently extract ERPs from background EEG for studying evoked responses in single-trial ERPs and classifying visual stimuli. The proposed approach has O(N) time complexity and could be implemented in real-time systems, such as the brain-computer interface (BCI), where fast detection of mental events is desired to smoothly operate a machine with minds.

Transplantation of IGF-1-induced BMSC-derived NPCs promotes tissue repair and motor recovery in a rat spinal cord injury model.

Bone marrow-derived mesenchymal stem cells (BMSCs) have therapeutic potential for spinal cord injury (SCI). We have shown that insulin-like growth factor 1 (IGF-1) enhances the cellular proliferation and survivability of BMSCs-derived neural progenitor cells (NPCs) by downregulating miR-22-3p. However, the functional application of BMSCs-derived NPCs has not been investigated fully. In this study, we demonstrate that knockdown of endogenous miR-22-3p in BMSCs-derived NPCs upregulates Akt1 expression, leading to enhanced cellular proliferation. RNASeq analysis reveals 3,513 differentially expressed genes in NPCs. The upregulated genes in NPCs enrich the gene ontology term associated with nervous system development. Terminally differentiated NPCs generate cells with neuronal-like morphology and phenotypes. Transplantation of NPCs in the SCI rat model results in better recovery in locomotor and sensory functions 4 weeks after transplantation. Altogether, the result of this study demonstrate that NPCs derived with IGF-1 supplementation could be differentiated into functional neural lineage cells and are optimal for stem cell therapy in SCI.

A Comparative Study Across Methods to Identify Adolescents with Syntactic Specific Language Impairment.

Background: Specific language impairment (SLI) is described as a heterogeneous deficit that causes difficulties in various aspects of language. We performed a comparative study of two methods of language assessment with the primary objective of determining the most effective approach for identifying adolescents with syntactic SLI and typical development (TD) in use. Methods: A software-assisted method using E-Prime 2.0 was used to create an experiment. The participants were Malay adolescents aged 13 years old-15 years old. The conventional method was compared with the software-assisted method to assess the participants' comprehension and production performance. Data on reaction time (RT), scoring and no response (NR) were obtained from the adolescents. Results: Based on the two methods, the findings on the selection of participants for the SLI and TD groups was different. The two methods produced similar results in terms of the selection of TD group and most participants in the syntactic SLI group except for two participants who failed in the conventional method but passed the test in the software-assisted method. Conclusion: The descriptive evaluation of the findings suggested selecting software-assisted method as the alternative source because the provided information was detailed and this information enabled the researcher to identify the SLI group.

Post-Attentive Integration and Topographic Map Distribution During Audiovisual Processing in Dyslexia: A P300 Event-Related Component Analysis.

BACKGROUND: Research on audiovisual post-attentive integration has been carried out using a variety of experimental paradigms and experimental groups but not yet studied in dyslexia. We investigated post-attentive integration and topographic voltage distribution in children with dyslexia by analysing the P300 event-related potential (ERP) component. METHODS: We used a 128-child ERP net for the ERP experiment. Two types of stimuli were presented as either congruent or incongruent stimuli. Congruent stimuli included a matching auditory sound with an animal image, whereas incongruent stimuli included unmatched animal sounds. A total of 24 age-matched children were recruited in the control (n = 12) and dyslexia (n = 12) groups. Children pressed button '1' or '2' when presented with congruent or incongruent stimuli, respectively. The P300 amplitudes and latencies with topographic voltage distribution were analysed for both groups. RESULTS: The dyslexia group evoked significantly higher P300 amplitudes at the T4 area than the control group. No significant differences were found in cases of P300 latency. Moreover, the dyslexia group demonstrated a higher intensity of P300 voltage distribution in the right parietal and left occipital areas than the control group. CONCLUSION: Post-attentive integration for children with dyslexia is higher and that this integration process implicated the parietal and occipital areas.

The Effect of Sex on the Electropsychological Process of Emotional Arousal Intensity.

BACKGROUND: Sex is a psychobiological factor that is important in the process of emotion. This study determines the effect of sex on the electropsychological process of various intensities of emotional arousal. METHODS: In the Event-related Potential (ERP) session, electroencephalographic (EEG) data was recorded for 90 participants, 60% of whom were females. The participants responded to 30 universal emotional pictures, randomly chosen from the International Affective Picture System (IAPS), which were classified as invoking high, moderate, and low intensity of emotional arousal. RESULTS: From the analysis of variance of two-way mixed design, the interaction between sex and emotional intensity was observed in the occipital regions (O2), indexed by the amplitude of P300 and N200 components. Males exhibited higher amplitude of P300 and N200 components (in the occipital region) as responded to high and low emotional arousal stimuli than females. CONCLUSION: Sex is a fundamental factor that modulates psychological states in reaction to emotional stimuli.

How Much We Think of Ourselves and How Little We Think of Others: An Investigation of the Neuronal Signature of Self-Consciousness between Different Personality Traits through an Event-Related Potential Study.

BACKGROUND: Previous studies have revealed that self-related tasks (items) receive more attention than non-self-related, and that they elicit event-related potential (ERP) components with larger amplitudes. Since personality has been reported as one of the biological correlates influencing these components, as well as our behavioural differences, it is important to examine how it affects our self-consciousness in relation to tasks of varied relevance and the neurological basis. METHODS: A total of 33 male and female undergraduate Malaysian medical students of Universiti Sains Malaysia (USM) participated in the study. The participants were divided into two groups, Ambivert (n = 18) and Extravert (n = 15) groups, using the USM personality inventory questionnaire. In the ERP experiment, squares containing standard stimuli of any word other than self and non-self-related nouns (e.g., Bola, Gigi, Anak, etc.; in English: Ball, Teeth, Kids, etc., respectively), those containing self-related pronouns (Saya, Kami or Kita; in English: I, Us or We, respectively), and non-self-related pronouns (Dia, Anda or Mereka; in English: He/She, You or They, respectively), were shown 58%, 21% and 21% of the time, respectively, in a three-stimulus visual oddball paradigm. All words were presented in Bahasa Melayu. The participants were instructed to press 1 for self and 2 for non-self, and ignore standard stimuli. RESULTS: Comparison of both N200 and P300 amplitudes for self-related and non-self-related pronouns in the Extravert group revealed significant differences at seven electrode sites, with self-related having larger amplitude at anterior electrodes and less at posterior. This was not seen in the Ambivert group. CONCLUSION: The present study suggests that self-relevant pronouns are psychologically more important to extraverts than to ambiverts; hence, they have more self-awareness. This may be due to large amount of dopamine in the brains of extraverts, which is more concentrated in the frontal lobe.

N200 latency and P300 amplitude in depressed mood post-traumatic brain injury patients.

In order to examine the independent and combined effects of depressive symptoms and traumatic brain injury on event-related potential (ERP) components, we classified traumatic brain injury (TBI) patients as depressed and non-depressed mood according to their scores on the Zung Self-rating Depression Scale (SDS). Non-depressed mood post-traumatic brain injury patients (NondepTBI, n=9), depressed mood post-traumatic brain injury patients (DepTBI, n=26), and normal healthy control subjects (HC, n=10) were assessed for N100, N200, and P300 latencies and amplitudes by the auditory "oddball paradigm". DepTBI subjects had significantly prolonged N200 latency and low P300 amplitude compared with the NondepTBI and HC groups. A longer P300 latency in the NondepTBI and DepTBI than in the HC groups was found. A prolongation of N200 latency accompanied by low P300 amplitude may be a characteristic of post-traumatic brain injury patients with depressed mood. Prolonged P300 latency may be more closely associated with TBI than with depression, as it was significantly greater in both the DepTBI and NondepTBI, than in the HC group.

Mechanomyographic response to transcranial magnetic stimulation from biceps brachii and during transcutaneous electrical nerve stimulation on extensor carpi radialis.

Transcranial magnetic stimulation (TMS) elicits short latency excitatory responses in the target muscles, termed motor evoked potential (MEP). When TMS is delivered during a voluntary contraction, the MEP is followed by a period of silence called silent period (SP). These MEP parameters are in general recordable by electromyography (EMG). Mechanomyography (MMG) on the other hand is the mechanical counterpart of EMG. Thus, this study has been conducted to observe whether the MEP parameters from MMG signals showed similar trait of EMG recordings. Five normal healthy male subjects were included in this study. The subjects were required to perform right biceps brachii muscles contraction at diverse graded of load level at 5, 10, 20, 30, 40, 60, and 100% maximum voluntary contraction (MVC). MEPs by single pulse TMS on left hemisphere were obtained from both EMG electrode and MMG accelerometer at rest and at different levels of predetermined load level. MEP amplitude and area obtained both from EMG and MMG record were increased with the increase of muscle contraction with a maximum of 60% MVC. With increasing the level of contraction there was a shortening of onset latency and decreasing in the length of silent period in both EMG and MMG signals. We also recorded the EMG- and MMG-MEP from the right extensor carpi radialis muscle during transcutaneous electric nerve stimulation in order to observe neural changes in sensory stimulation from both EMG and MMG responses. The EMG-MEP was not visible in electrical artifact whereas it was obvious in MMG responses. In accordance with other study, this study showed that the voluntary contraction of biceps brachii muscle influenced the MEP parameter which are moreover obtainable by MMG even in electrical noise may provide insight for future study.

Evaluation of a new physical exercise taken from salat (prayer) as a short-duration and frequent physical activity in the rehabilitation of geriatric and disabled patients.

BACKGROUND: The major function of rehabilitation and physical medicine specialists is to provide the proper therapy that helps in improving the physical activities of impaired, disabled and handicapped persons through improvement in their muscle strength. In performing their function, the rehabilitation team should always take heed of the social and mental well-being of such patients. Having observed millions of Muslims perform the salat (prayer) regularly at specified times throughout the world, we postulated that salat, along with its various postures, can play a role in increasing psychological well-being including self-reliance and self-esteem, improving musculo-skeletal fitness, motor behavior and cerebral blood flow that may be beneficial in the rehabilitation of geriatric and disabled persons. SUBJECTS AND METHODS: The various postures of salat were studied and a range of joint motions were measured by goniometer, an instrument for measuring angles. Brain blood pressure was calculated from the effect of gravity on blood pressure at different positions. RESULTS: We found that during the offering of salat, most of the joints and muscles of the body were involved in physical activities with little effort, which probably play a vital role in cerebral blood flow and postural reflexes. CONCLUSION: The physical activities involved in the performance of salat helps in the rehabilitation process in disabled geriatric patients by improving blood flow and increasing musculoskeletal fitness. The salat prayer involves little effort (standing, bowing, prostration and sitting), has a short duration and is beneficial for mental and physical health. More studies are needed in future to determine the full beneficial effects of the salat prayer on the rehabilitative process of disabled persons.